Aedes aegypti is an important vector for Dengue and Dengue hemorrhagic fever. Considering its medical importance and its relevance as a model system, this study was undertaken to evaluate the impact of different doses of gamma radiation for three generations of A. aegypti. Two to three days old virgin males of A. aegypti were irradiated with 15 doses of gamma radiation, ranging from 1 to 50 Gy and were immediately mass mated with the same aged virgin females. Observations were made for changes on their life history traits, particularly fecundity, hatchability, adult emergence, sex ratio and longevity, for three generations. Adult males exposed 30, 35, 40, 45 and 50 Gy doses showed a significant decrease in fecundity in F0 generations. While hatchability was observed to have decreased with increasing radiation doses from 3 Gy onwards in the F1 generation, samples irradiated with 30, 35, 40, 45 and 50 Gy maintained significant decline in hatchability in their succeeding generations, F2 and F3 also. Similarly, a decline was observed in adult emergence from 3 Gy onwards in all three generations. A male favoring sex ratio distortion was observed at the doses of 35, 40, 45 and 50 Gy in all three generations. Following exposure to 4 Gy, parental males and the resultant progeny showed increased longevity by 10.56 and 8.66 days respectively. Similarly, the F1 generations of samples irradiated with 30, 35 and 40 Gy exhibited an increase in longevity by 7.16, 7.44 and 6.64 days respectively. Dose response curve for fertility among the three generations was drawn and presented. The effect of radiological exposure on the life history traits of A. aegypti varies with dose for the three generations studied. These results have potential implications in mutational studies and risk assessment and also contribute to a better understanding towards employment of the sterile insect technique in A. aegypti, plausibly paving the way to an effective mosquito genetic control program.

The study was undertaken to evaluate gamma radiation-induced DNA damage in Aedes aegypti. The comet assay was employed to demonstrate the extent of DNA damage produced in adult male A. aegypti exposed to seven different doses of gamma radiation, ranging from 1 Gy to 50 Gy. DNA damage was measured as the percentage of comet tail DNA. A significant linear increase in DNA damage was observed in all samples; the extent of damage being proportional to the dose of gamma radiation the organism received, except in those treated with 1 Gy. The highest amount of DNA damage was noticed at 1 h postirradiation, which decreased gradually with time, that is, at 3, 6 and 12 h postirradiation. This may indicate repair of the damaged DNA and/or loss of heavily damaged cells as the postirradiation time increased. The comet assay serves as a sensitive and rapid technique to detect gamma radiation-induced DNA damage in A. aegypti. This could be used as a potential biomarker for environmental risk assessment.

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ABSTRACT:The chemical mutagen Diethylsulphate (DES) was treated to the mulberry silkworm, NB 4 D 2 breed at the age, fifth instar fifth day with different concentrations (8mM and 10mM) by injection and spray methods. The F 1 progeny was obtained from DES treated and control sets by selfing the moths. The quantitative analysis of haemolymph proteins revealed that 8mM injection set exhibit higher levels when compared with control and treated sets. The quantitative analysis also clearly indicate the variations in the number as well as intensity of the protein bands. @JASEMThe various aspects of protein metabolism including quantitative changes in haemolymph protein synthesis and metabolic activity of specific enzymes have attracted the interest of many insect biochemists. The available results from these biochemical studies indicate that protein metabolism is of considerable importance in characterizing different stages of insect development (Chen, 1966). Haemolymph proteins play an important role in insects for transport functions, as well as for their enzyme action. The synthesis and utilization of haemolymph proteins are controlled by genetic and hormonal factors (Hurliman and Chen, 1974). Although our knowledge of insect haemolymph proteins has greatly advanced during the last decade, still only the origin and function of few major proteins are known (Riddiford and Law 1983). There is general agreement that the fat body is a main source of haemolymph proteins (Dean et al., 1985 and Keeley, 1985) and others may come from haemocytes (Hughes and Price, 1976, Katagiri, 1977). Extensive studies of blood during development in Hyalophora cecropia and Samia Cynthia have been made using starch gel electrophoresis (Lauffer, 1960). It has been reported that blood proteins fluctuate during the development of Bombyx mori (Heller, 1927). The protein concentration was found to increase seven folds during the larval life of Bombyx mori (Bito, 1927 and Florkin, 1936). Recently number of researchers worked on silkworm protein variations, qualitatively and qualitatively occurs during mutagens treatment in general and chemical mutagens in particular during larval development (Mahesh, 1997; Bashamohideen and Ameen, 1998; Mahesha et al., 2000). However studies on chemical mutagens particularly effect on haemolymph is meagre. Hence, the present investigation was attempted to study the effect of chemical mutagen on haemolymph proteins of silkworm, Bombyx mori L. during larval fifth instar stage. MATERIALS AND METHODSThe silkworm race, NB 4 D 2 a bi-voltine breed and chemical mutagen DES (Diethyl sulphate) were used for the study. The eggs were procured from private agency and incubated at temperature 25±1 o C and 70-80% relative humidity in an incubator. Block box was carried out on 8 th day to achieve uniformity in hatching. The hatched larvae were reared in environmental chamber by providing with suitable quality mulberry leaves of Morus alba (variety V 1 ). The rearing was conducted by following the method discribed by Raja Ram...

ABSTRACT:The silkworms of NB 4 D 2 variety were treated with chemical mutagen Diethyl sulphate (DES). The larvae were subjected to two methods of treatments i.e., oral administration of the chemical mutagen and by injection of 8mM and 10mM concentrations of chemical mutagen through body wall. The lethal effect of the mutagen was studied in the subsequent generation. The effect was drastic on structure & morphology of the meiotic chromosomes. Many structural, physiological and numerical aberrations were observed and documented. Certain numerical changes such as induction of polyploids were attributed to the improvements observed in the expression of commercial characters in the silkworm. @ JASEM