Costs that individuals incur through mating can play an important role in understanding the evolution of life histories and senescence, particularly in promiscuous species. Copulation costs, ranging from energy expenditure to reduced longevity, are widely studied in insects but have received substantially less attention in other taxa. One cost of mating, the energetic cost, is poorly studied ac...

The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the lig...

The symbiosis polysaccharide locus, syp, is required for Vibrio fischeri to form a symbiotic association with the squid Euprymna scolopes. It is also required for biofilm formation induced by the unlinked regulator RscS. The syp locus includes 18 genes that can be classified into four groups based on putative function: 4 genes encode putative regulators, 6 encode glycosyltransferases, 2 encode ...

Vibrio fischeri are bioluminescent marine bacteria that can be isolated from their symbiotic animal partners or from ocean water. A V. fischeri population increases exponentially inside the light organ of the Hawaiian bobtail squid (Euprymna scolopes) while the host is quiescent during the day. This bacterial light organ population reaches stationary phase and then remains high during the night...

Reflectins are a unique group of structural proteins involved in dynamic optical systems in cephalopods that modulate incident light or bioluminescence. We describe cloning, structural characterization, and optical properties of a reflectinbased domain, refCBA, from reflectin 1a of Hawaiian bobtail squid, Euprymna scolopes. Thin films created from the recombinant protein refCBA display interest...

LBP [LPS (lipopolysaccharide)-binding protein] and BPI (bactericidal/permeability-increasing protein) are components of the immune system that have been principally studied in mammals for their involvement in defence against bacterial pathogens. These proteins share a basic architecture and residues involved in LPS binding. Putative orthologues, i.e. proteins encoded by similar genes that diver...

We studied the Euprymna scolopes-Vibrio fischeri symbiosis to characterize, in vivo and in real time, the transition between the bacterial partner's free-living and symbiotic life styles. Previous studies using high inocula demonstrated that environmental V. fischeri cells aggregate during a 3 h period in host-shed mucus along the light organ's superficial ciliated epithelia. Under lower inocul...

Colonization of the Hawaiian squid Euprymna scolopes by the marine bacterium Vibrio fischeri requires the symbiosis polysaccharide (syp) gene cluster, which contributes to symbiotic initiation by promoting biofilm formation on the surface of the symbiotic organ. We previously described roles for the syp-encoded response regulator SypG and an unlinked gene encoding the sensor kinase RscS in cont...

Bacteria often use transcription factors to regulate the expression of metabolic genes in accordance to available nutrients. NagC is a repressor conserved among γ-proteobacteria that regulates expression of enzymes involved in the metabolism of N-acetyl-glucosamine (GlcNAc). The polymeric form of GlcNAc, known as chitin, has been shown to play roles in chemotactic signaling and nutrition within...

Vibrio fischeri is the exclusive symbiont residing in the light organ of the squid Euprymna scolopes. To understand the genetic requirements for this association, we searched a library of V. fischeri transposon insertion mutants for those that failed to colonize E. scolopes. We identified four mutants that exhibited severe defects in initiating colonization. Sequence analysis revealed that the ...