Showing papers on "Biomphalaria alexandrina published in 2008"

Synthesis and Molluscicidal Activity of Phosphorus-Containing Heterocyclic Compounds Derived from 5,6-Bis (4-bromophenyl)-3-hydrazino-1,2,4-triazine

Abstract: Novel N1-(phosphoryl moiety)-N2-(1,2,4-triazin-3-yl)hydrazines 4, 6, 8, 9 and 12, iminophosphorane 3, iminophosphane 5, 1,2,4-triazinyldiazaphospholine 7, 1,2,4,3-triazaphospholinotriazines 2, 10, 11, and 1,2,4-triazino[3,2-c][1,2,4,5] triazaphosphine 13 have been obtained via treatment 5,6-bis(4-bromophenyl)-3-hydrazino-1,2,4-triazine (1) with various polyfunctional phosphorus reagents by stirring at room temperature or refluxing for long time in tetrahydrofuran. Structures of these compounds have been deduced upon the basis of elemental and spectral data. Molluscicidal activity of the prepared compounds against Biomphalaria Alexandrina snails (the intermediate host of Schistosoma mansoni) showed considerable activities.

Molluscicidal and schistosomicidal activities of a steroidal saponin containing fraction from Dracaena fragrans (L.).

Abstract: The steroidal saponin-containing fraction from methanolic extract of Dracaena fragrans (Family: Agavaceae) was tested for molluscicidal and ovicidal activities against Biomphalaria alexandrina and Bulinus truncatus, the snail vectors of Schistosoma mansoni and S. haematobium in Egypt, respectively. It was also tested for schistosemicidal activity in vitro on adult S. mansoni and against the free-living miracidia and cercariae of the parasite. The homogenated soft body of B. alexandrina was used to determine the effect of the saponin fraction on total protein, albumen, aminotransferase enzymes and acetylcholin esterase. The results showed that the saponin fraction had considerable molluscicidal activity; LC50 & LC90 were 2.7 ppm & 3.7 ppm for B. alexandrina and 2 ppm & 2.5 ppm for B. truncatus, respectively. Snail eggs did not hatch in concentration as low as half molluscicidal LC50 (1.35 ppm). The LC50 killed all miracidia and cercariae in 30 seconds and after 22 & 40 minutes at a very low concentration (0.165 ppm) respectively, and had in vitro lethal effect on adults with LC50 18.4 microg/ml 4 days post-exposure. The snail tissue homogenate showed significant increase in total protein content & albumen, in aminotransferases and acetylcholinesterase activities.

Determination of allozyme, protein and schistosome susceptibility in Biomphalaria alexandrina progenies produced by self and cross fertilization.

Abstract: The mating system of B. alexandrina was studied under laboratory condition by allozyme analysis and SDS-PAGE protein analysis for parent snails and their progenies of two successive generations produced by self and cross fertilization. Allozyme analysis detected 11 genetic loci in 3 enzymes; ACP (3 loci), LDH (2 loci) and EST (6 loci). The mean number of Allele (A), average heterozygosity over loci (H) and dendrogram from cluster analysis based on genetic distances between snail groups showed a genetic heterogeneity in parents and 1st generation higher than that in the 2nd generation. Cross-fertilization and genetic heterogeneity among snails decreased through generations. Snails practiced self-fertilization showed genetic alterations and genetic heterogeneity was either decreased or increased. SDS-PAGE profile of tissue protein revealed that the mating system in B. alexandrina showed specific bands, 204 & 214 KDa, in snails bred by self-fertilization. D value based on shared protein bands number and estimated similarity between parents and progenies showed that parents were approximately similar with self and cross progenies in 1st generation and only with cross progenies in 2nd generation as self progenies showed increase or decrease in similarity. B. alexandrina susceptibility to S. mansoni was not affected when snails were bred by cross or self fertilization.

Molluscicidal saponins from leaves of Hedera canariensis.

Abstract: Activity-guided fractionation of the methanol extract of Hedera canariensis (var. Gloire de Maringo) Wild leaves afforded five saponins 1-5. Chemical and spectral methods (MS, 1HNMR, 13CNMR) showed that they are glycosides of hederagenin and oleanolic acid. The results showed that 4,5 exhibited molluscicidal properties, compound 1 was inactive. Mortality rate of exposed snails increased by increasing plant extract concentration. Lymnaea cailliaudi was more sensitive to plant extract than Biomphalaria alexandrina. The histopathological study revealed distinct damage in the structure of the stomach and ovotestis of treated L. cailliaudi snails. Saponin content was determined in term of haemolytic index.

Can the freshwater crayfish (Procambarus clarkii) help control schistosomiasis and fascioliasis in Egypt

Abstract: ab experiments and field survey have been carried out to investigate the impact and the relationship between the exotic crayfish; Procambarus clarkii and Schistosoma and Fasciola vector snails in Egypt. In the Lab, several species of freshwater snails, fish and aquatic plants were reported to serve as food for the freshwater crayfish. In the field, a survey for the crayfish and freshwater snails has been conducted at several irrigation channels in Qalyobiya, Ismailia and Behera governorates, which had been previously surveyed during 1990s. The results of the experimental Lab indicated that the vector snails; Biomphalaria alexandrina, Bulinus truncatus and limnaea natalensis were the preys of first choice for the crayfish. The field surveys showed high reduction and sometimes complete disappearance of vector snails in irrigation channels, which have been invaded by Procambarus clarkii, while in water courses which do not harbor the crayfish, such as El Manayef drain and Fayed canal (West of Suez Canal), high densities of these vector snails were recorded. The present study is providing encouraging indication of the possible overcoming schistosomiasis and fascioliasis in Egypt by the freshwater crayfish Procombarus clarkii.

Discrimination between susceptible and non-susceptible Biomphalaria alexandrina snails -intermediate hosts of Schistosoma mansoni in Western Saudi Arabia -using random amplified polymorphic DNA analysis

Abstract: Eight samples from infected and susceptible and from non-susceptible snails (Biomphalaria alexandrina) to Schistosoma mansoni infection were used in this study. Snails samples were studied at the genotypic level by RAPD analysis with two arbitrary primers. The genetic distances between samples were measured by the percentage of unshared bands. The studied samples separated into two groups according to their DNA fingerprinting. Thus this study has shown that the RAPD markers method has proved useful in discrimination between susceptible and non-susceptible snails of Biomphalaria alexandrina.