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Narunsky A, Higgs GA, Torres BM, Yu D, de Andrade GB, Kavita K, Breaker RR. The discovery of novel noncoding RNAs in 50 bacterial genomes. Nucleic Acids Res 2024; 52:5152-5165. [PMID: 38647067 PMCID: PMC11109978 DOI: 10.1093/nar/gkae248] [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: 10/12/2023] [Revised: 03/20/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024] Open
Abstract
Structured noncoding RNAs (ncRNAs) contribute to many important cellular processes involving chemical catalysis, molecular recognition and gene regulation. Few ncRNA classes are broadly distributed among organisms from all three domains of life, but the list of rarer classes that exhibit surprisingly diverse functions is growing. We previously developed a computational pipeline that enables the near-comprehensive identification of structured ncRNAs expressed from individual bacterial genomes. The regions between protein coding genes are first sorted based on length and the fraction of guanosine and cytidine nucleotides. Long, GC-rich intergenic regions are then examined for sequence and structural similarity to other bacterial genomes. Herein, we describe the implementation of this pipeline on 50 bacterial genomes from varied phyla. More than 4700 candidate intergenic regions with the desired characteristics were identified, which yielded 44 novel riboswitch candidates and numerous other putative ncRNA motifs. Although experimental validation studies have yet to be conducted, this rate of riboswitch candidate discovery is consistent with predictions that many hundreds of novel riboswitch classes remain to be discovered among the bacterial species whose genomes have already been sequenced. Thus, many thousands of additional novel ncRNA classes likely remain to be discovered in the bacterial domain of life.
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Affiliation(s)
- Aya Narunsky
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Gadareth A Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Blake M Torres
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Gabriel Belem de Andrade
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06511, USA
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2
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Melville KT, Kamran M, Yao J, Costa M, Holland M, Taylor NL, Fritz G, Flematti GR, Waters MT. Perception of butenolides by Bacillus subtilis via the α/β hydrolase RsbQ. Curr Biol 2024; 34:623-631.e6. [PMID: 38183985 DOI: 10.1016/j.cub.2023.12.035] [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: 09/15/2023] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 01/08/2024]
Abstract
The regulation of behavioral and developmental decisions by small molecules is common to all domains of life. In plants, strigolactones and karrikins are butenolide growth regulators that influence several aspects of plant growth and development, as well as interactions with symbiotic fungi.1,2,3 DWARF14 (D14) and KARRIKIN INSENSITIVE2 (KAI2) are homologous enzyme-receptors that perceive strigolactones and karrikins, respectively, and that require hydrolase activity to effect signal transduction.4,5,6,7 RsbQ, a homolog of D14 and KAI2 from the gram-positive bacterium Bacillus subtilis, regulates growth responses to nutritional stress via the alternative transcription factor SigmaB (σB).8,9 However, the molecular function of RsbQ is unknown. Here, we show that RsbQ perceives butenolide compounds that are bioactive in plants. RsbQ is thermally destabilized by the synthetic strigolactone GR24 and its desmethyl butenolide equivalent dGR24. We show that, like D14 and KAI2, RsbQ is a functional butenolide hydrolase that undergoes covalent modification of the catalytic histidine residue. Exogenous application of both GR24 and dGR24 inhibited the endogenous signaling function of RsbQ in vivo, with dGR24 being 10-fold more potent. Application of dGR24 to B. subtilis phenocopied loss-of-function rsbQ mutations and led to a significant downregulation of σB-regulated transcripts. We also discovered that exogenous butenolides promoted the transition from planktonic to biofilm growth. Our results suggest that butenolides may serve as inter-kingdom signaling compounds between plants and bacteria to help shape rhizosphere communities.
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Affiliation(s)
- Kim T Melville
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Muhammad Kamran
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Jiaren Yao
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Marianne Costa
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Madeleine Holland
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Nicolas L Taylor
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia; Institute of Agriculture, The University of Western Australia, Perth WA 6009, Australia
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Gavin R Flematti
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia
| | - Mark T Waters
- School of Molecular Sciences, The University of Western Australia, Perth WA 6009, Australia.
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3
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Valencia-Marin MF, Chávez-Avila S, Guzmán-Guzmán P, Orozco-Mosqueda MDC, de Los Santos-Villalobos S, Glick BR, Santoyo G. Survival strategies of Bacillus spp. in saline soils: Key factors to promote plant growth and health. Biotechnol Adv 2024; 70:108303. [PMID: 38128850 DOI: 10.1016/j.biotechadv.2023.108303] [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: 08/16/2023] [Revised: 11/16/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Soil salinity is one of the most important abiotic factors that affects agricultural production worldwide. Because of saline stress, plants face physiological changes that have negative impacts on the various stages of their development, so the employment of plant growth-promoting bacteria (PGPB) is one effective means to reduce such toxic effects. Bacteria of the Bacillus genus are excellent PGPB and have been extensively studied, but what traits makes them so extraordinary to adapt and survive under harsh situations? In this work we review the Bacillus' innate abilities to survive in saline stressful soils, such as the production osmoprotectant compounds, antioxidant enzymes, exopolysaccharides, and the modification of their membrane lipids. Other survival abilities are also discussed, such as sporulation or a reduced growth state under the scope of a functional interaction in the rhizosphere. Thus, the most recent evidence shows that these saline adaptive activities are important in plant-associated bacteria to potentially protect, direct and indirect plant growth-stimulating activities. Additionally, recent advances on the mechanisms used by Bacillus spp. to improve the growth of plants under saline stress are addressed, including genomic and transcriptomic explorations. Finally, characterization and selection of Bacillus strains with efficient survival strategies are key factors in ameliorating saline problems in agricultural production.
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Affiliation(s)
- María F Valencia-Marin
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Salvador Chávez-Avila
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Paulina Guzmán-Guzmán
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Ma Del Carmen Orozco-Mosqueda
- Departamento de Ingeniería Bioquímica y Ambiental, Tecnológico Nacional de México en Celaya, 38010 Celaya, Gto, Mexico
| | | | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico.
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4
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Concepción A, Ricardo A, Enrique SL. Biodegradation of Choline NTF 2 by Pantoea agglomerans in Different Osmolarity. Characterization and Environmental Implications of the Produced Exopolysaccharide. Polymers (Basel) 2023; 15:3974. [PMID: 37836024 PMCID: PMC10575057 DOI: 10.3390/polym15193974] [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: 08/31/2023] [Revised: 09/24/2023] [Accepted: 09/30/2023] [Indexed: 10/15/2023] Open
Abstract
A specific microorganism, Pantoea agglomerans uam8, was isolated from the ionic liquid (IL) Choline NTF2 and identified by molecular biology. A biodegradation study was performed at osmolarity conditions (0.2, 0.6, 1.0 M). These had an important influence on the growth of the strain, exopolysaccharide (EPS) production, and biodegradation (1303 mg/L max production and 80% biodegradation at 0.6 M). These conditions also had an important influence on the morphology of the strain and its EPSs, but not in the chemical composition. The EPS (glucose, mannose and galactose (6:0.5:2)) produced at 0.6 M was further characterized using different techniques. The obtained EPSs presented important differences in the behavior of the emulsifying activity for vegetable oils (olive (86%), sunflower (56%) and coconut (90%)) and hydrocarbons (diesel (62%), hexane (60%)), and were compared with commercial emulsifiers. The EPS produced at 0.6 M had the highest emulsifying activity overall. This EPS did not show cytotoxicity against the tested cell line (<20%) and presented great advantages as an antioxidant (1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) (85%), hydroxyl radical (OH) (99%), superoxide anion (O2-) (94%), chelator (54%), and antimicrobial product (15 mm). The osmolarity conditions directly affected the capacity of the strain to biodegrade IL and the subsequently produced EPS. Furthermore, the EPS produced at 0.6 M has potential for environmental applications, such as the removal of hazardous materials by emulsification, whilst resulting in positive health effects such as antioxidant activity and non-toxicity.
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Affiliation(s)
- Abrusci Concepción
- Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, UAM, Cantoblanco, 28049 Madrid, Spain (S.-L.E.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Amils Ricardo
- Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, UAM, Cantoblanco, 28049 Madrid, Spain (S.-L.E.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Sánchez-León Enrique
- Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, UAM, Cantoblanco, 28049 Madrid, Spain (S.-L.E.)
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Harpke M, Kothe E. Biofilm formation in Gram-positives as an answer to combined salt and metal stress. J Basic Microbiol 2023. [PMID: 37189214 DOI: 10.1002/jobm.202300149] [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: 03/22/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/17/2023]
Abstract
Biofilm formation can lead to tolerance against stressors like antibiotics, toxic metals, salts, and other environmental contaminants. Halo- and metal-tolerant bacilli and actinomycete strains isolated from a former uranium mining and milling site in Germany were shown to form biofilm in response to salt and metal treatment; specifically, Cs and Sr exposition led to biofilm formation. Since the strains were obtained from soil samples, a more structured environment was tested using expanded clay to provide porous structures resembling the natural environment. There, accumulation of Cs could be shown for Bacillus sp. SB53B, and high Sr accumulation ranging from 75% to 90% was seen with all isolates tested. We could, therefore, show that biofilms in a structured environment like soil will contribute to the water purification obtained by the passage of water through the critical zone of soil, providing an ecosystem benefit that can hardly be overestimated.
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Affiliation(s)
- Marie Harpke
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Erika Kothe
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
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6
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Whole-Genome Sequence of Lactiplantibacillus plantarum Mut-3, Isolated from Indonesian Fermented Soybean (Tempeh). Microbiol Resour Announc 2023; 12:e0051322. [PMID: 36840600 PMCID: PMC10019267 DOI: 10.1128/mra.00513-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Lactiplantibacillus plantarum Mut-3 was isolated from tempeh. After whole-genome sequencing, analysis of its possibility as a probiotic candidate was performed using subsystem analysis with RAST with the SEED viewer.
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7
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Ye Z, Huang L, Zhao Q, Zhang W, Zhang L. Key genes for arsenobetaine synthesis in marine medaka (Oryzias melastigma) by transcriptomics. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 253:106349. [PMID: 36395554 DOI: 10.1016/j.aquatox.2022.106349] [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: 10/04/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
Marine fish undergo detoxification to overcome As stress, forming non-toxic metabolites arsenobetaine (AsB). Genes associated with AsB synthesis remain unknown. Therefore, in this study, we explored the key genes involved in the synthesis of AsB by transcriptomic analysis in marine medaka (Oryzias melastigma), and then screened candidate genes related to AsB synthesis. In the liver, 40 genes were up-regulated and 23 genes were down-regulated, whereas in muscle, 83 genes were up-regulated and 331 genes were down-regulated. We revealed that bhmt, mat2aa, and gstt1a can play a significant role in the glutathione and methionine metabolic pathway. These three genes can affect the conversion of arsenocholine (AsC) to AsB by the vitro gene transformation experiments of E. coli BL21(DE3). E. coli BL21-bhmt overexpressing bhmt resulted in more oxidation of precursor AsC to AsB. Furthermore, the AsB concentration was decreased after E. coli BL21 overexpressing mat2aa and gstt1a, which were down-regulated in marine medaka. Therefore, we concluded that bhmt, mat2aa, and gstt1a are involved in AsB synthesis. Overall, this is the first report on transcriptome screening and identification of key genes for AsB synthesis in marine medaka. We provided important insights to reveal the mystery of AsB synthesis in marine fish.
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Affiliation(s)
- Zijun Ye
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Liping Huang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Qianyu Zhao
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Wei Zhang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
| | - Li Zhang
- Key laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
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8
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Salam LB, Obayori OS. Functional characterization of the ABC transporters and transposable elements of an uncultured Paracoccus sp. recovered from a hydrocarbon-polluted soil metagenome. Folia Microbiol (Praha) 2022; 68:299-314. [PMID: 36329216 DOI: 10.1007/s12223-022-01012-0] [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: 06/28/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Environmental microorganisms usually exhibit a high level of genomic plasticity and metabolic versatility that allow them to be well-adapted to diverse environmental challenges. This study used shotgun metagenomics to decipher the functional and metabolic attributes of an uncultured Paracoccus recovered from a polluted soil metagenome and determine whether the detected attributes are influenced by the nature of the polluted soil. Functional and metabolic attributes of the uncultured Paracoccus were elucidated via functional annotation of the open reading frames (ORFs) of its contig. Functional tools deployed for the analysis include KEGG, KEGG KofamKOALA, Clusters of Orthologous Groups of proteins (COG), Comprehensive Antibiotic Resistance Database (CARD), and the Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT V6) for antibiotic resistance genes, TnCentral for transposable element, Transporter Classification Database (TCDB) for transporter genes, and FunRich for gene enrichment analysis. Analyses revealed the preponderance of ABC transporter genes responsible for the transport of oligosaccharides (malK, msmX, msmK, lacK, smoK, aglK, togA, thuK, treV, msiK), monosaccharides (glcV, malK, rbsC, rbsA, araG, ytfR, mglA), amino acids (thiQ, ynjD, thiZ, glnQ, gluA, gltL, peb1C, artP, aotP, bgtA, artQ, artR), and several others. Also detected are transporter genes for inorganic/organic nutrients like phosphate/phosphonate, nitrate/nitrite/cyanate, sulfate/sulfonate, bicarbonate, and heavy metals such as nickel/cobalt, molybdate/tungstate, and iron, among others. Antibiotic resistance genes that mediate efflux, inactivation, and target protection were detected, while transposable elements carrying resistance phenotypes for antibiotics and heavy metals were also annotated. The findings from this study have established the resilience, adaptability, and survivability of the uncultured Paracoccus in the hydrocarbon-polluted soil.
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Affiliation(s)
- Lateef Babatunde Salam
- Department of Biological Sciences, Microbiology Unit, Elizade University, Ilara-Mokin, Ondo State, Nigeria.
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Shamim A, Sanka Loganathachetti D, Chandran S, Masmoudi K, Mundra S. Salinity of irrigation water selects distinct bacterial communities associated with date palm (Phoenix dactylifera L.) root. Sci Rep 2022; 12:12733. [PMID: 35882908 PMCID: PMC9325759 DOI: 10.1038/s41598-022-16869-x] [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: 02/10/2022] [Accepted: 07/18/2022] [Indexed: 01/18/2023] Open
Abstract
Saline water irrigation has been used in date palm (Phoenix dactylifera L.) agriculture as an alternative to non-saline water due to water scarcity in hyper-arid environments. However, the knowledge pertaining to saline water irrigation impact on the root-associated bacterial communities of arid agroecosystems is scarce. In this study, we investigated the effect of irrigation sources (non-saline freshwater vs saline groundwater) on date palm root-associated bacterial communities using 16S rDNA metabarcoding. The bacterial richness, Shannon diversity and evenness didn’t differ significantly between the irrigation sources. Soil electrical conductivity (EC) and irrigation water pH were negatively related to Shannon diversity and evenness respectively, while soil organic matter displayed a positive correlation with Shannon diversity. 40.5% of total Operational Taxonomic Units were unique to non-saline freshwater irrigation, while 26% were unique to saline groundwater irrigation. The multivariate analyses displayed strong structuring of bacterial communities according to irrigation sources, and both soil EC and irrigation water pH were the major factors affecting bacterial communities. The genera Bacillus, Micromonospora and Mycobacterium were dominated while saline water irrigation whereas contrasting pattern was observed for Rhizobium, Streptomyces and Acidibacter. Taken together, we suggest that date-palm roots select specific bacterial taxa under saline groundwater irrigation, which possibly help in alleviating salinity stress and promote growth of the host plant.
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Affiliation(s)
- Azra Shamim
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al-Ain, Abu-Dhabi, UAE
| | | | - Subha Chandran
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, Abu-Dhabi, UAE
| | - Khaled Masmoudi
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al-Ain, Abu-Dhabi, UAE.
| | - Sunil Mundra
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, Abu-Dhabi, UAE. .,Khalifa Center for Genetic Engineering and Biotechnology, United Arab Emirates University, Al-Ain, United Arab Emirates.
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10
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Qin X, Xu J, Yin D, Feng F, Zeng X, Niu B, Hu X. Dehydrozaluzanin C, a novel type of anti-bacterial agent which targets transporting proteins, Opp and OpuC. Genes Dis 2022; 9:830-832. [PMID: 35685461 PMCID: PMC9170607 DOI: 10.1016/j.gendis.2021.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/28/2021] [Accepted: 11/14/2021] [Indexed: 11/27/2022] Open
Affiliation(s)
- Xiangyang Qin
- Department of Chemistry, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi 710032, PR China
| | - Jinmei Xu
- Department of Transfusion Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, PR China
| | - Dandan Yin
- Department of Hematology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, PR China
| | - Fan Feng
- Division of Digestive Surgery, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xian, Shaanxi 710032, PR China
| | - Xianfei Zeng
- School of Medicine, Northwest University, Xi'an, Shaanxi 710069, PR China
- Xi'an Area Medical Laboratory Center, Xi'an, Shaanxi 710000, PR China
| | - Bing Niu
- School of Life Sciences, Shanghai University, Shanghai 200444, PR China
| | - Xingbin Hu
- Department of Transfusion Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, PR China
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Abstract
Members of candidate Asgardarchaeota superphylum appear to share numerous eukaryotic-like attributes thus being broadly explored for their relevance to eukaryogenesis. On the contrast, the ecological roles of Asgard archaea remains understudied. Asgard archaea have been frequently associated to low-oxygen aquatic sedimentary environments worldwide spanning a broad but not extreme salinity range. To date, the available information on diversity and potential biogeochemical roles of Asgardarchaeota mostly sourced from marine habitats and to a much lesser extend from true saline environments (i.e., > 3% w/v total salinity). Here, we provide an overview on diversity and ecological implications of Asgard archaea distributed across saline environments and briefly explore their metagenome-resolved potential for osmoadaptation. Loki-, Thor- and Heimdallarchaeota are the dominant Asgard clades in saline habitats where they might employ anaerobic/microaerophilic organic matter degradation and autotrophic carbon fixation. Homologs of primary solute uptake ABC transporters seemingly prevail in Thorarchaeota, whereas those putatively involved in trehalose and ectoine biosynthesis were mostly inferred in Lokiarchaeota. We speculate that Asgardarchaeota might adopt compatible solute-accumulating ('salt-out') strategy as response to salt stress. Our current understanding on the distribution, ecology and salt-adaptive strategies of Asgardarchaeota in saline environments are, however, limited by insufficient sampling and incompleteness of the available metagenome-assembled genomes. Extensive sampling combined with 'omics'- and cultivation-based approaches seem, therefore, crucial to gain deeper knowledge on this particularly intriguing archaeal lineage.
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12
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Brantl S, Müller P. Cis- and Trans-Encoded Small Regulatory RNAs in Bacillus subtilis. Microorganisms 2021; 9:microorganisms9091865. [PMID: 34576762 PMCID: PMC8464778 DOI: 10.3390/microorganisms9091865] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Small regulatory RNAs (sRNAs) that act by base-pairing are the most abundant posttranscriptional regulators in all three kingdoms of life. Over the past 20 years, a variety of approaches have been employed to discover chromosome-encoded sRNAs in a multitude of bacterial species. However, although largely improved bioinformatics tools are available to predict potential targets of base-pairing sRNAs, it is still challenging to confirm these targets experimentally and to elucidate the mechanisms as well as the physiological role of their sRNA-mediated regulation. Here, we provide an overview of currently known cis- and trans-encoded sRNAs from B. subtilis with known targets and defined regulatory mechanisms and on the potential role of RNA chaperones that are or might be required to facilitate sRNA regulation in this important Gram-positive model organism.
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13
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Prajapati B, Bernal-Cabas M, López-Álvarez M, Schaffer M, Bartel J, Rath H, Steil L, Becher D, Völker U, Mäder U, van Dijl JM. Double trouble: Bacillus depends on a functional Tat machinery to avoid severe oxidative stress and starvation upon entry into a NaCl-depleted environment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118914. [PMID: 33245978 DOI: 10.1016/j.bbamcr.2020.118914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/08/2020] [Accepted: 11/20/2020] [Indexed: 11/17/2022]
Abstract
The widely conserved twin-arginine translocases (Tat) allow the transport of fully folded cofactor-containing proteins across biological membranes. In doing so, these translocases serve different biological functions ranging from energy conversion to cell division. In the Gram-positive soil bacterium Bacillus subtilis, the Tat machinery is essential for effective growth in media lacking iron or NaCl. It was previously shown that this phenomenon relates to the Tat-dependent export of the heme-containing peroxidase EfeB, which converts Fe2+ to Fe3+ at the expense of hydrogen peroxide. However, the reasons why the majority of tat mutant bacteria perish upon dilution in NaCl-deprived medium and how, after several hours, a sub-population adapts to this condition was unknown. Here we show that, upon growth in the absence of NaCl, the bacteria face two major problems, namely severe oxidative stress at the membrane and starvation leading to death. The tat mutant cells can overcome these challenges if they are fed with arginine, which implies that severe arginine depletion is a major cause of death and resumed arginine synthesis permits their survival. Altogether, our findings show that the Tat system of B. subtilis is needed to preclude severe oxidative stress and starvation upon sudden drops in the environmental Na+ concentration as caused by flooding or rain.
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Affiliation(s)
- Bimal Prajapati
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Margarita Bernal-Cabas
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Marina López-Álvarez
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Marc Schaffer
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Jürgen Bartel
- University of Greifswald, Institute of Microbiology, Department of Microbial Proteomics, Greifswald, Germany
| | - Hermann Rath
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Leif Steil
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Dörte Becher
- University of Greifswald, Institute of Microbiology, Department of Microbial Proteomics, Greifswald, Germany
| | - Uwe Völker
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Ulrike Mäder
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany.
| | - Jan Maarten van Dijl
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands.
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14
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Ul Haq I, Müller P, Brantl S. Intermolecular Communication in Bacillus subtilis: RNA-RNA, RNA-Protein and Small Protein-Protein Interactions. Front Mol Biosci 2020; 7:178. [PMID: 32850966 PMCID: PMC7430163 DOI: 10.3389/fmolb.2020.00178] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/09/2020] [Indexed: 11/29/2022] Open
Abstract
In bacterial cells we find a variety of interacting macromolecules, among them RNAs and proteins. Not only small regulatory RNAs (sRNAs), but also small proteins have been increasingly recognized as regulators of bacterial gene expression. An average bacterial genome encodes between 200 and 300 sRNAs, but an unknown number of small proteins. sRNAs can be cis- or trans-encoded. Whereas cis-encoded sRNAs interact only with their single completely complementary mRNA target transcribed from the opposite DNA strand, trans-encoded sRNAs are only partially complementary to their numerous mRNA targets, resulting in huge regulatory networks. In addition to sRNAs, uncharged tRNAs can interact with mRNAs in T-box attenuation mechanisms. For a number of sRNA-mRNA interactions, the stability of sRNAs or translatability of mRNAs, RNA chaperones are required. In Gram-negative bacteria, the well-studied abundant RNA-chaperone Hfq fulfils this role, and recently another chaperone, ProQ, has been discovered and analyzed in this respect. By contrast, evidence for RNA chaperones or their role in Gram-positive bacteria is still scarce, but CsrA might be such a candidate. Other RNA-protein interactions involve tmRNA/SmpB, 6S RNA/RNA polymerase, the dual-function aconitase and protein-bound transcriptional terminators and antiterminators. Furthermore, small proteins, often missed in genome annotations and long ignored as potential regulators, can interact with individual regulatory proteins, large protein complexes, RNA or the membrane. Here, we review recent advances on biological role and regulatory principles of the currently known sRNA-mRNA interactions, sRNA-protein interactions and small protein-protein interactions in the Gram-positive model organism Bacillus subtilis. We do not discuss RNases, ribosomal proteins, RNA helicases or riboswitches.
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Affiliation(s)
| | | | - Sabine Brantl
- Matthias-Schleiden-Institut, AG Bakteriengenetik, Friedrich-Schiller-Universität Jena, Jena, Germany
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15
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Warmbold B, Ronzheimer S, Freibert SA, Seubert A, Hoffmann T, Bremer E. Two MarR-Type Repressors Balance Precursor Uptake and Glycine Betaine Synthesis in Bacillus subtilis to Provide Cytoprotection Against Sustained Osmotic Stress. Front Microbiol 2020; 11:1700. [PMID: 32849357 PMCID: PMC7396694 DOI: 10.3389/fmicb.2020.01700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/29/2020] [Indexed: 02/01/2023] Open
Abstract
Bacillus subtilis adjusts to high osmolarity surroundings through the amassing of compatible solutes. It synthesizes the compatible solute glycine betaine from prior imported choline and scavenges many pre-formed osmostress protectants, including glycine betaine, from environmental sources. Choline is imported through the substrate-restricted ABC transporter OpuB and the closely related, but promiscuous, OpuC system, followed by its GbsAB-mediated oxidation to glycine betaine. We have investigated the impact of two MarR-type regulators, GbsR and OpcR, on gbsAB, opuB, and opuC expression. Judging by the position of the previously identified OpcR operator in the regulatory regions of opuB and opuC [Lee et al. (2013) Microbiology 159, 2087−2096], and that of the GbsR operator identified in the current study, we found that the closely related GbsR and OpcR repressors use different molecular mechanisms to control transcription. OpcR functions by sterically hindering access of RNA-polymerase to the opuB and opuC promoters, while GbsR operates through a roadblock mechanism to control gbsAB and opuB transcription. Loss of GbsR or OpcR de-represses opuB and opuC transcription, respectively. With respect to the osmotic control of opuB and opuC expression, we found that this environmental cue operates independently of the OpcR and GbsR regulators. When assessed over a wide range of salinities, opuB and opuC exhibit a surprisingly different transcriptional profile. Expression of opuB increases monotonously in response to incrementally increase in salinity, while opuC transcription levels decrease after an initial up-regulation at moderate salinities. Transcription of the gbsR and opcR regulatory genes is up-regulated in response to salt stress, and is also affected through auto-regulatory processes. The opuB and opuC operons have evolved through a gene duplication event. However, evolution has shaped their mode of genetic regulation, their osmotic-stress dependent transcriptional profile, and the substrate specificity of the OpuB and OpuC ABC transporters in a distinctive fashion.
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Affiliation(s)
- Bianca Warmbold
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Stefanie Ronzheimer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Sven-Andreas Freibert
- Department of Medicine, Institute for Cytobiology and Cytopathology, Philipps-University Marburg, Marburg, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Analytical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
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