Jrs Sevenfoldism | Madan Mohan Malaviya University of Technology, Gorakhpur (original) (raw)

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Papers by Jrs Sevenfoldism

Electrochimica Acta, 2008

A new surface-enhanced Raman scattering (SERS)-active silver substrate has been developed by usin... more A new surface-enhanced Raman scattering (SERS)-active silver substrate has been developed by using a combination of electrochemical triangular-wave oxidation/reduction cycles (ORCs) and argon plasma treatment to roughen the substrate, increasing its SERS effect. In the first step, a mechanically polished Ag substrate was roughened through triangular-wave ORCs in an aqueous solution containing 0.1M KCl. Next, the electrochemically roughened Ag substrate

Structure, 1999

Background: The EF-hand family is a large set of Ca2+-binding proteins that contain characteristi... more Background: The EF-hand family is a large set of Ca2+-binding proteins that contain characteristic helix-loop-helix binding motifs that are highly conserved in sequence. Members of this family include parvalbumin and many prominent regulatory proteins such as calmodulin and troponin C. EF-hand proteins are involved in a variety of physiological processes including cell-cycle regulation, second messenger production, muscle contraction, microtubule organization and vision.Results: We have determined the structures of parvalbumin mutants designed to explore the role of the last coordinating residue of the Ca2+-binding loop. An E101D substitution has been made in the parvalbumin EF site. The substitution decreases the Ca2+-binding affinity 100-fold and increases the Mg2+-binding affinity 10-fold. Both the Ca2+- and Mg2+-bound structures have been determined, and a structural basis has been proposed for the metal-ion-binding properties.Conclusions: The E101D mutation does not affect the Mg2+ coordination geometry of the binding loop, but it does pull the F helix 1.1 Å towards the loop. The E101D–Ca2+ structure reveals that this mutant cannot obtain the sevenfold coordination preferred by Ca2+, presumably because of strain limits imposed by tertiary structure. Analysis of these results relative to previously reported structural information supports a model wherein the characteristics of the last coordinating residue and the plasticity of the Ca2+-binding loop delimit the allowable geometries for the coordinating sphere.

Physics and Chemistry of Minerals, 1983

Synchrotron radiation has been used to collect high-resolution Fe K absorption near-edge spectra ... more Synchrotron radiation has been used to collect high-resolution Fe K absorption near-edge spectra of a suite of Fe minerals and compounds having a range of Fe environments. These spectra, along with those of previous workers, indicate that the number, position, and intensity of near-edge features are characteristic of Fe valence and general site geometry. For example, the crest of the K-edge for Fe2+ in a six-coordinated site in the oxides studied is about 3 eV lower in energy than that for Fe3+ in a similar site. The K-edge crest for Fe3+ in a four-coordinated site is 1 to 2 eV lower than for Fe3+ in a regular site. The shape of the edge crest is sensitive to the details of first-neighbor bonding distances, tending to be broader in species with irregular Fe sites and varying in energy according to the average bond length. Comparison with Ca2+ and Zn2+ spectra from the literature is made and the applicability and utility of edge measurements discussed.

Environmental Science & Technology, 1976

~ w Toxic effects of molecular hydrogen sulfide to eggs, fry, and juveniles of the fathead minnow... more ~ w Toxic effects of molecular hydrogen sulfide to eggs, fry, and juveniles of the fathead minnow, Pimephales promelas Rafinesque, were determined in flow-through bioassays. The 96-h LC50 of laboratory-cultured juveniles a t 20 "C was 0.0243 mg/l. H2S. Fry were approximately twice as senskive. Response with temperature in wild stock juveniles varied from a 96-h LC50 of 0.7754 mg/l. a t 6.5 "C to 0.0423 mg/l. H2S a t 25 "C. In chronic exposure to H2S from egg through two generations of laboratory-cultured stock in flow-through bioassays, adverse effects on growth, survival, and fecundity occurred above 0.004 mg/l. H2S. Chronic exposure of wild stock up to 346 days caused adverse effects on growth and survival above 0.008 mg/l. H2S. At comparable temperatures apparent safe levels with long exposure were five-to sevenfold lower than the 96-h LC50 for both stocks.

Journal of Bacteriology, 2001

The hyperthermophilic archaeon Pyrococcus furiosus grows optimally at 100°C by the fermentation o... more The hyperthermophilic archaeon Pyrococcus furiosus grows optimally at 100°C by the fermentation of peptides and carbohydrates. Growth of the organism was examined in media containing either maltose, peptides (hydrolyzed casein), or both as the carbon source(s), each with and without elemental sulfur (S 0 ). Growth rates were highest on media containing peptides and S 0 , with or without maltose. Growth did not occur on the peptide medium without S 0 . S 0 had no effect on growth rates in the maltose medium in the absence of peptides. Phenylacetate production rates (from phenylalanine fermentation) from cells grown in the peptide medium containing S 0 with or without maltose were the same, suggesting that S 0 is required for peptide utilization. The activities of 14 of 21 enzymes involved in or related to the fermentation pathways of P. furiosus were shown to be regulated under the five different growth conditions studied. The presence of S 0 in the growth media resulted in decreases in specific activities of two cytoplasmic hydrogenases (I and II) and of a membrane-bound hydrogenase, each by an order of magnitude. The primary S 0 -reducing enzyme in this organism and the mechanism of the S 0 dependence of peptide metabolism are not known. This study provides the first evidence for a highly regulated fermentation-based metabolism in P. furiosus and a significant regulatory role for elemental sulfur or its metabolites.

Journal of Virology, 2004

Several latent proteins have profound effects on cellular growth, including activation of NF-B, p... more Several latent proteins have profound effects on cellular growth, including activation of NF-B, phosphatidylinositol 3-OH kinase (PI3K) signaling, and notch signaling. Activation of PI3K can affect the activity of ␤-catenin, the target of the wnt signaling pathway. Deregulation of ␤-catenin is associated with a number of malignancies. To determine if ␤-catenin is regulated by EBV infection, EBV-infected cells were examined for ␤-catenin levels and localization. ␤-Catenin was increased in EBV-positive tumor cell lines compared to EBV-negative lines, in EBV-infected Burkitt's lymphoma cell lines, and in EBV-transformed lymphoblastoid cell lines (LCL). In contrast to wnt signaling, EBV consistently induced the accumulation of ␤-catenin in the cytoplasm but not the nucleus. The ␤-catenin regulating kinase, glycogen synthase kinase 3␤ (GSK3␤), was shown to be phosphorylated and inactivated in EBV-infected lymphocytes. Inactivated GSK3␤ was localized to the nucleus of EBV-infected LCL. Neither the cytoplasmic accumulation of ␤-catenin nor the nuclear inactivation of GSK3␤ was affected by the inhibition of PI3K signaling. These data indicate that latent infection with EBV has unique effects on ␤-catenin signaling that are distinct from activation of wnt and independent of its effects on PI3K.

Journal of Allergy and Clinical Immunology, 1996

It has been suggested that the differential histamine-releasing activity of an IgE-dependent hist... more It has been suggested that the differential histamine-releasing activity of an IgE-dependent histamine-releasing factor (HRF), which has recently been cloned, is related to carbohydrate differences in the IgE molecule. Lectins are able to recognize specific glycoforms and might therefore be useful in characterizing the proposed heterogeneity of IgE molecules. As one test of this hypothesis, we examined the histamine release potency of several well-characterized lectins on basophils passively sensitized with serum containing IgE molecules that support HRF-induced histamine release (IgE +) or serum that does not support release by this stimulus (IgE-). Histamine release was induced by challenging basophils with different concentrations of concanavalin A, Lens culinaris (LcH), and Pisum sativum (PSA). Doseresponse curves revealed that LcH caused 30% histamine release at 2 txg/ml with IgE + sensitized cells, whereas the same release with IgE cells required sixfold higher concentrations. Similar values for PSA showed a sevenfold difference. With concanavalin A, the

We investigated the influence of size and lipid composition on the pharmacokinetic behavior of li... more We investigated the influence of size and lipid composition on the pharmacokinetic behavior of liposomes and their contents in the rabbit eye. Small and large unilamellar vesicles (SUV and LUV), prepared with and without cholesterol in the membrane, were injected intravitreally in rabbits. The vesicles were labelled with 125I and contained 51Cr-EDTA in the aqueous compartment. The mode of elimination of the vesicles from the vitreous humor is uncertain but may be via the anterior route; 51Cr-EDTA, like gentamicin, probably is eliminated by the anterior route. The rate of clearance of the lipid label appeared to be related to the size but not to the cholesterol content of the liposomes. Liposome-encapsulation prolonged the half-life of 51Cr-EDTA by up to 11-fold in the vitreous humor of normal eyes. The prolongation was greatest with cholesterol-containing vesicles, presumably because these are most stable, and was somewhat greater with large than with small vesicles. For SUV and LUV, the rate of elimination of 51Cr-EDTA from the normal eye was determined mainly by the rate of leakage from the liposomes, whereas for SUV-cholesterol and LUV-cholesterol, it was determined mainly by the rate of clearance of the liposomes themselves. Both 51Cr-EDTA and liposomes (125I label) had a shorter half-life in infected than in normal eyes. Encapsulation of 51Cr-EDTA prolonged its half-life by up to sevenfold in infected eyes; the effect was greatest with cholesterol-containing vesicles. These results suggest that both the structure of the liposome and the state of the eye may markedly affect the pharmacokinetic behavior of intravitreal liposomes.