Use of 16S rDNA community fingerprints to study cricket hindgut microbial communities

A nucleic acid-based method was evaluated in the course of a study of microbial community structure in the cricket hindgut. Genomic DNA was extracted from the hindgut microbial community of Acheta domesticus and used as a template in the polymerase chain reaction (PCR) method, using primers that align to well conserved regions of the 16S rRNA gene. The rDNA-PCR product was used as a community probe to generate restriction fragment length polymorphisms (RFLPs) of hindgut bacterial isolates and gut microbial communities of insects fed different diets. Fingerprints of the bacterial isolates consisted of several bands suggesting multiple rRNA operons. In contrast with soil communities, hindgut community RFLP contained distinguishable band patterns. However, community rDNA fingerprints were complex and varied among insects fed similar diets, suggesting considerable intrinsic variability in the hindgut microbial community structure between crickets regardless of dietary regime. These results suggest that community RFLP methods using broad-specific phylogenetic probes do not have the resolution or specificity required to ascertain the effect of diet on the cricket hindgut microbial community structure.