Iodine treatment (dose-response, time course)

The number and type of synthetic chemicals that are being produced worldwide continues to increase significantly. While these industrial chemicals provide numerous benefits, there is no doubt that some have potential to damage the environment and health. Toxicity must be evaluated and use must be carefully controlled and monitored in order to minimize potential damage. DNA microarray technology has become an important new technique in toxicology. We are using the yeast Saccharomyces cerevisiae as a model organism for toxicological study because it is a simple, fast-growing eukaryote that has been thoroughly characterized. In order to evaluate toxicity by newly synthesized or mixture chemicals, toxicity-induced gene expression alteration profiles by known chemicals should be collected. In our study, cells need to be exposed with same experimental cellular condition, semi lethal (IC50), respectively. In the case of iodine (CAS; 7553-56-2), the IC50 was 1 mM by growth curve with continuously diluted exposure. // Effects of Iodine on Global Gene Expression in Saccharomyces cerevisiae : It is well documented that iodine kills microorganisms with broad spectrum. However, a systematic study of its mechanism of action has not yet been reported. Here we have demonstrated the action of iodine on gene expression level, using the yeast Saccharomyces cerevisiae with a DNA microarray. It was found that like antimicrobial activity, iodine causes an immediate and dose-dependent (0.5 mM, 0.75 mM and 1 mM) transcriptional alteration on yeast cells. The effects of iodine continued after the first immediate response. Genes for C-compound and carbohydrate metabolism, for energy, and for cell rescue were continuously up-regulated. On the other hand, genes related to protein fate were induced especially at 0.5 h. The gene expression profile at 0.5 h was significantly different from other longer iodine exposed condition. The main reaction at 0.5 h after iodine addition may be due to the oxidative toxicity, and the profile at 0.5 h was similar to agricultural bactericide. Keywords: stress response In each condition except the data at 2.5 h, there are 2 hybridization results from independent biological samples, respectively. The data at 2.5 h has one hybridization data, only. 2nd hybridization in dose-response experiments and both hybridization in all time course experiments have high and low power scanned data, respectively. On the other hand, 1st hybridization in dose-response experiments have single scanned data.