Age-dependent alpha-glycerophosphate dehydrogenase activity changes in mutant and wild type Drosophila melanogaster

Functional senescence in Drosophila melanogaster

The fruit fly Drosophila melanogaster is one of the principal model organisms used for studying the biology of aging. Flies are well suited for such studies for a number of reasons. Flies develop to adulthood quickly, have a relatively short life span, and are inexpensive to house. Most of the fly genome has been sequenced, powerful genetic tools are available to manipulate it, and most fly genes have obvious homologues in mammals. While the majority of aging studies in flies have focused on regulation of life span, the fly is emerging as a powerful model system for investigating the biology that underlies age-related functional decline. Key to the use of flies in this way is the striking number of parallels between functional senescence in Drosophila and humans. Here, we review age-related functional declines in Drosophila, human correlates of these age-related declines, and common mechanisms that influence longevity and specific aspects of functional senescence in flies.

Biomarkers of aging

This article presents a conceptual discussion of some aspects involved in biomarkers of aging. A biomarker of aging is a biological parameter of an organism that either alone or in some multivariate composite will, in the absence of disease, better predict functional capability at some late age than will chronological age. The reasons for undertaking biomarker research, criteria for putative biomarkers, measurement and assessment of putative biomarkers, and the new initiative by the National Institute on Aging in biomarker research are discussed.

Influence of age on mitochondrial enzyme levels in Drosophila

The specific activity and the activity per fly of four mitochondrial enzymes did not change with ageing in male Drosophila melanogaster (Oregon R). The enzymes assayed were rotenone-insensitive NADH-cytochrome c reductase, adenylate kinase, succinate cytochrome c reductase, and malate dehydrogenase, located in the outer membrane, inner membrane space, inner membrane and matrix, respectively. The specific activity of malate dehydrogenase showed no significant change for young and old head, thorax and abdomen. We conclude that there is no specific site for ageing damage in the mitochondrion, when the enzyme activities in this study are used as an indicator. It should be noted, however, that these enzymes represent only a small percentage of the total enzymes present in mitochondria.

Developmental time and adult longevity in two strains of Drosophila melanogaster in a constant low-stress environment

This study examines the life spans of wild type flies (Sevelen strain, n = 2991) and post-replication DNA repair-deficient flies (mei-41D5, n = 1607) as members of age-synchronized birth cohorts and as members of full sibships. Flies were individually housed from the time they were laid as eggs until they died as imagoes; environmental conditions were constant throughout the life span of these virgins. In this minimal stress experiment, developmental time and imaginal longevity were negligibly correlated (r = -0.09 to -0.25), even though developmental time was canalized at different levels in both strains. Previous research involving environmental perturbations during the life span of Drosophila (e.g. temperature, diet, population density) has demonstrated significant strong correlations, mostly positive, between developmental time and adult longevity. We have demonstrated that the duration of development and aging are not coupled in the absence of such stresses. We therefore suggest that related changes in the duration of the pre-imaginal and the adult stages of the lifecycle of Drosophila may have evolved through adaptation to environmental stresses.