Kurchii, B.A. .
Oxidants and antioxidants are simultaneously formed during oxidative breakdown of biological membranes.
Biological membranes are composed from many chemicals that under normal physiological condition are mostly neutral. The very important factor is that membranes possess in the own antioxidative systems composed as from lipids as from non-lipidic substances. During oxidative breakdown of membranes are formed many classes of antioxidative chemicals. Among them the following classes of antioxidants take part in the antioxidative defense reactions: (1) PROSTAGLANDINS (for example, PGD2, PGE2 , PGF2a); (2) STEROLS (for example, cholesterol, testosterone, pregnenolone, 31-norlanosterol, ergosterol, cholesterol, campestanol, sitosterol, stigmasterol, lanosterol, etc.); (3) CAROTENOIDS. Oxidative breakdown of membranes also accompanies by the formation of substances termed as putative signalling molecules. Nevertheless, many of these substances are in reality final stable products from oxidative breakdown of the membraneous compounds. For example, jasmonic acid is formed as a final product during oxidative breakdown of linolenic acid. Other chemicals that are formed during activation of oxidative processes in the cells are ethylene (is formed from choline) and nitric oxide. Many works proposed that these chemicals initiate transcription processes to activate defense reactions. I believe that this is NONSENSE because all these chemicals are constantly present in the law concentration in the cell under normal physiological conditions. These chemicals can only suggest that in the cell occurred non-controlled by antioxidative systems processes. Nevertheless under several condition they can also act as oxidants. The quantity of only natural biologically active substances exceeds the quantity of genes in the cell. Moreover, the quantity of synthetic substances is more than one hundred thousands. I proposed (Kurchii, 1998; 2004) that signalling molecules are special DNA-protein complexes (gene keys) in the cellular compartments that are liberated during oxidative damaging of the cell and initiate transcription after conjugation with gene locks. This is the first reaction of the vital cells to the oxidative stress.
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1 - Institute of Plant Physiology and Genetics, 31/17 Vasylkivska St.,, Kiev, 03022, Ukraine
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM