CSIR - Central Electrochemical Research Institute

Chennai, India

CSIR - Central Electrochemical Research Institute

Chennai, India

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Prathap G.,CSIR - Central Electrochemical Research Institute
Journal of the American Society for Information Science and Technology | Year: 2014

The h-index, as originally proposed (Hirsch, 2005), is a purely heuristic construction. Burrell (2013) showed that efforts to derive formulae from the mathematical framework of Lotkaian informetrics could lead to misleading results. On this note, we argue that a simple heuristic " thermodynamical" model can enable a better three-dimensional (3D) evaluation of the information production process leading to what we call the zynergy-index. © 2013 ASIS&T.

Singh R.,CSIR - Central Electrochemical Research Institute | Saini N.,CSIR - Central Electrochemical Research Institute
Journal of Cell Science | Year: 2012

A number of anti-cancer strategies aim to target the mitochondrial apoptotic machinery to induce tumour cell death. Mitochondria play a key role as death amplifiers by releasing apoptogenic factors from the mitochondrial inter-membrane space into the cytosol. BCL2 proteins are known for their ability to regulate both mitochondrial physiology and cell death, and their deregulated expression often renders cancer cells insensitive to apoptosis-inducing anticancer drugs. Recently, a few microRNAs, a novel class of gene regulators, have been demonstrated to regulate expression of some members of the BCL2 family. Here, we have combined computational and experimental approaches to identify miRNAs that can regulate the anti-apoptotic protein BCL2. We report that miR-195, miR-24-2 and miR-365-2 act as negative regulators of BCL2 through direct binding to their respective binding sites in the 3'-UTR of the human BCL2 gene. Ectopic expression of miR-195, miR-24-2 and miR-365-2 individually led to a significant reduction of the levels of BCL2 protein. Additionally, we found that overexpression of these miRNAs induced dissipation of the mitochondrial membrane potential and release of cytochrome c from mitochondria into the cytosol. Furthermore, we demonstrated that overexpression of these miRNAs not only caused an increase in apoptosis but also augmented the apoptotic effect of etoposide in breast cancer MCF7 cells. These data not only show the apoptotic nature of miR-195, miR-24-2 and miR-365-2 but also highlight the therapeutic potential of these miRNAs. © 2012.

Kundu S.,CSIR - Central Electrochemical Research Institute
Journal of Materials Chemistry C | Year: 2013

A new route for the formation of shape-selective Au nanoparticles (NPs) has been demonstrated. The reduction of Au(iii) ions was done with alkaline 2,7-DHN in CTAB micellar media under 30 min of continuous UV-irradiation. The reaction results in uniform Au nanospheres and Au nanowires. With the change in Au(iii) ion to CTAB molar ratio, the particles' size and shape can be tuned. Au nanorods and nanoprisms are synthesized via seed mediated growth and microwave heating methods and the particles are characterized by several spectroscopic tools. The shape effects of the four different types of Au NPs were investigated using surface enhanced Raman scattering (SERS) studies. The results showed that the SERS intensity increases with the change in NPs' shape from nanospheres to nanorods to nanowires to nanoprisms. The highest enhancement observed for the nanoprisms is due to the presence of a maximum number of sharp edges or surface active rough surfaces compared to the smooth surfaces of the nanospheres. This high enhancement factor (EF) of these multiple shaped Au NPs might find potential application in detection of single molecules or in many other fields like detection of bio-molecules, bioassays, bio-diagnosis or even clinical diagnostics and in medical therapy. This journal is © 2013 The Royal Society of Chemistry.

Kundu S.,CSIR - Central Electrochemical Research Institute
Physical Chemistry Chemical Physics | Year: 2013

Self-assembled Ag NPs on DNA chains were synthesized using a simple photochemical technique. The size of the individual Ag NPs and their average diameter on the DNA chains can be tuned just by controlling the various reaction parameters. The average diameter of the self-assembled Ag NPs on DNA chains were varied in the 20-75 nm range, whereas the average diameters of the individual Ag NPs can be varied in the 5-15 nm range. The nominal length of the DNA chains self-assembled by Ag NPs can be extended to a few microns. The present process does not need any external reducing agent like sodium borohydride or hydrazine or others, and DNA itself can act in a dual role: a 'reducing agent' and a 'stabilizing agent' for the formation of DNA-Ag NPs colloidal dispersion. The synthesized DNA-Ag NPs were well characterized by UV-Vis, EDS, TEM, XRD, XPS, and FT-IR analyses. The self-assembled Ag NPs on DNA chains were found to have good catalytic activity towards the reduction of aromatic nitro compounds. The potentiality of the DNA-Ag NPs as catalyst was tested both in solution and after depositing over solid substrate as thin films. The synthesized Ag NPs on DNA were found to be extremely stable for a period of six months under ambient conditions while kept inside a refrigerator. This pronounced catalytic activity of the material might be useful for future applications in a variety of organic and inorganic catalysis reactions and in SERS-based detection of environmentally important bio-molecules and in sensors. © 2013 The Owner Societies.

Shinde D.B.,CSIR - National Chemical Laboratory | Pillai V.K.,CSIR - Central Electrochemical Research Institute
Angewandte Chemie - International Edition | Year: 2013

Quantum dots: A sequential, single-electron charging process of monodisperse graphene quantum dots (GQDs) encapsulated in a dodecylamine envelope, facilitating a capacitance of a few attofarads is reported. The average GQDs dimensions, as ascertained from high-resolution transmission electron microscopy and atomic force microscopy, of about 3±0.3, 2.6±0.2, and 2.2±0.3 nm control this unprecedented behavior (see picture). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rayasam G.V.,CSIR - Central Electrochemical Research Institute
Expert Opinion on Therapeutic Targets | Year: 2014

Introduction: Tuberculosis (TB) is still a leading cause of mortality in the developing world and there is an unmet clinical need for new drugs with novel mechanism of action. Targeting the complex and unique cell wall of TB-causing pathogen Mycobacterium tuberculosis (Mtb) has been a mainstay of TB drug discovery. Though, the composition of the cell wall of Mtb is well understood, little is known about the assembly process of the cell wall such as the transport of mycolic acids across the cell wall. Areas covered: Recent research demonstrating MmpL3 protein as a transmembrane transporter of mycolic acids is discussed. In addition, MmpL3 has also been implicated in heme transport. Research describing several diverse chemical inhibitors that inhibit MmpL3 is reviewed. Expert opinion: Evidence so far suggests MmpL3 is a transporter of mycolic acids. It has emerged as a novel therapeutic target for Mtb that is essential and for which several small molecule inhibitors have been identified. Identifying the interacting partners, understanding the substrate specificity and the mechanism of transport by MmpL3 are some of the gaps in knowledge that need to be addressed. © 2014 Informa UK, Ltd.

Adlakha Y.K.,CSIR - Central Electrochemical Research Institute
Cell death & disease | Year: 2013

Aberrant regulation of cholesterol homeostasis is associated with obesity as well as multiple types of cancer. However, the mechanism behind these is largely missing. Here, we show that microRNA (miRNA)-128-2 is not only a pro-apoptotic microRNA but it also alters the expression of genes involved in cellular cholesterol homeostasis. Cholesterol efflux via ATP-binding cassette transporters (ABCA1 and ABCG1) is a mechanism for cells to eliminate excess cholesterol and prevent cellular cholesterol accumulation. The regulation of these pathways is complex with transcriptional regulation by sterol-regulatory element-binding protein (SREBP) and liver X receptor/retinoid X receptor (RXR) transcription factors but poorly understood at the post-transcriptional levels. MiR-128-2 increases the expression of SREBP2 and decreases the expression of SREBP1 in HepG2, MCF7 and HEK293T cells independent of sirtuin 1 (SIRT1) status. MiR-128-2 inhibits the expression of ABCA1, ABCG1 and RXRα directly through a miR-128-2-binding site within their respective 3'untranslated regions. The administration of miR-128-2 leads to decline in the protein and mRNA levels of ABCA1, ABCG1 and RXRα. Conversely, anti-miRNA treatment leads to increased ABCA1, ABCG1 and RXRα expression. The inverse correlation between miR-128-2 and its targets viz. ABCA1 and ABCG1 was also established during high-fat diet in different mice tissues. Our data show that cholesterol efflux is attenuated by miR-128-2 overexpression and, conversely, stimulated by miR-128-2 silencing. Further, we also observed the induction of ER stress response by miR-128-2. In this study, we provide the first evidence of miR-128-2 to be a new regulator of cholesterol homeostasis. Our study shows dual role of miR-128-2, as a pro-apoptotic molecule as well as a regulator of cholesterol homeostasis.

Sharma A.,CSIR - Central Electrochemical Research Institute
Trends in Molecular Medicine | Year: 2015

In his article, Szyf [1] has addressed the key challenges in and the controversies surrounding nongenetic inheritance. However, crucial findings that are important to counter two major criticisms held against transgenerational inheritance, especially in mammals - namely epigenetic memory survival across generations, and soma-to-germline transfer of heritable information - need additional discussion. Given the far-reaching implications of nongenetic inheritance on the one hand, and the skepticisms about its existence on the other, it is important that the advances concerned are examined deeply. The following discussion fills the gap left by Szyf [1] and provides an integrated perspective. © 2015 Elsevier Ltd.

Chaturvedi D.,CSIR - Central Electrochemical Research Institute
Tetrahedron | Year: 2012

In this review, various kinds of synthetic methodologies for the synthesis of organic carbamates employing diversity of reagents and catalytic systems have been reviewed, from the beginning to the recent reports (covering till December 2010). © 2011 Elsevier Ltd.

Goel A.,CSIR - Central Electrochemical Research Institute | Kumar A.,CSIR - Central Electrochemical Research Institute | Raghuvanshi A.,CSIR - Central Electrochemical Research Institute
Chemical Reviews | Year: 2013

Nature is a phenomenal source of biologically active simple and complex molecules having oxygen heterocyclic scaffolds such as flavonoids, isoflavonoids, pyranones, coumarins, and their benzannulated compounds. These oxygen heerocyclic compounds are originated from eclectic array of plants and marine sources through various de novo selective enzymatic reactions in a combinatorial fashion. To date, no review is available that deals with stereochemical aspects, chemical reactivity, or total syntheses of natural pterocarpans. To the surprise, many reports are published with ambiguous stereochemistry at positions 6a and 11a of pterocarpans. Considering the importance of the unique conformations of the pterocarpans and their biological activities, this review is concerned with conformational studies, assignment of absolute configurations, and state-of-the-art methodologies for their syntheses.

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