Antioxidants and Regulation of Antioxidant Enzymes by Cellular Redox Status

It has been well known that free radicals have numerous detrimental effects in both in vitro and in vivo in biological systems because of their unavoidable and tremendous reactivity against biological macromolecules especially proteins, carbohydrates and nucleic acids. They are produced in the biological systems continuously by various mechanisms and eliminated by cellular antioxidant systems. If not eliminated sufficiently, or there is a disturbance in their neutralization, inevitable cellular damage may occur. Activities or the presence of antioxidant enzymes in the cells are under strong regulation with transcriptional, translational and post translational mechanisms as a consequence of changes in cellular redox potential. Redox sensitive metabolic enzymes or proteins; such as protein phosphatases, NF-?B and AP-1, are capable of sensing the oxidant signals by reversible oxidation of their regulatory units which cause them to transduce the signal and adjust the cellular antioxidant metabolism. Redox sensitive proteins execute their functions via kinases, phosphatases, and transcription factors influencing the steady state levels of antioxidant enzymes. Therefore, cells may sense, transduce, and translate the oxidant signals into appropriate cellular responses depending on the cellular redox state. This rewiev focused on the basic definitions for the free radicals and the tissue defense mechanism and the possible regulation mechanisms of antioxidant enzymes in the situations undergoing reversible changes in cellular redox status

The Impact of Employment Web Sites' Traffic on Unemployment: A Cross Country Comparison

Although employment web sites have recently become the main source for re- cruitment and selection process, the relation between those sites and unemploy- ment rates is seldom addressed. Deriving data from 32 countries and 427 web sites, this study explores the correlation between unemployment rates of European countries and the attractiveness of country specific employment web sites. It also compares the changes in unemployment rates and traffic on all the aforementioned web sites. The results showed that there is a strong correlation between web sites traffic and unemployment rates.Comment: 9 page

Reciprocal Modulation of Hepatic Cytochrome P450 Gene Expressions with Streptozotocin Induced Diabetes and Resveratrol

Cytochrome P450s are very large and diverse superfamily of hemoproteins found in all domains of life and diverse array of compounds can influence the relative concentrations and/or activities of P450s. Expression of P450s is modulated not only by exposure to various chemicals, but also by some pathophysiological conditions such as diabetes, hypertension and obesity. Six different Cytochrome P450 isoforms namely; 1A1, 2A1, 2E1, 2C11, 3A1, 4A1 were quantified by quantitative Real Time PCR to assess the relative expressions of CYPs mRNA in control and diabetic rat liver tissues. At the same time, effects of resveratrol (RSV) on these isoforms were evaluated. According to results, diabetes enhanced the CYP1A1, CYP2E1 and CYP3A1 gene expression and RSV reduced to these increments toward the control values. Furthermore, while CYP2C11 and CYP4A1 expressions were found to be reduced by diabetes, application of RSV decreased these isoforms’expressions further. Additionally, diabetes and RSV treatment did not alter the CYP2A1&2 expressions significantly. As a result, expressions of cytochrome P450 were altered not only by diabetes but also by exposure to antioxidants such as resveratrol and levels of expressions of each isoforms are important factors determining the biological consequences of xenobiotics and antioxidant defense systems in diabetes

Microbial evolution in the chemostat

Imperial Users onl