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61.
C. Mahendra KumarU.V. Sathisha Shylaja DharmeshA.G. Appu Rao Sridevi A. Singh 《Biochimie》2011,93(3):562-569
Sesamin, sesamolin (lignans) and sesamol - from sesame seed (Sesamum indicum L.) - are known for their health promoting properties. We examined the inhibition effect of sesamol, a phenolic degradation product of sesamolin, on the key enzyme in melanin synthesis, viz. tyrosinase, in vitro. Sesamol inhibits both diphenolase and monophenolase activities with midpoint concentrations of 1.9 μM and 3.2 μM, respectively. It is a competitive inhibitor of diphenolase activity with a Ki of 0.57 μM and a non-competitive inhibitor of monophenolase activity with a Ki of 1.4 μM. Sesamol inhibits melanin synthesis in mouse melanoma B16F10 cells in a concentration dependant manner with 63% decrease in cells exposed to 100 μg/mL sesamol. Apoptosis is induced by sesamol, limiting proliferation. This study of the chemistry and biology of lignans, in relation to the mode of action of bioactive components, may open the door for drug applications targeting enzymes. 相似文献
62.
Vaddadi Sridevi Parvatam Giridhar 《Journal of plant biochemistry and biotechnology.》2014,23(1):112-118
Direct differentiation of shoot buds in Coffea dewevrei was evident from the seedling shoots with collar region and also from collar region end of hypocotyl segments in presence of 40 μM AgNO3, 8.88 μM of BA and 2.85 μM of IAA. Apart from this, shoot end of hypocotyl explants mainly supported yellow friable callus or somatic embryos. Subsequent transfer to the same medium induced secondary somatic embryogenesis. The collar region of the hypocotyl explants not only showed direct organogenesis by producing 1–3 shoots per explant and also able to produce globular somatic embryos and embryogenic yellow friable callus. Similarly direct somatic embryogenesis along with yellow friable embryogenic callus formation on 1/2 strength MS medium comprising 1.47 μM IAA, 2.22 μM BA and 40 μM AgNO3 was noticed from cut portion of in vitro leaf and stalk of regenerated plants. The microshoots rooted well upon subculturing onto the same medium in 6 weeks and showed 60 % survival in green house and resumed growth upon hardening. 相似文献
63.
Ajit Thachil Sridevi Chennapragada Narasimhan Calambur 《Indian pacing and electrophysiology journal》2014,14(3):161-164
Tachycardia detection and therapy algorithms in Implantable Cardioverter-Defibrillators (ICD) reduce, but do not eliminate inappropriate ICD shocks. Awareness of the pros and cons of a particular algorithm helps to predict its utility in specific situations. We report a case where PR logic™, an algorithm commonly used in currently implanted ICDs to differentiate supraventricular tachycardia (SVT) from ventricular tachycardia resulted in inappropriate detection and shock for an SVT, and discuss several solutions to the problem. 相似文献
64.
Polyamines are essential compounds for growth and development in plants. An attempt has been made to find out the endogenous
polyamine profiles in various parts and during the ontogeny of fruit formation of two commercially important Coffea species viz., arabica and canephora. Putrescine (Put), spermine (Spm) and spermidine (Spd) are the predominant polyamines during the ontogeny of fruit and their
level increased with the advancement of fruit development. However, in the initial stages of flower and fruit development
Spm levels were found to be decreased. Elevated levels of major polyamines Put, Spd, and Spm were observed in zygotic embryos
than in somatic embryos. Along with this cadavarine (Cad) and other biogenic amines viz., tyramine (Tyr) and tryptamine (Try)
were also found during the ontogeny of fruit in C. canephora. In this study the enodogenous polyamine profiles in coffee tissues and beans have been addressed. 相似文献
65.
G. Veeranagamallaiah G. S. Ranganayakulu M. Thippeswamy M. Sivakumar K. Eswaranarayana Reddy M. Pandurangaiah V. Sridevi Chinta Sudhakar 《Plant Growth Regulation》2009,59(2):137-143
Salt stress is a major environmental factor in arid and semi-arid regions and influences many aspects of plant development.
Salinity results in generation of various free radicals that can potentially damage the cellular constituents in plants. Plants
were able to effectively reduce the damage caused by these free radicals by a way of enzymatic and non enzymatic defenses
for better survival. Enhanced efficacy of antioxidative enzyme systems such as superoxide dismutase, catalase and ascarbate
peroxidase was well documented in several plants subjected to salinity stress. Aldose reductase, an important enzyme is also
known to detoxify free toxic aldehydes like HNE (4-hydroxynon-2-enal, a hydroxyalkenal) generated during oxidative damage
of cellular components. However, the role of aldose reductase to impart tolerance to the plants under salt stress has not
been studied in any detail. Therefore, we were interested to study the aldose reductase activity and its expression to gain
an insight into the role of aldose reductase in imparting tolerance to foxtail millet cultivars (viz., Cv. Prasad and Lepakshi)
subjected to NaCl stress. We observed that subjecting foxtail millets to increasing levels of stress significantly increased
aldose reductase activity and in a way that correlated positively with elevated levels of sorbitol, an osmotic solute involved
in osmotic balance. This suggests the involvement of aldose reductase in sorbitol biosynthesis in foxtail millet. Additionally,
we observed higher levels of 4-hydroxynon-2-enal, a major lipid peroxidation product, in the susceptible than the tolerant
cultivar indicating a higher proportion of cellular damage in former than in the latter. This high content of 4-hydroxynon-2-enal
in the susceptible cultivar was negatively correlated with its aldose reductase activity, indicating the involvement of aldose
reductase in detoxification of 4-hydroxynon-2-enal. 4-hydroxynon-2-enal is also known to be a catalyzed by glutathione-S-transferase. Glutathione-S-transferase activity was found higher in the tolerant foxtail millet than the sensitive cultivar: the tolerant cultivar showed
a low 4-hydroxynon-2-enal content compared to the susceptible cultivar, demonstrating a possible mechanism for detoxification
of 4-hydroxynon-2-enal by two enzymes, glutathione-S-transferase and aldose reductase in plants under stressful conditions. 相似文献
66.
Potent induction of Arabidopsis thaliana flowering by elevated growth temperature 总被引:2,自引:0,他引:2 下载免费PDF全文
The transition to flowering is an important event in the plant life cycle and is modulated by several environmental factors including photoperiod, light quality, vernalization, and growth temperature, as well as biotic and abiotic stresses. In contrast to light and vernalization, little is known about the pathways that mediate the responses to other environmental variables. A mild increase in growth temperature, from 23 °C to 27 °C, is equally efficient in inducing flowering of Arabidopsis plants grown in 8-h short days as is transfer to 16-h long days. There is extensive natural variation in this response, and we identify strains with contrasting thermal reaction norms. Exploiting this natural variation, we show that FLOWERING LOCUS C potently suppresses thermal induction, and that the closely related floral repressor FLOWERING LOCUS M is a major-effect quantitative trait locus modulating thermosensitivity. Thermal induction does not require the photoperiod effector CONSTANS, acts upstream of the floral integrator FLOWERING LOCUS T, and depends on the hormone gibberellin. Analysis of mutants defective in salicylic acid biosynthesis suggests that thermal induction is independent of previously identified stress-signaling pathways. Microarray analyses confirm that the genomic responses to floral induction by photoperiod and temperature differ. Furthermore, we report that gene products that participate in RNA splicing are specifically affected by thermal induction. Above a critical threshold, even small changes in temperature can act as cues for the induction of flowering. This response has a genetic basis that is distinct from the known genetic pathways of floral transition, and appears to correlate with changes in RNA processing. 相似文献
67.
TNF-Related Apoptosis Inducing Ligand (TRAIL) binds to and activates death receptors to stimulate caspase-8 and apoptosis with higher efficiency in cancer than normal cells but the development of apoptosis resistance has limited its clinical efficacy. We found that stable, but not transient knockdown of the ABL tyrosine kinase enhanced the apoptotic response to TRAIL. Re-expression of Abl, but not its nuclear import- or kinase-defective mutant, in the ABL-knockdown cells re-established apoptosis suppression. TRAIL is known to stimulate caspase-8 ubiquitination (Ub-C8), which can facilitate caspase-8 activation or degradation by the lysosomes. In the ABL-knockdown cells, we found a higher basal level of Ub-C8 that was not further increased by lysosomal inhibition. Re-expression of Abl in the ABL-knockdown cells reduced the basal Ub-C8, correlating with apoptosis suppression. We found that lysosomal inhibition by chloroquine (CQ) could also enhance TRAIL-induced apoptosis. However, this pro-apoptotic effect of CQ was lost in the ABL-knockdown cells but restored by Abl re-expression. Interestingly, kinase inhibition at the time of TRAIL stimulation was not sufficient to enhance apoptosis. Instead, persistent treatment for several days with imatinib, an ABL kinase inhibitor, was required to cause the enhanced and the CQ-insensitive apoptotic response to TRAIL. Together, these results show that persistent loss of nuclear ABL tyrosine kinase function can sensitize cells to TRAIL and suggest that long-term exposure to the FDA-approved ABL kinase inhibitors may potentiate apoptotic response to TRAIL-based cancer therapy. 相似文献
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69.
Ramar Thangam Palani Gunasekaran Krishnasamy Kaveri Gnanaiah Sridevi Shenbagamoorthy Sundarraj Manickam Paulpandi Soundarapandian Kannan 《Process Biochemistry》2012,47(8):1243-1249
Animal venoms and toxins are potential bioresources that have been known to mankind as a therapeutic tool for more than a century through folk and traditional medicine. The purified “disintegrin protein” (64 kDa) from the venom of the Indian cobra snake (Naja naja) exhibited cytotoxic effects of various types of human cancer cell lines such as breast cancer (MCF-7), lung cancer (A549) and liver cancer (HepG2). In vitro cytotoxicity, DNA fragmentation, an apoptotic assay and a cell cycle analysis were performed to evaluate the anticancer activity of disintegrin against the above cell lines. The IC50 value of disintegrin was determined to be 2.5 ± 0.5 μg/mL, 3.5 ± 0.5 μg/mL, and 3 ± 0.5 μg/mL for the MCF-7, A549 and HepG2 cell lines respectively. Moreover, the increased distribution of G0/G1 and S phase led to decreased populations of cells in the G2/M phase of MCF-7, HepG2 and A549 cells. 相似文献