A study of chlorophyll-like and phycobilin pigments in the C endosymbiont of the apple- snail Pomacea canaliculata

Abstract

Pigments present in the brown-greenish C morph of an intracellular endosymbiont of Pomacea canaliculata were investigated. Acetone extracts of the endosymbiotic corpuscles showed an absorption spectrum similar to that of chlorophylls. Three fractions obtained from silica gel column chromatography of the acetone extracts (CI, CII and CIII), were studied by positive ion fast atom bombardment mass spectrometry (FAB?MS) and hydrogen-nuclear magnetic resonance (H-NMR). Results indicated the presence of (1) a sterol in the yellow colored CI fraction; (2) a mixture of pheophorbides a and b in the major green fraction, CII,; and (3) a modified pheophorbide a in the smaller green fraction, CIII. Aqueous extracts of the C endosymbiont did not show evidence of the occurrence of C-phycocyanin, allophycocyanin or phycoeritrin(light absorption, fluorescence emission, and electrophoresis of the protein moieties) while Nostoc sp. cells showed evidence of C-phycocyanin and allophycocyanin. The possible phylogenetic and functional significance of these pigments in this endosymbiotic organism/organelle is discussed.