Putative environmental transmission of sulfur-oxidizing bacterial symbionts in tropical lucinid bivalves inhabiting various environments

Abstract

Four tropical lucinids, Codakia orbiculata, C. pectinella, Linga pensylvanica, which inhabit sea-grass beds, and Lucina pectinata, which inhabits mangrove swamps, harbor sulfur-oxidizing endosymbiotic bacteria within bacteriocytes of their gill filaments. To elucidate the symbiont transmission mode in these bivalves, symbiont-specific oligonucleotides were designed and used in polymerase chain reaction amplifications (PCR). For all species investigated, each primer set was unsuccessful in amplifying symbiont DNA targets from ovaries and testis, whereas successful amplifications were obtained from symbiont-containing gill tissue. These data suggest that the transmission mode is environmental, independently of the lucinid habitat, as it is in the other tropical lucinid Codakia orbicularis. (C) 1998 Published by Elsevier Science B.V. All rights reserved.