https://libjncir.jncasr.ac.in/xmlui/handle/10572/19 2026-04-04T05:30:29Z 2026-04-04T05:30:29Z Maity, Debabrata Raj, Anand Samanta, Pralok K. Karthigeyan, D. Kundu, Tapas Kumar Pati, Swapan Kumar Govindaraju, T. https://libjncir.jncasr.ac.in/xmlui/handle/10572/2485 2017-02-21T10:24:43Z 2014-01-01T00:00:00Z

A probe for ratiometric near-infrared fluorescence and colorimetric hydrogen sulfide detection and imaging in live cells Maity, Debabrata; Raj, Anand; Samanta, Pralok K.; Karthigeyan, D.; Kundu, Tapas Kumar; Pati, Swapan Kumar; Govindaraju, T. A ratiometric, near-infrared (NIR), fluorescence and colorimetric probe DNPOCy for hydrogen sulfide (H2S) has been developed. The chemical basis for the operation of the probe is thiolysis of a dinitrophenyl ether, which liberates a cyanine dye chromophore. The probe exhibits a rapid response and high sensitivity to H2S in pure aqueous media, in the near infrared optical window. DNPOCy is highly selective for H2S over other biologically relevant species including biothiols. This probe can be conveniently used for monitoring H2S without the interference from pH dependent effects of physiological media. The practical utility of the probe was demonstrated by its application to the detection of H2S in live cells. Restricted Access

2014-01-01T00:00:00Z Suresh, Venkata M. Chatterjee, Snehajyoti Modak, Rahul Tiwari, Vivek Patel, Anant B. Kundu, Tapas Kumar Maji, Tapas Kumar https://libjncir.jncasr.ac.in/xmlui/handle/10572/2433 2017-02-21T10:25:06Z 2014-01-01T00:00:00Z

Oligo(p-phenyleneethynylene)-Derived Porous Luminescent Nanoscale Coordination Polymer of Gd-III: Bimodal Imaging and Nitroaromatic Sensing Suresh, Venkata M.; Chatterjee, Snehajyoti; Modak, Rahul; Tiwari, Vivek; Patel, Anant B.; Kundu, Tapas Kumar; Maji, Tapas Kumar Self-assembled highly luminescent nanoscale coordination polymer of {[Gd(OPE)(NO3)(H2O)2]center dot H2O} (NCP-1), (oligo-(p-phenyleneethynylene)dicarboxylate) was synthesized by coordination-driven self-assembly of oligo-(p-phenyleneethynylene)dicarboxylic acid and Gel in polar solvent under refluxing conditions. This nanostructure has been characterized by FESEM, TEM, powder X-ray diffraction, and adsorption study. Interdigitation between ID coordination polymers through alkyl chains results in a porous supramolecular 3D extended structure. NCP-1 shows permanent microporosity as revealed by type-I CO2 uptake profile. FESEM and TEM studies of NCP-1 reveal nanorod-like morphology with square-type cross section having dimensions of 50-100 nm diameter and 0.5-0.8 pm length. High-magnification TEM images show long-range structural ordering present in NCP-1 with uniform dark lines having an interspacing distance of 0.9-1.1 nm. Physiological stability and strong luminescence features of NCP-1 have been exploited for bioimaging based on internalization into mammalian cultured cell lines HEK 293T and H1299. Magnetic resonance imaging studies suggest that NCP-1 could act as a potential negative (T2) contrast agent. Furthermore, this porous luminescent NCP-1 shows efficient nitroaromatic sensing as realized by the fluorescence quenching in solution as well as in vapor phase of the analyte like 2,4-dinitrotoluene (2,4-DNT). These results demonstrate that hybridization of a paramagnetic metal center and luminescent linker in a nanoscale porous coordination polymer culminates in a functional hybrid material with potential bimodal imaging and sensing applications. Restricted Access

2014-01-01T00:00:00Z Srivastava, Sandeep Bhowmick, Krishanu Chatterjee, Snehajyoti Basha, Jeelan Kundu, Tapas Kumar Dhar, Suman K. https://libjncir.jncasr.ac.in/xmlui/handle/10572/2333 2017-02-21T10:23:48Z 2014-01-01T00:00:00Z

Histone H3K9 acetylation level modulates gene expression and may affect parasite growth in human malaria parasite Plasmodium falciparum Srivastava, Sandeep; Bhowmick, Krishanu; Chatterjee, Snehajyoti; Basha, Jeelan; Kundu, Tapas Kumar; Dhar, Suman K. Three-dimensional positioning of the nuclear genome plays an important role in the epigenetic regulation of genes. Although nucleographic domain compartmentalization in the regulation of epigenetic state and gene expression is well established in higher organisms, it remains poorly understood in the pathogenic parasite Plasmodium falciparum. In the present study, we report that two histone tail modifications, H3K9Ac and H3K14Ac, are differentially distributed in the parasite nucleus. We find colocalization of active gene promoters such as Tu1 (tubulin-1 expressed in the asexual stages) with H3K9Ac marks at the nuclear periphery. By contrast, asexual stage inactive gene promoters such as Pfg27 (gametocyte marker) and Pfs28 (ookinete marker) occupy H3K9Ac devoid zones at the nuclear periphery. The histone H3K9 is predominantly acetylated by the PCAF/GCN5 class of lysine acetyltransferases, which is well characterized in the parasite. Interestingly, embelin, a specific inhibitor of PCAF/GCN5 family histone acetyltransferase, selectively decreases total H3K9Ac acetylation levels (but not H3K14Ac levels) around the var gene promoters, leading to the downregulation of var gene expression, suggesting interplay among histone acetylation status, as well as subnuclear compartmentalization of different genes and their activation in the parasites. Finally, we found that embelin inhibited parasitic growth at the low micromolar range, raising the possibility of using histone acetyltransferases as a target for antimalarial therapy. Restricted Access

2014-01-01T00:00:00Z Swaminathan, Amrutha Kumar, Manoj Sinha, Sarmistha Haider Schneider-Anthony, Anne Boutillier, Anne-Laurence Kundu, Tapas Kumar https://libjncir.jncasr.ac.in/xmlui/handle/10572/2335 2017-02-21T10:23:52Z 2014-01-01T00:00:00Z

Modulation of Neurogenesis by Targeting Epigenetic Enzymes Using Small Molecules: An Overview Swaminathan, Amrutha; Kumar, Manoj; Sinha, Sarmistha Haider; Schneider-Anthony, Anne; Boutillier, Anne-Laurence; Kundu, Tapas Kumar Neurogenesis consists of a plethora of complex cellular processes including neural stem cell (NSC) proliferation, migration, maturation or differentiation to neurons, and finally integration into the pre-existing neural circuits in the brain, which are temporally regulated and coordinated sequentially. Mammalian neurogenesis begins during embryonic development and continues in postnatal brain (adult neurogenesis). It is now evident that adult neurogenesis is driven by extracellular and intracellular signaling pathways, where epigenetic modifications like reversible histone acetylation, methylation, as well as DNA methylation play a vital role. Epigenetic regulation of gene expression during neural development is governed mainly by histone acetyltransferases (HATs), histone methyltransferase (HMTs), DNA methyltransferases (DNMTs), and also the enzymes for reversal, like histone deacetylases (HDACS), and many of these have also been shown to be involved in the regulation of adult neurogenesis. The contribution of these epigenetic marks to neurogenesis is increasingly being recognized, through knockout studies and small molecule modulator based studies. These small molecules are directly involved in regeneration and repair of neurons, and not only have applications from a therapeutic point of view, but also provide a tool to study the process of neurogenesis itself. In the present Review, we will focus on small molecules that act predominantly on epigenetic enzymes to enhance neurogenesis and neuroprotection and discuss the mechanism and recent advancements in their synthesis, targeting, and biology. Restricted Access

2014-01-01T00:00:00Z