Polymerase Chain reaction and 16S rRNA gene sequences from the luminous bacterial symbionts of two deep-sea anglerfishes

Sequences of the 16S ribosomal RNA gene of luminous bacterial symbionts from the escas of the deep sea anglerfishesMelanocetus johnsoniandCryptopsaras couesiwere determined by direct sequencing of polymerase chain reaction products. A sequence was also obtained from a strain ofPhotobacterium phosphoreum, the culturable light organ symbiont ofOpisthoproctus grimaldii. Comparison of these and other published sequences showed that the anglerfish symbionts group with the marine luminous bacteria but are not closely related toP. phosphoreum. The two ceratioid symbionts differ from each other at least at the species level.