http://nopr.niscair.res.in/handle/123456789/4395 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/5528 Title: Abnormal anther development and high sporopollenin synthesis in benzotriazole treated male sterile <i style="">Helianthus</i> <i style="">annuus</i> L. <br/> <br/>Authors: Tripathi, S M; Singh, K P <br/> <br/>Abstract: Foliar application of 1.5% benzotriazole induced 100% pollen sterility in <i style="">H. annuus</i>. Pollen abortion in treated plants was mainly associated with abnormal behaviour of tapetum. A limited number of anther locule showed early degeneration of tapetum followed by disintegration of sporogenous tissues. On the other hand, some locules showed normal development of tapetum at initial stages. However, this tapetum exhibited degenerated and non-functional cell organelles. In both these situations tapetum failed to provide proper nourishment to developing microspores. The ultrastructure of both tapetum and microspores is different from that of control material with irregularities of exine deposition, endopolyploidy of tapetal nuclei and an alteration of organelle composition being correlated with sterility. Pollen grains thus developed were devoid of nucleus and cell organelles and were complete sterile. <br/> <br/>Page(s): 71-78 Sat, 29 Dec 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4661 Title: Effect of dietary iron overload in rat brain: Oxidative stress, neurotransmitter level and serum metal ion in relation to neurodegenerative disorders <br/> <br/>Authors: Elseweidy, Mohamed M; El-Baky, Atef E Abd <br/> <br/>Abstract: Excess iron causes cell injury by reacting with superoxide anions (O₂) and hydrogen peroxide (H₂O₂) and producing hydroxyl radical (OH) and reactive oxygen species (ROS). In the present study, albino rats were fed with biscuits enriched with ferrous sulphate (0.3% w/w) for 10 weeks to have overload iron conditions and observed a significant decrease in serum chromium, brain serotonin and dopamine, while iron and zinc increased significantly in serum. Increasing iron level might be responsible for accelerated dopamine oxidation with subsequent quinone formation. <br/> <br/>Page(s): 855-858 Fri, 28 Nov 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4660 Title: Na⁺ K⁺-ATPase activity in response to exogenous dehydroepiandrosterone administration in aging rat brain <br/> <br/>Authors: Taha, Asia; Mishra, Monika; Baquer, N Z; Sharma, Deepak <br/> <br/>Abstract: Influence of exogenously administered dehydroepiand-rosterone (DHEA) on the activity of Na⁺K⁺ATPase was investigated in synaptosomal fraction from cerebral cortex, cerebellum, hippocampus and medulla regions of brain of 12 and 22 months old rats. DHEA was administered daily at the dose of 30 mg/kg/body wt, intraperitonially (ip) in both the age groups of rats for 1 month. Results showed that Na⁺K⁺ATPase activity, increased in DHEA treated rats in both the age groups. In terms of per cent increase, 22 months old animals showed significant increase in Na⁺K⁺ATPase activity in the synaptosomal fraction of all the four brain regions than in 12 months old DHEA-treated rats. This showed that exogenous DHEA modulated the activity of Na⁺K⁺ATPase and also protected the age-related loss of membrane integrity and functions. It was concluded that exogenous DHEA might be beneficial in terms of neuroprotection against age-related loss of Na⁺ K⁺ ATPase mediated brain functions like learning and memory. <br/> <br/>Page(s): 852-854 Fri, 28 Nov 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4659 Title: Regulation of urease in <i style="">Bradyrhizobium</i> colonizing green gram (<i style="">Vigna radiata</i> (L.) Wilczek) <br/> <br/>Authors: Sen, Devyani; Appunu, C; Singh, R K <br/> <br/>Abstract: In the present study attempts have been made to characterize urease expression in slow growing <i style="">Bradyrhizobium</i> strains TAL442 and MO5 which are endosymbionts of green gram (<i style="">Vigna radiata</i> (L.)Wilczek). It was found that urease activity in vegetative cells of both the strains was inducible unlike their fast growing counterparts. Mode of regulation in TAL442 was governed by presence of ammonia. Urease expression was also detectable in bacteroids of both the strains which was not influenced by presence of external nickel chloride in high concentration, a situation detrimental to the vegetative cells. <br/> <br/>Page(s): 846-851 Fri, 28 Nov 2008 22:58:59 GMT