Characterization of  two host-specific genes, mannose-sensitive hemagglutinin (mshA) and uridyl phosphate dehydrogenase (UDPDH) that are involved in theVibrio fischeri–Euprymna tasmanica mutualism

Abstract

While much has been known about the mutualistic associations between the sepiolid squid Euprymna tasmanica and the luminescent bacterium, Vibrio fischeri, less is known about the connectivity between the microscopic and molecular basis of initial attachment and persistence in the light organ. Here, we examine the possible effects of two symbiotic genes on specificity and biofilm formation of V. fischeri in squid light organs. Uridine diphosphate-dehydrogenase (UDPDH) and mannose-sensitive hemagglutinin (mshA) mutants were generated in V. fischeri to determine whether each gene has an effect on host colonization, specificity, and biofilm formation. Both squid light organ colonization assays and transmission electron microscopy (TEM) confirmed differences in host colonization between wild-type and mutant strains, and also demonstrated the importance of both UDPDH and mshA gene expression for successful light organ colonization, and furthers our understanding of the genetic factors playing important roles in this environmentally transmitted symbiosis.

A genomic comparison of 13 symbiotic Vibrio fischeri isolates from the perspective of their host source and colonization behavior

“…For instance, type-4 pili (T4P) are a class of surface structures often associated with pathogenic or beneficial microbial colonization of host tissue (Craig et al, 2004;Dulla et al, 2012), and 10 distinct T4P gene clusters have been identified in V. fischeri strain ES114 (Ruby et al, 2005). Some of these putative pilus proteins (that is, MshA, PilT and PilA2) have been linked previously to the colonization process Ariyakumar and Nishiguchi, 2009;Chavez-Dozal et al, 2012). As expected, these pili are encoded in the genomes of all the light organ-derived strains (Table 2).…”

Predation Response of Vibrio fischeri Biofilms to Bacterivorus Protists

“…Moreover, biofilm communities offer a refuge toward diverse stresses, such as antibiotics (3)(4)(5), dehydration and osmotic stress (5,6), UV light exposure (6,7), and starvation (3). The pronounced stress resistance of biofilms has been observed to be prevalent in marine communities, particularly ones comprised of environmental Vibrio biofilms (2,8,9).…”

Bacterial Biodiversity in Natural Environments

“…It is understood that the bacterial symbionts are able to establish themselves within the host tissue by forming biofilm in the epithelium-lined crypts of the squid light organ. This was demonstrated by Ariyakumar & Nishiguchi (2009), where V. fischeri mutants with a reduced ability to form biofilm in vitro were unable to successfully colonize squid light organs and were not detected in any section of the crypt region. Biofilms are the leading cause of contamination of medical devices and in industrial and agricultural settings.…”