Isolation of functional chloroplasts from the sacoglossan mollusc Elysia viridis Montague

Abstract

SUMMARYA novel technique has been developed in which functional chloroplasts have been isolated and purified from the symbiotic sacoglossan mollusc Elysia viridis, Montague. This entailed the progressive filtration and gel‐filtration of a hyaluronidase‐incubated homogenate. Isopycnic centrifugation of the resultant crude chloroplast suspension reduced the cytoplasmic/mitochondrial and microbody contamination by approx. 70 and 90% respectively. Purified chloroplast suspensions were capable of linear rates of 14CO2 fixation for at least 25 min at 50 μmol m2 s−1 (PPFD), even though approx. 54% of assimilate was being released into the bathing medium. Values for CO2 fixation and assimilate release were similar to those obtained for the intact mollusc.