Bacterial quorum sensing: circuits and applications

Garg, Neera; Manchanda, Geetanjali; Kumar, Aditya

doi:10.1007/s10482-013-0082-3

Cited by 78 publications

(54 citation statements)

References 162 publications

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“…QS is used by bacteria to modulate gene expression patterns based upon population density. The process is mediated by diffusion of signal molecules (auto-inducers) that bind to appropriate receptors on target bacteria [55,56]. We observed no alteration in expression of any of the known QS genes ( qseC and qseB ) involved in LEE regulation in EHEC-strains, in co-culture compared to pure culture.…”

Section: Discussionmentioning

confidence: 82%

The Gut Bacterium Bacteroides thetaiotaomicron Influences the Virulence Potential of the Enterohemorrhagic Escherichia coli O103:H25

et al. 2015

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Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential.

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Section: Discussionmentioning

confidence: 82%

The Gut Bacterium Bacteroides thetaiotaomicron Influences the Virulence Potential of the Enterohemorrhagic Escherichia coli O103:H25

et al. 2015

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“…The Open Conference Proceedings Journal, 2016, Volume 7 17 quinolones, cyclic dipeptides, fatty acid esters and cyclic thiolactone are examples of AI molecules reflecting signal diversity [17]. Production and detection of most autoinducers are restricted to organisms within species.…”

Section: What About Biofilms On the Surface Of Stone Monuments?mentioning

confidence: 99%

“…The biofilm mode of life needs cell-cell communication systems for the regulation of multicellular behavior. These cell-cell communication systems are based on quorum sensing (QS) signal molecules termed autoinducers (AI) [17]. AI are small diffusible signal molecules produced proportionally to the population density of the producing organism.…”

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confidence: 99%

What About Biofilms on the Surface of Stone Monuments?

Martino¹

2016

Open Conf. Proceed. J.

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Bacteria can live either as free planktonic cells in bulk solution, or as sessile cells attached to a surface. In addition to their attachment status, sessile bacteria are part of sessile communities termed biofilms. A biofilm can be defined as a microbial community attached to a solid surface composed of cells organized as microcolonies embedded in an organic polymer matrix of microbial origin. Thus, a biofilm is made of microbial cells and extracellular polymeric substances. The biofilm mode of life provides several advantages to microorganisms including resistance to environmental stresses, increased communication and genetic exchange between cells. Microbial biofilm development can be observed on virtually all kinds of stone monuments such as castles, caves, churches/cathedrals, fountains, temples, tombs/catacombs, etc., and can be associated with problems of conservation. Several types of autotrophic and heterotrophic microorganisms are usually observed on stone monuments such as bacteria, fungi, algae and lichens. The European standard EN15898 defines the main general terms used in the field of conservation of cultural property such as alteration, deterioration, weathering, treatment and cleaning. The term biodeterioration is not defined in the EN15898 standard, but can be defined as "any undesirable change in the properties of a material caused by the vital activities of organism". The biodeterioration of stone materials corresponds to an aesthetic action (production of pigments), to a biochemical action (stone dissolution or salt crystallization driven by cell metabolism) and to a physical action (mechanical pressure during growth). This review has two main objectives: to summarize the actual knowledge about basics of microbial colonization and biodeterioration of stone monuments and to realize a quantitative and qualitative analysis of publications in scientific journals on this topic.Keywords: Biocleaning, biofilm, biodeterioration, monument, microorganisms, stone. DEFINITIONSBacteria can live either as free planktonic cells in bulk solution, or as sessile cells attached to a surface. Antonie van Leuwenhoek was the first scientist to observe sessile bacteria described as aggregates of 'animalcules" living at the human tooth surface. In addition to their attachment status, sessile bacteria are part of sessile communities termed biofilms. Since the pioneer study of Antonie van Leuwenhoek, much has been accomplished in understanding the specifics of the biofilm lifestyle. A biofilm can be defined as a microbial community attached to a solid surface composed of cells organised as microcolonies embedded in an organic polymer matrix of microbial origin. Thus, a biofilm is made of water, microbial cells and extracellular polymeric substances (EPS). Many EPS are highly hydrated but most of the water is not directly bound to the EPS [1,2]. EPS comprise both charged (i.e. positive or negative) and uncharged (i.e. neutral) biopolymers. All major classes of biological macromolecules, i.e., polysaccharide...

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“…Many microorganisms including many species of gram-positive and gram-negative bacteria, archaea, fungi and some algae are known to produce EPSs. These natural, nontoxic, and biodegradable polymers not only protect microorganisms against environmental extremes such as Antarctic ecosystems, saline lakes, geothermal springs, or deep-sea hydrothermal vents but also play important roles in various biological mechanisms such as immune response, adhesion, infection, and signal transduction (Jones et al 2014;Poli et al 2011;Kumar et al 2007;Sutherland 1998) as well as in biofilm formation, biofouling, and quorum sensing (Garg et al 2014;Fazli et al 2014). Some EPSs produced by microorganisms such as cellulose are also produced by higher-order plants.…”

Section: Introductionmentioning

confidence: 99%