Dārjiling, India
Dārjiling, India

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Mitra S.,Darjeeling Government College | Burger B.V.,Stellenbosch University | Poddar-Sarkar M.,University of Calcutta
Protoplasma | Year: 2016

Mosses have an inherent adaptability against different biotic and abiotic stresses. Oxylipins, the volatile metabolites derived from polyunsaturated fatty acids (PUFAs), play a key role in the chemical defence strategy of mosses. In the present study, a comparative survey of these compounds, including an investigation into their precursor fatty acids (FAs), was carried out for the first time on the mosses Brachymenium capitulatum (Mitt.) Paris, Hydrogonium consanguineum (Thwaites & Mitt.) Hilp., Barbula hastata Mitt., and Octoblepharum albidum Hedw. collected from the Eastern Himalayan Biodiversity hotspot. Their headspace volatiles were sampled using a high-efficiency sample enrichment probe (SEP) and were characterized by gas chromatography-mass spectrometric analysis. FAs from neutral lipid (NL) and phospholipid (PL) fractions were also evaluated. Analysis of the oxylipin volatilome revealed the generation of diverse metabolites from C5 to C18, dominated by alkanes, alkenes, saturated and unsaturated alcohols, aldehydes, ketones and cyclic compounds, with pronounced structural variations. The C6 and C8 compounds dominated the total volatilome of all the samples. Analyses of FAs from membrane PL and storage NL highlighted the involvement of C18 and C20 PUFAs in oxylipin generation. The volatilome of each moss is characterized by a ‘signature oxylipin mixture’. Quantitative differences in the C6 and C8 metabolites indicate their phylogenetic significance. © 2016 Springer-Verlag Wien


Chakraborty S.,Darjeeling Government College | Ray M.,University of Calcutta | Ray S.,University of Calcutta
Fish and Shellfish Immunology | Year: 2010

Toxicity of arsenic was investigated in the gill of Lamellidens marginalis by exposing the animals to sublethal concentrations of sodium arsenite for a maximum period of 30 days in controlled laboratory conditions. Arsenite exposure inhibited the activities of acid phosphatase (ACP), alkaline phosphatase (ALP), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and acetlycholinesterase (AChE) in a dose and time dependent manner. Depletion in cytotoxic molecule like nitric oxide (NO) and suppression of phenoloxidase (PO) activity suggests an immune compromise in the animal. Inhibition in the activities of glutathione-s-transferase (GST) and catalase (CAT) in the species indicate impairment of its vital detoxification process and elevated oxidative stress respectively. Histopathology of the gill indicates arsenite induced damage of the organ leading to its possible dysfunction. The toxic exposure ravaged the structure and impaired the functions of the gill of the animal which might restrict its proper gaseous exchange, filter feeding and elicitation of immune responses against pathogens. © 2010 Elsevier Ltd.


Tamang A.,Darjeeling Government College | Potapov A.A.,Bashkir State University | Lukmanova R.,M. Akmullah Bashkir State Pedagogical University | Izmailov R.,M. Akmullah Bashkir State Pedagogical University | Nandi K.K.,North Bengal University
Classical and Quantum Gravity | Year: 2015

In this paper, we wish to investigate certain observable effects in the recently obtained wormhole solution of the Eddington-inspired Born-Infeld (EiBI) theory, which generalizes the zero-mass Ellis-Bronnikov wormhole of general relativity. The solutions of EiBI theory contain an extra parameter κ having the inverse dimension of the cosmological constant Λ, and which is expected to modify various general relativistic observables such as the masses of wormhole mouths, tidal forces and light deflection. A remarkable result is that a non-zero κ could prevent the tidal forces in the geodesic orthonormal frame from becoming arbitrarily large near a small throat radius (r0 ∼0) contrary to what happens near a small Schwarzschild horizon radius (M∼0). The role of κ in the flare-out and energy conditions is also analyzed, which reveals that the energy conditions are violated. We show that the exotic matter in the EiBI wormhole cannot be interpreted as a phantom (ω = pr/ρ <-1) or ghost field φ of general relativity due to the fact that both ρ and p r are negative for all κ. © 2015 IOP Publishing Ltd.


Podder S.,Darjeeling Government College | Gupta S.K.,University of Calcutta | Saha G.K.,University of Calcutta
World Allergy Organization Journal | Year: 2010

Background: The increasing trend in allergic diseases has become obvious in the present day, especially in developing countries like India, because of many factors such as change in ambient air quality, increased air pollution, metamorphic change in living habits and lifestyle, and climate.1 Mites present in house dust represent a major source of allergens, resulting in different allergic manifestations all over the world, and hypersensitivity to these dust mites may play a pivotal role in pathogenesis of several allergic complaints including bronchial asthma. The present study evaluated the sensitization toward house dust and house dust mites among patients residing in Kolkata metropolis, India, who are suffering from allergic asthma. Methods: The skin prick test was performed on a total of 1079 patients (585 males and 494 females) between the age group 5-50 years and 50 healthy controls using a variety of 16 common aero-allergenic extracts including 4 allergens of interest, viz. Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis and total house dust allergens. Total serum IgE level was measured by using the EIA technique and specific IgE levels against aforesaid allergens were detected with the Pharmacia ImmunoCAP 100 System. The influence of age and sex, if any, on allergen sensitivity was also investigated. All statistical analyses were performed using SPSS 10.0 for Windows and Zar.2 Results: The responses among patients with asthma to house dust and house dust mite allergen tests were as follows: house dust (96.22%), D. pteronyssinus (75.06%), B. tropicalis (72%), and D. farinae (63.72%). The frequency of positive skin response was found to be independent of age and sex. The total serum IgE levels in patients varied between 7.3 and 4040 IU/ml (mean 369 ± 26.51 IU/ml). Specific IgE antibody test proved that 83% patients showed sensitivity toward at least 1 of the allergens tested. Discussion: The results indicate that patients are highly sensitive to house dust and 3 other allergenic mites, namely, D. pteronyssinus, D. farinae, and B. tropicalis, as evidenced by the skin prick test, quantification of total serum IgE, and detection of allergen-specific IgE antibodies among patients of Kolkata. Although mites belonging to the genus Dermatophagoides have already been incriminated as a major source of allergen in house dust in India, this is the first time the role of B. tropicalis mites causing allergic asthma has been reported from an Indian population. Thus, the importance of B. tropicalis mite as an aetiopathological agent in causing various allergic manifestations among the Kolkata population should not be undermined and the allergen should be included in routine allergy testing. Copyright © 2010 by World Allergy Organization.


Talukdar B.,Visva Bharati University | Ghosh S.K.,Darjeeling Government College | Saha A.,Visva Bharati University | Pal D.,Bamunara L C D P Institution
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

By an appropriate choice for the phase of the complex nucleonic field and going over to the traveling coordinate, we reduce the coupled Higgs equations to the Hamiltonian form and treat the resulting equation using the dynamical system theory. We present a phase-space analysis of its stable points. The results of our study demonstrate that the equation can support both traveling- and standing-wave solutions. The traveling-wave solution appears in the form of a soliton and resides in the midst of doubly periodic standing-wave solutions. © 2013 American Physical Society.


Banerjee S.,Darjeeling Government College | Banerjee S.,University of Burdwan | Sengupta P.S.,Vivekananda Mahavidyalaya | Mukherjee A.K.,University of Burdwan
Chemical Physics Letters | Year: 2010

A hydrolysis process of the third generation orally active anticancer drug cis-[PtCl2(NH3)(2-picoline)], ZD0473 has been investigated using density functional theory. Pentacoordinated platinum transition state (TS) geometries along with other stationary points on potential energy surface were optimized and characterized including two different paths. Two explicit water molecules were included in the calculations to improve the solvation energies. To obtain accurate energies for the reaction surfaces, single-point energies were calculated by conductor-like polarisable continuum model (CPCM) using larger basis sets. The calculated results show that the second step is the rate-limiting process. The computed values of rate constant of different steps are in good agreement with the available experimental results. © 2010 Elsevier B.V. All rights reserved.


Pandit D.,Variable Energy Cyclotron Center | Mukhopadhyay S.,Variable Energy Cyclotron Center | Bhattacharya S.,Darjeeling Government College | Pal S.,Variable Energy Cyclotron Center | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

The energy spectrum of the high energy γ-rays in coincidence with the prompt γ-rays has been measured for the spontaneous fission of 252Cf. The nucleus-nucleus coherent bremsstrahlung of the accelerating fission fragments is observed and the result has been substantiated with a theoretical calculation based on the Coulomb acceleration model. The width of the giant dipole resonance (GDR) decay from the excited fission fragments has been extracted for the first time and compared with the thermal shape fluctuation model (TSFM) in the liquid drop formalism. The extracted GDR width is significantly smaller than the predictions of TSFM. © 2010 Elsevier B.V. All rights reserved.


Panda S.,Darjeeling Government College
Journal of Japanese Botany | Year: 2012

The genus Diplarche Hook. f. & Thomson (Ericaceae) is recorded for the first time from Arunachal Himalaya, India. The genus comprises two species in the world, of which D, multiflora Hook, f. & Thomson is recorded based on the Kingdon-Ward collection from Arunachal Pradesh. The species is described here along with photographs of the herbarium specimen to facilitate identification in the field.


This study, based on an investigation of morphology (as assessed through field and herbarium studies), leaf anatomy (stomata and vein islets), and pollen morphology (LM and SEM) reveals that Gaultheria stapfiana Airy Shaw is a distinct species and not a variant within of the G. hookeri C.B.Clarke as proposed by Ruizheng & P.F. Stevens (2005). Line drawings, photographs of living plants and specimens, photographs of leaf anatomical characters, and pollen of G. stapfiana and its allies, show that this species is clearly delimited from both G. hookeri and G. fragrantissima Wall. © 2012 Magnolia Press.


Das A.,Darjeeling Government College | Majumder K.,Darjeeling Government College
Scientia Horticulturae | Year: 2010

Cell-wall pectic polysaccharides were fractionated by sequential extraction with water, 1% potassium oxalate at room temperature, 0.05 M HCl at 100 °C and 0.05 M NaOH at 4 °C from the three specific tissue zones, i.e., outer pericarp (OP), middle pericarp (MP) and inner pericarp (IP) of the guava fruits during their development and ripening. The water and oxalate-soluble pectic fractions were found to increase, while acid and alkali-soluble pectic fractions had a decreasing trend at ripening phase of fruit, irrespective of the different tissue zones. However, the extent of pectic solubilization was more pronounced in IP region as compared to OP and MP zone of the fruit tissue. The differential degradation of pectic polymers thus points out that ripening as well as tissue softening of guava fruits are centrifugally expressed as evidenced by higher accumulation of sugar and soluble pectic polysaccharides in IP zone of the fruits. © 2010 Elsevier B.V. All rights reserved.

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