Saiki Ryoichi, Lunceford Adam L, Bixler Tarra, Dang Peter, Lee Wendy, Furukawa Satoru, Larsen Pamela L, Clarke Catherine F
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Aging Cell. 2008 Jun;7(3):291-304. doi: 10.1111/j.1474-9726.2008.00378.x. Epub 2008 Feb 11.
Coenzyme Q(n) is a fully substituted benzoquinone containing a polyisoprene tail of distinct numbers (n) of isoprene groups. Caenorhabditis elegans fed Escherichia coli devoid of Q(8) have a significant lifespan extension when compared to C. elegans fed a standard 'Q-replete'E. coli diet. Here we examine possible mechanisms for the lifespan extension caused by the Q-less E. coli diet. A bioassay for Q uptake shows that a water-soluble formulation of Q(10) is effectively taken up by both clk-1 mutant and wild-type nematodes, but does not reverse lifespan extension mediated by the Q-less E. coli diet, indicating that lifespan extension is not due to the absence of dietary Q per se. The enhanced longevity mediated by the Q-less E. coli diet cannot be attributed to dietary restriction, different Qn isoforms, reduced pathogenesis or slowed growth of the Q-less E. coli, and in fact requires E. coli viability. Q-less E. coli have defects in respiratory metabolism. C. elegans fed Q-replete E. coli mutants with similarly impaired respiratory metabolism due to defects in complex V also show a pronounced lifespan extension, although not as dramatic as those fed the respiratory deficient Q-less E. coli diet. The data suggest that feeding respiratory incompetent E. coli, whether Q-less or Q-replete, produces a robust life extension in wild-type C. elegans. We believe that the fermentation-based metabolism of the E. coli diet is an important parameter of C. elegans longevity.
辅酶Q(n)是一种完全取代的苯醌，含有不同数量(n)异戊二烯基团的聚异戊二烯尾巴。与喂食标准“富含Q”大肠杆菌饮食的秀丽隐杆线虫相比，喂食不含Q(8)的大肠杆菌的秀丽隐杆线虫寿命显著延长。在这里，我们研究了由不含Q的大肠杆菌饮食导致寿命延长的可能机制。一项Q摄取生物测定表明，Q(10)的水溶性制剂能被clk-1突变体和野生型线虫有效摄取，但不能逆转由不含Q的大肠杆菌饮食介导的寿命延长，这表明寿命延长并非由于饮食中缺乏Q本身。由不含Q的大肠杆菌饮食介导的寿命延长不能归因于饮食限制、不同的Qn异构体、致病性降低或不含Q的大肠杆菌生长缓慢，实际上需要大肠杆菌的活力。不含Q的大肠杆菌在呼吸代谢方面存在缺陷。喂食因复合物V缺陷而具有类似呼吸代谢受损的富含Q的大肠杆菌突变体的秀丽隐杆线虫也显示出明显的寿命延长，尽管不如喂食呼吸缺陷型不含Q的大肠杆菌饮食的线虫那么显著。数据表明，喂食呼吸功能不全的大肠杆菌，无论是否不含Q，都会使野生型秀丽隐杆线虫的寿命大幅延长。我们认为，大肠杆菌饮食基于发酵的代谢是秀丽隐杆线虫寿命的一个重要参数。
