Phosphate solubilization potential and stress tolerance of Eupenicillium parvum from tea soil

Eupenicillium parvum was recorded for first time during isolation of phosphate-solubilizing microorganisms from the tea rhizosphere. The fungus developed a phosphate solubilization zone on modified Pikovskaya agar, supplemented with tricalcium phosphate. Quantitative estimation of phosphate solubilization in Pikovskaya broth showed high solubilization of tricalcium phosphate and aluminium phosphate. The fungus also solubilized North Carolina rock phosphate and Mussoorie rock phosphate, and exhibited high levels of tolerance against desiccation, acidity, salinity, aluminium, and iron. Solubilization of inorganic phosphates by the fungus was also observed under high stress levels of aluminium, iron, and desiccation, though the significant decline in phosphate solubilization was marked in the presence of aluminium than iron. The fungal isolate showed 100 % identity with E. parvum strain NRRL 2095 ITS 1, 5.8S rRNA gene and ITS 2, complete sequence; and 28S rRNA gene, partial sequence.     

Production, purification and characterization of thermostable phytase from thermophilic fungus Thermomyces lanuginosus TL-7

Ten different strains of Thermomyces lanuginosus, isolated from composting soils were found to produce phytase when grown on PSM medium. The wild type strain CM was found to produce maximum amount ofphytase (4.33 units/g DW substrate). Culturing T. lanuginosus strain CM on medium containing wheat bran and optimizing other culture conditions (carbon source, media type, nitrogen source, level of nitrogen, temperature, pH, inoculum age, inoculum level and moisture), increased the phytase yield to 13.26 units/g substrate. This culture was further subjected to UV mutagenesis for developing phytase hyperproducing mutants. The mutant (TL-7) showed 2.29-fold increase in phytase activity as compared to the parental strain. Employing Box-Behnken factor factorial design of response surface methodology resulted in optimized phytase production (32.19 units/g of substrate) by mutant TL-7. A simple two-step purification (40.75-folds) ofphytase from mutant TL-7 was achieved by anion exchange and gel filtration chromatography. The purified phytase (approximately 54 kDa) was characterized to be optimally active at pH 5.0 and temperature 70 degrees C, though the enzyme showed approximately 70% activity over a wide pH and temperature range (2.0-10.0 and 30-90 degrees C, respectively). The phytase showed broad substrate specificity with activity against sodium phytate, ADP and riboflavin phosphate. The phytase from T. lanuginosus was thermoacidstable as it showed up to 70% residual activity after exposure to 70 degrees C at pH 3.0 for 120 min. The enzyme showed Km 4.55 microM and Vmax 0.833 microM/min/mg against sodium phytate as substrate.     

Secular trends in prevalence of overweight and obesity from 2006 to 2009 in urban asian Indian adolescents aged 14-17 years

The present study examines the secular trends in prevalence of overweight and obesity among urban Asian Indian adolescents in New Delhi (North India). The data were derived from cross-sectional sampling of children, 3493 in year 2006 and 4908 in year 2009, aged 14-17 years studying in privately-funded and government-funded schools. Age, gender and Asian Indian-specific cut offs of body mass index (BMI) were used to define overweight and obesity. The prevalence of obesity increased significantly from 9.8% in 2006 to 11.7% in 2009 (p<0.01), whereas underweight decreased from 11.3% to 3.9% (p<0.001). There was a significantly higher risk of being overweight (OR 1.28; 95% CI, 1.15-1.42) and obese (OR 1.44; 95% CI, 1.24-1.66) in year 2009 than 2006, after adjusting for age, gender and type of school. Males and privately-funded school children had significantly higher increase in prevalence and risk of being overweight and obese over the three years. In conclusion, this study showed an increasing trend in prevalence of overweight and obesity in urban Asian Indian adolescents. More specifically, the study showed the association of this increasing trend of overweight and obesity prevalence with male gender and high socio-economic status, calling for an urgent need for immediate and targeted preventive measures.     

Seasonal seston stoichiometry: effects on zooplankton in cyanobacteria-dominated lakes

Seasonal dynamics in elemental composition [carbon (C), nitrogenand phosphorus (P)] of seston and zooplankton were studied overseveral years in three hypereutrophic Dutch lakes with persistentdominance and high biomass of cyanobacteria. In all three lakes,there was a strong pattern with decreased P-content and increasedC:P ratio in seston (<150 µm) coinciding with the increasein water temperature. The seston C:P ratios (at:at) were morethan doubled with the rising temperature, i.e. from 200 (at:at)in winter to 500 in summer. Sestonic C:P ratios increased overthe growing season, suggesting that seasonal dynamics amongautotrophs with high P-uptake in winter and support of subsequentphytoplankton growth by consumption of internal cellular P (P-quota)was the main cause of low sestonic P contents in late summer.This could, however, occur in concert with a physiologicallydriven decrease in cell-specific P at higher temperatures insummer. In contrast, the annual variation of C:P ratios of thezooplankton fraction was only 10% of that of seston. The variationsof C:P ratios of the zooplankton were, nevertheless, stronglycorrelated with those of seston. For most of the summer, sestonC:P ratios were far above the threshold ratio for P-limitationin Daphnia and other P-demanding species. This will pose furtherconstraints on growth performance of Daphnia in these lakes,thus adding to the fish predation pressure and the poor foodquality of cyanobacteria per se. The low grazing pressure causesa high biomass of low-quality autotrophs, promoting a stablestate with low trophic transfer efficiency.     

Effects of diesel exhaust, heavy metals and pesticides on various organ systems: possible mechanisms and strategies for prevention and treatment

Environmental pollutants have a significant impact on the ecosystem and disrupt balance between environment, human and non-human components that result in deleterious effects to all forms of life. Identifying environmental factors for potential imbalance are extremely crucial for devising strategies for combating such toxic dysregulation. Automobile exhaust (in air), heavy metals (in food and water) and pesticides (in air, food, soil and water) are the most common environmental pollutants and their short and long-term exposures can cause hazardous effects in humans leading to systemic disorders involving lungs, kidney and immune systems. Mechanisms involved in genesis of such toxic effects have revealed complex, interactive pathways. Strategies for the protection of homeostasis and health, viz., general preventive measures, nutritional supplements and herbal agents have been described, to counter these pollutants induced damaging effects on various body systems.     

Role of endothelin (ETA) receptors in neonatal morphine withdrawal

We have previously demonstrated role of central endothelin (ET) receptors in neonatal morphine tolerance. The present study was conducted to investigate involvement of central ET receptors in neonatal rat morphine withdrawal. The aim was to determine activation of G-proteins coupled to opioid and ET receptors by morphine and ET ligands in neonatal rat brains during morphine withdrawal. Pregnant female rats were rendered tolerant to morphine by chronic exposure to morphine pellets over 7 days. Withdrawal was induced on day 8 by removal of pellets. Rat pups were delivered by cesarean section 24 h after pellet removal. G-protein stimulation induced by morphine; ET-1; ETA receptor antagonist, BMS182874; and ETB receptor agonist, IRL1620, was determined in the brain of neonatal rats undergoing morphine withdrawal by [35S]GTPgammaS binding assay. Morphine-induced maximal stimulation of G-protein in morphine withdrawal group (83.60%) was significantly higher compared to placebo control group (66.81%). EC50 value for ET-1-induced G-protein stimulation during morphine withdrawal (170.60 nM) was higher than control (62.5 nM). BMS182874, did not stimulate GTP binding in control but significantly increased maximal stimulation of G-proteins in morphine withdrawal (86.07%, EC50 = 31.25 nM). IRL1620-induced stimulation of G-proteins was similar in control and morphine withdrawal. The present findings indicate involvement of central ETA receptors in neonatal morphine withdrawal.     

Biochemical characterization of ribosome assembly GTPase RbgA in Bacillus subtilis

The ribosome biogenesis GTPase A protein RbgA is involved in the assembly of the large ribosomal subunit in Bacillus subtilis, and homologs of RbgA are implicated in the biogenesis of mitochondrial, chloroplast, and cytoplasmic ribosomes in archaea and eukaryotes. The precise function of how RbgA contributes to ribosome assembly is not understood. Defects in RbgA give rise to a large ribosomal subunit that is immature and migrates at 45 S in sucrose density gradients. Here, we report a detailed biochemical analysis of RbgA and its interaction with the ribosome. We found that RbgA, like most other GTPases, exhibits a very slow k(cat) (14 h(-1)) and has a high K(m) (90 μM). Homology modeling of the RbgA switch I region using the K-loop GTPase MnmE as a template suggested that RbgA requires K(+) ions for GTPase activity, which was confirmed experimentally. Interaction with 50 S subunits, but not 45 S intermediates, increased GTPase activity by ～55-fold. Stable association with 50 S subunits and 45 S intermediates was nucleotide-dependent, and GDP did not support strong interaction with either of the subunits. GTP and guanosine 5'-(β,γ-imido)triphosphate (GMPPNP) were sufficient to promote association with the 45 S intermediate, whereas only GMPPNP was able to support binding to the 50 S subunit, presumably due to the stimulation of GTP hydrolysis. These results support a model in which RbgA promotes a late step in ribosome biogenesis and that one role of GTP hydrolysis is to stimulate dissociation of RbgA from the ribosome.     

Properdin is critical for antibody-dependent bactericidal activity against Neisseria gonorrhoeae that recruit C4b-binding protein

Gonorrhea, a sexually transmitted disease caused by Neisseria gonorrhoeae, is an important cause of morbidity worldwide. A safe and effective vaccine against gonorrhea is needed because of emerging resistance of gonococci to almost every class of antibiotic. A gonococcal lipooligosaccharide epitope defined by the mAb 2C7 is being evaluated as a candidate for development of an Ab-based vaccine. Immune Abs against N. gonorrhoeae need to overcome several subversive mechanisms whereby gonococcus evades complement, including binding to C4b-binding protein (C4BP; classical pathway inhibitor) and factor H (alternative pathway [AP] inhibitor). The role of AP recruitment and, in particular, properdin in assisting killing of gonococci by specific Abs is the subject of this study. We show that only those gonococcal strains that bind C4BP require properdin for killing by 2C7, whereas strains that do not bind C4BP are efficiently killed by 2C7 even when AP function is blocked. C3 deposition on bacteria mirrored killing. Recruitment of the AP by mAb 2C7, as measured by factor B binding, occurred in a properdin-dependent manner. These findings were confirmed using isogenic mutant strains that differed in their ability to bind to C4BP. Immune human serum that contained bactericidal Abs directed against the 2C7 lipooligosaccharide epitope as well as murine antigonococcal antiserum required functional properdin to kill C4BP-binding strains, but not C4BP-nonbinding strains. Collectively, these data point to an important role for properdin in facilitating immune Ab-mediated complement-dependent killing of gonococcal strains that inhibit the classical pathway by recruiting C4BP.