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At least 631 records · Page 35Linked to original sources

PubMed1991

[Distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice].

Bromoacetamide show a high molluscicidal effect, low toxicity to fish and good solubility in water. It is a promising molluscicide. The present paper reported the distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice. Radioactivity in animals was measured by liquid scintillation counting. In Oncomelania snails the radioactivity gradually increased with exposure time and drug concentration. The highest level was found in the head-foot, reaching 12.5 x 10(3) dpm.mg-1 after exposure to the drug for 24 h, whereas the levels in liver and other tissue were 3.0 x 10(3) and 3.8 x 10(3) dpm.mg-1 respectively. Carps absorbed bromo[methylene-3H] acetamide similarly as in Oncomelania snails, but the levels in tissues were less than those in Oncomelania snails. Bromo[methylene-3H]acetamide 0.5 ml (1.4 mumol.L-1) was given ig to mice. Blood samples of 3 mice were collected at 0.5, 1, 3, 6, 12, 24 and 96 h after ig. The peak levels was found within 12 h and then declined gradually.

Acetamides↗

PubMed1991

[Features of the chlorine-dependent effect of acetylcholine and neutral amino acids on neurons of the Achatina snail].

Responses of neurons in cerebral ganglia of an African giant snail (Achatina fulica) to acetylcholine (ACh), gamma-aminobutyric acid (GABA) and glycine (Gly) were investigated. Cl-dependent currents induced by these mediators in neurons of one and a half month old snail sibs were inhibited by dibutyryl-cAMP and strychnine. Inhibition of ACh-responses by 10(-8) mol/l GABA was mimicked by applications of dibutyryl-cAMP and isobutylmethylxanthine. GABA- and Gly-responses exhibited complete cross-desensitization, but this effect was absent for ACh and GABA (or Gly). On the basis of pharmacological dependences of GABA- and Gly-responses it is suggested that these amino acids act on the same receptor-channel complex in neurons of young snails. ACh-, GABA- and Gly-induced chloride currents were independent in neurons of four years old snails.

Acetylcholine↗

PubMed1991

Miracidia of Schistosoma japonicum: approach and attachment to the snail host.

Schistosoma japonicum miracidia swim directed along a chemical gradient toward the snails Oncomelania hupensis and Biomphalaria glabrata, and they turn back when the concentration of attractive chemicals decreases. The host signal for this chemotactic response has a molecular weight of more than 30,000. When swimming miracidia encounter the surface of O. hupensis or agar containing O. hupensis snail-conditioned water (SCW) they perform the host-specific responses "contact with return," "repeated investigation," and "attachment," but they do not exhibit such behavior when encountering B. glabrata surface or agar containing B. glabrata SCW. Thus S. japonicum miracidia respond to different host signals when they approach snails than when they attach to snails.

Animals↗

PubMed1991

[Evaluation of molluscicidal effect of nicotinanilide against Oncomelania snails].

Both nicotinanilide hydrochloride and nicotinanilide sulfate are water-soluble, their IC50 and LC90 against Oncomelania snails being around 0.3 mg/L and 0.5 mg/L, respectively, during 24 hour exposure at 25 degrees C followed by a 7-day recovery period. The laboratory tests and field trials showed that over 90% of snails were killed within 3 days exposure at 1-2 mg/L, and that 18.4%-100% snails on moist soil were killed at over 20 degrees C, exposed to spraying dosage of 1-2 g/m2 for 1-3 days. The chemical is highly effective against snails eggs at early stage (cell stage). The LC50 of nicotinanilide to Aristichthys nobilis and Pseudorasbora parva is about 200 mg/L. The acute oral LD50 in mice is about 2 g/kg. Plants tolerate the chemical at 1-2 g/m2, but some leaves wilted at greater than or equal to 5 g/m2, dicotyledon in particular. Dermatitis has been reported in individuals frequently exposing to nicotinanilide wettable powder during massive spraying.

Animals↗

PubMed1990

Marking snails with numbered, colored discs: a technique for identifying individual specimens.

Numbered, colored discs, measuring 2.5 mm in diameter, were evaluated under laboratory conditions as tags for marking and identifying individual snails. Discs were affixed to the shells of specimens of Helisoma duryi (Pulmonata: Planorbidae) with an adhesive supplied with the discs and with waterproof epoxy. All snails survived the initial tagging procedure and showed no observable behavioral responses to the tagging. The supplied adhesive, intended for use with terrestrial insects, was inadequate for securing the tags for prolonged periods under aquatic conditions. Use of waterproof epoxy, however, resulted in 100% tag retention for over 5 months without significant mortality. The permanence of the marks, their coding of individuals, the rapidity and ease with which the tags can be applied without causing behavioral changes or snail mortality suggest that this technique will be useful in studies requiring identification of individual aquatic snails.

Adhesives↗

PubMed1990

A laboratory study of the toxicity of the butanol extract of endod (Phytolacca dodecandra) on two species of freshwater fish and two species of aquatic snails.

The purpose of this study was to evaluate the toxicity of the butanol extract of Endod (Phytolacca dodecandra) on 4 species of aquatic animals. Groups of 10 mosquito fish (Gambusia affinis) and 8 bluegill (Lepomis macrochirus) were exposed to the butanol extract of Endod in 300 ml of water at concentrations of 0.0, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2 or 2.0 ppm. Groups of 10 tropical snails (Biomphalaria glabrata) and 10 pond snails (Physa spp) were also exposed to the crude extract in 50 ml of water at concentrations of 0.0, 1.0, 1.5, 2.0, 2.2, 2.5, 3.0, 4.0 or 5.0 ppm. Following a 24-h exposure period, the test subjects were transferred to extract-free water and observed for an additional 24 h. The number of dead animals was determined after the total 48-h concentration was plotted on logarithmic (probit) graph paper and the concentration of Endod which killed 50% of the test subjects (LC50) was determined. The butanol extract of Endod was lethal to 50% of the fish and snails at relatively low concentrations (less than 3.0 ppm). The results also indicated that fish were approximately 2 to 4 times more sensitive to Endod than snails.

Animals↗

PubMed1990

Dual or single infection of the terrestrial snail Solatopupa similis (Bruguière, 1792) with two protostrongylid nematodes, Muellerius capillaris (Mueller, 1889) and Neostrongylus linearis (Marotel, 1913).

The land snails Solatopupa similis were experimentally infected with two protostrongylidae, Muellerius capillaris and Neostrongylus linearis. Although the apparent rate of penetration was always high (64-91%), infection remained low (less than 3 larvae/snail); most of the larvae that penetrated the snails did not develop into second stage larvae. Rates of snail mortality recorded in infected groups were higher than those observed in non infected snails.

Animals↗

PubMedDate not supplied

Food allergy to Helix terrestre (snail).

Among the rare foods capable of producing food allergies is the snail (Helix terrestre). The snail is a delicacy eaten in Spain, France and Portugal. This study presents the findings of an allergic study of 10 patients with this infrequent food allergy during the past 10 years. The shock organ in the majority (80%) of these patients was the bronchial tree. Six of them did not have any digestive or skin symptoms which are usually seen in cases of food allergy. All patients manifested the symptomatology after ingestion of Helix terrestre. Two also had reactions after eating Patella vulgata (limpet). The snail and the limpet are within the phylogenetic line of molluscs, i.e. of gastropods. All patients tolerated the ingestion of cephalopods and bivalves which belong to two other phylogenetic lines. Skin tests to seafoods (squids, prawns, lobsters and clams) were negative for all patients. This suggests that the sensitizing antigen is probably a protein found only in gastropod molluscs. Skin tests along with the histamine release test were valid diagnostic methods for this food allergy. The limited bibliography on this subject is probably due to the fact that the consumption of snails as well as limpets is limited to specific geographical areas.

Adolescent↗

PubMedDate not supplied

[The humoral link in the mechanism of formation of conditioned food refusal in the edible snail].

Effect was studied of hemolymph of snails-donors with conditioned food refusal, on learning the same habit by snails-recipients. Facilitation was observed of the recipients' learning depending on the quantity of injected hemolymph and the type of conditioned stimulus. The hemolymph of pseudo-conditioned donors inhibited the learning of intact snails-recipients. The possibility is suggested of appearance in the hemolymph of conditioned snails of one or several chemical factors, capable to facilitate elaboration of the same conditioned reflex.

Animals↗

PubMed1986

Influence of aerobic energy deficit, ouabain and harmaline on the phenylalanine and galactose active transport by snail intestine.

The effect of anaerobiosis (N2 bubbling of the medium) or 10(-4) M dinitrophenol on the penetration of 0.5 mM Phe in snail and rat everted intestine, in 2 min and 30 min incubation periods, has been studied. The aerobic energy deficit inhibits the amino acid net entry in both species, but whereas the active transport is annulled in rat, snail intestine is capable of continuing to accumulate Phe against a gradient. The prolonged action (30 min of preincubation) of 1 mM ouabain inhibits 0.1 mM Phe and 0.1 mM galactose entry in snail intestine. Amino acid uptake is far higher than the one obtained in the absence of Na+, in which condition Phe keeps accumulating against a gradient in the tissue water. Galactose active transport, instead, becomes null in the presence of the glucoside or in the absence of Na+. One mM harmaline is able to inhibit the initial entry of galactose into the tissue, while higher than 5 mM concentrations are required to inhibit that of Phe. Results confirm that snail intestine is capable of easily carrying out active transport processes with energy from anaerobic origin. On the other hand Phe transport is less sensitive to the absence of Na+, presence of ouabain or harmaline than that of galactose, so that contrary to what has been observed for the sugar, the active transport of the amino acid is not annulled in any of the three conditions.

Anaerobiosis↗

PubMed1985

Responses to odors mapped in snail tentacle and brain by [14C]-2-deoxyglucose autoradiography.

The method of 2-deoxyglucose (2-DG) autoradiography has been widely used to map functional neuronal systems in vertebrates, but in invertebrate species, where morphological dimensions favor its use, the applications have been minimal. This study uses [14C]-2-DG to map the olfactory system of a terrestrial snail, Achatina fulica. The olfactory organ in the snail's tentacles bears a striking resemblance to the vertebrate olfactory mucosa. There are also complex neural structures in the tentacle and brain that are devoted to subsequent processing. These facts make the molluscan olfactory system a suitable complement to the traditional vertebrate and insect models in olfaction. The experiments utilized intact snails in which one tentacle was exposed to a controlled odor environment while the contralateral tentacle was held in a retracted position. The dose of [14C]-2-DG (2 microCi/gm) was injected into the hemocele. Tissue processing involved freeze-substitution with acetone, dry sectioning, and the preparation of liquid film autoradiographs. Optical density measurements permitted quantitative comparisons between experimental conditions. The natural odors of conspecific snails and of carrots elicited significantly more uptake of 2-DG in the exposed tentacle than in the unexposed tentacle and, in the exposed tentacle, significantly more label over the axons of the primary sensory neurons than was elicited by exposure to clean air. Amyl acetate and octanol were less effective. A small number of superficially placed sensory neurons were labeled in all stimulus conditions, including clean air, and may represent the mechanosensors. Stimulus-dependent labeling in the brain was limited to the procerebrum and included both neuropilar and cellular parts. In contrast to vertebrate and insect olfactory systems, there was no evidence of spatial coding for odor quality.

1-Octanol↗

PubMed1979

Comparison of carbon and nitrogen content of infected and uninfected snails, Succinea ovalis, and the trematode Leucochloridium variae.

In June, 6.7% of adult Succinea ovalis collected near Urbana, Ohio, were infected with the trematode, Leucochloridium variae. The effects of parasitism were assessed as total organic carbon (equivalent to calorific values) and as total nitrogen. The parasite represents 23.8% of total (parasite + snail tissue) dry tissue weight, 21.4% of total carbon and 19.8% of total nitrogen of infected snails. The higher C : N ratio for parasite tissue indicates a higher proportion of nonproteinaceous compounds (e.g., fats and/or carbohydrates) as compared to host tissue. There is less snail tissue in parasited S. ovalis. The C : N ratios for parasitized and nonparasitized snail tissue suggest identical percentage compositions of proteins, fats, and carbohydrates.

Animals↗

PubMed1979

Excretion, accumulation and site of synthesis of urea in the snail Pila globosa during active and dormant periods.

The pattern of urea excretion in active and dormant phases of the amphibious Indian apple snail, Pila globosa, as well as the possible site and mechanism of urea synthesis in this animal have been studied. 1. Urea may be synthesized in the hepatopancreas of this snail and excreted through the nephridia with the nephridial fluid during the active period of the animals life. In dormant snails, this metabolic excretory waste accumulates in its various organs and body fluids. 2. The possibility of the presence of an ornithine cycle for the synthesis of urea in the hepatopancreas is indicated in this snail.

Amino Acids↗

PubMed1979

Pharmacological effects of the giant African snail Achatina fulica.

The body fluid and tissue extract of the foot of Achatina fulica, the edible giant African snail, were investigated and quantified for pharmacological effects. Both reduced spontaneous locomotor activity in mice, protected them from death from amphetamine induced toxicity, prolonged hexobarbitone sleeping time and caused a depletion of catecholamines from various organs of the rat. From this a central depressant action combined with an antihypertensive effect is inferred. This is in keeping with the objectives of local traditional healers who use the snail on their patients. It is suggested that eledoison, a potent antihypotensive agent found in aquatic snails may also be present in terrestrial snails such as Achatina.

Animals↗

PubMed1979

Susceptibility of Iraqi fresh water snails to infection with Schistosoma haematobium and Schistosoma mansoni Egyptian strains.

A great number of Egyptian workers and farmers are seeking settlement in Iraq and some of them proved to have either Schistosoma Haematobium (S.h.) or Schistosoma mansoni (S.m) or even mixed infection. Besides, there is the possibility that some of the Iraqi fresh water snails may prove to be susceptible to infection by one or both of the Schistosoma Egyptian strains. The present study deals with investigations on the susceptibility of Iraqi B. truncatus, Gyranaulus ehrenbergi, Physa c.f. fontinalis, Lymnea lagetis, Melanoides tuberculata and Melanopsis nodes by these parasites. Egyptian S. haematobium but not Egyptian S. mansoni infect Iraqi B. truncatus and both proved to be unable to infect any of the other snails included in the study. Yet, the number of cercariae shedded by B. truncatus snails infected with the Egyptian S. haematobium strain, was much less that the number of cercariae shedded by these snails when infected with the Iraqi S. Haematobium strain.

Animals↗

PubMed1981

Interactions between St. Lucian Biomphalaria glabrata and Helisoma duryi, a possible competitor snail, in a semi-natural habitat.

In artificial drains similar to those used in banana culture on St. Lucia, Helisoma duryi, the rams-horn snail, controlled Biomphalaria glabrata, intermediate host of schistosomiasis on that island. Time required for elimination of B. glabrata depended on environmental temperature and numbers of H. duryi initially introduced in the drains. Best fit to the data was given by the equation for the logistic curve rather than by an equation for unlimited growth. Multiple regression analyses of natality and mortality rates of both species of snails indicated that populations of B. glabrata were regulated by temperature rather than by density-dependent means while numbers of H. duryi were strongly influenced by numbers of rams-horn snails already present in the drains. Fitting of snail shell growth to von Bertalanffy equations showed that H. duryi shell diameter was uninfluenced by environmental temperatures or presence of B. glabrata while growth of the intermediate host was strongly affected both by temperature and numbers of H. duryi.

Animals↗

PubMed1978

Palatability studies of snail and slug poison baits, using dogs.

In 1975, the California Department of Food and Agriculture required registered manufacturers of snail and slug baits to present data showing the unattractiveness of these products to dogs, in order to reduce the number deaths in dogs due to poisoning by eating these baits. A cooperative project involving the University of California, the California Department of Food and Agriculture, and the snail and slug bait manufacturers was designed to assist the manufacturers in assessing the palatability of their products by dogs and to develop criteria for the regulatory agencies to use to ensure that the products they were registering were unattractive to dogs. The studies showed that most recently formulated baits were relatively unpalatable for dogs. A 2-panel consumption testing procedure was developed and is being used by the California Department of Food and Agriculture and the Environmental Protection Agency as criteria for registration. Current reports indicate a dramatic decrease in snail and slug bait poisonings in California after these criteria were established as requirements for registration of snail and slug baits.

Acetaldehyde↗

PubMed1978

Freshwater snail consumption and angiostrongyliasis in Malaya.

A survey of the freshwater snails, Pila scutata and Bellamyia ingallsiana, as food consumed by the local population was carried out in Peninsular Malaysia. Of these two species the first is preferred; the sizes favoured are between 25--40 mm. Pila snails were found to be consumed by the three communities, viz. Malay, Chinese and Indian, in different ways. The various methods of preparing the snails for consumption are described. P. scutata is an intermediate host of the rat-lung worm, Angiostrongylus malaysiensis. As this worm presumably is the causative agent of human eosinophilic meningoencephalitis, the eating habits of the three races in consuming the snail in relation to the epidemiology of the disease was also discussed.

Animals↗