Proteome-wide analysis of single-nucleotide variations in the N-glycosylation sequon of human genes

N-linked glycosylation is one of the most frequent post-translational modifications of proteins with a profound impact on their biological function. Besides other functions, N-linked glycosylation assists in protein folding, determines protein orientation at the cell surface, or protects proteins from proteases. The N-linked glycans attach to asparagines in the sequence context Asn-X-Ser/Thr, where X is any amino acid except proline. Any variation (e.g. non-synonymous single nucleotide polymorphism or mutation) that abolishes the N-glycosylation sequence motif will lead to the loss of a glycosylation site. On the other hand, variations causing a substitution that creates a new N-glycosylation sequence motif can result in the gain of glycosylation. Although the general importance of glycosylation is well known and acknowledged, the effect of variation on the actual glycoproteome of an organism is still mostly unknown. In this study, we focus on a comprehensive analysis of non-synonymous single nucleotide variations (nsSNV) that lead to either loss or gain of the N-glycosylation motif. We find that 1091 proteins have modified N-glycosylation sequons due to nsSNVs in the genome. Based on analysis of proteins that have a solved 3D structure at the site of variation, we find that 48% of the variations that lead to changes in glycosylation sites occur at the loop and bend regions of the proteins. Pathway and function enrichment analysis show that a significant number of proteins that gained or lost the glycosylation motif are involved in kinase activity, immune response, and blood coagulation. A structure-function analysis of a blood coagulation protein, antithrombin III and a protease, cathepsin D, showcases how a comprehensive study followed by structural analysis can help better understand the functional impact of the nsSNVs.     

Lack of association between Glu298Asp polymorphism and coronary artery disease in North Indians

Nitric Oxide (NO) is an important molecule carrying number of different functions in humans. Published studies suggest that it may inhibit several key steps involved in the pathogenesis of atherosclerosis. Inhibition or reduction of NO due to Glu298Asp polymorphism may accelerate atherosclerosis. The aim of this study was to determine whether Glu298Asp polymorphism is implicated in the pathogenesis of coronary artery disease (CAD) among North Indian population from the state of Uttar Pradesh, India. We selected 253 CAD patients and 174 healthy, normotensive, non-diabetic controls, which were matched for gender and ethnicity. The Glu298Asp (rs1799983) variant was detected by genotyping subjects, using a polymerase chain reaction followed by restriction fragment length polymorphism. There was no significant difference found in the genotypic and allelic frequencies between patients and controls. Our study indicated that Glu298Asp polymorphism does not play any critical role in the pathogenesis of CAD, at least in North Indian population.     

Redox active molecules cytochrome c and vitamin C enhance heme-enzyme peroxidations by serving as non-specific agents for redox relay

We report that incorporation of very low concentrations of redox protein cytochrome c and redox active small molecule vitamin C impacted the outcome of one-electron oxidations mediated by structurally distinct plant/fungal heme peroxidases. Evidence suggests that cytochrome c and vitamin C function as a redox relay for diffusible reduced oxygen species in the reaction system, without invoking specific or affinity-based molecular interactions for electron transfers. The findings provide novel perspectives to understanding - (1) the promiscuous role of cytochrome b(5) in the metabolism mediated by liver microsomal xenobiotic metabolizing systems and (2) the roles of antioxidant molecules in affording relief from oxidative stress.     

Brain metastasis from cervical carcinoma--a case report

Brain metastases from cervical carcinomas are extremely rare. We report a patient with squamous cell carcinoma of the cervix who developed an isolated left parietooccipital lobe metastasis within 4 months of treatment of the primary disease. The presenting symptoms of the metastatic disease were visual disturbance, headache, and vomiting. The patient was successfully treated by surgical excision of the metastasis and adjuvant whole brain radiation therapy, and she was disease-free at the 6-month follow-up after treatment of the recurrence.     

Baculovirus studies in new,indigenous lepidopteran cell lines

Eight lepidopteran cell lines were established recently and their susceptibility to different insect viruses was studied. Two Spodoptera litura cell lines from the larval and pupal ovaries, were found highly susceptible to S. litura nuclear polyhedrosis virus (SLNPV, 5-6 x 10(6) NPV/ml). The Helicoverpa armigera cell line from the embryonic tissue was highly susceptible to H. armigera NPV (HaNPV, 6.3 x 10(6) NPV/ml). These in vitro grown SLNPV and HaNPV caused 100% mortality to respective 2nd instar larvae. The susceptibility of the cryo-preserved cell lines to respective baculoviruses (SLNPV/HaNPV) was studied and no significant difference in their susceptibility status was observed. The cultures could grow as suspension culture on shakers and may find application for in vitro production of wild type/recombinant baculoviruses as bio-insecticides. S. litura and Bombyx mori cell lines from larval ovaries, were highly susceptible to Autographa californica NPV (5.5 x 10(6) NPV/ml) and Bombyx mori NPV (BmNPV, 6.1 x 10(6) NPV/ml) respectively. These cell lines may find application in baculovirus expression vector studies for the production of recombinant proteins, useful in the development of diagnostic kits or as vaccines.     

Application of Microneedle Arrays for Enhancement of Transdermal Permeation of Insulin: <Emphasis Type="Italic">In Vitro</Emphasis> Experiments,Scaling Analyses and Numerical Simulations

The aim of this investigation is to study the effect of donor concentration and microneedle (MN) length on permeation of insulin and further evaluating the data using scaling analyses and numerical simulations. Histological evaluation of skin sections was carried to evaluate the skin disruption and depth of penetration by MNs. Scaling analyses were done using dimensionless parameters like concentration of drug (C _t/C _s), thickness (h/L) and surface area of the skin (S _a/L ²). Simulation studies were carried out using MATLAB and COMSOL software to simulate the insulin permeation using histological sections of MN-treated skin and experimental parameters like passive diffusion coefficient. A 1.6-fold increase in transdermal flux and 1.9-fold decrease in lag time values were observed with 1.5 mm MN when compared with passive studies. Good correlation (R ²?>?0.99) was observed between different parameters using scaling analyses. Also, the in vitro and simulated permeations profiles were found to be similar (f ₂?≥?50). Insulin permeation significantly increased with increase in donor concentration and MN length (p?<?0.05). The developed scaling correlations and numerical simulations were found to be accurate and would help researchers to predict the permeation of insulin with new dimensions of MN in optimizing insulin delivery. Overall, it can be inferred that the application of MNs can significantly enhance insulin permeation and may be an efficient alternative for injectable insulin therapy in humans.     

Morphactin influences guggulsterone production in callus cultures of <Emphasis Type="Italic">Commiphora wightii</Emphasis>

Guggulsterone, a hypolipidemic natural agent, is produced in resin canals of the plant Commiphora wightii. In this study, the efficacy of different plant growth regulators was evaluated for optimizing its production. Morphactin was found to be effective in enhancing the accumulation of guggulsterones in callus cultures. Maximum callus growth was recorded on medium containing morphactin (0.1 mg l⁻¹) and 2iP (2.5 mg l⁻¹), whereas maximum guggulsterone production occurred when the calluses were cultured on medium containing 0.1 mg l⁻¹ morphactin and 1.0 mg l⁻¹ 2iP. Morphactin and 2iP interacted significantly to enhance the callus growth and guggulsterone production by about 8-folds in one-year-old cultures. However, the effect of morphactin on callus growth and guggulsterone production was not uniform over the levels of 2iP tested. Such an effect of morphactin has never been reported on the production of secondary metabolites.     

Global patterns in lake ecosystem responses to warming based on the temperature dependence of metabolism

Climate warming is expected to have large effects on ecosystems in part due to the temperature dependence of metabolism. The responses of metabolic rates to climate warming may be greatest in the tropics and at low elevations because mean temperatures are warmer there and metabolic rates respond exponentially to temperature (with exponents >1). However, if warming rates are sufficiently fast in higher latitude/elevation lakes, metabolic rate responses to warming may still be greater there even though metabolic rates respond exponentially to temperature. Thus, a wide range of global patterns in the magnitude of metabolic rate responses to warming could emerge depending on global patterns of temperature and warming rates. Here we use the Boltzmann–Arrhenius equation, published estimates of activation energy, and time series of temperature from 271 lakes to estimate long‐term (1970–2010) changes in 64 metabolic processes in lakes. The estimated responses of metabolic processes to warming were usually greatest in tropical/low‐elevation lakes even though surface temperatures in higher latitude/elevation lakes are warming faster. However, when the thermal sensitivity of a metabolic process is especially weak, higher latitude/elevation lakes had larger responses to warming in parallel with warming rates. Our results show that the sensitivity of a given response to temperature (as described by its activation energy) provides a simple heuristic for predicting whether tropical/low‐elevation lakes will have larger or smaller metabolic responses to warming than higher latitude/elevation lakes. Overall, we conclude that the direct metabolic consequences of lake warming are likely to be felt most strongly at low latitudes and low elevations where metabolism‐linked ecosystem services may be most affected.