A difference in the proteins found in young adults of inbred strains of Drosophila melanogaster which correlates with genetically-determined, long or short life span

Purification and characterization of a protein associated with genetically-determined longevity difference in Drosophila melanogaster

Earlier studies have shown a correlation between the presence of a 77 kDa protein in the proteins extracted from young adult Drosophila melanogaster (D.m.) and the autosomal longevity allele. A2 at the JmA locus. In this study, a 77 kDa protein has been isolated from pupae of D.m. of a long-lived strain of genotype A2A2, and was purified by DEAE chromatography, ConA column chromatography, and two cycles of gel filtration. The purified protein has a molecular weight of 76,600 (by SDS-PAGE), an isoelectric point of pH 6.5, and molar extinction coefficient A(280(1%) = 18.3. It is a glycoprotein containing 3.3% hexose. Supplementing the food of D.m. with the purified protein at 5 x 10(-4) micrograms/ml, beginning at day 5 after emergence, resulted in an increase in the survival rate and maximal life span of both short-lived and long-lived strains of D.m.

Geroprotector efficiency depends on viability of control population: life span investigation in D. melanogaster

Ability of the radical spin trap 4-hydroxy-2,2,6,6,-tetramethyl-l-piperidine-N-oxyl (4-hydroxy-TemPO, (4HT)), to delay senescence in D. melanogaster has been studied. The spin trap, at a concentration of 0.2%, was added to the culture medium at the flies development stage. Reliable correlation (r = 0.76, P < 0.05) has been found between the viability of a control population, assessed by the mean life span (LS) value, and the level of LS alteration after geroprotector treatment in a corresponding experimental population. Thereby the local minimum values and local decreases in the mean LS in successive generations of the control line are associated most likely with LS extension effects in the corresponding experimental groups after 4HT treatment, and on the contrary, the local maximum values and local increases in the mean LS of the control line are associated more probably either with LS decreasing effects in the corresponding experimental groups or with the lack of significant differences between the control and experimental groups. A possible mechanism of the discovered phenomenon is discussed, based on the concept about free-radical activity variations. A probability approach to the evaluation of geroprotector efficiency in serial studies is proposed.

Molecular biological approaches to aging in Japan: an overview

Progress in molecular biological investigations of aging in Japan is overviewed. Emphasis is put on studies which, in the author's opinion, appear to have considerable relevance to a definition of aging, i.e. functional decline of cells and tissues with advancing age. (1) Changes in the nuclear DNA, most significantly in methylation, and deletions of mitochondrial DNA have been shown to occur with age. (2) Various aspects of protein metabolism have been investigated, i.e. the fidelity of translation, accumulation of altered enzymes, oxidative damage, and half-lives and degradation of proteins. (3) Japanese researchers have made significant contributions to the understanding of the chemical structure and the mechanisms of generation of paired helical filaments in Alzheimer's disease. Also, studies on beta-amyloid peptide are noteworthy. (4) Murine models of aging were developed and molecular biological investigations on them are progressing. Nematodes and fruit flies are also used as models.(5) Changes in gene expression with age have attracted considerable interest.