Bacillus subtilis Kovács, Ákos T.
Trends in microbiology (Regular ed.),
August 2019, 2019-08-00, 20190801, Letnik:
27, Številka:
8
Journal Article
Recenzirano
Bacillus subtilis became the most studied species in the genus Bacillus due to its natural competence for uptake of extracellular DNA that facilitates simple genetic modification and occurrence of ...sporulation, one of the first studied bacterial cell differentiation processes. The dormant spores can survive harsh circumstances (high temperature, desiccation, UV, and γ-radiation), predation by microorganisms and macroorganisms, or even extraterrestrial conditions. B. subtilis can be isolated from various environments, from soil to marine habitats, and utilized in various applications from enzyme production and food fermentation to plant biocontrol. B. subtilis is a model microorganism for studying cell division, protein secretion, surface motility (swimming, swarming, and sliding), biofilm development, attachment to plant root or fungal hyphae, secondary metabolite production, cytoplasm exchange via intercellular nanotubes, extracellular vesicle release, and kin-discrimination.
A biofilm is a common life form where bacterial cells crowd together surrounded by an extracellular matrix (ECM). Traditionally, the ECM is considered as a structural material that glues and shields ...the biofilm cells. Here we describe alternative functions of the ECM, highlighting how it benefits microbes beyond the biofilms. Next to protecting free-living cells, the ECM participates in signaling, migration, and genetic exchange either being freely shared with other species or being exclusive to siblings. Considering the structural and recently discovered functions of the ECM, we also attempt to revise its role in sociomicrobiology. In the light of recent findings, the canonical view on ECM as a passive structural material of biofilms should be revisited.
Summary
Bacteria are able to translocate over surfaces using different types of active and passive motility mechanisms. Sliding is one of the passive types of movement since it is powered by the ...pushing force of dividing cells and additional factors facilitating the expansion over surfaces. In this review, we describe the sliding proficient bacteria that were previously investigated in details highlighting the sliding facilitating compounds and the regulation of sliding motility. Besides surfactants that reduce the friction between cells and substratum, other compounds including exopolysaccharides, hydrophobic proteins, or glycopeptidolipids where discovered to promote sliding. Therefore, we present the sliding bacteria in three groups depending on the additional compound required for sliding. Despite recent accomplishments in sliding research there are still many open questions about the mechanisms underlying sliding motility and its regulation in diverse bacterial species.
Plant–microbiome functioning depends on intricate signaling pathways including plant-derived excretions that induce microbial gene expression. Marc Ongena and his team (Boubsi et al.) dissect how the ...pectin backbone homogalacturonan promotes bacterial differentiation programs of Bacillus velezensis, potentially facilitating its establishment in the rhizosphere.
Plant–microbiome functioning depends on intricate signaling pathways including plant-derived excretions that induce microbial gene expression. Marc Ongena and his team (Boubsi et al.) dissect how the pectin backbone homogalacturonan promotes bacterial differentiation programs of Bacillus velezensis, potentially facilitating its establishment in the rhizosphere.
Abstract Experimental evolution in a laboratory helps researchers to understand the genetic and phenotypic background of adaptation under a particular condition. Simultaneously, the simplified ...environment that represents certain aspects of a complex natural niche permits the dissection of relevant parameters behind the selection, including temperature, oxygen availability, nutrients, and biotic factors. The presence of other microorganisms or a host has a major influence on microbial evolution that often differs from the adaptation paths observed in response to abiotic conditions. In the current issue of the ISME Journal, Cosetta and colleagues reveal how cross-kingdom interaction representing the cheese microbiome succession promotes distinct evolution of the food- and animal-associated bacterium, Staphylococcus xylosus. The authors also identified a global regulator-dependent adaption that leads to evolved derivatives exhibiting reduced pigment production and colony morphologies in addition to altered differentiation phenotypes that potentially contribute to increased fitness.
For several decades, laboratory evolution has served as a powerful method to manipulate microorganisms and to explore long-term dynamics in microbial populations. Next to canonical Escherichia coli ...planktonic cultures, experimental evolution has expanded into alternative cultivation methods and species, opening the doors to new research questions. Bacillus subtilis, the spore-forming and root-colonizing bacterium, can easily develop in the laboratory as a liquid–air interface colonizing pellicle biofilm. Here, we summarize recent findings derived from this tractable experimental model. Clonal pellicle biofilms of B. subtilis can rapidly undergo morphological and genetic diversification creating new ecological interactions, for example, exploitation by biofilm non-producers. Moreover, long-term exposure to such matrix non-producers can modulate cooperation in biofilms, leading to different phenotypic heterogeneity pattern of matrix production with larger subpopulation of “ON” cells. Alternatively, complementary variants of biofilm non-producers, each lacking a distinct matrix component, can engage in a genetic division of labor, resulting in superior biofilm productivity compared to the “generalist” wild type. Nevertheless, inter-genetic cooperation appears to be evanescent and rapidly vanquished by individual biofilm formation strategies altering the amount or the properties of the remaining matrix component. Finally, fast-evolving mobile genetic elements can unpredictably shift intra-species interactions in B. subtilis biofilms. Understanding evolution in clonal biofilm populations will facilitate future studies in complex multispecies biofilms that are more representative of nature.
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•B. subtilis pellicle serves as a tractable and realistic model in laboratory evolution.•Biofilm diversification creates new competitive or cooperative interactions.•Division of labor in biofilms is vulnerable to evolution of individual traits.•Evolution with non-producers alters phenotypic heterogeneity of matrix expression.•Understanding complexity evolution in clonal population aids multispecies systems.
Outcomes of pairwise interactions between bacilli and pseudomonads do not correlate with species-level taxonomy.Most interaction pairs of Bacillus and Pseudomonas engage in net negative interactions ...that stabilize into coexistence.Strains from both genera are ubiquitous and often coisolated from soil. Understanding why this is the case may translate to other microbial interactions and deepen our insight into microbial ecology in general.
Bacillus and Pseudomonas ubiquitously occur in natural environments and are two of the most intensively studied bacterial genera in the soil. They are often coisolated from environmental samples, and as a result, several studies have experimentally cocultured bacilli and pseudomonads to obtain emergent properties. Even so, the general interaction between members of these genera is virtually unknown. In the past decade, data on interspecies interactions between natural isolates of Bacillus and Pseudomonas has become more detailed, and now, molecular studies permit mapping of the mechanisms behind their pairwise ecology. This review addresses the current knowledge about microbe–microbe interactions between strains of Bacillus and Pseudomonas and discusses how we can attempt to generalize the interaction on a taxonomic and molecular level.
Abstract Many bacteria grow on surfaces in nature, where they form cell collectives that compete for space. Within these collectives, cells often secrete molecules that benefit surface spreading by, ...for example, reducing surface tension or promoting filamentous growth. Although we have a detailed understanding of how these molecules are produced, much remains unknown about their role in surface competition. Here we examine sliding motility in Bacillus subtilis and compare how secreted molecules, essential for sliding, affect intraspecific cooperation and competition on a surface. We specifically examine (i) the lipopeptide surfactin, (ii) the hydrophobin protein BslA, and (iii) exopolysaccharides (EPS). We find that these molecules have a distinct effect on surface competition. Whereas surfactin acts like a common good, which is costly to produce and benefits cells throughout the surface, BslA and EPS are cost-free and act locally. Accordingly, surfactin deficient mutants can exploit the wild-type strain in competition for space, while BslA and EPS mutants cannot. Supported by a mathematical model, we show that three factors are important in predicting the outcome of surface competition: the costs of molecule synthesis, the private benefits of molecule production, and the diffusion rate. Our results underscore the intricate extracellular biology that can drive bacterial surface competition.
Members of the Bacillus genus are widely distributed throughout natural environments and have been studied for decades among others for their physiology, genetics, ecological functions, and ...applications. However, despite its prevalence in nature, the characterization and classification of Bacillus remain challenging due to its complex and ever‐evolving taxonomic framework. This review addresses the current state of the Bacillus taxonomic landscape and summarizes the critical points in the development of Bacillus phylogeny. With a clear view of Bacillus phylogeny as a foundation, we subsequently review the methodologies applied in identifying and quantifying Bacillus, while also discussing their respective advantages and disadvantages.
The review by Xu and Kovács highlights the taxonomy and quantification of Bacillus diversity that allows dissection of distribution and abundance in the environment towards the study of Bacillus ecology.
A fungal scent from the cheese Kovács, Ákos T.
Environmental microbiology,
November 2020, 2020-11-00, 20201101, Letnik:
22, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Summary
Assembly of microbial communities is shaped by various physical and chemical factors deriving from their environment, including other microbes inhabiting the certain niche. In addition to ...direct cell–cell contacts, primary and secondary metabolites impact the growth of microbial community members. Metabolites might act as growth‐promoting (e.g., cross‐feeding), growth‐inhibiting (e.g., antimicrobials) or signalling molecules. In multi‐species microbial assemblies, secreted metabolites might influence specific members of the community, altering species abundances and therefore the functioning of these microcosms. In the current issue, Cosetta and colleagues describe a unique volatile metabolite‐mediated cross‐kingdom interaction that shapes the cheese rind community assembly. The study paves the way of our understanding how fungus‐produced volatile compounds promote the growth of a certain bacterial genus, a principal connection between community members of the cheese rind.
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