Meeting Abstract

P1.19  Jan. 4  Gut microbial communities in the estuarine bivalves Geukensia demissa and Crassostrea virginica. LOGGANS, D.E.**; BIESIOT, P.M.; WANG, S.Y.; The University of Southern Mississippi

The ribbed mussel Geukensia demissa is a dominant intertidal bivalve commonly found in salt marshes along the east coast of the United States and the Gulf of Mexico. Previous studies have shown that G. demissa utilizes detrital lignocellulose derived from Spartina alterniflora to meet 26-80% of its carbon requirements whereas the eastern oyster Crassostrea virginica assimilates less than 3%. We hypothesize that differences in the gut microflora of the bivalves contribute to the observed variation in the digestion of refractory organic detritus. To determine components of the gut microbial community in these bivalves, universal primers specific for bacteria were used to PCR amplify the 16S ribosomal RNA gene, which was then cloned. Sequence results from the clone libraries indicate that the two bivalve species have different gut bacterial communities. Mycoplasma spp. dominate in the gut of G. demissa. Other gut bacteria included Enterococcus faecium, Epulopiscium sp., Lactobacillus zeae, Streptacidiphilus sp., and Synechococcus sp. In contrast, Acinetobacter sp., Anaplasma sp., Desemzia incerta, Gaetbulimicrobium brevivitae, Massilia sp., Salmonella sp., and several uncultured proteobacteria were found in C. virginica but not Mycoplasma. Current efforts are focused on determining whether the gut isolates are cellulolytic.