Study of physiological functions of D-amino acid degradative enzymes: role of D-amino acids in reproduction and neurotransmission

秀丽隐杆线虫是一种模式生物，它有四个基因编码氧化降解d -氨基酸的酶。其中一个编码d -氨基酸氧化酶，可以降解中性和碱性d -氨基酸，而另外三个是d -天冬氨酸氧化酶，可以降解酸性d -氨基酸。在每个基因有缺陷的突变体中，观察到一些表型变化，如幼鸟数量减少，以及体内d -氨基酸含量增加。本研究对突变株的生殖细胞质量和神经传递进行了研究，并与野生型进行了比较。此外，通过DNA芯片分析鉴定了突变体中表达改变的几个基因，随后测定了鉴定基因所涉及的代谢途径中代谢物的含量，并与野生型进行了比较。在此基础上，讨论了d -氨基酸及其降解酶的生理作用。

Caenorhabditis elegans, a model organism has four genes that encode the enzymes degrading D-amino acids oxidatively. One of them encodes D-amino acid oxidase, which degrades neutral and basic D-amino acids, while the other three are D-aspartate oxidases, which degrade acidic D-amino acids. In the mutants defective in each gene, several phenotypic changes are observed such as decreased brood size, along with an increase in D-amino acid contents in the body. In this work, the quality of germ cells and the neurotransmission in the mutants were investigated and compared with those in the wild-type strain. In addition, several genes those expressions are altered in the mutants were identified by DNA microarray analysis, and subsequently the contents of metabolites in the metabolic pathway involved in the identified genes were determined and compared with those of the wild-type. Based on these results, the physiological roles of D-amino acids and their degradative enzymes were discussed.