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Sun S, Wang Y, He B, Chen J, Leng F, Luo W. Comparative transcriptomics revealed the mechanism of Stenotrophomonas rhizophila JC1 response and biosorption to Pb 2. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2024; 46:231. [PMID: 38849682 DOI: 10.1007/s10653-024-02019-x] [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: 01/15/2024] [Accepted: 04/29/2024] [Indexed: 06/09/2024]
Abstract
Nowadays, there is limited research focusing on the biosorption of Pb2+ through microbial process, particularly at the level of gene expression. To overcome this knowledge gap, we studied the adsorption capacity of Stenotrophomonas rhizophila JC1 to Pb2+, and investigated the physiological mechanism by means of SEM, EDS, FTIR, membrane permeability detection, and investigated the molecular mechanism through comparative transcriptomics. The results showed that after 16 h of cultivation, the biosorption capacity of JC1 for 100 mg/L of Pb2+ reached at 79.8%. The main mechanism of JC1 adsorb Pb2+ is via intracellular accumulation, accounting for more than 90% of the total adsorption. At the physiological level, Pb2+ can precipitate with anion functional groups (e.g., -OH, -NH) on the bacterial cell wall or undergo replacement reaction with cell component elements (e.g., Si, Ca) to adsorb Pb2+ outside of the cell wall, thus accomplishing extracellular adsorption of Pb2+ by strains. Furthermore, the cell membrane acts as a "switch" that inhibits the entry of metal ions into the cell from the plasma membrane. At the molecular level, the gene pbt specificity is responsible for the adsorption of Pb2+ by JC1. In addition, phosphate permease is a major member of the ABC transporter family involved in Pb2+, and czcA/cusA or Co2+/Mg2+ efflux protein plays an important role in the efflux of Pb2+ in JC1. Further, cellular macromolecule biosynthesis, inorganic cation transmembrane transport, citrate cycle (TCA) and carbon metabolism pathways all play crucial roles in the response of strain JC1 to Pb2+ stress.
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Affiliation(s)
- Shangchen Sun
- Yellow River Basin Ecotope Integration of Industry and Education Research Institute, Lanzhou Resources & Environment Voc-Tech University, Lanzhou, 730030, China
| | - Yonggang Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China.
| | - Bihong He
- Yellow River Basin Ecotope Integration of Industry and Education Research Institute, Lanzhou Resources & Environment Voc-Tech University, Lanzhou, 730030, China
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Feifan Leng
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China
| | - Wen Luo
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, Lanzhou, 730050, China
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2
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Wu Y, Zhu M, Ouyang X, Qi X, Guo Z, Yuan Y, Dang Z, Yin H. Integrated transcriptomics and metabolomics analyses reveal the aerobic biodegradation and molecular mechanisms of 2,3',4,4',5-pentachlorodiphenyl (PCB 118) in Methylorubrum sp. ZY-1. CHEMOSPHERE 2024; 356:141921. [PMID: 38588902 DOI: 10.1016/j.chemosphere.2024.141921] [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: 01/26/2024] [Revised: 03/18/2024] [Accepted: 04/04/2024] [Indexed: 04/10/2024]
Abstract
2,3',4,4',5-pentachlorodiphenyl (PCB 118), a highly representative PCB congener, has been frequently detected in various environments, garnering much attention across the scientific community. The degradation of highly chlorinated PCBs by aerobic microorganisms is challenging due to their hydrophobicity and persistence. Herein, the biodegradation and adaptation mechanisms of Methylorubrum sp. ZY-1 to PCB 118 were comprehensively investigated using an integrative approach that combined degradation performance, product identification, metabolomic and transcriptomic analyses. The results indicated that the highest degradation efficiency of 0.5 mg L-1 PCB 118 reached 75.66% after seven days of inoculation when the bacteria dosage was 1.0 g L-1 at pH 7.0. A total of eleven products were identified during the degradation process, including low chlorinated PCBs, hydroxylated PCBs, and ring-opening products, suggesting that strain ZY-1 degraded PCB 118 through dechlorination, hydroxylation, and ring-opening pathways. Metabolomic analysis demonstrated that the energy supply and redox metabolism of strain ZY-1 was disturbed with exposure to PCB 118. To counteract this environmental stress, strain ZY-1 adjusted both the fatty acid synthesis and purine metabolism. The analysis of transcriptomics disclosed that multiple intracellular and extracellular oxidoreductases (e.g., monooxygenase, alpha/beta hydrolase and cytochrome P450) participated in the degradation of PCB 118. Besides, active efflux of PCB 118 and its degradation intermediates mediated by multiple transporters (e.g., MFS transporter and ABC transporter ATP-binding protein) might enhance bacterial resistance against these substances. These discoveries provided the inaugural insights into the biotransformation of strain ZY-1 to PCB 118 stress, illustrating its potential in the remediation of contaminated environments.
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Affiliation(s)
- Yuxuan Wu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Minghan Zhu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Xiaofang Ouyang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Xin Qi
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Zhanyu Guo
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Yibo Yuan
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China; Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, China
| | - Hua Yin
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China; Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, China.
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Ramnarine SDB, Ali O, Jayaraman J, Ramsubhag A. Early transcriptional changes of heavy metal resistance and multiple efflux genes in Xanthomonas campestris pv. campestris under copper and heavy metal ion stress. BMC Microbiol 2024; 24:81. [PMID: 38461228 PMCID: PMC10924375 DOI: 10.1186/s12866-024-03206-7] [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: 01/10/2023] [Accepted: 01/28/2024] [Indexed: 03/11/2024] Open
Abstract
BACKGROUND Copper-induced gene expression in Xanthomonas campestris pv. campestris (Xcc) is typically evaluated using targeted approaches involving qPCR. The global response to copper stress in Xcc and resistance to metal induced damage is not well understood. However, homologs of heavy metal efflux genes from the related Stenotrophomonas genus are found in Xanthomonas which suggests that metal related efflux may also be present. METHODS AND RESULTS Gene expression in Xcc strain BrA1 exposed to 0.8 mM CuSO4.5H2O for 15 minutes was captured using RNA-seq analysis. Changes in expression was noted for genes related to general stress responses and oxidoreductases, biofilm formation, protein folding chaperones, heat-shock proteins, membrane lipid profile, multiple drug and efflux (MDR) transporters, and DNA repair were documented. At this timepoint only the cohL (copper homeostasis/tolerance) gene was upregulated as well as a chromosomal czcCBA efflux operon. An additional screen up to 4 hrs using qPCR was conducted using a wider range of heavy metals. Target genes included a cop-containing heavy metal resistance island and putative metal efflux genes. Several efflux pumps, including a copper resistance associated homolog from S. maltophilia, were upregulated under toxic copper stress. However, these pumps were also upregulated in response to other toxic heavy metals. Additionally, the temporal expression of the coh and cop operons was also observed, demonstrating co-expression of tolerance responses and later activation of part of the cop operon. CONCLUSIONS Overall, initial transcriptional responses focused on combating oxidative stress, mitigating protein damage and potentially increasing resistance to heavy metals and other biocides. A putative copper responsive efflux gene and others which might play a role in broader heavy metal resistance were also identified. Furthermore, the expression patterns of the cop operon in conjunction with other copper responsive genes allowed for a better understanding of the fate of copper ions in Xanthomonas. This work provides useful evidence for further evaluating MDR and other efflux pumps in metal-specific homeostasis and tolerance phenotypes in the Xanthomonas genus. Furthermore, non-canonical copper tolerance and resistance efflux pumps were potentially identified. These findings have implications for interpreting MIC differences among strains with homologous copLAB resistance genes, understanding survival under copper stress, and resistance in disease management.
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Affiliation(s)
- Stephen D B Ramnarine
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Omar Ali
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Jayaraj Jayaraman
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I
| | - Adesh Ramsubhag
- Department of Life Sciences, Faculty of Science and Technology, The University of The West Indies, St. Augustine campus, St. Augustine, Trinidad and Tobago, W. I.
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Chen JS, Hussain B, Tsai HC, Nagarajan V, Koner S, Hsu BM. Analysis and interpretation of hot springs water, biofilms, and sediment bacterial community profiling and their metabolic potential in the area of Taiwan geothermal ecosystem. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159115. [PMID: 36181827 DOI: 10.1016/j.scitotenv.2022.159115] [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: 07/26/2022] [Revised: 09/21/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Microorganisms developed a mechanism that copes with heat, acidity, and high dissolved metal concentrations that likely first evolved. The geothermal fluids emerging in the geothermal springs of Taiwan, located at a subduction zone, are still under signs of progress in the characterization of the various microbial taxonomic changes over time. However, no systematic studies have been performed to compare water, biofilms, and sediment bacterial communities and the primary driving force of dissolved and mineral substrates capable of supporting microbial metabolism. In this study, 16S rRNA gene sequencing was employed for bacterial community exploration, and their potential metabolic pathways involved from water, biofilms, and sediment samples, collected from the geothermal valley (Ti-re-ku). Metagenomic data revealed that the water samples had higher bacterial diversity and richness than biofilms and sediment samples. At the genus level, Alicyclobacillus, Thiomonas, Acidocella, Metallibacterium, Picrophilus, and Legionella were significantly abundant in the water samples. The biofilms were rich in Aciditerrimonas, Bacillus, Acidithiobacillus, and Lysinibacillus, whereas the sediment samples were abundant in Sulfobacillus. The PICRUSt2-predicted functional results revealed that heavy metal-related functions such as heavy-metal exporter system, cobalt‑zinc‑cadmium resistance, arsenical pump, high-affinity nickel-transport, and copper resistance metabolisms were significant in the water samples. Moreover, sulfur-related pathways such as thiosulfate oxidation, dissimilatory sulfate reduction, and assimilatory sulfate reduction were important in water samples, followed by biofilms and sediment. Therefore, our findings highlighted the comparative taxonomic diversity and functional composition contributions to geothermal fluid, with implications for understanding the evolution and ecological niche dimension of microbes which are the key to geothermal ecosystem function.
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Affiliation(s)
- Jung-Sheng Chen
- Department of Medical Research, E-Da Hospital, Kaohsiung City 824, Taiwan
| | - Bashir Hussain
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi County 621, Taiwan; Department of Biomedical Sciences, National Chung Cheng University, Chiayi County 621, Taiwan
| | - Hsin-Chi Tsai
- Department of Psychiatry, School of Medicine, Tzu Chi University, Hualien 970, Taiwan; Department of Psychiatry, Tzu-Chi General Hospital, Hualien 970, Taiwan
| | - Viji Nagarajan
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi County 621, Taiwan
| | - Suprokash Koner
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi County 621, Taiwan; Department of Biomedical Sciences, National Chung Cheng University, Chiayi County 621, Taiwan
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi County 621, Taiwan; Center for Innovative Research on Aging Society (CIRAS), National Chung Cheng University, Chiayi County 621, Taiwan.
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5
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HongE Y, Wan Z, Kim Y, Yu J. Submerged zone and vegetation drive distribution of heavy metal fractions and microbial community structure: Insights into stormwater biofiltration system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158367. [PMID: 36049683 DOI: 10.1016/j.scitotenv.2022.158367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 05/27/2023]
Abstract
Biofiltration system is a widely used stormwater treatment option that is effective in removing heavy metals. The concentration and distribution of heavy metal fractions in biofiltration filter media, as well as the microbiota composition affected by the design parameters, are relatively novel concepts that require further research. A laboratory-scale column study was conducted to investigate the microbial community and the fractionation of heavy metals (Pb, Cu, Cr, and Cd) extracted from filter media samples, subjected to the presence of vegetation, submerged zone (SZ), and major environmental parameters (pH, water content). Sequential extractions revealed that, compared to the three other fractions (exchangeable fraction, reducible fraction, and oxidizable fraction), the residual fraction was the most represented for each metal (41 - 82 %). As a result, vegetation was found to reduce pH value, and significantly decrease the concentration of the exchangeable fraction of Pb in the middle layer, and the oxidizable fraction of Pb, Cu, Cd, and Cr in the middle and bottom layers (p < 0.05). The formation of an anoxic environment by submerged zone settlements resulted in a significant decrease in the concentration of reducible fractions and a significant increase in the concentration of oxidizable fractions for four heavy metals (p < 0.05). In addition, the analysis of the microbiota showed that the diversity and richness of microorganisms increased in the presence of SZ and plants. The dominant phylum in biofiltration was Proteobacteria, followed by Firmicutes, Bacteroidetes, Acidobacteria, and Actinobacteria as major phyla. Heavy metal fractions could regulate the structure of microbial communities in biofiltration. The findings of this study would enrich our understanding of the improvement of multi-metal-contaminated runoff treatment and highlight the impact of design parameters and heavy metal fractionation on microbial community structure in the biofiltration system.
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Affiliation(s)
- Yusheng HongE
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Zeyi Wan
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Youngchul Kim
- Department of Environmental Engineering, Hanseo University, Seosan City 356-706, Republic of Korea.
| | - Jianghua Yu
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China.
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6
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Wand ME, Sutton JM. Efflux-mediated tolerance to cationic biocides, a cause for concern? MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748532 DOI: 10.1099/mic.0.001263] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
AbstractWith an increase in the number of isolates resistant to multiple antibiotics, infection control has become increasingly important to help combat the spread of multi-drug-resistant pathogens. An important component of this is through the use of disinfectants and antiseptics (biocides). Antibiotic resistance has been well studied in bacteria, but little is known about potential biocide resistance genes and there have been few reported outbreaks in hospitals resulting from a breakdown in biocide effectiveness. Development of increased tolerance to biocides has been thought to be more difficult due to the mode of action of biocides which affect multiple cellular targets compared with antibiotics. Very few genes which contribute towards increased biocide tolerance have been identified. However, the majority of those that have are components or regulators of different efflux pumps or genes which modulate membrane function/modification. This review will examine the role of efflux in increased tolerance towards biocides, focusing on cationic biocides and heavy metals against Gram-negative bacteria. As many efflux pumps which are upregulated by biocide presence also contribute towards an antimicrobial resistance phenotype, the role of these efflux pumps in cross-resistance to both other biocides and antibiotics will be explored.
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Affiliation(s)
- Matthew E Wand
- Technology Development Group, UK Health Security Agency, Research and Evaluation, Porton Down, Salisbury, Wiltshire, SP4 0JG, UK
| | - J Mark Sutton
- Technology Development Group, UK Health Security Agency, Research and Evaluation, Porton Down, Salisbury, Wiltshire, SP4 0JG, UK
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Sun S, Zhang K, Wu Y, Zhu N, Wang Y, Chen J, Leng F. Transporter drives the biosorption of heavy metals by Stenotrophomonas rhizophila JC1. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:45380-45395. [PMID: 35143001 DOI: 10.1007/s11356-022-18900-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
To better understand the function of transporter in heavy metal detoxification of bacteria, the transporters associated with heavy metal detoxification in S. rhizophila JC1 were analyzed, among which four members were verified by RT-qPCR. In addition, the removal rates of four single metal ions (Cr6+, Cu2+, Zn2+, Pb2+) and polymetallic ions by strain JC1 were studied, respectively. We also researched the physiological response of strain JC1 to different metal stress via morphological observation, elemental composition, functional group and membrane permeability analysis. The results showed that in the single metal ion solution, removal capacities of Cu2+ (120 mg/L) and Cr6+ (80 mg/L) of S. rhizophila JC1 reached to 79.9% and 89.3%, respectively, while in polymetallic ions solution, the removal capacity of each metal ion all decreased, and in detail, the adsorption capacity was determined Cr6+>Cu2+>Zn2+>Pb2+ under the same condition. The physiological response analyses results showed that extracellular adsorption phenomena occurred, and the change of membrane permeability hindered the uptake of metal ions by bacteria. The analysis of transporters in strain JC1 genome illustrated that a total of 323 transporters were predicted. Among them, two, six and five proteins of the cation diffusion facilitator, resistance-nodulation-division efflux and P-type ATPase families were, respectively, predicted. The expression of corresponding genes showed that the synergistic action of correlative transporters played important roles in the process of adsorption. The comparative genomics analysis revealed that S. rhizophila JC1 has long-distance evolutionary relationships with other strains, but the efflux system of S. rhizophila JC1 contained the same types of metal transporters as other metal-resistant bacteria.
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Affiliation(s)
- Shangchen Sun
- School of Petrochemical Engineering, Lanzhou University of Technology, 730050, Lanzhou, China
| | - Kexin Zhang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Yamiao Wu
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Ning Zhu
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
| | - Yonggang Wang
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China.
| | - Jixiang Chen
- School of Petrochemical Engineering, Lanzhou University of Technology, 730050, Lanzhou, China
| | - Feifan Leng
- School of Life Science and Engineering, Lanzhou University of Technology, Langongping Road 287, Qilihe District, 730050, Lanzhou, China
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Hussain S, Khan M, Sheikh TMM, Mumtaz MZ, Chohan TA, Shamim S, Liu Y. Zinc Essentiality, Toxicity, and Its Bacterial Bioremediation: A Comprehensive Insight. Front Microbiol 2022; 13:900740. [PMID: 35711754 PMCID: PMC9197589 DOI: 10.3389/fmicb.2022.900740] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/09/2022] [Indexed: 02/04/2023] Open
Abstract
Zinc (Zn) is one of the most abundantly found heavy metals in the Earth's crust and is reported to be an essential trace metal required for the growth of living beings, with it being a cofactor of major proteins, and mediating the regulation of several immunomodulatory functions. However, its essentiality also runs parallel to its toxicity, which is induced through various anthropogenic sources, constant exposure to polluted sites, and other natural phenomena. The bioavailability of Zn is attributable to various vegetables, beef, and dairy products, which are a good source of Zn for safe consumption by humans. However, conditions of Zn toxicity can also occur through the overdosage of Zn supplements, which is increasing at an alarming rate attributing to lack of awareness. Though Zn toxicity in humans is a treatable and non-life-threatening condition, several symptoms cause distress to human activities and lifestyle, including fever, breathing difficulty, nausea, chest pain, and cough. In the environment, Zn is generally found in soil and water bodies, where it is introduced through the action of weathering, and release of industrial effluents, respectively. Excessive levels of Zn in these sources can alter soil and aquatic microbial diversity, and can thus affect the bioavailability and absorption of other metals as well. Several Gram-positive and -negative species, such as Bacillus sp., Staphylococcus sp., Streptococcus sp., and Escherichia coli, Pseudomonas sp., Klebsiella sp., and Enterobacter sp., respectively, have been reported to be promising agents of Zn bioremediation. This review intends to present an overview of Zn and its properties, uses, bioavailability, toxicity, as well as the major mechanisms involved in its bioremediation from polluted soil and wastewaters.
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Affiliation(s)
- Sarfraz Hussain
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, China
| | - Maryam Khan
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Taha Majid Mahmood Sheikh
- Institute of Plant Protection, Jiangsu Academy of Agriculture Sciences, Nanjing, China,*Correspondence: Taha Majid Mahmood Sheikh,
| | - Muhammad Zahid Mumtaz
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Talha Ali Chohan
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Saba Shamim
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan,Saba Shamim,
| | - Yuhong Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, China,Yuhong Liu,
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Nagarajan V, Tsai HC, Chen JS, Hussain B, Fan CW, Asif A, Hsu BM. The Evaluation of Bacterial Abundance and Functional Potentials in the Three Major Watersheds, Located in the Hot Spring Zone of the Tatun Volcano Group Basin, Taiwan. Microorganisms 2022; 10:microorganisms10030500. [PMID: 35336075 PMCID: PMC8949176 DOI: 10.3390/microorganisms10030500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 12/10/2022] Open
Abstract
The Tatun Volcanic Group (TVG), located in northern Taiwan, is characterized by acidic hot springs where the outflow of the hot springs may affect the properties of the associated lotic water bodies. We investigated the bacterial diversity and functional profiles of the Peihuang (PHC), HuangGang (HGC), and Nanhuang Creeks (NHC) located in the TVG basin using 16S rRNA gene sequencing coupled with statistical analyses. Water samples were collected from various streams of the creeks for two months of the year. The NHC showed the highest diversity, richness, and a unique number of phyla, which was followed by the HGC. A reduced number of phyla and a lower diversity was noticed in the PHC. The NHC was found to be abundant in the genera Armatimonas, Prosthecobacter, Pirellula, and Bdellovibrio, whereas the HGC was rich in Thiomonas, Acidiphilium, Prevotella, Acidocella, Acidithiobacillus, and Metallibacterium. The PHC was abundant in Thiomonsa, Legionella, Acidocella, and Sulfuriferula. The samples did not show any strong seasonal variations with the bacterial diversity and abundance; however, the relative abundance of each sampling site varied within the sampling months. The iron transport protein- and the sulfur metabolism-related pathways were predicted to be the key functions in all the creeks, whereas the heavy metal-related functions, such as the cobalt/nickel transport protein and the cobalt–zinc–cadmium efflux system were found to be abundant in the HGC and PHC, respectively. The abundance of Bdellovibrio in the NHC, Diplorickettsia in the HGC, and Legionella in the PHC samples indicated a higher anthropogenic impact over the creek water quality. This study provides the data to understand the distinct bacterial community structure, as well as the functional potentials of the three major watersheds, and helps the knowledge of the impact of the physicochemical properties of the TVG hot springs upon the watersheds.
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Affiliation(s)
- Viji Nagarajan
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan; (V.N.); (B.H.); (C.-W.F.); (A.A.)
| | - Hsin-Chi Tsai
- Department of Psychiatry, School of Medicine, Tzu Chi University, Hualien 970, Taiwan;
- Department of Psychiatry, Tzu-Chi General Hospital, Hualien 970, Taiwan
| | - Jung-Sheng Chen
- Department of Medical Research, E-Da Hospital, Kaohsiung 824, Taiwan;
| | - Bashir Hussain
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan; (V.N.); (B.H.); (C.-W.F.); (A.A.)
- Department of Biomedical Sciences, National Chung Cheng University, Chiayi 621, Taiwan
| | - Cheng-Wei Fan
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan; (V.N.); (B.H.); (C.-W.F.); (A.A.)
| | - Aslia Asif
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan; (V.N.); (B.H.); (C.-W.F.); (A.A.)
- Doctoral Program in Science, Technology, Environment and Mathematics (STEM), National Chung Cheng University, Chiayi 621, Taiwan
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan; (V.N.); (B.H.); (C.-W.F.); (A.A.)
- Correspondence: ; Tel.: +886-52-720-411 (ext. 66218)
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Tripathi AK, Saxena P, Thakur P, Rauniyar S, Samanta D, Gopalakrishnan V, Singh RN, Sani RK. Transcriptomics and Functional Analysis of Copper Stress Response in the Sulfate-Reducing Bacterium Desulfovibrio alaskensis G20. Int J Mol Sci 2022; 23:ijms23031396. [PMID: 35163324 PMCID: PMC8836040 DOI: 10.3390/ijms23031396] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 01/27/2023] Open
Abstract
Copper (Cu) is an essential micronutrient required as a co-factor in the catalytic center of many enzymes. However, excess Cu can generate pleiotropic effects in the microbial cell. In addition, leaching of Cu from pipelines results in elevated Cu concentration in the environment, which is of public health concern. Sulfate-reducing bacteria (SRB) have been demonstrated to grow in toxic levels of Cu. However, reports on Cu toxicity towards SRB have primarily focused on the degree of toxicity and subsequent elimination. Here, Cu(II) stress-related effects on a model SRB, Desulfovibrio alaskensis G20, is reported. Cu(II) stress effects were assessed as alterations in the transcriptome through RNA-Seq at varying Cu(II) concentrations (5 µM and 15 µM). In the pairwise comparison of control vs. 5 µM Cu(II), 61.43% of genes were downregulated, and 38.57% were upregulated. In control vs. 15 µM Cu(II), 49.51% of genes were downregulated, and 50.5% were upregulated. The results indicated that the expression of inorganic ion transporters and translation machinery was massively modulated. Moreover, changes in the expression of critical biological processes such as DNA transcription and signal transduction were observed at high Cu(II) concentrations. These results will help us better understand the Cu(II) stress-response mechanism and provide avenues for future research.
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Affiliation(s)
- Abhilash Kumar Tripathi
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Priya Saxena
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Payal Thakur
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Shailabh Rauniyar
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Dipayan Samanta
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Vinoj Gopalakrishnan
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Ram Nageena Singh
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Rajesh Kumar Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (A.K.T.); (P.S.); (P.T.); (S.R.); (D.S.); (V.G.); (R.N.S.)
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
- Composite and Nanocomposite Advanced Manufacturing Centre—Biomaterials, Rapid City, SD 57701, USA
- Correspondence:
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Mathivanan K, Chandirika JU, Vinothkanna A, Yin H, Liu X, Meng D. Bacterial adaptive strategies to cope with metal toxicity in the contaminated environment - A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 226:112863. [PMID: 34619478 DOI: 10.1016/j.ecoenv.2021.112863] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Heavy metal contamination poses a serious environmental hazard, globally necessitating intricate attention. Heavy metals can cause deleterious health hazards to humans and other living organisms even at low concentrations. Environmental biotechnologists and eco-toxicologists have rigorously assessed a plethora of bioremediation mechanisms that can hamper the toxic outcomes and the molecular basis for rejuvenating the hazardous impacts, optimistically. Environmental impact assessment and restoration of native and positive scenario has compelled biological management in ensuring safety replenishment in polluted realms often hindered by heavy metal toxicity. Copious treatment modalities have been corroborated to mitigate the detrimental effects to remove heavy metals from polluted sites. In particular, Biological-based treatment methods are of great attention in the metal removal sector due to their high efficiency at low metal concentrations, ecofriendly nature, and cost-effectiveness. Due to rapid multiplication and growth rates, bacteria having metal resistance are advocated for metal removal applications. Evolutionary implications of coping with heavy metals toxicity have redressed bacterial adaptive/resistance strategies related to physiological and cross-protective mechanisms. Ample reviews have been reported for the bacterial adaptive strategies to cope with heavy metal toxicity. Nevertheless, a holistic review summarizing the redox reactions that address the cross-reactivity mechanisms between metallothionein synthesis, extracellular polysaccharides production, siderophore production, and efflux systems of metal resistant bacteria are scarce. Molecular dissection of how bacteria adapt themselves to metal toxicity can augment novel and innovative technologies for efficient detoxification, removal, and combat the restorative difficulties for stress alleviations. The present comprehensive compilation addresses the identification of newer methodologies, summarizing the prevailing strategies of adaptive/resistance mechanisms in bacterial bioremediation. Further pitfalls and respective future directions are enumerated in invigorating effective bioremediation technologies including overexpression studies and delivery systems. The analysis will aid in abridging the gap for limitations in heavy metal removal strategies and necessary cross-talk in elucidating the complex cascade of events in better bioremediation protocols.
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Affiliation(s)
- Krishnamurthy Mathivanan
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR China; Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, PR China
| | - Jayaraman Uthaya Chandirika
- Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu 627412, India
| | - Annadurai Vinothkanna
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, PR China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR China; Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, PR China; The Hunan International Scientific and Technological Cooperation Base of Environmental Microbiome and Application, Central South University, Changsha 410083, PR China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR China; Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, PR China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, PR China; Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, PR China; The Hunan International Scientific and Technological Cooperation Base of Environmental Microbiome and Application, Central South University, Changsha 410083, PR China.
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de Araújo HL, Martins BP, Vicente AM, Lorenzetti APR, Koide T, Marques MV. Cold Regulation of Genes Encoding Ion Transport Systems in the Oligotrophic Bacterium Caulobacter crescentus. Microbiol Spectr 2021; 9:e0071021. [PMID: 34479415 PMCID: PMC8552747 DOI: 10.1128/spectrum.00710-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022] Open
Abstract
In this study, we characterize the response of the free-living oligotrophic alphaproteobacterium Caulobacter crescentus to low temperatures by global transcriptomic analysis. Our results showed that 656 genes were upregulated and 619 were downregulated at least 2-fold after a temperature downshift. The identified differentially expressed genes (DEG) belong to several functional categories, notably inorganic ion transport and metabolism, and a subset of these genes had their expression confirmed by reverse transcription quantitative real-time PCR (RT-qPCR). Several genes belonging to the ferric uptake regulator (Fur) regulon were downregulated, indicating that iron homeostasis is relevant for adaptation to cold. Several upregulated genes encode proteins that interact with nucleic acids, particularly RNA: cspA, cspB, and the DEAD box RNA helicases rhlE, dbpA, and rhlB. Moreover, 31 small regulatory RNAs (sRNAs), including the cell cycle-regulated noncoding RNA (ncRNA) CcnA, were upregulated, indicating that posttranscriptional regulation is important for the cold stress response. Interestingly, several genes related to transport were upregulated under cold stress, including three AcrB-like cation/multidrug efflux pumps, the nitrate/nitrite transport system, and the potassium transport genes kdpFABC. Further characterization showed that kdpA is upregulated in a potassium-limited medium and at a low temperature in a SigT-independent way. kdpA mRNA is less stable in rho and rhlE mutant strains, but while the expression is positively regulated by RhlE, it is negatively regulated by Rho. A kdpA-deleted strain was generated, and its viability in response to osmotic, acidic, or cold stresses was determined. The implications of such variation in the gene expression for cold adaptation are discussed. IMPORTANCE Low-temperature stress is an important factor for nucleic acid stability and must be circumvented in order to maintain the basic cell processes, such as transcription and translation. The oligotrophic lifestyle presents further challenges to ensure the proper nutrient uptake and osmotic balance in an environment of slow nutrient flow. Here, we show that in Caulobacter crescentus, the expression of the genes involved in cation transport and homeostasis is altered in response to cold, which could lead to a decrease in iron uptake and an increase in nitrogen and high-affinity potassium transport by the Kdp system. This previously uncharacterized regulation of the Kdp transporter has revealed a new mechanism for adaptation to low temperatures that may be relevant for oligotrophic bacteria.
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Affiliation(s)
- Hugo L. de Araújo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Bianca P. Martins
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Alexandre M. Vicente
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Alan P. R. Lorenzetti
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Tie Koide
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marilis V. Marques
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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Maertens L, Cherry P, Tilquin F, Van Houdt R, Matroule JY. Environmental Conditions Modulate the Transcriptomic Response of Both Caulobacter crescentus Morphotypes to Cu Stress. Microorganisms 2021; 9:1116. [PMID: 34064119 PMCID: PMC8224329 DOI: 10.3390/microorganisms9061116] [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: 04/26/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria encounter elevated copper (Cu) concentrations in multiple environments, varying from mining wastes to antimicrobial applications of copper. As the role of the environment in the bacterial response to Cu ion exposure remains elusive, we used a tagRNA-seq approach to elucidate the disparate responses of two morphotypes of Caulobacter crescentus NA1000 to moderate Cu stress in a complex rich (PYE) medium and a defined poor (M2G) medium. The transcriptome was more responsive in M2G, where we observed an extensive oxidative stress response and reconfiguration of the proteome, as well as the induction of metal resistance clusters. In PYE, little evidence was found for an oxidative stress response, but several transport systems were differentially expressed, and an increased need for histidine was apparent. These results show that the Cu stress response is strongly dependent on the cellular environment. In addition, induction of the extracytoplasmic function sigma factor SigF and its regulon was shared by the Cu stress responses in both media, and its central role was confirmed by the phenotypic screening of a sigF::Tn5 mutant. In both media, stalked cells were more responsive to Cu stress than swarmer cells, and a stronger basal expression of several cell protection systems was noted, indicating that the swarmer cell is inherently more Cu resistant. Our approach also allowed for detecting several new transcription start sites, putatively indicating small regulatory RNAs, and additional levels of Cu-responsive regulation.
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Affiliation(s)
- Laurens Maertens
- Microbiology Unit, Interdisciplinary Biosciences, Belgian Nuclear Research Centre (SCK CEN), 2400 Mol, Belgium; (L.M.); (R.V.H.)
- Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, 5000 Namur, Belgium; (P.C.); (F.T.)
| | - Pauline Cherry
- Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, 5000 Namur, Belgium; (P.C.); (F.T.)
| | - Françoise Tilquin
- Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, 5000 Namur, Belgium; (P.C.); (F.T.)
| | - Rob Van Houdt
- Microbiology Unit, Interdisciplinary Biosciences, Belgian Nuclear Research Centre (SCK CEN), 2400 Mol, Belgium; (L.M.); (R.V.H.)
| | - Jean-Yves Matroule
- Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, 5000 Namur, Belgium; (P.C.); (F.T.)
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14
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Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
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Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
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15
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Gallardo-Benavente C, Campo-Giraldo JL, Castro-Severyn J, Quiroz A, Pérez-Donoso JM. Genomics Insights into Pseudomonas sp. CG01: An Antarctic Cadmium-Resistant Strain Capable of Biosynthesizing CdS Nanoparticles Using Methionine as S-Source. Genes (Basel) 2021; 12:genes12020187. [PMID: 33514061 PMCID: PMC7912247 DOI: 10.3390/genes12020187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 12/23/2022] Open
Abstract
Here, we present the draft genome sequence of Pseudomonas sp. GC01, a cadmium-resistant Antarctic bacterium capable of biosynthesizing CdS fluorescent nanoparticles (quantum dots, QDs) employing a unique mechanism involving the production of methanethiol (MeSH) from methionine (Met). To explore the molecular/metabolic components involved in QDs biosynthesis, we conducted a comparative genomic analysis, searching for the genes related to cadmium resistance and sulfur metabolic pathways. The genome of Pseudomonas sp. GC01 has a 4,706,645 bp size with a 58.61% G+C content. Pseudomonas sp. GC01 possesses five genes related to cadmium transport/resistance, with three P-type ATPases (cadA, zntA, and pbrA) involved in Cd-secretion that could contribute to the extracellular biosynthesis of CdS QDs. Furthermore, it exhibits genes involved in sulfate assimilation, cysteine/methionine synthesis, and volatile sulfur compounds catabolic pathways. Regarding MeSH production from Met, Pseudomonas sp. GC01 lacks the genes E4.4.1.11 and megL for MeSH generation. Interestingly, despite the absence of these genes, Pseudomonas sp. GC01 produces high levels of MeSH. This is probably associated with the metC gene that also produces MeSH from Met in bacteria. This work is the first report of the potential genes involved in Cd resistance, sulfur metabolism, and the process of MeSH-dependent CdS QDs bioproduction in Pseudomonas spp. strains.
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Affiliation(s)
- Carla Gallardo-Benavente
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, 4780000 Temuco, Chile;
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
| | - Jessica L. Campo-Giraldo
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
| | - Juan Castro-Severyn
- Laboratorio de Microbiología Aplicada y Extremófilos, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte, 1240000 Antofagasta, Chile;
| | - Andrés Quiroz
- Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente (CIBAMA), Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
- Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, 4780000 Temuco, Chile
- Correspondence: (A.Q.); (J.M.P.-D.)
| | - José M. Pérez-Donoso
- BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, 8320000 Santiago, Chile;
- Correspondence: (A.Q.); (J.M.P.-D.)
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An X, Tian C, Xu J, Dong F, Liu X, Wu X, Zheng Y. Characterization of hexaconazole-degrading strain Sphingobacterium multivorum and analysis of transcriptome for biodegradation mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 722:137171. [PMID: 32213434 DOI: 10.1016/j.scitotenv.2020.137171] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/02/2020] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
Hexaconazole is a triazole fungicide, which is stable and difficult to degrade in the environment. The existence of hexaconazole could pose a certain risk to the environment and the health of living organisms. In this study, an efficient degradation strain B-3 (Sphingobacterium multivorum) of hexaconazole was isolated from sewage, activated sludge, and soil. The degradation efficiency of hexaconazole can reach 85.6% in 6 days at a temperature of 32.5 °C, pH of 6.31, initial inoculum of 0.4 g L-1 and initial concentration of hexaconazole of 50 mg L-1. During degradation, three metabolites (M1: 2-(2, 4-dichlorophenyl)-1-(1H-1, 2, 4-triazol-1-yl) hexane-2, 5-diol; M2: 2-(2, 4-dichlorophenyl) hexane-1, 2-diol; M3: 1H-1, 2, 4-triazole) were identified. Moreover, 45.6% hexaconazole can be degraded in 60 days in natural soil containing B-3. The results of the transcriptome sequencing indicated the presence of 864 differential genes, in which aldehyde dehydrogenase, monooxygenase, RND transporters, and ABC transporters were up-regulated. The generation of 2-(2, 4-dichlorophenyl)-1-(1H-1, 2, 4-triazol-1-yl) hexane-2, 5-diol may be due to the participation of monooxygenase.
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Affiliation(s)
- Xiaokang An
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunyan Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jun Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Fengshou Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xingang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaohu Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongquan Zheng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Effects of cadmium perturbation on the microbial community structure and heavy metal resistome of a tropical agricultural soil. BIORESOUR BIOPROCESS 2020. [DOI: 10.1186/s40643-020-00314-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractThe effects of cadmium (Cd) contamination on the microbial community structure, soil physicochemistry and heavy metal resistome of a tropical agricultural soil were evaluated in field-moist soil microcosms. A Cd-contaminated agricultural soil (SL5) and an untreated control (SL4) were compared over a period of 5 weeks. Analysis of the physicochemical properties and heavy metals content of the two microcosms revealed a statistically significant decrease in value of the soil physicochemical parameters (P < 0.05) and concentration of heavy metals (Cd, Pb, Cr, Zn, Fe, Cu, Se) content of the agricultural soil in SL5 microcosm. Illumina shotgun sequencing of the DNA extracted from the two microcosms showed the predominance of the phyla, classes, genera and species of Proteobacteria (37.38%), Actinobacteria (35.02%), Prevotella (6.93%), and Conexibacter woesei (8.93%) in SL4, and Proteobacteria (50.50%), Alphaproteobacteria (22.28%), Methylobacterium (9.14%), and Methylobacterium radiotolerans (12,80%) in SL5, respectively. Statistically significant (P < 0.05) difference between the metagenomes was observed at genus and species delineations. Functional annotation of the two metagenomes revealed diverse heavy metal resistome for the uptake, transport, efflux and detoxification of various heavy metals. It also revealed the exclusive detection in SL5 metagenome of members of RND (resistance nodulation division) protein czcCBA efflux system (czcA, czrA, czrB), CDF (cation diffusion facilitator) transporters (czcD), and genes for enzymes that protect the microbial cells against cadmium stress (sodA, sodB, ahpC). The results obtained in this study showed that Cd contamination significantly affects the soil microbial community structure and function, modifies the heavy metal resistome, alters the soil physicochemistry and results in massive loss of some autochthonous members of the community not adapted to the Cd stress.
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Recent Progress in Metal-Microbe Interactions: Prospects in Bioremediation. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2019. [DOI: 10.22207/jpam.13.1.02] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Xu C, Sun T, Li S, Chen L, Zhang W. Adaptive laboratory evolution of cadmium tolerance in Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:205. [PMID: 30061927 PMCID: PMC6058365 DOI: 10.1186/s13068-018-1205-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/16/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND Cadmium has been a significant threat to environment and human health due to its high toxicity and wide application in fossil-fuel burning and battery industry. Cyanobacteria are one of the most dominant prokaryotes, and the previous studies suggested that they could be valuable in removing Cd2+ from waste water. However, currently, the tolerance to cadmium is very low in cyanobacteria. To further engineer cyanobacteria for the environmental application, it is thus necessary to determine the mechanism that they respond to high concentration of cadmium. RESULTS In this study, a robust strain of Synechocystis PCC 6803 (named ALE-9.0) tolerant to CdSO4 with a concentration up to 9.0 µM was successfully isolated via adaptive laboratory evolution over 802-day continuous passages under cadmium stress. Whole-genome re-sequencing was then performed and nine mutations were identified for the evolved strain compared to the wild-type strain. Among these mutations, a large fragment deletion in slr0454 encoding a cation or drug efflux system protein was found to contribute directly to the resistance to Cd2+ stress. In addition, five other mutations were also demonstrated related to the improved Cd2+ tolerance in ALE-9.0. Moreover, the evolved ALE-9.0 strain was found to obtain cross tolerance to some other heavy metals like zinc and cobalt as well as higher resistance to high light. CONCLUSIONS The work here identified six genes and their mutations related to Cd2+ tolerance in Synechocystis PCC 6803, and demonstrated the feasibility of adaptive laboratory evolution in tolerance modifications. This work also provided valuable information regarding the cadmium tolerance mechanism in Synechocystis PCC 6803, and useful insights for cyanobacterial robustness and tolerance engineering.
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Affiliation(s)
- Chunxiao Xu
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072 People’s Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, People’s Republic of China
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072 People’s Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, People’s Republic of China
| | - Shubin Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072 People’s Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, People’s Republic of China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072 People’s Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, People’s Republic of China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072 People’s Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, People’s Republic of China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, People’s Republic of China
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20
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Park DM, Overton KW, Liou MJ, Jiao Y. Identification of a U/Zn/Cu responsive global regulatory two-component system in Caulobacter crescentus. Mol Microbiol 2017; 104:46-64. [PMID: 28035693 DOI: 10.1111/mmi.13615] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2016] [Indexed: 01/18/2023]
Abstract
Despite the well-known toxicity of uranium (U) to bacteria, little is known about how cells sense and respond to U. The recent finding of a U-specific stress response in Caulobacter crescentus has provided a foundation for studying the mechanisms of U- perception in bacteria. To gain insight into this process, we used a forward genetic screen to identify the regulatory components governing expression of the urcA promoter (PurcA ) that is strongly induced by U. This approach unearthed a previously uncharacterized two-component system, named UzcRS, which is responsible for U-dependent activation of PurcA . UzcRS is also highly responsive to zinc and copper, revealing a broader specificity than previously thought. Using ChIP-seq, we found that UzcR binds extensively throughout the genome in a metal-dependent manner and recognizes a noncanonical DNA-binding site. Coupling the genome-wide occupancy data with RNA-seq analysis revealed that UzcR is a global regulator of transcription, predominately activating genes encoding proteins that are localized to the cell envelope; these include metallopeptidases, multidrug-resistant efflux (MDR) pumps, TonB-dependent receptors and many proteins of unknown function. Collectively, our data suggest that UzcRS couples the perception of U, Zn and Cu with a novel extracytoplasmic stress response.
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Affiliation(s)
- Dan M Park
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - K Wesley Overton
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Megan J Liou
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Yongqin Jiao
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
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21
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Qian C, Johs A, Chen H, Mann BF, Lu X, Abraham PE, Hettich RL, Gu B. Global Proteome Response to Deletion of Genes Related to Mercury Methylation and Dissimilatory Metal Reduction Reveals Changes in Respiratory Metabolism in Geobacter sulfurreducens PCA. J Proteome Res 2016; 15:3540-3549. [PMID: 27463218 DOI: 10.1021/acs.jproteome.6b00263] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Geobacter sulfurreducens PCA can reduce, sorb, and methylate mercury (Hg); however, the underlying biochemical mechanisms of these processes and interdependent metabolic pathways remain unknown. In this study, shotgun proteomics was used to compare global proteome profiles between wild-type G. sulfurreducens PCA and two mutant strains: a ΔhgcAB mutant, which is deficient in two genes known to be essential for Hg methylation and a ΔomcBESTZ mutant, which is deficient in five outer membrane c-type cytochromes and thus impaired in its ability for dissimilatory metal ion reduction. We were able to delineate the global response of G. sulfurreducens PCA in both mutants and identify cellular networks and metabolic pathways that were affected by the loss of these genes. Deletion of hgcAB increased the relative abundances of proteins implicated in extracellular electron transfer, including most of the c-type cytochromes, PilA-C, and OmpB, and is consistent with a previously observed increase in Hg reduction in the ΔhgcAB mutant. Deletion of omcBESTZ was found to significantly increase relative abundances of various methyltransferases, suggesting that a loss of dissimilatory reduction capacity results in elevated activity among one-carbon (C1) metabolic pathways and thus increased methylation. We show that G. sulfurreducens PCA encodes only the folate branch of the acetyl-CoA pathway, and proteins associated with the folate branch were found at lower abundance in the ΔhgcAB mutant strain than the wild type. This observation supports the hypothesis that the function of HgcA and HgcB is linked to C1 metabolism through the folate branch of the acetyl-CoA pathway by providing methyl groups required for Hg methylation.
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Affiliation(s)
- Chen Qian
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.,Graduate School of Genome Science and Technology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Alexander Johs
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Hongmei Chen
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Benjamin F Mann
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Xia Lu
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Paul E Abraham
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Robert L Hettich
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.,Graduate School of Genome Science and Technology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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22
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Transposon Mutagenesis Paired with Deep Sequencing of Caulobacter crescentus under Uranium Stress Reveals Genes Essential for Detoxification and Stress Tolerance. J Bacteriol 2015. [PMID: 26195598 DOI: 10.1128/jb.00382-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED The ubiquitous aquatic bacterium Caulobacter crescentus is highly resistant to uranium (U) and facilitates U biomineralization and thus holds promise as an agent of U bioremediation. To gain an understanding of how C. crescentus tolerates U, we employed transposon (Tn) mutagenesis paired with deep sequencing (Tn-seq) in a global screen for genomic elements required for U resistance. Of the 3,879 annotated genes in the C. crescentus genome, 37 were found to be specifically associated with fitness under U stress, 15 of which were subsequently tested through mutational analysis. Systematic deletion analysis revealed that mutants lacking outer membrane transporters (rsaFa and rsaFb), a stress-responsive transcription factor (cztR), or a ppGpp synthetase/hydrolase (spoT) exhibited a significantly lower survival rate under U stress. RsaFa and RsaFb, which are homologues of TolC in Escherichia coli, have previously been shown to mediate S-layer export. Transcriptional analysis revealed upregulation of rsaFa and rsaFb by 4- and 10-fold, respectively, in the presence of U. We additionally show that rsaFa mutants accumulated higher levels of U than the wild type, with no significant increase in oxidative stress levels. Our results suggest a function for RsaFa and RsaFb in U efflux and/or maintenance of membrane integrity during U stress. In addition, we present data implicating CztR and SpoT in resistance to U stress. Together, our findings reveal novel gene targets that are key to understanding the molecular mechanisms of U resistance in C. crescentus. IMPORTANCE Caulobacter crescentus is an aerobic bacterium that is highly resistant to uranium (U) and has great potential to be used in U bioremediation, but its mechanisms of U resistance are poorly understood. We conducted a Tn-seq screen to identify genes specifically required for U resistance in C. crescentus. The genes that we identified have previously remained elusive using other omics approaches and thus provide significant insight into the mechanisms of U resistance by C. crescentus. In particular, we show that outer membrane transporters RsaFa and RsaFb, previously known as part of the S-layer export machinery, may confer U resistance by U efflux and/or by maintaining membrane integrity during U stress.
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23
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Ou HY, Kuang SN, He X, Molgora BM, Ewing PJ, Deng Z, Osby M, Chen W, Xu HH. Complete genome sequence of hypervirulent and outbreak-associated Acinetobacter baumannii strain LAC-4: epidemiology, resistance genetic determinants and potential virulence factors. Sci Rep 2015; 5:8643. [PMID: 25728466 PMCID: PMC4345345 DOI: 10.1038/srep08643] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/29/2015] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is an important human pathogen due to its multi-drug resistance. In this study, the genome of an ST10 outbreak A. baumannii isolate LAC-4 was completely sequenced to better understand its epidemiology, antibiotic resistance genetic determinants and potential virulence factors. Compared with 20 other complete genomes of A. baumannii, LAC-4 genome harbors at least 12 copies of five distinct insertion sequences. It contains 12 and 14 copies of two novel IS elements, ISAba25 and ISAba26, respectively. Additionally, three novel composite transposons were identified: Tn6250, Tn6251 and Tn6252, two of which contain resistance genes. The antibiotic resistance genetic determinants on the LAC-4 genome correlate well with observed antimicrobial susceptibility patterns. Moreover, twelve genomic islands (GI) were identified in LAC-4 genome. Among them, the 33.4-kb GI12 contains a large number of genes which constitute the K (capsule) locus. LAC-4 harbors several unique putative virulence factor loci. Furthermore, LAC-4 and all 19 other outbreak isolates were found to harbor a heme oxygenase gene (hemO)-containing gene cluster. The sequencing of the first complete genome of an ST10 A. baumannii clinical strain should accelerate our understanding of the epidemiology, mechanisms of resistance and virulence of A. baumannii.
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Affiliation(s)
- Hong-Yu Ou
- State Key Laboratory of Microbial Metabolism and School of Life Sciences &Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Shan N Kuang
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
| | - Xinyi He
- State Key Laboratory of Microbial Metabolism and School of Life Sciences &Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Brenda M Molgora
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
| | - Peter J Ewing
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism and School of Life Sciences &Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Melanie Osby
- Department of Pathology, LAC+USC Medical Center, Los Angeles, California, USA
| | - Wangxue Chen
- Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - H Howard Xu
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
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24
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Mazzon RR, Braz VS, da Silva Neto JF, do Valle Marques M. Analysis of the Caulobacter crescentus Zur regulon reveals novel insights in zinc acquisition by TonB-dependent outer membrane proteins. BMC Genomics 2014; 15:734. [PMID: 25168179 PMCID: PMC4176598 DOI: 10.1186/1471-2164-15-734] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 08/21/2014] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Intracellular zinc concentration needs to be maintained within strict limits due to its toxicity at high levels, and this is achieved by a finely regulated balance between uptake and efflux. Many bacteria use the Zinc Uptake Regulator Zur to orchestrate zinc homeostasis, but little is known regarding the transport of this metal across the bacterial outer membrane. RESULTS In this work we determined the Caulobacter crescentus Zur regulon by global transcriptional and in silico analyses. Among the genes directly repressed by Zur in response to zinc availability are those encoding a putative high affinity ABC uptake system (znuGHI), three TonB-dependent receptors (znuK, znuL and znuM) and one new putative transporter of a family not yet characterized (zrpW). Zur is also directly involved in the activation of a RND and a P-type ATPase efflux systems, as revealed by β-galactosidase and site-directed mutagenesis assays. Several genes belonging to the Fur regulon were also downregulated in the zur mutant, suggesting a putative cross-talk between Zur and Fur regulatory networks. Interestingly, a phenotypic analysis of the znuK and znuL mutants has shown that these genes are essential for growth under zinc starvation, suggesting that C. crescentus uses these TonB-dependent outer membrane transporters as key zinc scavenging systems. CONCLUSIONS The characterization of the C. crescentus Zur regulon showed that this regulator coordinates not only uptake, but also the extrusion of zinc. The uptake of zinc by C. crescentus in conditions of scarcity of this metal is highly dependent on TonB-dependent receptors, and the extrusion is mediated by an RND and P-type ATPase transport systems. The absence of Zur causes a disturbance in the dynamic equilibrium of zinc intracellular concentration, which in turn can interfere with other regulatory networks as seen for the Fur regulon.
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Affiliation(s)
| | | | | | - Marilis do Valle Marques
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av, Prof, Lineu Prestes 1374, 05508-900 São Paulo, Brazil.
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