ArsA is the catalytic component of an arsenite extrusion pump in E. coli that confers arsenite and antimonite resistance. YDL100cp is the ArsA homologous protein found in S. cerevisiae. Previous studies show that YDL100c gene is not directly related to arsenical resistance mechanism in S. cerevisiae but the YDL100c disrupted strain (KO) showed sensitivity to Zn2+ at 30oC and more pronounced sensitivity at 37oC. To study the role of YDL100c on Zn2+ sensitivity, wild type strain (WT) and KO were grown at 30oC and 37oC for 6 hr after adding Zn2+. Both strains were assayed for trehalose accumulation, intracellular oxidation level and GSH content. The results demonstrate that KO had a decreased growth and increased intracellular oxidation at 37oC when compared to WT. Addition of Zn2+ did not increase the intracellular oxidation in WT and KO grown at 30oC but to a greater extent in KO compared to WT grown at 37oC. Further assess the function of antioxidant genes shows that there is no significant difference in SOD1 expression between KO and WT grown at 37oC but CTT1 expression is low in KO. There is an increase in catalase activity for both WT and KO by adding Zn2+ at 30oC or 37oC, but the level of catalase activity to KO is still lower than that of WT.In conclusion, a defect of YDL100c results in a defect in the activation of general stress response at 37oC. Consequently, the cause of the increased level of intracellular oxidation of KO in the presence of Zn2+ grown at 37oC is most likely related to the decrease in cellular GSH content and trehalose accumulation in KO compared to that of WT. Therefore, the pronounced sensitivity to Zn2+ at 37oC is mainly due to a defect in general stress response in KO when grown at 37oC.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0808108-102949 |
| Date | 08 August 2008 |
| Creators | Shih, Yi-Ju |
| Contributors | Zin-Huang Liu, Ching-Mei Hsu, Jong-Kang Liu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0808108-102949 |
| Rights | campus_withheld, Copyright information available at source archive |
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