Effect of Basudin, Selecron and the phytoalkaloid Colchicine (pesticides) on biological and molecular parameters of Biomphalaria alexandrina snails

The results showed that survival rates of Biomphalaria alexandrina snails, reproductive potential and hatchability of eggs were evaluated post exposure to Basudin, Selecron and Colchicine. As well, DNA and RNA changes in the cells of ovotestis–digestive gland complex of treated snails were estimated. The current molluscicide Bayluscide was used as a reference compound.The pesticide Selecron proved to be more toxic to B. alexandrina snails than Basudin and Colchicine. Juvenile snails were dead post 3 weeks of exposure to the sublethal concentration LC0 of either Selecron or Basudin, while 26.75% of snails still alive at Bayluscide treatment. In addition, exposure of adult snails to LC0 of Selecron for 24 h/week for 4 weeks markedly reduced their reproductive rate (R0) by 89.9%. Moreover, snails’ eggs failed to hatch post 24 h of exposure to LC90 of either Selecron, Basudin or Bayluscide. Electrophoretic analysis indicated a decrease in the molecular weight of intact DNA in the ovotestis–digestive gland complex of snails treated with 250 ppm of Colchicine and LC25 of Selecron, as it scored 1.2 and 76 bp, respectively, compared to 166.46 bp for control group, while the vice versa was recorded for RNA intensity. It was concluded that the tested pesticides have deleterious effects on snails’ reproductive rate, their eggs and the intensities of DNA and RNA in their ovotestis–digestive gland complex. Therefore, it is expected that reaching of such pesticides to snails’ habitats in water courses during plant pests control could minimize the population density of the snails intermediate hosts of schistosomiasis, hence probably interrupt and reduce the transmission of this parasite.

Electrophoretic patterns of intact and damaged DNA in ovotestis–digestive gland complex of B. alexandrina snails exposed for 24 h weekly for four successive weeks to: (A) Basudin, (B) Selecron, (C) Bayluscide and (D) Colchicine. Where: Cn = control, lane 1 = LC0, lane 2 = LC10 and lane 3 = LC25 of Basudin, Selecron or Bayluscide, lanes 4 and 5 = 100 and 250 ppm of Colchicine, respectively.Figure optionsDownload as PowerPoint slideHighlights
► Biomphalaria alexandrina snails from laboratory bred colony in Medical Malacology Department.
► Survival rates of snails were reduced post their exposure LC25 of Basudin, Selecron, Bayluscide and Colchicine.
► Reproductive rate for snails were reduced post their exposed to the tested compounds.
► The hatchability of B. alexandrina eggs was diminished after exposure to the tested compounds.
► The damaged DNA and RNA in the cells of ovotestis–digestive gland of snails treated.