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 & Candida albicans. The organization has 6082 authors who have published 13455 publications receiving 245407 citations. The organization is also known as: JNU.

Growth and ecological impacts of traditional agroforestry tree species in Central Himalaya, India

Abstract: A number of multipurpose tree species are conserved as scattered trees in settled farms on terraced slopes by the traditional farmers in Central Himalaya, India. Knowledge on growth rates and ecological impacts of these tree species is limited. Ten locally valued multipurpose tree species, viz., Albizzia lebbek, Alnus nepalensis, Boehmeria rugulosa, Celtis australis, Dalbergia sissoo, Ficus glomerata, Grewia optiva, Prunus cerasoides, Pyrus pashia and Sapium sebiferum, were established as mixed plantations at a degraded community forest land site and an abandoned agricultural land site in a village at 1200 m altitude in District Chamoli, India. At the abandoned agricultural land site, annual food crops were grown, along with planted trees, providing supplemental irrigation and organic manure following traditional farming practices. Survival, height, stem circumference, crown depth and width, number of branches, above-ground biomass and soil physico-chemical characteristics were monitored up to five years of plantation growth. Above-ground tree biomass accumulation at the abandoned agricultural land site was 3.9 t ha−1 yr−1 compared with 1.1 t ha−1 yr−1at the degraded forest land site. B. rugulosa, C. australis, F. glomerata, G. optiva, P. cerasoides and S. sebiferum showed more prominent differences in growth at the two sites compared with A. lebbek, A. nepalensis, D. sissoo and P. pashia. A. nepalensis and D. sissoo showed best growth performance at both the sites. A significant improvement in soil physico-chemical characteristics was observed after five years at both of the sites. Carbon sequestration in soil was higher than that in bole biomass.

Simulation of mesoscale features associated with intense western disturbances over western Himalayas

Abstract: North India is comprised, in parts, of complex Himalayan mountain ranges having different altitudes and orientations all along this region. Due to the highly variable altitude and orientation of orographic barriers the prevailing weather conditions over the region are complex. The winter season over this region is frequented by eastward-moving low pressure synoptic weather systems called Western Disturbances (WDs). Advance information of these WDs are important for organizations where men and machines are employed to operate in the open, for example, for defence purpose, agriculture, tourism and transport. Future projection of meteorological variables is important during the winter in assessment of cold wave conditions, avalanche release and a critical human comfort index. Therefore, a non-hydrostatic version of the Penn State University/National Center for Atmospheric Research, US, (PSU/NCAR) mesoscale model is used to simulate the characteristic features of the Western Disturbances (WDs) occurring over the Indian region during a winter season. For this study, four cases of active WDs are selected. The model is integrated with 60 km horizontal resolution to simulate the WD features. The model simulations with 60 km horizontal resolution are compared with the National Center for Environmental Prediction/National Center for Atmospheric Research, US, (NCEP/NCAR) reanalyses. It is seen that in all the cases the rate of movement of the system is, in general, a little slower in the simulations. Examining the differences between the predicted and analysed zonal component of the wind reveal that the model simulated zonal winds are generally weaker/under-estimated in the location of the upper trough at 500 hPa or aloft and even in the position of the WDs at lower levels. These results suggest that the model has a systematic easterly bias, though the magnitude is small. In other words the advection simulated in the model is not strong enough to advect the system with the observed speed. Copyright  2009 Royal Meteorological Society

Leishmania donovani depletes labile iron pool to exploit iron uptake capacity of macrophage for its intracellular growth

Abstract: Intracellular pathogens employ several strategies for iron acquisition from host macrophages for survival and growth, whereas macrophage resists infection by actively sequestering iron. Here, we show that instead of allowing macrophage to sequester iron, protozoan parasite Leishmania donovani (LD) uses a novel strategy to manipulate iron uptake mechanisms of the host and utilizes the taken up iron for its intracellular growth. To do so, intracellular LD directly scavenges iron from labile iron pool of macrophages. Depleted labile iron pool activates iron sensors iron-regulatory proteins IRP1 and IRP2. IRPs then bind to iron-responsive elements present in the 3′ UTR of iron uptake gene transferrin receptor 1 by a post-transcriptional mRNA stability mechanism. Increased iron-responsive element–IRP interaction and transferrin receptor 1 expressions in spleen-derived macrophages from LD-infected mice confirm that LD employs similar mechanism to acquire iron during infection into mammalian hosts. Increased intracellular LD growth by holo-transferrin supplementation and inhibited growth by iron chelator treatment confirm the significance of this modulated iron uptake pathway of host in favour of the parasite.

Identification of novel target sites and an inhibitor of the dengue virus E protein

Abstract: Dengue and related flaviviruses represent a significant global health threat. The envelope glycoprotein E mediates virus attachment to a host cell and the subsequent fusion of viral and host cell membranes. The fusion process is driven by conformational changes in the E protein and is an essential step in the virus life cycle. In this study, we analyzed the pre-fusion and post-fusion structures of the dengue virus E protein to identify potential novel sites that could bind small molecules, which could interfere with the conformational transitions that mediate the fusion process. We used an in silico virtual screening approach combining three different docking algorithms (DOCK, GOLD and FlexX) to identify compounds that are likely to bind to these sites. Seven structurally diverse molecules were selected to test experimentally for inhibition of dengue virus propagation. The best compound showed an IC(50) in the micromolar range against dengue virus type 2.