Helisoma

HT-lHel Helisoma snail AAQ95277 Database only... 

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-... 

Davenport, R.W. and Kater, S.B. (1992) Local increases in intracellular calcium elicit local rilopodial responses in Helisoma neuronal growth cones. Neuron 9 405-416. 

Goldberg, J.I. and Kater, S.B. (1989) Expression and function of the neurotransmitter serotonin during development of the Helisoma nervous system. Dev. Biol. 131 483-495. 

Phenylmercuric acetate Helisoma campanulata 4.75 Inorganic mercury (98) Ethyl mercury (2) Methyl mercury (trace) 0.59 Fang (1973)... 

Isol. from various molluscs incl. Helisoma trivolvis and Lymnaea stagnalis. Cardioregulatory neuropeptide. Hydrochloride 1 2) [115993-58-3]. 

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. 

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