Neutral lipids and phospholpids in the apple snail
have been determined in the whole body, digestive gland-gonad complex (DGG), viscera, head-foot, shell, operculum, plasma, and hemocytes by high-performance thin-layer chromatography on silica gel plates. Plates were developed with petroleum ether-diethyl ether-glacial acetic acid, 80 + 20 + 1 (
), as mobile phase and sprayed with 5% phosphomolybdic acid to detect neutral lipids. Plates were developed with chloroform-methanol-water, 65 + 25 + 4 (
), and sprayed with 10% cupric sulfate to detect phospholipids. Triacylglycerols, free sterols, free fatty acids, steryl esters, phosphatidylcholine, and phosphatidylethanolamine were the major lipid fractions detected in the whole body, DGG, viscera, and head-foot. The major lipid fractions in the shell and operculum were free sterols and free fatty acids. The plasma and hemocytes contained free fatty acids as the major lipid fraction. The presence of these lipids suggests they are important to the metabolism and structure of the snail.
HPTLC analysis has been used to compare neutral lipid profiles in the urine of humans and mice. Neutral lipids and ubiquinone were extracted from urine with chloroform-methanol, 2:1, and determined on silica gel plates with 19 lanes and a concentration zone that were developed with petroleum ether-diethyl ether-glacial acetic acid, 80:20:1. Separated zones were detected with phosphomolybdic acid reagent and quantified by visible mode slit-scanning densitometry at 610 nm. Specific detection reagents were used to confirm the identity of particular lipid classes. The studies confirmed the presence of free sterols, free fatty acids, and triacylglycerols in both human and mouse urine. Methyl esters were found in mouse but not human urine. Hydrocarbons and ubiquinone were present in both human and mouse urine, but were not quantified. Similarities in the urinary neutral lipid profiles of humans and mice suggest that mice may serve as effective models for studies of the effects of infectious and metabolic diseases in humans.
Biomphalaria glabrata snails were infected with Schistosoma mansoni and maintained at different dilutions of artificial ocean water for up to 4 weeks. Glucose and maltose concentration of the digestive gland-gonad complex were analyzed by high-performance thin-layer chromatography at different stages of the infection. B. glabrata snails were divided into three experimental groups: Group A, snails with early prepatent infection (10 days post-infection); Group B, snails with late prepatent infection (22 days post-infection); and Group C, snails with patent infection (45 days post-infection). Infected snails in A were maintained at different salinities for 2 weeks and then necropsied, and their two main simple sugars, i.e., glucose and maltose, were analyzed. Groups B and C contained two subgroups: the first subgoups were analyzed after 2 weeks, and the second after 4 weeks. Controls for these experiments were maintained identically in either deionized water or artificial spring water. Maltose and glucose were extracted from the digestive gland-gonad complex in ethanol-water (70:30). 1-Butanol-glacial acetic acid-diethyl ether-deionized water (27:18:5:3) mobile phase was used to separate sugars on EMD Millipore silica gel preadsorbent plates. Sugars were detected using α-naphthol-sulfuric acid reagent and quantified with a CAMAG TLC Scanner 3 at 515 nm. The obtained data were compared using analysis of variance (ANOVA) single factor statistical analysis. Statistical differences were not found in any sugars in Group A snails. For glucose, a significant difference was found after 4 weeks in both B and C snails. For maltose, a significant difference was found after 4 weeks in B snails and after 2 weeks in C snails. Different salinity levels affect the maltose and glucose concentrations of adult B. glabrata snails infected with S. mansoni.
This review examines the use of thin-layer chromatography (TLC) for the analysis of neutral lipids and phospholipids in medically and economically important gastropod molluscs (snails). It discusses methods for isolating lipids from snails, and the use of layers, mobile phases, and detection reagents for the TLC analysis of snail neutral lipids and phospholipids. Quantitative densitometric studies are reviewed, with particular emphasis on class separations of neutral lipids and phospholipids. The review considers significant findings on the effects of diet and larval trematode parasitism on lipids in snails as determined by TLC.