Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

N-acetylmuramoyl-L-alanine amidases are periplasmic hydrolases that cleave the amide bond between N-acetylmuramic acid and alanine in peptidoglycan. Unlike many Gram-negative bacteria that encode redundant periplasmic amidases, Vibrio fischeri appears to encode a single protein that is homologous to AmiB of V. cholerae We screened a V. fischeri transposon-mutant library for strains altered in biofilm production and discovered a biofilm over-producing strain with an insertion in amiB (VF_2326). Further characterization of biofilm enhancement suggested that this phenotype was due to over-production of cellulose, and it was dependent on the bcsA cellulose synthase. Additionally, the amiB mutant was nonmotile, perhaps due to defects in its ability to septate during division. The amidase mutant was unable to compete with wild type for colonization of V. fischeri's symbiotic host, the squid Euprymna scolopes In single-strain inoculations, host squid inoculated with the mutant eventually became colonized, but with much less efficiency than squid inoculated with wild type. This observation was consistent with the pleiotropic effects of the amiB mutation and led us to speculate that motile suppressors of the amiB mutant were responsible for partially restored colonization. In culture, motile suppressor mutants carried point mutations in a single gene (VF_1477), resulting in a partial restoration of wild-type motility. In addition, these point mutations reversed the effect of the amiB mutation on cellulosic biofilm production. These data are consistent with V. fischeri AmiB possessing amidase activity; they also suggest that AmiB suppresses cellulosic biofilm formation but promotes successful host colonization.Importance Peptidoglycan (PG) is a critical microbe-associated molecular pattern (MAMP) that is sloughed by cells of V. fischeri during symbiotic colonization of squid. Specifically, this process induces significant remodeling of a specialized symbiotic light organ within the squid mantle cavity. This phenomenon is reminiscent of the loss of ciliated epithelium in patients with whooping cough due to production of PG monomers by Bordetella pertussis Furthermore, PG processing machinery can influence susceptibility to anti-microbials. In this study, we report roles for the V. fischeri PG-amidase AmiB, including the beneficial colonization of squid, underscoring the urgency to more deeply understand PG processing machinery and the downstream consequences of their activities.
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PMID:Vibrio fischeri amidase activity is required for normal cell division, motility, and symbiotic competence. 3318 95