Institution
North Eastern Hill University
Education•Shillong, Meghalaya, India•
About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Ruthenium. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.
Topics: Population, Ruthenium, Ligand, Catalysis, Micelle
Papers published on a yearly basis
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TL;DR: These natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments.
Abstract: Uranium (U)-tolerant aerobic chemo-heterotrophic bacteria were isolated from the sub-surface soils of U-rich deposits in Domiasiat, North East India. The bacterial community explored at molecular level by amplified ribosomal DNA restriction analysis (ARDRA) resulted in 51 distinct phylotypes. Bacterial community assemblages at the U mining site with the concentration of U ranging from 20 to 100 ppm, were found to be most diverse. Representative bacteria analysed by 16S rRNA gene sequencing were affiliated to Firmicutes (51%), Gammaproteobacteria (26%), Actinobacteria (11%), Bacteroidetes (10%) and Betaproteobacteria (2%). Representative strains removed more than 90% and 53% of U from 100 µM and 2 mM uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure and the activity was retained until 24 h. Overall, 76% of characterized isolates possessed phosphatase enzyme and 53% had PIB-type ATPase genes. This study generated baseline information on the diverse indigenous U-tolerant bacteria which could serve as an indicator to estimate the environmental impact expected to be caused by mining in the future. Also, these natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments.
63 citations
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TL;DR: The present findings suggest that carbosulfan is a potent genotoxic agent and may be regarded as a potential germ cell mutagen also.
Abstract: The genotoxic effects of carbosulfan were evaluated using chromosome aberration (CA), bone marrow micronucleus (MN) and sperm abnormality assays in mice. All the three acute doses (1.25, 2.5 and 5 mg/kg) of carbosulfan induced significant dose-dependent increase in the frequency of CA ( P P P 7-fold increase in the frequency of CA, >3.5-fold increase in the frequency of micronucleated PCEs and >4.6-fold increase in the frequency of sperms with abnormal head morphology following intraperitoneal exposure as compared to the untreated controls. The present findings suggest that carbosulfan is a potent genotoxic agent and may be regarded as a potential germ cell mutagen also.
63 citations
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TL;DR: The different species and infraspecific categories of the genus Brachionus, so far reported or described from India, are reviewed and remarks are made on the ecology and epizoic nature of various species.
Abstract: The different species and infraspecific categories of the genus Brachionus, so far reported or described from India, are reviewed. Their distribution and taxonomic validity are discussed. Remarks are made on the ecology and epizoic nature of various species.
62 citations
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TL;DR: The conformational flexibility of MtbICL is studied to better understand its stability and catalytic activity and reveals internal dynamics of the enzyme structure and suggests that regions other than the active site should be exploited for targeting MtbicL inhibition and development of novel anti-tuberculosis compounds.
Abstract: Isocitrate lyase (ICL), a potential anti-tubercular drug target, catalyzes the first step of the glyoxylate shunt. In the present investigation, we studied the conformational flexibility of MtbICL to better understand its stability and catalytic activity. Our biochemical results showed that a point mutation at Phe345, which is topologically distant (>10 A) to the active site signature sequence (189KKCGH193), completely abolishes the activity of the enzyme. In depth computational analyses were carried out for understanding the structural alterations using molecular dynamics, time-dependent secondary structure and principal component analysis. The results showed that the mutated residue increased the structural flexibility and induced conformational changes near the active site (residues 170–210) and in the C-terminal lid region (residues 411–428). Both these regions are involved in the catalytic activity of MtbICL. Upon mutation, the residual mobility of the enzyme increased, resulting in a decrease in the stability, which was confirmed by the lower free energy of stabilization in the mutant enzyme suggesting the destabilization in the structure. Our results have both biological importance and chemical novelty. It reveals internal dynamics of the enzyme structure and also suggests that regions other than the active site should be exploited for targeting MtbICL inhibition and development of novel anti-tuberculosis compounds.
62 citations
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TL;DR: This account calculates adiabatic electron affinities (AEAs), which describe the energetics of electronic attachment to closed-shell DNA subunits, and predicts that most of the more complex and hydrated species are observable as radical anions.
Abstract: When DNA is damaged by ionizing radiation, the genes in a cell may acquire mutations or the cell could die. The smallest known DNA-damaging unit is an electron, often low-energy secondary electrons. Additional electrons and transfers involving hydrogen atoms, protons, and hydride anions can damage DNA subunits, including individual nucleobases and nucleoside pairs. Researchers would like to better understand the molecular mechanisms involved in DNA damage from ionizing radiation. In this Account, we highlight our theoretical investigations of the molecular mechanisms of DNA damage using quantum mechanical models. Our investigations use robust theoretical methods with computations conducted in the gas phase and with solution models. We calculate adiabatic electron affinities (AEAs), which describe the energetics of electronic attachment to closed-shell DNA subunits, for the free bases, nucleosides, nucleotides, base pairs, and single and double DNA strand units. Electron affinities for free nucleobases yield the order uracil > thymine > cytosine > guanine > adenine and the same order for the DNA nucleosides, mononucleotides, and nucleoside 3',5'-diphosphates. AEA values increase steadily with the size and complexity of the system because of greater hydration, glycosylation, nucleotide formation, and base pairing. We predict and experimental results partially confirm that most of the more complex and hydrated species are observable as radical anions. Our modeling studies indicate that depyrimidination reactions of radical anion nucleosides release cytosine more often than thymine. Recent experimental results support those findings. Our theoretical studies of DNA base-pair radical anions predict increases in electron affinity accompanying H bonding and solvation. Electron addition facilitates some proton transfers in these pairs, which results in strongly perturbed pairing configurations. Of all nucleobase moieties within the more complex radical anion systems, thymine is best able to retain a negative charge. Charge and spin are well-separated in some of these systems. Radical species derived via hydrogen abstraction from DNA subunits yield large AEA values because they form closed-shell anions. Our studies predict single-strand breaks following H abstraction from nucleotides. Some H-abstraction processes in the DNA base pairs lead to severe distortions in pairing configuration based on our calculations. This body of systematic theoretical studies provides realistic descriptions of some events that lead to elementary DNA lesions, while providing rationalizations for many observed phenomena. Such approaches can lead to the design of new experiments, which would contribute to our understanding of the chemical physics of nucleic acids.
62 citations
Authors
Showing all 2368 results
Name | H-index | Papers | Citations |
---|---|---|---|
Vivek Sharma | 150 | 3030 | 136228 |
Patrick J. Carroll | 58 | 505 | 13046 |
Majeti Narasimha Vara Prasad | 56 | 227 | 15193 |
Arun Sharma | 55 | 371 | 11364 |
Michael Schmittel | 53 | 387 | 10461 |
Birgitta Bergman | 52 | 187 | 10975 |
Harikesh Bahadur Singh | 46 | 307 | 7372 |
Lal Chand Rai | 40 | 134 | 4513 |
B. Dey | 40 | 354 | 8089 |
Hiriyakkanavar Ila | 36 | 407 | 5633 |
Jürgen-Hinrich Fuhrhop | 35 | 208 | 5130 |
Sreebrata Goswami | 34 | 142 | 3228 |
Gagan B.N. Chainy | 33 | 107 | 4151 |
J.P. Gaur | 31 | 64 | 3957 |
Hiriyakkanavar Junjappa | 30 | 349 | 4102 |