Meeting Abstract

28.11  Jan. 5  Identification of luminescent symbionts from the genera Uroteuthis, Loliolus, and Euprymna (Mollusca: Cephalopoda) GUERRERO-FERREIRA, R.C.*; NISHIGUCHI, M.K.; New Mexico State University; New Mexico State University ricardo@nmsu.edu

Luminescent bacteria in the family Vibrionaceae (Bacteria: γ-Proteobacteria) are commonly found in complex, bilobed light organs of sepiolid and loliginid squids. Although morphology of these organs in both families of squids is similar, the species of bacteria which inhabit each host has yet to be verified. We utilized sequences of 16S ribosomal RNA, luciferase α-subunit (luxA) and the glyceraldehyde-3-phosphate dehydrogenase (gapA) genes to determine phylogenetic relationships between 63 strains of Vibrio bacteria, which included representatives from different environments as well as unidentified luminescent isolates from loliginid and sepiolid squid from Thailand. A combined phylogenetic analysis was used including biochemical data such as carbon use, growth and luminescence. Results demonstrated that certain symbiotic Thai isolates found in the same geographical area were included in a clade containing bacterial species phenotypically suitable to colonize light organs. Moreover, strains isolated from a particular squid host were found phylogenetically related to more than one bacteria species in our phylogeny. This research presents evidence of species of bacteria that have not been previously described as symbiotic strains colonizing light organs of Indo-West Pacific loliginid and sepiolid squids, and supports the hypothesis of a non-specific association between sepiolid and loliginid squids and marine luminescent bacteria.