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Ramesh Sawant A, Pagal S, Prashanth K. Role of the NtrC family response regulator in nitrogen metabolism of Acinetobacter baumannii. Gene 2024; 924:148552. [PMID: 38734189 DOI: 10.1016/j.gene.2024.148552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Acinetobacter baumannii is an important Gram-negative nosocomial pathogen that causes opportunistic infections and employs different mechanisms to survive in the presence of antibiotics in the host. Nutrient limitation is one of the important defense mechanisms of the mammalian immune system to fight against the colonization of pathogens like A. baumannii. The present study describes an NtrC-type Response Regulator (RR) A1S_1978 involved in modulating the metabolism and cell morphology of A. baumannii via a two-component system. This RR was found to be highly conserved in the Acinetobacter and other important Gram-negative pathogens. Sequence analysis reveals that this RR contains an HTH_8 DNA-binding domain. It is also observed that deletion of this RR resulted in elongated cell phenotype and altered colony morphology of A. baumannii. We showed that the ability of A. baumannii to form biofilm and pellicle is partly abolished upon deletion of this response regulator. We showed that mutant strains lacking RR A1S_1978 have diminished growth in the absence of the nitrogen source. The transcriptome analysis of the A1S_1978 deletion mutant revealed that 253 genes were differentially expressed, including 80 genes that were upregulated by at least 2-fold and 173 genes that were down regulated in the ΔA1S_1978 strain. The transcriptome data showed an association between the A1S_1978 RR and key genes related to various nitrogen and amino acid metabolism processes, which was further confirmed by real time PCR analysis. The deletion of this RR leads to a reduction in persister cell formation against ciprofloxacin antibiotic. Taken together the results of this investigation provide significant evidence that the RR A1S_1978 is a global regulator in A. baumannii.
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Affiliation(s)
- Ajit Ramesh Sawant
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Sudhakar Pagal
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - K Prashanth
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India.
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2
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Zhou W, Hao J, Guo Y, Zhao C, Zhang M, Zhang S, Han F. Revealing bioresponses of biofilm and flocs to salinity gradient in halophilic biofilm reactor. BIORESOURCE TECHNOLOGY 2024; 401:130727. [PMID: 38643952 DOI: 10.1016/j.biortech.2024.130727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/09/2024] [Accepted: 04/18/2024] [Indexed: 04/23/2024]
Abstract
Understanding the different biological responses to salinity gradient between coexisting biofilm and flocs is crucial for regulating the ecological function of biofilm system. This study investigated performance, dynamics, and community assembly of biofilm system under 3 %-7% salinity gradient. The removal efficiency of NH4+-N remained stable and exceeded 93 % at 3 %-6% salinity, but decreased to below 80 % at 7 % salinity. The elevated salinity promoted the synthesis of extracellular polymer substrates, inhibited microbial respiration, and significantly regulated the microbial community structure. Compared to flocs, biofilm exhibited greater species diversity and richer Nitrosomonas. It was found diffusion limitations dominated the microbial community assembly under the salinity gradient. And microbial network revealed positive interactions predominated the microbial relationships, designating norank Spirochaetaceae, unclassified Micrococcales, Corynebacterium, and Pusillimonas as keystone species. Moreover, distinct salinity preferences in nitrogen transformation-related genes were observed. This study can improve the understanding to the regulation of biofilm systems to salt stresses.
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Affiliation(s)
- Weizhi Zhou
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Jie Hao
- School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266000, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Yiting Guo
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Chuanfu Zhao
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Mengru Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Shuhui Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China
| | - Fei Han
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, China.
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3
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Mott PD, Zea AH, Lewis J, Mirzalieva O, Aiyar AA. Serine deamination by human serine racemase synergizes with antibiotics to curtail the replication of Chlamydia trachomatis. J Biol Chem 2024; 300:107350. [PMID: 38718865 PMCID: PMC11140210 DOI: 10.1016/j.jbc.2024.107350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/28/2024] [Accepted: 04/30/2024] [Indexed: 05/28/2024] Open
Abstract
The obligate intracellular bacterium, Chlamydia trachomatis, has evolved to depend on its human host for many metabolites, including most amino acids and three of the four nucleotides. Given this, it is not surprising that depletion of a single amino acid in the host cell growth medium blocks chlamydial replication. Paradoxically, supra-normal levels of some amino acids also block productive replication of Chlamydia. Here, we have determined how elevated serine levels, generated by exogenous supplementation, impede chlamydial inclusion development and reduce the generation of infectious progeny. Our findings reveal that human serine racemase, which is broadly expressed in multiple tissues, potentiates the anti-chlamydial effect of elevated serine concentrations. In addition to reversibly converting l-serine to d-serine, serine racemase also deaminates serine via β-elimination. We have determined that d-serine does not directly impact Chlamydia; rather, ammonia generated by serine deamination limits the productive chlamydial replication. Our findings imply that ammonia produced within host cells can traverse the chlamydial inclusion membrane. Further, this property of serine deaminase can be exploited to sensitize Chlamydia to concentrations of doxycycline that are otherwise not bactericidal. Because exogenously elevated levels of serine can be tolerated over extended periods, the broad expression pattern of serine racemase indicates it to be a host enzyme whose activity can be directed against multiple intracellular bacterial pathogens. From a therapeutic perspective, demonstrating host metabolism can be skewed to generate an anti-bacterial metabolite that synergizes with antibiotics, we believe our results provide a new approach to target intracellular pathogens.
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Affiliation(s)
- Patricia D Mott
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
| | - Arnold H Zea
- Department of Microbiology, Immunology, & Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Jamiya Lewis
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Oygul Mirzalieva
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Ashok A Aiyar
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
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4
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Liu X, Li J, Zhang Z, He Y, Wang M, Zhao Y, Lin S, Liu T, Liao Y, Zhang N, Yuan K, Ling Y, Liu Z, Chen X, Chen Z, Chen R, Wang X, Gu B. Acetylation of xenogeneic silencer H-NS regulates biofilm development through the nitrogen homeostasis regulator in Shewanella. Nucleic Acids Res 2024; 52:2886-2903. [PMID: 38142446 PMCID: PMC11014242 DOI: 10.1093/nar/gkad1219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/26/2023] Open
Abstract
Adjusting intracellular metabolic pathways and adopting suitable live state such as biofilms, are crucial for bacteria to survive environmental changes. Although substantial progress has been made in understanding how the histone-like nucleoid-structuring (H-NS) protein modulates the expression of the genes involved in biofilm formation, the precise modification that the H-NS protein undergoes to alter its DNA binding activity is still largely uncharacterized. This study revealed that acetylation of H-NS at Lys19 inhibits biofilm development in Shewanella oneidensis MR-1 by downregulating the expression of glutamine synthetase, a critical enzyme in glutamine synthesis. We further found that nitrogen starvation, a likely condition in biofilm development, induces deacetylation of H-NS and the trimerization of nitrogen assimilation regulator GlnB. The acetylated H-NS strain exhibits significantly lower cellular glutamine concentration, emphasizing the requirement of H-NS deacetylation in Shewanella biofilm development. Moreover, we discovered in vivo that the activation of glutamine biosynthesis pathway and the concurrent suppression of the arginine synthesis pathway during both pellicle and attached biofilms development, further suggesting the importance of fine tune nitrogen assimilation by H-NS acetylation in Shewanella. In summary, posttranslational modification of H-NS endows Shewanella with the ability to respond to environmental needs by adjusting the intracellular metabolism pathways.
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Affiliation(s)
- Xiaoxiao Liu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Jun Li
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhixuan Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
- School of Medicine, South China University of Technology, Guangzhou, Guangdong 510080, China
| | - Yizhou He
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Mingfang Wang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yunhu Zhao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianlang Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiwen Liao
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ni Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Kaixuan Yuan
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Yong Ling
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Ziyao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaozhong Chen
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
| | - Zhe Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ran Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bing Gu
- Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510000, China
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Zhao C, Jiao T, Zhang W, Zhang W, Jia M, Liu S, Zhang M, Han F, Han Y, Lei J, Wang X, Zhou W. Nutrients recovery by coupled bioreactor of heterotrophic ammonia assimilation and microbial fuel cell in saline wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170697. [PMID: 38331272 DOI: 10.1016/j.scitotenv.2024.170697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/24/2024] [Accepted: 02/02/2024] [Indexed: 02/10/2024]
Abstract
Heterotrophic ammonia assimilation (HAA) process had been widely used in the treatment of high salt wastewater, but the electro enhanced coupling process and electron transfer process were rarely studied. In this study, a HAA process coupled microbial fuel cell (MFC) system was established to treat ammonia-containing wastewater under increasing salinity to achieve nitrogen recovery and electricity generation. Up to 95.4 % NH4+-N and 96.4 % COD removal efficiencies were achieved at 2 % salinity in HAA-MFC. The maximum power density and current density at 2 % salinity were 29.93 mW/m2 and 182.37 mA/m2, respectively. The residual organic matter in the cathode effluent was effectively removed by the anode. The increase of salinity not only enhanced the sludge settling performance and activity, but also promoted the enzyme activity and amino acid production of the ammonia assimilation pathway. Marinobacter and Halomonas were gradually enriched at the anode and cathode with increased salinity to promote ammonia assimilation and electron production. This research offered a promising solution to overcome salinity-related challenges in wastewater treatment and resource recovery.
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Affiliation(s)
- Chuanfu Zhao
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Tong Jiao
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Wenhao Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Wenchao Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Man Jia
- Shandong Provincial Eco-Environment Monitoring Center, Jinan, Shandong, PR China
| | - Sheng Liu
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Mengru Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Fei Han
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Yufei Han
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Jianhua Lei
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China
| | - Xianfeng Wang
- Shandong Provincial Eco-Environment Monitoring Center, Jinan, Shandong, PR China.
| | - Weizhi Zhou
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China.
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6
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Urs K, Zimmern PE, Reitzer L. Abundant urinary amino acids activate glutamine synthetase-encoding glnA by two different mechanisms in Escherichia coli. J Bacteriol 2024; 206:e0037623. [PMID: 38358279 PMCID: PMC10955845 DOI: 10.1128/jb.00376-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/31/2024] [Indexed: 02/16/2024] Open
Abstract
Growth of uropathogenic Escherichia coli in the bladder induces transcription of glnA which codes for the ammonia-assimilating glutamine synthetase (GS) despite the normally suppressive high ammonia concentration. We previously showed that the major urinary component, urea, induces transcription from the Crp-dependent glnAp1 promoter, but the urea-induced transcript is not translated. Our purpose here was to determine whether the most abundant urinary amino acids, which are known to inhibit GS activity in vitro, also affect glnA transcription in vivo. We found that the abundant amino acids impaired growth, which glutamine and glutamate reversed; this implies inhibition of GS activity. In strains with deletions of crp and glnG that force transcription from the glnAp2 and glnAp1 promoters, respectively, we examined growth and glnA transcription with a glnA-gfp transcriptional fusion and quantitative reverse transcription PCR with primers that can distinguish transcription from the two promoters. The abundant urinary amino acids stimulated transcription from the glnAp2 promoter in the absence of urea but from the glnAp1 promoter in the presence of urea. However, transcription from glnAp1 did not produce a translatable mRNA or GS as assessed by a glnA-gfp translational fusion, enzymatic assay of GS, and Western blot to detect GS antigen in urea-containing media. We discuss these results within the context of the extremely rapid growth of uropathogenic E. coli in urine, the different factors that control the two glnA promoters and possible mechanisms that either overcome or bypass the urea-imposed block of glutamine synthesis during bacterial growth in urine.IMPORTANCEKnowledge of the regulatory mechanisms for genes expressed at the site of infection provides insight into the virulence of pathogenic bacteria. During urinary tract infections-most often caused by Escherichia coli-growth in urine induces the glnA gene which codes for glutamine synthetase. The most abundant urinary amino acids amplified the effect of urea which resulted in hypertranscription from the glnAp1 promoter and, unexpectedly, an untranslated transcript. E. coli must overcome this block in glutamine synthesis during growth in urine, and the mechanism of glutamine acquisition or synthesis may suggest a possible therapy.
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Affiliation(s)
- Karthik Urs
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Philippe E. Zimmern
- Department of Urology, University of Texas Southwestern Medical School, Dallas, Texas, USA
| | - Larry Reitzer
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
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7
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Lozano-Terol G, Chiozzi RZ, Gallego-Jara J, Sola-Martínez RA, Vivancos AM, Ortega Á, Heck AJ, Díaz MC, de Diego Puente T. Relative impact of three growth conditions on the Escherichia coli protein acetylome. iScience 2024; 27:109017. [PMID: 38333705 PMCID: PMC10850759 DOI: 10.1016/j.isci.2024.109017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 12/04/2023] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
Nε-lysine acetylation is a common posttranslational modification observed in Escherichia coli. In the present study, integrative analysis of the proteome and acetylome was performed using label-free quantitative mass spectrometry to analyze the relative influence of three factors affecting growth. The results revealed differences in the proteome, mainly owing to the type of culture medium used (defined or complex). In the acetylome, 7482 unique acetylation sites were identified. Acetylation is directly related to the abundance of proteins, and the level of acetylation in each type of culture is associated with extracellular acetate concentration. Furthermore, most acetylated lysines in the exponential phase remained in the stationary phase without dynamic turnover. Interestingly, unique acetylation sites were detected in proteins whose presence or abundance was linked to the type of culture medium. Finally, the biological function of the acetylation changes was demonstrated for three central metabolic proteins (GapA, Mdh, and AceA).
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Affiliation(s)
- Gema Lozano-Terol
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Riccardo Zenezini Chiozzi
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padulaan 8, Utrecht 3584 CH, the Netherlands
| | - Julia Gallego-Jara
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Rosa Alba Sola-Martínez
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Adrián Martínez Vivancos
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Álvaro Ortega
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Albert J.R. Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padulaan 8, Utrecht 3584 CH, the Netherlands
| | - Manuel Cánovas Díaz
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
| | - Teresa de Diego Puente
- Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence “Campus Mare Nostrum”, 30100 Murcia, Spain
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8
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Miyakoshi M. Multilayered regulation of amino acid metabolism in Escherichia coli. Curr Opin Microbiol 2024; 77:102406. [PMID: 38061078 DOI: 10.1016/j.mib.2023.102406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 02/12/2024]
Abstract
Amino acid metabolism in Escherichia coli has long been studied and has established the basis for regulatory mechanisms at the transcriptional, posttranscriptional, and posttranslational levels. In addition to the classical signal transduction cascade involving posttranslational modifications (PTMs), novel PTMs in the two primary nitrogen assimilation pathways have recently been uncovered. The regulon of the master transcriptional regulator NtrC is further expanded by a small RNA derived from the 3´UTR of glutamine synthetase mRNA, which coordinates central carbon and nitrogen metabolism. Furthermore, recent advances in sequencing technologies have revealed the global regulatory networks of transcriptional and posttranscriptional regulators, Lrp and GcvB. This review provides an update of the multilayered and interconnected regulatory networks governing amino acid metabolism in E. coli.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Infection Biology, Institute of Medicine, University of Tsukuba, 305-8575 Ibaraki, Japan.
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Hassan Z, Westerhoff HV. Arsenic Contamination of Groundwater Is Determined by Complex Interactions between Various Chemical and Biological Processes. TOXICS 2024; 12:89. [PMID: 38276724 PMCID: PMC11154318 DOI: 10.3390/toxics12010089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/27/2024]
Abstract
At a great many locations worldwide, the safety of drinking water is not assured due to pollution with arsenic. Arsenic toxicity is a matter of both systems chemistry and systems biology: it is determined by complex and intertwined networks of chemical reactions in the inanimate environment, in microbes in that environment, and in the human body. We here review what is known about these networks and their interconnections. We then discuss how consideration of the systems aspects of arsenic levels in groundwater may open up new avenues towards the realization of safer drinking water. Along such avenues, both geochemical and microbiological conditions can optimize groundwater microbial ecology vis-à-vis reduced arsenic toxicity.
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Affiliation(s)
- Zahid Hassan
- Department of Molecular Cell Biology, A-Life, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands;
- Department of Genetic Engineering and Biotechnology, Jagannath University, Dhaka 1100, Bangladesh
| | - Hans V. Westerhoff
- Department of Molecular Cell Biology, A-Life, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands;
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
- Synthetic Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Stellenbosch Institute of Advanced Studies (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch 7600, South Africa
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10
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Howard-Varona C, Lindback MM, Fudyma JD, Krongauz A, Solonenko NE, Zayed AA, Andreopoulos WB, Olson HM, Kim YM, Kyle JE, Glavina del Rio T, Adkins JN, Tfaily MM, Paul S, Sullivan MB, Duhaime MB. Environment-specific virocell metabolic reprogramming. THE ISME JOURNAL 2024; 18:wrae055. [PMID: 38552150 PMCID: PMC11170926 DOI: 10.1093/ismejo/wrae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/23/2023] [Accepted: 03/28/2024] [Indexed: 06/14/2024]
Abstract
Viruses impact microbial systems through killing hosts, horizontal gene transfer, and altering cellular metabolism, consequently impacting nutrient cycles. A virus-infected cell, a "virocell," is distinct from its uninfected sister cell as the virus commandeers cellular machinery to produce viruses rather than replicate cells. Problematically, virocell responses to the nutrient-limited conditions that abound in nature are poorly understood. Here we used a systems biology approach to investigate virocell metabolic reprogramming under nutrient limitation. Using transcriptomics, proteomics, lipidomics, and endo- and exo-metabolomics, we assessed how low phosphate (low-P) conditions impacted virocells of a marine Pseudoalteromonas host when independently infected by two unrelated phages (HP1 and HS2). With the combined stresses of infection and nutrient limitation, a set of nested responses were observed. First, low-P imposed common cellular responses on all cells (virocells and uninfected cells), including activating the canonical P-stress response, and decreasing transcription, translation, and extracellular organic matter consumption. Second, low-P imposed infection-specific responses (for both virocells), including enhancing nitrogen assimilation and fatty acid degradation, and decreasing extracellular lipid relative abundance. Third, low-P suggested virocell-specific strategies. Specifically, HS2-virocells regulated gene expression by increasing transcription and ribosomal protein production, whereas HP1-virocells accumulated host proteins, decreased extracellular peptide relative abundance, and invested in broader energy and resource acquisition. These results suggest that although environmental conditions shape metabolism in common ways regardless of infection, virocell-specific strategies exist to support viral replication during nutrient limitation, and a framework now exists for identifying metabolic strategies of nutrient-limited virocells in nature.
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Affiliation(s)
- Cristina Howard-Varona
- Department of Microbiology, The Ohio State University, 484 W 12th Ave, Columbus, OH 43210, United States
| | - Morgan M Lindback
- Department of Ecology and Evolutionary Biology, University of Michigan, 1105 North University Ave, Ann Arbor, MI 48109, United States
| | - Jane D Fudyma
- Department of Environmental Science, University of Arizona, 1177 E 4th St, Tucson, AZ 85719, United States
- Present address: Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Azriel Krongauz
- Department of Statistics, The Ohio State University, 1958 Neil Ave, Columbus, OH 43210, United States
| | - Natalie E Solonenko
- Department of Microbiology, The Ohio State University, 484 W 12th Ave, Columbus, OH 43210, United States
| | - Ahmed A Zayed
- Department of Microbiology, The Ohio State University, 484 W 12th Ave, Columbus, OH 43210, United States
| | - William B Andreopoulos
- US Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, United States
- Present address: Department of Computer Science, San Jose State University, One Washington Square, San Jose CA 95192, United States
| | - Heather M Olson
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, United States
| | - Young-Mo Kim
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, United States
| | - Jennifer E Kyle
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, United States
| | - Tijana Glavina del Rio
- US Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, United States
| | - Joshua N Adkins
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99354, United States
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR 97239, United States
| | - Malak M Tfaily
- Department of Environmental Science, University of Arizona, 1177 E 4th St, Tucson, AZ 85719, United States
| | - Subhadeep Paul
- Department of Statistics, The Ohio State University, 1958 Neil Ave, Columbus, OH 43210, United States
| | - Matthew B Sullivan
- Department of Microbiology, The Ohio State University, 484 W 12th Ave, Columbus, OH 43210, United States
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, 2070 Neil Ave, Columbus, OH 43210, United States
- Center for RNA Biology and Center of Microbiome Science, The Ohio State University, 484 W. 12th Ave, Columbus, OH 43210, United States
| | - Melissa B Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, 1105 North University Ave, Ann Arbor, MI 48109, United States
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11
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Marogi JG, Murphy CT, Myhrvold C, Gitai Z. P. aeruginosa controls both C. elegans attraction and pathogenesis by regulating nitrogen assimilation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569279. [PMID: 38077073 PMCID: PMC10705433 DOI: 10.1101/2023.11.29.569279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2024]
Abstract
Detecting chemical signals is important for identifying food sources and avoiding harmful agents. Like most animals, C. elegans use olfaction to chemotax towards their main food source, bacteria. However, little is known about the bacterial compounds governing C. elegans attraction to bacteria and the physiological importance of these compounds to bacteria. Here, we address these questions by investigating the function of a small RNA, P11, in the pathogen, Pseudomonas aeruginosa, that was previously shown to mediate learned pathogen avoidance. We discovered that this RNA also affects the attraction of untrained C. elegans to P. aeruginosa and does so by controlling production of ammonia, a volatile odorant produced during nitrogen assimilation. We untangle the complex regulation of P. aeruginosa nitrogen assimilation, which is mediated by a partner-switching mechanism involving environmental nitrates, sensor proteins, and P11. In addition to mediating C. elegans attraction, nitrogen assimilation is important for bacterial fitness and pathogenesis during C. elegans infection by P. aeruginosa . These studies define ammonia as a major mediator of trans-kingdom signaling, reveal the physiological importance of nitrogen assimilation for both bacteria and host organisms, and highlight how a bacterial metabolic pathway can either benefit or harm a host in different contexts.
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12
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Tang Y, Qin D, Tian Z, Chen W, Ma Y, Wang J, Yang J, Yan D, Dixon R, Wang YP. Diurnal switches in diazotrophic lifestyle increase nitrogen contribution to cereals. Nat Commun 2023; 14:7516. [PMID: 37980355 PMCID: PMC10657418 DOI: 10.1038/s41467-023-43370-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/07/2023] [Indexed: 11/20/2023] Open
Abstract
Uncoupling of biological nitrogen fixation from ammonia assimilation is a prerequisite step for engineering ammonia excretion and improvement of plant-associative nitrogen fixation. In this study, we have identified an amino acid substitution in glutamine synthetase, which provides temperature sensitive biosynthesis of glutamine, the intracellular metabolic signal of the nitrogen status. As a consequence, negative feedback regulation of genes and enzymes subject to nitrogen regulation, including nitrogenase is thermally controlled, enabling ammonia excretion in engineered Escherichia coli and the plant-associated diazotroph Klebsiella oxytoca at 23 °C, but not at 30 °C. We demonstrate that this temperature profile can be exploited to provide diurnal oscillation of ammonia excretion when variant bacteria are used to inoculate cereal crops. We provide evidence that diurnal temperature variation improves nitrogen donation to the plant because the inoculant bacteria have the ability to recover and proliferate at higher temperatures during the daytime.
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Affiliation(s)
- Yuqian Tang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Debin Qin
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Zhexian Tian
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Wenxi Chen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Yuanxi Ma
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jilong Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jianguo Yang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Dalai Yan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China.
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13
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Dhatt PS, Chiu S, Moon TS. Microbial thermogenesis is dependent on ATP concentrations and the protein kinases ArcB, GlnL, and YccC. PLoS Biol 2023; 21:e3002180. [PMID: 37862351 PMCID: PMC10619766 DOI: 10.1371/journal.pbio.3002180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 11/01/2023] [Accepted: 09/14/2023] [Indexed: 10/22/2023] Open
Abstract
Organisms necessarily release heat energy in their pursuit of survival. This process is known as cellular thermogenesis and is implicated in many processes from cancer metabolism to spontaneous farm fires. However, the molecular basis for this fundamental phenomenon is yet to be elucidated. Here, we show that the major players involved in the cellular thermogenesis of Escherichia coli are the protein kinases ArcB, GlnL, and YccC. We also reveal the substrate-level control of adenosine triphosphate (ATP)-driven autophosphorylation that governs cellular thermogenesis. Specifically, through live cell microcalorimetry, we find these regulatory proteins, when knocked out in a model E. coli strain, dysregulate cellular thermogenesis. This dysregulation can be seen in an average 25% or greater increase in heat output by these cells. We also discover that both heat output and intracellular ATP levels are maximal during the late log phase of growth. Additionally, we show that microbial thermogenesis can be engineered through overexpressing glnL. Our results demonstrate a correlation between ATP concentrations in the cell and a cell's ability to generate excess heat. We expect this work to be the foundation for engineering thermogenically tuned organisms for a variety of applications.
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Affiliation(s)
- Puneet Singh Dhatt
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Stephen Chiu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America
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14
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Han F, Zhao C, Zhang W, Jiao T, Zhang Z, Zhou W. Responses of halophilic microbial communities to changes in salt composition: Comparison between autotrophic nitrification and heterotrophic ammonia assimilation biosystems. BIORESOURCE TECHNOLOGY 2023; 386:129500. [PMID: 37468014 DOI: 10.1016/j.biortech.2023.129500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 07/21/2023]
Abstract
The concentration and proportion of chlorine (Cl-) and sulfate ions (SO42-) in actual high salinity wastewater exhibit significant fluctuations due to their diverse sources. This study compared the response of halophilic autotrophic nitrification (AN) and heterotrophic ammonia assimilation (HAA) sludges to changes in salt composition. The results demonstrated that both the AN and HAA systems maintained high ammonia removal efficiency even when exposed to mixed salt ions or pure sulfate conditions. Increasing the concentration of SO42- resulted in an increase in extracellular polymeric substances content, sludge settleability, sludge hydrophobicity, and the relative abundance of Nitrosomonas in the AN system (from 2.3% to 10.4%). The dominant heterotrophic bacteria in the HAA system underwent turnover in response to changes in salt composition conditions. The robustness and the cooperation between microorganisms of the HAA system surpassed those of the AN system. This study provides scientific foundation for treating multi-ion high salinity wastewater.
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Affiliation(s)
- Fei Han
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, PR China
| | - Chuanfu Zhao
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China
| | - Wenchao Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China
| | - Tong Jiao
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China
| | - Zixuan Zhang
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China
| | - Weizhi Zhou
- School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of Water-sediment Regulation and Eco-decontamination, Jinan, Shandong, PR China; School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong, PR China.
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15
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Zhao X, Song Y, Wang T, Hua C, Hu R, Shang Y, Shi H, Chen S. Glutamine synthetase and GlnR regulate nitrogen metabolism in Paenibacillus polymyxa WLY78. Appl Environ Microbiol 2023; 89:e0013923. [PMID: 37668407 PMCID: PMC10537745 DOI: 10.1128/aem.00139-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 07/12/2023] [Indexed: 09/06/2023] Open
Abstract
Paenibacillus polymyxa WLY78, a N2-fixing bacterium, has great potential use as a biofertilizer in agriculture. Recently, we have revealed that GlnR positively and negatively regulates the transcription of the nif (nitrogen fixation) operon (nifBHDKENXhesAnifV) in P. polymyxa WLY78 by binding to two loci of the nif promoter according to nitrogen availability. However, the regulatory mechanisms of nitrogen metabolism mediated by GlnR in the Paenibacillus genus remain unclear. In this study, we have revealed that glutamine synthetase (GS) and GlnR in P. polymyxa WLY78 play a key role in the regulation of nitrogen metabolism. P. polymyxa GS (encoded by glnA within glnRA) and GS1 (encoded by glnA1) belong to distinct groups: GSI-α and GSI-β. Both GS and GS1 have the enzyme activity to convert NH4+ and glutamate into glutamine, but only GS is involved in the repression by GlnR. GlnR represses transcription of glnRA under excess nitrogen, while it activates the expression of glnA1 under nitrogen limitation. GlnR simultaneously activates and represses the expression of amtBglnK and gcvH in response to nitrogen availability. Also, GlnR regulates the expression of nasA, nasD1D2, nasT, glnQHMP, and glnS. IMPORTANCE In this study, we have revealed that Paenibacillus polymyxa GlnR uses multiple mechanisms to regulate nitrogen metabolism. GlnR activates or represses or simultaneously activates and inhibits the transcription of nitrogen metabolism genes in response to nitrogen availability. The multiple regulation mechanisms employed by P. polymyxa GlnR are very different from Bacillus subtilis GlnR which represses nitrogen metabolism under excess nitrogen. Both GS encoded by glnA within the glnRA operon and GS1 encoded by glnA1 in P. polymyxa WLY78 are involved in ammonium assimilation, but only GS is required for regulating GlnR activity. The work not only provides significant insight into understanding the interplay of GlnR and GS in nitrogen metabolism but also provides guidance for improving nitrogen fixation efficiency by modulating nitrogen metabolism.
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Affiliation(s)
- Xiyun Zhao
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yi Song
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Tianshu Wang
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Chongchong Hua
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Rui Hu
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yimin Shang
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Haowen Shi
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
| | - Sanfeng Chen
- Key Laboratory of Soil Microbiology of Agriculture Ministry and College of Biological Sciences, China Agricultural University, Beijing, China
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16
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Wright CL, Lehtovirta-Morley LE. Nitrification and beyond: metabolic versatility of ammonia oxidising archaea. THE ISME JOURNAL 2023; 17:1358-1368. [PMID: 37452095 PMCID: PMC10432482 DOI: 10.1038/s41396-023-01467-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/09/2023] [Accepted: 06/21/2023] [Indexed: 07/18/2023]
Abstract
Ammonia oxidising archaea are among the most abundant living organisms on Earth and key microbial players in the global nitrogen cycle. They carry out oxidation of ammonia to nitrite, and their activity is relevant for both food security and climate change. Since their discovery nearly 20 years ago, major insights have been gained into their nitrogen and carbon metabolism, growth preferences and their mechanisms of adaptation to the environment, as well as their diversity, abundance and activity in the environment. Despite significant strides forward through the cultivation of novel organisms and omics-based approaches, there are still many knowledge gaps on their metabolism and the mechanisms which enable them to adapt to the environment. Ammonia oxidising microorganisms are typically considered metabolically streamlined and highly specialised. Here we review the physiology of ammonia oxidising archaea, with focus on aspects of metabolic versatility and regulation, and discuss these traits in the context of nitrifier ecology.
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Affiliation(s)
- Chloe L Wright
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
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17
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Thompson J, Barr C, Babcock-Adams L, Bird L, La Cava E, Garber A, Hongoh Y, Liu M, Nealson KH, Okamoto A, Repeta D, Suzuki S, Tacto C, Tashjian M, Merino N. Insights into the physiological and genomic characterization of three bacterial isolates from a highly alkaline, terrestrial serpentinizing system. Front Microbiol 2023; 14:1179857. [PMID: 37520355 PMCID: PMC10373932 DOI: 10.3389/fmicb.2023.1179857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/23/2023] [Indexed: 08/01/2023] Open
Abstract
The terrestrial serpentinite-hosted ecosystem known as "The Cedars" is home to a diverse microbial community persisting under highly alkaline (pH ~ 12) and reducing (Eh < -550 mV) conditions. This extreme environment presents particular difficulties for microbial life, and efforts to isolate microorganisms from The Cedars over the past decade have remained challenging. Herein, we report the initial physiological assessment and/or full genomic characterization of three isolates: Paenibacillus sp. Cedars ('Paeni-Cedars'), Alishewanella sp. BS5-314 ('Ali-BS5-314'), and Anaerobacillus sp. CMMVII ('Anaero-CMMVII'). Paeni-Cedars is a Gram-positive, rod-shaped, mesophilic facultative anaerobe that grows between pH 7-10 (minimum pH tested was 7), temperatures 20-40°C, and 0-3% NaCl concentration. The addition of 10-20 mM CaCl2 enhanced growth, and iron reduction was observed in the following order, 2-line ferrihydrite > magnetite > serpentinite ~ chromite ~ hematite. Genome analysis identified genes for flavin-mediated iron reduction and synthesis of a bacillibactin-like, catechol-type siderophore. Ali-BS5-314 is a Gram-negative, rod-shaped, mesophilic, facultative anaerobic alkaliphile that grows between pH 10-12 and temperatures 10-40°C, with limited growth observed 1-5% NaCl. Nitrate is used as a terminal electron acceptor under anaerobic conditions, which was corroborated by genome analysis. The Ali-BS5-314 genome also includes genes for benzoate-like compound metabolism. Anaero-CMMVII remained difficult to cultivate for physiological studies; however, growth was observed between pH 9-12, with the addition of 0.01-1% yeast extract. Anaero-CMMVII is a probable oxygen-tolerant anaerobic alkaliphile with hydrogenotrophic respiration coupled with nitrate reduction, as determined by genome analysis. Based on single-copy genes, ANI, AAI and dDDH analyses, Paeni-Cedars and Ali-BS5-314 are related to other species (P. glucanolyticus and A. aestuarii, respectively), and Anaero-CMMVII represents a new species. The characterization of these three isolates demonstrate the range of ecophysiological adaptations and metabolisms present in serpentinite-hosted ecosystems, including mineral reduction, alkaliphily, and siderophore production.
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Affiliation(s)
- Jaclyn Thompson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Casey Barr
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Lydia Babcock-Adams
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Lina Bird
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC, United States
| | - Eugenio La Cava
- National Institute for Materials Science, Tsukuba, Ibaraki, Japan
| | - Arkadiy Garber
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, United States
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Mark Liu
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Kenneth H. Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Akihiro Okamoto
- Research Center for Macromolecules and Biomaterials, National Institute for Materials Science, Tsukuba, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Japan
| | - Daniel Repeta
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Shino Suzuki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Sagamihara, Kanagawa, Japan
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), JAMSTEC, Yokosuka, Kanagawa, Japan
| | - Clarissa Tacto
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michelle Tashjian
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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18
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Guidotti-Takeuchi M, Melo RTD, Ribeiro LNDM, Dumont CF, Ribeiro RAC, Brum BDA, de Amorim Junior TLIF, Rossi DA. Interference with Bacterial Conjugation and Natural Alternatives to Antibiotics: Bridging a Gap. Antibiotics (Basel) 2023; 12:1127. [PMID: 37508224 PMCID: PMC10376302 DOI: 10.3390/antibiotics12071127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Horizontal gene transfer (HGT) in food matrices has been investigated under conditions that favor gene exchange. However, the major challenge lies in determining the specific conditions pertaining to the adapted microbial pairs associated with the food matrix. HGT is primarily responsible for enhancing the microbial repertoire for the evolution and spread of antimicrobial resistance and is a major target for controlling pathogens of public health concern in food ecosystems. In this study, we investigated Salmonella Heidelberg (SH) and Escherichia coli (EC) regarding gene exchange under conditions mimicking the industrial environment, with the coproducts whey (SL) and chicken juice (CJ). The S. Heidelberg strain was characterized by antibiotic susceptibility standards and PCR to detect the blaTEM gene. A concentration of 0.39 mg/mL was determined to evaluate the anti-conjugation activity of nanostructured lipid nanocarriers (NLCs) of essential oils to mitigate β-lactam resistance gene transfer. The results showed that the addition of these coproducts promoted an increase of more than 3.5 (whey) and 2.5 (chicken juice) orders of magnitude in the conjugation process (p < 0.01), and NLCs of sage essential oil significantly reduced the conjugation frequency (CF) by 74.90, 90.6, and 124.4 times when compared to the transfers in the absence of coproducts and the presence of SL and CJ, respectively. For NLCs from olibanum essential oil, the decrease was 4.46-fold for conjugations without inhibitors and 3.12- and 11.3-fold in the presence of SL and CJ. NLCs associated with sage and olibanum essential oils effectively control the transfer of antibiotic resistance genes and are a promising alternative for use at industrial levels.
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Affiliation(s)
- Micaela Guidotti-Takeuchi
- Laboratory of Molecular Epidemiology, Federal University of Uberlândia, Uberlândia 38402-018, MG, Brazil
| | - Roberta Torres de Melo
- Laboratory of Molecular Epidemiology, Federal University of Uberlândia, Uberlândia 38402-018, MG, Brazil
| | | | - Carolyne Ferreira Dumont
- Laboratory of Molecular Epidemiology, Federal University of Uberlândia, Uberlândia 38402-018, MG, Brazil
| | | | - Bárbara de Araújo Brum
- Laboratory of Molecular Epidemiology, Federal University of Uberlândia, Uberlândia 38402-018, MG, Brazil
| | | | - Daise Aparecida Rossi
- Laboratory of Molecular Epidemiology, Federal University of Uberlândia, Uberlândia 38402-018, MG, Brazil
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19
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Mahlare MJS, Husselmann L, Lewu MN, Bester C, Lewu FB, Caleb OJ. Analysis of the Differentially Expressed Proteins and Metabolic Pathways of Honeybush ( Cyclopia subternata) in Response to Water Deficit Stress. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112181. [PMID: 37299160 DOI: 10.3390/plants12112181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/10/2023] [Accepted: 05/13/2023] [Indexed: 06/12/2023]
Abstract
Honeybush (Cyclopia spp.) is a rich source of antioxidant properties and phenolic compounds. Water availability plays a crucial role in plant metabolic processes, and it contributes to overall quality. Thus, this study aimed to investigate changes in molecular functions, cellular components, and biological processes of Cyclopia subternata exposed to different water stress conditions, which include well-watered (as Control, T1), semi-water stressed (T2), and water-deprived (T3) potted plants. Samples were also collected from a well-watered commercial farm first cultivated in 2013 (T13) and then cultivated in 2017 (T17) and 2019 (T19). Differentially expressed proteins extracted from C. subternata leaves were identified using LC-MS/MS spectrometry. A total of 11 differentially expressed proteins (DEPs) were identified using Fisher's exact test (p < 0.00100). Only α-glucan phosphorylase was found to be statistically common between T17 and T19 (p < 0.00100). Notably, α-glucan phosphorylase was upregulated in the older vegetation (T17) and downregulated in T19 by 1.41-fold. This result suggests that α-glucan phosphorylase was needed in T17 to support the metabolic pathway. In T19, five DEPs were upregulated, while the other six were downregulated. Based on gene ontology, the DEPs in the stressed plant were associated with cellular and metabolic processes, response to stimulus, binding, catalytic activity, and cellular anatomical entity. Differentially expressed proteins were clustered based on the Kyoto Encyclopedia of Genes and Genomes (KEGG), and sequences were linked to metabolic pathways via enzyme code and KEGG ortholog. Most proteins were involved in photosynthesis, phenylpropanoid biosynthesis, thiamine, and purine metabolism. This study revealed the presence of trans-cinnamate 4-monooxygenase, an intermediate for the biosynthesis of a large number of substances, such as phenylpropanoids and flavonoids.
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Affiliation(s)
- Mary-Jane S Mahlare
- Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa
- Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Wellington Campus, Private Bag X8, Wellington 7654, South Africa
| | - Lizex Husselmann
- Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa
| | - Muinat N Lewu
- Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa
| | - Cecilia Bester
- Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa
| | - Francis B Lewu
- Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Wellington Campus, Private Bag X8, Wellington 7654, South Africa
| | - Oluwafemi James Caleb
- Africa Institute for Postharvest Technology, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
- Department of Horticultural Science, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa
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20
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Chen Y, Lin YCD, Luo Y, Cai X, Qiu P, Cui S, Wang Z, Huang HY, Huang HD. Quantitative model for genome-wide cyclic AMP receptor protein binding site identification and characteristic analysis. Brief Bioinform 2023; 24:7145906. [PMID: 37114659 DOI: 10.1093/bib/bbad138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 04/29/2023] Open
Abstract
Cyclic AMP receptor proteins (CRPs) are important transcription regulators in many species. The prediction of CRP-binding sites was mainly based on position-weighted matrixes (PWMs). Traditional prediction methods only considered known binding motifs, and their ability to discover inflexible binding patterns was limited. Thus, a novel CRP-binding site prediction model called CRPBSFinder was developed in this research, which combined the hidden Markov model, knowledge-based PWMs and structure-based binding affinity matrixes. We trained this model using validated CRP-binding data from Escherichia coli and evaluated it with computational and experimental methods. The result shows that the model not only can provide higher prediction performance than a classic method but also quantitatively indicates the binding affinity of transcription factor binding sites by prediction scores. The prediction result included not only the most knowns regulated genes but also 1089 novel CRP-regulated genes. The major regulatory roles of CRPs were divided into four classes: carbohydrate metabolism, organic acid metabolism, nitrogen compound metabolism and cellular transport. Several novel functions were also discovered, including heterocycle metabolic and response to stimulus. Based on the functional similarity of homologous CRPs, we applied the model to 35 other species. The prediction tool and the prediction results are online and are available at: https://awi.cuhk.edu.cn/∼CRPBSFinder.
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Affiliation(s)
- Yigang Chen
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Yang-Chi-Dung Lin
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Yijun Luo
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Xiaoxuan Cai
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Peng Qiu
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Shidong Cui
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Zhe Wang
- School of Humanities and Social Science, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Hsi-Yuan Huang
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
| | - Hsien-Da Huang
- School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
- Warshel Institute for Computational Biology, School of Medicine, Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China
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21
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Jiang M, Zhao D, Huang L, Zeng Y, Liu J, Xiang H, Zheng Y. The Role of Glutamine Synthetase in Regulating Ammonium Assimilation and Iron-Only Nitrogenase Expression in a Photosynthetic Diazotroph. Microbiol Spectr 2023:e0495322. [PMID: 36971559 PMCID: PMC10100968 DOI: 10.1128/spectrum.04953-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
The photosynthetic diazotrophs, such as
Rhodopseudomonas palustris
, can utilize light energy to drive the conversion of carbon dioxide (CO
2
) to a much more powerful greenhouse gas methane (CH
4
) by Fe-only nitrogenase, which is strictly regulated in response to the ammonium, a substrate of glutamine synthetase for the biosynthesis of glutamine. However, the primary glutamine synthetase for ammonium assimilation and its role in nitrogenase regulation remain unclear in
R. palustris
.
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22
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Martin Del Campo JS, Rigsbee J, Bueno Batista M, Mus F, Rubio LM, Einsle O, Peters JW, Dixon R, Dean DR, Dos Santos PC. Overview of physiological, biochemical, and regulatory aspects of nitrogen fixation in Azotobacter vinelandii. Crit Rev Biochem Mol Biol 2023; 57:492-538. [PMID: 36877487 DOI: 10.1080/10409238.2023.2181309] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Understanding how Nature accomplishes the reduction of inert nitrogen gas to form metabolically tractable ammonia at ambient temperature and pressure has challenged scientists for more than a century. Such an understanding is a key aspect toward accomplishing the transfer of the genetic determinants of biological nitrogen fixation to crop plants as well as for the development of improved synthetic catalysts based on the biological mechanism. Over the past 30 years, the free-living nitrogen-fixing bacterium Azotobacter vinelandii emerged as a preferred model organism for mechanistic, structural, genetic, and physiological studies aimed at understanding biological nitrogen fixation. This review provides a contemporary overview of these studies and places them within the context of their historical development.
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Affiliation(s)
| | - Jack Rigsbee
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | | | - Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Luis M Rubio
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Pozuelo de Alarcón, Spain
| | - Oliver Einsle
- Department of Biochemistry, University of Freiburg, Freiburg, Germany
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Dennis R Dean
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
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23
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The Roles of Nicotinamide Adenine Dinucleotide Phosphate Reoxidation and Ammonium Assimilation in the Secretion of Amino Acids as Byproducts of Clostridium thermocellum. Appl Environ Microbiol 2023; 89:e0175322. [PMID: 36625594 PMCID: PMC9888227 DOI: 10.1128/aem.01753-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Clostridium thermocellum is a cellulolytic thermophile that is considered for the consolidated bioprocessing of lignocellulose to ethanol. Improvements in ethanol yield are required for industrial implementation, but the incompletely understood causes of amino acid secretion impede progress. In this study, amino acid secretion was investigated via gene deletions in ammonium-regulated, nicotinamide adenine dinucleotide phosphate (NADPH)-supplying and NADPH-consuming pathways as well as via physiological characterization in cellobiose-limited or ammonium-limited chemostats. First, the contribution of the NADPH-supplying malate shunt was studied with strains using either the NADPH-yielding malate shunt (Δppdk) or a redox-independent conversion of PEP to pyruvate (Δppdk ΔmalE::Peno-pyk). In the latter, branched-chain amino acids, especially valine, were significantly reduced, whereas the ethanol yield increased from 46 to 60%, suggesting that the secretion of these amino acids balances the NADPH surplus from the malate shunt. The unchanged amino acid secretion in Δppdk falsified a previous hypothesis on an ammonium-regulated PEP-to-pyruvate flux redistribution. The possible involvement of another NADPH-supplier, namely, NADH-dependent reduced ferredoxin:NADP+ oxidoreductase (nfnAB), was also excluded. Finally, the deletion of glutamate synthase (gogat) in ammonium assimilation resulted in the upregulation of NADPH-linked glutamate dehydrogenase activity and decreased amino acid yields. Since gogat in C. thermocellum is putatively annotated as ferredoxin-linked, a claim which is supported by the product redistribution observed in this study, this deletion likely replaced ferredoxin with NADPH in ammonium assimilation. Overall, these findings indicate that a need to reoxidize NADPH is driving the observed amino acid secretion, likely at the expense of the NADH needed for ethanol formation. This suggests that metabolic engineering strategies that simplify the redox metabolism and ammonium assimilation can contribute to increased ethanol yields. IMPORTANCE Improving the ethanol yield of C. thermocellum is important for the industrial implementation of this microorganism in consolidated bioprocessing. A central role of NADPH in driving amino acid byproduct formation was demonstrated by eliminating the NADPH-supplying malate shunt and separately by changing the cofactor specificity in ammonium assimilation. With amino acid secretion diverting carbon and electrons away from ethanol, these insights are important for further metabolic engineering to reach industrial requirements on ethanol yield. This study also provides chemostat data that are relevant for training genome-scale metabolic models and for improving the validity of their predictions, especially considering the reduced degree-of-freedom in the redox metabolism of the strains generated here. In addition, this study advances the fundamental understanding on the mechanisms underlying amino acid secretion in cellulolytic Clostridia as well as on the regulation and cofactor specificity in ammonium assimilation. Together, these efforts aid in the development of C. thermocellum for the sustainable consolidated bioprocessing of lignocellulose to ethanol with minimal pretreatment.
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24
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Qi Z, Gao A, Li L, Li Z, Zhang W, Dong S, Liu X. A novel strategy to improving Rhodobacter azotoformans denitrification efficiency: Insight into the role of a two-component system NtrX/Y in denitrification regulation. BIORESOURCE TECHNOLOGY 2023; 368:128349. [PMID: 36400277 DOI: 10.1016/j.biortech.2022.128349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
Transcription factors (TFs) can manage the coordinated expression of genes clusters or multiple genes. TF was used to improve bacterial denitrification ability in this study. During denitrification, the ntrY of R. azotoformans, which encodes the sensor of NtrX/Y system, was significantly upregulated in transcription. Denitrification of the mutant △ntrY was significantly inhibited, and it was recovered after replenishing this gene to the mutant, which indicates the NtrX/Y system plays an important role in regulating bacterial denitrification. According to additional research, the NtrX/Y system regulates bacterial denitrification by directly promoting the expression of the nitrite reductase. ntrY overexpression appears to accelerate bacterial denitrification, and the introduction of a strong promoter tac in conjunction with iron supply optimization increases the rate by 72% further. This study realizes bacterial denitrification enhancement from the perspective of global transcription regulation, which provides a novel strategy for improving microbial ability to degrade pollutants.
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Affiliation(s)
- Zhengliang Qi
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China.
| | - Anxin Gao
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Lu Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Zhen Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Wenyue Zhang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Shuhan Dong
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Xinli Liu
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
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25
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Li Q, Zhang H, Song Y, Wang M, Hua C, Li Y, Chen S, Dixon R, Li J. Alanine synthesized by alanine dehydrogenase enables ammonium-tolerant nitrogen fixation in Paenibacillus sabinae T27. Proc Natl Acad Sci U S A 2022; 119:e2215855119. [PMID: 36459643 PMCID: PMC9894248 DOI: 10.1073/pnas.2215855119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/08/2022] [Indexed: 12/04/2022] Open
Abstract
Most diazotrophs fix nitrogen only under nitrogen-limiting conditions, for example, in the presence of relatively low concentrations of NH4+ (0 to 2 mM). However, Paenibacillus sabinae T27 exhibits an unusual pattern of nitrogen regulation of nitrogen fixation, since although nitrogenase activities are high under nitrogen-limiting conditions (0 to 3 mM NH4+) and are repressed under conditions of nitrogen sufficiency (4 to 30 mM NH4+), nitrogenase activity is reestablished when very high levels of NH4+ (30 to 300 mM) are present in the medium. To further understand this pattern of nitrogen fixation regulation, we carried out transcriptome analyses of P. sabinae T27 in response to increasing ammonium concentrations. As anticipated, the nif genes were highly expressed, either in the absence of fixed nitrogen or in the presence of a high concentration of NH4+ (100 mM), but were subject to negative feedback regulation at an intermediate concentration of NH4+ (10 mM). Among the differentially expressed genes, ald1, encoding alanine dehydrogenase (ADH1), was highly expressed in the presence of a high level of NH4+ (100 mM). Mutation and complementation experiments revealed that ald1 is required for nitrogen fixation at high ammonium concentrations. We demonstrate that alanine, synthesized by ADH1 from pyruvate and NH4+, inhibits GS activity, leading to a low intracellular glutamine concentration that prevents feedback inhibition of GS and mimics nitrogen limitation, enabling activation of nif transcription by the nitrogen-responsive regulator GlnR in the presence of high levels of extracellular ammonium.
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Affiliation(s)
- Qin Li
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Haowei Zhang
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Yi Song
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Minyang Wang
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Chongchong Hua
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Yashi Li
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Sanfeng Chen
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, United Kingdom
| | - Jilun Li
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing100193, People’s Republic of China
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26
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Han F, Zhou W. Nitrogen recovery from wastewater by microbial assimilation - A review. BIORESOURCE TECHNOLOGY 2022; 363:127933. [PMID: 36100188 DOI: 10.1016/j.biortech.2022.127933] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
The increased nitrogen (N) input with low utilization rate in artificial N management has led to massive reactive N (Nr) flows, putting the Earth in a high-risk state. It is essential to recover and recycle Nr during or after Nr removal from wastewater to reduce N input while simultaneously mitigate Nr pollution in addressing the N stress. However, mechanisms for efficient Nr recovery during or after Nr removal remain unclear. Here, the occurrence of N risk and progress in wastewater treatment in recent years as well as challenges of the current technologies for N recovery from wastewater were reviewed. Through analyzing N conversion fluxes in biogeochemical N-cycling networks, microbial N assimilation through photosynthetic and heterotrophic microorganisms was highlighted as promising alternative for synergistic N removal and recovery in wastewater treatment. In addition, the prospects and gaps of Nr recovery from wastewater through microbial assimilation are discussed.
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Affiliation(s)
- Fei Han
- School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266000, China
| | - Weizhi Zhou
- School of Civil Engineering, Shandong University, Jinan, Shandong 250002, China.
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27
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Huang X, Luo Y, Luo L, Xie D, Li Z. The nitrite reductase encoded by nirBDs in Pseudomonas putida Y-9 influences ammonium transformation. Front Microbiol 2022; 13:982674. [PMID: 36312953 PMCID: PMC9597696 DOI: 10.3389/fmicb.2022.982674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/21/2022] [Indexed: 09/13/2023] Open
Abstract
It is unknown whether nirBDs, which conventionally encode an NADH nitrite reductase, play other novel roles in nitrogen cycling. In this study, we explored the role of nirBDs in the nitrogen cycling of Pseudomonas putida Y-9. nirBDs had no effect on organic nitrogen transformation by strain Y-9. The △nirBD strain exhibited higher ammonium removal efficiency (90.7%) than the wild-type strain (76.1%; P < 0.05) and lower end gaseous nitrogen (N2O) production. Moreover, the expression of glnA (control of the ammonium assimilation) in the △nirBD strain was higher than that in the wild-type strain (P < 0.05) after being cultured in ammonium-containing medium. Furthermore, nitrite noticeably inhibited the ammonium elimination of the wild-type strain, with a corresponding removal rate decreasing to 44.8%. However, no similar impact on ammonium transformation was observed for the △nirBD strain, with removal efficiency reaching 97.5%. In conclusion, nirBDs in strain Y-9 decreased the ammonium assimilation and increased the ammonium oxidation to nitrous oxide.
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Affiliation(s)
- Xuejiao Huang
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
- Guangxi Bossco Environmental Protection Technology Co., Ltd., Nanning, China
| | - Yuwen Luo
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
| | - Luo Luo
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
| | - Deti Xie
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
| | - Zhenlun Li
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
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28
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Walling LR, Kouse AB, Shabalina SA, Zhang H, Storz G. A 3' UTR-derived small RNA connecting nitrogen and carbon metabolism in enteric bacteria. Nucleic Acids Res 2022; 50:10093-10109. [PMID: 36062564 DOI: 10.1093/nar/gkac748] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/11/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Increasing numbers of small, regulatory RNAs (sRNAs) corresponding to 3' untranslated regions (UTR) are being discovered in bacteria. One such sRNA, denoted GlnZ, corresponds to the 3' UTR of the Escherichia coli glnA mRNA encoding glutamine synthetase. Several forms of GlnZ, processed from the glnA mRNA, are detected in cells growing with limiting ammonium. GlnZ levels are regulated transcriptionally by the NtrC transcription factor and post-transcriptionally by RNase III. Consistent with the expression, E. coli cells lacking glnZ show delayed outgrowth from nitrogen starvation compared to wild type cells. Transcriptome-wide RNA-RNA interactome datasets indicated that GlnZ binds to multiple target RNAs. Immunoblots and assays of fusions confirmed GlnZ-mediated repression of glnP and sucA, encoding proteins that contribute to glutamine transport and the citric acid cycle, respectively. Although the overall sequences of GlnZ from E. coli K-12, Enterohemorrhagic E. coli and Salmonella enterica have significant differences due to various sequence insertions, all forms of the sRNA were able to regulate the two targets characterized. Together our data show that GlnZ impacts growth of E. coli under low nitrogen conditions by modulating genes that affect carbon and nitrogen flux.
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Affiliation(s)
- Lauren R Walling
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Andrew B Kouse
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Hongen Zhang
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-4417, USA
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29
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Matsumoto T, Hiramoto S, Niwa T, Machida H, Suto C, Takahashi M. First description of a clinical glutamine-dependent Escherichia coli with a missense mutation in the glnA. J Infect Chemother 2022; 28:1513-1518. [DOI: 10.1016/j.jiac.2022.07.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/13/2022] [Accepted: 07/28/2022] [Indexed: 10/31/2022]
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30
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Koper K, Han SW, Pastor DC, Yoshikuni Y, Maeda HA. Evolutionary Origin and Functional Diversification of Aminotransferases. J Biol Chem 2022; 298:102122. [PMID: 35697072 PMCID: PMC9309667 DOI: 10.1016/j.jbc.2022.102122] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/30/2022] Open
Abstract
Aminotransferases (ATs) are pyridoxal 5′-phosphate–dependent enzymes that catalyze the transamination reactions between amino acid donor and keto acid acceptor substrates. Modern AT enzymes constitute ∼2% of all classified enzymatic activities, play central roles in nitrogen metabolism, and generate multitude of primary and secondary metabolites. ATs likely diverged into four distinct AT classes before the appearance of the last universal common ancestor and further expanded to a large and diverse enzyme family. Although the AT family underwent an extensive functional specialization, many AT enzymes retained considerable substrate promiscuity and multifunctionality because of their inherent mechanistic, structural, and functional constraints. This review summarizes the evolutionary history, diverse metabolic roles, reaction mechanisms, and structure–function relationships of the AT family enzymes, with a special emphasis on their substrate promiscuity and multifunctionality. Comprehensive characterization of AT substrate specificity is still needed to reveal their true metabolic functions in interconnecting various branches of the nitrogen metabolic network in different organisms.
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Affiliation(s)
- Kaan Koper
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Sang-Woo Han
- The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Yasuo Yoshikuni
- The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Global Center for Food, Land, and Water Resources, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Hiroshi A Maeda
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
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Liao HS, Chung YH, Hsieh MH. Glutamate: A multifunctional amino acid in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 318:111238. [PMID: 35351313 DOI: 10.1016/j.plantsci.2022.111238] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Glutamate (Glu) is a versatile metabolite and a signaling molecule in plants. Glu biosynthesis is associated with the primary nitrogen assimilation pathway. The conversion between Glu and 2-oxoglutarate connects Glu metabolism to the tricarboxylic acid cycle, carbon metabolism, and energy production. Glu is the predominant amino donor for transamination reactions in the cell. In addition to protein synthesis, Glu is a building block for tetrapyrroles, glutathione, and folate. Glu is the precursor of γ-aminobutyric acid that plays an important role in balancing carbon/nitrogen metabolism and various cellular processes. Glu can conjugate to the major auxin indole 3-acetic acid (IAA), and IAA-Glu is destined for oxidative degradation. Glu also conjugates with isochorismate for the production of salicylic acid. Accumulating evidence indicates that Glu functions as a signaling molecule to regulate plant growth, development, and defense responses. The ligand-gated Glu receptor-like proteins (GLRs) mediate some of these responses. However, many of the Glu signaling events are GLR-independent. The receptor perceiving extracellular Glu as a danger signal is still unknown. In addition to GLRs, Glu may act on receptor-like kinases or receptor-like proteins to trigger immune responses. Glu metabolism and Glu signaling may entwine to regulate growth, development, and defense responses in plants.
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Affiliation(s)
- Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Hsin Chung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
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Huang P, Chen S, Chiang W, Ho M, Wu K. Structural basis for the helical filament formation of
Escherichia coli
glutamine synthetase. Protein Sci 2022; 31:e4304. [PMID: 35481643 PMCID: PMC8996467 DOI: 10.1002/pro.4304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/01/2023]
Abstract
Escherichia coli glutamine synthetase (EcGS) spontaneously forms a dodecamer that catalytically converts glutamate to glutamine. EcGS stacks with other dodecamers to create a filament-like polymer visible under transmission electron microscopy. Filamentous EcGS is induced by environmental metal ions. We used cryo-electron microscopy (cryo-EM) to decipher the structure of metal ion (nickel)-induced EcGS helical filament at a sub-3Å resolution. EcGS filament formation involves stacking of native dodecamers by chelating nickel ions to residues His5 and His13 in the first N-terminal helix (H1). His5 and His13 from paired parallel H1 helices provide salt bridges and hydrogen bonds to tightly stack two dodecamers. One subunit of the EcGS filament hosts two nickel ions, whereas the dodecameric interface and the ATP/Mg-binding site both host a nickel ion each. We reveal that upon adding glutamate or ATP for catalytic reactions, nickel-induced EcGS filament reverts to individual dodecamers. Such tunable filament formation is often associated with stress responses. Our results provide detailed structural information on the mechanism underlying reversible and tunable EcGS filament formation.
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Affiliation(s)
- Pei‐Chi Huang
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan Normal University Taipei Taiwan
| | - Shao‐Kang Chen
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
| | - Wei‐Hung Chiang
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
| | - Meng‐Ru Ho
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
| | - Kuen‐Phon Wu
- Institute of Biological Chemistry Academia Sinica Taipei Taiwan
- Institute of Biochemical Science College of Life Science, National Taiwan University Taipei Taiwan
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Bowlin MQ, Long AR, Huffines JT, Gray MJ. The role of nitrogen-responsive regulators in controlling inorganic polyphosphate synthesis in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001185. [PMID: 35482529 PMCID: PMC10233264 DOI: 10.1099/mic.0.001185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/10/2022] [Indexed: 12/22/2022]
Abstract
Inorganic polyphosphate (polyP) is synthesized by bacteria under stressful environmental conditions and acts by a variety of mechanisms to promote cell survival. While the kinase that synthesizes polyP (PPK, encoded by the ppk gene) is well known, ppk transcription is not activated by environmental stress and little is understood about how environmental stress signals lead to polyP accumulation. Previous work has shown that the transcriptional regulators DksA, RpoN (σ54) and RpoE (σ24) positively regulate polyP production, but not ppk transcription, in Escherichia coli. In this work, we examine the role of the alternative sigma factor RpoN and nitrogen starvation stress response pathways in controlling polyP synthesis. We show that the RpoN enhancer binding proteins GlnG and GlrR impact polyP production, and uncover a new role for the nitrogen phosphotransferase regulator PtsN (EIIANtr) as a positive regulator of polyP production, acting upstream of DksA, downstream of RpoN and apparently independently of RpoE. However, neither these regulatory proteins nor common nitrogen metabolites appear to act directly on PPK, and the precise mechanism(s) by which polyP production is modulated after stress remain(s) unclear. Unexpectedly, we also found that the genes that impact polyP production vary depending on the composition of the rich media in which the cells were grown before exposure to polyP-inducing stress. These results constitute progress towards deciphering the regulatory networks driving polyP production under stress, and highlight the remarkable complexity of this regulation and its connections to a broad range of stress-sensing pathways.
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Affiliation(s)
- Marvin Q. Bowlin
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Abagail Renee Long
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Joshua T. Huffines
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Michael Jeffrey Gray
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Femerling G, Gama-Castro S, Lara P, Ledezma-Tejeida D, Tierrafría VH, Muñiz-Rascado L, Bonavides-Martínez C, Collado-Vides J. Sensory Systems and Transcriptional Regulation in Escherichia coli. Front Bioeng Biotechnol 2022; 10:823240. [PMID: 35237580 PMCID: PMC8882922 DOI: 10.3389/fbioe.2022.823240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
In free-living bacteria, the ability to regulate gene expression is at the core of adapting and interacting with the environment. For these systems to have a logic, a signal must trigger a genetic change that helps the cell to deal with what implies its presence in the environment; briefly, the response is expected to include a feedback to the signal. Thus, it makes sense to think of genetic sensory mechanisms of gene regulation. Escherichia coli K-12 is the bacterium model for which the largest number of regulatory systems and its sensing capabilities have been studied in detail at the molecular level. In this special issue focused on biomolecular sensing systems, we offer an overview of the transcriptional regulatory corpus of knowledge for E. coli that has been gathered in our database, RegulonDB, from the perspective of sensing regulatory systems. Thus, we start with the beginning of the information flux, which is the signal’s chemical or physical elements detected by the cell as changes in the environment; these signals are internally transduced to transcription factors and alter their conformation. Signals transduced to effectors bind allosterically to transcription factors, and this defines the dominant sensing mechanism in E. coli. We offer an updated list of the repertoire of known allosteric effectors, as well as a list of the currently known different mechanisms of this sensing capability. Our previous definition of elementary genetic sensory-response units, GENSOR units for short, that integrate signals, transport, gene regulation, and the biochemical response of the regulated gene products of a given transcriptional factor fit perfectly with the purpose of this overview. We summarize the functional heterogeneity of their response, based on our updated collection of GENSORs, and we use them to identify the expected feedback as part of their response. Finally, we address the question of multiple sensing in the regulatory network of E. coli. This overview introduces the architecture of sensing and regulation of native components in E.coli K-12, which might be a source of inspiration to bioengineering applications.
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Affiliation(s)
- Georgette Femerling
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Socorro Gama-Castro
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Paloma Lara
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Víctor H. Tierrafría
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Luis Muñiz-Rascado
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Julio Collado-Vides
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- *Correspondence: Julio Collado-Vides,
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35
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Li Z, Li L, Sun H, Wang W, Yang Y, Qi Z, Liu X. Ammonia assimilation: A double-edged sword influencing denitrification of Rhodobacter azotoformans and for nitrogen removal of aquaculture wastewater. BIORESOURCE TECHNOLOGY 2022; 345:126495. [PMID: 34883195 DOI: 10.1016/j.biortech.2021.126495] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
NO3--N and NH4+-N are two prevalent nitrogenous pollutants in aquaculture wastewater posing a significant health risk to aquatic animals. R. azotoformans ATCC17025 can rapidly denitrify to remove NO3--N, assimilating NH4+-N. The study investigated the influence of ammonia assimilation on bacterial denitrification. Results revealed that low concentration of NH4+-N (≤0.3 mM) accelerated denitrification, whereas high concentration inhibited it. RT-qPCR indicated that the inhibition of NO reduction under high concentration of NH4+-N was the primary cause of denitrification depression, whereas low concentration of NH4+-N enhanced the synthesis of practically all enzymes involved in denitrification. Finally, nitrogen-rich aquaculture effluent was effectively treated in lab-scale using a semi-continuous operation that provided an appropriate NH4+-N concentration for denitrification. This semi-continuous operation treated wastewater 2 times faster than the batch operation and the content of nitrogen decreased to effluent standard. The study can provide guidance for nitrogen removal of aquaculture wastewater with bioaugmentation.
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Affiliation(s)
- Zhen Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Lu Li
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Haoyu Sun
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Wenjuan Wang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Yuying Yang
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
| | - Zhengliang Qi
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China.
| | - Xinli Liu
- Key Laboratory of Shandong Microbial Engineering, College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China; State Key Laboratory of Bio-based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, PR China
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36
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C4-dicarboxylates as growth substrates and signaling molecules for commensal and pathogenic enteric bacteria in mammalian intestine. J Bacteriol 2022; 204:e0054521. [PMID: 34978458 DOI: 10.1128/jb.00545-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The C4-dicarboxylates (C4-DC) L-aspartate and L-malate have been identified as playing an important role in the colonization of mammalian intestine by enteric bacteria, such as Escherichia coli and Salmonella Typhimurium, and succinate as a signaling molecule for host-enteric bacteria interaction. Thus, endogenous and exogenous fumarate respiration and related functions are required for efficient initial growth of the bacteria. L-aspartate represents a major substrate for fumarate respiration in the intestine and a high-quality substrate for nitrogen assimilation. During nitrogen assimilation, DcuA catalyzes an L-aspartate/fumarate antiport and serves as a nitrogen shuttle for the net uptake of ammonium only, whereas DcuB acts as a redox shuttle that catalyzes the L-malate/succinate antiport during fumarate respiration. The C4-DC two-component system DcuS-DcuR is active in the intestine and responds to intestinal C4-DC levels. Moreover, in macrophages and in mice, succinate is a signal that promotes virulence and survival of S. Tm and pathogenic E. coli. On the other hand, intestinal succinate is an important signaling molecule for the host and activates response and protective programs. Therefore, C4-DCs play a major role in supporting colonization of enteric bacteria and as signaling molecules for the adaptation of host physiology.
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37
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Miyakoshi M, Morita T, Kobayashi A, Berger A, Takahashi H, Gotoh Y, Hayashi T, Tanaka K. Glutamine synthetase mRNA releases sRNA from its 3'UTR to regulate carbon/nitrogen metabolic balance in Enterobacteriaceae. eLife 2022; 11:82411. [PMID: 36440827 PMCID: PMC9731577 DOI: 10.7554/elife.82411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/27/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamine synthetase (GS) is the key enzyme of nitrogen assimilation induced under nitrogen limiting conditions. The carbon skeleton of glutamate and glutamine, 2-oxoglutarate, is supplied from the TCA cycle, but how this metabolic flow is controlled in response to nitrogen availability remains unknown. We show that the expression of the E1o component of 2-oxoglutarate dehydrogenase, SucA, is repressed under nitrogen limitation in Salmonella enterica and Escherichia coli. The repression is exerted at the post-transcriptional level by an Hfq-dependent sRNA GlnZ generated from the 3'UTR of the GS-encoding glnA mRNA. Enterobacterial GlnZ variants contain a conserved seed sequence and primarily regulate sucA through base-pairing far upstream of the translation initiation region. During growth on glutamine as the nitrogen source, the glnA 3'UTR deletion mutants expressed SucA at higher levels than the S. enterica and E. coli wild-type strains, respectively. In E. coli, the transcriptional regulator Nac also participates in the repression of sucA. Lastly, this study clarifies that the release of GlnZ from the glnA mRNA by RNase E is essential for the post-transcriptional regulation of sucA. Thus, the mRNA coordinates the two independent functions to balance the supply and demand of the fundamental metabolites.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Infection Biology, Faculty of Medicine, University of TsukubaTsukubaJapan,Transborder Medical Research Center, University of TsukubaTsukubaJapan,International Joint Degree Master’s Program in Agro-Biomedical Science in Food and Health (GIP-TRIAD), University of TsukubaTsukubaJapan
| | - Teppei Morita
- Institute for Advanced Biosciences, Keio UniversityTsuruokaJapan,Graduate School of Media and Governance, Keio UniversityFujisawaJapan
| | - Asaki Kobayashi
- Transborder Medical Research Center, University of TsukubaTsukubaJapan
| | - Anna Berger
- International Joint Degree Master’s Program in Agro-Biomedical Science in Food and Health (GIP-TRIAD), University of TsukubaTsukubaJapan
| | | | - Yasuhiro Gotoh
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu UniversityFukuokaJapan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu UniversityFukuokaJapan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of TechnologyYokohamaJapan
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Martien JI, Trujillo EA, Jacobson TB, Tatli M, Hebert AS, Stevenson DM, Coon JJ, Amador-Noguez D. Metabolic Remodeling during Nitrogen Fixation in Zymomonas mobilis. mSystems 2021; 6:e0098721. [PMID: 34783580 PMCID: PMC8594446 DOI: 10.1128/msystems.00987-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/06/2021] [Indexed: 11/20/2022] Open
Abstract
Zymomonas mobilis is an ethanologenic bacterium currently being developed for production of advanced biofuels. Recent studies have shown that Z. mobilis can fix dinitrogen gas (N2) as a sole nitrogen source. During N2 fixation, Z. mobilis exhibits increased biomass-specific rates of ethanol production. In order to better understand the physiology of Z. mobilis during N2 fixation and during changes in ammonium (NH4+) availability, we performed liquid chromatography-mass spectrometry (LC-MS)-based targeted metabolomics and shotgun proteomics under three regimes of nitrogen availability: continuous N2 fixation, gradual NH4+ depletion, and acute NH4+ addition to N2-fixing cells. We report dynamic changes in abundance of proteins and metabolites related to nitrogen fixation, motility, ammonium assimilation, amino acid biosynthesis, nucleotide biosynthesis, isoprenoid biosynthesis, and Entner-Doudoroff (ED) glycolysis, providing insight into the regulatory mechanisms that control these processes in Z. mobilis. Our analysis identified potential physiological mechanisms that may contribute to increased specific ethanol production during N2 fixation, including decreased activity of biosynthetic pathways, increased protein abundance of alcohol dehydrogenase (ADHI), and increased thermodynamic favorability of the ED pathway. Of particular relevance to advanced biofuel production, we found that intermediates in the methylerythritol phosphate (MEP) pathway for isoprenoid biosynthesis were depleted during N2 fixation, coinciding with decreased protein abundance of deoxyxylulose 5-phosphate synthase (DXS), the first enzyme in the pathway. This implies that DXS protein abundance serves as a native control point in regulating MEP pathway activity in Z. mobilis. The results of this study will inform metabolic engineering to further develop Z. mobilis as a platform organism for biofuel production. IMPORTANCE Biofuels and bioproducts have the potential to serve as environmentally sustainable replacements for petroleum-derived fuels and commodity molecules. Advanced fuels such as higher alcohols and isoprenoids are more suitable gasoline replacements than bioethanol. Developing microbial systems to generate advanced biofuels requires metabolic engineering to reroute carbon away from ethanol and other native products and toward desired pathways, such as the MEP pathway for isoprenoid biosynthesis. However, rational engineering of microbial metabolism relies on understanding metabolic control points, in terms of both enzyme activity and thermodynamic favorability. In Z. mobilis, the factors that control glycolytic rates, ethanol production, and isoprenoid production are still not fully understood. In this study, we performed metabolomic, proteomic, and thermodynamic analysis of Z. mobilis during N2 fixation. This analysis identified key changes in metabolite levels, enzyme abundance, and glycolytic thermodynamic favorability that occurred during changes in NH4+ availability, helping to inform future efforts in metabolic engineering.
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Affiliation(s)
- Julia I. Martien
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Edna A. Trujillo
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Tyler B. Jacobson
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Mehmet Tatli
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Alexander S. Hebert
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - David M. Stevenson
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Joshua J. Coon
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Biomolecular Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Daniel Amador-Noguez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
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Jacob C, Velásquez AC, Josh NA, Settles M, He SY, Melotto M. Dual transcriptomic analysis reveals metabolic changes associated with differential persistence of human pathogenic bacteria in leaves of Arabidopsis and lettuce. G3 (BETHESDA, MD.) 2021; 11:jkab331. [PMID: 34550367 PMCID: PMC8664426 DOI: 10.1093/g3journal/jkab331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/09/2021] [Indexed: 11/14/2022]
Abstract
Understanding the molecular determinants underlying the interaction between the leaf and human pathogenic bacteria is key to provide the foundation to develop science-based strategies to prevent or decrease the pathogen contamination of leafy greens. In this study, we conducted a dual RNA-sequencing analysis to simultaneously define changes in the transcriptomic profiles of the plant and the bacterium when they come in contact. We used an economically relevant vegetable crop, lettuce (Lactuca sativa L. cultivar Salinas), and a model plant, Arabidopsis thaliana Col-0, as well as two pathogenic bacterial strains that cause disease outbreaks associated with fresh produce, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium 14028s (STm 14028s). We observed commonalities and specificities in the modulation of biological processes between Arabidopsis and lettuce and between O157:H7 and STm 14028s during early stages of the interaction. We detected a larger alteration of gene expression at the whole transcriptome level in lettuce and Arabidopsis at 24 h post inoculation with STm 14028s compared to that with O157:H7. In addition, bacterial transcriptomic adjustments were substantially larger in Arabidopsis than in lettuce. Bacterial transcriptome was affected at a larger extent in the first 4 h compared to the subsequent 20 h after inoculation. Overall, we gained valuable knowledge about the responses and counter-responses of both bacterial pathogen and plant host when these bacteria are residing in the leaf intercellular space. These findings and the public genomic resources generated in this study are valuable for additional data mining.
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Affiliation(s)
- Cristián Jacob
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
- Department of Plant Sciences, Horticulture and Agronomy Graduate Group, University of California, Davis, Davis, CA 95616, USA
- Departamento de Ciencias Vegetales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - André C Velásquez
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | - Nikhil A Josh
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Matthew Settles
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Sheng Yang He
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
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Zhang M, Han F, Li Y, Liu Z, Chen H, Li Z, Li Q, Zhou W. Nitrogen recovery by a halophilic ammonium-assimilating microbiome: A new strategy for saline wastewater treatment. WATER RESEARCH 2021; 207:117832. [PMID: 34781183 DOI: 10.1016/j.watres.2021.117832] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/15/2021] [Accepted: 10/31/2021] [Indexed: 05/12/2023]
Abstract
Wastewater with high salinity is one of the major challenges for conventional wastewater treatment. Although nitrogen management is vital for wastewater treatment, efficient strategies for nitrogen recovery and removal from saline wastewater remain challenging. Here we propose microbial ammonium assimilation to achieve efficient nitrogen removal and recovery into biomass from saline wastewater without gaseous nitrogen release opposite to the conventional wastewater treatment, . We find one marine bacterium Psychrobacter aquimaris A4N01 with the ability to form sedimentary granular biofilms that can be engineered to construct an efficient ammonium-assimilating microbiome followed the bottom-up design. We demonstrate that the microbiome removes ammonium through assimilation without reactive nitrogen intermediates and gaseous nitrogen emission, according to the functional gene abundance and nitrogen balance. More than 80% of ammonium, total nitrogen and total phosphorus are removed and recovered into biomass, with more than 98% of COD removed from saline wastewater. As one prototypic microbe to form ammonium-assimilating biofilms, Psychrobacter aquimaris A4N01 plays key role in nutrient metabolism and microbiome construction. We stress that ammonium assimilation with a clear and short pathway is a promising method in future saline wastewater treatment and sustainable nitrogen management.
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Affiliation(s)
- Mengru Zhang
- School of Environmental Science and Engineering, Shandong University, 250100 Jinan, China
| | - Fei Han
- School of Environmental Science and Engineering, Shandong University, 250100 Jinan, China
| | - Yuke Li
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| | - Zhe Liu
- School of Environmental Science and Engineering, Shandong University, 250100 Jinan, China
| | - Hao Chen
- School of Environmental Science and Engineering, Shandong University, 250100 Jinan, China
| | - Zhe Li
- School of Civil Engineering, Shandong University, 250061 Jinan, China
| | - Qian Li
- School of Environmental Science and Engineering, Shandong University, 250100 Jinan, China
| | - Weizhi Zhou
- School of Civil Engineering, Shandong University, 250061 Jinan, China.
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41
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Jatuponwiphat T, Namrak T, Nitisinprasert S, Nakphaichit M, Vongsangnak W. Integrative growth physiology and transcriptome profiling of probiotic Limosilactobacillus reuteri KUB-AC5. PeerJ 2021; 9:e12226. [PMID: 34707932 PMCID: PMC8500091 DOI: 10.7717/peerj.12226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/08/2021] [Indexed: 12/26/2022] Open
Abstract
Limosilactobacillus reuteri KUB-AC5 has been widely used as probiotic in chicken for Salmonella reduction. However, a preferable carbon source and growth phase is poorly characterized underlying metabolic responses on growth and inhibition effects of L. reuteri KUB-AC5. This study therefore aimed to investigate transcriptome profiling of L. reuteri KUB-AC5 revealing global metabolic responses when alteration of carbon sources and growth phases. Interestingly, L. reuteri KUB-AC5 grown under sucrose culture showed to be the best for fast growth and inhibition effects against Salmonella Enteritidis S003 growth. Towards the transcriptome profiling and reporter proteins/metabolites analysis, the results showed that amino acid transport via ABC systems as well as sucrose metabolism and transport are key metabolic responses at Logarithmic (L)-phase of L. reuteri KUB-AC5 growth. Considering the Stationary (S)-phase, we found the potential reporter proteins/metabolites involved in carbohydrate metabolism e.g., levansucrase and levan. Promisingly, levansucrase and levan were revealed to be candidates in relation to inhibition effects of L. reuteri KUB-AC5. Throughout this study, L. reuteri KUB-AC5 had a metabolic control in acclimatization to sucrose and energy pools through transcriptional co-regulation, which supported the cell growth and inhibition potentials. This study offers a perspective in optimizing fermentation condition through either genetic or physiological approaches for enhancing probiotic L. reuteri KUB-AC5 properties.
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Affiliation(s)
- Theeraphol Jatuponwiphat
- Interdisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Thanawat Namrak
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
| | - Sunee Nitisinprasert
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
| | - Massalin Nakphaichit
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
| | - Wanwipa Vongsangnak
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand.,Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand
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42
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Gravina F, Degaut FL, Gerhardt ECM, Pedrosa FO, Souza EM, Antônio de Souza G, Huergo LF. The protein-protein interaction network of the Escherichia coli EIIA Ntr regulatory protein reveals a role in cell motility and metabolic control. Res Microbiol 2021; 172:103882. [PMID: 34563668 DOI: 10.1016/j.resmic.2021.103882] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 01/17/2023]
Abstract
The nitrogen-related PTSNtr system, present in many Proteobacteria including Escherichia coli, acts as a phosphorelay cascade composed of the EINtr, NPr and EIIANtr proteins. Phosphotransfer initiates with phosphoenolpyruvate-dependent EINtr autophosphorylation, the phosphoryl group is then transferred to NPr and finally to a conserved histidine residue on EIIANtr. The reporter metabolites L-glutamine and 2-oxoglutarate reciprocally regulate EINtr autophosphorylation (Lee et al. 2013) and consequently the phosphorylation status of the PTSNtr components is controlled by the availability of nitrogen and carbon. The final phosphate acceptor, EIIANtr, regulates a range of cellular process by acting as the central hub of a complex protein-protein interaction network. Contact between EIIANtr and its target proteins is usually regulated by the EIIANtr phosphorylation status. In this study we performed ligand fishing assays coupled to label-free quantitative proteomics to examine the protein-protein interaction network of E. coli EIIANtr and a phosphomimic variant of the protein. The ligand fishing data, along with phenotypic analysis, indicated that EIIANtr interacts with proteins related to chemotaxis and thereby regulates cell motility. Important metabolic enzymes were also identified as potential EIIANtr binding partners.
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Affiliation(s)
- Fernanda Gravina
- Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Brazil
| | - Flávia L Degaut
- Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Brazil
| | | | - Fabio O Pedrosa
- Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Brazil
| | - Emanuel M Souza
- Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Brazil
| | | | - Luciano F Huergo
- Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Brazil; Setor Litoral, UFPR Matinhos, PR, Brazil.
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43
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Belliveau NM, Chure G, Hueschen CL, Garcia HG, Kondev J, Fisher DS, Theriot JA, Phillips R. Fundamental limits on the rate of bacterial growth and their influence on proteomic composition. Cell Syst 2021; 12:924-944.e2. [PMID: 34214468 PMCID: PMC8460600 DOI: 10.1016/j.cels.2021.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/12/2021] [Accepted: 06/04/2021] [Indexed: 12/11/2022]
Abstract
Despite abundant measurements of bacterial growth rate, cell size, and protein content, we lack a rigorous understanding of what sets the scale of these quantities and when protein abundances should (or should not) depend on growth rate. Here, we estimate the basic requirements and physical constraints on steady-state growth by considering key processes in cellular physiology across a collection of Escherichia coli proteomic data covering ≈4,000 proteins and 36 growth rates. Our analysis suggests that cells are predominantly tuned for the task of cell doubling across a continuum of growth rates; specific processes do not limit growth rate or dictate cell size. We present a model of proteomic regulation as a function of nutrient supply that reconciles observed interdependences between protein synthesis, cell size, and growth rate and propose that a theoretical inability to parallelize ribosomal synthesis places a firm limit on the achievable growth rate. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Nathan M Belliveau
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA
| | - Griffin Chure
- Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christina L Hueschen
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Hernan G Garcia
- Department of Molecular Cell Biology and Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA 02453, USA
| | - Daniel S Fisher
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Julie A Theriot
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA.
| | - Rob Phillips
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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44
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Waite CJ, Lindström Battle A, Bennett MH, Carey MR, Hong CK, Kotta-Loizou I, Buck M, Schumacher J. Resource Allocation During the Transition to Diazotrophy in Klebsiella oxytoca. Front Microbiol 2021; 12:718487. [PMID: 34434180 PMCID: PMC8381380 DOI: 10.3389/fmicb.2021.718487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Free-living nitrogen-fixing bacteria can improve growth yields of some non-leguminous plants and, if enhanced through bioengineering approaches, have the potential to address major nutrient imbalances in global crop production by supplementing inorganic nitrogen fertilisers. However, nitrogen fixation is a highly resource-costly adaptation and is de-repressed only in environments in which sources of reduced nitrogen are scarce. Here we investigate nitrogen fixation (nif) gene expression and nitrogen starvation response signaling in the model diazotroph Klebsiella oxytoca (Ko) M5a1 during ammonium depletion and the transition to growth on atmospheric N2. Exploratory RNA-sequencing revealed that over 50% of genes were differentially expressed under diazotrophic conditions, among which the nif genes are among the most highly expressed and highly upregulated. Isotopically labelled QconCAT standards were designed for multiplexed, absolute quantification of Nif and nitrogen-stress proteins via multiple reaction monitoring mass spectrometry (MRM-MS). Time-resolved Nif protein concentrations were indicative of bifurcation in the accumulation rates of nitrogenase subunits (NifHDK) and accessory proteins. We estimate that the nitrogenase may account for more than 40% of cell protein during diazotrophic growth and occupy approximately half the active ribosome complement. The concentrations of free amino acids in nitrogen-starved cells were insufficient to support the observed rates of Nif protein expression. Total Nif protein accumulation was reduced 10-fold when the NifK protein was truncated and nitrogenase catalysis lost (nifK1–1203), implying that reinvestment of de novo fixed nitrogen is essential for further nif expression and a complete diazotrophy transition. Several amino acids accumulated in non-fixing ΔnifLA and nifK1–1203 mutants, while the rest remained highly stable despite prolonged N starvation. Monitoring post-translational uridylylation of the PII-type signaling proteins GlnB and GlnK revealed distinct nitrogen regulatory roles in Ko M5a1. GlnK uridylylation was persistent throughout the diazotrophy transition while a ΔglnK mutant exhibited significantly reduced Nif expression and nitrogen fixation activity. Altogether, these findings highlight quantitatively the scale of resource allocation required to enable the nitrogen fixation adaptation to take place once underlying signaling processes are fulfilled. Our work also provides an omics-level framework with which to model nitrogen fixation in free-living diazotrophs and inform rational engineering strategies.
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Affiliation(s)
- Christopher J Waite
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Mark H Bennett
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Matthew R Carey
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Chun K Hong
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Martin Buck
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Jörg Schumacher
- Department of Life Sciences, Imperial College London, London, United Kingdom
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45
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Frare R, Stritzler M, Pascuan C, Liebrenz K, Galindo-Sotomonte L, Soto G, Nikel PI, Ayub N. Elimination of GlnKAmtB affects serine biosynthesis and improves growth and stress tolerance of Escherichia coli under nutrient-rich conditions. FEMS Microbiol Lett 2021; 367:6006877. [PMID: 33242092 DOI: 10.1093/femsle/fnaa197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
Nitrogen is a most important nutrient resource for Escherichia coli and other bacteria that harbor the glnKamtB operon, a high-affinity ammonium uptake system highly interconnected with cellular metabolism. Although this system confers an advantage to bacteria when growing under nitrogen-limiting conditions, little is known about the impact of these genes on microbial fitness under nutrient-rich conditions. Here, the genetically tractable E. coli BW25113 strain and its glnKamtB-null mutant (JW0441) were used to analyze the impact of GlnK-AmtB on growth rates and oxidative stress tolerance. Strain JW0441 showed a shorter initial lag phase, higher growth rate, higher citrate synthase activity, higher oxidative stress tolerance and lower expression of serA than strain BW25113 under nutrient-rich conditions, suggesting a fitness cost to increase metabolic plasticity associated with serine metabolism. The overexpression of serA in strain JW0441 resulted in a decreased growth rate and stress tolerance in nutrient-rich conditions similar to that of strain BW25113, suggesting that the negative influence on bacterial fitness imposed by GlnK-AmtB can be traced to the control of serine biosynthesis. Finally, we discuss the potential applications of glnKamtB mutants in bioproduction processes.
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Affiliation(s)
- Romina Frare
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Margarita Stritzler
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Cecilia Pascuan
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Karen Liebrenz
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Luisa Galindo-Sotomonte
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Gabriela Soto
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
| | - Pablo Iván Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Nicolás Ayub
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto de Genética (IGEAF), INTA-CONICET, Buenos Aires, Argentina
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46
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Picchi SC, de Souza E Silva M, Saldanha LL, Ferreira H, Takita MA, Caldana C, de Souza AA. GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri. Sci Rep 2021; 11:15558. [PMID: 34330957 PMCID: PMC8324833 DOI: 10.1038/s41598-021-95113-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022] Open
Abstract
N-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC-MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.
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Affiliation(s)
- Simone Cristina Picchi
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Mariana de Souza E Silva
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Luiz Leonardo Saldanha
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil
| | - Henrique Ferreira
- Departamento de Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, 13506-900, Brazil
| | - Marco Aurélio Takita
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol - Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, 13083-100, Brazil.,Max-Planck-Institut Für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Alessandra Alves de Souza
- Centro de Citricultura "Sylvio Moreira" - Instituto Agronômico de Campinas, Cordeirópolis, São Paulo, 13490-970, Brazil.
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Bueno Batista M, Brett P, Appia-Ayme C, Wang YP, Dixon R. Disrupting hierarchical control of nitrogen fixation enables carbon-dependent regulation of ammonia excretion in soil diazotrophs. PLoS Genet 2021; 17:e1009617. [PMID: 34111137 PMCID: PMC8219145 DOI: 10.1371/journal.pgen.1009617] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/22/2021] [Accepted: 05/23/2021] [Indexed: 12/14/2022] Open
Abstract
The energetic requirements for biological nitrogen fixation necessitate stringent regulation of this process in response to diverse environmental constraints. To ensure that the nitrogen fixation machinery is expressed only under appropriate physiological conditions, the dedicated NifL-NifA regulatory system, prevalent in Proteobacteria, plays a crucial role in integrating signals of the oxygen, carbon and nitrogen status to control transcription of nitrogen fixation (nif) genes. Greater understanding of the intricate molecular mechanisms driving transcriptional control of nif genes may provide a blueprint for engineering diazotrophs that associate with cereals. In this study, we investigated the properties of a single amino acid substitution in NifA, (NifA-E356K) which disrupts the hierarchy of nif regulation in response to carbon and nitrogen status in Azotobacter vinelandii. The NifA-E356K substitution enabled overexpression of nitrogenase in the presence of excess fixed nitrogen and release of ammonia outside the cell. However, both of these properties were conditional upon the nature of the carbon source. Our studies reveal that the uncoupling of nitrogen fixation from its assimilation is likely to result from feedback regulation of glutamine synthetase, allowing surplus fixed nitrogen to be excreted. Reciprocal substitutions in NifA from other Proteobacteria yielded similar properties to the A. vinelandii counterpart, suggesting that this variant protein may facilitate engineering of carbon source-dependent ammonia excretion amongst diverse members of this family.
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Affiliation(s)
| | - Paul Brett
- Department of Metabolic Biology, John Innes Centre, Norwich, United Kingdom
| | - Corinne Appia-Ayme
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, China
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
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Rapid Response of Nitrogen Cycling Gene Transcription to Labile Carbon Amendments in a Soil Microbial Community. mSystems 2021; 6:6/3/e00161-21. [PMID: 33975966 PMCID: PMC8125072 DOI: 10.1128/msystems.00161-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A large portion of activity in soil microbial communities occurs in short time frames in response to an increase in C availability, affecting the biogeochemical cycling of nitrogen. These changes are of particular importance as nitrogen represents both a limiting nutrient for terrestrial plants as well as a potential pollutant. Episodic inputs of labile carbon (C) to soil can rapidly stimulate nitrogen (N) immobilization by soil microorganisms. However, the transcriptional patterns that underlie this process remain unclear. In order to better understand the regulation of N cycling in soil microbial communities, we conducted a 48-h laboratory incubation with agricultural soil where we stimulated the uptake of inorganic N by amending the soil with glucose. We analyzed the metagenome and metatranscriptome of the microbial communities at four time points that corresponded with changes in N availability. The relative abundances of genes remained largely unchanged throughout the incubation. In contrast, glucose addition rapidly increased the transcription of genes encoding ammonium and nitrate transporters, enzymes responsible for N assimilation into biomass, and genes associated with the N regulatory network. This upregulation coincided with an increase in transcripts associated with glucose breakdown and oxoglutarate production, demonstrating a connection between C and N metabolism. When concentrations of ammonium were low, we observed a transient upregulation of genes associated with the nitrogen-fixing enzyme nitrogenase. Transcripts for nitrification and denitrification were downregulated throughout the incubation, suggesting that dissimilatory transformations of N may be suppressed in response to labile C inputs in these soils. These results demonstrate that soil microbial communities can respond rapidly to changes in C availability by drastically altering the transcription of N cycling genes. IMPORTANCE A large portion of activity in soil microbial communities occurs in short time frames in response to an increase in C availability, affecting the biogeochemical cycling of nitrogen. These changes are of particular importance as nitrogen represents both a limiting nutrient for terrestrial plants as well as a potential pollutant. However, we lack a full understanding of the short-term effects of labile carbon inputs on the metabolism of microbes living in soil. Here, we found that soil microbial communities responded to labile carbon addition by rapidly transcribing genes encoding proteins and enzymes responsible for inorganic nitrogen acquisition, including nitrogen fixation. This work demonstrates that soil microbial communities respond within hours to carbon inputs through altered gene expression. These insights are essential for an improved understanding of the microbial processes governing soil organic matter production, decomposition, and nutrient cycling in natural and agricultural ecosystems.
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49
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Prell C, Busche T, Rückert C, Nolte L, Brandenbusch C, Wendisch VF. Adaptive laboratory evolution accelerated glutarate production by Corynebacterium glutamicum. Microb Cell Fact 2021; 20:97. [PMID: 33971881 PMCID: PMC8112011 DOI: 10.1186/s12934-021-01586-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/26/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The demand for biobased polymers is increasing steadily worldwide. Microbial hosts for production of their monomeric precursors such as glutarate are developed. To meet the market demand, production hosts have to be improved constantly with respect to product titers and yields, but also shortening bioprocess duration is important. RESULTS In this study, adaptive laboratory evolution was used to improve a C. glutamicum strain engineered for production of the C5-dicarboxylic acid glutarate by flux enforcement. Deletion of the L-glutamic acid dehydrogenase gene gdh coupled growth to glutarate production since two transaminases in the glutarate pathway are crucial for nitrogen assimilation. The hypothesis that strains selected for faster glutarate-coupled growth by adaptive laboratory evolution show improved glutarate production was tested. A serial dilution growth experiment allowed isolating faster growing mutants with growth rates increasing from 0.10 h-1 by the parental strain to 0.17 h-1 by the fastest mutant. Indeed, the fastest growing mutant produced glutarate with a twofold higher volumetric productivity of 0.18 g L-1 h-1 than the parental strain. Genome sequencing of the evolved strain revealed candidate mutations for improved production. Reverse genetic engineering revealed that an amino acid exchange in the large subunit of L-glutamic acid-2-oxoglutarate aminotransferase was causal for accelerated glutarate production and its beneficial effect was dependent on flux enforcement due to deletion of gdh. Performance of the evolved mutant was stable at the 2 L bioreactor-scale operated in batch and fed-batch mode in a mineral salts medium and reached a titer of 22.7 g L-1, a yield of 0.23 g g-1 and a volumetric productivity of 0.35 g L-1 h-1. Reactive extraction of glutarate directly from the fermentation broth was optimized leading to yields of 58% and 99% in the reactive extraction and reactive re-extraction step, respectively. The fermentation medium was adapted according to the downstream processing results. CONCLUSION Flux enforcement to couple growth to operation of a product biosynthesis pathway provides a basis to select strains growing and producing faster by adaptive laboratory evolution. After identifying candidate mutations by genome sequencing causal mutations can be identified by reverse genetics. As exemplified here for glutarate production by C. glutamicum, this approach allowed deducing rational metabolic engineering strategies.
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Affiliation(s)
- Carina Prell
- Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Tobias Busche
- Technology Platform Genomics, Center for Biotechnology (CeBiTec), Bielefeld University, Sequenz 1, 33615 Bielefeld, Germany
| | - Christian Rückert
- Technology Platform Genomics, Center for Biotechnology (CeBiTec), Bielefeld University, Sequenz 1, 33615 Bielefeld, Germany
| | - Lea Nolte
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Christoph Brandenbusch
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Volker F. Wendisch
- Genetics of Prokaryotes, Faculty of Biology & CeBiTec, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
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50
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Castillo H, Li X, Smith GB. Deinococcus radiodurans UWO298 Dependence on Background Radiation for Optimal Growth. Front Genet 2021; 12:644292. [PMID: 34025716 PMCID: PMC8136434 DOI: 10.3389/fgene.2021.644292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/02/2021] [Indexed: 01/04/2023] Open
Abstract
Ionizing radiation is a major environmental variable for cells on Earth, and so organisms have adapted to either prevent or to repair damages caused by it, primarily from the appearance and accumulation of reactive oxygen species (ROS). In this study, we measured the differential gene expression in Deinococcus radiodurans UWO298 cultures deprived of background ionizing radiation (IR) while growing 605 m underground at the Waste Isolation Pilot Plant (WIPP), reducing the dose rate from 72.1 to 0.9 nGy h–1 from control to treatment, respectively. This reduction in IR dose rate delayed the entry into the exponential phase of the IR-shielded cultures, resulting in a lower biomass accumulation for the duration of the experiment. The RNASeq-based transcriptome analysis showed the differential expression of 0.2 and 2.7% of the D. radiodurans genome after 24 and 34 h of growth in liquid culture, respectively. Gene expression regulation after 34 h was characterized by the downregulation of genes involved in folding newly synthesized and denatured/misfolded proteins, in the assimilation of nitrogen for amino acid synthesis and in the control of copper transport and homeostasis to prevent oxidative stress. We also observed the upregulation of genes coding for proteins with transport and cell wall assembly roles. These results show that D. radiodurans is sensitive to the absence of background levels of ionizing radiation and suggest that its transcriptional response is insufficient to maintain optimal growth.
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Affiliation(s)
- Hugo Castillo
- Human Factors and Behavioral Neurobiology Department, Embry-Riddle Aeronautical University, Daytona Beach, FL, United States
| | - Xiaoping Li
- Virginia Tech Hampton Roads Agriculture Research and Extension Center, Virginia Tech, Blacksburg, VA, United States
| | - Geoffrey B Smith
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
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