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THE STABILITY OF CHLOROPLASTS FROM SIPHONACEOUS ALGAE IN SYMBIOSIS WITH SACOGLOSSAN MOLLUSCS
Author(s) -
TRENCH ROBERT K.,
OHLHORST SHARON
Publication year - 1976
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1976.tb01442.x
Subject(s) - chloroplast , biology , algae , rubisco , photosynthesis , botany , biochemistry , acetabularia , carbon fixation , symbiosis , chlorophyta , bacteria , gene , genetics
SUMMARY Chloroplasts from siphonaceous algae remain photosynthetically active in the digestive epithelial cells of the sacoglossan opistobranchs Elysia viridis and Tridachia crispata for up to 3 months. During this time, chlorophylls and glycolipids are not synthesized, but the synthesis of small molecular weight metabolites such as sugars, amino acids etc. can readily be demonstrated. Analysis of the capacity of symbiotic chloroplasts to synthesize ribulose diphosphate carboxylase and membrane proteins produced negative results in both instances, even though photosynthetic CO 2 fixation could always be demonstrated. These findings show that symbiotic chloroplasts are biochemically stable entities, and that they neither grow nor divide while in the animals’cells. It it likely that chloroplasts depend on the plant cell nucleus and cytoplasmic protein synthesizing machinery for the synthesis of many of their structural and enzymatic components.