Biochemical changes associated with the mechanism controlling superoxide radical formation in the aging rotifer.

Levels of the superoxide radical (SOR) and lipid peroxides were measured and found to increase during aging in the short-lived rotifer, Asplanchna brightwelli. Life-span was altered by changes in environmental temperature, absence of light, diet restriction, exposure to ultraviolet radiation, and addition of vitamin E to the diet. Each of the conditions that lengthened life-span decreased SOR and lipid peroxide levels, and each condition that shortened life-span increased levels of SOR and lipid peroxides. Additional experiments indicated that on the third day of age, there was a significant increase in Ca2+ uptake and phospholipase A2 activity in membrane samples and an elevation in superoxide dismutase and catalase activity in rotifer homogenates. In addition, SOR concentration was inhibited by the addition of bromophenacyl bromide and indomethacin to membrane samples. By day 5 there was also a significant increase in the lysosomal enzyme, alpha-mannosidase. The results of this study indicate that levels of the SOR and lipid peroxides are coupled to rotifer life-span and that activation of phospholipase A2 may contribute to the elevation of these agents in older animals.