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 ...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 phycoerithrin(light absorption,fluorescence emission,and electrophoresis of the protein moieties)while cyanobacterial cells(Nostoc sp.)showed evidence of C-phycocyanin and allophycocyanin.The possible phylogenetic and functional significance of the pigments present in the C endosymbiont is discussed.展开更多
The digestive gland of the apple snail Pomacea canaliculata lodges two types of pigmented corpuscles(identified as C and K corpuscles)which has been proposed as endosymbiont/s.Both corpuscular types are always present...The digestive gland of the apple snail Pomacea canaliculata lodges two types of pigmented corpuscles(identified as C and K corpuscles)which has been proposed as endosymbiont/s.Both corpuscular types are always present in the digestive gland of adult snails,they are released into the tubuloacinar lumen and are later expelled in the feces.On their part,hatchlings lack any C or K corpuscles in the digestive gland as well as in their feces,whereas C corpuscles appear in both the gland and feces within one week after hatching.Hence,it is possible that the detritivorous hatchlings acquire the putative C-endosymbiont from feces in the sediments where they live,i.e.through‘lateral’or‘horizontal’transmission.This possibility was put to test in an experiment in which we prevented any lateral transmission,by a 7-days aseptic culture,with no food,of aseptically obtained hatchlings.At the end of the experiment,we observed that most juveniles had survived the culture period,and hence the digestive glands and feces of survivors were studied by light microscopy of resin embedded,toluidine blue-stained sections.All studied glands and fecal samples showed C corpuscles.It is concluded that lateral transmission of the endosymbiont,if any,is not indispensable for the acquisition of the endosymbiont by hatchlings.展开更多
基金supported by grants from FONCyT,CONICET and the National University of Cuyo.
文摘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 phycoerithrin(light absorption,fluorescence emission,and electrophoresis of the protein moieties)while cyanobacterial cells(Nostoc sp.)showed evidence of C-phycocyanin and allophycocyanin.The possible phylogenetic and functional significance of the pigments present in the C endosymbiont is discussed.
文摘The digestive gland of the apple snail Pomacea canaliculata lodges two types of pigmented corpuscles(identified as C and K corpuscles)which has been proposed as endosymbiont/s.Both corpuscular types are always present in the digestive gland of adult snails,they are released into the tubuloacinar lumen and are later expelled in the feces.On their part,hatchlings lack any C or K corpuscles in the digestive gland as well as in their feces,whereas C corpuscles appear in both the gland and feces within one week after hatching.Hence,it is possible that the detritivorous hatchlings acquire the putative C-endosymbiont from feces in the sediments where they live,i.e.through‘lateral’or‘horizontal’transmission.This possibility was put to test in an experiment in which we prevented any lateral transmission,by a 7-days aseptic culture,with no food,of aseptically obtained hatchlings.At the end of the experiment,we observed that most juveniles had survived the culture period,and hence the digestive glands and feces of survivors were studied by light microscopy of resin embedded,toluidine blue-stained sections.All studied glands and fecal samples showed C corpuscles.It is concluded that lateral transmission of the endosymbiont,if any,is not indispensable for the acquisition of the endosymbiont by hatchlings.
