Showing papers by "North Eastern Hill University published in 2009"

Above ground standing biomass and carbon storage in village bamboos in North East India

Abstract: Bamboo forms an important component in the traditional landscape of North East India For biomass estimation of village bamboos of Barak Valley, North East India, allometric relationships were developed by harvest method describing leaf, branch and culm biomass with DBH as an independent variable using a log linear model The culm density of the stand was 8950 culms ha−1 during 2005 of which 67% of growing stock was represented by Bambusa cacharensis, 1788% by Bambusa vulgaris and 1512% by Bambusa balcooa Above ground stand biomass was 12151 t ha−1 of which 86% was contributed by culm component followed by branch (10%) and leaf (4%) With respect to species, B cacharensis made up to 46% of total stand biomass followed by B vulgaris (28%) and B balcooa (26%) Carbon storage in the above ground biomass was 6105 t ha−1 Allocation of C was more in culm components (5305 t ha−1) than in branch (581 t ha−1) and leaf (219 t ha−1) Carbon storage in the litter floor mass was 240 t ha−1, of which leaf litter made up the highest amount (137 t ha−1) followed by sheath (086 t ha−1) and branch (017 t ha−1) Carbon stock in the soil up to 30 cm depth was 573 t ha−1 Gross C stock in the plantation was estimated to be 12075 t ha−1 Carbon storage estimated in the bamboo stand of present study offers insights into the opportunity of village bamboos in the rural landscape for carbon storage through carbon sequestration Management and utilization of village bamboos as a potential source of carbon sink by smallholder farmers are discussed in the context of their livelihood security and the Millennium Development Goals of the United Nations

Amino acetate functionalized Schiff base organotin(IV) complexes as anticancer drugs: synthesis, structural characterization, and in vitro cytotoxicity studies.

Abstract: Potassium 2-{[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)]amino}-4-methyl-pentanoate (L1HK) and potassium 2-{[(E)-1-(2-hydroxyphenyl)alkylidene]amino}-4-methyl-pentanoates (L2HK-L3HK) underwent reactions with PhnSnCl4-n (n = 2 and 3) to give the amino acetate functionalized Schiff base organotin(IV) complexes [Ph3SnLH]n (1–3) and [Ph2SnL] (4), respectively. These complexes have been characterized by 1H, 13C, 119Sn NMR, IR spectroscopic techniques in combination with elemental analyses. The crystal structures of 1 and 3 were determined. The crystal structures reveal that the complexes exist as polymeric chains in which the L-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with the Ph groups in the equatorial positions and the axial locations occupied by a carboxylate oxygen atom from one carboxylate ligand and the alcoholic or phenolic oxygen atom of the next carboxylate ligand in the chain. The carboxylate ligands coordinate in the zwitterionic form with the alcoholic/phenolic proton moved to the nearby nitrogen atom. The solution structures were predicted by 119Sn NMR spectroscopy. When these organotin(IV) complexes were tested against A498, EVSA-T, H226, IGROV, M19 MEL, MCF7 and WIDR human tumor cell lines, the average ID50 values obtained were 55, 80 and 35 ng/ml for triphenyltin(IV) compounds 1–3, respectively. The most cytotoxic triphenyltin(IV) compound in the present report (3) with an average ID50 value of around 35 ng/ml is found to be more cytotoxic for all the cell lines studied than doxorubicin, cisplatin, 5-fluorouracil and etoposide.

Elementary Lesions in DNA Subunits: Electron, Hydrogen Atom, Proton, and Hydride Transfers

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.

Anthelmintic efficacy of ethanolic shoot extract of Alpinia nigra on tegumental enzymes of Fasciolopsis buski, a giant intestinal parasite.

Abstract: Ethanolic shoot extract of Alpinia nigra, a traditionally used anthelmintic medicinal plant among the Tripuri tribes of north-east India, was tested in vitro to determine its anthelmintic efficacy in gastrointestinal trematode Fasciolopsis buski, using alterations in the activity of vital tegumental enzymes viz. acid phosphatase (AcPase), alkaline phosphatase (AlkPase) and adenosine triphosphatase (ATPase). Live adult F. buski treated in vitro with different concentrations of the plant extract showed significant decline in the visible stain histochemically and enzyme activities. Quantitatively, the total enzyme activity of AcPase, AlkPase and ATPase was found to be reduced by 45, 41 and 43%, respectively compared to the control. The reference drug, praziquantel also showed more or less similar effect like that of the plant extract. The results suggest that the tegumental enzymes of the parasite may be an important target of action for active component(s) of A. nigra, which appears to act transtegumentally.

Synthesis and spectral studies of nickel(II) complexes derived from disalicylaldehyde oxaloyldihydrazone

Abstract: The mononuclear nickel(II) complex [Ni(H2slox)(H2O)3] (1) and polymeric dinuclear complexes [Ni2(slox)(A4)] {A = H2O (2), py (3), 2-pic (4), 3-pic (5) and 4-pic (6)} and the discrete binuclear complexes [Ni2(slox)(NN)3] {NN = bpy (7) and phen (8)} have been synthesized from disalicylaldehyde oxaloyldihydrazone (H4slox) in methanol. All of the complexes are nonelectrolytes. Complexes 1, 7, and 8 are paramagnetic while binuclear 2–6 possess anomalously low μ eff value, indicating considerable metal–metal interaction. Discrete binuclear 7 and 8 have no interaction between the two nickel(II) ions. The anomalously low magnetic moment values in 2–6 are explained as metal–metal interaction via phenoxide bridge. Such metal–metal interactions are less in 7 and 8 due to coordination of bipyridine and phenanthroline molecules which do not allow phenoxide bridging. The dihydrazone coordinates to the metal center as a dibasic tridentate ligand in keto-enol form in staggered configuration in 1, while in the remaining c...

Anthelmintic activity of Acacia oxyphylla stem bark against Ascaridia galli.

Abstract: The anthelmintic activity of the ethanol extract of Acacia oxyphylla Graham ex Bentham (Mimosaceae) stem bark was tested against Ascaridia galli Schrank (Nematoda), the intestinal roundworm of domestic fowl. Different concentrations of the extract (0.5, 1, 2, 5, 10 and 20 mg/mL) were prepared in 0.9% phosphate buffered saline (PBS) with 1% dimethylsulfoxide (DMSO). In vitro treatment of the adult roundworms indicated concentration-dependent efficacy of the plant extract. Similar concentrations of a broad-spectrum antiparasitic drug, albendazole, were used as a standard reference. Control experiments consisted of nematodes maintained in 0.9% PBS with 1% DMSO. Albendazole was significantly effective (P < 0.05) at all concentrations tested in causing mortality of A. galli. However, the plant extract showed concentration-dependent efficacy only at the concentrations of 2, 5, 10, and 20 mg/mL. In order to ascertain the anthelmintic effect, scanning electron microscopy was performed, which indicated devastating...

Phylogenetic reconstruction using secondary structures and sequence motifs of ITS2 rDNA of Paragonimus westermani (Kerbert, 1878) Braun, 1899 (Digenea: Paragonimidae) and related species

Abstract: Background Most phylogenetic studies using current methods have focused on primary DNA sequence information. However, RNA secondary structures are particularly useful in systematics because they include characteristics that give "morphological" information, not found in the primary sequence. In several mountainous regions of Northeastern India, foci of Paragonimus (lung fluke) infection reportedly involve species that are known to prevail in neighbouring countries. The present study was undertaken to demonstrate the sequence analysis of the ribosomal DNA (ITS2) of the infective (metacercarial) stage of the lung fluke collected from the edible crab hosts that are abundant in a mountain stream of the area (Miao, Changlang District in Arunachal Pradesh) and to construct its phylogeny. Using the approach of molecular morphometrics that is based on ITS2 secondary structure homologies, phylogenetic relationships of the various isolates of Paragonimus species that are prevalent in the neighbouring Near-eastern countries have been discussed.

Tree species distribution and its impact on soil properties, and nitrogen and phosphorus mineralization in a humid subtropical forest ecosystem of northeastern India

Abstract: The impact of tree species on net N and P mineralization, and soil properties beneath their canopy were studied in a subtropical evergreen broad-leaved forest of northeastern India. Four types of experimental plots were identified based on tree species dominance. The first plot was dominated by Myrica esculenta Buch.-Ham. ex D. Don., the second by Rhododendron arboreum Sm., the third by Neolitsea cassia Koster., and the fourth was a mixed-species plot. Organic carbon content (3.11%) and NH4+-N concentration (11.40 μg·g–1) in the Rhododendron plot, pH (4.64) and total N content (0.89%) in the mixed plot, available P (5.16 μg·g–1) and NO3–-N (8.63 μg·g–1) concentrations in the Neolitsea plot were significantly higher (p < 0.001) than the other plots. All these soil parameters were lowest in the Myrica plot. The net N and P mineralization rates in an annual cycle across different plots ranged between 18.83 and 22.14 μg·g–1·month–1 and between 4.54 and 5.87 μg·g–1·month–1, respectively. The flux varied signif...

Use of sequence motifs as barcodes and secondary structures of internal transcribed spacer 2 (ITS2, rDNA) for identification of the Indian liver fluke, Fasciola (Trematoda: Fasciolidae).

Abstract: Most phylogenetic studies using current methods have focused on primary DNA sequence information. However, RNA secondary structures are particularly useful in systematics because they include characteristics that give "morphological" information which is not found in the primary sequence. Also DNA sequence motifs from the internal transcribed spacer (ITS) of the nuclear rRNA repeat are useful for identification of trematodes. The species of liver flukes of the genus Fasciola (Platyhelminthes: Digenea: Fasciolidae) are obligate parasitic trematodes residing in the large biliary ducts of herbivorous mammals. While Fasciola hepatica has a cosmopolitan distribution, the other major species, i.e., F. gigantica is reportedly prevalent in the tropical and subtropical regions of Africa and Asia. To determine the Fasciola sp. of Assam (India) origin based on rDNA molecular data, ribosomal ITS2 region was sequenced (EF027103) and analysed. NCBI databases were used for sequence homology analysis and the phylogenetic trees were constructed based upon the ITS2 using MEGA and a Bayesian analysis of the combined data. The latter approach allowed us to include both primary sequence and RNA molecular morphometrics and revealed a close relationship with isolates of F. gigantica from China, Indonesia and Japan, the isolate from China with significant bootstrap values being the closest. ITS2 sequence motifs allowed an accurate in silico distinction of liver flukes. The data indicate that ITS2 motifs (

Theoretical Investigation of the Interaction between Fluorinated Dimethyl Ethers (nF ) 1-5) and Water: Role of the Acidity and Basicity on the Competition between OH ··· O and CH ··· O Hydrogen Bonds

Abstract: Theoretical calculations have been carried out using ab initio MP2 and B3LYP density functional methods to investigate the interaction between fluorinated dimethyl ethers (nF = 1-5) and water. Depending on the number of F atoms implanted on the dimethyl ethers, linear structures stabilized by intermolecular O(w)H(w)...O or CH...O(w) hydrogen bonds or closed structures involving both hydrogen bonds are formed. Binding energies of the hydrogen-bonded complexes range between 4 and 12 kJ mol(-1). Blue shifts of the CH stretching vibrations are predicted even in the absence of a direct CH...O interaction. The red shifts of the OH stretching vibrations of water in the open and closed structures are analyzed as well. The natural bond orbital analysis includes the sigma*(O(w)H(w)) and sigma*(CH) occupation, the hybridization of the C atom, the atomic charges, and the intra- and intermolecular hyperconjugation energies. These parameters are discussed as a function of the proton affinity (PA) of the O atom and the deprotonation enthalpy (DPE) of the CH bonds of the fluorinated ethers calculated in a previous work. (16) Our results show that the effective PA in determining the intermolecular O --> sigma*(O(w)H(w)) hyperconjugation energies decreases with increasing acidity of the CH bond. In turn, the effective acidity of the CH bond in determining the intermolecular O(w) --> sigma*(CH) hyperconjugation energies decreases with increasing basicity of the O atom.

Therapeutic efficacy of Zanthoxylum rhetsa DC extract against experimental Hymenolepis diminuta (Cestoda) infections in rats.

Abstract: Zanthoxylum rhetsa DC (Rutaceae), commonly called prickly ash, is used in the folk medicine of Naga tribes in India as a deworming remedy. In the present study, the therapeutic efficacy of Z. rhetsa leaf extract was investigated against experimental Hymenolepis diminuta (Cestoda) infections in albino rats. The efficacy of extract was determined on the basis of reduction in the eggs per gram of feces (EPG) counts and worm load following treatment with 100, 200, 400 and 800 mg/kg, p.o. doses of plant extract. For comparison’s sake, animals were also treated with a reference drug, praziquantel at 5 and 25 mg/kg body weight doses. Three treatment regimes were followed to monitor the effects of extract on cestode parasite: (1) Treatment on day 2–4 postinoculation (pi) of cysticercoids against the larval stages; (2) treatment on day 8–10 pi against the immature stages; and (3) treatment on day 21–25 pi against the adult stages of parasite. The extract revealed its maximum efficacy against the larval stage, where its 800 mg/kg dose showed a worm count reduction of 86.60%, compared to 80.00% by the reference drug, praziquantel (5 mg/kg dose). The EPG counts also decreased drastically from 23,389 ± 2,372 to 0 in the same treatment group, compared to 33,161 ± 1,383 recorded in the control group. The efficacy of extract was found to be of moderate level against the immature and adult stages of parasite. The present investigation holds the evidence that the leaves of Z. rhetsa possess significant anticestodal property and supports its use in folk medicine.

Ultrastructural observations on Fasciolopsis buski and its alterations caused by shoot extract of Alpinia nigra.

Abstract: The ultrastructural alterations in the tegument of Fasciolopsis buski in response to incubation in the alcoholic extract of Alpinia nigra were evaluated using transmission electron microscopy. The body tegument of the trematode is composed of an external syncytial layer, musculature, and an inner layer containing tegumental cells. The syncytium comprises various organelles like mitochondria, lysosomes, and tegumentary bodies of the type 2 kind with rare sighting of the type 1. Severe distortion and disorganization of the tegument was revealed in the parasite exposed to the A. nigra extract in the current study. The extent of vacuolization was such that vacuoles proceeded down to the basal lamina causing the syncytium to separate from the tegument at different places. There was depletion of parenchyma material and loss of connecting tubules running down from the syncytium to the tegumental cells causing the cells to be deprived of any proper boundaries. Microsc. Res. Tech., 2009. © 2008 Wiley-Liss, Inc.

A rigorous approach to the formulation of extended Born-Oppenheimer equation for a three-state system

Abstract: If a coupled three-state electronic manifold forms a sub-Hilbert space, it is possible to express the non-adiabatic coupling (NAC) elements in terms of adiabatic–diabatic transformation (ADT) angles. Consequently, we demonstrate: (a) Those explicit forms of the NAC terms satisfy the Curl conditions with non-zero Divergences; (b) The formulation of extended Born-Oppenheimer (EBO) equation for any three-state BO system is possible only when there exists coordinate independent ratio of the gradients for each pair of ADT angles leading to zero Curls at and around the conical intersection(s). With these analytic advancements, we formulate a rigorous EBO equation and explore its validity as well as necessity with respect to the approximate one (Sarkar and Adhikari, J Chem Phys 2006, 124, 074101) by performing numerical calculations on two different models constructed with different chosen forms of the NAC elements. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

Phytochemicals from Flemingia vestita (Fabaceae) and Stephania glabra (Menispermeaceae) alter cGMP concentration in the cestode Raillietina echinobothrida.

Abstract: Cyclic GMP (cGMP) mediates various physiological functions of nitric oxide (NO) synthesized by nitric oxide synthase (NOS) A crude peel extract and purified fraction of Flemingia vestita, as well as a crude rhizome extract of Stephania glabra and fractions were tested with respect to the activity of NOS, NO efflux and cGMP concentration in the cestode Raillietina echinobothrida in order to find out the possible mode of anthelmintic action of these plant-derived components For comparison purposes, the parasites were also treated with pure genistein, sodium nitroprusside (SNP-a known NO donor), and the reference drug, praziquantel (PZQ) At the time of onset of paralysis in the parasites, a significant increase (32%-87%) in the NOS activity and a two to three fold increase of NO efflux into the incubation medium were observed in the treated parasites in comparison to their respective controls The cGMP concentration in the treated parasites' tissue was also increased by 44%-103% However, in the presence of NG-nitro-L-arginine methyl ester, a potent inhibitor of NOS, there was no increase in the cGMP concentration in the parasite tissue This study indicates that the phytochemicals, in particular genistein and tetrahydropalmatine, from F vestita and S glabra, respectively, disturb the downstream signalling pathway of NO, as indicated by the change in cGMP concentration in the parasite tissue

Influence of glutathione levels on radiation-induced chromosomal DNA damage and repair in human peripheral lymphocytes

Abstract: Endogenous thiols, especially the tripeptide-reduced glutathione (GSH), are known to play an important role in cellular defense against radiation. However, there are evidences that suggest that GSH may not be an efficient protector of DNA. The present study will determine whether modulation of endogenous GSH levels protects or potentiates the amount of chromosomal damage induced by ionizing radiation (IR). Human lymphocytes were isolated and then treated with GSH (for 1 h) or buthionine sulfoximine (BSO; GSH-depleting agent for 5 h) before X-irradiation. DNA damage was analyzed by scoring chromosome aberrations (CAs) and by comet assay. The level of endogenous GSH was measured in lymphocytes treated with GSH, BSO or X-rays. A roughly 20% increase in endogenous GSH level was observed after a 3-h treatment with exogenous GSH and this reduced the frequency of all types of CA and aberrant metaphase chromosomes induced by 1 and 2 Gy of X-rays and also decreased the tail moment as determined by comet assay, suggesting radiation protection. Such uniform protection by GSH pretreatment was not visible while cells were exposed to 3 Gy or higher. Interestingly, in GSH-depleted lymphocytes, the frequency of radiation-induced CA was increased in a non-uniform manner. Therefore, an increase in the level of endogenous GSH in lymphocytes was unable to reduce chromosomal damage induced by 3 Gy or above, whereas decrease in the level of GSH enhanced the frequency of CA at all radiation doses in a non-uniform manner. It seems that GSH did not act as a radioprotector against DNA damage induced by higher dose X-rays rather it acts as a modulator of DNA repair activity.

Aggregation, adsorption, and clouding behaviors of Triton X-100 in formamide

Abstract: The critical micelle concentration (cmc) of TX-100 in formamide (FA) was determined from surface tension measurements as functions of temperature and NaCl concentration. At 25 degrees C, cmc was also determined by the fluorescence method. For the sake of comparison, micellization parameters of TX-100 were also determined in water. cmc, aggregation number, and standard free energy of micellization in FA are about 400 times higher, 10 times lower, and 2 times higher than in water, respectively. On increasing the temperature, cmc in FA shows a slight increase, whereas in water it decreases. The logarithm of relative cmc decreases linearly with added NaCl concentration in both FA and water, and the rate of this decrease is surprisingly equal in the two solvents. Micellization of TX-100 is exothermic in FA, but endothermic in water. The cloud point (CP) of TX-100 was determined in FA+water medium and that in pure FA was estimated to be approximately 233 degrees C when [TX-100]=0.15 mol kg(-1). Surface excess values of TX-100 were calculated from Gibbs and Langmuir adsorption isotherms. Values of standard free energy of adsorption calculated from the Rosen-Aronson equation and from the Langmuir adsorption isotherm are comparable. The ratio of the surface tension of the solvent to that at the cmc has been demonstrated as a novel scale for measuring solvophobicity.

High frequency plantlet regeneration from rhizomatous buds in Mantisia spathulata Schult. and Mantisia wengeri Fischer and analysis of genetic uniformity using RAPD markers.

Abstract: A protocol has been devised for enhanced in vitro regeneration of critically endangered Mantisia spathulata Schult. and Mantisia wengeri Fischer. Highest Bud Forming Capacity (BFC) of 6.10 +/- 0.55 with an average of 19.93 +/- 3.19 roots was obtained for M. spathulata within 5-6 weeks in Murashige and Skoogs (MS) medium supplemented with a combination of 10.0 microM of N6-benzyladenine (BA) and 2.5 microM of alpha-naphtalene acetic acid (NAA). For M. wengeri, BFC of 7.82 +/- 0.73 and 20.86 +/- 1.65 roots was achieved in MS media supplemented with a combination of 5.0 microM BA and 2.5 microM of NAA RAPD markers were used to evaluate the genetic stability of in vitro raised hardened plantlets. Similarity coefficient among the regenerated plants ranged between 0.85-0.98 for M. spathulata and 0.83-0.98 for M. wengeri. Maximum of 88 and 90% genetic similarity were obtained between in vitro raised hardened plantlets and mother stock of M. spathulata and M. wengeri, respectively through RAPD analysis. The hardened plantlets after RAPD analysis on being transferred to soil of experimental garden showed no marked phenotypic variations in vegetative or floral characteristics.

Composition, abundance and ecology of phytoplankton communities of Loktak Lake, Manipur, India

Abstract: Phytoplankton communities of Loktak Lake (a Ramsar site), studied during November 2002-October 2004, reveal the occurrence of 75 and 71 species, indicate monthly richness ranging between 47� plus or minus 6 and 49� plus or minus 3 species and record 50.0-83.2 and 64.5-84.0 % community similarities during two annual cycles respectively. Chlorophyta (33� plus or minus 5 and 35� plus or minus 5 species) show qualitative dominance and importance of Closterium > Cosmarium > Staurastrum > Micrasterias > Gonatozygon species. Phytoplankton (206� plus or minus 58 and 220� plus or minus 53 n/l) comprise between 45.1� plus or minus 6.5 and 42.9� plus or minus 5.8 % of net plankton abundance, indicate trimodal annual patterns and record peak abundance during winter. Chlorophyta (111� plus or minus 20 and 119� plus or minus 15 n/l), the dominant quantitative component, indicate winter peaks; Closterium > Staurastrum > Gonatozygon > Micrasterias species contribute significantly to their abundance. Ceratium hirudinella (43� plus or minus 52 and 39� plus or minus 37 n/l) is the sole important individual species of phytoplankton. Dinophyta > Bacillariophyta are sub-dominant groups and Euglenophyta > Cyanophyta > Chrysophyta show very low densities. Phytoplankton communities are characterized by higher species diversity, higher evenness and lower dominance. Abiotic factors register limited influence on richness and abundance of phytoplankton and on abundance of constituent groups. Multiple regression indicates relatively lower influence of fifteen abiotic factors on richness of phytoplankton and higher cumulative influence on abundance of phytoplankton, Chlorophyta, Dinophyta and Bacillariophyta.

Regeneration ecology and population status of a critically endangered and endemic tree species ( Ilex khasiana Purk.) in north-eastern India

Abstract: Detailed studies on population structure and regeneration ecology of Ilex khasiana were carried out at five representative natural populations i.e. Mylliem (Population - I), Upper Shillong (Population - II), Shillong Peak (Population - III), Laitkor (Population - IV) and Nongpiyur (Population - V) to probe into the responsible affecting factors for its population structure and regeneration ability in these populations. Experimental observation under three controlled light conditions (full sunlight (100%), intermediate sunlight (50%) and low sunlight (30%)) showed that the growth status and survival rates of seedlings under intermediate and low light were better than those under the high light condition. The density-diameter distribution in population of adult trees (≥5cm dbh) exhibited a typical character of a regenerating population. A higher seedling mortality rate in natural populations of I. khasiana was most probably due to increase in light intensity following vegetation destruction and other anthropogenic disturbances that cause opening of forest canopy. The findings of the present study would be of immense value in formulating appropriate conservation measures for the species.

On Solutions of a Class of Equations in a Finite Group

Abstract: Let G be a finite group and ω(x 1, x 2,…, x n ) denote the product of x 1, x 2,…, x n , in a randomly chosen order. The object of this article is to prove that the number of solutions of the equation ω(x 1, x 2,…, x n ) = g, with g ∊ G, defines a character of G.

Molecular characterization of Gastrodiscoides hominis (Platyhelminthes: Trematoda: Digenea) inferred from ITS rDNA sequence analysis

Abstract: Gastrodiscoides hominis (Digenea: Paramphistomata: Gastrodiscidae) is an amphistomid intestinal fluke of pigs causing gastrodiscoidiosis. With the use of molecular tools assisting the conventional diagnostic procedures, we aimed at finding out molecular characterization of G. hominis using PCR amplifications of rDNA ITS (1, 2) sequences. The sequences obtained (GenBank accession numbers EF027096, EF027097, EF027098, EU887294, and EU887295) were compared with available sequences of other digenean parasites, particularly those having a zoonotic potential in the northeastern region of India. The BLAST search revealed a close similarity with members of the family Paramphistomidae, showing maximum similarity with the amphistome, Homalogaster paloniae (subfamily Paramphistominae). Based on various tree construction methods, phylogeny of G. hominis is discussed.

p53-dependent antiproliferative and antitumor effect of novel alkyl series of diorganotin(IV) compounds

Abstract: Purpose: A series of diorganotin(IV) dichloride complexes of N-(2-pyridylmethylene)arylamine (nitrogen-chelating ligands) have been synthesized and characterized. The present study was carried out to investigate the comparative anti-proliferative and anti-tumor effect of Me2SnCl2.L1 (OTC-1), Et2SnCl2.L2 (OTC-2) and nBu2SnCl.L2 (OTC-3) in combination with X-rays (1.5 Gy). Method: The cytotoxicity of these diorganotin(IV) compounds was studied in human peripheral lymphocytes and the antitumor activity was assessed in Dalton’s lymphoma cells. The involvement of proteins that regulate cell cycle and apoptosis was investigated to elucidate the mechanism of their action. Results: 5 mg kg−1 of OTC-3 showed better antiproliferative and antitumor activity than OTC-1 and OTC-2, both as alone or in combination with X-rays. The maximum enhancement of exchange aberrations and the level of p53 and p16 proteins were observed in the OTC-3 treated samples. Upregulated expression of p53 caused a significant down-regulated transcriptionally repression of Survivin in OTC-3 treated human lymphocytes. Conclusion: It could be possible that after treatment with either OTC-3 alone or in combination with X-rays the Dalton’s lymphoma cells may die apoptotically after inducing initial delay in cell cycle and thereby survivality of mouse bearing Dalton’s Lymphoma cells was increased significantly.

Synthesis and structural characterization of manganese(III, IV) and ruthenium(III) complexes derived from 2-hydroxy-1-naphthaldehydebenzoylhydrazone

Abstract: Reaction of 2-hydroxy-1-naphthaldehydebenzoylhydrazone(napbhH2) with manganese(II) acetate tetrahydrate and manganese(III) acetate dihydrate in methanol followed by addition of methanolic KOH in molar ratio (2 : 1 : 10) results in [Mn(IV)(napbh)2] and [Mn(III)(napbh)(OH)(H2O)], respectively. Activated ruthenium(III) chloride reacts with napbhH2 in methanolic medium yielding [Ru(III)(napbhH)Cl(H2O)]Cl. Replacement of aquo ligand by heterocyclic nitrogen donor in this complex has been observed when the reaction is carried out in presence of pyridine(py), 3-picoline(3-pic) or 4-picoline(4-pic). The molar conductance values in DMF (N,N-dimethyl formamide) of these complexes suggest non-electrolytic and 1 : 1 electrolytic nature for manganese and ruthenium complexes, respectively. Magnetic moment values of manganese complexes suggest Mn(III) and Mn(IV), however, ruthenium complexes are paramagnetic with one unpaired electron suggesting Ru(III). Electronic spectral studies suggest six coordinate metal ions in t...