Bacterial Sensor Kinases: Diversity in the Recognition of Environmental Signals

Krell, Tino; Lacal, Jesús; Büsch, Andreas; Silva-Jiménez, Hortencia; Guazzaroni, María‐Eugenia; Ramos, Juan L.

doi:10.1146/annurev.micro.112408.134054

Cited by 313 publications

(296 citation statements)

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“…In AI-2 dependent multispecies biofilm communities, suppression of luxS gene expression is expected to lead to variation in interspecies behavior [170][171][172].…”

Section: Mutationsmentioning

confidence: 99%

Potential Emergence of Multi-quorum Sensing Inhibitor Resistant (MQSIR) Bacteria

et al. 2015

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Expression of certain bacterial genes only at a high bacterial cell density is termed as quorum-sensing (QS). Here bacteria use signaling molecules to communicate among themselves. QS mediated genes are generally involved in the expression of phenotypes such as bioluminescence, biofilm formation, competence, nodulation, and virulence. QS systems (QSS) vary from a single in Vibrio spp. to multiple in Pseudomonas and Sinorhizobium species. The complexity of QSS is further enhanced by the multiplicity of signals: (1) peptides, (2) acyl-homoserine lactones, (3) diketopiperazines. To counteract this pathogenic behaviour, a wide range of bioactive molecules acting as QS inhibitors (QSIs) have been elucidated. Unlike antibiotics, QSIs don't kill bacteria and act at much lower concentration than those of antibiotics. Bacterial ability to evolve resistance against multiple drugs has cautioned researchers to develop QSIs which may not generate undue pressure on bacteria to develop resistance against them. In this paper, we have discussed the implications of the diversity and multiplicity of QSS, in acting as an arsenal to withstand attack from QSIs and may use these as reservoirs to develop multi-QSI resistance.

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“…In AI-2 dependent multispecies biofilm communities, suppression of luxS gene expression is expected to lead to variation in interspecies behavior [170][171][172].…”

Section: Mutationsmentioning

confidence: 99%

Potential Emergence of Multi-quorum Sensing Inhibitor Resistant (MQSIR) Bacteria

et al. 2015

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“…Environmental adaptation. Optimal bacterial adaptation to an environment is strongly associated with the expression of a series of sensors/regulators (38,39). The L. casei genome contains 16 complete TCS and 124 transcriptional regulators contributing to its ability to sense and adapt to various environments (37).…”

Section: Significancementioning

confidence: 99%

Functional genomics of Lactobacillus casei establishment in the gut

Licandro

Scornec

Pédron

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Although the composition of the gut microbiota and its symbiotic contribution to key host physiological functions are well established, little is known as yet about the bacterial factors that account for this symbiosis. We selected Lactobacillus casei as a model microorganism to proceed to genomewide identification of the functions required for a symbiont to establish colonization in the gut. As a result of our recent development of a transposonmutagenesis tool that overcomes the barrier that had prevented L. casei random mutagenesis, we developed a signature-tagged mutagenesis approach combining whole-genome reverse genetics using a set of tagged transposons and in vivo screening using the rabbit ligated ileal loop model. After sequencing transposon insertion sites in 9,250 random mutants, we assembled a library of 1,110 independent mutants, all disrupted in a different gene, that provides a representative view of the L. casei genome. By determining the relative quantity of each of the 1,110 mutants before and after the in vivo challenge, we identified a core of 47 L. casei genes necessary for its establishment in the gut. They are involved in housekeeping functions, metabolism (sugar, amino acids), cell wall biogenesis, and adaptation to environment. Hence we provide what is, to our knowledge, the first global functional genomics analysis of L. casei symbiosis.commensalism | Lactic acid bacteria T he pioneering studies that led to the characterization of the gut microbiota were reviewed in 2001 (1). These studies and recent investigations have revealed mutualistic functions (2), including a barrier effect against allogenic microbes (3), fermentation of complex sugars (4, 5), and maturation and homeostasis of the immune system (6). Recent metagenomic studies have revealed an extraordinary diversity of genes constituting the gut microbiome (7), opening the way to correlative studies linking microbiome diversity, homeostasis, and diseases (5,8,9).In parallel, some representative species, i.e., "model symbionts," now are being studied functionally (10). As it was done for pathogens, it is essential to develop the cellular microbiology of symbionts and particularly to identify the genes required for their establishment and persistence in the gut. Transcriptomic profiling identified up-regulated genes linked to metabolic functions, stress responses, and pili synthesis during early colonization (11-13). Comparative genomics among Lactobacilli identified strain-specific candidate genes for extended colonization: In Lactobacillus rhamnosus, persistence was attributed to an spaCBA locus encoding LPXTG-like pilins (14), and in Lactobacillus johnsonii it was attributed to specific glycosyltransferases, a phosphotransfer system, and a protease (15). Otherwise, a functional in vivo screening based on the expression of a genomic library of Bacteroides fragilis identified a locus encoding polysaccharide utilization as essential for stable colonization of murine colonic crypts (16). Alternatively, colonization of germ-free mic...

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“…Prototypical two-component systems are composed of a sensor kinase and a response regulator, serving as a signal receptor and effector, respectively (2,3). Each component protein harbors distinct functional domains (4). Signal perception by the extracytoplasmic domain of the sensor kinase triggers autophosphorylation of a conserved His of the cytoplasmic dimerization and His phosphostransfer (DHp) domain.…”

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confidence: 99%