A reliable assessment of the viability of schistosome eggs trapped in host tissues is difficult. The use of a coupling azo dye method for the detection of alkaline phosphatase (A1P) in Schistosoma mansoni ova was found to be a specific and sensitive method for differentiating between viable and dead eggs, and can be used in both immature and mature eggs. In fully developed miracidia within an egg, A1P activity was demonstrated in germ cells and in the sensory endings of the neural cells. The embryonating miracidia displayed A1P activity on the body surface and in von Lichienberg’s envelope. The alkaline phosphatase test for egg viability shows increased sensitivity when compared with the more conventional Oogram and Hatching tests.
The low chlorophyll b mutant of high yield rice had a lower light-harvesting complex 2 content than the wild type. The stability of oxygen evolution side of photosystem 2 was only slightly lower. A lower photon absorption rate and a stronger xanthophyll cycle capacity of this mutant led to a higher endurance to strong irradiance and a lower photoinhibition as compared with the wild type rice. and Xinbin Dai ... [et al.].
The toxicity of cadmium and zinc at concentrations ranging from 0.1 to 100 µg/l was investigated against the activity of Diplostomum spathaceum (Rudolphi, 1819) cercariae. Over a 24 h exposure period a significant reduction in cercarial activity occurred in solutions of cadmium, zinc, and a mixture of cadmium and zinc at all concentrations. Reduced cercarial activity also occurred in all toxicant solutions compared with controls after only 6 h exposure indicating that cercariae were vulnerable during the period of maximum cercarial infectivity (0-5 h). The mechanisms of metal toxicity and their importance to parasite transmission are discussed.