Accumulation of O2-tolerant phenotypes in H2-producing strains of Chlamydomonas reinhardtii by sequential applications of chemical mutagenesis and selection
Accumulation of O2-tolerant phenotypes in H2-producing strains of Chlamydomonas reinhardtii by sequential applications of chemical mutagenesis and selection
复制标题
DOI：
10.1016/s0360-3199(02)00117-9
复制
发表时间：
2002-11-01
影响因子：
7.2
通讯作者：
Seibert, M
中科院分区：
文献类型：
--
作者：
Flynn, T;Ghirardi, ML;Seibert, M
厌氧诱导的藻类光生氢是由一种双向氢化酶催化的，该酶可被氧气迅速灭活。我们分离出两代莱茵衣藻菌株，其H-2进化活性高达野生型（WT）中所见O-2耐受性的10倍。这些菌株产生的两个连续的选择，包括随机化学诱变，富集H-2代谢克隆后，暴露于增加量的O-2，和筛选使用的化学显色传感器。通过两种类型的测定对所选菌株进行表征，并将其分类为（a）暴露于使WT菌株失活的O-2浓度后可产生H-2的菌株和（B）另外，一旦去除O-2，能够快速重新激活H-2产生活性的菌株。这些结果表明，O-2-耐受性可以通过连续几轮的诱变、选择和筛选来增加，表明WT表型可以通过遗传手段来改善。其他结果表明，氢化酶是不敏感的O-2时，它是积极催化H-2的演变。由Elsevier Science Ltd代表国际氢能协会发布。
The photoproduction of hydrogen by anaerobically induced algae is catalyzed by a bidirectional hydrogenase that is rapidly inactivated by oxygen. We isolated two generations of Chlamydomonas reinhardtii strains with H-2-evolving activities of up to 10 times the O-2-tolerance seen in the wild-type (WT). These isolates were generated by two sequential selections, consisting of random chemical mutagenesis, enrichment for H-2-metabolism clones following exposure to increasing amounts of O-2, and screening using a chemochromic sensor. The selected strains were characterized by two types of assays and classified as those that (a) can evolve H-2 following exposure to O-2 Concentrations that inactive the WT strain and (b) in addition, are able to quickly reactivate H-2-production activity once O-2 is removed. These results suggest that O-2-tolerance can be increased by successive rounds of mutagenesis, selection, and screening, demonstrating that the WT phenotype can be improved by genetic means. Other results show that the hydrogenase is less sensitive to O-2 when it is actively catalyzing H-2 evolution. Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.