Complex intestinal bacterial communities in three species of Planorbid snails

The intestinal microbiota of animals play an important role in their energy metabolism and resist-ance to pathogens, and thus in maintenance of animals in their environment. We surveyed the intesti-nal microbiota of three species of Planorbidae (Gastropoda: Pulmonata). Cultivation-independent molecular methods were used to investigate the community composition of intestinal bacteria from individual snails: three Biomphalaria pfeifferi (Africa), two Bulinus africanus (Africa) and three Helisoma duryi (North America). PCR amplification and sequencing of 612 bacterial 16S rRNA genes yielded 282 unique DNA sequences (97 % sequence similarity) among the eight individual snails sampled. The observed bacterial diversity was distributed over 18 phyla, with the greatest number of 16S rRNA gene sequences derived from the Gammaproteobacteria, Bacteroidetes and Acidobacteria. These results document the presence of highly diverse gut bacterial communities in three snail species and indicate the need for additional study to determine the roles that gut microbes play in the physi-ology and immunology of planorbid snails