Plumbagin Inhibits Proliferative and Inflammatory Responses of T Cells Independent of ROS Generation But by Modulating Intracellular Thiols

Plumbagin inhibited activation, proliferation, cytokine production, and graft-versus-host disease in lymphocytes and inhibited growth of tumor cells by suppressing nuclear factor-kappa B (NF-kappa B). Plumbagin was also shown to induce reactive oxygen species (ROS) generation in tumor cells via an unknown mechanism Present report describes a novel role of cellular redox in modulation of immune responses in normal lymphocytes by plumbagin. Plumbagin depleted glutathione (GSH) levels that led to increase in ROS generation The decrease in GSH levels was due to direct reaction of plumbagin with GSH as evinced by mass spectrometric and HPLC analysis. Further, addition of plumbagin to cells resulted in decrease in free thiol groups on proteins and increase in glutathionylation of proteins. The suppression of mitogen-induced T-cell proliferation and cytokine (IL-2/IL-4/IL-6/IFN-gamma) production by plumbagin was abrogated by thiol antioxidants but not by non-thiol antioxidants confirming that thiols but not ROS play an important role in biological activity of plumbagin. Plumbagin also abrogated mitogen-induced phosphorylation of ERK, IKK, and degradation of I kappa B-alpha However, it did not affect phosphorylation of P38, JNK, and AKT. Our results for the first time show that antiproliferative effects of plumbagin are mediated by modulation of cellular redox These results provide a rationale for application of thiol-depleting agents as anti-inflammatory drugs J. Cell Biochem. 110: 1082-1093, 2010. (C) 2010 Wiley-Liss. In

Genetic analysis of dormancy and shattering traits in the backcross inbred lines derived from Oryza sativa cv. Swarna / O. nivara Ac. CR100008

Seed dormancy and shattering are important traits influencing the economics of rice farming. The genetic basis of dormancy and shattering traits were investigated in 174 Backcross Inbred Lines (BILs) derived from Oryza sativa cv. Swarna and O. nivara ac. CR100008. Significant variation was observed among the BILs for dormancy and shattering traits. Dormancy of 4-40 days was observed among BILs harvested at 35 days after heading and all the BILs attained &gt; 80% germination by 6th week. Among all the BILs, least dormancy period (4 days) was found in SN-1, 13, 23, 25 and SN-28. Highest dormancy period (40 days) was found in 4 BILs i.e., SN-108, SN-116, SN-117 and SN-122 (40 days). None of the BILs were found to have non-shattering trait, while 2 BILs (SN-38 and SN-163) showed low shattering and 18 BILs were found with very high grain shattering percent. Of the 312 SSRs screened, 94 were polymorphic between the parents. A strategy of combining the DNA pooling from phenotypic extremes and genotyping was employed to detect the putative markers associated with dormancy and shattering traits. Single marker analysis revealed co-segregation of two putative markers RM488 on chromosome 1 and RM247 on chromosome 12 were with dormancy and shattering traits respectively. The putative marker RM488 identified is suitable for the marker-assisted transfer of the dormancy shown by O. nivara accession CR100008 for addressing pre harvest sprouting in modern cultivars. Interestingly, O. nivara type allele at RM247 was observed in BILs with low shattering phenotype.</jats:p

Benzene metabolites enhance reactive oxygen species generation in HL60 human leukemia cells

Human and Experimental Toxicology155422-427HETO