Anil Thakur - Academia.edu (original) (raw)

Papers by Anil Thakur

Sri Lankan Journal of Anaesthesiology, 2012

Yeast Biotechnology: Diversity and Applications, 2009

Contents 13.1 Introduction ......................................................................... more Contents 13.1 Introduction .................................................................................................................... 260 13.2 Uses of Glutathione and Glutathione Analogues ........................................................... 261 13.3 Glutathione Biosynthesis .......... ... ... T. Satyanarayana, G. Kunze (eds.), Yeast ...

Yeast, 2013

Pgt1p encodes a glutathione transporter in Schizosaccharomyces pombe, orthologous to the Saccharo... more Pgt1p encodes a glutathione transporter in Schizosaccharomyces pombe, orthologous to the Saccharomyces cerevisiae glutathione transporter, Hgt1p. Despite high similarity to Hgt1p, Pgt1p failed to display functionality during heterologous expression in S. cerevisiae. In the present study we employed a genetic strategy to investigate the reason behind the non-functionality of pgt1⁺ in S. cerevisiae. Functional mutants were isolated after in vitro mutagenesis. Several mutants were obtained and four mutants analysed. Among these, three yielded different point mutations in the N-terminal region (301-350 bp) of the transporter before the first transmembrane domain, while one mutant contained a deletion of 42 nucleotides within the same region. The mutant pgt1⁺ proteins not only expressed and localized correctly, but displayed high-affinity glutathione transport capabilities in S. cerevisae. Comparison of wild-type pgt1⁺ with the functional mutants revealed that a loss in protein expression was responsible for lack of functionality of wild-type pgt1⁺ in S. cerevisiae. The mRNA levels in wild-type and mutants were comparable, suggesting that the block was in translation. The formation of a strong stem-loop structure appeared to be responsible for inefficient translation in pgt1⁺ and disruption of these structures in the mutants was probably permitting translation. This was confirmed by making silent mutations in this region of wild-type pgt1⁺, which led to their functionality in S. cerevisiae. This genetic strategy to relieve functional blocks in expression should greatly facilitate the study of these and other transporters from more intractable genetic organisms in a heterologous expression system.

Solar Energy Materials and Solar Cells, 2011

In this article, we have studied the temperature and illumination dependence of open-circuit volt... more In this article, we have studied the temperature and illumination dependence of open-circuit voltage (V OC ) in polymer-fullerene based solar cells. It has been observed that V OC at higher illumination intensities gets converged at 0 K which gives information about maximum achievable V OC in a particular donor-acceptor blend. Besides this, recombination processes have been studied by transient open-circuit voltage decay (TOCVD) and the transition between recombination regimes has been observed for the first time. At low V OC carrier lifetime exhibits a constant value around 500 ms, which is interpreted in terms of a monomolecular recombination regime. At higher V OC carrier lifetime decreases as derived from a bimolecular relaxation law. The method allows estimating the recombination coefficient, which results in 2 Â 10 À 13 cm 3 s À 1 . The results have been explained by considering Gaussian density-of-states (DOS) for highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO).

Pramana, 2005

The study of electrical resistivity of compound-forming liquid alloy, NaPb, is presented as a fun... more The study of electrical resistivity of compound-forming liquid alloy, NaPb, is presented as a function of concentration. Hard sphere diameters of Na and Pb are obtained through the interionic pair potentials evaluated using Troullier and Martins ab initio pseudopotential, which have been used to calculate the partial structure factors S(q). Considering the liquid alloy to be a ternary mixture, Ziman formula, modified for complex formation has been used for calculating resistivity of binary liquid alloys. Form factors are calculated using ab initio pseudopotentials. The results suggest that Ziman formalism, when used with ab initio pseudopotentials, are quite successful in explaining the electrical resistivity data of compound-forming binary liquid alloys.

Physica B: Condensed Matter, 2006

The electrical resistivity of the compound forming liquid alloy NaSn is studied as a function of ... more The electrical resistivity of the compound forming liquid alloy NaSn is studied as a function of concentration. Hard-sphere diameters of Na and Sn are obtained through the inter-ionic pair potentials evaluated using Troullier and Martins ab initio pseudopotential, which have been used to calculate partial structure factors SðqÞ. Considering the liquid alloy to be a ternary mixture, Ziman's formula for calculating the resistivity of binary liquid alloys, modified for complex formation, has been used. Form factors are calculated using ab initio pseudopotentials. The results suggest that the Ziman formalism, when used with ab initio pseudopotentials, is quite successful in explaining the electrical resistivity data of compound forming binary liquid alloys. r

Organic Electronics, 2008

The qualitative nature of the interface of poly (3-hexylthiophene) (P3HT) with Aluminum (Al) and ... more The qualitative nature of the interface of poly (3-hexylthiophene) (P3HT) with Aluminum (Al) and LiF modified Aluminum (LiF:Al) has been studied using photoluminescence (PL) spectra. It was observed that coating Al on pristine P3HT film resulted in an increase in the degree of intrachain disorder. Also, a blue shift in the peak PL intensity was observed. These observations have been explained on the basis of intrachain disorder induced by the deposition of Al via thermal evaporation on P3HT film. Furthermore, bias dependence of PL spectra for ITO/P3HT/Al and ITO/P3HT/LiF:Al type Schottky cells were studied. Under the reverse bias conditions, PL quenching was found to relate directly to the depletion layer width. The increase in depletion width was found to be higher in the Al cell as compared to that of the LiF:Al cell. However, the photocurrents were higher in LiF:Al coated cells. These observed results have been explained on the basis of the difference in their respective band alignment.

Journal of Molecular Liquids, 2014

ABSTRACT

Journal of Applied Physics, 2005

Memory effect in smectic-A phase of ferroelectric liquid crystal. [Journal of Applied Physics 97,... more Memory effect in smectic-A phase of ferroelectric liquid crystal. [Journal of Applied Physics 97, 084106 (2005)]. Anil K. Thakur, Sukhwant S. Bawa, Ashok M. Biradar, Sarabjot Kaur, S. Annapoorni. Abstract. Memory effect has been ...

Journal of Applied Physics, 2012

Japanese Journal of Applied Physics, 2005

The dielectric relaxation processes near the transition temperature (Tc) of Sm C*-Sm A phase tran... more The dielectric relaxation processes near the transition temperature (Tc) of Sm C*-Sm A phase transition in an electroclinic liquid crystal have been investigated in a homogeneously aligned cell of 2.5 mum thickness in the frequency range of 50 Hz to 10 MHz. No abrupt change in phase during the Sm C*-Sm A phase transition has been detected by the dielectic

$Research paper thumbnail of Comparative evaluation of subclavian vein catheterisation using supraclavicular versus infraclavicular approach$

Indian Journal of Anaesthesia, 2014

Infraclavicular (IC) approach of subclavian vein (SCV) catheterisation is widely used as compared... more Infraclavicular (IC) approach of subclavian vein (SCV) catheterisation is widely used as compared to supraclavicular (SC) approach. The aim of the study was to compare the ease of catheterisation of SCV using SC versus IC approach and also record the incidence of complications related to either approach, if any. In the study, 60 patients enrolled were randomly divided into two groups of 30 patients each. In Gp. SC right SCV catheterisation was performed using SC approach and in Gp. IC catheterisation was performed using IC approach. Access time, success rate of cannulation, number of attempts to cannulate vein, ease of guidewire and catheter insertion and length of catheter inserted and any associated complications were recorded. The mean access time in group SC for SCV catheterisation was 4.30 ± 1.02 min compared to 6.07 ± 2.14 min in group IC. The overall success rate in catheterisation of the right SCV using SC approach (29 out of 30) was better as compared with group IC (27 out of 30) using IC approach. First attempt success in the SC group was 75.6% as compared with 59.25% in the IC group. All successful subclavian vein catheterisations in SC group and IC group were associated with smooth insertion of guidewire following subclavian venipuncture. The SC approach of SCV catheterisation is comparable to IC approach in terms of landmarks accessibility, success rate and rate of complications.

FEMS Yeast Research, 2008

The Schizosaccharomyces pombe ORF, SPAC29B12.10c, a predicted member of the oligopeptide transpor... more The Schizosaccharomyces pombe ORF, SPAC29B12.10c, a predicted member of the oligopeptide transporter (OPT) family, was identified as a gene encoding the S. pombe glutathione transporter (Pgt1) by a genetic strategy that exploited the requirement of the cys1aD strain of S. pombe (which is defective in cysteine biosynthesis) for either cysteine or glutathione, for growth. Disruption of the ORF in the cys1aD strain led to an inability to grow on glutathione as a source of cysteine. Cloning and subsequent biochemical characterization of the ORF revealed that a high-affinity transporter for glutathione (K m = 63 mM) that was found to be localized to the plasma membrane. The transporter was specific for glutathione, as significant inhibition in glutathione uptake could be observed only by either reduced or oxidized glutathione, or glutathione conjugates, but not by dipeptides or tripeptides. Furthermore, although glu-cys-gly, an analogue of glutathione (g-glu-cys-gly), could be utilized as a sulphur source, the growth was not Pgt1 dependent. This further underlined the specificity of this transporter for glutathione. The strong repression of pgt1 1 expression by cysteine suggested a role in scavenging glutathione from the extracellular environment for the maintenance of sulphur homeostasis in this yeast. FEMS Yeast Res 8 (2008) 916-929

Chinese Physics Letters, 2005

... 22， No. 10 (2005) 2611 Electrical Resistivity of NaK Binary Liquid Alloy Using Ab-Initio Pse... more ... 22， No. 10 (2005) 2611 Electrical Resistivity of NaK Binary Liquid Alloy Using Ab-Initio Pseudopotentials Anil Thakur*, PK Ahluwalia Department of Physics, Himachal Pradesh University, Shimla-171005, India (Received 8 March 2005) ... Page 3. 2612 Anil Thakur et al. Vol. 22 ...

Biochemical Journal, 2010

Hgt1p, a high-affinity glutathione transporter from Saccharomyces cerevisiae belongs to the recen... more Hgt1p, a high-affinity glutathione transporter from Saccharomyces cerevisiae belongs to the recently described family of OPTs (oligopeptide transporters), the majority of whose members still have unknown substrate specificity. To obtain insights into substrate recognition and translocation, we have subjected all 21 residues of TMD9 (transmembrane domain 9) to alanine-scanning mutagenesis. Phe523 was found to be critical for glutathione recognition, since F523A mutants showed a 4-fold increase in Km without affecting expression or localization. Phe523 and the previously identified polar residue Gln526 were on the same face of the helix suggesting a joint participation in glutathione recognition, whereas two other polar residues, Ser519 and Asn522, of TMD9, although also orientated on the same face, did not appear to be involved. The size and hydrophobicity of Phe523 were both key features of its functionality, as seen from mutational analysis. Sequence alignments revealed that Phe523 and Gln526 were conserved in a cluster of OPT homologues from different fungi. A second cluster contained isoleucine and glutamate residues in place of phenylalanine and glutamine residues, residues that are best tolerated in Hgt1p for glutathione transporter activity, when introduced together. The critical nature of the residues at these positions in TMD9 for substrate recognition was exploited to assign substrate specificities of several putative fungal orthologues present in these and other clusters. The presence of either phenylalanine and glutamine or isoleucine and glutamate residues at these positions correlated with their function as high-affinity glutathione transporters based on genetic assays and the Km of these transporters towards glutathione.