Cheng Yuan-Yuan, Wang Wen-Jing, Ding Shi-Ting, Zhang Ming-Xing, Tang Ai-Guo, Zhang Ling, Li Dao-Bo, Li Bing-Bing, Deng Guo-Zhi, Wu Chao
School of Life Sciences, Anhui University, China.
Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, China.
Appl Environ Microbiol. 2021 Apr 15;87(8). doi: 10.1128/AEM.02716-20. Epub 2021 Jan 29.
is a model strain of the electrochemical active bacteria (EAB) because of its strong capability of extracellular electron transfer (EET) and genetic tractability. In this study, we investigated the effect of carbon sources on EET in by using reduction of palladium ions (Pd(II)) as a model and found that pyruvate greatly accelerated the Pd(II) reduction compared with lactate by resting cells. Both Mtr pathway and hydrogenases played a role in Pd(II) reduction when pyruvate was used as a carbon source. Furthermore, in comparison with lactate-feeding , the transcriptional levels of formate dehydrogenases involving in pyruvate catabolism, Mtr pathway, and hydrogenases in pyruvatefeeding were up-regulated. Mechanistically, the enhancement of electron generation from pyruvate catabolism and electron transfer to Pd(II) explains the pyruvate effect on Pd(II) reduction. Interestingly, a 2-h time window is required for pyruvate to regulate transcription of these genes and profoundly improve Pd(II) reduction capability, suggesting a hierarchical regulation for pyruvate sensing and response in The unique respiration of EET is crucial for the biogeochemical cycling of metal elements and diverse applications of EAB. Although a carbon source is a determinant factor of bacterial metabolism, the research into the regulation of carbon source on EET is rare. In this work, we reported the pyruvate-specific regulation and improvement of EET in and revealed the underlying mechanism, which suggests potential targets to engineer and improve the EET efficiency of this bacterium. This study sheds light on the regulatory role of carbon sources in anaerobic respiration in EAB, providing a way to regulate EET for diverse applications from a novel perspective.
因其强大的胞外电子转移（EET）能力和遗传易处理性，是电化学活性细菌（EAB）的模式菌株。在本研究中，我们以钯离子（Pd(II)）的还原为模型，研究了碳源对EET的影响，发现丙酮酸比乳酸能更显著地加速静息细胞对Pd(II)的还原。当丙酮酸用作碳源时，Mtr途径和氢化酶在Pd(II)还原中均发挥作用。此外，与以乳酸为底物的情况相比，丙酮酸代谢、Mtr途径和氢化酶相关的甲酸脱氢酶在以丙酮酸为底物时的转录水平上调。从机制上讲，丙酮酸分解代谢产生电子以及电子向Pd(II)转移的增强解释了丙酮酸对Pd(II)还原的影响。有趣的是，丙酮酸调节这些基因的转录并显著提高Pd(II)还原能力需要2小时的时间窗口，这表明在中对丙酮酸感应和反应存在分级调节。EET独特的呼吸作用对于金属元素的生物地球化学循环和EAB的多种应用至关重要。尽管碳源是细菌代谢的决定性因素，但关于碳源对EET调节的研究却很少。在这项工作中，我们报道了丙酮酸对EET的特异性调节和改善，并揭示了潜在机制，这为改造和提高该细菌的EET效率提供了潜在靶点。本研究揭示了碳源在EAB厌氧呼吸中的调节作用，从新的角度为多种应用调节EET提供了一种方法。
