Properties of ATPase activity associated with peroxisomes of rat and bovine liver.

1. Peroxisomes were isolated from bovine and rat liver by use of differential and density gradient centrifugations. 2. In the final density gradient (Nycodenz) a distinct peak of ATPase activity codistributed with the peroxisome marker catalase and was well separated from the bulk of the ATPase activity and from markers for other subcellular organelles. 3. The peroxisome-associated ATPase had a pH optimum of 7.5 and was inhibited by N-ethylmaleimide, by N,N'-dicyclohexylcarbodiimide and by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, but was unaffected by up to 30 microM n-tributyltin chloride. 4. Prolonged incubation with oligomycin at high concentrations indicated that 50% of peroxisomal ATPase was resistant to this inhibitor. The oligomycin-sensitive ATPase activity required at least a four-fold higher ratio of inhibitor to protein for inhibition than mitochondrial ATPase did. It was concluded that oligomycin-sensitive and oligomycin-resistant ATPase may be associated with liver peroxisomes.     

Social rank and sex ratio of captive long-tailed macaque females (Macaca fascicularis)

Variation in birth sex ratios in primates can be accounted for by two hypotheses: the local resource competition hypothesis [Silk: American Naturalist 121:56–66, 1983] and the hypothesis of Trivers & Willard [Science 179:90–92, 1973] concerning the maternal effect on the quality of a male. We examined the effects of female dominance rank on aspects of reproduction in three well-established captive groups of long-tailed macaques (Macaca fascicularis). High-ranking females produced a higher proportion of sons than low-ranking females, and factors other than rank did not have significant effects on birth sex ratios. Interbirth intervals following daughters were longer than those following sons, but they were independent of the mother's rank. The sons of high-ranking mothers had better survival prospects than sons of low-ranking mothers in some of the groups; no such difference was found for daughters. Overall, there was no sex difference in survival up to 5 years of age. These results support the Trivers-Willard hypothesis rather than the local resource competition hypothesis. An analysis of interbirth intervals suggested that the deviation in birth sex ratio is already established at conception.