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

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.