Brain PPAR-γ promotes obesity and is required for the insulin-sensitizing effect of thiazolidinediones

In adipose tissue, muscle, liver and macrophages, signaling by the nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ) is a determinant of insulin sensitivity and this receptor mediates the insulin-sensitizing effects of thiazolidinediones (TZDs). As PPAR-γ is also expressed in neurons, we generated mice with neuron-specific Pparg knockout (Pparg brain knockout (BKO)) to determine whether neuronal PPAR-γ signaling contributes to either weight gain or insulin sensitivity. During high-fat diet (HFD) feeding, food intake was reduced and energy expenditure increased in Pparg-BKO mice compared to Pparg(f/f) mice, resulting in reduced weight gain. Pparg-BKO mice also responded better to leptin administration than Pparg(f/f) mice. When treated with the TZD rosiglitazone, Pparg-BKO mice were resistant to rosiglitazone-induced hyperphagia and weight gain and, relative to rosiglitazone-treated Pparg(f/f) mice, experienced only a marginal improvement in glucose metabolism. Hyperinsulinemic euglycemic clamp studies showed that the increase in hepatic insulin sensitivity induced by rosiglitazone treatment during HFD feeding was completely abolished in Pparg-BKO mice, an effect associated with the failure of rosiglitazone to improve liver insulin receptor signal transduction. We conclude that excess weight gain induced by HFD feeding depends in part on the effect of neuronal PPAR-γ signaling to limit thermogenesis and increase food intake. Neuronal PPAR-γ signaling is also required for the hepatic insulin sensitizing effects of TZDs.     

Potential of 2D crosslinked sericin membranes with improved biostability for skin tissue engineering

Silk sericin protein is a natural, hydrophilic, macromolecular glycoprotein mainly synthesized in the middle silk gland of the silkworm. It constitutes 25–30% of the silk cocoon. Sericin proteins have antioxidant, antimicrobial, UV-resistant properties, promote wound healing and support cell proliferation even in serum-free media. Most of the sericin is discarded as waste in silk processing industries. This study aims at improving the mechanical strength and stability of sericin extracted from the silk cocoons during processing and utilize it as a biocompatible natural biopolymer in biomedical applications. Crosslinked sericin membranes, from the cocoon of non-mulberry tropical silkworm, Antheraea mylitta, were prepared using gluteraldehyde as the crosslinking agent. Physical and structural characteristics of the membranes were analyzed using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and X-ray diffraction along with swelling and degradation studies. The secondary structure of the membrane indicates that crosslinking provides a more integrated structure that significantly improves the stability and mechanical strength of the membranes. In vitro cytocompatibility of the membranes was evaluated by MTT assay and cell cycle analysis of feline fibroblast cells. The adherence, growth and proliferation patterns of cells on membranes were assessed by confocal microscopy, which demonstrated that the latter is non-toxic and supports cell growth. Cell cycle analyses indicate cytocompatibility with normal cell cycle pattern. This study reveals that silk sericin protein can be used as a biocompatible natural biopolymer for various applications in the biomedical field.     

In situ mortality of Hyposidra talaca (Geometridae: Lepidoptera) by its nucleopolyhedrovirus and comparison of tea production in untreated and chemical insecticide-treated plots

We had previously reported on HytaNPV infection in the looper caterpillars of Hyposidra talaca. Studying the pattern of cumulative daily mortality of looper caterpillars and comparing the post-looper crop production in microbial-control plots and insecticide-treated plots, we report that HytaNPV is a potential microbial agent of H. talaca.     

Dwarf mutations in grass pea (Lathyrus sativus L.): origin, morphology, inheritance and linkage studies

Induction of mutation has been used to create additional genetic variability in grass pea (Lathyrus sativus L.). During the ongoing investigations on different induced-morphological mutants, the author detected three types of dwarf mutants in grass pea. One mutant, designated as dwf1 type was earlier identified in colchicine-induced C₂ generation of grass pea variety BioR-231 while the other two, designated as dwf2 and dwf3 were isolated in 250 Gy and 300 Gy gamma ray irradiated M₂ progeny of variety ‘BioR-231’ and ‘Hooghly Local’, respectively. As compared to their parental varieties (controls), all the three mutants manifested stunted, erect and determinate stem, early maturity and tolerance to pod shattering habit. The mutants differed from each other, as well as with controls, in number of primary branches, nature of stipules and internodes, length of peduncle, leaflet and seed coat colour, seed yield and seed neurotoxin content. The three dwarf mutants were monogenically recessive and bred true in successive generations. F₂ segregation pattern obtained from the crosses involving the three mutants indicated that dwarf mutation in grass pea was controlled by two independent non-allelic genes, assigned as df1 (for dwf1 type), df2 (for dwf2 type) and df3 (for dwf3 type), with the df1 locus being multiple allelic. Primary trisomic analyses revealed the presence of df1/df2 locus on the extra chromosome of trisomic type I, whereas df3 was located on the extra chromosome of type III. Linkage studies involving five other phenotypic markers suggested linked association of df1/df2 locus with lfc (leaflet colour) and wgn (winged internode) and df3 locus with cbl (seed coat colour). Both the loci; however, assorted independently with flower colour and stipule character. The dwarf types can be utilized as valuable tools for further cytogenetic research and breeding of grass pea.     

Length–weight relationships of three small indigenous fish species from the Lower Brahmaputra,India

Length–weight relationships (LWRs) for three small indigenous fish species from the lower Brahmaputra in Assam, India: Glyptothorax telchitta, Nangra assamensis, and Gudusia chapra were studied on a monthly basis from February 2015 to January 2016. Various fishing gear types were employed: cast nets (9′ ½”), gillnets (30 × 0.9 m, 0.5″; 60 × 3 m, 1.5″) and mosquito nets (20 × 6 m, 0.04″). No previous reference is available on LWR data for two of these species.     

Length–weight relationships of two Nemacheilid fish species [Schistura fasciata Lokeshwor and Vishwanath, 2011 and Schistura reticulofasciata (Singh and Bănărescu, 1982)] from Simsang River,Meghalaya, India

Length–weight relationships (LWRs) are presented for two fish species: Schistura fasciata Lokeshwor and Vishwanath, 2011 and Schistura reticulofasciata (Singh and B?n?rescu, 1982), sampled from the Simsang River in Meghalaya, India. Fishes were caught seasonally from January to December 2015, with cast nets (10–15 mm mesh size) and electrofishing devices. The b values in the LWRs were determined as 3.09 for S. fasciata and 3.318 for S. reticulofasciata.