scholarly journals High-throughput PCR Screening of Genes for Three-component Regulatory System Putatively Involved in Quorum Sensing from Low-G+C Gram-positive Bacteria

2003 ◽  
Vol 67 (3) ◽  
pp. 480-489 ◽  
Author(s):  
Jiro NAKAYAMA ◽  
Antoon D. L. AKKERMANS ◽  
Willem M. DE VOS
Keyword(s):  
Quorum Sensing ◽  
High Throughput ◽  
Regulatory System ◽  
Gram Positive ◽  
Pcr Screening ◽  
Gram Positive Bacteria

scholarly journals Ambuic Acid Inhibits the Biosynthesis of Cyclic Peptide Quormones in Gram-Positive Bacteria

2008 ◽  
Vol 53 (2) ◽  
pp. 580-586 ◽  
Author(s):  
Jiro Nakayama ◽  
Yumi Uemura ◽  
Kenzo Nishiguchi ◽  
Norito Yoshimura ◽  
Yasuhiro Igarashi ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Regulatory System ◽  
Gram Positive ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Secondary Fungal Metabolite ◽  
Potential Use

ABSTRACT Quorum sensing is a cell-density-dependent regulatory system in gram-positive bacteria and is often regulated by cyclic peptides called “quormones,” which function as extracellular communication signals. With an aim to discover an antipathogenic agent targeting quorum sensing in gram-positive bacteria, we screened 153 samples of fungal butanol extracts with the guidance of the inhibition of quorum-sensing-mediated gelatinase production in Enterococcus faecalis. Following the screenings, we found that ambuic acid, a known secondary fungal metabolite, inhibited the quorum-sensing-mediated gelatinase production without influencing the growth of E. faecalis. We further demonstrated that ambuic acid targeted the biosynthesis of a cyclic peptide quormone called gelatinase biosynthesis-activating pheromone. Furthermore, ambuic acid also inhibited the biosynthesis of the cyclic peptide quormones of Staphylococcus aureus and Listeria innocua. These results suggest the potential use of ambuic acid as a lead compound of antipathogenic drugs that target the quorum-sensing-mediated virulence expression of gram-positive bacteria.

scholarly journals A Two-Component Regulatory System Impacts Extracellular Membrane-Derived Vesicle Production in Group A Streptococcus

mBio ◽  
2016 ◽  
Vol 7 (6) ◽  
Author(s):  
Ulrike Resch ◽  
James Anthony Tsatsaronis ◽  
Anaïs Le Rhun ◽  
Gerald Stübiger ◽  
Manfred Rohde ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Secretory Pathway ◽  
Group A Streptococcus ◽  
Regulatory System ◽  
Surface Proteins ◽  
Streptococcal Toxic Shock Syndrome ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Two Component ◽  
Group A

ABSTRACT Export of macromolecules via extracellular membrane-derived vesicles (MVs) plays an important role in the biology of Gram-negative bacteria. Gram-positive bacteria have also recently been reported to produce MVs; however, the composition and mechanisms governing vesiculogenesis in Gram-positive bacteria remain undefined. Here, we describe MV production in the Gram-positive human pathogen group A streptococcus (GAS), the etiological agent of necrotizing fasciitis and streptococcal toxic shock syndrome. M1 serotype GAS isolates in culture exhibit MV structures both on the cell wall surface and in the near vicinity of bacterial cells. A comprehensive analysis of MV proteins identified both virulence-associated protein substrates of the general secretory pathway in addition to “anchorless surface proteins.” Characteristic differences in the contents, distributions, and fatty acid compositions of specific lipids between MVs and GAS cell membrane were also observed. Furthermore, deep RNA sequencing of vesicular RNAs revealed that GAS MVs contained differentially abundant RNA species relative to bacterial cellular RNA. MV production by GAS strains varied in a manner dependent on an intact two-component system, CovRS, with MV production negatively regulated by the system. Modulation of MV production through CovRS was found to be independent of both GAS cysteine protease SpeB and capsule biosynthesis. Our data provide an explanation for GAS secretion of macromolecules, including RNAs, lipids, and proteins, and illustrate a regulatory mechanism coordinating this secretory response. IMPORTANCE Group A streptococcus (GAS) is a Gram-positive bacterial pathogen responsible for more than 500,000 deaths annually. Establishment of GAS infection is dependent on a suite of proteins exported via the general secretory pathway. Here, we show that GAS naturally produces extracellular vesicles with a unique lipid composition that are laden with proteins and RNAs. Interestingly, both virulence-associated proteins and RNA species were found to be differentially abundant in vesicles relative to the bacteria. Furthermore, we show that genetic disruption of the virulence-associated two-component regulator CovRS leads to an increase in vesicle production. This study comprehensively describes the protein, RNA, and lipid composition of GAS-secreted MVs and alludes to a regulatory system impacting this process.

Novel volatiles of skin-borne bacteria inhibit the growth of Gram-positive bacteria and affect quorum-sensing controlled phenotypes of Gram-negative bacteria

2016 ◽  
Vol 39 (8) ◽  
pp. 503-515 ◽  
Author(s):  
Marie Chantal Lemfack ◽  
Srinivasa Rao Ravella ◽  
Nicola Lorenz ◽  
Marco Kai ◽  
Kirsten Jung ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

MODELLING AGR-DEPENDENT QUORUM SENSING IN GRAM-POSITIVE BACTERIA

2014 ◽  
pp. 173-192
Author(s):  
S. JABBARI ◽  
J. R. KING ◽  
N. P. MINTON ◽  
K. WINZER
Keyword(s):  
Quorum Sensing ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals Optimal response to quorum-sensing signals varies in different host environments with different pathogen group size

2019 ◽  
Author(s):  
Liqin Zhou ◽  
Leyla Slamti ◽  
Didier Lereclus ◽  
Ben Raymond
Keyword(s):  
Bacillus Thuringiensis ◽  
Quorum Sensing ◽  
Social Interactions ◽  
Group Size ◽  
Social Evolution ◽  
Local Population ◽  
Gram Positive ◽  
Competitive Fitness ◽  
Oral Infections ◽  
Gram Positive Bacteria

AbstractThe persistence of genetic variation in master regulators of gene expression, such as quorum-sensing systems, is hard to explain. Here, we investigated two alternative hypotheses for the prevalence of polymorphic quorum-sensing in Gram-positive bacteria, i.e. the use of different signal / receptor pairs (‘pherotypes’) to regulate the same functions. First, social interactions between pherotypes or ‘facultative cheating’ may favour rare variants that exploit the signals of others. Second, different pherotypes may increase fitness in different environments. We evaluated these hypotheses in the invertebrate pathogen Bacillus thuringiensis, using three pherotypes expressed in a common genetic background. Facultative cheating occurred in homogenized hosts, in contrast, rare pherotypes had reduced fitness in naturalistic infections. There was clear support for environment-dependent fitness: pherotypes varied in responsiveness to signals and in mean competitive fitness. Notably, competitive fitness varied with group size: the pherotype with highest responsiveness to signals performed best in smaller hosts where infections have a lower pathogen group size. Less responsive pherotypes performed best in larger hosts. Results using homogenized insect media fit with the expectation of facultative cheating and social evolution theory, but results from naturalist oral infections do not fit many of the predictions from this body of theory. In this system, low signal abundance appears to limit fitness in hosts while the optimal level of response to signals varies in different host environments.ImportanceQuorum sensing describes the ability of microbes to alter gene regulation according to their local population size. Some successful theory suggests that this is a form of cooperation: investment in shared products is only worthwhile if there are sufficient bacteria making the same product. This theory can explain the genetic diversity in these signaling systems in Gram-positive bacteria such as Bacillus and Staphylococcus. The possible advantages gained by rare genotypes (which can exploit the products of their more common neighbours) could explain why different genotypes can coexist. We show that while these social interactions can occur in simple laboratory experiments they do not occur in naturalistic infections using an invertabrate pathogen, Bacillus thuringiensis. Instead our results suggest that different genotypes are adapted to different-sized hosts. Overall, social models are not easily applied to this system implying that a new explanation for this form of quorum sensing is required.

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