Habitat occupancy of sloth bear Melursus ursinus in Chitwan National Park,Nepal

Mammals have experienced a massive decline in their populations and geographic ranges worldwide. The sloth bear, Melursus ursinus (Shaw, 1791), is one of many species facing conservation threats. Despite being endangered in Nepal, decades of inattention to the situation have hindered their conservation and management. We assessed the distribution and patterns of habitat use by sloth bears in Chitwan National Park (CNP), Nepal. We conducted sign surveys from March to June, 2020, in 4 × 4 km grids (n = 45). We collected detection/non‐detection data along a 4‐km trail that was divided into 20 continuous segments of 200 m each. We obtained environmental, ecological, and anthropogenic covariates to understand determinants of sloth bear habitat occupancy. The data were analyzed using the single‐species single‐season occupancy method, with a spatially correlated detection. Using repeated observations, these models accounted for the imperfect detectability of the species to provide robust estimates of habitat occupancy. The model‐averaged occupancy estimate for the sloth bear was 69% and the detection probability was 0.25. The probability of habitat occupancy by sloth bears increased with the presence of termites and fruits and in rugged, dry, open, undisturbed habitats. Our results indicate that the sloth bear is elusive, functionally unique, and widespread in CNP. Future conservation interventions and action plans aimed at sloth bear management must adequately consider their habitat requirements.     

Synthesis of 3-(1-alkyl/aminoalkyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-ones and their 2-methylene derivatives as potential spermicidal and microbicidal agents

A series of twenty two derivatives of 3-(1-alkyl/aminoalkyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-one and their 2-methylene derivatives were synthesized from naturally abundant cinchonine (I). Tartarate salts of these compounds were prepared and evaluated for spermicidal activity. The most active compounds (24, 27, 34, 36, and 38) showing potent spermicidal activity were further evaluated against different strains of Trichomonas vaginalis, for antimicrobial activity, in HeLa cell lines for cytotoxicity and against Lactobacillus jensenii for eco-safety. The tartarate of 3-(1-pentyl-3-vinyl-piperidin-4-yl)-1-(quinolin-4-yl)-propan-1-one (27) was found to be more active than N-9 in spermicidal activity.     

Development of nanostructured biomedical micro-drug testing device based on in situ cellular activity monitoring

Integration of micro and nanofabrication techniques with biotechnology has resulted in the development of in vitro analytical and diagnostic tools for biomedical applications. The focus of such technology has primarily been on therapeutic and sensing applications. The long-term integration of cells with inorganic materials provides the basis for novel sensing platforms. This paper describes the creation of, nanoporous, biocompatible, alumina membranes as a platform for incorporation into a cell based device targeted for in situ recording of cellular electrical activity variations due to the changes associated with the surrounding microenvironments more specifically due to the effect of therapeutic drugs. Studies described herein focus on the interaction of nanoporous alumina substrates embedded in silicon, patterned with cells of interest. The cells that have been used to develop the in vitro test platform are primary hippocampal neurons. Demonstrated here, is the fidelity of such a system in terms of determination of cell viability, proliferation, and functionality. The response of the cells to the "drug" molecules is electro-optically characterized in an in situ manner. The capability of such, micro fabricated nanoporous membranes as in vitro drug testing platforms, is first theoretically estimated using two dimensional finite element modeling of the diffusion of the molecules of interest through the nanoporous substrate using CFDRC. It is then experimentally established, using glucose and immunoglobulin G (IgG).     

Relationship between fluidity and L-alanine transport in a fatty acid auxotroph of Saccharomyces cerevisiae

The influence of the physical state of membrane on L-alanine uptake has been investigated in Saccharomyces cerevisiae KD115, an unsaturated fatty acid auxotrophic mutant. By monitoring the unsaturation index and steady state fluorescence polarization of 1,6 diphenyl hexatriene (DPH), it was observed that at mid log phase the membrane fluidity increased with an increase in the number of double bonds of supplemented fatty acid. Arrhenius plots of the velocities for L-alanine transport in cells grown on palmitoleate, oleate, linoleate and linolenate were biphasic and dependent on supplemented unsaturated fatty acid. Results illustrate a correlation between membrane fluidity and shift in transition points. Further, results confirm the role of fatty acyl milieu in regulation of transport activity of S. cerevisiae.     

RETRACTED ARTICLE: Monoaminergic and Nitriergic Modulation for Antidepressant-like Activity of Naringin in Unstressed and Acute Immobilization-Induced Stressed Mice

Neurochemical Research -     

Genomic instability and enhanced radiosensitivity in Hsp70.1- and Hsp70.3-deficient mice

Heat shock proteins (HSPs) are highly conserved among all organisms from prokaryotes to eukaryotes. In mice, the HSP genes Hsp70.1 and Hsp70.3 are induced by both endogenous and exogenous stressors, such as heat and toxicants. In order to determine whether such proteins specifically influence genomic instability, mice deficient for Hsp70.1 and Hsp70.3 (Hsp70.1/3(-/-) mice) were generated by gene targeting. Mouse embryonic fibroblasts (MEFs) prepared from Hsp70.1/3(-/-) mice did not synthesize Hsp70.1 or Hsp70.3 after heat-induced stress. While the Hsp70.1/3(-/-) mutant mice were fertile, their cells displayed genomic instability that was enhanced by heat treatment. Cells from Hsp70.1/3(-/-) mice also display a higher frequency of chromosome end-to-end associations than do control Hsp70.1/3(+/+) cells. To determine whether observed genomic instability was related to defective chromosome repair, Hsp70.1/3(-/-) and Hsp70.1/3(+/+) fibroblasts were treated with ionizing radiation (IR) alone or heat and IR. Exposure to IR led to more residual chromosome aberrations, radioresistant DNA synthesis (a hallmark of genomic instability), increased cell killing, and enhanced IR-induced oncogenic transformation in Hsp70.1/3(-/-) cells. Heat treatment prior to IR exposure enhanced cell killing, S-phase-specific chromosome damage, and the frequency of transformants in Hsp70.1/3(-/-) cells in comparison to Hsp70.1/3(+/+) cells. Both in vivo and in vitro studies demonstrate for the first time that Hsp70.1 and Hsp70.3 have an essential role in maintaining genomic stability under stress conditions.     

Isolation and some properties of dioxygenase and co-oxidase activities of adult human liver cytosolic lipoxygenase

The evidence presented here constitutes the first report on the occurrence of lipoxygenase (LO) activity in the adult human liver. LO activity was isolated free of hemoglobin from the whole liver cytosol by affinity chromatography using a concanavalin-A sepharose 4B column, and some properties of its dioxygenase and co-oxidase activities were examined. High-pressure liquid chromatography (HPLC) analyses of arachidonic acid metabolites suggested the presence of 5-, 12-, and 15-LO activities in the human liver. Linoleic acid was converted into 13-hydroperoxyoctadecadienoic acid. The dioxygenase activity with a V_max value of 1.74 μmoles/min/mg protein and a K_m value of 0.48 mM was noted in the presence of different concentrations of linoleic acid at pH 10. The activity was markedly stimulated by the presence of calcium, ATP, hydrogen peroxide, and KCl in the assay medium. Under optimum conditions, all the xenobiotics tested were co-oxidized by the enzyme preparations in the presence of linoleic acid. Kinetic data obtained for benzidine oxidation yielded a K_m value of 0.53 mM and a V_max value of 90.9 nmoles/min/mg protein. At present, the significance of these findings in in vivo toxicity of benzidine is unknown. The linoleic acid-dependent dioxygenase and co-oxidase activities were thermolabile and inhibited by micromolar concentrations of several classical LO inhibitors, further confirming the involvement of LO in these reactions. © 1997 John Wiley & Sons, Inc.