AdoMet plays numerous roles of being the major methyl-group donor in trans-methylation reactions. To gain insight into the possible functions of the AdoMet protein of Suaeda salsa L. in response to salt stress, S aden...AdoMet plays numerous roles of being the major methyl-group donor in trans-methylation reactions. To gain insight into the possible functions of the AdoMet protein of Suaeda salsa L. in response to salt stress, S adenosylmethionine synthetase gene (SAMS2) was analyzed. We isolated SAMS2 cDNA clone (AF321001) from a lambda -Zap cDNA library constructed from the halophyte S. salsa Pall aerial tissue treated with 400 mmol/L NaCl. SsSAMS2 was found to encode a S-adenolyl-L-methionine synthetase enzyme (AdoMet synthetase). The fragment was 1 531 bp with an open reading frame of 395 amino acids, the calculated molecular weight was about 43 kD. SsSAMS2 showed the highest homology to SAMS2 gene of Catharanthus roseus G. Don., with 93% identity in deduced amino acid sequence. Southern blotting analysis showed that SsSAMS2 might be a two-copy gene in S. salsa genome. Northern blot indicated that the cDNA was up-regulated by salt and other stresses. Enzyme activity assay indicated that the activity of SAMS2 increased under NaCl stress.展开更多
S-Adenosyl-L-Methionine (AdoMet), S-Adenosyl- L-Homocysteine (AdoHcy), adenosine, trehalose and oleanolic acid were measured in six medicinal herbs and three spices. The findings showed that AdoMet content was forty s...S-Adenosyl-L-Methionine (AdoMet), S-Adenosyl- L-Homocysteine (AdoHcy), adenosine, trehalose and oleanolic acid were measured in six medicinal herbs and three spices. The findings showed that AdoMet content was forty six fold higher in the leaves of Catharanthus roseus as compared with average AdoMet content of rest of the plants. In comparison to other plants, Withania somnifera had very high AdoHcy: Ado-Met and adenosine: AdoMet ratios indicating it may have contained high AdoMet. Trehalose was found to be twenty fold and nine fold higher in bulb of Allium cepa and root of Withania somnifera respectively with respect to average trehalose content of rest of the plants. Ocimum sanctum appeared to be a rich source of oleanolic acid. It appeared from our study that Catharanthus roseus, Allium cepa and Ocimum sanctum could be utilized as natural sources of AdoMet, trehalose and oleanolic acid respectively.展开更多
Objective: To investigate the gene regulation of taxolinduced apoptosis Methods: Northern blot hybridization, enzyme activity assay of S AdoMet synthetase and flow cytometry were performed in the investigation of ex...Objective: To investigate the gene regulation of taxolinduced apoptosis Methods: Northern blot hybridization, enzyme activity assay of S AdoMet synthetase and flow cytometry were performed in the investigation of expression in the mRNA level and biological action of S AdoMet synthetase in taxol induced apoptosis in human breast cancer cell line (BCap 37) Results: Up regulation of S AdoMet synthetase expression was resulted by taxol treatment and the expression peaked at 48 hours Moreover,the up regulation of S AdoMet synthetase was associated with cytotoxicity of anti microtubule agents including taxol and colchicine Inhibition rate of S AdoMet synthetase activity by 1% DMSO was 34% in taxol treated cells and 14% in taxol untreated cells compared to control groups, respectively Posttreatment with 1% DMSO following pretreatment with individual antitumor agent for 3 hrs promoted apoptotic cell death of taxol ,colchicine ,and adriamycin treated Bcap37 cells Conclusion : The induction of apoptosis enhanced by post treatment with DMSO in taxol treated cells is probably linked to its inhibition on enzyme activity of S AdoMet synthetase ,suggesting that the increased expression of S AdoMet synthetase possibly plays an important role in protecting cells from DNA fragmentation in taxol induced apoptosis Accepted July 26, 1998 This work was supported by the National High Biotechnology Foundation of China and a grant from the Natural Science Foundation of Zhejiang Province, China展开更多
文摘AdoMet plays numerous roles of being the major methyl-group donor in trans-methylation reactions. To gain insight into the possible functions of the AdoMet protein of Suaeda salsa L. in response to salt stress, S adenosylmethionine synthetase gene (SAMS2) was analyzed. We isolated SAMS2 cDNA clone (AF321001) from a lambda -Zap cDNA library constructed from the halophyte S. salsa Pall aerial tissue treated with 400 mmol/L NaCl. SsSAMS2 was found to encode a S-adenolyl-L-methionine synthetase enzyme (AdoMet synthetase). The fragment was 1 531 bp with an open reading frame of 395 amino acids, the calculated molecular weight was about 43 kD. SsSAMS2 showed the highest homology to SAMS2 gene of Catharanthus roseus G. Don., with 93% identity in deduced amino acid sequence. Southern blotting analysis showed that SsSAMS2 might be a two-copy gene in S. salsa genome. Northern blot indicated that the cDNA was up-regulated by salt and other stresses. Enzyme activity assay indicated that the activity of SAMS2 increased under NaCl stress.
文摘S-Adenosyl-L-Methionine (AdoMet), S-Adenosyl- L-Homocysteine (AdoHcy), adenosine, trehalose and oleanolic acid were measured in six medicinal herbs and three spices. The findings showed that AdoMet content was forty six fold higher in the leaves of Catharanthus roseus as compared with average AdoMet content of rest of the plants. In comparison to other plants, Withania somnifera had very high AdoHcy: Ado-Met and adenosine: AdoMet ratios indicating it may have contained high AdoMet. Trehalose was found to be twenty fold and nine fold higher in bulb of Allium cepa and root of Withania somnifera respectively with respect to average trehalose content of rest of the plants. Ocimum sanctum appeared to be a rich source of oleanolic acid. It appeared from our study that Catharanthus roseus, Allium cepa and Ocimum sanctum could be utilized as natural sources of AdoMet, trehalose and oleanolic acid respectively.
文摘Objective: To investigate the gene regulation of taxolinduced apoptosis Methods: Northern blot hybridization, enzyme activity assay of S AdoMet synthetase and flow cytometry were performed in the investigation of expression in the mRNA level and biological action of S AdoMet synthetase in taxol induced apoptosis in human breast cancer cell line (BCap 37) Results: Up regulation of S AdoMet synthetase expression was resulted by taxol treatment and the expression peaked at 48 hours Moreover,the up regulation of S AdoMet synthetase was associated with cytotoxicity of anti microtubule agents including taxol and colchicine Inhibition rate of S AdoMet synthetase activity by 1% DMSO was 34% in taxol treated cells and 14% in taxol untreated cells compared to control groups, respectively Posttreatment with 1% DMSO following pretreatment with individual antitumor agent for 3 hrs promoted apoptotic cell death of taxol ,colchicine ,and adriamycin treated Bcap37 cells Conclusion : The induction of apoptosis enhanced by post treatment with DMSO in taxol treated cells is probably linked to its inhibition on enzyme activity of S AdoMet synthetase ,suggesting that the increased expression of S AdoMet synthetase possibly plays an important role in protecting cells from DNA fragmentation in taxol induced apoptosis Accepted July 26, 1998 This work was supported by the National High Biotechnology Foundation of China and a grant from the Natural Science Foundation of Zhejiang Province, China
