Overall and central obesity and risk of type 2 diabetes in U.S. black women

Objective: Obesity has risen to epidemic proportions in the United States, leading to an emerging epidemic of type 2 diabetes. African‐American women are disproportionately affected by both conditions. While an association of overall obesity with increasing risk of diabetes has been documented in black women, the effect of fat distribution, specifically abdominal obesity, has not been studied. We examined the association of BMI, abdominal obesity, and weight gain with risk of type 2 diabetes. Research Methods and Procedures: During eight years of follow‐up of 49,766 women from the Black Women's Health Study, 2472 incident cases of diabetes occurred. Cox proportional hazard models were used to estimate incidence rate ratios (IRRs), with control for age, physical activity, family history of diabetes, cigarette smoking, years of education, and time period of data collection. Results: Sixty‐one percent of participants had a BMI ≥25 kg/m² (WHO definition of overweight). Compared with a BMI of <23 kg/m², the IRR for a BMI of >45 kg/m² was 23 (95% confidence interval, 17.0 to 31.0). The IRR for the highest quintile of waist‐to‐hip ratio relative to the lowest was 2.3 (95% confidence interval, 2.0 to 2.7) after control for BMI. Furthermore, at every level of BMI, an increased risk was observed for high waist‐to‐hip ratio relative to low. Discussion: Central obesity, as well as overall obesity, is a strong risk factor for diabetes in African‐American women. Efforts to reduce the prevalence of obesity in African‐American women are of paramount importance.     

Engineering the melanocortin-4 receptor to control constitutive and ligand-mediated G(S) signaling in vivo

The molecular and functional diversity of G protein-coupled receptors is essential to many physiological processes. However, this diversity presents a significant challenge to understanding the G protein-mediated signaling events that underlie a specific physiological response. To increase our understanding of these processes, we sought to gain control of the timing and specificity of G(s) signaling in vivo. We used naturally occurring human mutations to develop two G(s)-coupled engineered receptors that respond solely to a synthetic ligand (RASSLs). Our G(s)-coupled RASSLs are based on the melanocortin-4 receptor, a centrally expressed receptor that plays an important role in the regulation of body weight. These RASSLs are not activated by the endogenous hormone alpha-melanocyte-stimulating hormone but respond potently to a selective synthetic ligand, tetrahydroisoquinoline. The RASSL variants reported here differ in their intrinsic basal activities, allowing the separation of the effects of basal signaling from ligand-mediated activation of the G(s) pathway in vivo. These RASSLs can be used to activate G(s) signaling in any tissue, but would be particularly useful for analyzing downstream events that mediate body weight regulation in mice. Our study also demonstrates the use of human genetic variation for protein engineering.     

Draft genome sequence of Staphylococcus aureus 118 (ST772), a major disease clone from India

We report the draft genome sequence of an ST772 Staphylococcus aureus disease isolate carrying staphylococcal cassette chromosome mec (SCCmec) type V from a pyomyositis patient. Our de novo short read assembly is ∼2.8 Mb and encodes a unique Panton-Valentine leukocidin (PVL) phage with structural genes similar to those of φ7247PVL and novel lysogenic genes at the N termini.     

Development of Bed Reactor Using Brick Dust Immobilized CIVI-Cellulase from Seeds of Cowpea (Vigna sinensis L)

Cellulase extracted from seeds of Cowpea (Vigna sinensis L var VITA-4) was partially purified and immobilized on brick dust as solid support via glutaraldehyde. The percentage retention of the enzyme activity on brick dust was nearly 85%. After immobilization specific activity of the enzyme increased from 0.275 to 0.557 U mg^?1 protein with about 2 fold enrichment. The optimum pH and temperature of soluble enzyme were determined as pH 4.6 and WC, respectively whereas immobilized enzyme showed at pH 5.0 and 37°C, respectively. The V_max values for soluble and immobilized enzyme were determined as 6.67 and 1.25 mg min^?1, respectively whereas K_m values were 4.35 and 4.76 mg ml^?1, respectively. The immobilized enzyme displayed higher thermal stability than soluble enzyme and retained about 50% of its initial activity after 12 reuses. Immobilized enzyme was packed in an indigenously designed double walled glass bed reactor for continuous production of reducing sugars.     

BI‐69A11‐mediated inhibition of AKT leads to effective regression of xenograft melanoma

The AKT/PKB pathway plays a central role in tumor development and progression and is often up‐regulated in different tumor types, including melanomas. We have recently reported on the in silico approach to identify putative inhibitors for AKT/PKB. Of the reported hits, we selected BI‐69A11, a compound which was shown to inhibit AKT activity in in vitro kinase assays. Analysis of BI‐69A11 was performed in melanoma cells, a tumor type that commonly exhibits up‐regulation of AKT. Treatment of the UACC903 human melanoma cells, harboring the PTEN mutation, with BI‐69A11 caused efficient inhibition of AKT S473 phosphorylation with concomitant inhibition of AKT phosphorylation of PRAS40. Treatment of melanoma cells with BI‐69A11 also reduced AKT protein expression, which coincided with inhibition of AKT association with HSP‐90. BI‐69A11 treatment not only caused cell death of melanoma, but also prostate tumor cell lines. Notably, the effect of BI‐69A11 on cell death was more pronounced in cells that express an active form of AKT. Significantly, intra‐peritoneal injection of BI‐69A11 caused effective regression of melanoma tumor xenografts, which coincided with elevated levels of cell death. These findings identify BI‐69A11 as a potent inhibitor of AKT that is capable of eliciting effective regression of xenograft melanoma tumors.     

Optimization of medium for lipase production by Acinetobacter haemolyticus from healthy human skin

A lipase producing Acinetobacter haemolyticus TA106 was isolated from healthy human skin of tribal population. The maximum activity of 55 U/ml was observed after medium optimization using the "one variable at a time" and the statistical approaches. The optimal composition of the medium was determined as (% w/v or v/v): tryptone--1, yeast extract--0.5, sodium chloride-1, olive oil-1, Tween-80 1, manganese sulphate--5 mM, sucrose--1, pH-7. It was found that maximum production occurred in late log phase, i.e., after 72 h and at 200 rpm. From factorial design and statistical analysis, it was found that pH, temperature, salt, inoculum density and aeration significantly affected the lipase production. It was also noted that inoculum density of 3% (v/v), sucrose (1% w/v) and manganese sulphate (5 mM) displayed maximum lipase activity of 55 U/ml by conventional as well as statistical method. Optimization studies also indicated the increase in specific activity from 0.2 U/mg to 6.7 U/mg.     

Circular Permutation Provides an Evolutionary Link between Two Families of Calcium-dependent Carbohydrate Binding Modules

The microbial deconstruction of the plant cell wall is a critical biological process, which also provides important substrates for environmentally sustainable industries. Enzymes that hydrolyze the plant cell wall generally contain non-catalytic carbohydrate binding modules (CBMs) that contribute to plant cell wall degradation. Here we report the biochemical properties and crystal structure of a family of CBMs (CBM60) that are located in xylanases. Uniquely, the proteins display broad ligand specificity, targeting xylans, galactans, and cellulose. Some of the CBM60s display enhanced affinity for their ligands through avidity effects mediated by protein dimerization. The crystal structure of vCBM60, displays a β-sandwich with the ligand binding site comprising a broad cleft formed by the loops connecting the two β-sheets. Ligand recognition at site 1 is, exclusively, through hydrophobic interactions, whereas binding at site 2 is conferred by polar interactions between a protein-bound calcium and the O2 and O3 of the sugar. The observation, that ligand recognition at site 2 requires only a β-linked sugar that contains equatorial hydroxyls at C2 and C3, explains the broad ligand specificity displayed by vCBM60. The ligand-binding apparatus of vCBM60 displays remarkable structural conservation with a family 36 CBM (CBM36); however, the residues that contribute to carbohydrate recognition are derived from different regions of the two proteins. Three-dimensional structure-based sequence alignments reveal that CBM36 and CBM60 are related by circular permutation. The biological and evolutionary significance of the mechanism of ligand recognition displayed by family 60 CBMs is discussed.     

IgG1 is pathogenic in Leishmania mexicana infection

There are >2 million new cases of leishmaniasis annually, and no effective vaccine has been developed to prevent infection. In murine infection, Leishmania mexicana, which lives intracellularly in host macrophages, has developed pathways to hijack host IgG to induce a suppressive IL-10 response through FcγRs, the cell-surface receptors for IgG. To guide vaccine development away from detrimental Ab responses, which can accompany attempts to induce cell-mediated immunity, it is crucial to know which isotypes of IgG are pathogenic in this infection. We found that IgG1 and IgG2a/c induce IL-10 from macrophages in vitro equally well but through different FcγR subtypes: IgG1 through FcγRIII and IgG2a/c through FcγRI primarily, but also through FcγRIII. In sharp contrast, mice lacking IgG1 develop earlier and stronger IgG2a/c, IgG3, and IgM responses to L. mexicana infection and yet are more resistant to the infection. Thus, IgG1, but not IgG2a/c or IgG3, is pathogenic in vivo, in agreement with prior studies indicating that FcγRIII is required for chronic disease. This calls into question the assumption that macrophages, which should secrete IL-10 in response to IgG1 and IgG2a/c immune complexes, are the most important source of IL-10 generated by IgG-FcγR engagement in L. mexicana infection. Further investigations are required to better determine the cell type responsible for this immunosuppressive FcγRIII-induced IL-10 pathway and whether IgG2a/c is protective.     

Variable patterns of density-dependent survival in social bacteria

In numerous species of social animals and social microorganisms,fitness is positively dependent on population density, at leastin some environments and over some density ranges. This "Alleeeffect" is observed in the cooperative bacterium Myxococcusxanthus during multicellular fruiting body development, duringwhich the standard laboratory genotype sporulates less efficientlyat lower population densities and produces no spores below aminimum threshold density. Here we demonstrate significant quantitativevariation in Allee patterns among distinct natural isolatesof M. xanthus. Isolates with similar developmental performanceat intermediate population densities exhibit stark variationin performance at both very low and very high densities. Suchvariation has implications for evolutionary performance underfluctuating natural environments. It also suggests that distinctintraspecific populations of social animals and other socialmicrobes with different selective histories may vary in theeffects of density on social fitness.