9195

8497

كارشناسي ارشد

بيوتكنولوژي كشاورزي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1393

شانزده،105ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

آذرشاه پيري

محمدعلي اسلامي

27/7/93

مجيد طالبي، آقافخرميرلوحي

مهندسي كشاورزي

ID8497

018 Transfer of Gene Encoding one of Rice Metallothionein Isoforms OsMTI 1b in to Saccharomyces cerevisiae for Enhancement of Resistance to Oxidative stress Zahra ansary pour Za2569@yahoo com June20 2014 Department of Agricultural Biotechonolgy Isfahan University of Technology Isfahan IranDegree M Sc Language Farsi1 A Shahpiri a shahpiri@cc iut ac ir2 M A asadollahi masadollahi@yahoo comAbstractSaccharomyces cerevisiae is the most important industrial yeast and the main microorganism employed inbioethanol production Industrial yeast strains during fermentation are exposed to various stresses such asosmotic shock oxidative stress and toxicity of secondary metabolites which lead to the loss of biologicalproducts At relatively low concentrations ethanol inhibits cell division decreases cell volume and specificgrowth rate while high ethanol concentrations reduce cell vitality and increase cell death Thereforesuccessful fermentation requires yeast strains resistant to high concentrations of ethanol Studies have shownincreased expression of a number of genes involved in the detoxification of reactive oxygen species ROS including thioredoxin catalase and glutathione reductase in response to an oxidant challenge This increasedsynthesis of antioxidants forms the basis of the adaptive response in which treatment with low amounts ofoxidant induces resistance to subsequent and otherwise lethal doses In this study the rice metallothioneinencoding gene isoform OsMTI 1b in the yeast S cerevisiae in order to enhance resistance against H2O2 Thisgene was first cloned in GPD shuttle expression vector and then transferred to S cerevisiae However theengineered strain showed little resistance to oxidative stress To enhance expression solubility and stability ofOsMTI 1b in yeast cells the sequence encoding glutathione S transferase GST was placed at the beginningof OsMTI 1b Then the GPD GST OsMTI 1b construct was transferred to yeast cells After confirming theGST OsMTI 1b protein expression by Western blot the culture media were supplemented with differentconcentrations of H2O2 cadmium and ethanol The results revealed better growth and higher final biomassconcentrations of yeast cells expressing OsMTI 1b fused with GST as compared to the control strain thestrain expressing only empty plasmid in the presence of 0 9 mM cadmium 10 ethanol and 3 mM H2O2 Determination of cadmium concentration in the culture medium at T0 immediately after the addition ofcadmium to the medium and T1 five hours after the addition of cadmium showed lower cadmiumconcentrations in the culture medium for the engineered strain which suggests metal accumulation in the yeastcells containing the GST OsMTI 1b and the cadmium binding ability of this protein Keyword Saccharomyces cerevisiae Rice Metallothionein Cloning Oxidative Stress Ethanol Cadmium

آذرشاه پيري

محمدعلي اسلامي

مجيد طالبي، آقافخرميرلوحي