North - Eastern Hill University
Shillong, India

North Eastern Hill University is a Central University established on 19 July 1973 by an Act of the Indian Parliament. The university is in the suburb of Shillong, the state capital of Meghalaya, India. The university has two campuses: Shillong and Tura in Meghalaya. NEHU Tura Campus functions under a pro-vice chancellor.It is the University Grants Commission's University with Potential for Excellence . It was established as a regional university for the states of northeast India, including Meghalaya, Nagaland, Arunachal Pradesh and Mizoram, and had given birth to Nagaland University in 1994 and Mizoram University in 2001. The university at the national level ranks at 16 according to the India Today AC-Nielsen Best Universities Survey of 2012, and at 11 at the TOP Central Universities. It also has a world ranking at 1821 by the University Raking by Academic Performance. Wikipedia.

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Chatterjee A.,North - Eastern Hill University
Nutrients | Year: 2013

The tripeptide glutathione (GSH) is the most abundant intracellular nonprotein thiol, and it is involved in many cellular functions including redox-homeostatic buffering. Cellular radiosensitivity has been shown to be inversely correlated to the endogenous level of GSH. On the other hand, controversy is raised with respect to its role in the field of radioprotection since GSH failed to provide consistent protection in several cases. Reports have been published that DNA repair in cells has a dependence on GSH. Subsequently, S-glutathionylation (forming mixed disulfides with the protein-sulfhydryl groups), a potent mechanism for posttranslational regulation of a variety of regulatory and metabolic proteins when there is a change in the celluar redox status (lower GSH/GSSG ratio), has received increased attention over the last decade. GSH, as a single agent, is found to affect DNA damage and repair, redox regulation and multiple cell signaling pathways. Thus, seemingly, GSH does not only act as a radioprotector against DNA damage induced by X-rays through glutathionylation, it may also act as a modulator of the DNA-repair activity. Judging by the number of publications within the last six years, it is obvious that the field of protein glutathionylation impinges on many aspects of biology, from regulation of protein function to roles of cell cycle and apoptosis. Aberrant protein glutathionylation and its association with cancer and other diseases is an area of increasing interest. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Das G.,North - Eastern Hill University
Journal of Molecular Modeling | Year: 2013

A set of six dipeptides containing pyrrolysine invariably at their N-terminal positions is studied in gas and aqueous phase using a polarizable continuum model (PCM). The molecular geometries of the dipeptides are fully optimized at B3LYP/6-31++G(d,p) level of theory and a second derivative (frequency) analysis confirms that all the optimized geometries are true minima. The effects of solvation and identity of the varying C-terminal residue on the energetics, structural features of the peptide planes, values of the Ψ and φ dihedrals, geometry around the α-carbon atoms and theoretically predicted vibrational spectra of the dipeptides are thoroughly analyzed. Solvation effects are found to modify the gas phase conformation of the dipeptides around Ψ dihedrals while the identity of the varying C-terminal residue affect the values of φ, planarity of the peptide planes and geometry around the α-carbon atoms. The presence or absence of three types of intramolecular H-bonds, namely O⋯H-N, N⋯H-N and O⋯H-C that leave noticeable signatures in the IR spectra, play crucial roles in influencing the geometry of the peptide planes and in determining the energetics of the dipeptides. © 2013 Springer-Verlag Berlin Heidelberg.

Potentilla fulgens has been used for a long time as folk remedy for a variety of ailments without having information on its pharmacological action. The study was intended to determine the effectiveness in antitumor activity among kaempferol (KMP) as flavonoids, ellagic acid (ELA) as polyphenols and methanolic extract of the root of P. fulgens (PRE) in Ehrlich ascites tumour (EA) and MCF-7 cancer cells. The total phenolic and flavonoid content were found to be 138.8 ± 1.6 mg gallic acid and 401.6 ± 4.6 mg quercetin per 1 gm of the extract, respectively. The extract resulted in increasing in vivo survivality of mice bearing EA cells and loss of cell viability in a dose-dependent manner in MCF-7 cells. This effect may be attributed to apoptotic cell death as confirmed by flow cytometric analysis and PARP1 proteolysis. Such induction of apoptosis was achieved by suppression of inhibitor of the apoptosis protein survivin. It was observed that endogenous level of glutathione was depleted significantly in MCF-7 cells after the treatment with PRE only but not with KMP or ELA. This induction of apoptotic cell death and lowering the level of glutathione are highly desirable mode for an anticancer agent.

Advanced oxidation processes (AOPs) catalyzed by iron, Fenton (Fe 2+/H 2O 2) and photo- Fenton (Fe 2+/H 2O 2/UV) processes have been shown to have great potential in the treatment of various hazardous chemicals like dyes, agrochemicals, drugs etc. More than six decades after the discovery of Fenton's reagent, it has gained considerable importance in such a context. The present work reports details of operational parameters such as the pH, the concentrations of the target molecule, iron salt, hydrogen peroxide etc. for the working of Fenton and photo-Fenton processes efficiently. This review emphasizes two relatively neglected areas of research concerning Fenton and photo-Fenton processes, i.e. the influence of aromatic & aliphatic hydrocarbons and various inorganic cations (Cu +, CO 2-, Ni 2+, Mn 2+ etc.) and anions (e.g. ClO 4 -, SO 4 2-, Cl -, PO 4 3-, NO 3, CO 3 2-, etc.), gemrally found in industrial wastewaters on the two processes. A general mechanism of degradation of aromatic hydrocarbon systems including azo dyes has been outlined. It is concluded that hydroxyl radical mediated degradation of all aromatic hydrocarbons follows two distinct paths yielding aliphatic carboxylic acids: one through the cleavage ofperoxyl radical and the other through the cleavage of quinone. Complete mineralization is achieved when the acids on further oxidation produce CO 2 and H 2O.

Sarma H.,North - Eastern Hill University
Journal of Environmental Science and Technology | Year: 2011

Metal hyperaccumulation is a characteristic present in over 500 plant species and approximately in 0.2% of all angiosperms. Hyper accumulators are model plants for phytoremediation as they are tolerant to heavy metals. Metals hyperaccumulation and tolerance are genetically inherited traits. Plants possess a range of potential cellular mechanisms that may be involved in the detoxification of heavy metals and thus tolerance to metal stress. Recent discovery have given first insights into the molecular basis of metal hyperaccumulation and metal hypertolerance in some plants. However, the ecological and biological significance of hyperaccumulation is not clear yet. The recent progress of molecular techniques has helped to improve the performance of phytoremediation technology as well as plant adaptation to extreme metallic environments. The knowledge of metal hyperaccumulation physiology has recently developed as a result of the advancement of molecular biology. Molecular technique help to understand the gene regulations system and plant metal homeostasis. This study reviews the recent advances of phytoremediation technology using hyperaccumulator plants addressing both potential and limitations, physiological and molecular aspects and provides a broad overview of most important genes which have been correlated to metals hyperaccumulation and tolerance, evidence of the effect of heavy metal on biomass productions, plant biochemical, antioxidant defence system and discusses the prospects of transgenic plants in phytoremediation of heavy metals. © 2011 Asian Network for Scientific Information.

The Nymphaeales (waterlilly and relatives) lineage has diverged as the second branch of basal angiosperms and comprises of two families: Cabombaceae and Nymphaceae. The classification of Nymphaeales and phylogeny within the flowering plants are quite intriguing as several systems (Thorne system, Dahlgren system, Cronquist system, Takhtajan system and APG III system (Angiosperm Phylogeny Group III system) have attempted to redefine the Nymphaeales taxonomy. There have been also fossil records consisting especially of seeds, pollen, stems, leaves and flowers as early as the lower Cretaceous. Here we present an in silico study of the order Nymphaeales taking maturaseK (matK) and internal transcribed spacer (ITS2) as biomarkers for phylogeny reconstruction (using character-based methods and Bayesian approach) and identification of motifs for DNA barcoding. The Maximum Likelihood (ML) and Bayesian approach yielded congruent fully resolved and well-supported trees using a concatenated (ITS2+ matK) supermatrix aligned dataset. The taxon sampling corroborates the monophyly of Cabombaceae. Nuphar emerges as a monophyletic clade in the family Nymphaeaceae while there are slight discrepancies in the monophyletic nature of the genera Nymphaea owing to Victoria-Euryale and Ondinea grouping in the same node of Nymphaeaceae. ITS2 secondary structures alignment corroborate the primary sequence analysis. Hydatellaceae emerged as a sister clade to Nymphaeaceae and had a basal lineage amongst the water lilly clades. Species from Cycas and Ginkgo were taken as outgroups and were rooted in the overall tree topology from various methods. MatK genes are fast evolving highly variant regions of plant chloroplast DNA that can serve as potential biomarkers for DNA barcoding and also in generating primers for angiosperms with identification of unique motif regions. We have reported unique genus specific motif regions in the Order Nymphaeles from matK dataset which can be further validated for barcoding and designing of PCR primers. Our analysis using a novel approach of sequence-structure alignment and phylogenetic reconstruction using molecular morphometrics congrue with the current placement of Hydatellaceae within the early-divergent angiosperm order Nymphaeales. The results underscore the fact that more diverse genera, if not fully resolved to be monophyletic, should be represented by all major lineages.

Kma L.,North - Eastern Hill University
Asian Pacific Journal of Cancer Prevention | Year: 2014

Radiation exposure leads to several pathophysiological conditions, including oxidative damage, inflammation and fibrosis, thereby affecting the survival of organisms. This review explores the radiation countermeasure properties of fourteen (14) plant extracts or plant-derived compounds against these cellular manifestations. It was aimed at evaluating the possible role of plants or its constituents in radiation countermeasure strategy. All the 14 plant extracts or compounds derived from it and considered in this review have shown some radioprotection in different in vivo, ex-vivo and or in vitro models of radiological injury. However, few have demonstrated advantages over the others. C. majus possessing antioxidant, anti-inflammatory and immunomodulatory effects appears to be promising in radioprotection. Its crude extracts as well as various alkaloids and flavonoids derived from it, have shown to enhance survival rate in irradiated mice. Similarly, curcumin with its antioxidant and the ability to ameliorate late effect of radiation exposure, combined with improvement in survival in experimental animal following irradiation, makes it another probable candidate against radiological injury. Furthermore, the extracts of P. hexandrum and P. kurroa in combine treatment regime, M. piperita, E. officinalis, A. sinensis, nutmeg, genistein and ginsan warrants further studies on their radioprotective potentials. However, one that has received a lot of attention is the dietary flaxseed. The scavenging ability against radiation-induced free radicals, prevention of radiation-induced lipid peroxidation, reduction in radiation cachexia, level of inflammatory cytokines and fibrosis, are some of the remarkable characteristics of flaxseed in animal models of radiation injury. While countering the harmful effects of radiation exposure, it has shown its ability to enhance survival rate in experimental animals. Further, flaxseed has been tested and found to be equally effective when administered before or after irradiation, and against low doses (≥5 Gy) to the whole body or high doses (12-13.5 Gy) to the whole thorax. This is particularly relevant since apart from the possibility of using it in pre-conditioning regime in radiotherapy, it could also be used during nuclear plant leakage/accidents and radiological terrorism, which are not pre-determined scenarios. However, considering the infancy of the field of plant-based radioprotectors, all the above-mentioned plant extracts/plant-derived compounds deserves further stringent study in different models of radiation injury.

Chandra A.K.,North - Eastern Hill University
Journal of Molecular Modeling | Year: 2012

The mechanism, kinetics and thermochemistry of the gas-phase reactions between CHF2OCHF2 (HFE-134) and OH radical are investigated using the high level ab initio G2(MP2) and hybrid density functional model MPWB1K quantum chemical methods. Two relatively close in energy conformers are found for CHF2OCHF2 molecule; both of them are likely to be important in the temperature range (250-1000 K) of our study. The hydrogen abstraction pathway for both the conformers with OH radical is studied and the rate constants are determined for the first time in a wide temperature range of 250 - 1000 K. The G2(MP2) calculated total rate constant value of 2.9×10-15 cm3 molecule-1 s-1 at 298 K is found to be in very good agreement with the reported experimental value of 2.4×10-15 cm3 molecule-1 s-1 at 298 K. The heats of reaction for CHF2OCHF2+OH reaction is computed to be -13.2 kcal mol-1. The atmospheric lifetime of CHF 2OCHF2 is expected to be around 12 years. © Springer-Verlag 2012.

Khatua S.,University of Siegen | Khatua S.,North - Eastern Hill University | Schmittel M.,University of Siegen
Organic Letters | Year: 2013

A bis-heteroleptic Ru(II) complex (1) is presented that acts as a single molecular dual analyte sensor and quantifies Hg2+ and Ag+ by luminescence at two different wavelengths. The sensor has stronger binding to Hg2+ than to its likely competitor Ag+ allowing quantification of Hg2+ in a sample with Ag+ without a masking agent. 1 also selectively senses Ag+ in the absence of Hg2+ by enhancing the PL intensity at a different wavelength. © 2013 American Chemical Society.

Kma L.,North - Eastern Hill University
Asian Pacific Journal of Cancer Prevention | Year: 2013

Cancers will continue to be a threat to health unless they can be controlled by combinations of treatment modalities. In this review, evaluate the role of resveratrol (RSV) as a radiosensitizing agent was evaluated and underlying mechanisms holistically explored in different cancer models focusing on therapeutic possibilities. The ability of RSV to modify the effect of radiation exposure in normal and cancer cells has indeed been shown quite convincingly, the combination of RSV and IR exhibiting synergistic effects on different cancer cells. This is relevant since controlled exposure to IR is one of the most frequently applied treatments in cancer patients. However, radiotherapy (XRT) treatment regimes are very often not effective in clinical practice as observed in patients with glioma, prostate cancer (PCa), melanoma, for example, largely due to tumour radioresistant properties. Sensitization of IR-induced apoptosis by natural products such as RSV is likely to be relevant in cancer control and treatment. However, all cancers do not respond to RSV+IR in a similar manner. Therefore, for those such as the radioresistant PCa or melanoma cells, the RSV+IR regime has to be very carefully chosen in order to achieve effective and desirable outcomes with minimum toxicity to normal cells. They are reports that the highest concentration of 100 mM RSV and highest dose of 5 Gy IR are sufficient to kill cells by induction of apoptosis, indicating that RSV is effective in radiosensitizing otherwise radioresistant cells. In general, it has been shown in different cancer cells that RSV+XRT effectively act by enhancing expression of anti-proliferative and pro-apoptotic molecules, and inhibiting pro-proliferative and anti-apoptotic molecules, leading to induction of apoptosis through various pathways, and cell death. If RSV+XRT can suppress the signature of cancer stemness, enhance the radiosensitivity by either targeting the mitochondrial functionality or modulating the tumour necrosis factor-mediated or Fas-FasL-mediated pathways of apoptosis in different cancers, particularly in vivo, its therapeutic use in the control of cancers holds promise in the near future.

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