Snail Helisoma

For measuring the bioaccumulation of " Tc in fishes and snails a small experimental freshwater pond was spiked with " I c. The concentration factors based on the calculated body burden (fresh wt) for carps Caprinus carpio), mosquitofishes Gam-busia affinis). and snails (Helisoma sp.) were 11, 75, and 121, respectively. ITic effective biological half-lives were 2,5,4.3 and 21.3 d. respectively [69]. 

Little direct evidence for chemotropism is available for invertebrates, due largely to the fact that tissue/organ culture systems have not been developed and exploited to the same extent as in vertebrates. Hay don et al. (1984) have shown that neurons of the snail Helisoma respond to exogenous application in vitro of the neurotransmitter serotonin by retraction of their growth cones. However, the precise role of this substance in vivo has yet to be determined (see Section 4.1). 

Kater and co-workers, working with identified neurons of the snail Helisoma in vitro, have shown that environmental factors can act to inhibit neurite extension rather than to stimulate it. The neurotransmitter serotonin, when added to the culture medium surrounding these neurons, causes an immediate cessation of neurite elongation (Haydon et al., 1984). This effect is associated with the direct inhibition of growth cone motile activities and the retraction of filopodia and lamellipodia, as shown by focal applications of serotonin to the growth cone with a micropipette. It has since been shown that the action of serotonin may be more complex, as it can stimulate neurite outgrowth if applied to... 

Identified neurons from the buccal ganglia of the snail Helisoma were placed into tissue culture and exposed to various treatments which resulted in a focal (Davenport and Kater, 1992) or global change in [Ca +]j (Rehder and Kater, 1992). Tran-... 

HT-lHel Helisoma snail AAQ95277 Database only... 

Ponder, E.L., Fried, B., and Sherma, J., 2004. Thin-layer chromatographic analysis of hydrophilic vitamins in standards and from Helisoma trivolvis snails. Acta Chromatographica. 14 70-81. 

Steiner et al. (1998) used HPTLC to analyze amino acids in water conditioned by several medically important snails—Biomphalaria glabrata, Helisoma trivolvis, and Lymnaea elodes. Snail-conditioned water (SCW) provides information value (in the form of pheromones) to attract larval trematode parasites. The SCW samples were dried with air and reconstituted in 10% -propanol and then applied to cellulose HPTLC plates and developed with n-propanol-water (7 3). Amino acids were detected with ninhydrin reagent and the resulting color sample zones were compared to known standards. The amino acids present in SCW (h/ p values and color reactions with ninhydrin given in parentheses) were as follows an unknown (7, purple), aspartic acid (21, purple), serine (29, purple), alanine (40, purple), tryptophan (51, purple), valine (58, purple/orange), phenylalanine (64, light blue), and leucine (69, purple). The above amino acids were detected in the SCW of all the snails, except that phenylalanine was not detected in Lymnaea elodes. 

Conaway et al. (1995) extended the above-mentioned study of Perez et al. (1994) to determine by densitometric-HPTLC sugars in Helisoma trivolvis snails infected with the larval trematode Echinostoma trivolvis. Zarzycki et al. (1995) examined the retention properties of alpha-, beta-, and gamma-cyclodextrins using water-wettable RP-C-18 layers and mobile phases composed of acetonitrile, methanol, ethanol, or propanol with water or methanol in acetonitrile. Esaiassen et al. (1995) analyzed n-acetylchitooligosaccharides by use of the latroscan TLC/ flame ionization detection (FID) system. Brandolini et al. (1995) used automated multiple development (AMD)-HPTLC to monitor various carbohydrates—i.e., maltotetraose, maltotriose, maltose, glucose, and fructose—in different beers. 

Sherma et al. (1992) used TLC to identify and quantify lutein and P-caro-tene from acetone extracts of snail bodies in two strains of Helisoma trivolvis (Colorado and Pennsylvania) snails and in the Biomphalaria glabrata snail. TLC of the snail extracts on Cjg (Whatman) reversed-phase layers developed in petroleum ether-acetonitrile-methanol (2 4 4) showed a fast moving zone Ry = 0.08) identical to a P-carotene standard. Scanning of in situ spectra confirmed pigment identities. The ratio of P-carotene to lutein was 1.1 in both strains of Helisoma trivolvis, but about 4.5 in Biomphalaria glabrata. The p-carotene to lutein ratio may be useful in the chemotaxonomy of planorbid snails. 

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