期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：2
页码：610-614
DOI：10.1073/pnas.74.2.610
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Metronidazole (2-methyl-5-nitroimidazole-l-ethanol) is shown to be effective for the selective enrichment of mutants of Chlamydomonas reinhardtii that posses impaired photosynthetic electron transport. More than 99.9% of wild-type cells are killed when incubated in the presence of 6-10 mM metronidazole for 24 hr under illumination of 7500 lux. Survival of wild-type cells in darkness and of mutants that are blocked at different steps in photosynthetic electron transport is nearly 100% when incubated in the presence of the drug under identical conditions. The toxicity of metronidazole is demonstrated to depend upon its reduction by photosynthetic electron transport. Light-dependent oxygen uptake mediated by metronidazole is shown to require active photosystem l in vitro and in vivo. Ferredoxin is necessary for metronidazole reduction by thylakoid membrane fractions enriched in photosystem l activity. We propose that the toxicity of metronidazole is due to the formation of lethal derivatives of the drug or to the accumulation of hydrogen peroxide, which could occur upon autooxidation of metronidazole reduced by one electron. The results indicate that mutants of C. reinhardtii, and probably other photosynthetic organisms, with any lesion in photosynthetic electron transport from the oxidizing side of photosystem ll to ferredoxin can be isolated by metronidazole treatment of mutagenized cultures.
