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Victor Sourjik - One of the best experts on this subject based on the ideXlab platform.

  • running after your host stimulation of Bacterial Motility promotes colonization
    Cell Host & Microbe, 2021
    Co-Authors: Remy Colin, Victor Sourjik
    Abstract:

    In this issue of Cell Host and Microbe, Robinson et al. (2021) make elegant use of experimental evolution to demonstrate that increased Motility promotes migration toward and colonization of zebrafish larvae by a commensal bacterium. Stimulation of Motility depends on Bacterial second messenger and on signals released by resident host microbiota.

  • inefficient secretion of anti sigma factor flgm inhibits Bacterial Motility at high temperature
    iScience, 2019
    Co-Authors: Iaroslav Rudenko, Timo Glatter, Victor Sourjik
    Abstract:

    Summary Temperature is one of the key cues that enable microorganisms to adjust their physiology in response to environmental changes. Here we show that Motility is the major cellular function of Escherichia coli that is differentially regulated between growth at normal host temperature of 37°C and the febrile temperature of 42°C. Expression of both class II and class III flagellar genes is reduced at 42°C because of lowered level of the upstream activator FlhD. Class III genes are additionally repressed because of the destabilization and malfunction of secretion apparatus at high temperature, which prevents secretion of the anti-sigma factor FlgM. This mechanism of repression apparently accelerates loss of Motility at 42°C. We hypothesize that E. coli perceives high temperature as a sign of inflammation, downregulating flagella to escape detection by the immune system of the host. Secretion-dependent coupling of gene expression to the environmental temperature is likely common among many bacteria.

  • inefficient secretion of anti sigma factor flgm inhibits Bacterial Motility at high temperature
    Social Science Research Network, 2019
    Co-Authors: Iaroslav Rudenko, Timo Glatter, Victor Sourjik
    Abstract:

    Temperature is one of the key cues that enable microorganisms to adjust their physiology in response to environmental changes. Here we show that Motility is the major cellular function of Escherichia coli that is differentially regulated between growth at normal host temperature of 37°C and the febrile temperature of 42°C. We demonstrate that this downregulation primarily occurs due to the malfunction of secretion apparatus, apparently related to the disassembly of the flagellar basal body. This prevented secretion of the anti-sigma factor FlgM and resulted in FlgM-dependent repression of class III Motility genes at 42°C, while enabling prompt reactivation of Motility upon decrease of temperature. We hypothesize that E. coli perceives high temperature as a sign of inflammation, downregulating flagella to escape detection by immune system of the host. Secretion-dependent coupling of gene expression to the environmental temperature represents a novel mode of stress response, which is likely to be common among many Bacterial species.

  • evolutionary remodeling of Bacterial Motility checkpoint control
    Cell Reports, 2017
    Co-Authors: Bhaswar Ghosh, Ferencz S Paldy, Remy Colin, Thomas Heimerl, Victor Sourjik
    Abstract:

    Summary Regulatory networks play a central role in the relationship between genotype and phenotype in all organisms. However, the mechanisms that underpin the evolutionary plasticity of these networks remain poorly understood. Here, we used experimental selection for enhanced Bacterial Motility in a porous environment to explore the adaptability of one of the most complex networks known in bacteria. We found that the resulting phenotypic changes are mediated by adaptive mutations in several functionally different proteins, including multiple components of the flagellar motor. Nevertheless, this evolutionary adaptation could be explained by a single mechanism, namely remodeling of the checkpoint regulating flagellar gene expression. Supported by computer simulations, our findings suggest that the specific "bow-tie" topology of the checkpoint facilitates evolutionary tuning of the cost-benefit trade-off between Motility and growth. We propose that bow-tie regulatory motifs, which are widespread in cellular networks, play a general role in evolutionary adaptation.

Benjamin J Buckley - One of the best experts on this subject based on the ideXlab platform.

  • novel amiloride derivatives that inhibit Bacterial Motility across multiple strains and stator types
    Journal of Bacteriology, 2021
    Co-Authors: M I Islam, Yoshiyuki Sowa, J H Bae, Tsubasa Ishida, Pietro Ridone, J Lin, Michael J Kelso, Benjamin J Buckley
    Abstract:

    The Bacterial flagellar motor (BFM) is a protein complex that confers Motility to cells and contributes to survival and virulence. The BFM consists of stators that are ion-selective membrane protein complexes and a rotor that directly connects to a large filament, acting as a propeller. The stator complexes couple ion transit across the membrane to torque that drives rotation of the motor. The most common ion gradients that drive BFM rotation are protons (H+) and sodium ions (Na+). The sodium-powered stators, like those in the PomA/PomB stator complex of Vibrio spp., can be inhibited by sodium channel inhibitors, in particular, by phenamil, a potent and widely used inhibitor. However, relatively few new sodium Motility inhibitors have been described since the discovery of phenamil. In this study, we characterized two possible Motility inhibitors, HM2-16F and BB2-50F, from a small library of previously reported amiloride derivatives. We used three approaches: effect on rotation of tethered cells, effect on free-swimming bacteria, and effect on rotation of marker beads. We showed that both HM2-16F and BB2-50F stopped rotation of tethered cells driven by Na+ motors comparable to phenamil at matching concentrations and could also stop rotation of tethered cells driven by H+ motors. Bead measurements in the presence and absence of stators confirmed that the compounds did not inhibit rotation via direct association with the stator, in contrast to the established mode of action of phenamil. Overall, HM2-16F and BB2-50F stopped swimming in both Na+ and H+ stator types and in pathogenic and nonpathogenic strains. IMPORTANCE Here, we characterized two novel amiloride derivatives in the search for antimicrobial compounds that target Bacterial Motility. These compounds were shown to inhibit flagellar Motility at 10 μM across multiple strains: from nonpathogenic Escherichia coli with flagellar rotation driven by proton or chimeric sodium-powered stators, to proton-powered pathogenic E. coli (enterohemorrhagic E. coli or uropathogenic E. coli [EHEC or UPEC, respectively]), and finally, sodium-powered Vibrio alginolyticus. Broad antiMotility compounds such as these are important tools in our efforts to control virulence of pathogens in health and agricultural settings.

  • novel amiloride derivatives that inhibit Bacterial Motility across multiple strains and stator types
    bioRxiv, 2021
    Co-Authors: M I Islam, Yoshiyuki Sowa, J H Bae, Tsubasa Ishida, Pietro Ridone, J Lin, Michael J Kelso, Benjamin J Buckley
    Abstract:

    Abstract The Bacterial flagellar motor (BFM) is a protein complex that confers Motility to cells and contributes to survival and virulence. The BFM consists of stators that are ion-selective membrane protein complexes and a rotor that directly connects to a large filament, acting as a propeller. The stator complexes couple ion transit across the membrane to torque that drives rotation of the motor. The most common ion gradients that drive BFM rotation are protons (H+) and sodium ions (Na+). The sodium-powered stators, like those in the PomAPomB stator complex of Vibrio spp, can be inhibited by sodium channel inhibitors, in particular, by phenamil, a potent and widely used inhibitor. However, relatively few new sodium-Motility inhibitors have been described since the discovery of phenamil. In this study, we discovered two Motility inhibitors HM2-16F and BB2-50F from a small library of previously reported amiloride derivatives. Using a tethered cell assay, we showed that both HM2-16F and BB2-50F had inhibition comparable to that of phenamil on Na+ driven motors at matching concentrations, with an additional ability to inhibit rotation in H+ driven motors. The two compounds did not exhibit adverse effects on Bacterial growth at the Motility-inhibiting concentration of 10 μM, however toxicity was seen for BB2-50F at 100 μM. We performed higher resolution measurements to examine rotation inhibition at moderate (1 μm polystyrene bead) and low loads (60 nm gold bead) and in both the presence and absence of stators. These measurements suggested that the compounds did not inhibit rotation via direct association with the stator, in contrast to the established mode of action of phenamil. Overall, HM2-16F and BB2-50F showed reversible inhibition of Motility across a range of loads, in both Na+ and H+ stator types, and in pathogenic and non-pathogenic strains. Importance Here we characterised two novel amiloride derivatives in the search for antimicrobial compounds that target Bacterial virulence. Our two compounds were shown to inhibit flagellar Motility at 10 μM across multiple strains, from non-pathogenic E. coli with flagellar rotation driven by proton or chimeric sodium powered stators, to proton-powered pathogenic E. coli (EHEC/UPEC) and lastly in sodium-powered Vibrio alginolyticus. Broad anti-Motility compounds such as these are important tools in our efforts control virulence of pathogens in health and agricultural settings, as well as providing new compounds to study the inhibited rotation of the flagellar motor.

Chaomin Sun - One of the best experts on this subject based on the ideXlab platform.

  • the cyclic lipopeptides suppress the Motility of vibrio alginolyticus via targeting the na driven flagellar motor component motx
    Environmental Microbiology, 2020
    Co-Authors: Rui Liu, Rikuan Zheng, Ge Liu, Chaomin Sun
    Abstract:

    In our previous study, we found that pumilacidin-like cyclic lipopeptides (CLPs) derived from marine bacterium Bacillus sp. strain 176 significantly suppressed the mobile capability and virulence of Vibrio alginolyticus. Here, to further disclose the mechanism of CLPs inhibiting the Motility of V. alginolyticus, we first applied transcriptomic analysis to V. alginolyticus treated with or without CLPs. The transcriptomic results showed that the expression of several important components of the Na+ -driven flagellar motor closely related to Bacterial Motility were markedly suppressed, suggesting that the structure and function of Na+ -driven flagellar motor might be disabled by CLPs. The transcriptomic data were further analysed by the protein-protein interaction network, and the results supported that MotX, one of the essential components of Na+ -driven flagellar motor was most likely the action target of CLPs. In combination of gene knockout, electrophoretic mobility shift assay and immunoblotting techniques, CLPs were demonstrated to affect the rotation of flagella of Vibrio alginolyticus via direct interacting with the Na+ -driven flagellar motor component MotX, which eventually inhibited the Bacterial Motility. Interestingly, homologues of MotX were found broadly distributed and highly conserved in different pathogenic species, which extends the application range of CLPs as an antiBacterial drug targeting Bacterial Motility in many pathogens.

  • pumilacidin like lipopeptides derived from marine bacterium bacillus sp strain 176 suppress the Motility of vibrio alginolyticus
    Applied and Environmental Microbiology, 2017
    Co-Authors: Pengyuan Xiu, Rui Liu, Dechao Zhang, Chaomin Sun
    Abstract:

    Bacterial Motility is a crucial factor during the invasion and colonization processes of pathogens, which makes it an attractive therapeutic drug target. Here, we isolated a marine bacterium (Vibrio alginolyticus strain 178) from a seamount in the tropical West Pacific that exhibits vigorous Motility on agar plates and severe pathogenicity to zebrafish. We found that V. alginolyticus 178 Motility was significantly suppressed by another marine bacterium, Bacillus sp. strain 176, isolated from the same niche. We isolated, purified, and characterized two different cyclic lipopeptides (CLPs) from Bacillus sp. 176 using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The two related CLPs have a pumilacidin-like structure and were both effective inhibitors of V. alginolyticus 178 Motility. The CLPs differ by only one methylene group in their fatty acid chains. In addition to Motility suppression, the CLPs also induced cell aggregation in the medium and reduced adherence of V. alginolyticus 178 to glass substrates. Notably, upon CLP treatment, the expression levels of two V. alginolyticus flagellar assembly genes (flgA and flgP) dropped dramatically. Moreover, the CLPs inhibited biofilm formation in several other strains of pathogenic bacteria without inducing cell death. This study indicates that CLPs from Bacillus sp. 176 show promise as antimicrobial lead compounds targeting Bacterial Motility and biofilm formation with a low potential for eliciting antibiotic resistance.IMPORTANCE Pathogenic bacteria often require Motility to establish infections and subsequently spread within host organisms. Thus, Motility is an attractive therapeutic target for the development of novel antibiotics. We found that cyclic lipopeptides (CLPs) produced by marine bacterium Bacillus sp. strain 176 dramatically suppress the Motility of the pathogenic bacterium Vibrio alginolyticus strain 178, reduce biofilm formation, and promote cellular aggregation without inducing cell death. These findings suggest that CLPs hold great promise as potential drug candidates targeting Bacterial Motility and biofilm formation with a low overall potential for triggering antibiotic resistance.

Masayoshi Nishiyama - One of the best experts on this subject based on the ideXlab platform.

  • Bacterial Motility Measured by a Miniature Chamber for High-Pressure Microscopy
    Biophysical Journal, 2015
    Co-Authors: Masayoshi Nishiyama, Seiji Kojima
    Abstract:

    Hydrostatic pressure is one of the physical stimuli that characterize the environment of living matter. Many microorganisms thrive under high pressure and may even physically or geochemically require this extreme environmental condition. In contrast, application of pressure is detrimental to most life on Earth; especially to living organisms under ambient pressure conditions. To study the mechanism of how living things adapt to high-pressure conditions, it is necessary to monitor directly the organism of interest under various pressure conditions. Here, we report a miniature chamber for high-pressure microscopy [1]. The chamber was equipped with a built-in separator, in which water pressure was properly transduced to that of the sample solution. The apparatus developed could apply pressure up to 150 MPa, and enabled us to acquire bright-field and epifluorescence images at various pressures and temperatures. We demonstrated that the application of pressure acted directly and reversibly on the swimming Motility of Escherichia coli cells. The present technique should be applicable to a wide range of dynamic biological processes that depend on applied pressures [2, 3].[1] Nishiyama M. and S. Kojima. 2012. Bacterial Motility Measured by a Miniature Chamber for High-Pressure Microscopy. Int. J. Mol. Sci.13: 9225-9239.[2] Nishiyama M. et al. 2013. High Hydrostatic Pressure Induces Counterclockwise to Clockwise Reversals of the Escherichia coli Flagellar Motor. J. Bactetiol.195: 1809-1814.[3] Okuno D. et al., 2013. Single-Molecule Analysis of the Rotation of F1-ATPase under High Hydrostatic Pressure. Biophys. J.105:1635-1642.

  • Bacterial Motility measured by a miniature chamber for high-pressure microscopy.
    International journal of molecular sciences, 2012
    Co-Authors: Masayoshi Nishiyama, Seiji Kojima
    Abstract:

    Hydrostatic pressure is one of the physical stimuli that characterize the environment of living matter. Many microorganisms thrive under high pressure and may even physically or geochemically require this extreme environmental condition. In contrast, application of pressure is detrimental to most life on Earth; especially to living organisms under ambient pressure conditions. To study the mechanism of how living things adapt to high-pressure conditions, it is necessary to monitor directly the organism of interest under various pressure conditions. Here, we report a miniature chamber for high-pressure microscopy. The chamber was equipped with a built-in separator, in which water pressure was properly transduced to that of the sample solution. The apparatus developed could apply pressure up to 150 MPa, and enabled us to acquire bright-field and epifluorescence images at various pressures and temperatures. We demonstrated that the application of pressure acted directly and reversibly on the swimming Motility of Escherichia coli cells. The present technique should be applicable to a wide range of dynamic biological processes that depend on applied pressures.

  • microscopic analysis of Bacterial Motility at high pressure
    Biophysical Journal, 2012
    Co-Authors: Masayoshi Nishiyama, Yoshiyuki Sowa
    Abstract:

    The Bacterial flagellar motor is a molecular machine that converts an ion flux to the rotation of a helical flagellar filament. Counterclockwise rotation of the filaments allows them to join in a bundle and propel the cell forward. Loss of Motility can be caused by environmental factors such as temperature, pH, and solvation. Hydrostatic pressure is also a physical inhibitor of Bacterial Motility, but the detailed mechanism of this inhibition is still unknown. Here, we developed a high-pressure microscope that enables us to acquire high-resolution microscopic images, regardless of applied pressures. We also characterized the pressure dependence of the Motility of swimming Escherichia coli cells and the rotation of single flagellar motors. The fraction and speed of swimming cells decreased with increased pressure. At 80 MPa, all cells stopped swimming and simply diffused in solution. After the release of pressure, most cells immediately recovered their initial Motility. Direct observation of the Motility of single flagellar motors revealed that at 80 MPa, the motors generate torque that should be sufficient to join rotating filaments in a bundle. The discrepancy in the behavior of free swimming cells and individual motors could be due to the applied pressure inhibiting the formation of rotating filament bundles that can propel the cell body in an aqueous environment.

Andrew Camilli - One of the best experts on this subject based on the ideXlab platform.

  • immunity provided by an outer membrane vesicle cholera vaccine is due to o antigen specific antibodies inhibiting Bacterial Motility
    Infection and Immunity, 2017
    Co-Authors: Zhu Wang, David W Lazinski, Andrew Camilli
    Abstract:

    ABSTRACT An outer membrane vesicle (OMV)-based cholera vaccine is highly efficacious in preventing intestinal colonization in the suckling mouse model. Immunity from OMVs comes from immunoglobulin (Ig), particularly IgG, in the milk of mucosally immunized dams. Anti-OMV IgG renders Vibrio cholerae organisms immotile, thus they pass through the small intestine without colonizing. However, the importance of Motility inhibition for protection and the mechanism by which Motility is inhibited remain unclear. By using both in vitro and in vivo experiments, we found that IgG inhibits Motility by specifically binding to the O-antigen of V. cholerae. We demonstrate that the bivalent structure of IgG, although not required for binding to the O-antigen, is required for Motility inhibition. Finally, we show using competition assays in suckling mice that inhibition of Motility appears to be responsible for most, if not all, of the protection engendered by OMV vaccination, thus providing insight into the mechanism of immune protection.

  • mucosal immunization with vibrio cholerae outer membrane vesicles provides maternal protection mediated by antilipopolysaccharide antibodies that inhibit Bacterial Motility
    Infection and Immunity, 2010
    Co-Authors: Anne L Bishop, Stefan Schild, Bharathi Patimalla, Brian A Klein, Andrew Camilli
    Abstract:

    Vibrio cholerae is the causative agent of cholera, a severe diarrheal disease that remains endemic in many parts of the world and can cause outbreaks wherever sanitation and clean water systems break down. Prevention of disease could be achieved through improved sanitation and clean water provision supported by vaccination. V. cholerae serogroup O1 is the major cause of cholera; O1 serotypes Inaba and Ogawa have similar disease burdens, while O139 is the only non-O1 serogroup to cause epidemics. We showed previously that immunization of adult female mice with purified V. cholerae outer membrane vesicles (OMVs) elicits an antibody response that protect neonates from oral V. cholerae challenge and that suckling from an immunized dam accounts for the majority of protection from V. cholerae colonization. Here we report that lipopolysaccharide (LPS) is the major OMV protective antigen. Mucosal immunization with OMVs from Inaba or Ogawa provides significant cross-serotype protection from V. cholerae colonization, although serotype-specific antigens are dominant. OMVs from O1 or O139 do not provide cross-serogroup protection, but by immunization with a mixture of O1 and O139 OMVs, cross-serogroup protection was achieved. Neonatal protection is not associated with significant Bacterial death but may involve inhibition of Motility, as antibodies from OMV-immunized mice inhibit V. cholerae Motility in vitro, with trends that parallel in vivo protection. Motility assays also reveal that a higher antibody titer is required to immobilize O139 compared to O1, a phenotype that is O139 capsule dependent.