Anaerobic bacteria in the gut of terrestrial isopod crustaceanPorcellio scaber

Anaerobic bacteria fromPorcellio scaber hindgut were identified and, subsequently, isolated using molecular approach. Phylogenetic affiliation of bacteria associated with the hindgut wall was determined by analysis of bacterial 16S rRNA gene sequences which were retrieved directly from washed hindguts ofP. scaber. Sequences from bacteria related to obligate anaerobic bacteria from generaBacteroides andEnterococcus were retrieved, as well as sequences from ‘A1 subcluster’ of the wall-less mollicutes. Bacteria from the genusDesulfotomaculum were isolated from gut wall and cultivated under anaerobic conditions. In contrast to previous reports which suggested the absence of anaerobic bacteria in the isopod digestive system due to short retention time of the food in the tube-like hindgut, frequent renewal of the gut cuticle during the moulting process, and unsuccessful attempts to isolate anaerobic bacteria from this environment our results indicate the presence of resident anaerobic bacteria in the gut ofP. scaber, in spite of apparently unsuitable,i.e. predominately oxic, conditions.