Fishing cat Prionailurus viverrinus distribution and habitat suitability in Nepal

The fishing cat Prionailurus viverrinus is a wetland specialist species endemic to South and Southeast Asia. Nepal represents the northern limit of its biogeographic range, but comprehensive information on fishing cat distribution in Nepal is lacking. To assess their distribution, we compiled fishing cat occurrence records (n = 154) from Nepal, available in published literature and unpublished data (2009–2020). Bioclimatic and environmental variables associated with their occurrence were used to predict the fishing cat habitat suitability using MaxEnt modeling. Fishing cat habitat suitability was associated with elevation (152–302 m), precipitation of the warmest quarter, i.e., April–June (668–1014 mm), precipitation of the driest month (4–7 mm), and land cover (forest/grassland and wetland). The model predicted an area of 4.4% (6679 km²) of Nepal as potential habitat for the fishing cat. About two‐thirds of the predicted potentially suitable habitat lies outside protected areas; however, a large part of the highly suitable habitat (67%) falls within protected areas. The predicted habitat suitability map serves as a reference for future investigation into fishing cat distribution as well as formulating and implementing effective conservation programs in Nepal. Fishing cat conservation initiatives should include habitats inside and outside the protected areas to ensure long‐term survival. We recommend conservation of wetland sites, surveys of fishing cats in the identified potential habitats, and studying their genetic connectivity and population status.     

Changes in nuclear proteins of astrocytes as a result of acute ammonia or ethanol exposure

We have used an in vitro system to monitor the effects of high levels of ammonia and ethanol on glial cells. Nuclei were isolated and the protein profiles examined by two-dimensional gel electrophoresis. Acute exposure of rat astrocyte cell cultures to ammonia or ethanol resulted in changes in cellular morphology and the level of some nuclear proteins. Glial fibrillary acidic protein (GFAP) levels remained constant under both treatments. Several nuclear proteins were increased specifically. Only one protein was visually detected which was unique to treatment with ammonia or ethanol. This protein (p2a) appeared only in the presence of ammonia. There were no changes in previously observed astrocyte-associated proteins (Silverman et al. Neurochem Int. 12, 513–518, 1988). Two proteins appeared de novo upon either treatment with either ammonia or ethanol. These latter proteins had a molecular weight and pI profile similar to the major class of nuclear stress proteins (hsp70). However, results from immunoblot experiments clearly demonstrated that hsp70 was not induced in astroycte cultures following exposure to ammonia or ethanol.     

Reductive dechlorination of perchloroethylene and the role of methanogens

Abstract Perchloroethylene (PCE) was reductively dechlorinated to trichloroethylene in a 10% anaerobic sewage sludge. About 80% of the initially added PCE (300 nmol) was dechlorinated within three weeks. The calculated rates were 250 nM and 445 nM · day⁻¹ during the first and second weeks of incubation, respectively. The depletion of PCE varied in sludges obtained from different sources.
The role of methanogenesis in the dechlorination of PCE was evaluated by inhibiting the methanogens by addition of bromoethane sulfonic acid, a potent methanogenic inhibitor. Dechlorination of PCE was significantly inhibited in sludges amended with the inhibitor. Almost 41–48% less PCE was dechlorinated in sludges containing 5 mM BESA, indicating a relation between the two processes (methanogenesis and dechlorination). Direct proof that methanogens can transform chlorinated aliphatic compounds was obtained using axenic cultures of acetate-cleaving methanogens. Methanosarcina sp , originally isolated from a chlorophenol degrading consortium, showed significantly higher dechlorinating activity as compared to Ms. mazei . Based on these studies and other recently reported observations, it appears that methanogens/methanogenesis play an important role in the anaerobic dechlorination of chlorinated aliphatics such as PCE.     

Oxidative stress and the development of diabetic complications - antioxidants and lipid peroxidation in erythrocytes and cell membrane.

Erythrocytes isolated from 131 cases of Non-Insulin Dependent Diabetes Mellitus (NIDDM) were studied for lipid peroxidation, antioxidant defences, and the maximum peroxidisable substrate in the cell membrane. Antioxidant defences are lowered in NIDDM, followed by significant rise in lipid peroxidation products. However, in the erythrocyte membrane, the total polyunsaturated peroxidisable lipids are lower than in normal erythrocytes which may be a causative factor affecting the survival of the cells.     

Polymerase chain reaction and its applications: special emphasis on its role in embryo sexing

The polymerase chain reaction (PCR) has developed into one of the most promising methods for in vitro enzymatic amplification of DNA and has found widespread application in DNA cloning, sequencing and mutagenesis related studies. This innovative technique can selectively amplify a single target DNA molecule a billion-fold in a span of a few hours. Amplification of specific DNA sequences by PCR is useful in identification of sex, novel genes, pathogens and diseases. PCR has facilitated the establishment of evolutionary relationships among species and in revealing structural intricacies of single cells. In this article we review some of the major advances and applications of PCR, especially, its role in embryo sexing.     

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.     

Effect of phenol on protein and amino acid content of Xanthomonas oryzae pv. oryzae

Leaf blight disease of rice (Oryza sativa) is caused by the bacterium Xanthomonas oryzae pv. oryzae. Phenol (1 to 4 mM) induced changes in protein profiles of X. o. pv. oryzae and a stress protein with a molecular mass of 69,000 appeared. HPLC analysis indicated occurrence of amino acids such as asparagine, alanine, methionine and cystine in phenol treated cells. Proton NMR analysis also revealed variation on the presence of amino acids in the cells treated with phenol.     

Delay in sexual maturity of the follicle-stimulating hormone receptor knockout male mouse

In the highly organized and complex process of mammalian spermatogenesis, the development of an undifferentiated diploid germ cell into a fully differentiated and mature spermatozoon is orchestrated in a time frame unique for each species including man. If the various hormonal signals including environmental cues that play a critical part in initiating these events are not properly executed, various deficiencies including delay in sexual maturity or puberty are likely. In this study we have followed testicular development and spermatogenesis in the FSH receptor knockout (FORKO) mice from Day 7 onward by using histology and quantitative DNA flow cytometry. The drastic reduction in testicular weight and shrinkage of seminiferous tubules that occurred at this early age persisted into the adult stage in the FORKOs, suggesting inhibition of the initial developmental processes. The round spermatids that were clearly abundant on Day 21 in the wild-type and heterozygous males were few and present only in some tubules of the FORKOs. There were no elongated spermatids in FORKO males on Day 35. The sperm produced by Day 49 FORKOs were already aberrant, a feature that persisted into adulthood in these animals. As all these changes occurred in a background of normal circulating testosterone levels, we may conclude that the delay in testicular development is a consequence of the loss of FSH-receptor signaling. The delay in sexual maturity of FORKOs was accompanied by reduction in fertility as evidenced by mating studies. Based on these data we suggest that the FORKO mouse might be a useful experimental model to define the molecular mechanisms that underlie the delay in puberty.     

Involvement of the MAP kinase pathways in induction of GADD45 following UV radiation

Indian hedgehog (Ihh) is highly expressed in prehypertrophic chondrocytes in vivo and has been proposed to regulate the proliferation and maturation of chondrocytes and bone collar formation in the growth plate. In high-density cultures of rabbit growth-plate chondrocytes, Ihh mRNA was also expressed at the highest level in the prehypertrophic stage. To explore endogenous factors that regulate Ihh expression in chondrocytes, we examined the effects of various growth factors on Ihh mRNA expression in this system. Retinoic acid (RA) and bone morphogenetic protein-2 enhanced Ihh mRNA expression, whereas PTH/PTH-related peptide (PTHrP) markedly suppressed Ihh expression. RA at more than 10(-8) M induced the expression of Ihh and Patched 1 (Ptc1) within 3 h, before it increased the type X collagen mRNA level at 6-24 h. Cycloheximide blocked the up-regulation of Ihh by RA, indicating the requirement of de novo protein synthesis for this stimulation. These findings suggest that RA is involved in the up-regulation of Ihh during endochondral bone formation. In contrast to RA, PTH (1-84) at 10(-7) M abolished the mRNA expression of Ihh and Ptc1 within 2-4 h, before it suppressed the expression of type X collagen at 12-24 h. The inhibition of Ihh expression by PTH (1-84) did not require de novo protein synthesis. PTH (1-34), PTHrP (1-34), and (Bu)(2)cAMP also suppressed Ihh expression. On the other hand, Ihh has been reported to induce PTHrP synthesis in the perichondrium. Consequently, the direct inhibitory action of PTH/PTHrP on Ihh appears to be a negative feedback mechanism that prevents excess PTHrP accumulation in cartilage.