Meeting Abstract

86.8  Monday, Jan. 6 11:45  Aerobic indicators and vascular distribution in the bacteriogenic light organ of Euprymna tasmanica (Cephalopoda: Sepiolidae) PATELUNAS, A.*; NISHIGUCHI, M.K.; New Mexico State University; New Mexico State University nish@nmsu.edu

Symbiosis between the Southern dumpling squid, Euprymna tasmanica (Cephalopoda: Sepiolidae) and its luminescent bacterial symbiont, Vibrio fischeri, provides an experimentally tractable system to examine interactions between a eukaryotic host and its bacterial partner. V. fischeri luminescence provides light to the squid for a behavior termed “counterillumination,” which allows the squid to mask its shadow during downwelling moonlight, also known as silhouette reduction. Although this association is beneficial, light generated from the bacteria (via the lux operon) requires large quantities of oxygen to maintain this energy consuming reaction. Previous work has noted the presence of vascularization within the light organ, but the extent and location of these blood vessels remains unknown. Using serial section scanning electron and confocal laser scanning microscopy, we have examined the vascular network within the light organ of juvenile E. tasmanica. Morphological features, including vessel type, diameter, and location of vessels, were measured. Differences between squids that are infected with symbiotic V. fischeri compared to aposymbiotic squids will allow us to better predict whether the presence of V. fischeri influences the extent of vascular branching upon development. Additionally, this project seeks to identify if there is an increase in the metabolic stress on the squid via the production of anaerobically induced enzymes in squid tissue. Knowledge gained from this research will provide a framework to understand how beneficial bacteria influence the development of a closed vascular network, and will provide insight to the evolutionary dynamics that form mutualistic associations.