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Pratima Chaudhuri

Bio: Pratima Chaudhuri is an academic researcher from Amity Institute of Biotechnology. The author has contributed to research in topics: Osmolyte & Dihydrofolate reductase. The author has an hindex of 5, co-authored 14 publications receiving 78 citations. Previous affiliations of Pratima Chaudhuri include National Institutes of Natural Sciences, Japan & Amity University.

Papers
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Journal ArticleDOI
27 Jan 2014-PLOS ONE
TL;DR: Purified MCA2 in a detergent-solubilized state formed a tetramer, which was confirmed by chemical cross-linking and appears to comprise a small transmembrane region and large cytoplasmic region.
Abstract: Mechanosensing in plants is thought to be governed by sensory complexes containing a Ca2+-permeable, mechanosensitive channel. The plasma membrane protein MCA1 and its paralog MCA2 from Arabidopsis thaliana are involved in mechanical stress-induced Ca2+ influx and are thus considered as candidates for such channels or their regulators. Both MCA1 and MCA2 were functionally expressed in Sf9 cells using a baculovirus system in order to elucidate their molecular natures. Because of the abundance of protein in these cells, MCA2 was chosen for purification. Purified MCA2 in a detergent-solubilized state formed a tetramer, which was confirmed by chemical cross-linking. Single-particle analysis of cryo-electron microscope images was performed to depict the overall shape of the purified protein. The three-dimensional structure of MCA2 was reconstructed at a resolution of 26 A from 5,500 particles and appears to comprise a small transmembrane region and large cytoplasmic region.

28 citations

Journal Article
TL;DR: In the present study, it was observed that a few osmolytes effectively enhance the expression and functionality of zDHFR and hence provide substantial stability to the protein with glucose, sucrose and betaine being the exception.
Abstract: In vivo study of Zebrafish dihydrofolate reductase (zDHFR), a 23 kDa monomeric protein was studied to check the expression level in the presence of sorbitol, glycerol, proline, glycine, glucose, sucrose and betaine. Different osmolytes, also known as chemical chaperones, assist in expression enhancement of protein. In the present study, it was observed that a few osmolytes effectively enhance the expression and functionality of zDHFR and hence provide substantial stability to the protein with glucose, sucrose and betaine being the exception. A general strategy to improve the activity of recombinant proteins would be to increase the cellular concentration of viscous organic compounds, termed osmolytes, or of molecular chaperones that can prevent aggregation and convert it into native active species of commercial and pharmacological importance.

10 citations

Journal ArticleDOI
TL;DR: A comparative study of various species of DHFR shows that zDHFR has comparable thermodynamic stability with human counterpart and thus proved to be a good in vitro model system for structure- function relationship studies.

10 citations

Journal ArticleDOI
TL;DR: This study is consequential in increasing the production of functional and soluble protein in the cell extract and will also be appropriate to find a therapeutic agent against many neurodegenerative diseases.

9 citations

Journal Article
TL;DR: Applicability of polymerase chain reaction (PCR) assay to detect Pasteurella multocida in experimentally infected embryonated chicken egg was assessed and revealed that PCR assays could be employed directly for detection and confirmation of P.Multocida infection in experimental infected chicken embryos.
Abstract: Applicability of polymerase chain reaction (PCR) assay to detect Pasteurella multocida in experimentally infected embryonated chicken egg was assessed in the present study. PCR assay rapidly and specifically detected the genome of P. multocida in amniotic fluid, allantoic fluid and homogenates of infected embryo and its membranes. The sensitivity of detection was as low as 20 bacterial cells/ml of allantoic or amniotic fluids. Detection of P. multocida in dead embryos by PCR was possible up to 6 and 30 days or more following storage of dead embryos at 37 degrees C, and at 4 degrees C as well as at -20 degrees C, respectively. The study revealed that PCR assays could be employed directly for detection and confirmation of P. multocida infection in experimentally infected chicken embryos.

9 citations


Cited by
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Journal ArticleDOI
TL;DR: Key Ca2+ -mediated reactions have now been associated with the activities of specific subunits from these families, including cyclic nucleotide-gated channels, ionotropic glutamate receptors, two-pore channel 1 (TPC1), annexins and several types of mechanosensitive channels.
Abstract: Contents Summary 49 I. Introduction 49 II. Physiological and structural characteristics of plant Ca2+ -permeable ion channels 50 III. Ca2+ extrusion systems 61 IV. Concluding remarks 64 Acknowledgements 64 References 64 SUMMARY: Calcium is an essential structural, metabolic and signalling element. The physiological functions of Ca2+ are enabled by its orchestrated transport across cell membranes, mediated by Ca2+ -permeable ion channels, Ca2+ -ATPases and Ca2+ /H+ exchangers. Bioinformatics analysis has not determined any Ca2+ -selective filters in plant ion channels, but electrophysiological tests do reveal Ca2+ conductances in plant membranes. The biophysical characteristics of plant Ca2+ conductances have been studied in detail and were recently complemented by molecular genetic approaches. Plant Ca2+ conductances are mediated by several families of ion channels, including cyclic nucleotide-gated channels (CNGCs), ionotropic glutamate receptors, two-pore channel 1 (TPC1), annexins and several types of mechanosensitive channels. Key Ca2+ -mediated reactions (e.g. sensing of temperature, gravity, touch and hormones, and cell elongation and guard cell closure) have now been associated with the activities of specific subunits from these families. Structural studies have demonstrated a unique selectivity filter in TPC1, which is passable for hydrated divalent cations. The hypothesis of a ROS-Ca2+ hub is discussed, linking Ca2+ transport to ROS generation. CNGC inactivation by cytosolic Ca2+ , leading to the termination of Ca2+ signals, is now mechanistically explained. The structure-function relationships of Ca2+ -ATPases and Ca2+ /H+ exchangers, and their regulation and physiological roles are analysed.

245 citations

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TL;DR: How shared sequence homology with fungal self-incompatibility proteins and the mammalian mixed lineage kinase domain like pseudokinase (MLKL) proteins informs a plausible model for the structure and function of an ancient clade of plant hNLRs, called RNLs is discussed.

170 citations

Journal ArticleDOI
TL;DR: Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families, which are still likely to represent only a fraction of the MS ion channel diversity in plant systems.
Abstract: Mechanosensitive (MS) ion channels are a common mechanism for perceiving and responding to mechanical force. This class of mechanoreceptors is capable of transducing membrane tension directly into ion flux. In plant systems, MS ion channels have been proposed to play a wide array of roles, from the perception of touch and gravity to the osmotic homeostasis of intracellular organelles. Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families. Channels from these families vary widely in structure and function, localize to multiple cellular compartments, and conduct chloride, calcium, and/or potassium ions. However, they are still likely to represent only a fraction of the MS ion channel diversity in plant systems.

159 citations

Journal ArticleDOI
TL;DR: Molecular identity, structural features and roles of the Ca2-permeable channels involved in early salinity and osmotic signaling, and the interrelationships among spatiotemporal dynamic changes in cytosolic concentrations of free Ca2+, Rboh-mediated ROS production, and downstream signaling events during salinity adaptation in planta are reviewed.
Abstract: Salinity stress, which induces both ionic and osmotic damage, impairs plant growth and causes severe reductions in crop yield. Plants are equipped with defense responses against salinity stress such as regulation of ion transport including Na+ and K+, accumulation of compatible solutes and stress-related gene expression. The initial Ca2+ influx mediated by plasma membrane ion channels has been suggested to be crucial for the adaptive signaling. NADPH oxidase (Nox)-mediated deliberate production of reactive oxygen species (ROS) has also been suggested to play crucial roles in regulating adaptation to salinity stress in several plant species including halophytes. Respiratory burst oxidase homolog (Rboh) proteins show the ROS-producing Nox activity, which are synergistically activated by the binding of Ca2+ to EF-hand motifs as well as Ca2+-dependent phosphorylation. We herein review molecular identity, structural features and roles of the Ca2+-permeable channels involved in early salinity and osmotic signaling, and comparatively discuss the interrelationships among spatiotemporal dynamic changes in cytosolic concentrations of free Ca2+, Rboh-mediated ROS production, and downstream signaling events during salinity adaptation in planta.

139 citations

Journal ArticleDOI
TL;DR: The current status in Ca2+ signaling-mediated cold tolerance in plants is highlighted and the role of Ca2+, involved in cold stress response needs to be further elucidated.
Abstract: Low temperatures have adverse impacts on plant growth, developmental processes, crop productivity and food quality. It is becoming clear that Ca2+ signaling plays a crucial role in conferring cold tolerance in plants. However, the role of Ca2+ involved in cold stress response needs to be further elucidated. Recent studies have shown how the perception of cold signals regulate Ca2+ channels to induce Ca2+ transients. In addition, studies have shown how Ca2+ signaling and its cross-talk with nitric oxide (NO), reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling pathways ultimately lead to establishing cold tolerance in plants. Ca2+ signaling also plays a key role through Ca2+/calmodulin-mediated Arabidopsis signal responsive 1 (AtSR1/CAMTA3) when temperatures drop rapidly. This review highlights the current status in Ca2+ signaling-mediated cold tolerance in plants.

122 citations