An attempt to clarify the diets of olive flounder and bigfin reef squid juveniles using PNA clamping

Abstract

 Peptide nucleic acid (PNA)-directed PCR clamping was used to efficiently detect prey animals in the predators' stomach. Two oligo PNAs (19 and 18 mer) having sequences specific to the 16S rDNAs of olive flounder Paralichthys olivaceus and bigfin reef squid Sepioteuthis lessoniana were designed. PCR amplification of the 16S rDNAs of these species was successfully inhibited in the presence of these PNAs. This method was applied to DNAs extracted from the stomach contents of olive flounder and bigfin reef squid juveniles caught in Tsuruga Bay, Japan. Goby DNAs were detected in nine of 11 flounder juveniles examined, and DNAs of the Japanese anchovy Engraulis japonicus and the Japanese silver-biddy Gerres oyena were detected in each of the remaining founder juveniles. Anchovy DNA was also detected in two of nine squid juveniles, while fish species could not be identified for short sequences (118 bp) obtained from the other squid juveniles.