Biomedical subjects

Pankaj Kapahi

Publications and source records attributed to Pankaj Kapahi.

5 recordsLinked to original sources

PubMed2006

Allocrine modulation of feeding behavior by the Sex Peptide of Drosophila.

Mating elicits a dramatic reprogramming of female behavior in numerous insect species. In Drosophila, this postmating response (PMR) comprises increased egg-laying rate and reduced sexual receptivity and is controlled by the products of the male accessory glands, a family of approximately 80 small peptides transferred in the male seminal fluid . Here, we show that copulation strongly stimulates female food intake. Remarkably, this change is abolished if the males lack a single, small seminal protein, the Sex Peptide (SP). Ectopic expression of SP in virgin females mimics the effect of mating on feeding behavior, demonstrating that SP is the main agent controlling this behavioral paradigm. Our observations identify enhanced feeding behavior as a novel component of the Drosophila PMR and suggest that SP represents a molecular link between energy acquisition and reproductive investment.

Animals↗

PubMed2005

Compensatory ingestion upon dietary restriction in Drosophila melanogaster.

Dietary restriction extends the lifespan of numerous, evolutionarily diverse species. In D. melanogaster, a prominent model for research on the interaction between nutrition and longevity, dietary restriction is typically based on medium dilution, with possible compensatory ingestion commonly being neglected. Possible problems with this approach are revealed by using a method for direct monitoring of D. melanogaster feeding behavior. This demonstrates that dietary restriction elicits robust compensatory changes in food consumption. As a result, the effect of medium dilution is overestimated and, in certain cases, even fully compensated for. Our results strongly indicate that feeding behavior and nutritional composition act concertedly to determine fly lifespan. Feeding behavior thus emerges as a central element in D. melanogaster aging.

Aging↗

PubMed2004

TOR pathway: linking nutrient sensing to life span.

Recent studies point to an emerging role for the TOR (target of rapamycin) pathway in the regulation of life span. In this Perspective, we discuss the possibility that this pathway is an important modulator of nutrient-dependent changes in life span. Additionally, we discuss the interactions between the TOR and insulin-like signaling pathways as well as the key downstream processes that TOR regulates.

Animals↗

PubMed2004

Regulation of lifespan in Drosophila by modulation of genes in the TOR signaling pathway.

In many species, reducing nutrient intake without causing malnutrition extends lifespan. Like DR (dietary restriction), modulation of genes in the insulin-signaling pathway, known to alter nutrient sensing, has been shown to extend lifespan in various species. In Drosophila, the target of rapamycin (TOR) and the insulin pathways have emerged as major regulators of growth and size. Hence we examined the role of TOR pathway genes in regulating lifespan by using Drosophila. We show that inhibition of TOR signaling pathway by alteration of the expression of genes in this nutrient-sensing pathway, which is conserved from yeast to human, extends lifespan in a manner that may overlap with known effects of dietary restriction on longevity. In Drosophila, TSC1 and TSC2 (tuberous sclerosis complex genes 1 and 2) act together to inhibit TOR (target of rapamycin), which mediates a signaling pathway that couples amino acid availability to S6 kinase, translation initiation, and growth. We find that overexpression of dTsc1, dTsc2, or dominant-negative forms of dTOR or dS6K all cause lifespan extension. Modulation of expression in the fat is sufficient for the lifespan-extension effects. The lifespan extensions are dependent on nutritional condition, suggesting a possible link between the TOR pathway and dietary restriction.

Adipose Tissue↗

PubMed2002

Spatio-temporal analysis of gene expression during aging in Drosophila melanogaster.

The relationship between gene expression and the regulation of longevity is poorly understood. Previous studies focusing on microarray or tissue-specific changes in gene expression as a function of age have provided evidence that gene expression is a dynamic process which is regulated, even late in an organism's lifespan. Using the enhancer-trap technique, a systematic analysis of the spatio-temporal regulation of gene expression in tissues of adult Drosophila is presented. As many as 80% of enhancer traps analysed displayed (some form of) transcriptional change with age. In some cases the rate of change in expression was found to correlate with changes in longevity under various conditions, suggesting that they may be indicators of 'physiological age' and therefore valuable markers for dissecting the aging process. Molecular analysis of enhancer traps that showed increased activity with age was performed to identify candidate genes that may be important in the regulation of longevity; we identified changes in reporters associated with immunity, microtubule organization and muscle function.

Aging↗