Role of GbpA protein, an important virulence‐related colonization factor, for Vibrio cholerae's survival in the aquatic environment

Abstract

Vibrio cholerae N-acetyl glucosamine-binding protein A (GbpA) is a chitin binding protein and a virulence factor involved in the colonization of human intestine. We investigated the distribution and genetic variations of gbpA in 488 V. cholerae strains of environmental and clinical origin, belonging to different serogroups and biotypes. We found that the gene is consistently present and highly conserved including an environmental V. cholerae-related strain of ancestral origin. The gene was also consistently expressed in a number of representative V. cholerae strains cultured in laboratory aquatic microcosms under conditions simulating those found in temperate marine environments. Functional analysis carried out on V. cholerae O1 El Tor N16961 showed that GbpA is not involved in adhesion to inorganic surfaces but promotes interaction with environmental biotic substrates (plankton and bivalve hepatopancreas cells) representing known marine reservoir or host for the bacterium. It is suggested that the ability of GbpA to colonize human intestinal cells most probably originated from its primary function in the aquatic environment.

Effects of Global Warming onVibrioEcology

“…Salinity of 1.5% and temperatures ranging from 25°C to 30°C have been shown to be important in influencing the attachment of V. cholerae to copepods (76,77). A possible explanation for this comes from recent studies (78,79) evaluating the expression of two major V. cholerae adhesins involved in interactions with zooplankters and chitin substrates [N-acetyl glucosamine-binding protein A (GbpA) and mannose-sensitive hemagglutinin (MSHA)] in aquatic microcosms. Experiments conducted at different temperatures (15°C, 20°C, and 25°C), matching the seasonal temperature range of temperate marine environments, showed a significant increase in expression level of both adhesins at 25°C.…”

Vibrio cholerae GbpA elicits necrotic cell death in intestinal cells

“…Sequencing analysis of the 488 V. cholerae strains, originating from different cholera-affected regions in the world, suggests that the gbpA gene is highly conserved within the species (Stauder et al, 2012). Interestingly, the gene is also present in environmental strains belonging to other Vibrio spp.…”

Interactions ofVibriospp. with Zooplankton

“…with chitin is the GlcNAc-binding protein A (GbpA). This protein is important for binding to the chitinous exoskeletons of zooplankton, such as copepods and cladocerans, as well as to egg sacs and fecal matter (103,104) (Fig. 3).…”

“…GbpA-encoding genes have been detected in all V. cholerae strains tested (clinical and environmental). as well as some pathogenic Vibrio species including V. alginolyticus, V. vulnificus and V. parahaemolyticus (104). A mutation of GbpA in V. cholerae resulted in a 10-fold reduction in binding to Daphnia exoskeletons (103).…”

“…30-fold compared to the wild type (20) and the mutant was shown to be less adhesive towards the exoskeleton and egg sac of plankton than the gbpA mutant. This indicates that the MSHA pilus is more important for attachment to plankton than GbpA (104). This bacterium possesses another type IV pilus, the chitin-regulated pilus (ChiRP) encoded by pilA, whose expression is induced by GlcNAc.…”