The <i>cadA</i> gene of <i>Vibrio cholerae</i> is induced during infection and plays a role in acid tolerance

Merrell, D. Scott; Camilli, Andrew

doi:10.1046/j.1365-2958.1999.01650.x

Cited by 169 publications

(201 citation statements)

References 52 publications

(94 reference statements)

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“…The induction of the V. fischeri ATR was monitored by assaying resistance to killing by exposure to a pH 4.5 mixture of SCFA for 20 min (54). To obtain symbiotic V. fischeri for the ATR assay, we collected a homogenate of either central-core tissues from individual adult (>4-wk-old) squid light organs or 50 whole juvenile (2-d-old) squid; both preparations were suspended at ∼10 7 cfu/mL.…”

Section: Methodsmentioning

confidence: 99%

The chemistry of negotiation: Rhythmic, glycan-driven acidification in a symbiotic conversation

Schwartzman

Koch

Heath‐Heckman

et al. 2014

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

113

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Glycans have emerged as critical determinants of immune maturation, microbial nutrition, and host health in diverse symbioses. In this study, we asked how cyclic delivery of a single host-derived glycan contributes to the dynamic stability of the mutualism between the squid Euprymna scolopes and its specific, bioluminescent symbiont, Vibrio fischeri. V. fischeri colonizes the crypts of a host organ that is used for behavioral light production. E. scolopes synthesizes the polymeric glycan chitin in macrophage-like immune cells called hemocytes. We show here that, just before dusk, hemocytes migrate from the vasculature into the symbiotic crypts, where they lyse and release particulate chitin, a behavior that is established only in the mature symbiosis. Diel transcriptional rhythms in both partners further indicate that the chitin is provided and metabolized only at night. A V. fischeri mutant defective in chitin catabolism was able to maintain a normal symbiont population level, but only until the symbiotic organ reached maturity (∼4 wk after colonization); this result provided a direct link between chitin utilization and symbiont persistence. Finally, catabolism of chitin by the symbionts was also specifically required for a periodic acidification of the adult crypts each night. This acidification, which increases the level of oxygen available to the symbionts, enhances their capacity to produce bioluminescence at night. We propose that other animal hosts may similarly regulate the activities of epithelium-associated microbial communities through the strategic provision of specific nutrients, whose catabolism modulates conditions like pH or anoxia in their symbionts' habitat.symbiosis | squid-vibrio | metabolism | chitin

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Section: Methodsmentioning

confidence: 99%

The chemistry of negotiation: Rhythmic, glycan-driven acidification in a symbiotic conversation

Schwartzman

Koch

Heath‐Heckman

et al. 2014

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

113

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“…In addition, RIVET enabled the identification of Vibrio cholerae cadA as a gene induced during infection of mice (174). Vibrio cholerae is only weakly resistant to acid stress, and it was originally thought not to possess an acid tolerance response.…”

Section: Genes Involved In Adaptation To Environmental Stressesmentioning

confidence: 99%

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

Rediers

Rainey

Vanderleyden

et al. 2005

Microbiol Mol Biol Rev

140

120

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A major challenge for microbiologists is to elucidate the strategies deployed by microorganisms to adapt to and thrive in highly complex and dynamic environments. In vitro studies, including those monitoring genomewide changes, have proven their value, but they can, at best, mimic only a subset of the ensemble of abiotic and biotic stimuli that microorganisms experience in their natural habitats. The widely used gene-to-phenotype approach involves the identification of altered niche-related phenotypes on the basis of gene inactivation. However, many traits contributing to ecological performance that, upon inactivation, result in only subtle or difficult to score phenotypic changes are likely to be overlooked by this otherwise powerful approach. Based on the premise that many, if not most, of the corresponding genes will be induced or upregulated in the environment under study, ecologically significant genes can alternatively be traced using the promoter trap techniques differential fluorescence induction and in vivo expression technology (IVET). The potential and limitations are discussed for the different IVET selection strategies and system-specific variants thereof. Based on a compendium of genes that have emerged from these promoter-trapping studies, several functional groups have been distinguished, and their physiological relevance is illustrated with follow-up studies of selected genes. In addition to confirming results from largely complementary approaches such as signature-tagged mutagenesis, some unexpected parallels as well as distinguishing features of microbial phenotypic acclimation in diverse environmental niches have surfaced. On the other hand, by the identification of a large proportion of genes with unknown function, these promoter-trapping studies underscore how little we know about the secret lives of bacteria and other microorganisms

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“…Total RNA was harvested from strains grown in LB broth at 2 h, 4 h and 8 h as described previously (Merrell and Camilli, 1999). A 344 bp ompT riboprobe template was generated by PCR using primers OmpTF (5¢-ATTGGTTCTGGTTCT TCG-3¢) and OmpTR (5¢-TTTGCATTATCTTCTGGA-3¢).…”

Section: Rnase Protection Assaysmentioning

confidence: 99%

“…A 344 bp ompT riboprobe template was generated by PCR using primers OmpTF (5¢-ATTGGTTCTGGTTCT TCG-3¢) and OmpTR (5¢-TTTGCATTATCTTCTGGA-3¢). The amplification product was ligated to pGEM-T (Promega), proper orientation was confirmed and the riboprobe was synthesized using the Maxiscript kit (Ambion) and 50 mCi of [ 32 P]-UTP (NEN) as described previously (Merrell and Camilli, 1999). RPAs were done using the RPAII kit with 1 mg of RNA as described by the manufacturer (Ambion).…”

Section: Rnase Protection Assaysmentioning

confidence: 99%

ToxR interferes with CRP‐dependent transcriptional activation of ompT in Vibrio cholerae

Merrell

Camilli

et al. 2002

Molecular Microbiology

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SummaryIn pathogenic Vibrio cholerae, the transmembrane DNA-binding protein ToxR co-ordinates the expression of over 20 genes, including those encoding important virulence factors such as cholera toxin and the toxin-co-regulated pilus. The outer membrane protein OmpT is the only member of the ToxR regulon known to be repressed by ToxR. In this study, we examined the environmental conditions that regulate OmpT expression and demonstrated that ompT transcription is upregulated 14-fold when the bacteria enter late log phase from early log phase. Deletion of the crp gene completely abolishes OmpT expression. Comparison of ompT transcription levels in the isogenic crp -, toxR -and crp -toxR -mutants revealed that (i) in the absence of ToxR, constitutive high-level ompT transcription is dependent on cAMP receptor protein (CRP); (ii) ToxR not only interferes with CRPdependent ompT activation, but also abolishes the CRP-independent, basal level ompT transcription; thus, the mechanism by which ToxR represses ompT transcription involves both antiactivation and direct repression; (iii) both CRP and ToxR are required for the regulation of OmpT expression by growth phase. To provide further insights into the molecular mechanism of CRP-dependent activation of ompT transcription, we demonstrated that CRP-dependent activation requires a CRP binding site centred at -310 of the ompT promoter, without which the interaction of CRP with other CRP binding site(s) more proximal to the promoter results in repression. Mutations in two regions on CRP (AR1 and AR2) that directly

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The cadA gene of Vibrio cholerae is induced during infection and plays a role in acid tolerance

Cited by 169 publications

References 52 publications

The chemistry of negotiation: Rhythmic, glycan-driven acidification in a symbiotic conversation

The chemistry of negotiation: Rhythmic, glycan-driven acidification in a symbiotic conversation

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

ToxR interferes with CRP‐dependent transcriptional activation of ompT in Vibrio cholerae

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