Impact of temperature on heat shock protein expression of Bombyx mori cross-breed and effect on commercial traits.

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.

Zinc induced histological changes in brain and liver of Labeo rohita (Ham.).

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.

A preliminary report on effect of pulsed magnetic fields on fresh water fish (Labeo rohita) chromosomes.

Marine-life scientists around the world are already carrying out investigative trials to obtain higher yields under in-captive breeding conditions, on both edible varieties and ornamental fishes with optimal inputs. However, for such trials to succeed there is a need for genetic improvement. The idea that fish production can be enhanced by genetic manipulation is gaining acceptance, as there is a strong possibility that qualitative improvement of economically important traits can be achieved by identifying and utilizing more effective genotypes. In the present communication a tentative plan for genetic manipulation of fresh water fish using controlled, pulsed magnetic fields, is being discussed. Chromosome preparations of Labeo rohita were made using Colchicine-Methanol-Acetic acid air drying technique, using tissue from gills. The fish were exposed to Pulsed Magnetic Field (PMF)with intensity 0.2 Gauss, pulsing at 50 Hz frequency (sine wave) for 6 hours / day for a total period of 30 days inside specially designed magnetic field enclosures. The karyological investigations revealed no distinct difference between "test" and "control" groups.

Impact of cadmium on food utilization of the Indian major carp, Catla catla (Ham).

Catla catla, under the sublethal stress of cadmium exhibited depletion in food utilization parameters and it was concentration dependent. Heavy metal intoxication was found to exhibit reduction in biomass.