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Kolkata, India

Mukhopadyay M.,North Bengal Agricultural University | Mukhopadyay M.,Kalyani University | Bantawa P.,North Bengal Agricultural University | Das A.,North Bengal Agricultural University | And 5 more authors.
BioMetals | Year: 2012

Tea [Camellia sinensis (L.) O. Kuntze] is an aluminum (Al) hyperaccumulator plant and is commercially important due to its high content of antioxidants. Although Al induced growth is wellknown for the plants growing in acid soil, yet the cause underlying the stimulatory effect of Al has not been fully understood. To investigate the possible role of Al in growth induction, we studied morphological, physiological as well as biochemical changes of tea plant under different Al concentrations (0-4,000 μM). In hydroponics, Al (15 μM), enhanced shoot and root growth, but at higher concentrations, it caused oxidative damage which culminated in a cascade of biochemical changes, Al content increased concurrently with the maturity of the leaf as well as stem tissues than their younger counterparts. Hematoxylin staining indicated that Al accumulation started after 6 h of exposure in the tips of young roots and accumulation was dose dependent. The physiological parameters such as pigments, photosynthetic rate, transpiration and stomatal conductance were declined due to Al toxicity. Alteration in activated oxygen metabolism was also evidenced by increasing lipid peroxidation, membrane injury, evolution of superoxide anions and accumulation of H2O2. Contents of phenols initially exhibited an acceleration which gradually plummeted at higher levels whereas total sugar and starch contents decimated beyond 15 μM of Al concentration. Activities of antioxidant defense enzymes were increased with the elevated concentration of Al. Expression of citrate synthase gene was upregulated in the mature leaves, young as well as old roots simultaneously with increased concentration of Al in those parts; indicating the formation of Al-citrate complex. These results cooperatively specified that Al concentration at lower level promoted growth but turned out to be a stressor at elevated stages indicating the sensitivity of the cultivar (T-78) to Al. Copyright © Springer Science+Business Media, LLC. 2012. Source

Basu Majumder A.,Tea Board of India | Hath T.K.,North Bengal Agricultural University
Journal of Biopesticides | Year: 2012

The efficacy of some bio-rational insecticides against tea looper complex, Hyposidra spp. was evaluated at two different locations of Dooars tea plantations, West Bengal. The results indicated that all the insecticides were effective in reducing the looper population to a significant level. However, in comparison to other insecticides, neem based insecticides could not give the desired level of control. Among the different treatments, diflubenzuron 25 WP @ 700g/ha caused maximum reduction of loopers over control in both the sprayings at both the locations [Location I: 66.91% and 65.54% reduction of loopers at 7 days after 1st and 2nd spraying respectively) and Location II: 68% and 50.85% reduction of loopers at 7 days after 1st and 2nd spraying respectively)] and appeared to be the best treatment against loopers. Bt-k @ 1000 mL/ha was the next best treatment for suppressing looper population at 7 days after 1st spraying (64.44% and 67.81% reduction of loopers at Location I and II respectively) which was at par with recommended insecticide deltamethrin 2.8 EC @ 200 mL/ha (65.14% and 62.16% reduction of loopers at Location I and II respectively). However, in 2nd spraying, its efficacy was declined. Both the doses of Neem based insecticides recorded 31-49% reduction of loopers after 1st spraying but this was reduced only to 9-17% after 2nd spraying, Thus, in consideration of the performance of the insecticides, diflubenzuron @700 g/ha and Bt-k @ 1000 mL/ha could be included in the IPM package of looper. Source

Mandal S.,Indian Institute of Science | Mukhopadhyay S.,Indian Institute of Science | Bandhopadhyay S.,Indian Institute of Science | Sen G.,Tea Board of India | Biswas T.,Indian Institute of Science
Alcohol | Year: 2014

Andrographis paniculata (AP) is a traditional medicinal plant of Ayurveda. It grows widely in Asia and isprescribed in the treatment of liver diseases. Here we have investigated the beneficial role of 14-deoxyandrographolide (14-DAG), a bioactive diterpenoid from AP, against alcoholic steatosis in rats. 14-DAG was extracted from aerial parts (leaves and stems) of AP. Rats were fed with ethanol for 8 weeks. Animals were treated with 14-DAG during the last 4 weeks of ethanol treatment. Invitro studies were undertaken in a human hepatocellular liver carcinoma cell line culture. Hepatosteatosis was assessed from histopathological studies of liver sections. Acetyl-CoA, malonyl-CoA, and triglyceride contents were determined using commercially available kits. Fatty acid synthesis was evaluated from incorporation of 1-14C acetate. Regulation of fatty acid oxidation and lipogenesis were monitored with immunoblotting and immunoprecipitation studies. Ethanol exposure led to hepatotoxicity, as evident from the marked enhancement in the levels of AST and ALT. The values decreased almost to control levels in response to 14-DAG treatment. Results showed that ethanol feeding induced deactivation of AMP-activated protein kinase (AMPK) that led to enhanced lipid synthesis and decreased fatty acid oxidation, culminating in hepatic fat accumulation. Treatment with 14-DAG activated AMPK through induction of cyclic AMP-protein kinase A pathway. Activation of AMPK was followed by down-regulation of sterol regulatory element binding protein-1c, acetyl-CoA carboxylase, and fatty acid synthase, leading to suppression of lipogenesis. This was associated with up-regulation of sirtuin 1 and depletion of malonyl-CoA, in favor of increased fatty acid oxidation. 14-DAG controlled ethanol-induced hepatosteatosis by interfering with dysregulation of lipid metabolism. In conclusion, our results indicated that 14-DAG was capable of preventing the development of fatty liver through AMPK-mediated regulation of lipid metabolism. This finding supported the hepatoprotective role of 14-DAG, which might serve as a therapeutic option to alleviate hepatosteatosis in chronic alcoholism. © 2014 Elsevier Inc. Source

Dasgupta N.,Indian Statistical Institute | Biswas P.,Darjeeling Tea Research and Development Center | Kumar R.,Darjeeling Tea Research and Development Center | Kumar N.,Darjeeling Tea Research and Development Center | And 2 more authors.
Physiology and Molecular Biology of Plants | Year: 2013

Ten Darjeeling tea clones (BT15/263, RR17/144, B777, T253, B157, Sundaram, HV39, AV2, K1/1 and TTV1) were collected from the experimental garden of Darjeeling Tea Research and Development Centre, Kurseong. Total phenol, flavonoids and two antioxidating enzymes (peroxidase and superoxide dismutase) were estimated. The total phenol ranged between 241 and 28 GAE mg g-1 of leaf dry weight. The highest amount obtained in four clones, B15/263 (241.47), RR17/144 (221.2), B777 (154.54) and B157 (140.23 mg g-1). Flavonoids were estimated as Catechin equivalent (CE) and ranged between 56.88 and 20.81 CE mg g-1 leaf dry weight. Higher amounts occurred in BT15/263 (56.88 mg g-1), B777 (56.69) and RR17/144 (48.63). Antioxidant activities were measured following DPPH and ABTS free radicle scavenging procedures and the results were well according to total polyphenol content among the clones (in total phenols, ranges of correlation in DPPH assay were r2 = 0.990-0.989, p ≤ 0.05; in flavonoids r2 = 0.954, p ≤ 0.01-0.987, p ≤ 0.05). Similarly, ABTS percent scavenging results were quiet significant. The IC50 values were determined for both DPPH and ABTS assay. PAGE expressions of isoforms in two antioxidative enzymes and quantification of them also varied much among the investigated clones. The incidence of total phenols, flavonoids, PRX and SOD and ROS scavenging assay in in-situ condition, might be used as biochemical markers towards the superior adaptability against abiotic stress. In the present work, four clones (B15/263, B777, RR17/144 and B157) would be designated as comparatively better suited to the predicted abiotic stress. © 2013 Prof. H.S. Srivastava Foundation for Science and Society. Source

Raina S.N.,University of Delhi | Raina S.N.,Amity University | Ahuja P.S.,Institute of Himalayan Bioresource Technology | Sharma R.K.,Institute of Himalayan Bioresource Technology | And 32 more authors.
Genetic Resources and Crop Evolution | Year: 2012

The most important evolutionary event in the success of commercial tea cultivation outside China in ~30 countries came about by the origin of India hybrid tea in India, derived from the extensive spontaneous hybridization that took place between the Assam type tea growing in the forest regions of Assam, North-East India and China type tea introduced from China in ~1875 to many regions of North-East India. The release of an enormous pool of vigorous and highly variable plants of India hybrid tea in North-East India was a significant step forward for the origin and evolution of tea as a highly successful crop plant. The 1,644 accessions and clones of India hybrid tea, representatives of known 15 morphotypes, were screened by 412 AFLP markers amplified by 7 AFLP primer pair combinations. All the 412 genetic loci were polymorphic across the 1,644 accessions and clones. The analysis was done with distance (PCoA and NJ) methods, and the STRUCTURE (Bayesian) model. Both PCoA and NJ analysis clustered 1,644 tea accessions and clones into six major groups with one group in each, constituted mostly by China hybrid, Assam China hybrid and Assam hybrid morphotypes, of distinct genetic identity. No group was exclusive for any particular morphotype. The accessions and clones belonging to morphotypes, Assam type, Assam hybrid, China hybrid and China Cambod were distributed in all the groups. It is the Assam type/Assam hybrid morphotypes which exhibit much broader genetic variability than in China type/China hybrid/Cambod type/Cambod hybrid morphotypes. The STRUCTURE analysis inferred 16 populations (K = 16), for which the greatest values of probability were obtained. Nine of the 16 clusters were constituted by the tea accessions and clones of 'pure' ancestry. The remaining clusters were of 'mixed' ancestry. This analysis provides evidence that the accessions and clones of the same morphotype are not always of same genetic ancestry structure. The tea accessions and clones obtained from outside North-East India shared the same groups (distance method) and clusters (STRUCTURE model) which were constituted by North-East India accessions. The present study also demonstrates very narrow genetic diversity in the commercial tea clones vis-à-vis the profound genetic diversity existing in the tea accessions. These clones were distributed in hardly two of the six groups in NJ tree. The identified 105 core accessions and clones, capturing 98% diversity, have their origin from almost all groups/subgroups of NJ tree. © 2011 Springer Science+Business Media B.V. Source

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