Effects of a long-term rearing system for deep-sea vesicomyid clams on host survival and endosymbiont retention

Abstract

signals. Our results indicate that the artificial chemosynthetic aquarium system had specific effects on symbiont abundance and possibly on host survival. Furthermore, transmission electron microscopic observations of sulfur globules in the symbiont cells and expression analyses of the dsrA gene of the symbiont indicated that stocked elemental sulfur could be consumed as an energy source to reduce sulfide shortages. We discuss the importance of higher and more stable sulfide concentrations and the proportions of available O 2 and CO 2 in driving appropriate metabolic functions of the symbiont and improving the survival of the clams.Abstract Deep-sea vesicomyid clams, including the genus Phreagena, harbor obligate sulfur-oxidizing symbiotic bacteria in gill epithelial cells. Difficulty in maintaining Phreagena clams in rearing tanks has been a major obstacle to achieving a better understanding of their unique biology. To improve the method of rearing Phreagena clams, here we reared them in an artificial chemosynthetic aquarium and evaluated the effects of the aquarium system on long-term clam rearing. We compared the survival of clams reared in the artificial chemosynthetic tank with the survival of those in the normal tank, and analyzed the symbiont abundance using semi-quantification of fluorescent in situ hybridization Biology

Interdecadal Distribution of Persistent Organic Pollutants in Deep-Sea Chemosynthetic Bivalves

“…We also used the archived clams collected at a depth of 1,171 m (Dive #1074) during cruise NT10-01 (January 12-18, 2010) using the ROV Hyper-Dolphin operated by the R/V Natsushima (JAMSTEC), as well as at depths of 1205 m (Dive #2K0998) and 1,195 m (Dive #2K0450) during cruises NT98-06 (April 2-26, 1998) and N89-08 (October 7-29, 1989), respectively, using the HOV Shinkai 2000 operated by the R/V Natsushima (Table 1). These clams were preserved as whole at JAMSTEC at (Ikuta et al, 2018); however, we did not distinguish between these two species in this study. Bathymodiolus japonicus mussels were also collected from the seep site off Hatsushima Island at a depth of 901 m (Dive #6K1557), while Bathymodiolus septemdierum mussels were collected from hydrothermal vent sites at Myojin Knoll, Japan, at a depth of 1235 m (Dive #6K1556).…”

Molecular detection of a novel perkinsid associated with the deep‐sea clam Phreagena okutanii

“…The gill filaments of the P. okutanii specimens in which the organism in question was detected by PCR (sample no. H1773‐B1‐32 and H1773‐B1‐33) were used for FISH analyses, which were conducted as described previously (Fujinoki et al, 2012; Ikuta et al, 2018), with the following modifications. The fixed gills were embedded in paraffin and sliced into 10 μm transverse sections.…”