Functionalization of cellulosic fibers by graft copolymerization of acrylonitrile and ethyl acrylate from their binary mixtures

Functionalization of Agave fibers was carried out by graft copolymerization of acrylonitrile (AN) and ethyl acrylate (EA) from their binary solutions in presence of Ce (IV) ions at a temperature of 45 ± 0.1 °C. An increase in the graft copolymerization was obtained with the increase in the feed molarity of the comonomers up to certain extent. Contrary to lesser affinity of acrylonitrile to grafting on Agave fibers, a synergistic effect of ethyl acrylate on acrylonitrile was observed when graft copolymers were prepared using different feed compositions (f_AN). The graft copolymers were characterized by various techniques such as FT-IR, TGA/DTA, X-RD and SEM analysis. Further swelling behavior of grafted fibers in different solvents, moisture absorption behavior and resistance to chemicals was investigated as a function of percent grafting to define their end uses in different environments.     

Assessment of drug-induced mitochondrial dysfunction via altered cellular respiration and acidification measured in a 96-well platform

High-throughput applicable screens for identifying drug-induced mitochondrial impairment are necessary in the pharmaceutical industry. Hence, we evaluated the XF96 Extracellular Flux Analyzer, a 96-well platform that measures changes in the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) of cells. The sensitivity of the platform was bench-marked with known modulators of oxidative phosphorylation and glycolysis. Sixteen therapeutic agents were screened in HepG2 cells for mitochondrial effects. Four of these compounds, thiazolidinediones, were also tested in primary feline cardiomyocytes for cell-type specific effects. We show that the XF96 platform is a robust, sensitive system for analyzing drug-induced mitochondrial impairment in whole cells. We identified changes in cellular respiration and acidification upon addition of therapeutic agents reported to have a mitochondrial effect. Furthermore, we show that respiration and acidification changes upon addition of the thiazoldinediones were cell-type specific, with the rank order of mitochondrial impairment in whole cells being in accord with the known adverse effects of these drugs.     

Dally and Notum regulate the switch between low and high level Hedgehog pathway signalling

During development, secreted morphogens, such as Hedgehog (Hh), control cell fate and proliferation. Precise sensing of morphogen levels and dynamic cellular responses are required for morphogen-directed morphogenesis, yet the molecular mechanisms responsible are poorly understood. Several recent studies have suggested the involvement of a multi-protein Hh reception complex, and have hinted at an understated complexity in Hh sensing at the cell surface. We show here that the expression of the proteoglycan Dally in Hh-receiving cells in Drosophila is necessary for high but not low level pathway activity, independent of its requirement in Hh-producing cells. We demonstrate that Dally is necessary to sequester Hh at the cell surface and to promote Hh internalisation with its receptor. This internalisation depends on both the activity of the hydrolase Notum and the glycosyl-phosphatidyl-inositol (GPI) moiety of Dally, and indicates a departure from the role of the second glypican Dally-like in Hh signalling. Our data suggest that hydrolysis of the Dally-GPI by Notum provides a switch from low to high level signalling by promoting internalisation of the Hh-Patched ligand-receptor complex.     

Influence of co-inoculation of bacteria-cyanobacteria on crop yield and C–N sequestration in soil under rice crop

The performance of three selected bacterial strains—PR3, PR7 and PR10 (Providencia sp., Brevundimonas sp., Ochrobacterium sp.) and three cyanobacterial strains CR1, CR2 and CR3 (Anabaena sp., Calothrix sp., Anabaena sp.), and their combinations was evaluated in a pot experiment with rice variety Pusa-1460, comprising 51 treatments along with recommended fertilizer controls. Highest yield enhancement of 19.02% was recorded in T12 (CR2), over control, while significant enhancement in nitrogen fixing potential was recorded in treatments involving combination of bacterial-cyanobacterial strains—T37 (PR3 + CR1 + CR3) and T21 (PR7 + CR1). Organic carbon was significantly increased in all microbe-inoculated treatments, which could be correlated with microbial biomass carbon values and activities of all the enzymes tested in our study. Also, panicle weight and plant biomass were highly correlated with soil microbial carbon. Comparative evaluation revealed the superior performance of strains CR2, CR1 (both Anabaena sp.) and PR10 (Ochrobacterium sp.) in increasing the growth and grain yield of rice and improving soil health, besides N (nitrogen) savings of 40–80 kg ha⁻¹. The study for the first time illustrated the positive effects of co-inoculation of bacterial and cyanobacterial strains for integrated nutrient management of rice crop.     

Cadmium tolerance and its phytoremediation by two oil yielding plants Ricinus communis (L.) and Brassica juncea (L.) from the contaminated soil

The effect of increasing level of cadmium in soil was investigated on biomass production, antioxidants, Cd bioaccumulation and translocation in Ricinus communis vis-à-vis a commonly studied oil crop Brassica juncea. The plants were exposed to 25, 50, 75, 100, and 150 mg Cd/Kg soil for up to 60 days. It was found that R. communis produced higher biomass at all the contamination levels than that of B. juncea. Proline and malondialdehyde in the leaves increased with increase in Cd level in both the species, whereas soluble protein decreased. The bioaccumulation of Cd was higher in B. juncea on the basis of the per unit biomass, total metal accumulation per plant was higher in R. communis. The translocation of Cdfrom roots to shoot was also higher in B. juncea at all Cd concentrations. R. communis appeared more tolerant and capable to clean Cd contaminated soil for longer period in one sowing than B. juncea and the former can grow in wasteland soil also in which later cannot be cultivated.     

A 12-deoxywithastramonolide-rich somaclonal variant in Withania somnifera (L.) Dunal—molecular cytogenetic analysis and significance as a chemotypic resource

Withania somnifera, commonly known as ashwagandha or Indian ginseng, is a valuable medicinal plant, synthesizing a wide array of pharmacologically active secondary metabolites known as withanolides. In this study, we investigated variation among 54 regenerated plants attained through indirect organogenesis from leaf explants. Organogenic calli were induced on Murashige and Skoog medium containing 2?mg?l^?1 kinetin and 1?mg?l^?1 indole-3-butyric acid. High-performance liquid chromatography was used for quantitative determination of the major withanolides in the somaclones. One somaclone (WS-R-1) showed significantly higher accumulation of 12-deoxywithastramonolide (WS-12D; 0.516%) compared to the explant donor mother plant (0.002%). The incidence of somaclonal variation at the cytological level was investigated by studying mitosis and meiosis in relation to chromosome number and structural organization. There were no alterations in chromosome phenotypes, somatic chromosome count, or meiotic behavior. Fidelity at genomic level was evaluated by random amplification of polymorphic DNA (RAPD) analyses, which revealed multiple genetic polymorphisms between the WS-12D over-producing somaclone and the explant donor mother plant. This study demonstrates the capability of inducing chemotypic variability for the development of high-yielding clones due to molecular instability in W. somnifera using an in vitro approach.     

Molecular Epidemiology of Influenza A(H1N1)pdm09 Viruses from Pakistan in 2009-2010

Background

In early 2009, a novel influenza A(H1N1) virus that emerged in Mexico and United States rapidly disseminated worldwide. The spread of this virus caused considerable morbidity with over 18000 recorded deaths. The new virus was found to be a reassortant containing gene segments from human, avian and swine influenza viruses.

Methods/Results

The first case of human infection with A(H1N1)pdm09 in Pakistan was detected on 18^th June 2009. Since then, 262 laboratory-confirmed cases have been detected during various outbreaks with 29 deaths (as of 31^st August 2010). The peak of the epidemic was observed in December with over 51% of total respiratory cases positive for influenza. Representative isolates from Pakistan viruses were sequenced and analyzed antigenically. Sequence analysis of genes coding for surface glycoproteins HA and NA showed high degree of high levels of sequence identity with corresponding genes of regional viruses circulating South East Asia. All tested viruses were sensitive to Oseltamivir in the Neuraminidase Inhibition assays.

Conclusions

Influenza A(H1N1)pdm09 viruses from Pakistan form a homogenous group of viruses. Their HA genes belong to clade 7 and show antigenic profile similar to the vaccine strain A/California/07/2009. These isolates do not show any amino acid changes indicative of high pathogenicity and virulence. It is imperative to continue monitoring of these viruses for identification of potential variants of high virulence or drug resistance.     

Expression of Mutant Huntingtin in Leptin Receptor-Expressing Neurons Does Not Control the Metabolic and Psychiatric Phenotype of the BACHD Mouse

Metabolic and psychiatric disturbances occur early on in the clinical manifestation of Huntington’s disease (HD), a neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin (HTT) gene. Hypothalamus has emerged as an important site of pathology and alterations in this area and its neuroendocrine circuits may play a role in causing early non-motor symptoms and signs in HD. Leptin is a hormone that controls energy homeostasis by signaling through leptin receptors in the hypothalamus. Disturbed leptin action is implicated in both obesity and depression and altered circulating levels of leptin have been reported in both clinical HD and rodent models of the disease. Pathological leptin signaling may therefore be involved in causing the metabolic and psychiatric disturbances of HD. Here we tested the hypothesis that expression of mutant HTT in leptin receptor carrying neurons plays a role in the development of the non-motor phenotype in the BACHD mouse model. Our results show that inactivation of mutant HTT in leptin receptor-expressing neurons in the BACHD mouse using cross-breeding based on a cre-loxP system did not have an effect on the metabolic phenotype or anxiety-like behavior. The data suggest that mutant HTT disrupts critical hypothalamic pathways by other mechanisms than interfering with intracellular leptin signaling.     

Urinary metabolomic phenotyping of nickel induced acute toxicity in rat: an NMR spectroscopy approach

The metabolomic approach has been widely used in toxicology to investigate mechanisms of toxicity. To understand the mammalian system??s response to nickel exposure, we analysed the NiCl₂ induced metabolomic changes in urine of rats using ¹H nuclear magnetic resonance (¹H NMR) spectroscopy together with clinically relevant biochemical parameters. Male Sprague?CDawley rats were administered intraperitoneally with NiCl₂ at doses of 4, 10 and 20?mg/kg body weight. Urine samples were collected at 8, 16, 24, 72, 96 and 120?h post treatment. The metabolomic profile of rat urine showed prominent changes in citrate, dimethylamine, creatinine, choline, trimethylamine oxide (TMAO), phenyl alanine and hippurate at all doses. Principal component analysis of urine ¹H NMR spectra demonstrated the dose and time dependent development of toxicity. The metabolomic time trajectory, based on pattern recognition analysis of ¹H NMR spectra of urine, illustrated clear separation of pre and post treatments (temporal). Only animals treated with a low dose of NiCl₂ returned to normal physiology. The ¹H NMR spectral data correlated well with the clinically relevant nephrotoxic biomarkers. The urinary metabolomic phenotyping for NiCl₂ induced nephrotoxicity was defined according to the predictive ability of the known metabolite biomarkers, creatinine, citrate and TMAO. The current approach demonstrates that metabolomics, one of the most important platform in system biology, may be a promising tool for identifying and characterizing biochemical responses to toxicity.     

Study of semiconducting nanomaterials under pressure

The pressure induced structural and mechanical properties of nanocrystalline ZnO, ZnS, ZnSe, GaN, CoO, CdSe, CeO(2), SnO(2), SiC, c-BC(2)N, and β-Ga(2)O(3) with different grain sizes have been analyzed under high pressures. The molecular dynamics simulation model has been used to compute isothermal equation of state, volume collapse and bulk modulus of these materials in nano and bulk phases at ambient and high pressures and compared with the experimental data. It is evident from these calculations that the change in particle size affects directly the phase transition pressure and bulk modulus. The values of phase transition pressure and bulk modulus increase with decrease in grain size of the material. The equilibrium cell volume and volume collapse in parent phase is directly proportional to the grain size of the materials. Present results are in good agreement with experimental data. The model is able to explain these thermodynamic properties at varying temperatures and pressures successfully.