Masuda Sachiko, Hennecke Hauke, Fischer Hans-Martin
RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.
ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland.
Genes (Basel). 2017 Dec 15;8(12):390. doi: 10.3390/genes8120390.
One of the many disparate lifestyles of is chemolithotrophic growth with thiosulfate as an electron donor for respiration. The employed carbon source may be CO₂ (autotrophy) or an organic compound such as succinate (mixotrophy). Here, we discovered three new facets of this capacity: (i) When thiosulfate and succinate were consumed concomitantly in conditions of mixotrophy, even a high molar excess of succinate did not exert efficient catabolite repression over the use of thiosulfate. (ii) Using appropriate cytochrome mutants, we found that electrons derived from thiosulfate during chemolithoautotrophic growth are preferentially channeled via cytochrome to the ₃-type heme-copper cytochrome oxidase. (iii) Three genetic regulators were identified to act at least partially in the expression control of genes for chemolithoautotrophic thiosulfate oxidation: RegR and CbbR as activators, and SoxR as a repressor.
其众多不同生活方式之一是以硫代硫酸盐作为呼吸作用的电子供体进行化能无机营养生长。所利用的碳源可以是CO₂（自养）或有机化合物，如琥珀酸盐（兼养）。在此，我们发现了这种能力的三个新方面：（i）在兼养条件下硫代硫酸盐和琥珀酸盐同时被消耗时，即使琥珀酸盐的摩尔过量很高，也不会对硫代硫酸盐的利用产生有效的分解代谢物阻遏作用。（ii）使用合适的细胞色素突变体，我们发现化能无机自养生长过程中来自硫代硫酸盐的电子优先通过细胞色素传递到Ⅲ型血红素-铜细胞色素氧化酶。（iii）鉴定出三种遗传调节因子至少部分作用于化能无机自养硫代硫酸盐氧化基因的表达控制：RegR和CbbR作为激活剂，SoxR作为阻遏剂。
