ABSTRACT
Esterase isozymic variations were documented in the haemolymph of developed multivoltine and bivoltine silkworm breeds during unfavorable seed crop seasons of May – September using α- and β- napthylacetate separately to identify specific and nonspecific esterase having thermotolerant potentiality. Variations existed in the isozyme pattern with three bands (Est-2, 3 and 4) in pure Nistari race and other developed multivoltine and bivoltine breeds. Est-2 and Est-3 were non-specific esterases as they were observed when both α- and β-napthylacetate was used as substrates separately. Est- 4 band was observed only with α-napthylacetate as substrate and was therefore confirmed to be specific α-esterase band in the haemolymph of silkworm, Bombyx mori L. Zymograms showed that the non-specific esterase band (Est-3) with Rf of 0.43 and specific α-esterase band (Est-4) with Rf of 0.32 predominately withstood a temperature of 70 ± 2oC for a duration of 10 min and were confirmed as thermostable esterases in haemolymph of silkworm, Bombyx mori L. This also categorized the presence of thermostable esterases in developed multivoltine and bivoltine breeds of silkworm, even though the qualitative activity was more in the former than the latter. The qualitative presence of thermostable esterases and their activity could be adopted as an indicative biochemical marker in relation to thermotolerance in silkworm.
ABSTRACT
The present study investigated the effect of increasing temperature stress on the thermotolerance of B. mori crossbreed PM x CSR2 and tissue specific differential expression of heat shock proteins at IVth and Vth instars. The larvae reared at 25 ± 1oC and 70 ± 5% relative humidity were treated as control. Larvae were subjected to heat shock temperatures of 34, 38 and 42oC for 3 hr followed by 3 hr recovery. Expression of Heat shock protein 72 were analyzed by SDS-PAGE and confirmed by western blotting analysis. The impact of heat shock on commercial traits of cocoons was analyzed by following different strategies in terms of acquired thermotolerance over control. Resistance to heat shock was increased as larval development proceeds and increased thermotolerance is achieved with the induction of Heat shock protein 72 in the Vth instar larval haemolymph. Relative influence of heat shock temperatures on commercial traits corresponding to the generation of heat shock protein 72 was significantly improved over control. In PM x CSR2, cocoon and shell weight significantly increased to 9.90 and 11.90% over control respectively.
ABSTRACT
Sprague Dawley strain of male rats weighing 200 ± 10.0 g, were exposed intramuscularly to non-lethal dose of mercury for short acute duration of 24 and 48 hr. Mercury treatment increased thio-barbituric acid reactive substance (TBARS) and conjugated diene (CD) content with increase in duration when compared with control. This reflects possible increase in lipid peroxidation, revealing that sufficient intoxication was generated by non-lethal dose of mercury. Furthermore, mercury treatment decreased tissue glutathione (GSH) content to 2.07 and 1.49 3g GSH mg protein-1 with concomitant decrease in glutathione-S-transferase (GST) activity by 26.06 and 36.40% after 24 and 48hr of exposure respectively. The elevations of aspartate transaminase (AST) and alanine transaminase (ALT) levels measured exhibited increase of 287.5 and 214.5% after 48 hr of exposure respectively which were found to be highly significant compared with control. Western blot analysis indicated upregulation of caspase-9 and upsurge in effector caspase-3 activity leading to apoptosis. The concluded findings of the present investigation suggests possible role of early mercury exposure in inducing oxidative stress mediated apoptosis in mammalian model systems as an indicator component of environmental toxicology.
ABSTRACT
Labeo rohita fingerlings were exposed to zinc metal toxicity (5 and 10 ppm) for duration of 5 and 15 days. The histological changes were studied in brain and liver of the treated fish. The brain tissues showed enlarged pyramidal cells with extensive vacoulation while severe necrosis, haemorrhage and degeneration of hepatocytes were witnessed in the liver tissues.