Stephen L. Helfand

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Caloric restriction extends lifespan in numerous species. In the budding yeast Saccharomyces cerevisiae this effect requires Sir2 (ref. 1), a member of the sirtuin family of NAD+-dependent deacetylases. Sirtuin activating compounds (STACs) can promote the survival of human cells and extend the replicative lifespan of yeast. Here we show that resveratrol and(More)
Calorie restriction can extend life span in a variety of species including mammals, flies, nematodes, and yeast. Despite the importance of this nearly universal effect, little is understood about the molecular mechanisms that mediate the life-span-extending effect of calorie restriction in metazoans. Sir2 is known to be involved in life span determination(More)
Ultrabithorax (Ubx) is a Drosophila homeotic gene that determines the segmental identities of parts of the thorax and abdomen. Appropriate Ubx transcription requires a long upstream control region (UCR) that is defined genetically by the bithoraxoid (bxd) and postbithorax (pbx) subfunction mutations. We have directly analyzed UCR functions by the(More)
Aging is genetically determined and environmentally modulated. In a study of longevity in the adult fruit fly, Drosophila melanogaster, we found that five independent P-element insertional mutations in a single gene resulted in a near doubling of the average adult life-span without a decline in fertility or physical activity. Sequence analysis revealed that(More)
Dietary restriction (DR) is a valuable experimental tool for studying the aging process. Primary advancement of research in this area has relied on rodent models, but attention has recently turned toward Drosophila melanogaster. However, little is known about the baseline effects of DR on wild-type Drosophila and continued experimentation requires such(More)
The Ubx and bxd transcription units comprise a single functional domain in the bithorax complex of Drosophila melanogaster. The segmental distributions and nuclear localization of proteins encoded by the Ubx unit have been determined by immunofluorescence staining with antibodies raised against a fusion protein containing Ubx coding sequences. Wild-type and(More)
Insect embryos, with their relatively simple nervous systems, provide a model system with which to study the cellular and molecular mechanisms underlying cell recognition during neuronal development. Such an approach can take advantage of the accessible cells of the grasshopper embryo and the accessible genes of Drosophila. The growth cones of identified(More)
Although the Drosophila visual system has been described extensively, little is known about its olfactory system. A major reason for this discrepancy has been the lack of simple, reliable means of measuring response to airborne chemicals. This paper describes a jump response elicited by exposing Drosophila to chemical vapors. This behavior provides the(More)
Hyperactivation of p53 leads to a reduction in tumor formation and an unexpected shortening of life span in two different model systems . The decreased life span occurs with signs of accelerated aging, such as osteoporosis, reduction in body weight, atrophy of organs, decreased stress resistance, and depletion of hematopoietic stem cells. These observations(More)
The oxidative stress hypothesis of aging predicts that a reduction in the generation of mitochondrial reactive oxygen species (ROS) will decrease oxidative damage and extend life span. Increasing mitochondrial proton leak-dependent state 4 respiration by increasing mitochondrial uncoupling is an intervention postulated to decrease mitochondrial ROS(More)