Showing papers on "Biomphalaria alexandrina published in 2000"

Sublethal concentration of Ambrosia maritima(Damsissa) affecting compatibility of Biomphalaria alexandrina snails to infection with Schistosoma mansoni through disturbing the glycolytic pathway.

Abstract: High glycolytic flux as an emergency pathway for generating ATP was recorded as the most important metabolic pathway required for the success of Biomphalaria-Schistosome sporocyst interaction. Effect of LC25 of dry powdered Ambrosia maritima (Damsissa) as plant molluscicide on hexokinase (HK), pyruvate kinase(PK), glucose phosphate isomerase(GPI) was tested. It resulted in a significant inhibition of the three investigated enzymes. Treatment of snails with LC10 concentrations of A. maritima reduced considerably the infection rate of Biomphalaria alexandrina with Schistosoma mansoni to be 34% compared to an infection rate of 80% in control non-treated snails. Longer prepatent period and remarkable decrease in cercarial production was also recorded in snails treated with the sublethal concentrations of this molluscicide.

Susceptibility of Biomphalaria alexandrina to infection with Schistosoma mansoni: correlation with the activity of certain glycolytic enzymes.

Abstract: The importance of the glycolytic flux for the success of Biomphalaria-Schistosome sporocyst interaction was acertained in this study. Hexokinase (HK), pyruvate kinase(PK), glucose phosphate isomerase(GPI) and lactate dehydrogenase (LD) as four important glycolytic enzymes were markedly stimulated in trematode infected Biomphalaria alexandrina when measured two weeks post exposure to infection with Schistosoma mansoni miracidia. On the other hand phosphoenolpyruvate carboxy kinase (PEPCK), glucose-6-phosphatase (G6Pase) and fructose 1,6 diphosphatase(FDPase) as three gluconeogenic enzymes were slightly affected which confirm the importance of the glycolytic pathway for schistosome-exposed snails. Effect of LC25 of Solanum nigrum leaves dry powder as plant molluscicide on HK, PK and GPI were tested. Treatment with this plant resulted in a significant inhibition of these three investigated enzymes. LC10 concentrations of S. nigrum reduced considerably the infection rate of B. alexandrina with S. mansoni to be 34% compared to an infection rate of 80% in control, non-treated snails. Longer prepatent period and remarkable decrease in cercarial production was also recorded in snails treated with the sublethal concentrations of the molluscicide. As conclusion, susceptibility of B. alexandrina to infection with the digenetic trematode S. mansoni is correlated to the activity levels of the glycolytic enzymes. Moreover, sublethal and less pollutant concentration of S. nigrum could be recommended to control schistosomiasis by disturbing the intramolluscan environment of the parasite.

SDS-PAGE-separated tissue proteins of Biomphalaria alexandrina snails in the presence and absence of Schistosoma mansoni.

Abstract: SDS-PAGE was used to separate tissue proteins of control and trematode-infected Biomphalaria alexandrina snails. The separated profiles demonstrate the occasional appearance of protein fractions and the remarkable increase of concentration of certain molecular masses in infected snails at one week interval over four weeks post exposure to Schistosoma mansoni. Proteins of molecular masses of 44, 56, 65 and 144 KDa were among these occasionally appeared protein masses. Post exposure to S. mansoni larval infection, a protein mass of 36 KDa was predominant giving a markedely higher absorbance (> 1) compared to control (0.0166). This was identified as lactate dehydrogenase enzyme. Moreover, a protein of 56 KDa mass was identified as Pyruvate kinase. The predicted induction of these two enzymes could be either of host and/or parasitic origin. This study revealed that S. mansoni- B. alexandrina complex has a completely different protein pattern compared to control with very low similarity coefficient "S" value. A correlation between the snail tissue protein or separation patterns and the metabolic redirection of the snail host by the developing sporocyst was discussed.

Bioactivity of Anagallis arvensis and Calendula micrantha plants, treated with ammonium nitrate, superphosphate and potassium sulphate fertilizers, on Biomphalaria alexandrina.

Abstract: The survival rate of B. alexandrina snails maintained in aqueous solutions of the two tested plants (Calendula micrantha and Anagallis arvensis) decreased gradually with time until the 9th week and 10th week where the survival rate was zero in the high concentration of A. arvensis and C. micrantha, respectively, meanwhile, the survival rate of the control was 20%. Also, the two plants caused reduction in hatchability of snails egg masses. Thus, the percent of hatching in A. arvensis (82 ppm) was 46% and in C. micrantha was 72% compared with control (97.29%). Both plants reduced the infection rate of Biomphalaria alexandrina snails with Schistosoma mansoni miracidia to 41.17% and 61.9%, respectively, compared with control (90%). C. micrantha caused much higher reduction in snail infection rate than A. arvensis. The prepatent period was significantly prolonged in snails maintained at higher concentration of both plants. The cercarial output (expressed as mean number/snail) revealed that, A. arevensis caused a significant reduction in cercarial production than control. While, high concentration (120 ppm) of C. micrantha caused a significant elevation in the mean number of cercariae/snail. However, the total number of cercariae produced by all snails in each group showed a reverse relation with the tested concentrations in both plants.

Laboratory studies on the molluscicidal and cercaricidal activities of commiphora molmol.

Abstract: Purified oil and oieo - resin extracts of the Arabian or Somali gum Commiphora molmol (family: Burseraceae) were used as plant molluscicides against the vector snails Biomphalaria alexandrina, Bulinus truncatus and Lymnaea nataiensis. The results indicated that oil extract possesses a higher molluscicidal potency than the oleo-resin. The mortality rate of exposed snails was increased by prolongation of the exposure time. The LC50 values for the oil extract against Lymnaea ncnalertsis were quite lower than (hose utilised with H. alexandrine and B, trunvaius. These values were 5. 4 & 3 ppm. for exposure periods of 24, 48 & 96 hours respectively. Conversely, the oleo - resin extract showed a more pronounced cercaricidal potency than the oil. Total death of cercariae was remarked after 1/4 h of exposure to 10. 5 & 2.5 ppm.

Synthetic approaches towards benzo[h]quinoline-3-carbonitriles.

Abstract: 2-Alkoxybenzo[h]quinoline-3-carbonitriles 2 were readily synthesized via Dimroth rearrangement of 2-amino-4-aryl-5,6-dihydro-4H-naphtho[1,2-b]pyran-3-carbonitriles 5 induced by ethanolic and methanolic KOH. Compounds 2 were also obtained by the reaction of 2-arylmethylidene-3,4-dihydro-1(2H)-naphthalenones 1 with malononitrile or of ylidenemalononitriles 4 with 1,2,3,4-tetrahydro-1-naphthalenone in ethanolic and methanolic KOH. The molluscicidal activity of the products towards Biomphalaria alexandrina snails was screened.

Synthetic Approaches Towards Benzo[h]quinoline-3-carbonitriles.

Abstract: 2-Alkoxybenzo[h]quinoline-3-carbonitriles 2 were readily synthesized via Dimroth rearrangement of 2-amino-4-aryl-5,6-dihydro-4H-naphtho[1,2-b]pyran-3-carbonitriles 5 induced by ethanolic and methanolic KOH. Compounds 2 were also obtained by the reaction of 2-arylmethylidene-3,4-dihydro-1(2H)-naphthalenones 1 with malononitrile or of ylidenemalononitriles 4 with 1,2,3,4-tetrahydro-1-naphthalenone in ethanolic and methanolic KOH. The molluscicidal activity of the products towards Biomphalaria alexandrina snails was screened.

Discriminant analysis of free fatty acids of some Egyptian snails as a step for schistosomiasis control: new trends.

Abstract: Schistosomiasis is still the most common occupational health problem of rural workers in Egypt. The use of molluscicides, either chemical or biological, and environmental changing are the most successful methods of snail control. The new trend in Schistosoma control programs is to study the ecological factors that attract miracidium Schistosoma specific snails, to emphasizing to find out new environmental safe control methods. Since Schistosoma worms do not make fatty acids de novo, they require host lipids for survival and to complete their life cycle. Discriminate analysis of the estimated free fatty acids was done in this study in Biomphalaria alexandrina, Biomphalaria glabrata, and Bulinus truncatus, viz. Lymnaea truncatula and Physa acuta (Schistosoma intermediate and non-intermediate respectively). With the objective of determination of the biochemical difference that attract the infestation of Schistosoma miracidium to the target snails, as a step of the new control trends. Caprylic acid (C8:0), and Oleic acid (C18:1) are significantly lower in the tissues of Schistosoma intermediate snails compared to the non-intermediate snails. While, Capric acid (C10:0), Margaric acid (C17:0), and Lenoleic acid (C18:2) of the intermediate snails are significantly higher than that of non-intermediate snails. The percent of correct medical classification of snails are more than 80% according to Caprylic acid, Margaric acid, and Lenoleic acid, the other 15 fatty acids are less than 80%. These three free fatty acids could be chemoattractive of Schistosoma miracidium, and could be used as safe environmental control compounds, which needs further research.