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Lam NM, Tsang TF, Qu J, Tsang MW, Tao Y, Kan CH, Zou Q, Chan KH, Chu AJ, Ma C, Yang X. Development of a luciferase-based Gram-positive bacterial reporter system for the characterization of antimicrobial agents. Appl Environ Microbiol 2024:e0071724. [PMID: 39016615 DOI: 10.1128/aem.00717-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Accepted: 06/24/2024] [Indexed: 07/18/2024] Open
Abstract
Mechanistic investigations are of paramount importance in elucidating the modes of action of antibiotics and facilitating the discovery of novel drugs. We reported a luciferase-based reporter system using bacterial cells to unveil mechanisms of antimicrobials targeting transcription and translation. The reporter gene Nluc encoding NanoLuciferase (NanoLuc) was integrated into the genome of the Gram-positive model organism, Bacillus subtilis, to generate a reporter strain BS2019. Cellular transcription and translation levels were assessed by quantifying the amount of Nluc mRNA as well as the luminescence catalyzed by the enzyme NanoLuc. We validated this system using three known inhibitors of transcription (rifampicin), translation (chloramphenicol), and cell wall synthesis (ampicillin). The B. subtilis reporter strain BS2019 successfully revealed a decline in Nluc expression by rifampicin and NanoLuc enzyme activity by chloramphenicol, while ampicillin produced no observable effect. The assay was employed to characterize a previously discovered bacterial transcription inhibitor, CUHK242, with known antimicrobial activity against drug-resistant Staphylococcus aureus. Production of Nluc mRNA in our reporter BS2019 was suppressed in the presence of CUHK242, demonstrating the usefulness of the construct, which provides a simple way to study the mechanism of potential antibiotic candidates at early stages of drug discovery. The reporter system can also be modified by adopting different promoters and reporter genes to extend its scope of contribution to other fields of work. IMPORTANCE Discovering new classes of antibiotics is desperately needed to combat the emergence of multidrug-resistant pathogens. To facilitate the drug discovery process, a simple cell-based assay for mechanistic studies is essential to characterize antimicrobial candidates. In this work, we developed a luciferase-based reporter system to quantify the transcriptional and translational effects of potential compounds and validated our system using two currently marketed drugs. Reporter strains generated in this study provide readily available means for identifying bacterial transcription inhibitors as prospective novel antibacterials. We also provided a series of plasmids for characterizing promoters under various conditions such as stress.
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Affiliation(s)
- Nga Man Lam
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Tsz Fung Tsang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Jiayi Qu
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Man Wai Tsang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Yuan Tao
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Cheuk Hei Kan
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Qingyu Zou
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - King Hong Chan
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
| | - Adrian Jun Chu
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
| | - Cong Ma
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
| | - Xiao Yang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
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2
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Sharma D, Chetri PB, Ranga V, Sen S, Sarmah BK, Barooah M. Genomic analysis of acid tolerance genes and deciphering the function of ydaG gene in mitigating acid tolerance in Priestia megaterium. Front Microbiol 2024; 15:1414777. [PMID: 38966390 PMCID: PMC11222612 DOI: 10.3389/fmicb.2024.1414777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 06/10/2024] [Indexed: 07/06/2024] Open
Abstract
Adverse environmental conditions, such as acid stress, induce bacteria to employ several strategies to overcome these stressors. These strategies include forming biofilms and activating specific molecular pathways, such as the general stress response (GSR). The genome of Priestia megaterium strain G18 was sequenced using the Illumina NextSeq 500 system, resulting in a de novo assembly of 80 scaffolds. The scaffolded genome comprises 5,367,956 bp with a GC content of 37.89%, and was compared to related strains using the MiGA web server, revealing high similarity to P. megaterium NBRC 15308 and P. aryabhattai B8W22 with ANI scores of 95.4%. Phylogenetic and ribosomal multilocus sequence typing (rMLST) analyses, based on the 16S rRNA and ribosomal protein-encoding alleles, confirmed close relationships within the P. megaterium species. Functional annotation identified 5,484 protein-coding genes, with 72.31% classified into 22 COG categories, highlighting roles in amino acid transport, transcription, carbohydrate metabolism, and ribosomal structure. An in-depth genome analysis of P. megaterium G18 revealed several key genes associated with acid tolerance. Targeted inactivation of the ydaG gene from SigB regulon, a general stress response gene, significantly reduced growth under acidic conditions compared to the wild type. qRT-PCR analysis showed increased ydaG expression in acidic conditions, further supporting its role in acid stress response. Microscopic analysis revealed no morphological differences between wild-type and mutant cells, suggesting that ydaG is not involved in maintaining cellular morphology but in facilitating acid tolerance through stress protein production. This research contributes to understanding the molecular mechanisms underlying acid tolerance in soil bacteria, P. megaterium, shedding light on potential applications in agriculture and industry.
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Affiliation(s)
- Darshana Sharma
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Purna Bahadur Chetri
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Vipin Ranga
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Subhajit Sen
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Bidyut Kumar Sarmah
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Madhumita Barooah
- DBT—North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
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Sidarta M, Lorente Martín AI, Monsalve A, Marinho Righetto G, Schäfer AB, Wenzel M. Lipid phase separation impairs membrane thickness sensing by the Bacillus subtilis sensor kinase DesK. Microbiol Spectr 2024; 12:e0392523. [PMID: 38717171 DOI: 10.1128/spectrum.03925-23] [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: 11/12/2023] [Accepted: 04/08/2024] [Indexed: 06/06/2024] Open
Abstract
Membrane fluidity and thickness have emerged as crucial factors for the activity of and resistance to several antimicrobials. However, the lack of tools to study membrane fluidity and, in particular, thickness in living bacteria limits our understanding of this interplay. The Bacillus subtilis histidine kinase/phosphatase DesK is a molecular sensor that directly detects membrane thickness. It controls activity of DesR, which regulates expression of the lipid desaturase Des, known for its role in cold adaptation and daptomycin susceptibility. We hypothesized that this property could be exploited to develop biosensors and reporters for antibiotic-induced changes in membrane fluidity and thickness. To test this, we designed three assays based on the des system: activation of the Pdes promoter as reporter for membrane thickening, localization of DesK-GFP(green-fluorescent protein) as proxy for rigidified membrane domains, and antibiotic sensitivity of des, desK, and desR deletion mutants as readout for the importance of membrane rigidification/thickening under the tested condition. While we could not confirm the suitability of the des system as reporter for antibiotic-induced changes in membrane thickness, we did observe that des expression is only activated by mild temperature shocks, likely due to partitioning of the sensor DesK into fluid membrane domains upon phase separation, precluding effective thickness sensing under harsh cold shock and antibiotic stress conditions. Similarly, we did not observe any sensitivity of the deletion mutants to either temperature or antibiotic stress, raising the question to what extent the des system contributes to fluidity adaptation under these conditions. IMPORTANCE The B. subtilis des system is a prime model for direct molecular membrane thickness sensor and, as such, has been well studied in vitro. Our study shows that our understanding of its function in vivo and its importance under temperature and antibiotic stress is still very limited. Specifically, our results suggest that (i) the des system senses very subtle membrane fluidity changes that escape detection by established fluidity reporters like laurdan; (ii) membrane thickness sensing by DesK is impaired by phase separation due to partitioning of the protein into the fluid phase; and (iii) fluidity adaptations by Des are too subtle to elicit growth defects under rigidifying conditions, raising the question of how much the des system contributes to adaptation of overall membrane fluidity.
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Affiliation(s)
- Margareth Sidarta
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Ana I Lorente Martín
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Anuntxi Monsalve
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Gabriela Marinho Righetto
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Ann-Britt Schäfer
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Centre for Antibiotic Resistance Research in Gothenburg (CARe), Gothenburg, Sweden
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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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Tezuka T, Mitsuyama K, Date R, Ohnishi Y. A unique sigma/anti-sigma system in the actinomycete Actinoplanes missouriensis. Nat Commun 2023; 14:8483. [PMID: 38123564 PMCID: PMC10733313 DOI: 10.1038/s41467-023-44291-y] [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: 09/05/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
Bacteria of the genus Actinoplanes form sporangia that contain dormant sporangiospores which, upon contact with water, release motile spores (zoospores) through a process called sporangium dehiscence. Here, we set out to study the molecular mechanisms behind sporangium dehiscence in Actinoplanes missouriensis and discover a sigma/anti-sigma system with unique features. Protein σSsdA contains a functional sigma factor domain and an anti-sigma factor antagonist domain, while protein SipA contains an anti-sigma factor domain and an anti-sigma factor antagonist domain. Remarkably, the two proteins interact with each other via the anti-sigma factor antagonist domain of σSsdA and the anti-sigma factor domain of SipA. Although it remains unclear whether the SipA/σSsdA system plays direct roles in sporangium dehiscence, the system seems to modulate oxidative stress responses in zoospores. In addition, we identify a two-component regulatory system (RsdK-RsdR) that represses initiation of sporangium dehiscence.
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Affiliation(s)
- Takeaki Tezuka
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
- Graduate School of Infection Control Sciences, Kitasato University, Minato-ku, Tokyo, Japan.
| | - Kyota Mitsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Risa Date
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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6
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Fellner M, Walsh A, Dela Ahator S, Aftab N, Sutherland B, Tan EW, Bakker AT, Martin NI, van der Stelt M, Lentz CS. Biochemical and Cellular Characterization of the Function of Fluorophosphonate-Binding Hydrolase H (FphH) in Staphylococcus aureus Support a Role in Bacterial Stress Response. ACS Infect Dis 2023; 9:2119-2132. [PMID: 37824340 PMCID: PMC10644348 DOI: 10.1021/acsinfecdis.3c00246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Indexed: 10/14/2023]
Abstract
The development of new treatment options for bacterial infections requires access to new targets for antibiotics and antivirulence strategies. Chemoproteomic approaches are powerful tools for profiling and identifying novel druggable target candidates, but their functions often remain uncharacterized. Previously, we used activity-based protein profiling in the opportunistic pathogen Staphylococcus aureus to identify active serine hydrolases termed fluorophosphonate-binding hydrolases (Fph). Here, we provide the first characterization of S. aureus FphH, a conserved, putative carboxylesterase (referred to as yvaK in Bacillus subtilis) at the molecular and cellular level. First, phenotypic characterization of fphH-deficient transposon mutants revealed phenotypes during growth under nutrient deprivation, biofilm formation, and intracellular survival. Biochemical and structural investigations revealed that FphH acts as an esterase and lipase based on a fold well suited to act on a small to long hydrophobic unbranched lipid group within its substrate and can be inhibited by active site-targeting oxadiazoles. Prompted by a previous observation that fphH expression was upregulated in response to fusidic acid, we found that FphH can deacetylate this ribosome-targeting antibiotic, but the lack of FphH function did not infer major changes in antibiotic susceptibility. In conclusion, our results indicate a functional role of this hydrolase in S. aureus stress responses, and hypothetical functions connecting FphH with components of the ribosome rescue system that are conserved in the same gene cluster across Bacillales are discussed. Our atomic characterization of FphH will facilitate the development of specific FphH inhibitors and probes to elucidate its physiological role and validity as a drug target.
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Affiliation(s)
- Matthias Fellner
- Biochemistry
Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Annabel Walsh
- Biochemistry
Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Stephen Dela Ahator
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Nadia Aftab
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ben Sutherland
- Department
of Chemistry, Division of Sciences, University
of Otago, Dunedin 9054, New Zealand
| | - Eng W. Tan
- Department
of Chemistry, Division of Sciences, University
of Otago, Dunedin 9054, New Zealand
| | - Alexander T. Bakker
- Department
of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands
| | - Nathaniel I. Martin
- Biological
Chemistry Group, Institute of Biology Leiden, Leiden University, 2333
BE Leiden, The Netherlands
| | - Mario van der Stelt
- Department
of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands
| | - Christian S. Lentz
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
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Lagzian A, Riseh RS, Sarikhan S, Ghorbani A, Khodaygan P, Borriss R, Guzzi PH, Veltri P. Genome mining conformance to metabolite profile of Bacillus strains to control potato pathogens. Sci Rep 2023; 13:19095. [PMID: 37925555 PMCID: PMC10625545 DOI: 10.1038/s41598-023-46672-1] [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: 04/27/2023] [Accepted: 11/03/2023] [Indexed: 11/06/2023] Open
Abstract
Biocontrol agents are safe and effective methods for controlling plant disease pathogens, such as Fusarium solani, which causes dry wilt, and Pectobacterium spp., responsible for potato soft rot disease. Discovering agents that can effectively control both fungal and bacterial pathogens in potatoes has always presented a challenge. Biological controls were investigated using 500 bacterial strains isolated from rhizospheric microbial communities, along with two promising biocontrol strains: Pseudomonas (T17-4 and VUPf5). Bacillus velezensis (Q12 and US1) and Pseudomonas chlororaphis VUPf5 exhibited the highest inhibition of fungal growth and pathogenicity in both laboratory (48%, 48%, 38%) and greenhouse (100%, 85%, 90%) settings. Q12 demonstrated better control against bacterial pathogens in vivo (approximately 50%). Whole-genome sequencing of Q12 and US1 revealed a genome size of approximately 4.1 Mb. Q12 had 4413 gene IDs and 4300 coding sequences, while US1 had 4369 gene IDs and 4255 coding sequences. Q12 exhibited a higher number of genes classified under functional subcategories related to stress response, cell wall, capsule, levansucrase synthesis, and polysaccharide metabolism. Both Q12 and US1 contained eleven secondary metabolite gene clusters as identified by the antiSMASH and RAST servers. Notably, Q12 possessed the antibacterial locillomycin and iturin A gene clusters, which were absent in US1. This genetic information suggests that Q12 may have a more pronounced control over bacterial pathogens compared to US1. Metabolic profiling of the superior strains, as determined by LC/MS/MS, validated our genetic findings. The investigated strains produced compounds such as iturin A, bacillomycin D, surfactin, fengycin, phenazine derivatives, etc. These compounds reduced spore production and caused deformation of the hyphae in F. solani. In contrast, B. velezensis UR1, which lacked the production of surfactin, fengycin, and iturin, did not affect these structures and failed to inhibit the growth of any pathogens. Our findings suggest that locillomycin and iturin A may contribute to the enhanced control of bacterial pectolytic rot by Q12.
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Affiliation(s)
- Arezoo Lagzian
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Roohallah Saberi Riseh
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Sajjad Sarikhan
- Molecular Bank, Iranian Biological Resource Center (IBRC), ACECR, Tehran, Iran
| | - Abozar Ghorbani
- Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute, Karaj, Iran.
| | - Pejman Khodaygan
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Rainer Borriss
- Institute of Biology, Humboldt University Berlin, Berlin, Germany
| | - Pietro Hiram Guzzi
- Department of Surgical and Medical Sciences, University of Catanzaro, Catanzaro, Italy.
| | - Pierangelo Veltri
- Department of Informatics Modeling Electronics and System Engineering, University of Calabria, Calabria, Italy
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Georgalis L, Yeak KYC, Tsimpou C, Fernandez PS, Wells-Bennik M, Garre A. Disentangling the contributions of initial heterogeneities and dynamic stress adaptation to nonlinearities in bacterial survival curves. Food Res Int 2023; 173:113385. [PMID: 37803723 DOI: 10.1016/j.foodres.2023.113385] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 10/08/2023]
Abstract
The deviations from log-linearity that are often observed in bacterial survivor curves can be explained using different arguments, both biological and experimental. In this study, we used Bacillus subtilis as a model organism to demonstrate that the generally accepted vitalistic arguments (initial heterogeneities in the stress resistance of the cells in the population) may fail to describe microbial inactivation in some situations. In this sense, we showed how dynamic stress acclimation during an isothermal treatment provides an alternative explanation for survivor curves with an upwards curvature. We also provided an innovative experimental approach based on preadaptation experiments to evaluate which hypothesis is more suitable for the bacterial response. Furthermore, we used our experimental results to define bounds for the possible stress acclimation that may take place during dynamic treatments, concluding that the magnitude of stress acclimation may be larger for dynamic treatments than for isothermal experiments. We also evaluated the contribution of the SigB general stress response system to heat resistance by comparing the heat survival of wt and the ΔsigB mutant. Both strains survived better in 51, 52.5 and 55 °C when cells were pre-adapted at 48 °C than non-pre-adapted cells. However, ΔsigB was less resistant to heat than wt due to the missing SigB general stress system. Although these conclusions were based on B. subtilis as a model organism, this study can be the first step towards the development of a novel methodology able to estimate dynamic effects using only isothermal experiments. This would improve the models developed within the predictive microbiology community, improving our ability to predict microbial inactivation during industrial treatments, which are most often dynamic.
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Affiliation(s)
- Leonidas Georgalis
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | - Kah Yen Claire Yeak
- NIZO, Kernhemseweg 2, 6718 ZB Ede, the Netherlands; Food Microbiology, Wageningen University and Research, 6700 EV Wageningen, the Netherlands
| | - Christina Tsimpou
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | - Pablo S Fernandez
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain
| | | | - Alberto Garre
- Department of Agronomical Engineering & Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Murcia, Paseo Alfonso XIII, 48, 30203, Spain.
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9
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He B, Sachla AJ, Helmann JD. TerC proteins function during protein secretion to metalate exoenzymes. Nat Commun 2023; 14:6186. [PMID: 37794032 PMCID: PMC10550928 DOI: 10.1038/s41467-023-41896-1] [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: 05/08/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - Ankita J Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, NY, 14853-8101, USA.
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10
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Jun JS, Jeong HE, Moon SY, Shin SH, Hong KW. Time-Course Transcriptome Analysis of Bacillus subtilis DB104 during Growth. Microorganisms 2023; 11:1928. [PMID: 37630488 PMCID: PMC10458515 DOI: 10.3390/microorganisms11081928] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023] Open
Abstract
Bacillus subtilis DB104, an extracellular protease-deficient derivative of B. subtilis 168, is widely used for recombinant protein expression. An understanding of the changes in gene expression during growth is essential for the commercial use of bacterial strains. Transcriptome and proteome analyses are ideal methods to study the genomic response of microorganisms. In this study, transcriptome analysis was performed to monitor changes in the gene expression level of B. subtilis DB104 while growing on a complete medium. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, K-mean cluster analysis, gene ontology (GO) enrichment analysis, and the function of sigma factors were used to divide 2122 differentially expressed genes (DEGs) into 10 clusters and identified gene functions according to expression patterns. The results of KEGG pathway analysis indicated that ABC transporter is down-regulated during exponential growth and metabolic changes occur at the transition point where sporulation starts. At this point, several stress response genes were also turned on. The genes involved in the lipid catabolic process were up-regulated briefly at 15 h as an outcome of the programmed cell death that postpones sporulation. The results suggest that changes in the gene expression of B. subtilis DB104 were dependent on the initiation of sporulation. However, the expression timing of the spore coat gene was only affected by the relevant sigma factor. This study can help to understand gene expression and regulatory mechanisms in B. subtilis species by providing an overall view of transcriptional changes during the growth of B. subtilis DB104.
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Affiliation(s)
| | | | | | | | - Kwang-Won Hong
- Department of Food Science and Biotechnology, College of Life Science and Biotechnology, Dongguk University, Goyang-si 10326, Republic of Korea; (J.-S.J.); (H.-E.J.); (S.-Y.M.); (S.-H.S.)
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11
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. RESEARCH SQUARE 2023:rs.3.rs-2860473. [PMID: 37292672 PMCID: PMC10246235 DOI: 10.21203/rs.3.rs-2860473/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn2+-dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn2+-dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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12
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Kristensen SS, Diep DB, Kjos M, Mathiesen G. The role of site-2-proteases in bacteria: a review on physiology, virulence, and therapeutic potential. MICROLIFE 2023; 4:uqad025. [PMID: 37223736 PMCID: PMC10202637 DOI: 10.1093/femsml/uqad025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/21/2023] [Accepted: 05/02/2023] [Indexed: 05/25/2023]
Abstract
Site-2-proteases are a class of intramembrane proteases involved in regulated intramembrane proteolysis. Regulated intramembrane proteolysis is a highly conserved signaling mechanism that commonly involves sequential digestion of an anti-sigma factor by a site-1- and site-2-protease in response to external stimuli, resulting in an adaptive transcriptional response. Variation of this signaling cascade continues to emerge as the role of site-2-proteases in bacteria continues to be explored. Site-2-proteases are highly conserved among bacteria and play a key role in multiple processes, including iron uptake, stress response, and pheromone production. Additionally, an increasing number of site-2-proteases have been found to play a pivotal role in the virulence properties of multiple human pathogens, such as alginate production in Pseudomonas aeruginosa, toxin production in Vibrio cholerae, resistance to lysozyme in enterococci and antimicrobials in several Bacillus spp, and cell-envelope lipid composition in Mycobacterium tuberculosis. The prominent role of site-2-proteases in bacterial pathogenicity highlights the potential of site-2-proteases as novel targets for therapeutic intervention. In this review, we summarize the role of site-2-proteases in bacterial physiology and virulence, as well as evaluate the therapeutic potential of site-2-proteases.
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Affiliation(s)
- Sofie S Kristensen
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | | | - Morten Kjos
- Corresponding author. NMBU, P.O. Box 5003, 1433 Ås, Norway. E-mail:
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13
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He B, Sachla AJ, Helmann JD. TerC Proteins Function During Protein Secretion to Metalate Exoenzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536223. [PMID: 37090602 PMCID: PMC10120614 DOI: 10.1101/2023.04.10.536223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. Bacillus subtilis strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn 2+ -dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn 2+ -dependent membrane and extracellular enzymes.
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Affiliation(s)
- Bixi He
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
| | - John D. Helmann
- Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA
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Hernández-Huerta J, Tamez-Guerra P, Gomez-Flores R, Delgado-Gardea MCE, Robles-Hernández L, Gonzalez-Franco AC, Infante-Ramirez R. Pepper growth promotion and biocontrol against Xanthomonas euvesicatoria by Bacillus cereus and Bacillus thuringiensis formulations. PeerJ 2023; 11:e14633. [PMID: 36710864 PMCID: PMC9881471 DOI: 10.7717/peerj.14633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/04/2022] [Indexed: 01/25/2023] Open
Abstract
Background Bacillus genus has been used in horticultural crops as a biocontrol agent against insect pests, microbial phytopathogens, and plant growth-promoting bacteria (PGPB), representing an alternative to agrochemicals. In particular, B. cereus (Bc) and B. thuringiensis (Bt) have been studied for their fungicidal and insecticidal activities. However, their use as biofertilizer formulations and biocontrol agents against phytopathogenic bacteria is limited. Objective To evaluate Bc and Bt formulations as PGPB and biocontrol agents against the bacterial spot agent Xanthomonas euvesicatoria (Xe) in greenhouse-grown chili peppers. Methods Bc and Bt isolates obtained from soil samples were identified and characterized using conventional biochemical and multiplex PCR identification methods. Bioassays to determine Bc and Bt isolates potential as PGPB were evaluated on chili pepper seedlings in seedbeds. In addition, formulations based on Bc (F-BC26 and F-BC08) and Bt (F-BT24) strains were assessed as biofertilizers on pepper, under controlled conditions. Furthermore, in vitro antagonism assays were performed by confronting Bc and Bt isolate formulations against Xe isolates in direct (foliage) and indirect (resistance induction) phytopathogen biocontrol assays on pepper plants, which were grown under controlled conditions for 15 d after formulations treatment. Results Isolates were identified as Bc and Bt. Formulations significantly improved pepper growth in seedbeds and pots, whereas in vitro bioassays demonstrated the bactericidal effect of Bc and Bt strains against Xe isolates. Furthermore, assays showed significant plant protection by F-BC26, F-BC08, and F-BT24 formulated strains against Xe. Conclusion Results indicated that F-BT24 and F-BC26 isolates formulations promoted pepper growth and protected it against Xanthomonas euvesicatoria.
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Affiliation(s)
- Jared Hernández-Huerta
- Facultad de Ciencias Agrotecnológicas, Universidad Autónoma de Chihuahua, Chihuahua, México
| | - Patricia Tamez-Guerra
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, México
| | - Ricardo Gomez-Flores
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, México
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15
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Yeak KYC, Boekhorst J, Wels M, Abee T, Wells-Bennik MHJ. Prediction and validation of novel SigB regulon members in Bacillus subtilis and regulon structure comparison to Bacillales members. BMC Microbiol 2023; 23:17. [PMID: 36653740 PMCID: PMC9847131 DOI: 10.1186/s12866-022-02700-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 11/11/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Sigma factor B (SigB) is the central regulator of the general stress response in Bacillus subtilis and regulates a group of genes in response to various stressors, known as the SigB regulon members. Genes that are directly regulated by SigB contain a promotor binding motif (PBM) with a previously identified consensus sequence. RESULTS In this study, refined SigB PBMs were derived and different spacer compositions and lengths (N12-N17) were taken into account. These were used to identify putative SigB-regulated genes in the B. subtilis genome, revealing 255 genes: 99 had been described in the literature and 156 genes were newly identified, increasing the number of SigB putative regulon members (with and without a SigB PBM) to > 500 in B. subtilis. The 255 genes were assigned to five categories (I-V) based on their similarity to the original SigB consensus sequences. The functionalities of selected representatives per category were assessed using promoter-reporter fusions in wt and ΔsigB mutants upon exposure to heat, ethanol, and salt stress. The activity of the PrsbV (I) positive control was induced upon exposure to all three stressors. PytoQ (II) showed SigB-dependent activity only upon exposure to ethanol, whereas PpucI (II) with a N17 spacer and PylaL (III) with a N16 spacer showed mild induction regardless of heat/ethanol/salt stress. PywzA (III) and PyaaI (IV) displayed ethanol-specific SigB-dependent activities despite a lower-level conserved - 10 binding motif. PgtaB (V) was SigB-induced under ethanol and salt stress while lacking a conserved - 10 binding region. The activities of PygaO and PykaA (III) did not show evident changes under the conditions tested despite having a SigB PBM that highly resembled the consensus. The identified extended SigB regulon candidates in B. subtilis are mainly involved in coping with stress but are also engaged in other cellular processes. Orthologs of SigB regulon candidates with SigB PBMs were identified in other Bacillales genomes, but not all showed a SigB PBM. Additionally, genes involved in the integration of stress signals to activate SigB were predicted in these genomes, indicating that SigB signaling and regulon genes are species-specific. CONCLUSION The entire SigB regulatory network is sophisticated and not yet fully understood even for the well-characterized organism B. subtilis 168. Knowledge and information gained in this study can be used in further SigB studies to uncover a complete picture of the role of SigB in B. subtilis and other species.
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Affiliation(s)
- Kah Yen Claire Yeak
- grid.419921.60000 0004 0588 7915NIZO, Ede, The Netherlands ,grid.4818.50000 0001 0791 5666Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Jos Boekhorst
- grid.419921.60000 0004 0588 7915NIZO, Ede, The Netherlands ,grid.4818.50000 0001 0791 5666Host Microbe Interactomics Group, Wageningen University and Research, Wageningen, The Netherlands
| | - Michiel Wels
- grid.419921.60000 0004 0588 7915NIZO, Ede, The Netherlands ,grid.426040.4Rijk Zwaan Breeding B.V, Fijnaart, The Netherlands
| | - Tjakko Abee
- grid.4818.50000 0001 0791 5666Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands
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16
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Crystal structure and biochemical analysis suggest that YjoB ATPase is a putative substrate-specific molecular chaperone. Proc Natl Acad Sci U S A 2022; 119:e2207856119. [PMID: 36191235 PMCID: PMC9565160 DOI: 10.1073/pnas.2207856119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AAA+ ATPases are ubiquitous proteins associated with most cellular processes, including DNA unwinding and protein unfolding. Their functional and structural properties are typically determined by domains and motifs added to the conserved ATPases domain. Currently, the molecular function and structure of many ATPases remain elusive. Here, we report the crystal structure and biochemical analyses of YjoB, a Bacillus subtilis AAA+ protein. The crystal structure revealed that the YjoB hexamer forms a bucket hat-shaped structure with a porous chamber. Biochemical analyses showed that YjoB prevents the aggregation of vegetative catalase KatA and gluconeogenesis-specific glyceraldehyde-3 phosphate dehydrogenase GapB but not citrate synthase, a conventional substrate. Structural and biochemical analyses further showed that the internal chamber of YjoB is necessary for inhibition of substrate aggregation. Our results suggest that YjoB, conserved in the class Bacilli, is a potential molecular chaperone acting in the starvation/stationary phases of B. subtilis growth.
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17
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Geissler AS, Poulsen LD, Doncheva NT, Anthon C, Seemann SE, González-Tortuero E, Breüner A, Jensen LJ, Hjort C, Vinther J, Gorodkin J. The impact of PrsA over-expression on the Bacillus subtilis transcriptome during fed-batch fermentation of alpha-amylase production. Front Microbiol 2022; 13:909493. [PMID: 35992681 PMCID: PMC9386232 DOI: 10.3389/fmicb.2022.909493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
The production of the alpha-amylase (AMY) enzyme in Bacillus subtilis at a high rate leads to the accumulation of unfolded AMY, which causes secretion stress. The over-expression of the PrsA chaperone aids enzyme folding and reduces stress. To identify affected pathways and potential mechanisms involved in the reduced growth, we analyzed the transcriptomic differences during fed-batch fermentation between a PrsA over-expressing strain and control in a time-series RNA-seq experiment. We observe transcription in 542 unannotated regions, of which 234 had significant changes in expression levels between the samples. Moreover, 1,791 protein-coding sequences, 80 non-coding genes, and 20 riboswitches overlapping UTR regions of coding genes had significant changes in expression. We identified putatively regulated biological processes via gene-set over-representation analysis of the differentially expressed genes; overall, the analysis suggests that the PrsA over-expression affects ATP biosynthesis activity, amino acid metabolism, and cell wall stability. The investigation of the protein interaction network points to a potential impact on cell motility signaling. We discuss the impact of these highlighted mechanisms for reducing secretion stress or detrimental aspects of PrsA over-expression during AMY production.
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Affiliation(s)
- Adrian S. Geissler
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
| | - Line D. Poulsen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nadezhda T. Doncheva
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Christian Anthon
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
| | - Stefan E. Seemann
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
| | - Enrique González-Tortuero
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
| | | | - Lars J. Jensen
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | | | - Jeppe Vinther
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jan Gorodkin
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Jan Gorodkin,
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Dindhoria K, Kumar S, Baliyan N, Raphel S, Halami PM, Kumar R. Bacillus licheniformis MCC 2514 genome sequencing and functional annotation for providing genetic evidence for probiotic gut adhesion properties and its applicability as a bio-preservative agent. Gene 2022; 840:146744. [PMID: 35863717 DOI: 10.1016/j.gene.2022.146744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/04/2022] [Accepted: 07/14/2022] [Indexed: 11/04/2022]
Abstract
Bacillus licheniformis is a well-known probiotic that can be found in a variety of foods. The strain Bacillus licheniformis MCC 2514 was previously characterized by our group for its bio-physiological capabilities establishing it as a promising probiotic, but information on the genetic evidence for its attributes was lacking. In the current study, whole genome analysis identified the underlying molecular determinants responsible for its probiotic potential. The circular genome of MCC 2514 was 4,230,480 bp with 46.2% GC content, 24 rRNA, and 83 tRNA genes. The pangenome analysis between B. licheniformis MCC 2514 and 12 other B. licheniformis strains revealed a pangenome of 6008 genes and core genome of 3775 genes. Genome mining revealed NRPS and bacteriocins producing gene clusters indicating its biocontrol properties. Several genes encoding carbohydrate degrading enzymes, which aid in proper food degradation in the intestine, were also observed. Stress tolerance, vitamin, and essential amino acids biosynthesis related genes were found, which are important characteristics of a probiotic strain. Additionally, vital genes responsible for gut adhesion and biofilm formation were observed in its genome. The bacterium has been shown to improve the shelf life of idli batter by preventing whey separation, CO2, and odour production while maintaining the pH of 3.96-4.29, especially at cold temperatures. It has significantly reduced coliform contamination at both room and low temperatures, demonstrating its bio-preservative ability, which is also corroborated by the presence of the NRPS and bacteriocin gene clusters in its genome. The present study helped to understand both, the ability of B. licheniformis MCC 2514 to adapt the intestinal gut environment and its probiotic functionality for food preservation.
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Affiliation(s)
- Kiran Dindhoria
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Sanjeet Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
| | - Neha Baliyan
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Steji Raphel
- Department of Microbiology & Fermentation Technology, CSIR- Central Food Technological Research Institute, Mysore 570 020, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Prakash M Halami
- Department of Microbiology & Fermentation Technology, CSIR- Central Food Technological Research Institute, Mysore 570 020, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India.
| | - Rakshak Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India.
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Matavacas J, von Wachenfeldt C. Update on the Protein Homeostasis Network in Bacillus subtilis. Front Microbiol 2022; 13:865141. [PMID: 35350626 PMCID: PMC8957991 DOI: 10.3389/fmicb.2022.865141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Protein homeostasis is fundamental to cell function and survival. It relies on an interconnected network of processes involving protein synthesis, folding, post-translational modification and degradation as well as regulators of these processes. Here we provide an update on the roles, regulation and subcellular localization of the protein homeostasis machinery in the Gram-positive model organism Bacillus subtilis. We discuss emerging ideas and current research gaps in the field that, if tackled, increase our understanding of how Gram-positive bacteria, including several human pathogens, maintain protein homeostasis and cope with stressful conditions that challenge their survival.
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20
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Arias-Cartin R, Uzel A, Seduk F, Gerbaud G, Pierrel F, Broc M, Lebrun R, Guigliarelli B, Magalon A, Grimaldi S, Walburger A. Identification and characterization of a non-canonical menaquinone-linked formate dehydrogenase. J Biol Chem 2021; 298:101384. [PMID: 34748728 PMCID: PMC8808070 DOI: 10.1016/j.jbc.2021.101384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 10/25/2022] Open
Abstract
The Molybdenum/Tungsten-bispyranopterin guanine dinucleotides (Mo/W-bisPGD) family of Formate Dehydrogenases (FDHs) plays roles in several metabolic pathways ranging from carbon fixation to energy harvesting owing to their reaction with a wide variety of redox partners. Indeed, this metabolic plasticity results from the diverse structures, cofactor content, and substrates employed by partner subunits interacting with the catalytic hub. Here, we unveiled two non-canonical FDHs in Bacillus subtilis which are organized into two-subunit complexes with unique features, ForCE1 and ForCE2. We show that the ForC catalytic subunit interacts with an unprecedented partner subunit, ForE, and that its amino acid sequence within the active site deviates from the consensus residues typically associated with FDH activity, as a histidine residue is naturally substituted with a glutamine. The ForE essential subunit mediates the utilization of menaquinone as an electron acceptor as shown by the formate:menadione oxidoreductase activity of both enzymes, their copurification with menaquinone, and the distinctive detection of a protein-bound neutral menasemiquinone radical by multifrequency electron paramagnetic resonance (EPR) experiments on the purified enzymes. Moreover, EPR characterization of both FDHs reveals the presence of several [Fe-S] clusters with distinct relaxation properties and a weakly anisotropic Mo(V) EPR signature, consistent with the characteristic Mo/bisPGD cofactor of this enzyme family. Altogether, this work enlarges our knowledge of the FDH family by identifying a non-canonical FDH, which differs in terms of architecture, amino acid conservation around the Mo cofactor, and reactivity.
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Affiliation(s)
- Rodrigo Arias-Cartin
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13009 Marseille, France; Aix Marseille Université, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, 13009 Marseille, France.
| | - Alexandre Uzel
- Aix Marseille Université, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, 13009 Marseille, France
| | - Farida Seduk
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13009 Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Université, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, 13009 Marseille, France
| | - Fabien Pierrel
- Grenoble Alpes Université, CNRS, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Marianne Broc
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13009 Marseille, France
| | - Régine Lebrun
- Aix Marseille Université, CNRS, Plateforme Protéomique de l'IMM, IM2B Marseille Protéomique (MaP), 13009 Marseille, France
| | - Bruno Guigliarelli
- Aix Marseille Université, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, 13009 Marseille, France
| | - Axel Magalon
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13009 Marseille, France
| | - Stéphane Grimaldi
- Aix Marseille Université, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), IMM, IM2B, 13009 Marseille, France.
| | - Anne Walburger
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13009 Marseille, France.
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21
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Scholz AS, Baur SSM, Wolf D, Bramkamp M. An Stomatin, Prohibitin, Flotillin, and HflK/C-Domain Protein Required to Link the Phage-Shock Protein to the Membrane in Bacillus subtilis. Front Microbiol 2021; 12:754924. [PMID: 34777311 PMCID: PMC8581546 DOI: 10.3389/fmicb.2021.754924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 09/27/2021] [Indexed: 11/28/2022] Open
Abstract
Membrane surveillance and repair is of utmost importance to maintain cellular integrity and allow cellular life. Several systems detect cell envelope stress caused by antimicrobial compounds and abiotic stresses such as solvents, pH-changes and temperature in bacteria. Proteins containing an Stomatin, Prohibitin, Flotillin, and HflK/C (SPFH)-domain, including bacterial flotillins have been shown to be involved in membrane protection and membrane fluidity regulation. Here, we characterize a bacterial SPFH-domain protein, YdjI that is part of a stress induced complex in Bacillus subtilis. We show that YdjI is required to localize the ESCRT-III homolog PspA to the membrane with the help of two membrane integral proteins, YdjG/H. In contrast to classical flotillins, YdjI resides in fluid membrane regions and does not enrich in detergent resistant membrane fractions. However, similarly to FloA and FloT from B. subtilis, deletion of YdjI decreases membrane fluidity. Our data reveal a hardwired connection between phage shock response and SPFH proteins.
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Affiliation(s)
- Abigail Savietto Scholz
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sarah S. M. Baur
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Diana Wolf
- Institute of Microbiology, Technische Universität Dresden, Dresden, Germany
| | - Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
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22
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Wasselin V, Staerck C, Rincé I, Léger L, Budin-Verneuil A, Hartke A, Benachour A, Riboulet-Bisson E. Characterisation of the manganese superoxide dismutase of Enterococcus faecium. Res Microbiol 2021; 172:103876. [PMID: 34474124 DOI: 10.1016/j.resmic.2021.103876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/29/2021] [Accepted: 08/24/2021] [Indexed: 11/29/2022]
Abstract
The manganese superoxide dismutase (SodA) of E. faecium strain AUS0004 has been characterised. It is most closely related to Enterococcus hirae, Enterococcus durans, Enterococcus villorium, and Enterococcus mundtii with 100%, 91,55%, 90,85%, and 90,58% homology, respectively, but more distant from SodA of E. faecalis (81.68%). A sodA deletion mutant has been constructed. Compared to the parental strain, the ΔsodA mutant was affected in aerobic growth and more sensitive to hydrogen peroxide (H2O2), cumene hydroperoxide (CuOOH), and the superoxide anion (O2•-) generator menadione. The E. faecium strain AUS0004 is part of those bacteria accumulating H2O2 to high concentrations (around 5 mM) starting from late exponential growth phase. Accumulation of the peroxide was around 25% less in the mutant suggesting that this part of H2O2 is due to the dismutation of O2•- by SodA. The sodA gene of E. faecium AUS0004 was induced by oxygen, peroxides and menadione but the corresponding regulator remains hitherto unknown. Finally, we showed that SodA activity is important for virulence in the Galleria mellonella model.
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Affiliation(s)
- Valentin Wasselin
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Cindy Staerck
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Isabelle Rincé
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Loïc Léger
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Aurélie Budin-Verneuil
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Axel Hartke
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Abdellah Benachour
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
| | - Eliette Riboulet-Bisson
- Normandie Univ, UNICAEN U2RM-Stress and Virulence, Esplanade de la Paix, 14032 Caen, France.
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SigB regulates stress resistance, glucose starvation, MnSOD production, biofilm formation, and root colonization in Bacillus cereus 905. Appl Microbiol Biotechnol 2021; 105:5943-5957. [PMID: 34350477 DOI: 10.1007/s00253-021-11402-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/25/2021] [Accepted: 05/29/2021] [Indexed: 10/20/2022]
Abstract
Bacillus cereus 905, originally isolated from wheat rhizosphere, exhibits strong colonization ability on wheat roots. Our previous studies showed that root colonization is contributed by the ability of the bacterium to efficiently utilize carbon sources and form biofilms and that the sodA2 gene-encoded manganese-containing superoxide dismutase (MnSOD2) plays an indispensable role in the survival of B. cereus 905 in the wheat rhizosphere. In this investigation, we further demonstrated that the ability of B. cereus 905 to resist adverse environmental conditions is partially attributed to activation of the alternative sigma factor σB, encoded by the sigB gene. The sigB mutant experienced a dramatic reduction in survival when cells were exposed to ethanol, acid, heat, and oxidative stress or under glucose starvation. Analysis of the sodA2 gene transcription revealed a partial, σB-dependent induction of the gene during glucose starvation or when treated with paraquat. In addition, the sigB mutant displayed a defect in biofilm formation under stress conditions. Finally, results from the root colonization assay indicated that sigB and sodA2 collectively contribute to B. cereus 905 colonization on wheat roots. Our study suggests a diverse role of SigB in rhizosphere survival and root colonization of B. cereus 905 under stress conditions. KEY POINTS : • SigB confers resistance to environmental stresses in B. cereus 905. • SigB plays a positive role in glucose utilization and biofilm formation in B. cereus. • SigB and SodA2 collectively contribute to colonization on wheat roots by B. cereus.
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24
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Sharma M, Singh DN, Budhraja R, Sood U, Rawat CD, Adrian L, Richnow HH, Singh Y, Negi RK, Lal R. Comparative proteomics unravelled the hexachlorocyclohexane (HCH) isomers specific responses in an archetypical HCH degrading bacterium Sphingobium indicum B90A. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:41380-41395. [PMID: 33783707 DOI: 10.1007/s11356-021-13073-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Hexachlorocyclohexane (HCH) is a persistent organochlorine pesticide that poses threat to different life forms. Sphingobium indicum B90A that belong to sphingomonad is well-known for its ability to degrade HCH isomers (α-, β-, γ-, δ-), but effects of HCH isomers and adaptive mechanisms of strain B90A under HCH load remain obscure. To investigate the responses of strain B90A to HCH isomers, we followed the proteomics approach as this technique is considered as the powerful tool to study the microbial response to environmental stress. Strain B90A culture was exposed to α-, β-, γ-, δ-HCH (5 mgL-1) and control (without HCH) taken for comparison and changes in whole cell proteome were analyzed. In β- and δ-HCH-treated cultures growth decreased significantly when compared to control, α-, and γ-HCH-treated cultures. HCH residue analysis corroborated previous observations depicting the complete depletion of α- and γ-HCH, while only 66% β-HCH and 34% δ-HCH were depleted from culture broth. Comparative proteome analyses showed that β- and δ-HCH induced utmost systemic changes in strain B90A proteome, wherein stress-alleviating proteins such as histidine kinases, molecular chaperons, DNA binding proteins, ABC transporters, TonB proteins, antioxidant enzymes, and transcriptional regulators were significantly affected. Besides study confirmed constitutive expression of linA, linB, and linC genes that are crucial for the initiation of HCH isomers degradation, while increased abundance of LinM and LinN in presence of β- and δ-HCH suggested the important role of ABC transporter in depletion of these isomers. These results will help to understand the HCH-induced damages and adaptive strategies of strain B90A under HCH load which remained unravelled to date.
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Affiliation(s)
- Monika Sharma
- Fish Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | | | - Rohit Budhraja
- Helmholtz Centre for Environmental Research-UFZ, 04318, Leipzig, Germany
| | - Utkarsh Sood
- Department of Zoology, University of Delhi, Delhi, 110007, India
- The Energy and Resources Institute, Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi, 110003, India
| | - Charu Dogra Rawat
- Department of Zoology, Ramjas College, University of Delhi, Delhi, 110007, India
| | - Lorenz Adrian
- Helmholtz Centre for Environmental Research-UFZ, 04318, Leipzig, Germany
| | | | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Ram Krishan Negi
- Fish Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India.
| | - Rup Lal
- Department of Zoology, University of Delhi, Delhi, 110007, India.
- The Energy and Resources Institute, Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi, 110003, India.
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25
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Madueño L, Starevich VA, Agnello AC, Coppotelli BM, Laprida C, Vidal NC, Di Marco P, Oneto ME, Del Panno MT, Morelli IS. Assessment of Biological Contribution to Natural Recovery of Anthropized Freshwater Sediments From Argentina: Autochthonous Microbiome Structure and Functional Prediction. Front Microbiol 2021; 12:601705. [PMID: 33897628 PMCID: PMC8059475 DOI: 10.3389/fmicb.2021.601705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/01/2021] [Indexed: 11/13/2022] Open
Abstract
Monitored natural recovery (MNR) is an in situ technique of conventional remediation for the treatment of contaminated sediments that relies on natural processes to reduce the bioavailability or toxicity of contaminants. Metabarcoding and bioinformatics approaches to infer functional prediction were applied in bottom sediments of a tributary drainage channel of Río de La Plata estuary, in order to assess the biological contribution to MNR. Hydrocarbon concentration in water samples and surface sediments was below the detection limit. Surface sediments were represented with high available phosphorous, alkaline pH, and the bacterial classes Anaerolineae, Planctomycetia, and Deltaproteobacteria. The functional prediction in surface sediments showed an increase of metabolic activity, carbon fixation, methanogenesis, and synergistic relationships between Archaeas, Syntrophobacterales, and Desulfobacterales. The prediction in non-surface sediments suggested the capacity to respond to different kinds of environmental stresses (oxidative, osmotic, heat, acid pH, and heavy metals), predicted mostly in Lactobacillales order, and the capacity of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Actinomyces classes to degrade xenobiotic compounds. Canonical correspondence analysis (CCA) suggests that depth, phosphate content, redox potential, and pH were the variables that structured the bacterial community and not the hydrocarbons. The characterization of sediments by metabarcoding and functional prediction approaches, allowed to assess how the microbial activity would contribute to the recovery of the site.
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Affiliation(s)
| | | | | | | | - Cecilia Laprida
- Instituto de Estudios Andinos, CONICET/UBA, Ciudad Autónoma de Buenos Aires, Argentina
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26
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Lalanne J, Parker DJ, Li G. Spurious regulatory connections dictate the expression-fitness landscape of translation factors. Mol Syst Biol 2021; 17:e10302. [PMID: 33900014 PMCID: PMC8073009 DOI: 10.15252/msb.202110302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 12/21/2022] Open
Abstract
During steady-state cell growth, individual enzymatic fluxes can be directly inferred from growth rate by mass conservation, but the inverse problem remains unsolved. Perturbing the flux and expression of a single enzyme could have pleiotropic effects that may or may not dominate the impact on cell fitness. Here, we quantitatively dissect the molecular and global responses to varied expression of translation termination factors (peptide release factors, RFs) in the bacterium Bacillus subtilis. While endogenous RF expression maximizes proliferation, deviations in expression lead to unexpected distal regulatory responses that dictate fitness reduction. Molecularly, RF depletion causes expression imbalance at specific operons, which activates master regulators and detrimentally overrides the transcriptome. Through these spurious connections, RF abundances are thus entrenched by focal points within the regulatory network, in one case located at a single stop codon. Such regulatory entrenchment suggests that predictive bottom-up models of expression-fitness landscapes will require near-exhaustive characterization of parts.
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Affiliation(s)
- Jean‐Benoît Lalanne
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMAUSA
- Department of PhysicsMassachusetts Institute of TechnologyCambridgeMAUSA
- Present address:
Department of Genome SciencesUniversity of WashingtonSeattleWAUSA
| | - Darren J Parker
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMAUSA
- Present address:
Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Gene‐Wei Li
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMAUSA
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Tran HT, Bonilla CY. SigB-regulated antioxidant functions in gram‐positive bacteria. World J Microbiol Biotechnol 2021; 37:38. [DOI: 10.1007/s11274-021-03004-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 01/12/2021] [Indexed: 12/26/2022]
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28
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Vohradsky J, Schwarz M, Ramaniuk O, Ruiz-Larrabeiti O, Vaňková Hausnerová V, Šanderová H, Krásný L. Kinetic Modeling and Meta-Analysis of the Bacillus subtilis SigB Regulon during Spore Germination and Outgrowth. Microorganisms 2021; 9:microorganisms9010112. [PMID: 33466511 PMCID: PMC7824861 DOI: 10.3390/microorganisms9010112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 11/16/2022] Open
Abstract
The exponential increase in the number of conducted studies combined with the development of sequencing methods have led to an enormous accumulation of partially processed experimental data in the past two decades. Here, we present an approach using literature-mined data complemented with gene expression kinetic modeling and promoter sequence analysis. This approach allowed us to identify the regulon of Bacillus subtilis sigma factor SigB of RNA polymerase (RNAP) specifically expressed during germination and outgrowth. SigB is critical for the cell's response to general stress but is also expressed during spore germination and outgrowth, and this specific regulon is not known. This approach allowed us to (i) define a subset of the known SigB regulon controlled by SigB specifically during spore germination and outgrowth, (ii) identify the influence of the promoter sequence binding motif organization on the expression of the SigB-regulated genes, and (iii) suggest additional sigma factors co-controlling other SigB-dependent genes. Experiments then validated promoter sequence characteristics necessary for direct RNAP-SigB binding. In summary, this work documents the potential of computational approaches to unravel new information even for a well-studied system; moreover, the study specifically identifies the subset of the SigB regulon, which is activated during germination and outgrowth.
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Affiliation(s)
- Jiri Vohradsky
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic;
- Correspondence:
| | - Marek Schwarz
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic;
| | - Olga Ramaniuk
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (O.R.); (O.R.-L.); (V.V.H.); (H.Š.); (L.K.)
| | - Olatz Ruiz-Larrabeiti
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (O.R.); (O.R.-L.); (V.V.H.); (H.Š.); (L.K.)
- Bacterial Stress Response Research Group, Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHU, 48940 Leioa, Spain
| | - Viola Vaňková Hausnerová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (O.R.); (O.R.-L.); (V.V.H.); (H.Š.); (L.K.)
| | - Hana Šanderová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (O.R.); (O.R.-L.); (V.V.H.); (H.Š.); (L.K.)
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220 Prague, Czech Republic; (O.R.); (O.R.-L.); (V.V.H.); (H.Š.); (L.K.)
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Bonilla CY. Generally Stressed Out Bacteria: Environmental Stress Response Mechanisms in Gram-Positive Bacteria. Integr Comp Biol 2020; 60:126-133. [PMID: 32044998 DOI: 10.1093/icb/icaa002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ability to monitor the environment for toxic chemical and physical disturbances is essential for bacteria that live in dynamic environments. The fundamental sensing mechanisms and physiological responses that allow bacteria to thrive are conserved even if the molecular components of these pathways are not. The bacterial general stress response (GSR) represents a conceptual model for how one pathway integrates a wide range of environmental signals, and how a generalized system with broad molecular responses is coordinated to promote survival likely through complementary pathways. Environmental stress signals such as heat, osmotic stress, and pH changes are received by sensor proteins that through a signaling cascade activate the sigma factor, SigB, to regulate over 200 genes. Additionally, the GSR plays an important role in stress priming that increases bacterial fitness to unrelated subsequent stressors such as oxidative compounds. While the GSR response is implicated during oxidative stress, the reason for its activation remains unknown and suggests crosstalk between environmental and oxidative stress sensors and responses to coordinate antioxidant functions. Systems levels studies of cellular responses such as transcriptomes, proteomes, and metabolomes of stressed bacteria and single-cell analysis could shed light into the regulated functions that protect, remediate, and minimize damage during dynamic environments. This perspective will focus on fundamental stress sensing mechanisms and responses in Gram-positive bacterial species to illustrate their commonalities at the molecular and physiological levels; summarize exciting directions; and highlight how system-level approaches can help us understand bacterial physiology.
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Affiliation(s)
- Carla Y Bonilla
- Biology Department, Gonzaga University, 502 East Boone Avenue, Spokane, WA 99258, USA
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30
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Fujiwara K, Katagi Y, Ito K, Chiba S. Proteome-wide Capture of Co-translational Protein Dynamics in Bacillus subtilis Using TnDR, a Transposable Protein-Dynamics Reporter. Cell Rep 2020; 33:108250. [DOI: 10.1016/j.celrep.2020.108250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/03/2020] [Accepted: 09/17/2020] [Indexed: 11/29/2022] Open
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Serial Passage of Cryptococcus neoformans in Galleria mellonella Results in Increased Capsule and Intracellular Replication in Hemocytes, but Not Increased Resistance to Hydrogen Peroxide. Pathogens 2020; 9:pathogens9090732. [PMID: 32899539 PMCID: PMC7559301 DOI: 10.3390/pathogens9090732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/04/2020] [Accepted: 09/04/2020] [Indexed: 12/27/2022] Open
Abstract
To gain insight into how pathogens adapt to new hosts, Cryptococcus neoformans (H99W) was serially passaged in Galleria mellonella. The phenotypic characteristics of the passaged strain (P15) and H99W were evaluated. P15 grew faster in hemolymph than H99W, in vitro and in vivo, suggesting that adaptation had occurred. However, P15 was more susceptible to hydrogen peroxide in vitro, killed fewer mouse macrophages, and had less fungal burden in human ex vivo macrophages than H99W. Analysis of gene expression changes during Galleria infection showed only a few different genes involved in the reactive oxygen species response. As P15 sheds more GXM than H99W, P15 may have adapted by downregulating hemocyte hydrogen peroxide production, possibly through increased capsular glucuronoxylomannan (GXM) shedding. Hemocytes infected with P15 produced less hydrogen peroxide, and hydrogen peroxide production in response to GXM-shedding mutants was correlated with shed GXM. Histopathological examination of infected larvae showed increased numbers and sizes of immune nodules for P15 compared to H99W, suggesting an enhanced, but functionally defective, response to P15. These results could explain why this infection model does not always correlate with murine models. Overall, C. neoformans’ serial passage in G. mellonella resulted in a better understanding of how this yeast evolves under selection.
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32
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Ramisetty BCM, Sudhakari PA. 'Bacterial Programmed Cell Death': cellular altruism or genetic selfism? FEMS Microbiol Lett 2020; 367:5895326. [PMID: 32821912 DOI: 10.1093/femsle/fnaa141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 08/18/2020] [Indexed: 01/01/2023] Open
Abstract
Cell-dependent propagation of the 'self' is the driver of all species, organisms and even genes. Conceivably, elimination of these entities is caused by cellular death. Then, how can genes that cause the death of the same cell evolve? Programmed cell death (PCD) is the gene-dependent self-inflicted death. In multicellular organisms, PCD of a cell confers fitness to the surviving rest of the organism, which thereby allows the selection of genes responsible for PCD. However, PCD in free-living bacteria is intriguing; the death of the cell is the death of the organism. How can such PCD genes be selected in unicellular organisms? The bacterial PCD in a population is proposed to confer fitness to the surviving kin in the form of sporulation, nutrition, infection-containment and matrix materials. While the cell-centred view leading to propositions of 'altruism' is enticing, the gene-centred view of 'selfism' is neglected. In this opinion piece, we reconceptualize the PCD propositions as genetic selfism (death due to loss/mutation of selfish genes) rather than cellular altruism (death for the conferment of fitness to kin). Within the scope and the available evidence, we opine that some of the PCD-like observations in bacteria seem to be the manifestation of genetic selfism by Restriction-Modification systems and Toxin-Antitoxin systems.
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Affiliation(s)
- Bhaskar Chandra Mohan Ramisetty
- Laboratory of Molecular Biology and Evolution, 312@ASK1, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India 613401
| | - Pavithra Anantharaman Sudhakari
- Laboratory of Molecular Biology and Evolution, 312@ASK1, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India 613401
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33
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Rath H, Sappa PK, Hoffmann T, Gesell Salazar M, Reder A, Steil L, Hecker M, Bremer E, Mäder U, Völker U. Impact of high salinity and the compatible solute glycine betaine on gene expression of Bacillus subtilis. Environ Microbiol 2020; 22:3266-3286. [PMID: 32419322 DOI: 10.1111/1462-2920.15087] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/30/2020] [Accepted: 05/13/2020] [Indexed: 12/15/2022]
Abstract
The Gram-positive bacterium Bacillus subtilis is frequently exposed to hyperosmotic conditions. In addition to the induction of genes involved in the accumulation of compatible solutes, high salinity exerts widespread effects on B. subtilis physiology, including changes in cell wall metabolism, induction of an iron limitation response, reduced motility and suppression of sporulation. We performed a combined whole-transcriptome and proteome analysis of B. subtilis 168 cells continuously cultivated at low or high (1.2 M NaCl) salinity. Our study revealed significant changes in the expression of more than one-fourth of the protein-coding genes and of numerous non-coding RNAs. New aspects in understanding the impact of high salinity on B. subtilis include a sustained low-level induction of the SigB-dependent general stress response and strong repression of biofilm formation under high-salinity conditions. The accumulation of compatible solutes such as glycine betaine aids the cells to cope with water stress by maintaining physiologically adequate levels of turgor and also affects multiple cellular processes through interactions with cellular components. Therefore, we additionally analysed the global effects of glycine betaine on the transcriptome and proteome of B. subtilis and revealed that it influences gene expression not only under high-salinity, but also under standard growth conditions.
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Affiliation(s)
- Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Praveen K Sappa
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Manuela Gesell Salazar
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Leif Steil
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Michael Hecker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
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Rath H, Reder A, Hoffmann T, Hammer E, Seubert A, Bremer E, Völker U, Mäder U. Management of Osmoprotectant Uptake Hierarchy in Bacillus subtilis via a SigB-Dependent Antisense RNA. Front Microbiol 2020; 11:622. [PMID: 32373088 PMCID: PMC7186363 DOI: 10.3389/fmicb.2020.00622] [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: 12/18/2019] [Accepted: 03/19/2020] [Indexed: 01/20/2023] Open
Abstract
Under hyperosmotic conditions, bacteria accumulate compatible solutes through synthesis or import. Bacillus subtilis imports a large set of osmostress protectants via five osmotically controlled transport systems (OpuA to OpuE). Biosynthesis of the particularly effective osmoprotectant glycine betaine requires the exogenous supply of choline. While OpuB is rather specific for choline, OpuC imports a broad spectrum of compatible solutes, including choline and glycine betaine. One previously mapped antisense RNA of B. subtilis, S1290, exhibits strong and transient expression in response to a suddenly imposed salt stress. It covers the coding region of the opuB operon and is expressed from a strictly SigB-dependent promoter. By inactivation of this promoter and analysis of opuB and opuC transcript levels, we discovered a time-delayed osmotic induction of opuB that crucially depends on the S1290 antisense RNA and on the degree of the imposed osmotic stress. Time-delayed osmotic induction of opuB is apparently caused by transcriptional interference of RNA-polymerase complexes driving synthesis of the converging opuB and S1290 mRNAs. When our data are viewed in an ecophysiological framework, it appears that during the early adjustment phase of B. subtilis to acute osmotic stress, the cell prefers to initially rely on the transport activity of the promiscuous OpuC system and only subsequently fully induces opuB. Our data also reveal an integration of osmostress-specific adjustment systems with the SigB-controlled general stress response at a deeper level than previously appreciated.
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Affiliation(s)
- Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Elke Hammer
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Analytical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology e.V. (IMaB), Greifswald, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
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Ertekin O, Kutnu M, Taşkin AA, Demir M, Karataş AY, Özcengiz G. Analysis of a bac operon-silenced strain suggests pleiotropic effects of bacilysin in Bacillus subtilis. J Microbiol 2020; 58:297-313. [DOI: 10.1007/s12275-020-9064-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 12/11/2019] [Accepted: 12/24/2019] [Indexed: 11/24/2022]
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Bacillus subtilis TerC Family Proteins Help Prevent Manganese Intoxication. J Bacteriol 2020; 202:JB.00624-19. [PMID: 31685536 DOI: 10.1128/jb.00624-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/29/2019] [Indexed: 12/24/2022] Open
Abstract
Manganese (Mn) is an essential element and is required for the virulence of many pathogens. In Bacillus subtilis, Mn(II) homeostasis is regulated by MntR, a Mn(II)-responsive, DNA-binding protein. MntR serves as both a repressor of Mn(II) uptake transporters and as a transcriptional activator for expression of two cation diffusion facilitator Mn(II) efflux pumps, MneP and MneS. Mutants lacking either mntR or both mneP and mneS are extremely sensitive to Mn(II) intoxication. Using transposon mutagenesis to select suppressors of Mn(II) sensitivity, we identified YceF, a TerC family membrane protein, as capable of providing Mn(II) resistance. Another TerC paralog, YkoY, is regulated by a Mn(II)-sensing riboswitch and is partially redundant in function with YceF. YkoY is regulated in parallel with an unknown function protein YybP, also controlled by a Mn(II)-sensing riboswitch. Strains lacking between one and five of these known or putative Mn(II) tolerance proteins (MneP, MneS, YceF, YkoY, and YybP) were tested for sensitivity to Mn(II) in growth assays and for accumulation of Mn(II) using inductively coupled plasma mass spectrometry. Loss of YceF and, to a lesser extent, YkoY, sensitizes cells lacking the MneP and MneS efflux transporters to Mn(II) intoxication. This sensitivity correlates with elevated intracellular Mn(II), consistent with the suggestion that TerC proteins function in Mn(II) efflux.IMPORTANCE Manganese homeostasis is primarily regulated at the level of transport. Bacillus subtilis MntR serves as a Mn(II)-activated repressor of importer genes (mntH and mntABC) and an activator of efflux genes (mneP and mneS). Elevated intracellular Mn(II) also binds to Mn-sensing riboswitches to activate transcription of yybP and ykoY, which encodes a TerC family member. Here, we demonstrate that two TerC family proteins, YceF and YkoY, help prevent Mn(II) intoxication. TerC family proteins are widespread in bacteria and may influence host-pathogen interactions, but their effects on Mn(II) homeostasis are unclear. Our results suggest that TerC proteins work by Mn(II) export under Mn(II) overload conditions to help alleviate toxicity.
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Vinayavekhin N, Kongchai W, Piapukiew J, Chavasiri W. Aspergillus niger upregulated glycerolipid metabolism and ethanol utilization pathway under ethanol stress. Microbiologyopen 2019; 9:e00948. [PMID: 31646764 PMCID: PMC6957411 DOI: 10.1002/mbo3.948] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 09/24/2019] [Accepted: 09/27/2019] [Indexed: 11/26/2022] Open
Abstract
The knowledge of how Aspergillus niger responds to ethanol can lead to the design of strains with enhanced ethanol tolerance to be utilized in numerous industrial bioprocesses. However, the current understanding about the response mechanisms of A. niger toward ethanol stress remains quite limited. Here, we first applied a cell growth assay to test the ethanol tolerance of A. niger strain ES4, which was isolated from the wall near a chimney of an ethanol tank of a petroleum company, and found that it was capable of growing in 5% (v/v) ethanol to 30% of the ethanol‐free control level. Subsequently, the metabolic responses of this strain toward ethanol were investigated using untargeted metabolomics, which revealed the elevated levels of triacylglycerol (TAG) in the extracellular components, and of diacylglycerol, TAG, and hydroxy‐TAG in the intracellular components. Lastly, stable isotope labeling mass spectrometry with ethanol‐d6 showed altered isotopic patterns of molecular ions of lipids in the ethanol‐d6 samples, compared with the nonlabeled ethanol controls, suggesting the ability of A. niger ES4 to utilize ethanol as a carbon source. Together, the studies revealed the upregulation of glycerolipid metabolism and ethanol utilization pathway as novel response mechanisms of A. niger ES4 toward ethanol stress, thereby underlining the utility of untargeted metabolomics and the overall approaches as tools for elucidating new biological insights.
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Affiliation(s)
- Nawaporn Vinayavekhin
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,Biocatalyst and Environmental Biotechnology Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Wimonsiri Kongchai
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Jittra Piapukiew
- Biocatalyst and Environmental Biotechnology Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Warinthorn Chavasiri
- Center of Excellence in Natural Products Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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Rojas-Tapias DF, Helmann JD. Roles and regulation of Spx family transcription factors in Bacillus subtilis and related species. Adv Microb Physiol 2019; 75:279-323. [PMID: 31655740 DOI: 10.1016/bs.ampbs.2019.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bacillus subtilis Spx is the prototype for a large family of redox-responsive transcription factors found in many bacteria, most notably those from the phylum Firmicutes. Unusually for a transcription factor, B. subtilis Spx protein modulates gene expression by binding as a monomer to the αCTD domain of RNA polymerase (RNAP), and only interacts with DNA during subsequent promoter engagement. B. subtilis Spx drives the expression of a large regulon in response to proteotoxic conditions, such as heat and disulfide stress, as well as cell wall stress. Here, we review the detailed mechanisms that control the expression, stability, and activity of Spx in response to a variety of stress conditions. We also summarize current knowledge regarding Spx homologs in other Firmicutes, the environmental conditions in which those homologs are activated, and their biological role.
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Affiliation(s)
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States
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Gottschlich L, Geiser P, Bortfeld-Miller M, Field CM, Vorholt JA. Complex general stress response regulation in Sphingomonas melonis Fr1 revealed by transcriptional analyses. Sci Rep 2019; 9:9404. [PMID: 31253827 PMCID: PMC6599016 DOI: 10.1038/s41598-019-45788-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/12/2019] [Indexed: 01/31/2023] Open
Abstract
The general stress response (GSR) represents an important trait to survive in the environment by leading to multiple stress resistance. In alphaproteobacteria, the GSR is under the transcriptional control of the alternative sigma factor EcfG. Here we performed transcriptome analyses to investigate the genes controlled by EcfG of Sphingomonas melonis Fr1 and the plasticity of this regulation under stress conditions. We found that EcfG regulates genes for proteins that are typically associated with stress responses. Moreover, EcfG controls regulatory proteins, which likely fine-tune the GSR. Among these, we identified a novel negative GSR feedback regulator, termed NepR2, on the basis of gene reporter assays, phenotypic analyses, and biochemical assays. Transcriptional profiling of signaling components upstream of EcfG under complex stress conditions showed an overall congruence with EcfG-regulated genes. Interestingly however, we found that the GSR is transcriptionally linked to the regulation of motility and biofilm formation via the single domain response regulator SdrG and GSR-activating histidine kinases. Altogether, our findings indicate that the GSR in S. melonis Fr1 underlies a complex regulation to optimize resource allocation and resilience in stressful and changing environments.
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Affiliation(s)
- Lisa Gottschlich
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Petra Geiser
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Miriam Bortfeld-Miller
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Christopher M Field
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Julia A Vorholt
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland.
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40
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Sayer CV, Barat B, Popham DL. Identification of L-Valine-initiated-germination-active genes in Bacillus subtilis using Tn-seq. PLoS One 2019; 14:e0218220. [PMID: 31199835 PMCID: PMC6568419 DOI: 10.1371/journal.pone.0218220] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/28/2019] [Indexed: 11/18/2022] Open
Abstract
Bacterial endospores can survive harsh environmental conditions and long-term dormancy in the absence of nutrients, but can rapidly germinate under favorable conditions. In the present study, we employed transposon sequencing (Tn-seq) to identify genes with previously uncharacterized roles in spore germination. Identified genes that encoded spore inner membrane proteins were chosen for study of defined mutants, which exhibited delayed germination in several assays in response to varying germinants. Significantly slowed release of DPA indicated that mutants were affected in Stage I of germination. Several mutants exhibited phenotypic traits consistent with failure of a GerA germinant receptor-mediated response, while others appeared to have a more general loss of response to varied germinants. Use of a gerA-lacZ transcriptional fusion and quantitative western blotting of GerAC allowed mutants to be classified based upon normal or decreased gerA transcription and normal or reduced GerA accumulation. Fourteen genes were identified to have newly described roles within Bacillus spore germination. A more complete understanding of this process can contribute to the development of better spore decontamination procedures.
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Affiliation(s)
- Cameron V. Sayer
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States of America
| | - Bidisha Barat
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States of America
| | - David L. Popham
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States of America
- * E-mail:
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41
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Feng X, He C, Jiao L, Liang X, Zhao R, Guo Y. Analysis of differential expression proteins reveals the key pathway in response to heat stress in Alicyclobacillus acidoterrestris DSM 3922T. Food Microbiol 2019; 80:77-84. [DOI: 10.1016/j.fm.2019.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 11/12/2018] [Accepted: 01/06/2019] [Indexed: 11/27/2022]
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42
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Oren N, Raanan H, Kedem I, Turjeman A, Bronstein M, Kaplan A, Murik O. Desert cyanobacteria prepare in advance for dehydration and rewetting: The role of light and temperature sensing. Mol Ecol 2019; 28:2305-2320. [DOI: 10.1111/mec.15074] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/05/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Nadav Oren
- Department of Plant and Environmental Sciences The Hebrew University of Jerusalem Jerusalem Israel
| | - Hagai Raanan
- Department of Plant and Environmental Sciences The Hebrew University of Jerusalem Jerusalem Israel
- Environmental Biophysics and Molecular Ecology Program, Institute of Earth, Ocean and Atmospheric Sciences Rutgers University New Brunswick New Jersey
| | - Isaac Kedem
- Department of Plant and Environmental Sciences The Hebrew University of Jerusalem Jerusalem Israel
| | - Adi Turjeman
- The Center for Genomic Technologies The Hebrew University of Jerusalem Jerusalem Israel
| | - Michal Bronstein
- The Center for Genomic Technologies The Hebrew University of Jerusalem Jerusalem Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences The Hebrew University of Jerusalem Jerusalem Israel
| | - Omer Murik
- Department of Plant and Environmental Sciences The Hebrew University of Jerusalem Jerusalem Israel
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43
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Impact of Combined Acidic and Hyperosmotic Shock Conditions on the Proteome of Listeria monocytogenesATCC 19115 in a Time-Course Study. J FOOD QUALITY 2019. [DOI: 10.1155/2019/3075028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenescan cause listeriosis in humans through consumption of contaminated food and can adapt to and grow under a wide array of physiochemical stresses. Consequently, it causes persistent food safety issues and requires vigilant sanitation processes to be in place, especially for the manufacture of high-risk food products. In this study, the global proteomic responses of the food-borne pathogenL. monocytogenesstrain ATCC 19115 were determined when exposed to nonthermal inactivation. This process was examined in the early stationary growth phase with the strain placed under simultaneous exposure to low pH (pH 3.5) and high salinity (aw0.900, 14% NaCl). Proteomic responses, measured using iTRAQ techniques, were conducted over a time course (5 min, 30 min, and 1 h at 25°C). The enumeration results showed that, at 5 min, cells underwent initial rapid inactivation by 1.2 log units and 2.5 log units after 30 min, and after that, culturability remained stable when sampled at 1 h. From the iTRAQ results, the proteome level changes that occur rapidly during the inactivation process mainly affected prophage, cell defense/detoxification, carbohydrate-related metabolism, transporter proteins, phosphotransferase systems, cell wall biogenesis, and specific cell surface proteins. Pathway map analysis revealed that several pathways are affected including pentose and glucuronate interconversions, glycolysis/gluconeogenesis, pyruvate metabolism, valine, leucine and isoleucine biosynthesis, oxidative phosphorylation, and proteins associated with bacterial invasion of epithelial cells and host survival. Proteome profiling provided a better understanding of the physiological responses of this pathogen to adapt to lethal nonthermal environments and indicates the need to improve food processing and storage methods, especially for non- or minimally thermally processed foods.
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Seki T, Furumi T, Hashimoto M, Hara H, Matsuoka S. Activation of extracytoplasmic function sigma factors upon removal of glucolipids and reduction of phosphatidylglycerol content in Bacillus subtilis cells lacking lipoteichoic acid. Genes Genet Syst 2019; 94:71-80. [PMID: 30971625 DOI: 10.1266/ggs.18-00046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In Bacillus subtilis, extracytoplasmic function (ECF) sigma factors are activated by reduction of phosphatidylglycerol (PG) content, absence of glucolipids, or absence of lipoteichoic acid (LTA). LTA is synthesized by polymerization of the glycerophosphate moiety of PG onto diglucosyldiacylglycerol (DGlcDG), a major glucolipid in B. subtilis, in the plasma membrane. Thus, reduction of PG content or absence of glucolipids might cause some changes in LTA, and hence we investigated whether reduction of PG content or absence of glucolipids induces the activation of ECF sigma factors independently from an ensuing change in LTA. Disruption of ugtP, responsible for glucolipid synthesis, in cells lacking LTA caused an additive increase of activation levels of σM, σX, σV and σY (3.1-, 2.2-, 2.1- and 1.4-fold, respectively), relative to their activation levels in cells lacking LTA alone. Reduction of PG content (by repressing Pspac-pgsA) in the cells lacking LTA caused an additive increase of activation levels of σM, σW and σV (2.3-, 1.9- and 2.2-fold, respectively). These results suggested that absence of glucolipids or reduction of PG alone, not the possible secondary alteration in LTA, leads to changes that affect the regulation systems of some ECF sigma factors in the plasma membrane.
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Affiliation(s)
- Takahiro Seki
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Takuya Furumi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Michihiro Hashimoto
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Hiroshi Hara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Satoshi Matsuoka
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
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45
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Identification and Characterization of Differentially Expressed Proteins from Trichoderma harzianum During Interaction with Colletotrichum falcatum Causing Red Rot in Sugarcane. SUGAR TECH 2019. [DOI: 10.1007/s12355-019-00699-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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46
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Long X, Wang D, Zou Y, Tian J, Tian Y, Liao X. Glycine betaine enhances biodegradation of phenol in high saline environments by the halophilic strain Oceanobacillussp. PT-20. RSC Adv 2019; 9:29205-29216. [PMID: 35528440 PMCID: PMC9071815 DOI: 10.1039/c9ra05163e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/11/2019] [Indexed: 11/21/2022] Open
Abstract
Glycine betaine enhanced the biodegradation of phenol by halophilic strain PT-20 in high salinity conditions.
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Affiliation(s)
- Xiufeng Long
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Denggang Wang
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering
- South China University of Technology
- Guangzhou 510006
- PR China
| | - Yuqi Zou
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Jiewei Tian
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
| | - Yongqiang Tian
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
- National Engineering Laboratory for Clean Technology of Leather Manufacture
| | - Xuepin Liao
- Department of Biomass and Leather Engineering
- Sichuan University
- Chengdu 610065
- PR China
- National Engineering Laboratory for Clean Technology of Leather Manufacture
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47
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Schäfer H, Heinz A, Sudzinová P, Voß M, Hantke I, Krásný L, Turgay K. Spx, the central regulator of the heat and oxidative stress response in B. subtilis, can repress transcription of translation-related genes. Mol Microbiol 2018; 111:514-533. [PMID: 30480837 DOI: 10.1111/mmi.14171] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2018] [Indexed: 12/19/2022]
Abstract
Spx is a Bacillus subtilis transcription factor that interacts with the alpha subunits of RNA polymerase. It can activate the thiol stress response regulon and interfere with the activation of many developmental processes. Here, we show that Spx is a central player orchestrating the heat shock response by up-regulating relevant stress response genes as revealed by comparative transcriptomic experiments. Moreover, these experiments revealed the potential of Spx to inhibit transcription of translation-related genes. By in vivo and in vitro experiments, we confirmed that Spx can inhibit transcription from rRNA. This inhibition depended mostly on UP elements and the alpha subunits of RNA polymerase. However, the concurrent up-regulation activity of stress genes by Spx, but not the inhibition of translation related genes, was essential for mediating stress response and antibiotic tolerance under the applied stress conditions. The observed inhibitory activity might be compensated in vivo by additional stress response processes interfering with translation. Nevertheless, the impact of Spx on limiting translation becomes apparent under conditions with high cellular Spx levels. Interestingly, we observed a subpopulation of stationary phase cells that contains raised Spx levels, which may contribute to growth inhibition and a persister-like behaviour of this subpopulation during outgrowth.
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Affiliation(s)
- Heinrich Schäfer
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Anja Heinz
- Institute of Biology-Microbiology, Freie Universität Berlin, Königin-Luise-Str. 12-16, D-14195, Berlin, Germany
| | - Petra Sudzinová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague, Czech Republic
| | - Michelle Voß
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Ingo Hantke
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague, Czech Republic
| | - Kürşad Turgay
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
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48
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Gao T, Ding M, Yang CH, Fan H, Chai Y, Li Y. The phosphotransferase system gene ptsH plays an important role in MnSOD production, biofilm formation, swarming motility, and root colonization in Bacillus cereus 905. Res Microbiol 2018; 170:86-96. [PMID: 30395927 DOI: 10.1016/j.resmic.2018.10.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/24/2018] [Accepted: 10/23/2018] [Indexed: 12/30/2022]
Abstract
The rhizosphere bacterium Bacillus cereus 905 is capable of promoting plant growth through effective colonization on plant roots. The sodA2-encoding manganese-containing superoxide dismutase (MnSOD2) is important for survival of B. cereus 905 in the wheat rhizosphere. However, the genes involved in regulating sodA2 expression and the mechanisms of rhizosphere colonization of B. cereus 905 are not well elucidated. In this study, we found that the deletion of the ptsH gene, which encodes the histidine-phosphorylatable protein (HPr), a component of the phosphotransferase system (PTS), causes a decrease of about 60% in the MnSOD2 expression. Evidences indicate that the ptsH dramatically influences resistance to oxidative stress, glucose uptake, as well as biofilm formation and swarming motility of B. cereus 905. Root colonization assay demonstrated that ΔptsH is defective in colonizing wheat roots, while complementation of the sodA2 gene could partially restore the ability in utilization of arabinose, a non-PTS sugar, and root colonization caused by the loss of the ptsH gene. In toto, based on the current findings, we propose that PtsH contributes to root colonization of B. cereus 905 through multiple indistinct mechanisms, involving PTS and uptake of PTS-sugars, up-regulation of MnSOD2 production, and promotion of biofilm formation and swarming motility.
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Affiliation(s)
- Tantan Gao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China; Department of Biology, Northeastern University, 360 Huntington Avenue, Boston, MA, 02215, USA.
| | - Mingzheng Ding
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI, 53211, USA.
| | - Haiyan Fan
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
| | - Yunrong Chai
- Department of Biology, Northeastern University, 360 Huntington Avenue, Boston, MA, 02215, USA.
| | - Yan Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
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49
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Sharma AK, Leppla SH, Pomerantsev AP, Shiloach J. Effect of over expressing protective antigen on global gene transcription in Bacillus anthracis BH500. Sci Rep 2018; 8:16108. [PMID: 30382110 PMCID: PMC6208434 DOI: 10.1038/s41598-018-34196-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/08/2018] [Indexed: 01/22/2023] Open
Abstract
Protective antigen (PA) of Bacillus anthracis is being considered as a vaccine candidate against anthrax and its production has been explored in several heterologous host systems. Since the systems tested introduced adverse issues such as inclusion body formation and endotoxin contamination, the production from B. anthracis is considered as a preferred method. The present study examines the effect of PA expression on the metabolism of B. anthracis producing strain, BH500, by comparing it with a control strain carrying an empty plasmid. The strains were grown in a bioreactor and RNA-seq analysis of the producing and non-producing strain was conducted. Among the observed differences, the strain expressing rPA had increased transcription of sigL, the gene encoding RNA polymerase σ54, sigB, the general stress transcription factor gene and its regulators rsbW and rsbV, as well as the global regulatory repressor ctsR. There were also decreased expression of intracellular heat stress related genes such as groL, groES, hslO, dnaJ, and dnaK and increased expression of extracellular chaperons csaA and prsA2. Also, major central metabolism genes belonging to TCA, glycolysis, PPP, and amino acids biosynthesis were up-regulated in the PA-producing strain during the lag phase and down-regulated in the log and late-log phases, which was associated with decreased specific growth rates. The information obtained from this study may guide genetic modification of B. anthracis to improve PA production.
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Affiliation(s)
- Ashish K Sharma
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestives and Kidney Diseases (NIDDK) NIH, Maryland, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, National Institute of Allergy and Infectious diseases (NIAID), NIH, Maryland, USA
| | - Andrei P Pomerantsev
- Microbial Pathogenesis Section, National Institute of Allergy and Infectious diseases (NIAID), NIH, Maryland, USA
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestives and Kidney Diseases (NIDDK) NIH, Maryland, USA.
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Pawar S, Yao X, Lu CD. Spermine and oxacillin stress response on the cell wall synthesis and the global gene expression analysis in Methicillin-resistance Staphylococcus aureus. Genes Genomics 2018; 41:43-59. [PMID: 30229508 DOI: 10.1007/s13258-018-0735-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/30/2018] [Indexed: 10/28/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a rapidly emerging bacteria causing infection, which has developed resistance to most of the beta-lactam antibiotics because of newly acquired low-affinity penicillin-binding protein (PBP2a), which can continue to build the cell wall when beta-lactams block other PBPs. Exogenous spermine exerts a dose-dependent inhibition effect on the growth of Escherichia coli, Salmonella enterica serovar, and S. aureus. Selection of an MRSA Mu50 derivative which harbors mutation on PBP2 gene (named as MuM) showing spermine resistance and which confers a complete abolishment of spermine-beta-lactam synergy was identified. To further investigate the gene expression changes, a transcriptome profiling of MuM against Mu50 (wild-type) without any treatment, MuM and Mu50 in response to high dose spermine and Mu50 in response to spermine-beta-lactam synergy at 15, 30 and 60 min time points was performed. Functional annotation was further performed to delineate the metabolic pathways associated with the significant genes. A significant down-regulation in the iron regulatory system, potassium channel uptake and polyamine transport system with an up-regulation in general stress response sigB dependent operon in MuM strain at 15, 30 and 60 min time points with spermine treatment compared to Mu50 strain was observed. Analysis of spermine-dependent synergy with beta-lactams on cell wall synthesis revealed that it significantly reduces the degree of cross-linkage on cell wall with no change in trypsin digestion pattern of purified PBPs and without affecting PBPs expression or PBPs acylation by Bocillin. A strong relation between PBP2 protein and general stress sigB response, iron, potassium and polyamine transport systems was observed. SigB regulon should be activated on stress, which was not seen in some of our previous studies where it was down-regulated in wild-type Mu50 strain with spermine stress. Here, an intriguing finding is made where there seems to be a correction of this abnormal response of no SigB induction to a significant induction by PBP2 mutation. In MuM strain, a significant down-regulation of KdpABC operon genes at 15, 30 and 60 min time points on spermine stress is seen, which seems to be absent without spermine treatment. Since KCL has been found to protect the cell against spermine stress in wild-type strain by induction of KdpABC operon, it fails to do so in MuM strain underlying the importance of PBP2 protein in spermine stress. Analysis of spermine-dependent synergy with beta-lactams on cell wall synthesis revealed that it significantly reduces the degree of cross-linkage on cell wall with no change in trypsin digestion patterns of purified PBPs and without affecting PBPs expression or PBPs acylation by Bocillin. Furthermore, spermine does not help in enhancing the binding of beta-lactams to PBPs and binding of spermine to PBPs does not cause conformational changes to PBPs, as tested with trypsin digestion patterns. Future studies on the molecular mechanism of spermine interactions with these systems hold great potential for the development of new therapeutics for MRSA infections.
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Affiliation(s)
- Shrikant Pawar
- Department of Computer Science, Georgia State University, 33 Gilmer Street SE, Atlanta, GA, 30303, USA.,Department of Biology, Georgia State University, 33 Gilmer Street SE, Atlanta, GA, 30303, USA
| | - Xiangyu Yao
- National Institutes of Health, 9000 Center Dr, Bethesda, MD, 20892, USA
| | - Chung-Dar Lu
- Department of Clinical Laboratory and Nutritional Sciences, University of Massachusetts, Weed Hall 320, Lowell, MA, 01854-5125, USA.
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