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Research in Microbiology 2000Homologous recombination plays a critical role in maintaining gene diversification and genome stability. Fourteen Bacillus subtilis recombination gene products have been... (Review)
Review
Homologous recombination plays a critical role in maintaining gene diversification and genome stability. Fourteen Bacillus subtilis recombination gene products have been genetically characterised and classified into five different epistatic groups. At least seven other recombination genes could be predicted. Recombination gene products which define activities that help RecA to process DNA repair and recombination have been studied, but those that processed recombination intermediates into products (post-synaptic stage) await elucidation.
Topics: Bacillus subtilis; Gene Expression; Genes, Bacterial; Mutation; Recombination, Genetic; SOS Response, Genetics
PubMed: 10961463
DOI: 10.1016/s0923-2508(00)00165-0 -
FEMS Microbiology Reviews Jan 2012The Gram-positive bacterium Bacillus subtilis can initiate the process of sporulation under conditions of nutrient limitation. Here, we review some of the last 5 years... (Review)
Review
The Gram-positive bacterium Bacillus subtilis can initiate the process of sporulation under conditions of nutrient limitation. Here, we review some of the last 5 years of work in this area, with a particular focus on the decision to initiate sporulation, DNA translocation, cell-cell communication, protein localization and spore morphogenesis. The progress we describe has implications not only just for the study of sporulation but also for other biological systems where homologs of sporulation-specific proteins are involved in vegetative growth.
Topics: Bacillus subtilis; Gene Expression Regulation, Bacterial; Models, Biological; Protein Transport; Signal Transduction; Spores, Bacterial; Stress, Physiological
PubMed: 22091839
DOI: 10.1111/j.1574-6976.2011.00310.x -
Applied and Environmental Microbiology Jan 2013Bacillus subtilis can attain cellular protection against the detrimental effects of high osmolarity through osmotically induced de novo synthesis and uptake of the...
Bacillus subtilis can attain cellular protection against the detrimental effects of high osmolarity through osmotically induced de novo synthesis and uptake of the compatible solute l-proline. We have now found that B. subtilis can also exploit exogenously provided proline-containing peptides of various lengths and compositions as osmoprotectants. Osmoprotection by these types of peptides is generally dependent on their import via the peptide transport systems (Dpp, Opp, App, and DtpT) operating in B. subtilis and relies on their hydrolysis to liberate proline. The effectiveness with which proline-containing peptides confer osmoprotection varies considerably, and this can be correlated with the amount of the liberated and subsequently accumulated free proline by the osmotically stressed cell. Through gene disruption experiments, growth studies, and the quantification of the intracellular proline pool, we have identified the PapA (YqhT) and PapB (YkvY) peptidases as responsible for the hydrolysis of various types of Xaa-Pro dipeptides and Xaa-Pro-Xaa tripeptides. The PapA and PapB peptidases possess overlapping substrate specificities. In contrast, osmoprotection by peptides of various lengths and compositions with a proline residue positioned at their N terminus was not affected by defects in the PapA and PapB peptidases. Taken together, our data provide new insight into the physiology of the osmotic stress response of B. subtilis. They illustrate the flexibility of this ubiquitously distributed microorganism to effectively exploit environmental resources in its acclimatization to sustained high-osmolarity surroundings through the accumulation of compatible solutes.
Topics: Bacillus subtilis; Gene Knockout Techniques; Osmotic Pressure; Peptide Hydrolases; Peptides; Proline; Protein Transport; Proteolysis; Stress, Physiological
PubMed: 23144141
DOI: 10.1128/AEM.01934-12 -
Molecular Microbiology Aug 2014Biofilm formation is a social behaviour that generates favourable conditions for sustained survival in the natural environment. For the Gram-positive bacterium Bacillus... (Review)
Review
Biofilm formation is a social behaviour that generates favourable conditions for sustained survival in the natural environment. For the Gram-positive bacterium Bacillus subtilis the process involves the differentiation of cell fate within an isogenic population and the production of communal goods that form the biofilm matrix. Here we review recent progress in understanding the regulatory pathways that control biofilm formation and highlight developments in understanding the composition, function and structure of the biofilm matrix.
Topics: Bacillus subtilis; Bacterial Proteins; Biofilms; DNA, Bacterial; Extracellular Matrix; Gene Expression Regulation, Bacterial
PubMed: 24988880
DOI: 10.1111/mmi.12697 -
Proceedings of the National Academy of... Jan 2014Collective motion of self-propelled organisms or synthetic particles, often termed "active fluid," has attracted enormous attention in the broad scientific community...
Collective motion of self-propelled organisms or synthetic particles, often termed "active fluid," has attracted enormous attention in the broad scientific community because of its fundamentally nonequilibrium nature. Energy input and interactions among the moving units and the medium lead to complex dynamics. Here, we introduce a class of active matter--living liquid crystals (LLCs)--that combines living swimming bacteria with a lyotropic liquid crystal. The physical properties of LLCs can be controlled by the amount of oxygen available to bacteria, by concentration of ingredients, or by temperature. Our studies reveal a wealth of intriguing dynamic phenomena, caused by the coupling between the activity-triggered flow and long-range orientational order of the medium. Among these are (i) nonlinear trajectories of bacterial motion guided by nonuniform director, (ii) local melting of the liquid crystal caused by the bacteria-produced shear flows, (iii) activity-triggered transition from a nonflowing uniform state into a flowing one-dimensional periodic pattern and its evolution into a turbulent array of topological defects, and (iv) birefringence-enabled visualization of microflow generated by the nanometers-thick bacterial flagella. Unlike their isotropic counterpart, the LLCs show collective dynamic effects at very low volume fraction of bacteria, on the order of 0.2%. Our work suggests an unorthodox design concept to control and manipulate the dynamic behavior of soft active matter and opens the door for potential biosensing and biomedical applications.
Topics: Bacillus subtilis; Oxygen
PubMed: 24474746
DOI: 10.1073/pnas.1321926111 -
Scientific Reports Aug 2018Ubiquitous presence of cypermethrin as a contaminant in surface stream and soil necessitates to develop potential bioremediation methods to degrade and eliminate this...
Ubiquitous presence of cypermethrin as a contaminant in surface stream and soil necessitates to develop potential bioremediation methods to degrade and eliminate this pollutant from the environment. A cypermethrin utilizing bacterial strain (MIC, 450 ppm) was isolated from the soil of pesticide contaminated agriculture field and characterized by using polyphasic approach. On molecular basis bacterial isolate showed 98% homology with Bacillus subtilis strain 1D. Under optimized growth conditions, bacteria showed 95% degradation of cypermethrin after 15 days and the end products of cypermethrin biodegradation under aerobic conditions were cyclododecylamine, phenol, 3-(2,2-dichloroethenyl 2,2-dimethyl cyclopropane carboxylate,1-decanol,chloroacetic acid, acetic acid, cyclopentan palmitoleic acid, and decanoic acid. Amplification of esterase (700 bp) and laccase (1200 bp) genes was confirmed by PCR which showed a possible role of these enzymes in biodegradation of cypermethrin. In the presence of cypermethrin Km value(s) of both the enzymes was low than the control. A nobel cypermethrin degradation pathway followed by B. subtilis was proposed on the basis of characterization of biodegraded products of cypermethrin using GC-MS. Cypermethrin biodegradation ability of Bacillus subtilis strain 1D without producing any toxic end product reveals the potential of this organism in cleaning of pesticide contaminated soil and water.
Topics: Analysis of Variance; Bacillus subtilis; Biodegradation, Environmental; Esterases; Inactivation, Metabolic; Kinetics; Laccase; Phylogeny; Pyrethrins
PubMed: 30143738
DOI: 10.1038/s41598-018-31082-5 -
FEMS Microbiology Reviews May 2011A social behavior named cannibalism has been described during the early stages of sporulation of the Gram-positive Bacillus subtilis. This phenomenon is based on the... (Review)
Review
A social behavior named cannibalism has been described during the early stages of sporulation of the Gram-positive Bacillus subtilis. This phenomenon is based on the heterogeneity of sporulating populations, constituted by at least two cell types: (1) sporulating cells, in which the master regulator of sporulation Spo0A is active, and (2) nonsporulating cells, in which Spo0A is inactive. Sporulating cells produce two toxins that act cooperatively to kill the nonsporulating sister cells. The nutrients released by the dead cells into the starved medium are used for growth by the sporulating cells that are not yet fully committed to sporulate, and as a result, sporulation is arrested. This review outlines the molecular mechanisms of the killing and immunity to the toxins, the regulation of their production and other examples of killing of siblings in microorganisms. The biological significance of this behavior is discussed.
Topics: Bacillus subtilis; Gene Expression Regulation, Bacterial; Spores, Bacterial
PubMed: 20955377
DOI: 10.1111/j.1574-6976.2010.00253.x -
Molekuliarnaia Biologiia 2020Bacillus subtilis bacteria play an important role in veterinary medicine, medicine, and biotechnology, and the permanently growing demand for biotechnological products... (Review)
Review
Bacillus subtilis bacteria play an important role in veterinary medicine, medicine, and biotechnology, and the permanently growing demand for biotechnological products fuels the improvement of the properties of biotechnological strains. B. subtilis strains with improved characteristics maybe obtained by rational design and the directed evolution technologies, or be found among newly described strains. In the course of the long-term microbiome composition studies in the Russian segment of the International Space Station, the B. subtilis 20 strain was isolated, this strain shows the capacity for rapid growth and considerable biomass accumulation, as well as increased resistance to acidification of the environment in comparison to the "terrestrial" B. subtilis 168 strain. What is more, B. subtilis 20 is hyperresistant to the DNA and protein damaging factors that are linked to the overexpression of the genes controlling DNA repair, hydrogen sulfide production, and reactive oxygen species neutralization. The described properties of B. subtilis 20 are indicative of its considerable potential as a promising producer of biologically active compounds.
Topics: Bacillus subtilis; Biotechnology
PubMed: 32163397
DOI: 10.31857/S0026898420010085 -
Nature Microbiology Jan 2018Bacterial cell-cell signalling, or quorum sensing, is characterized by the secretion and groupwide detection of small diffusible signal molecules called autoinducers....
Bacterial cell-cell signalling, or quorum sensing, is characterized by the secretion and groupwide detection of small diffusible signal molecules called autoinducers. This mechanism allows cells to coordinate their behaviour in a density-dependent manner. A quorum-sensing cell may directly respond to the autoinducers it produces in a cell-autonomous and quorum-independent manner, but the strength of this self-sensing effect and its impact on bacterial physiology are unclear. Here, we explore the existence and impact of self-sensing in the Bacillus subtilis ComQXP and Rap-Phr quorum-sensing systems. By comparing the quorum-sensing response of autoinducer-secreting and non-secreting cells in co-culture, we find that secreting cells consistently show a stronger response than non-secreting cells. Combining genetic and quantitative analyses, we demonstrate this effect to be a direct result of self-sensing and rule out an indirect regulatory effect of the autoinducer production genes on response sensitivity. In addition, self-sensing in the ComQXP system affects persistence to antibiotic treatment. Together, these findings indicate the existence of self-sensing in the two most common designs of quorum-sensing systems of Gram-positive bacteria.
Topics: Ampicillin; Anti-Bacterial Agents; Bacillus subtilis; Bacterial Proteins; Coculture Techniques; Drug Resistance, Bacterial; Feedback, Physiological; Gene Expression Regulation, Bacterial; Mutation; Quorum Sensing; Signal Transduction
PubMed: 29038467
DOI: 10.1038/s41564-017-0044-z -
Journal of Bacteriology Apr 2019Bacteria deploy global programs of gene expression, including components of the SOS response, to counteract the cytotoxic and genotoxic effects of environmental...
Bacteria deploy global programs of gene expression, including components of the SOS response, to counteract the cytotoxic and genotoxic effects of environmental DNA-damaging factors. Here we report that genetic damage promoted by hexavalent chromium elicited the SOS response in , as evidenced by the induction of transcriptional , , and P fusions. Accordingly, strains deficient in homologous recombination (RecA) and nucleotide excision repair (NER) (UvrA), components of the SOS response, were significantly more sensitive to Cr(VI) treatment than were cells of the wild-type strain. These results strongly suggest that Cr(VI) induces the formation in growing cells of cytotoxic and genotoxic bulky DNA lesions that are processed by RecA and/or the NER pathways. In agreement with this notion, Cr(VI) significantly increased the formation of DNA-protein cross-links (DPCs) and induced mutagenesis in - and -deficient strains, through a pathway that required YqjH/YqjW-mediated translesion synthesis. We conclude that Cr(VI) promotes mutagenesis and cell death in by a mechanism that involves the formation of DPCs and that such deleterious effects are counteracted by both the NER and homologous recombination pathways, belonging to the RecA-dependent SOS system. It has been shown that, following permeation of cell barriers, Cr(VI) kills cells following a mechanism of reactive oxygen species-promoted DNA damage, which is counteracted by the guanine oxidized repair system. Here we report a distinct mechanism of Cr(VI)-promoted DNA damage that involves production of DPCs capable of eliciting the bacterial SOS response. We also report that the NER and homologous recombination (RecA) repair pathways, as well as low-fidelity DNA polymerases, counteract this metal-induced mechanism of killing in Hence, our results contribute to an understanding of how environmental pollutants activate global programs of gene expression that allow bacteria to contend with the cytotoxic and genotoxic effects of heavy metals.
Topics: Bacillus subtilis; Chromium; DNA Damage; DNA Repair; Mutagens; Rec A Recombinases; SOS Response, Genetics
PubMed: 30745368
DOI: 10.1128/JB.00073-19