Microbes and Environments
Online ISSN : 1347-4405
Print ISSN : 1342-6311
Regular Paper
Identification of Endosymbionts in Oligobrachia mashikoi (Siboglinidae, Annelida)
Norihiro KubotaMasaaki KanemoriYuichi SasayamaMasato AidaYoshihiro Fukumori
Author information

2007 Volume 22 Issue 2 Pages 136-144


Oligobrachia mashikoi, a frenulata, is a marine invertebrate living in an unusual habitat in Tsukumo Bay (20-25 m deep), Japan. It lacks a mouth and a gut, and instead possesses specialized cells called bacteriocytes, in which endosymbiotic bacterial cells are kept. The endosymbiosis involves specific interactions and obligatory metabolic exchanges between the host and endosymbiotic bacterial cells. Analyses of 16S rRNA genes from the endosymbiotic cells indicated that there are at least seven phylotypes of endosymbionts in O. mashikoi, and these phylotypes are closely related Gammaproteobacteria among which sequence homology was more than 97.6%. The analyses suggested that an adult worm predominantly accommodates one of the seven phylotypes. In situ hybridization targeting 16S rRNA demonstrated that the distribution patterns of the bacterial cells in adult worms were very similar among at least two phylotypes of the endosymbionts. The findings suggest that O. mashikoi has a strict selection mechanism for its endosymbiont.

Information related to the author
© Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology
Previous article Next article