this guide to the identification of iranian freshwater snails has been prepared with aim of helping individuals involved in field work, but who have had no specialized training in taxonomy to differentiate snail specimens which they collect to certain groups by means of simple identification key. the guide pays special attention to the principal snail groups which transmit human schistosomiasis...

Lymnaea stagnalis were operantly conditioned to not perform aerial respiratory behaviour in a specific context (i.e. context-1). The memory for this learned response was reactivated 3 days later in context-1. During the 1 h reconsolidation period following memory reactivation, randomly picked snails were either maintained in context-1 or exposed to a new context (i.e. context-2). One hour later...

Social isolation is often considered to have negative effects on cognitive function in a wide range of species. Here we assess how environmental context alters the effect of isolation on long-term memory formation (24 h) in the pond snail Lymnaea stagnalis. We operantly trained snails to reduce aerial respiration in hypoxia following exposure to one of three social conditions: (1) maintained an...

L I G H T microscopical investigations of the neurones of pulmonate gastropods reveal that certain nerve-cells contain neurosecretory droplets. This has been observed in Basommatophora (Grzycki, 1951; Lever, 1957, 1958; Lever, Kok, Meuleman, andjoosse, 1961 ;Wautier, Pavans de Ceccatty, Richardot, Buisson, and Hernandez, 1961) and in stylommatophoran slugs, such as Limax, Milax, and Arion (Herl...

The phenomenon of dart shooting in several species of land snails has still not been explained. We were interested in whether the dart can function as a nuptial gift of calcium, as previously proposed. Donating calcium would increase the fitness of the offspring and thereby result in a higher reproductive success for the donor. We confirmed in Helix aspersa that the developing embryo takes up c...

The function of the love dart in certain species of terrestrial snails is unknown. In Helix aspersa, the dart is a sharp calcareous structure that is used to pierce the partner's skin during courtship. When expelled, the dart is covered with a thick mucus. The hypothesis tested here is that the mucus contains a biologically active substance. Extracts of the digitiform glands that produce this m...

Conantokin-G and conantokin-T are two paralytic polypeptide toxins originally isolated from the venom of the fish-hunting cone snails of the genus Conus. Conantokin-G and conantokin-T are the only naturally occurring peptidic compounds which possess N-methyl-D-aspartate receptor antagonist activity, produced by a selective non-competitive antagonism of polyamine responses. They are also structu...

A strong molluscicidal effect of sanguinarine against Oncomelania hupensis snails was demonstrated by immersion test in the present study. A positive relationship between doses, immersion time and the mortality of the snails was exhibited, while the optimal dose and immersion time of application towards the field eradication of snails were suggested. The possible mechanisms of effects were expl...

Thin-layer chromatography was used to analyze the free-pool amino acids of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata infected with Echinostoma caproni and uninfected (control) snails. Qualitative analysis revealed the presence of histidine, lysine, serine, alanine, valine, and isoleucine or leucine in all samples. Quantitative analysis of lysine and valine gave mean weigh...