Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.129
Filtrar
1.
Int J Mol Sci ; 22(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34639021

RESUMO

An ABA-deficient barley mutant (Az34) and its parental cultivar (Steptoe) were compared. Plants of salt-stressed Az34 (100 mmol m-3 NaCl for 10 days) grown in sand were 40% smaller than those of "Steptoe", exhibited a lower leaf relative water content and lower ABA concentrations. Rhizosphere inoculation with IB22 increased plant growth of both genotypes. IB22 inoculation raised ABA in roots of salt-stressed plants by supplying ABA exogenously and by up-regulating ABA synthesis gene HvNCED2 and down-regulating ABA catabolic gene HvCYP707A1. Inoculation partially compensated for the inherent ABA deficiency of the mutant. Transcript abundance of HvNCED2 and related HvNCED1 in the absence of inoculation was 10 times higher in roots than in shoots of both mutant and parent, indicating that ABA was mainly synthesized in roots. Under salt stress, accumulation of ABA in the roots of bacteria-treated plants was accompanied by a decline in shoot ABA suggesting bacterial inhibition of ABA transport from roots to shoots. ABA accumulation in the roots of bacteria-treated Az34 was accompanied by increased leaf hydration, the probable outcome of increased root hydraulic conductance. Thereby, we tested the hypothesis that the ability of rhizobacterium (Bacillus subtilis IB22) to modify responses of plants to salt stress depends on abscisic acid (ABA) accumulating in roots.


Assuntos
Ácido Abscísico/metabolismo , Bacillus subtilis/fisiologia , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Estresse Salino , Regulação da Expressão Gênica de Plantas , Interações entre Hospedeiro e Microrganismos/genética , Rizosfera , Simbiose
2.
Int J Mol Sci ; 22(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34639224

RESUMO

BACKGROUND: Cheonggukjang is a traditional fermented soybean paste that is mostly consumed in Korea. However, the biological activities of Cheonggukjang specific compounds have not been studied. Thus, we aimed to discover a novel dual agonist for PPARα/γ from dietary sources such as Cheonggukjang specific volatile compounds and explore the potential role of PPARα/γ dual agonists using in vitro and in silico tools. METHODS: A total of 35 compounds were selected from non-fermented and fermented soybean products cultured with Bacillus subtilis, namely Cheonggukjang, for analysis by in vitro and in silico studies. RESULTS: Molecular docking results showed that 1,3-diphenyl-2-propanone (DPP) had the lowest docking score for activating PPARα (1K7L) and PPARγ (3DZY) with non-toxic effects. Moreover, DPP significantly increased the transcriptional activities of both PPARα and PPARγ and highly activated its expression in Ac2F liver cells, in vitro. Here, we demonstrated for the first time that DPP can act as a dual agonist of PPARα/γ using in vitro and in silico tools. CONCLUSIONS: The Cheonggukjang-specific compound DPP could be a novel PPARα/γ dual agonist and it is warranted to determine the therapeutic potential of PPARα/γ activation by dietary intervention and/or supplementation in the treatment of metabolic disorders without causing any adverse effects.


Assuntos
Bacillus subtilis/fisiologia , Compostos de Bifenilo/farmacologia , Simulação por Computador , Simulação de Acoplamento Molecular , PPAR alfa/agonistas , PPAR gama/agonistas , Alimentos de Soja/microbiologia , Compostos de Bifenilo/química , Fermentação , Técnicas In Vitro
3.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502250

RESUMO

Bacillus subtilis vegetative cells switch to sporulation upon nutrient limitation. To investigate the proteome dynamics during sporulation, high-resolution time-lapse proteomics was performed in a cell population that was induced to sporulate synchronously. Here, we are the first to comprehensively investigate the changeover of sporulation regulatory proteins, coat proteins, and other proteins involved in sporulation and spore biogenesis. Protein co-expression analysis revealed four co-expressed modules (termed blue, brown, green, and yellow). Modules brown and green are upregulated during sporulation and contain proteins associated with sporulation. Module blue is negatively correlated with modules brown and green, containing ribosomal and metabolic proteins. Finally, module yellow shows co-expression with the three other modules. Notably, several proteins not belonging to any of the known transcription regulons were identified as co-expressed with modules brown and green, and might also play roles during sporulation. Finally, levels of some coat proteins, for example morphogenetic coat proteins, decreased late in sporulation.


Assuntos
Bacillus subtilis/metabolismo , Bacillus subtilis/fisiologia , Proteoma/análise , Proteoma/metabolismo , Esporos Bacterianos/metabolismo , Esporos Bacterianos/fisiologia , Bacillus subtilis/citologia , Proteínas de Bactérias/classificação , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Esporos Bacterianos/citologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia
4.
Nat Commun ; 12(1): 5707, 2021 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-34588455

RESUMO

Bacillus subtilis can form structurally complex biofilms on solid or liquid surfaces, which requires expression of genes for matrix production. The transcription of these genes is activated by regulatory protein RemA, which binds to poorly conserved, repetitive DNA regions but lacks obvious DNA-binding motifs or domains. Here, we present the structure of the RemA homologue from Geobacillus thermodenitrificans, showing a unique octameric ring with the potential to form a 16-meric superstructure. These results, together with further biochemical and in vivo characterization of B. subtilis RemA, suggests that the protein can wrap DNA around its ring-like structure through a LytTR-related domain.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , DNA Bacteriano/metabolismo , Geobacillus/fisiologia , Fatores de Transcrição/metabolismo , Bacillus subtilis/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Cristalografia por Raios X , Regulação Bacteriana da Expressão Gênica , Modelos Genéticos , Mutagênese Sítio-Dirigida , Domínios e Motivos de Interação entre Proteínas/genética , Multimerização Proteica/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/genética , Fatores de Transcrição/isolamento & purificação , Fatores de Transcrição/ultraestrutura
5.
Sci Rep ; 11(1): 14473, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262108

RESUMO

Stripe rust (caused by Puccinia striiformis tritici) is one of the most devastating diseases of wheat. The most effective ways to control stripe rust are the use of resistant cultivars and the timely use of an appropriate dose of fungicide. However, the changing nature of rust pathogen outwits the use of resistant cultivars, and the use of a fungicide is associated with environmental problems. To control the disease without sacrificing the environment, we screened 16 endophytic bacteria, which were isolated from stripe rust-resistant wheat cultivars in our previous study, for their biocontrol potential. A total of 5 bacterial strains Serratia marcescens 3A, Bacillus megaterium 6A, Paneibacillus xylanexedens 7A, Bacillus subtilis 11A, and Staphyloccus agentis 15A showed significant inhibition of Puccinia striiformis f. sp. tritici (Pst) urediniospores germination. Two formulations i.e., fermented liquid with bacterial cell (FLBC) and fermented liquid without bacterial cells (FL) of each bacterial strain, were evaluated against the urediniospores germination. Formulations of five selected endophytic bacteria strains significantly inhibited the uredinioospores germination in the lab experiments. It was further confirmed on seedlings of Pakistani susceptible wheat cultivar Inqilab-91 in the greenhouse, as well as in semi-field conditions. FLBC and FL formulations applied 24 h before Pst inoculation (hbi) displayed a protective mode. The efficacy of FLBC was between 34.45 and 87.77%, while the efficacy of FL was between 39.27 and 85.16% when applied 24 hbi. The inoculated wheat cultivar Inqilab-91 was also tested under semi-field conditions during the 2017-2018 cropping season at the adult plant stage. The strains Bacillus megaterium 6A and Paneibacillus xylanexedens 7A alone significantly reduced the disease severity of stripe rust with the efficacy of 65.16% and 61.11% for the FLBC in protective effect, while 46.07% and 44.47% in curative effect, respectively. Inoculated seedlings of Inqilab-91 showed higher activities of antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL). The treated seedlings also showed higher expressions of pathogenesis-related (PR) protein genes, antifungal protein (PR-1), ß-1,3-endoglucanases (PR-2), endochitinases (PR-4), peroxidase (PR-9), and ribonuclease-like proteins (PR-10). These results indicated that endophytic bacteria have the biocontrol potential, which can be used to manage stripe rust disease. High production antioxidant enzymes, as well as high expression of PR protein genes, might be crucial in triggering the host defense mechanism against Pst.


Assuntos
Agentes de Controle Biológico , Endófitos/fisiologia , Doenças das Plantas/microbiologia , Puccinia/patogenicidade , Plântula/microbiologia , Triticum/microbiologia , Bacillus megaterium/fisiologia , Bacillus subtilis/fisiologia , Enzimas/metabolismo , Regulação da Expressão Gênica de Plantas , Microscopia Eletrônica de Varredura , Células Vegetais/microbiologia , Folhas de Planta/microbiologia , Proteínas de Plantas/metabolismo , Serratia marcescens/fisiologia , Staphylococcus/fisiologia , Triticum/fisiologia
6.
Food Funct ; 12(13): 5837-5849, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34018533

RESUMO

The present study was conducted to investigate the effects of dietary supplementation with Bacillus subtilis (BS) and xylo-oligosaccharides (XOS) on growth performance, intestinal morphology, intestinal microbial community, and metabolites of weaned piglets. One hundred and twenty-eight piglets were randomly allocated to one of four groups, including a control group (basal diet), BS group (basal diet + 500 g t-1 BS), XOS group (basal diet + 250 g t-1 XOS), and BS + XOS group (basal diet + 500 g t-1 BS + 250 g t-1 XOS). Dietary BS and XOS were mixed with the basal diet. All groups had eight replicates with four piglets per replicate. The experiment lasted for 42 days. The results showed that dietary XOS supplementation increased the ADFI and ADG, while decreasing the F/G. Dietary BS or XOS supplementation improved the intestinal morphology of weaned piglets by increasing the villus height and the ratio of villus height to crypt depth in the ileum. In addition, dietary XOS supplementation increased the concentrations of butyrate in the ileum and tryptamine and spermidine in the colon, while decreasing the concentration of indole in the colon compared with the control group. Dietary BS supplementation increased the colonic concentrations of butyrate, tryptamine, and cadaverine, while decreasing the concentration of skatole compared with the control group. The LEfSe analysis identified 16 biomarkers in the ileum of the BS group. The intestinal microbiota alterations of weaned piglets indicated that dietary BS or XOS supplementation could improve intestinal health by increasing the gut microbial diversity and altering the relative abundances of different bacterial species. Moreover, Spearman's correlation analysis revealed the potential link between gut microbiota alterations and metabolite changes of weaned piglets. These findings suggest that dietary XOS supplementation could alone improve the growth performance, while dietary BS or XOS and BS with XOS supplementation could influence intestinal health by altering the intestinal morphology, microbial community, and metabolites of weaned piglets. Meanwhile, there were interactions between BS and XOS in intestinal metabolites.


Assuntos
Bacillus subtilis/fisiologia , Suplementos Nutricionais , Microbioma Gastrointestinal/fisiologia , Oligossacarídeos/metabolismo , Ração Animal , Animais , Dieta , Duodeno/metabolismo , Íleo/metabolismo , Masculino , Suínos , Desmame
7.
Int J Food Microbiol ; 349: 109231, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34022614

RESUMO

Bacterial spores are important in food processing due to their ubiquity, resistance to high temperature and chemical inactivation. This work aims to study the effect of ultraviolet C (UVC) on the spores of Bacillus subtilis and Bacillus velezensis at a molecular and individual level to guide in deciding on the right parameters that must be applied during the processing of liquid foods. The spores were treated with UVC using phosphate buffer saline (PBS) as a suspension medium and their lethality rate was determined for each sample. Purified spore samples of B. velezensis and B. subtilis were treated under one pass in a UVC reactor to inactivate the spores. The resistance pattern of the spores to UVC treatment was determined using dipicolinic acid (Ca-DPA) band of spectral analysis obtained from Raman spectroscopy. Flow cytometry analysis was also done to determine the effect of the UVC treatment on the spore samples at the molecular level. Samples were processed for SEM and the percentage spore surface hydrophobicity was also determined using the Microbial Adhesion to Hydrocarbon (MATH) assay to predict the adhesion strength to a stainless-steel surface. The result shows the maximum lethality rate to be 6.5 for B. subtilis strain SRCM103689 (B47) and highest percentage hydrophobicity was 54.9% from the sample B. velezensis strain LPL-K103 (B44). The difference in surface hydrophobicity for all isolates was statistically significant (P < 0.05). Flow cytometry analysis of UVC treated spore suspensions clarifies them further into sub-populations unaccounted for by plate counting on growth media. The Raman spectroscopy identified B4002 as the isolate possessing the highest concentration of Ca-DPA. The study justifies the critical role of Ca-DPA in spore resistance and the possible sub-populations after UVC treatment that may affect product shelf-life and safety. UVC shows a promising application in the inactivation of resistant spores though there is a need to understand the effects at the molecular level to design the best parameters during processing.


Assuntos
Bacillus subtilis/efeitos da radiação , Bacillus/efeitos da radiação , Leite/microbiologia , Pasteurização/métodos , Esporos Bacterianos/efeitos da radiação , Animais , Bacillus/fisiologia , Bacillus/ultraestrutura , Bacillus subtilis/fisiologia , Bacillus subtilis/ultraestrutura , Aderência Bacteriana/efeitos da radiação , Interações Hidrofóbicas e Hidrofílicas/efeitos da radiação , Viabilidade Microbiana/efeitos da radiação , Esporos Bacterianos/fisiologia , Esporos Bacterianos/ultraestrutura , Raios Ultravioleta
8.
Microbiol Res ; 248: 126752, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33839506

RESUMO

Botrytis cinerea is a plant pathogen causing the gray mold disease in a plethora of host plants. The control of the disease is based mostly on chemical pesticides, which are responsible for environmental pollution, while they also pose risks for human health. Furthermore, B. cinerea resistant isolates have been identified against many fungicide groups, making the control of this disease challenging. The application of biocontrol agents can be a possible solution, but requires deep understanding of the molecular mechanisms in order to be effective. In this study, we investigated the multitrophic interactions between the biocontrol agent Bacillus subtilis MBI 600, a new commercialized biopesticide, the pathogen B. cinerea and their plant host. Our analysis showed that this biocontrol agent reduced B. cinerea mycelial growth in vitro, and was able to suppress the disease incidence on cucumber plants. Moreover, treatment with B. subtilis led to induction of genes involved in plant immunity. RNA-seq analysis of B. cinerea transcriptome upon exposure to bacterial secretome, showed that genes coding for MFS and ABC transporters were highly induced. Deletion of the Bcmfs1 MFS transporter gene, using a CRISP/Cas9 editing method, affected its virulence and the tolerance of B. cinerea to bacterial secondary metabolites. These findings suggest that specific detoxification transporters are involved in these interactions, with crucial role in different aspects of B. cinerea physiology.


Assuntos
Bacillus subtilis/fisiologia , Botrytis/efeitos dos fármacos , Proteção de Cultivos/métodos , Cucumis sativus/microbiologia , Doenças das Plantas/prevenção & controle , Agentes de Controle Biológico/farmacologia , Botrytis/crescimento & desenvolvimento , Botrytis/fisiologia , Cucumis sativus/genética , Cucumis sativus/imunologia , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Micélio/fisiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia
9.
Elife ; 102021 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-33835023

RESUMO

NusA and NusG are transcription factors that stimulate RNA polymerase pausing in Bacillus subtilis. While NusA was known to function as an intrinsic termination factor in B. subtilis, the role of NusG in this process was unknown. To examine the individual and combinatorial roles that NusA and NusG play in intrinsic termination, Term-seq was conducted in wild type, NusA depletion, ΔnusG, and NusA depletion ΔnusG strains. We determined that NusG functions as an intrinsic termination factor that works alone and cooperatively with NusA to facilitate termination at 88% of the 1400 identified intrinsic terminators. Our results indicate that NusG stimulates a sequence-specific pause that assists in the completion of suboptimal terminator hairpins with weak terminal A-U and G-U base pairs at the bottom of the stem. Loss of NusA and NusG leads to global misregulation of gene expression and loss of NusG results in flagella and swimming motility defects.


Assuntos
Bacillus subtilis/fisiologia , Proteínas de Bactérias/genética , Expressão Gênica , Terminação da Transcrição Genética , Fatores de Elongação da Transcrição/genética , Bacillus subtilis/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Fatores de Elongação da Transcrição/metabolismo
10.
mBio ; 12(2)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33849976

RESUMO

Division site selection is a vital process to ensure generation of viable offspring. In many rod-shaped bacteria, a dynamic protein system, termed the Min system, acts as a central regulator of division site placement. The Min system is best studied in Escherichia coli, where it shows a remarkable oscillation from pole to pole with a time-averaged density minimum at midcell. Several components of the Min system are conserved in the Gram-positive model organism Bacillus subtilis However, in B. subtilis, it is commonly believed that the system forms a stationary bipolar gradient from the cell poles to midcell. Here, we show that the Min system of B. subtilis localizes dynamically to active sites of division, often organized in clusters. We provide physical modeling using measured diffusion constants that describe the observed enrichment of the Min system at the septum. Mathematical modeling suggests that the observed localization pattern of Min proteins corresponds to a dynamic equilibrium state. Our data provide evidence for the importance of ongoing septation for the Min dynamics, consistent with a major role of the Min system in controlling active division sites but not cell pole areas.IMPORTANCE The molecular mechanisms that help to place the division septum in bacteria is of fundamental importance to ensure cell proliferation and maintenance of cell shape and size. The Min protein system, found in many rod-shaped bacteria, is thought to play a major role in division site selection. It was assumed that there are strong differences in the functioning and in the dynamics of the Min system in E. coli and B. subtilis Most previous attempts to address Min protein dynamics in B. subtilis have been hampered by the use of overexpression constructs. Here, functional fusions to Min proteins have been constructed by allelic exchange and state-of-the-art imaging techniques allowed to unravel an unexpected fast dynamic behavior of the B. subtilis Min system. Our data show that the molecular mechanisms leading to Min protein dynamics are not fundamentally different in E. coli and B. subtilis.


Assuntos
Bacillus subtilis/fisiologia , Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Proteínas de Ciclo Celular/genética , Modelos Teóricos
11.
Commun Biol ; 4(1): 468, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33850233

RESUMO

Microbes commonly display great genetic plasticity, which has allowed them to colonize all ecological niches on Earth. Bacillus subtilis is a soil-dwelling organism that can be isolated from a wide variety of environments. An interesting characteristic of this bacterium is its ability to form biofilms that display complex heterogeneity: individual, clonal cells develop diverse phenotypes in response to different environmental conditions within the biofilm. Here, we scrutinized the impact that the number and variety of the Rap-Phr family of regulators and cell-cell communication modules of B. subtilis has on genetic adaptation and evolution. We examine how the Rap family of phosphatase regulators impacts sporulation in diverse niches using a library of single and double rap-phr mutants in competition under 4 distinct growth conditions. Using specific DNA barcodes and whole-genome sequencing, population dynamics were followed, revealing the impact of individual Rap phosphatases and arising mutations on the adaptability of B. subtilis.


Assuntos
Adaptação Fisiológica/genética , Bacillus subtilis/fisiologia , Genes Bacterianos , Família Multigênica , Monoéster Fosfórico Hidrolases/metabolismo , Bacillus subtilis/enzimologia , Bacillus subtilis/genética , Regulação Bacteriana da Expressão Gênica , Percepção de Quorum
12.
Bull Math Biol ; 83(5): 60, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33856558

RESUMO

Biofilms are complex communities of bacteria that exhibit a variety of collective behaviors. These behaviors improve their ability to survive in many different environments. One of these collective behaviors seen in Bacillus subtilis is the ability for starving cells to stop the growth of other cells using potassium signaling and voltage changes. This signaling produces an oscillatory growth pattern so that during periods of low growth the nutrients diffuse deeper into the biofilm and reach the nutrient-starved, interior regions of the biomass. In this paper, we develop a mathematical model to describe this oscillatory behavior, and we use this model to develop a two-dimensional simulation that reproduces many of the important features seen in the experimental data. This simulation allows us to examine the spatial patterning of the oscillatory behavior to better understand the relationships between the various regions of the biofilm. Studying the spatial components of the metabolic and voltage oscillations could allow for the development of new control techniques for biofilms with complex shapes.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes , Modelos Biológicos , Potássio , Transdução de Sinais , Bacillus subtilis/fisiologia , Potássio/metabolismo
13.
J Bacteriol ; 203(14): e0011421, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-33927049

RESUMO

Biofilm dispersion is the final stage of biofilm development, during which biofilm cells actively escape from biofilms in response to deteriorating conditions within the biofilm. Biofilm dispersion allows cells to spread to new locations and form new biofilms in better locations. However, dispersal mechanisms have been elucidated only in a limited number of bacteria. Here, we investigated biofilm dispersion in Bacillus subtilis. Biofilm dispersion was clearly observed when B. subtilis was grown under static conditions in modified LB medium containing glycerol and manganese. Biofilm dispersion was synergistically caused by two mechanisms: decreased expression of the epsA operon encoding exopolysaccharide synthetases and the induction of sporulation. Indeed, constitutive expression of the epsA operon in the sporulation-defective ΔsigK mutant prevented biofilm dispersion. The addition of calcium to the medium prevented biofilm dispersion without significantly affecting the expression of the epsA operon and sporulation genes. In synthetic medium, eliminating calcium did not prevent the expression of biofilm matrix genes and, thereby, biofilm formation, but it attenuated biofilm architecture. These results indicate that calcium structurally stabilizes biofilms and causes resistance to biofilm dispersion mechanisms. Sporulation-dependent biofilm dispersion required the spoVF operon, encoding dipicolinic acid (DPA) synthase. During sporulation, an enormous amount of DPA is synthesized and stored in spores as a chelate with calcium. We speculate that, during sporulation, calcium bound to biofilm matrix components may be transported to spores as a calcium-DPA complex, which weakens biofilm structure and leads to biofilm dispersion. IMPORTANCE Bacteria growing as biofilms are notoriously difficult to eradicate and sometimes pose serious threats to public health. Bacteria escape from biofilms by degrading them when biofilm conditions deteriorate. This process, called biofilm dispersion, has been studied as a promising strategy for safely controlling biofilms. However, the regulation and mechanism of biofilm dispersion has been elucidated only in a limited number of bacteria. Here, we identified two biofilm dispersion mechanisms in the Gram-positive, spore-forming bacterium Bacillus subtilis. The addition of calcium to the medium stabilized biofilms and caused resistance to dispersal mechanisms. Our findings provide new insights into biofilm dispersion and biofilm control.


Assuntos
Bacillus subtilis/fisiologia , Biofilmes , Cálcio/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Óperon , Ácidos Picolínicos/metabolismo , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Bacterianos/metabolismo
14.
J Bacteriol ; 203(14): e0019221, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-33927051

RESUMO

The dispersal of bacterial cells from a matured biofilm can be mediated either by active or passive mechanisms. In this issue of the Journal of Bacteriology, Nishikawa and Kobayashi demonstrate that the presence of calcium influences the dispersal of spores from the pellicle biofilm of Bacillus subtilis (M. Nishikawa and K. Kobayashi, J Bacteriol 203:e00114-21, 2021, https://doi.org/10.1128/JB.00114-21). The authors propose that temporal heterogeneity in matrix production and chelation of calcium by dipicolinic acid in spores weakens the biofilm matrix and causes passive dispersal.


Assuntos
Bacillus subtilis/fisiologia , Biofilmes , Esporos Bacterianos/fisiologia , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Cálcio/metabolismo , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento
15.
Nat Rev Microbiol ; 19(9): 600-614, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33824496

RESUMO

Biofilm formation is a process in which microbial cells aggregate to form collectives that are embedded in a self-produced extracellular matrix. Bacillus subtilis is a Gram-positive bacterium that is used to dissect the mechanisms controlling matrix production and the subsequent transition from a motile planktonic cell state to a sessile biofilm state. The collective nature of life in a biofilm allows emergent properties to manifest, and B. subtilis biofilms are linked with novel industrial uses as well as probiotic and biocontrol processes. In this Review, we outline the molecular details of the biofilm matrix and the regulatory pathways and external factors that control its production. We explore the beneficial outcomes associated with biofilms. Finally, we highlight major advances in our understanding of concepts of microbial evolution and community behaviour that have resulted from studies of the innate heterogeneity of biofilms.


Assuntos
Bacillus subtilis/fisiologia , Biofilmes/crescimento & desenvolvimento , Interações Microbianas/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia
16.
J Bacteriol ; 203(12): e0003721, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-33782055

RESUMO

To cope with sudden changes in their environment, bacteria can use a bet-hedging strategy by dividing the population into cells with different properties. This so-called bimodal or bistable cellular differentiation is generally controlled by positive feedback regulation of transcriptional activators. Due to the continuous increase in cell volume, it is difficult for these activators to reach an activation threshold concentration when cells are growing exponentially. This is one reason why bimodal differentiation is primarily observed from the onset of the stationary phase, when exponential growth ceases. An exception is the bimodal induction of motility in Bacillus subtilis, which occurs early during exponential growth. Several mechanisms have been put forward to explain this, including double-negative feedback regulation and the stability of the mRNA molecules involved. In this study, we used fluorescence-assisted cell sorting (FACS) to compare the transcriptomes of motile and nonmotile cells and noted that expression of ribosomal genes is lower in motile cells. This was confirmed using an unstable green fluorescent protein (GFP) reporter fused to the strong ribosomal rpsD promoter. We propose that the reduction in ribosomal gene expression in motile cells is the result of a diversion of cellular resources to the synthesis of the chemotaxis and motility systems. In agreement with this, single-cell microscopic analysis showed that motile cells are slightly shorter than nonmotile cells, an indication of slower growth. We speculate that this growth rate reduction can contribute to the bimodal induction of motility during exponential growth. IMPORTANCE To cope with sudden environmental changes, bacteria can use a bet-hedging strategy and generate different types of cells within a population-so-called bimodal differentiation. For example, a Bacillus subtilis culture can contain both motile and nonmotile cells. In this study, we compared the gene expression between motile and nonmotile cells. It appeared that motile cells express fewer ribosomes. To confirm this, we constructed a ribosomal promoter fusion that enabled us to measure expression of this promoter in individual cells. This reporter fusion confirmed our initial finding. The reallocation of cellular resources from ribosome synthesis toward synthesis of the motility apparatus results in a reduction in growth. Interestingly, this growth reduction has been shown to stimulate bimodal differentiation.


Assuntos
Bacillus subtilis/fisiologia , Metabolismo Energético/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas de Fluorescência Verde , Movimento
17.
J Basic Microbiol ; 61(5): 396-405, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33682160

RESUMO

The growth discrepancy of Bacillus subtilis biofilms along different directions under the competitive growth drive the formation of anisotropic biofilm morphology directly. Two biofilms growing from two inoculating positions with different distances exhibit promoting or inhibiting growth behavior. Here we develop an optical imaging technology to observe the cell differentiation and the growth dynamics when the biofilm grows. It shows that the spatiotemporal distribution of different phenotypes affects the biofilm morphological evolution. We develop a program to calculate the velocity of cell motion within the biofilm, which is based on the feature point matching approach. We find the cell differentiation ununiformity in the neighboring region and its opposite region leads to the cell velocity difference in the competitive environment, the different cell motion further influences the biofilm morphology evolution. When biofilms grow with a long inoculating distance, there is always a gap between the them; when biofilms grow with a short inoculating distance, two biofilms gradually merge into a whole. Our work establishes a relationship between microscopic cells and macroscopic biofilm morphological which enables us to study the competitive growth process of biofilms from multiple perspectives.


Assuntos
Bacillus subtilis/genética , Bacillus subtilis/fisiologia , Biofilmes/crescimento & desenvolvimento , Imagem Óptica/métodos , Fenótipo , Proteínas de Bactérias/genética
18.
Microbiol Res ; 247: 126733, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33676313

RESUMO

Since sugarcane is a ratoon crop, genome analysis of plant growth-promoting bacteria that exist in its soil rhizosphere, can provide opportunity to better understand their characteristics and use of such bacteria in turn, may especially improve perennial crop productivity. In the present study, genome of two bacterial strains, one each of B. megaterium (BM89) and B. subtilis (BS87), isolated and reported earlier (Chandra et al., 2018), were sequenced and characterized. Though both strains have demonstrated plant growth promoting properties and enhanced in-vitro plant growth responses, functional annotation and analysis of genes indicated superiority of BS87 as it possessed more plant growth promotion attributable genes over BM89. Apart from some common genes, trehalose metabolism, glycine betaine production, peroxidases, super oxide dismutase, cold shock proteins and phenazine production associated genes were selectively identified in BS87 genome indicating better plant growth performances and survival potential under harsh environmental conditions. Genes for chitinase, d-cysteine desulfhydrase and γ-aminobutyric acid (GABA), as found in BM89, propose its selective utilization in defense and bio-control measures. Concomitant with better settlings' growth, scanning electron micrographs indicated these isolated and characterized bacteria exhibiting healthy colonization within root of sugarcane crop. Kegg pathways' assignment also revealed added pathways namely carbohydrate and amino acid metabolism attached to B. subtilis strain BS87, a preferable candidate for bio-fertilizer and its utilization to promote growth of both plant and ratoon crops of sugarcane usually experiencing harsh environmental conditions.


Assuntos
Bacillus megaterium/genética , Bacillus subtilis/genética , Desenvolvimento Vegetal , Rizosfera , Saccharum/crescimento & desenvolvimento , Saccharum/microbiologia , Sequenciamento Completo do Genoma , Bacillus megaterium/classificação , Bacillus megaterium/isolamento & purificação , Bacillus megaterium/fisiologia , Bacillus subtilis/classificação , Bacillus subtilis/isolamento & purificação , Bacillus subtilis/fisiologia , Proteínas e Peptídeos de Choque Frio , Produção Agrícola , Produtos Agrícolas/microbiologia , Fertilizantes , Genoma Bacteriano , Filogenia , Solo , Microbiologia do Solo
19.
J Bacteriol ; 203(10)2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33649146

RESUMO

Lytic enzymes play an essential role in the remodeling of bacterial peptidoglycan (PG), an extracellular mesh-like structure that retains the membrane in the context of high internal osmotic pressure. Peptidoglycan must be unfailingly stable to preserve cell integrity, but must also be dynamically remodeled for the cell to grow, divide, and insert macromolecular machines. The flagellum is one such macromolecular machine that transits the PG, and flagellar insertion is aided by localized activity of a dedicated PG lyase in Gram-negative bacteria. To date, there is no known dedicated lyase in Gram-positive bacteria for the insertion of flagella. Here, we take a reverse-genetic candidate-gene approach and find that cells mutated for the lytic transglycosylase CwlQ exhibit a severe defect in flagellum-dependent swarming motility. We further show that CwlQ is expressed by the motility sigma factor SigD and is secreted by the type III secretion system housed inside the flagellum. Nonetheless, cells with mutations of CwlQ remain proficient for flagellar biosynthesis even when mutated in combination with four other lyases related to motility (LytC, LytD, LytF, and CwlO). The PG lyase (or lyases) essential for flagellar synthesis in B. subtilis, if any, remains unknown.IMPORTANCE Bacteria are surrounded by a wall of peptidoglycan and early work in Bacillus subtilis was the first to suggest that bacteria needed to enzymatically remodel the wall to permit insertion of the flagellum. No PG remodeling enzyme alone or in combination, however, has been found to be essential for flagellar assembly in B. subtilis Here, we take a reverse-genetic candidate-gene approach and find that the PG lytic transglycosylase CwlQ is required for swarming motility. Subsequent characterization determined that while CwlQ was coexpressed with motility genes and is secreted by the flagellar secretion apparatus, it was not required for flagellar synthesis. The PG lyase needed for flagellar assembly in B. subtilis remains unknown.


Assuntos
Bacillus subtilis/enzimologia , Bacillus subtilis/fisiologia , Flagelos/metabolismo , Peptidoglicano Glicosiltransferase/metabolismo , Peptidoglicano/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/ultraestrutura , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Movimento , Mutação , Peptidoglicano Glicosiltransferase/genética , Fator sigma/metabolismo , Sistemas de Secreção Tipo III/metabolismo
20.
J Bacteriol ; 203(10)2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33649151

RESUMO

Integrative and conjugative elements (ICEs) are mobile genetic elements capable of transferring their own and other DNA. They contribute to the spread of antibiotic resistance and other important traits for bacterial evolution. Exclusion is a mechanism used by many conjugative plasmids and a few ICEs to prevent their host cell from acquiring a second copy of the cognate element. ICEBs1 of Bacillus subtilis has an exclusion mechanism whereby the exclusion protein YddJ in a potential recipient inhibits the activity of the ICEBs1-encoded conjugation machinery in a potential donor. The target of YddJ-mediated exclusion is the conjugation protein ConG (a VirB6 homolog). Here, we defined the regions of YddJ and ConG that confer exclusion specificity and determined the importance of exclusion to host cells. Using chimeras that had parts of ConG from ICEBs1 and the closely related ICEBat1, we identified a putative extracellular loop of ConG that conferred specificity for exclusion by the cognate YddJ. Using chimeras of YddJ from ICEBs1 and ICEBat1, we identified two regions in YddJ needed for exclusion specificity. We also found that YddJ-mediated exclusion reduced the death of donor cells following conjugation into recipients. Donor death was dependent on the ability of transconjugants to themselves become donors and was reduced under osmoprotective conditions, indicating that death was likely due to alterations in the donor cell envelope caused by excessive conjugation. We postulate that elements that can have high frequencies of transfer likely evolved exclusion mechanisms to protect the host cells from excessive death.IMPORTANCE Horizontal gene transfer is a driving force in bacterial evolution, responsible for the spread of many traits, including antibiotic and heavy metal resistance. Conjugation, one type of horizontal gene transfer, involves DNA transfer from donor to recipient cells through conjugation machinery and direct cell-cell contact. Exclusion mechanisms allow conjugative elements to prevent their host from acquiring additional copies of the element and are highly specific, enabling hosts to acquire heterologous elements. We defined regions of the exclusion protein and its target in the conjugation machinery that convey high specificity of exclusion. We found that exclusion protects donors from cell death during periods of high transfer. This is likely important for the element to enter new populations of cells.


Assuntos
Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Conjugação Genética , Sequências Repetitivas Dispersas , Bacillus subtilis/fisiologia , Proteínas de Bactérias/metabolismo , DNA Bacteriano/genética , Transferência Genética Horizontal , Viabilidade Microbiana , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...