Showing papers on "Biomphalaria alexandrina published in 1982"

The effect of temperature, darkness, starvation and various food types on growth, survival and reproduction of Helisoma duryi, Biomphalaria alexandrina and Bulinus truncatus (Gastropoda: Planorbidae)

Abstract: Helisoma duryi has been proposed as a biological control agent in schistosomiasis due to its superiority in laboratory competition experiments with various species of the intermediate host snails. Therefore it was considered important to evaluate the response of this snail species and the intermediate host species, Biomphalaria alexandrina and Bulinus truncatus, to various physical, chemical and biological factors under laboratory conditions in order to obtain information on the similarities in the ecological niches of these species. The factors considered in the present paper are: temperature, darkness, starvation and food. All three species had optimal growth and egg laying at 26–28 °C. Only H. duryi survived for a longer period at 33°C and it was capable of starting egg laying at this temperature although the onset was delayed. However, low temperature (18°C) caused a relatively larger decrease in egg laying of H. duryi than in the other two species. Growth and egg laying was reduced for H. duryi and B. truncatus kept under darkness and B. alexandrina could not tolerate maintenance under darkness. A few days of starvation of juvenile snails had no effect on later growth and egg laying capacity of the survivors, although mortality in B. truncatus was increased. B. alexandrina had a lower tolerance to starvation than the other two species. Egg laying of snails fed only one of the three laboratory food types decreased for all three species in the order: Vov-vov (dog food in dry pellets), Tetramin (fish food) and lettuce. Combinations of lettuce and one or more proteinaceous food types gave optimal growth and egg laying for all three species.

Comparative effects of schistosome infection and starvation on the respiratory transport chain of the snails Biomphalaria alexandrina and Bulinus truncatus

Abstract: 1. 1. The activity of succinate oxidase, NADH oxidase, Succinate—methylene blue reductases and Cytochrome oxidasa was determined. 2. 2. The rate of oxidation of these enzymes was higher in B. truncatus then B. alexandrina . However, the mitochondrial system of B. truncatus is more sensitive to starvation and Schistosome infection conditions. 3. 3. Both starvation and schistosome infection inhibit the oxidation of these enzymes which was more pronounced in case of starvation. 4. 4. Addition of Amytal, glutamate α-keto-glutarate, ATP and ADP to mitochondrial preparation reversed the inhibition effects caused by schistosome infection and did not reduce the inhibitory effects of starvation. 5. 5. It is suggested that the reduction in oxygen consumption by mitochondria prepared from infected snails is attributed to accumulation of oxaloacetate, and that from starved snails attributed to other mechanisms in which accumulation of oxaloacetate is not involved.

The molluscicidal properties of the crude saponins in Agave angustifolia «Marginata» Agave celsii and Yucca filamentosa «Variegata»

Abstract: L'etude comparative de la sensibilite de Biomphalaria alexandrina et Bulinus truncatus a l'action de saponines dans des extraits aqueux de Agave angustifolia, A. celsii et Yucca filamentosa est determinee. L'action de quelques facteurs de l'environnement sur l'activite molluscicide de ces saponines est recherchee

The molluscicidal activity of Euphorbiaceae euphorbia Peplus-3

Abstract: L'activite molluscicide de differents extraits d'Euphorbia peplus contre Biomphalaria alexandrina et Bulisus truncatus est rapportee. L'action des facteurs de l'environnement sur la capacite molluscicide du methanol et du chloroform de E.p. est recherche. Les composants actifs de la plante sont isoles et identifies