Jawaharlal Nehru University

About: Jawaharlal Nehru University is a education organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Politics. The organization has 6082 authors who have published 13455 publications receiving 245407 citations. The organization is also known as: JNU.

Assessing aquaglyceroporin gene status and expression profile in antimony-susceptible and -resistant clinical isolates of Leishmania donovani from India

Abstract: Received 8 September 2009; returned 9 October 2009; revised 25 November 2009; accepted 26 November 2009 Objectives: Clinical resistance to pentavalent antimonials results from an interplay between uptake, efflux and sequestration in Leishmania. Aquaglyceroporins (AQPs) have been shown to facilitate uptake of trivalent metalloids. Down-regulation of AQP1 in Leishmania results in resistance to trivalent antimony, whereas overexpression of AQP1 in drug-resistant parasites can reverse the resistance. The present work investigates the role of AQP1 in monitoring antimonial resistance in Indian leishmaniasis. Methods and results: Susceptibility to trivalent antimony as determined in vitro with intracellular amastigotes from both visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL) patients correlated well with the clinical response. Higher accumulation of trivalent antimony (SbIII) was observed in all susceptible isolates compared with resistant isolates. Reduced accumulation of SbIII correlated, with a few exceptions, with down-regulation of AQP1 RNA as determined by real-time PCR. Cloning and sequencing of the AQP1 gene from both VL and PKDL isolates showed sequence variation in four of the clinical isolates. None of the isolates had an alteration of Glu152 and Arg230, which have been previously shown to affect metalloid transport. Transfection of the AQP1 gene in a sodium antimony gluconate-resistant field isolate conferred susceptibility to the resistant isolate. Conclusions: Our studies indicate genetic variation in VL and PKDL isolates. Down-regulation of AQP1 correlates well with clinical drug resistance in a majority of Indian VL and PKDL isolates. AQP1 gene expression at both the genetic and transcriptional level showed positive correlation with SbIII accumulation, with some exceptions.

Production and characterization of xylanase from Bacillus thermoalkalophilus grown on agricultural wastes

Abstract: Bacillus thermoalkalophilus isolated from termite-infested mound soils of the semi-arid zones of India had the ability to produce good amounts of xylanase(s) from cheap agricultural wastes. Of the two hemicellulosic substrates tested, bagasse was found to be the better inducer for xylanase production. Alkali treatment of bagasse and rice husk had varied effects on enzyme production. The enzyme preparation had activity optima at 60° C and 70° C and a half-life of 60 min at 65° C. The enzyme was stable for 24 h over a pH range of 4.0–6.0, while maximum activity was observed at pH 6.0–7.0. Enzyme production and activity were inhibited by the end-product of xylan hydrolysis, xylose.