Project description: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 round up (CAS; 40465-66-5), the exposure dose was decided as 1500 times dilution by growth curve with continuously diluted exposure. Roundup is the brand name of a systemic, broad-spectrum herbicide contains the active ingredient glyphosate. Glyphosate is classed as a moderately toxic herbicide and in EPA toxicity class III. // Genomic profile of roundup treatment of yeast using DNA microarray analysis: The herbicide Roundup, which contains glyphosate as the active ingredient, was first introduced in 1974 and has enjoyed widespread use in Japan and elsewhere in the world. Roundup-induced reactions occurring in the yeast Saccharomyces cerevisiae may have a predictive value for understanding responses in higher eukaryotes, and we applied yeast DNA microarray analysis for this purpose. Functional characterization of up-regulated open reading frames (ORFs) following Roundup treatment suggests that Roundup affects membrane structures and cellular organelles. Expression profiles induced by treatments with detergents, oils and hydrostatic pressure were similar to those following Roundup treatment based on cluster analysis. Glyphosate alone was not found to inhibit yeast growth at the concentration contained in the Roundup treatment used for microarray analysis. The toxicity of Roundup appeared to be due to detergent in the product. Keywords: stress response

Project description:Chronic obstructive pulmonary disease (COPD) is diagnosed by airway obstruction and underlies a group of ailments such as bronchitis, emphysema and often asthma; however, rodent models do not resemble human pathology. Because genetically predisposed spontaneously hypertensive (SH) rats display phenotypes such as systemic inflammation, thrombosis, oxidative stress, and suppressed immune function, that are also apparent in COPD patients, we exposed SH and commonly used male Sprague Dawley (SD) to 0, 250, or 350 ppm sulfur dioxide (SO2), 5h/d for 4 consecutive days. Airways disease was characterized by pulmonary functional, pathological and molecular analysis. SO2 caused dose-dependent changes in breathing parameters in both strains with SH rats being slightly more affected than SD. Bronchoalveolar lavage fluid (BALF) total cells and neutrophilic inflammation were dose-dependent and significantly greater in SH than in SD rats. The recovery was incomplete 4-day following SO2 exposure in SH rats. Pulmonary protein leakage did not occur in either strain but lactate dehydrogenase and n-acetyl glucosaminidase activity was increased in BALF of SH rats. Lung pathology and morphometric evaluation of mucin production in the airways demonstrated significantly greater impact of SO2 in SH than in SD rats. Baseline differences in lung gene expression pattern suggested marked immune dysregulation, oxidative stress, and impairment cell signaling and fatty acid metabolism in SH rats. Gene expression pattern of SD and SH rats following SO2 exposure demonstrated greater effect on inflammation/immune markers, and oxidative stress. Thus, the SH rat may serve as a better and more susceptible rat strain to be used for experimental model of bronchitis which is relevant to human disease. Experiment Overall Design: Spontaneously hypertensive and Sprague Dawley rats were used in this experiment. Each strain of rat was treated with either SO2 or AIR (control). There were 4 biological replicates for each strain/treatment.

Project description:Arsenic (As) exposure is a significant worldwide environmental health concern. Low dose, chronic arsenic exposure has been associated with higher risk of skin, lung, and bladder cancer, as well as cardiovascular disease and diabetes. While arsenic-induced biological changes play a role in disease pathology, little is known about the dynamic cellular changes due to arsenic exposure and withdrawal. In these studies, we seek to understand the molecular mechanisms behind the biological changes induced by chronic low doses of arsenic exposure. We used a comprehensive approach involving chromatin structural studies and mRNA microarray analyses to determine how chromatin structure and gene expression patterns change in response to chronic low dose arsenic exposure and its subsequent withdrawal. Our results show that cells exposed to low doses of sodium arsenite have distinct temporal and coordinated chromatin, gene expression and miRNA changes that are consistent with differentiation and activation of multiple biochemical pathways. Most of these temporal patterns in gene expression are reversed when arsenic was withdrawn. However, some of the gene expression patterns remained altered, plausibly as a result of an adaptive response by these cells. Additionally, these gene expression patterns correlated with changes in chromatin structure, further solidifying the role of chromatin structure in gene regulatory changes due to arsenite exposure. Lastly, we show that arsenite exposure influences gene regulation both at the transcription initiation as well as at the splicing level. Thus our results suggest that general patterns of alternative splicing, as well as expression of particular gene regulators, can be indicative of arsenite-induced cell transformation. A total of eight (8) samples with two biological replicates under four separate conditions: wild-type treated with deionized H2O for 36 days (NT); chronic low-dose arsenic exposure of 1 uM of sodium arsenite (iAs-T) for 36 days; chronic arsenic exposure of 1 uM of sodium arsenite for 26 days followed by removal of sodium arsenite for 10 days, measured at day 36 (iAs-Rev); and chronic arsenic exposure of 1 uM of sodium arsenite for 26 days, followed by removal of sodium arsenite exposure for 10 days, followed by 1 uM of chronic sodium arsenite exposure for 10 days (measured at day 46) (iAs-Rev-T).

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