Min Kyung-Jin, Tatar Marc
Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence, RI 02912, USA.
Mech Ageing Dev. 2006 Jul;127(7):643-6. doi: 10.1016/j.mad.2006.02.005. Epub 2006 Apr 17.
Dietary restriction extends adult Drosophila melanogaster life span when the concentration of dietary yeast is diluted in a media with abundant carbohydrates. Here we vary the concentration of casein as a source of amino acids in adult diet to uncover a quality of nutrient yeast responsible for longevity control. Longevity is maximized upon diet with intermediary levels of casein. Differences in survival are not caused by elevated age-independent mortality; the longevity maximum at intermediate casein does not arise because casein is non-specifically harmful at higher concentrations. Furthermore, fecundity increases when the level of dietary casein is elevated. The demographic phenotypes of adult Drosophila maintained on intermediate levels of casein resemble their response to limited dietary yeast. Dietary restriction through dilution of yeast may extend longevity because this limits the intake of amino acids.
当在富含碳水化合物的培养基中稀释膳食酵母的浓度时，饮食限制可延长成年黑腹果蝇的寿命。在这里，我们改变成年果蝇饮食中作为氨基酸来源的酪蛋白浓度，以揭示负责寿命控制的营养酵母的一种特性。当酪蛋白水平处于中等水平时，寿命最长。生存差异并非由与年龄无关的死亡率升高引起；中等酪蛋白水平时的最长寿命并非因为酪蛋白在较高浓度下具有非特异性危害。此外，当膳食酪蛋白水平升高时，繁殖力会增加。维持在中等酪蛋白水平的成年果蝇的人口统计学表型类似于它们对有限膳食酵母的反应。通过稀释酵母进行饮食限制可能会延长寿命，因为这限制了氨基酸的摄入量。
