Arun K. Ray

Alterations in air-sac and skeleton of triploid Heteropneustes fossilis

Thu, 01 Jan 2004 00:00:00 GMT

Alterations in air-sac and skeleton of triploid Heteropneustes fossilis Tiwary, B. K.; Ray, Arun Kumar Triploid stinging catfish Heteropneustes fossilis, when produced by cold shock, showed abnormalities in their air-sacs and skeletons. DOI: 10.1046/j.1095-8649.2003.00287.x

Putative L-triiodothyronine receptors in the liver nuclei of mature tropical toad, Bufo melanostictus

Thu, 01 Jan 2004 00:00:00 GMT

Putative L-triiodothyronine receptors in the liver nuclei of mature tropical toad, Bufo melanostictus Sarkar, P. K.; Dey, S. S.; Koley, B.; Koley, J.; Ray, Arun Kumar Thyroid hormones exert a major role in growth and differentiation of almost all types of tissues in animals, particularly in amphibian metamorphosis, through its specific nuclear receptor activation followed by gene expression. However, its function in mature tropical amphibians is less studied. The present study revealed the existence of a single class of specific nuclear receptor(s) in the liver nuclei of mature tropical toad, Bufo melanostictus, with a dissociation constant of (3.7 +/- 0.9) x 10(-10) molar and maximum binding capacity of 0.074 +/- 0.013 pmol/mg DNA. The percentage of relative binding affinities for the specific nuclear L-T3 binding site in the liver nuclei of toad were L-triiodothyronine (L-T3) > triiodothyroacetic acid (TRIAC) > L-thyroxine (L-T4) = tetraiodothyroacetic acid (TETRAC) > 3,3',5'-triiodothyronine (r-T3) > Diiodothyrtonine (L-T2) (100 > 75 > 19.4 = 19.4 > 3.7 > 0.39) and the relative ED50 values (in nanomolar) were 0.33 < 0.44 < 1.7 = 1.7 < 9 < 83.

Stimulation of AChE activity in relation to changes in electron microscopic structure of adult rat cerebrocortical synaptosomes pretreated with 3-5-3 '-triiodo-L-thyronine

Wed, 06 Aug 2003 00:00:00 GMT

Stimulation of AChE activity in relation to changes in electron microscopic structure of adult rat cerebrocortical synaptosomes pretreated with 3-5-3 '-triiodo-L-thyronine Chakrabarti, N.; Ray, Arun Kumar Triiodothyronine (T-3) stimulated AChE activity in depolarization-induced intact synaptosomes (isolated from adult rat cerebral cortex) suspended in calcium-supplemented choline chloride buffer in a time-dependent manner maximally 45-60 s after T-3 administration and in a dose-dependent manner with an optimum at 10-100 nM. T-3 (100 nM) had no such effects on AChE activity in synaptosomes at non-depolarized conditions. There was no direct effect of T-3 on AChE activity of lysed synaptosomal suspension in the physiological range (nM) of T-3. The experiments suggest that T-3 might have a role in the calcium-dependent release/co-release of acetylcholine from intact synaptosomes concomitant with the acceleration of choline uptake mechanisms that has been reported to accompany elevation of AChE activity. Additionally, electron microscopic structures showed condensation of the cytosolic content with increase in electron density, formation of intrasynaptosomal coarse vesicles and appearance of vesicular fusion like structures (meandering) at the periphery in depolarization-induced T-3-treated (60 s) intact synaptosomes, indicating the occurrence of the release of neurotransmitters. The present investigation indicates a definite role of T-3 on Ca2+-dependent cholinergic neurotransmission. DOI: 10.1097/01.wnr.0000080102.90506.40

The biology of triploid fish

Wed, 01 Dec 2004 00:00:00 GMT

The biology of triploid fish Tiwary, B. K.; Kirubagaran, R.; Ray, Arun Kumar This review deals with major areas of triploidy research in fish. It includes not only methods for induction and detection of triploidy but also the impact of triploidy on morphology, anatomy, growth, haematology, energetics, behaviour, endocrinology and gonads in various species of fish, studied so far. The future prospects of research on triploid fish are discussed inviting researchers with diverse areas of interest in fish biology. DOI: 10.1007/s11160-004-8361-8