Effects of dietary folic acid level and symbiotic folate production on fitness and development in the fruit fly Drosophila melanogaster
Effects of dietary folic acid level and symbiotic folate production on fitness and development in the fruit fly Drosophila melanogaster
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DOI：
10.4161/fly.4.4.13258
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发表时间：
2010-10-01
期刊：
影响因子：
1.2
通讯作者：
Harrison, Jon F.
中科院分区：
文献类型：
--
作者：
Blatch, Sydella A.;Meyer, Kyle W.;Harrison, Jon F.
叶酸可能是一种对所有动物都适用的维生素。当转化为叶酸形式时，它被用于DNA合成和氨基酸代谢。文献表明，昆虫必须消耗叶酸，叶酸不会影响其他人，对某些人来说是一种毒素，少数昆虫会合成叶酸。据报道，果蝇并不总是需要饮食中的叶酸，因为它可以合成叶酸。这似乎不太可能，因为动物通常缺乏这种能力。更有可能的是，被认为是由苍蝇产生的叶酸来自微生物共生体。我们的目的是阐明饮食中的叶酸如何影响果蝇的健康和发育，以及果蝇是否可能从微生物共生体中获得叶酸。我们发现，随着饲料叶酸的增加，幼虫的存活和发育速度都更快，但令人惊讶的是，摄食几乎为零的叶酸的幼虫发育更快。他们体内的叶酸水平与那些摄入高达600倍的叶酸的人没有显著差异。然而，当从饮食中排除抗生素时，这些喂食少量叶酸的果蝇只能达到正常的体内叶酸水平和发育时间。当果蝇摄入含有抗生素的几乎为零的叶酸时，它们的体内叶酸水平下降，发育时间延长。用于产生实验果蝇的内共生沃尔巴克氏菌的化验没有显示这些细菌的存在。我们的数据表明，黑腹果蝇体内可能存在未知的细菌共生体(S)，这种共生体在食物中缺乏叶酸时为寄主提供必要的叶酸，使果蝇能够维持生长和发育。
Folic acid is a vitamin for probably all animals. When converted to folate forms, it is used in DNA synthesis and amino acid metabolism. Literature suggests insects must consume folates, folates do not affect others, is a toxin for some, and that a few insects synthesize it. It has been reported that Drosophila melanogaster does not consistently need dietary folate because it can synthesize it. This seems unlikely since animals generally lack this ability. More likely, folates thought to have been made by the fly came from microbial symbionts. We aimed to clarify how dietary folic acid affects fitness and development in fruit flies and whether flies may receive folates from microbial symbionts. We found larvae were more viable and developed faster with increasing dietary folic acid, with the surprising exception that larvae fed nearly-zero folic acid developed faster. Their body folate levels did not significantly differ from those that consumed up to 600 times more folic acid. However, these flies fed little folate only achieved normal body folate levels and development times when antibiotics were excluded from the diet. When flies consumed near-zero folates with antibiotics, their body folate levels decreased and development was prolonged. An assay for the endosymbiont Wolbachia in flies used to generate the experimental flies did not show presence of these bacteria. Our data suggest D. melanogaster can harbor unknown bacterial symbiont(s) that provide essential folates to their host when it is scarce in the diet, allowing the fruit fly to maintain growth and development.