THIN-LAYER CHROMATOGRAPHY AND HISTOCHEMISTRY ANALYSES OF NEUTRAL LIPIDS IN HELISOMA-TRIVOLVIS INFECTED WITH 4 SPECIES OF LARVAL TREMATODES

Thin-layer chromatography (TLC) and histochemistry studies were done o n the neutral lipid content of the digestive gland gonad (DGG) complex of Helisoma trivolvis infected with four species of larval trematodes . Two of the species, Ribeiroia sp. and Zygocotyle lunata, contained r ediae, and the two others, Spirorchis sp. and an armatae xiphidiocerca ria, contained sporocysts. The DGG infected by each species had its ow n distinct neutral lipid profile as determined by TLC. All profiles di ffered from that of the uninfected DGG. Densitometric TLC studies show ed some quantitative differences in free sterols in infected versus un infected DGGs. Visual observations of the chromatograms showed that al l four species caused a marked elevation in the triacylglycerol fracti on in the DGG as compared with the uninfected controls. Oil Red O (ORO ) histochemistry studies showed that levels of neutral lipids were inc reased in the DGGs of infected versus uninfected samples. These histoc hemistry studies showed a variable distribution of neutral fat, rangin g from its absence in the cercariae of Z. lunata and the armatae xiphi diocercaria to ORO-positive droplets in the excretory system of Ribeir oia sp. Rediae and sporocysts contained ORO-positive material in the b ody wall and in the space between cercariae.