Papers by Akhilesh Pandey
Journal of Biological Chemistry, 2002
Phosphorylation is one of the most common forms of protein modification. The most frequent target... more Phosphorylation is one of the most common forms of protein modification. The most frequent targets for protein phosphorylation in eukaryotes are serine and threonine residues, although tyrosine residues also undergo phosphorylation. Many of the currently applied methods for the detection and localization of protein phosphorylation sites are mass spectrometry-based and are biased against the analysis of tyrosine-phosphorylated residues because of the stability and low reactivity of phosphotyrosines. To overcome this lack of sensitive methods for the detection of phosphotyrosine-containing peptides, we have recently developed a method that is not affected by the more predominant threonine or serine phosphorylation within cells. It is based on the specific detection of immonium ion of phosphotyrosine at 216.043 Da and does not require prior knowledge of the protein sequence. In this report, we describe the first application of this new method in a proteomic strategy. Using anti-phosphotyrosine antibodies for immunoprecipitation and one-dimensional gel electrophoresis, we have identified 10 proteins in the epidermal growth factor receptor signaling pathway, of which 8 have been shown previously to be involved in epidermal growth factor signaling. Most importantly, in addition to several known tyrosine phosphorylation sites, we have identified five novel sites on SHIP-2, Hrs, Cbl, STAM, and STAM2, most of which were not predicted to be phosphorylated. Because of its sensitivity and selectivity, this approach will be useful in proteomic approaches to study tyrosine phosphorylation in a number of signal transduction pathways.
Journal of Biological Chemistry, 2002
A novel family of cysteine-rich secreted proteins with unique tissue distribution has recently be... more A novel family of cysteine-rich secreted proteins with unique tissue distribution has recently been identified. One of the members, resistin (for "resistance to insulin"), also called FIZZ3, was identified in a screen for molecules that are down-regulated in mature adipocytes upon administration of thiazolidinediones. The prototypical member of this family was originally identified from bronchoalveolar lavage fluid of inflamed lungs and designated FIZZ1 ("found in inflammatory zone"). This molecule was also found to be highly expressed in adipose tissue and was named resistin-like molecule ␣ (RELM␣). Here we demonstrate that RELM␣ inhibits the differentiation of 3T3-L1 preadipocytes into adipocytes. RELM␣ has no effect on proliferation of 3T3-L1 preadipocytes. Pretreatment of 3T3-L1 preadipocytes with RELM␣ does not affect insulin-or plateletderived growth factor-induced mitogenesis. IRS-1 phosphorylation and glucose transport stimulated by insulin in mature adipocytes were also unaffected by RELM␣. We show that RELM␣ forms disulfide-linked homooligomers based on results from electrophoresis under reducing and nonreducing conditions, coimmunoprecipitation experiments as well as by mass spectrometry. In addition, RELM␣ is able to form heterooligomers with resistin but not RELM. Since RELM␣ is expressed by adipose tissue and it is a secreted factor, our findings suggest that RELM␣ may be involved in the control of the adipogenesis as well as in the process of muscle differentiation.
Detection of Tyrosine Phosphorylated Peptides by Precursor Ion Scanning Quadrupole TOF Mass Spectrometry in Positive Ion Mode
Analytical Chemistry, 2001
Phosphorylation is a common form of protein modification. To understand its biological role, the ... more Phosphorylation is a common form of protein modification. To understand its biological role, the site of phosphorylation has to be determined. Generally, only limited amounts of phosphorylated proteins are present in a cell, thus demanding highly sensitive procedures for phosphorylation site determination. Here, a novel method is introduced which enables the localization of tyrosine phosphorylation in gel-separated proteins in the femtomol range. The method utilizes the immonium ion of phosphotyrosine at m/z 216.043 for positive ion mode precursor ion scanning combined with the recently introduced Q2-pulsing function on quadrupole TOF mass spectrometers. The high resolving power of the quadrupole TOF instrument enables the selective detection of phosphotyrosine immonium ions without interference from other peptide fragments of the same nominal mass. Performing precursor ion scans in the positive ion mode facilitates sequencing, because there is a no need for polarity switching or changing pH of the spraying solvent. Similar limits of detection were obtained in this approach when compared to triple-quadrupole mass spectrometers but with significantly better selectivity, owing to the high accuracy of the fragment ion selection. Synthetic phosphopeptides could be detected at 1 fmol/microL, and 100 fmol of a tyrosine phosphorylated protein in gel was sufficient for the detection of the phosphorylated peptide in the unseparated digestion mixture and for unambiguous phosphorylation site determination. The new method can be applied to unknown protein samples, because the identification and localization of the modification is performed on the same sample.
We present the results obtained through new optical broad-band (BV(RI)c) polarimetric observation... more We present the results obtained through new optical broad-band (BV(RI)c) polarimetric observations carried out towards NGC 1893. In this study we found at least two foreground dust layers present towards NGC 1893. One at 170 pc and another at 350 pc. Second dust layer was found to be mainly responsible for the observed polarization towards the cluster. The polarization efficiency
Treatment of visceral leishmaniasis with injectable paromomycin (aminosidine). An open-label randomized phase-II clinical study
Transactions of the Royal Society of Tropical Medicine and Hygiene
A prospective randomized, comparative, open-label trial of the safety and efficacy of paromomycin (aminosidine) plus sodium stibogluconate versus sodium stibogluconate alone for the treatment of visceral leishmaniasis
Transactions of the Royal Society of Tropical Medicine and Hygiene
Response to treatment with organic pentavalent antimonials, the standard first-line treatment for... more Response to treatment with organic pentavalent antimonials, the standard first-line treatment for visceral leishmaniasis (VL), has been decreasing since their introduction into India. Combining sodium stibogluconate (SB) with paromomycin (PM) may be an efficient alternative to single-agent therapy. This trial was designed to assess the safety and efficacy of PM 12 or 18 mg/kg daily plus SB 20 mg/kg daily for 21 days compared to SB alone for 30 days. One hundred and fifty patients were randomly assigned in 1996 to 1 of the 3 treatments and followed-up for 180 days. At the end of treatment, 49 of 52 patients receiving PM12 + SB, 46 of 48 receiving PM18 + SB, and 27 of 49 patients receiving SB alone, were cured. During follow-up there was 1 relapse in each of the treatment groups, giving final cure rates of 48 of 52 (92.3%) for PM12 + SB, 45 of 48 (93.8%) for PM18 + SB, and 26 of 49 (53.1%) for SB. PM plus SB for 21 days at either 12 or 18 mg/kg daily was significantly more effective t...
Efficacy of amphotericin B in multi-drug resistant kala-azar in children in first decade of life
Indian journal of pediatrics
Fifty children in the first decade of life, and suffering from multiple drug resistant kala-azar,... more Fifty children in the first decade of life, and suffering from multiple drug resistant kala-azar, confirmed by demonstration of amastigotes in aspirates of bone marrow or spleen were treated with amphotericin B in gradually increasing dosage to a total dose of 20 mg/kg. All patients had classical features of severe kala-azar, and had taken more than one course of antimony and pentamidine, and three patients had taken one additional course of ketoconazole besides many courses of antimony and pentamidine. The clinical response started just after first infusion in 8 patients, and the patients became afebrile. By 5th infusion, all looked better and 18 patients became afebrile. By 15th infusion all patients were afebrile and cheerful. Their spleens became smaller and body weights and total white cell counts increased. Forty eight patients had parasitological cure at the end of treatment, and only 2 patients required an additional 5 infusions for parasitological cure. All patients were ul...
Optical Materials, 2010
Congruent lithium niobate single crystal with titanium ion dopant (2 and 5 mol%) has been success... more Congruent lithium niobate single crystal with titanium ion dopant (2 and 5 mol%) has been successfully grown in an air by Czochralski technique with Automatic Diameter Control facility. The results of analysis of the influence of the Ti dopant concentration on X-ray diffraction, refractive index, optical absorption edge and FTIR in lithium niobate single crystals were presented. High Resolution X-ray Diffraction technique was used to study the crystalline quality through full width half maximum values with the presence of dopant incorporation. The increase of refractive index values observed for doped samples than pure sample by prism coupling technique with different laser sources. The position of the fundamental absorption edge in the near UV region was analyzed by UV-Vis spectra. FTIR spectra revealed that 5 mol% Ti doped lithium niobate crystals clearly suppresses the OH À defect sites than 2 mol% which indicates the limited influence of the humidity. The reason for OH À defect site suppression is discussed. Also the obtained results from all measurements are compared with pure congruent lithium niobate crystal.
Complexation studies with 90Y from a novel 90Sr-90Y generator
Radiochimica Acta, 2001
ABSTRACT
Star formation in young open cluster NGC 1893
We have carried out a multi-wavelength study of the star forming region NGC 1893 to make a compre... more We have carried out a multi-wavelength study of the star forming region NGC 1893 to make a comprehensive exploration of the effects of massive stars on low mass star formation. Using our deep optical B, V, R, I broad band and Halpha narrow band photometry and slitless spectroscopy along with archival data from the surveys such as 2MASS, MSX, IRAS
. Gamma-ray bursts (GRBs) are thought to result from the interaction of an extremely relativistic... more . Gamma-ray bursts (GRBs) are thought to result from the interaction of an extremely relativistic outflow interacting with a small amount of material surrounding the site of the explosion. Multi-wavelength observations covering the γ-ray to radio wavebands allow investigations of this 'fireball' model. On 23 January 1999 optical emission was detected while the γ-ray burst was still underway. Here we report the results of γ-ray, optical/infra-red, sub-mm, mm and radio observations of this burst and its afterglow, which indicate that the prompt and afterglow emissions from GRB 990123 are associated with three distinct regions in the fireball. The afterglow one day after the burst has a much lower peak frequency than those of previous bursts; this explains the short-lived nature of the radio emission, which is not expected to reappear. We suggest that such differences reflect variations in the magnetic-field strengths in the afterglow emitting regions.
Effect of Shear Rate and Nanoclay Content on the Die Swell of Polypropylene Nanocomposites Extruded Under Capillary Flow
Die swell is an important parameter of polymeric materials during extrusion. It plays a significa... more Die swell is an important parameter of polymeric materials during extrusion. It plays a significant role in governing the final dimensions of the extrudate and hence is of utmost importance for die design and process control during extrusion. In present study, effect of shear rate and nanoclay content on die swell behavior during extrusion of polypropylene clay nanocomposites with different
Papers from the 12th Canadian Semiconductor Technology Conference-Organic Materials and Devices-Molecular model T6: C60 bulk-heterojunction solar cells
Journal of Plant Protection Research, 2008
Herbicidal potential of CFCF (Cell free culture filtrate) of Sclerotium rolfsii against Partheniu... more Herbicidal potential of CFCF (Cell free culture filtrate) of Sclerotium rolfsii against Parthenium hysterophorus was determined by shoot cut, seedling and detached leaf bioassays. Maximum phytotoxicity was obtained from 14 day's old fermented broth with sucrose + 0.5% Tween 20 as formulating agent. Significant reduction in chlorophyll and protein contents of host was also noticed.
Non-Gaussian random-matrix ensembles with banded spectra
Physical Review E, 2003
Non-Gaussian random-matrix ensembles are important in many applications. We propose Monte Carlo a... more Non-Gaussian random-matrix ensembles are important in many applications. We propose Monte Carlo and Langevin methods for generating non-Gaussian ensembles and their eigenvalue spectra. We also provide a general framework for analytic studies of the level density in these ensembles. We show that, in general, the level densities exhibit banded spectra, with important implications for mesoscopic systems and complex nuclei. The universality of energy-level fluctuations is confirmed.
In Brief
Trends in Genetics, 2002
In Brief
Trends in Genetics, 2002
In Brief
Trends in Genetics, 2002
In Brief
Trends in Genetics, 2002
In Brief
Trends in Genetics, 2002
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Papers by Akhilesh Pandey