细菌与古菌之间的直接电子传递

Direct electron transfer between bacteria and archaea

摘要:

微生物种间直接电子传递是指在厌氧条件下，一种微生物将电子直接传递给另外一种微生物，将两种不同微生物的代谢途径耦合在一起，以达到互养共生的目的。细菌-古菌之间的直接电子传递是其物质转换与能量代谢的新途径和新调控机制，直接参与甲烷的合成以及与硫酸盐还原耦合的厌氧甲烷氧化，在驱动碳和硫的地球化学转化与循环中起着十分重要的作用。目前研究结果认为细菌-古菌之间的直接电子传递主要是由含多个血红素的C型细胞色素介导的，这些细胞色素能形成不间断的胞外电子传递途径，以电子多步跃迁机制在细菌和古菌的细胞质膜之间传递电子。

关键词:细菌;古菌;种间直接电子传递;多个血红素的C型细胞色素

Abstract:

Under anoxic condition, a microorganism can transfer electrons directly to another microorganism (i.e., direct interspecies electron transfer or DIET) to couple the metabolic capability of the two microorganisms for their syntrophic growth. DIET between bacteria and archaea is the new way for energy exchange between bacteria and archaea as well as the new mechanisms for regulating their metabolisms. Furthermore, DIET between bacteria and archaea is directly involved in methane formation and the anoxic methane oxidation coupled to sulfate reduction. Thus, DIET between bacteria and archaea plays a crucial role in global biogeochemical transformation and cycling of carbon and sulfur. Finally, all currently available data suggest that multi-heme c-type cytochromes may form continuously extracellular electron transfer pathways to mediate electron transfer between the cytoplasmic membranes of bacteria and archaea via the multi-step hopping mechanism.

Key words:bacteria;archaea;direct interspecies electron transfer;multi-heme c-type cytochromes