Efficacy of Bacillus thuringiensis var. Kurstaki in the control of two mosquito species (Anopheles stephensi and Culex quinquefasciatus).

Bioinsecticide Bacillus thuringiensis var. kurstaki (Btk) was used for controlling the mosquito species (Anopheles stephensi and Culex quinquefasciatus) which gave a significant (p<0.05) mortality in both species. The higher concentration of Btk was highly effective compared to the control ones. The controlling effect was dose and time dependent. Among the studied mosquitoes the C. quinquefasciatus (LC50 0.154%) was more susceptible than A. stephensi (LC50 0.372%) towards the bioinsecticide Btk.

Changes in the level of transaminases in Indian major carp, Labeo rohita exposed to sublethal concentration of tannery and distillery effluents.

The activity of alanine aminotransferase (ALAT) and aspartate aminotransferase (AAT) of different tissues of fingerlings of Labeo rohita under the influence of two effluents has been studied. The alanine aminotransferase activity was increased over the control in different exposed periods of tannery and distillery effluent treatments. The alanine aminotransferase in the liver showed increased activity at different periods than that of the muscle, kidney, gill and brain (p < 0.001) (60.09%) over the control during the 40 days exposure in both the effluents treatments. The increased activity of alanine aminotransferase was highly significant (p > 0.001) in all the tissue in tannery and distillery effluents treatments. Similarly aspartate aminotransferase activity was increased over the control in all the treated tissues from 10 to 40 days exposure. But this increase, was not significant in the muscle tissue in distillery and tannery treatements after 10 days exposure. From 10 to 40 days, the activity was increased but a maxmum elevation was observed during 40 days, where the elevation was more in the liver, which was followed by muscle, kidney, gill, brain (brain < gill < kidney < muscle < liver).

Gill lesions in the major carp, Labeo rohita exposed to lethal and sublethal concentrations of tannery effluent.

The major carp, Labeo rohita were exposed to (0.873%) lethal and sublethal (0.073%) concentrations of tannery effluent for 24h and 40 days respectively under static bioassay condition. The surface architecture of gill revealed severe damages such as : fusion and clumping in the middle and distal parts of the primary lamellae, swelling and deterioration of the cells. The interlamellar space was filled either with hyperplastic epithelial or mucous cells. Secondary lamellae lost their identity and appeared finger like in structure in the lethal concentration and necrosis was observed in the primary and secondary epithelium. Swelling of primary and secondary epithelial cells was evident in sublethal concentration.

Toxic effects of copper and zinc mixtures on some haematological and biochemical parameters in common carp, Cyprinus carpio (Linn).

The effect of heavy metals and mixture were studied on some haematological and biochemical parameters in fish, Cyprinus carpio at sublethal level over the period of 30 days. Heavy metal significantly decreased total RBC count, haemogoblin, heamatocrit (Hct) (except copper after 10 days exposure). The WBC count was increased significantly in all the treated fish. The MCH, MCHC, MVC were increased depending upon the exposure period; declined PVC was noticed at 1% level of significance after 30 days on all the treated fish. Serum level of chloride and calcium content were increased where as serum glucose, cholesterol and total serum protein were decreased significantly. The alteration in haematological and biochemical parameters shows more toxic in mixture after 30 days, showed more than 'addition action' of the individual toxicant.