Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
mBio. 2024 Sep 11;15(9):e0058024. doi: 10.1128/mbio.00580-24. Epub 2024 Aug 2.
To investigate their roles in extracellular electron transfer (EET), the porin-cytochrome () gene clusters , , and of the Gram-negative bacterium were deleted. Failure to delete all gene clusters at the same time suggested their essential roles in extracellular reduction of Fe(III)-citrate by . Deletion of had no impact on bacterial reduction of Fe(III)-citrate but diminished bacterial reduction of ferrihydrite and abolished anode reduction and direct interspecies electron transfer (DIET) to and . Although it had no impact on the bacterial reduction of Fe(III)-citrate, deletion of delayed ferrihydrite reduction, abolished anode reduction, and diminished DIET. Deletion of had little impact on DIET but diminished bacterial reductions of Fe(III)-citrate, ferrihydrite, and anodes. Most importantly, deletions of both and restored bacterial reduction of ferrihydrite and anodes and DIET. Enhanced expression of in this double mutant when grown in coculture with ΔΔ suggested that this cluster might compensate for impaired EET functions of deleting and . Thus, these gene clusters played essential, distinct, overlapping, and compensatory roles in EET of that are difficult to characterize as deletion of some clusters affected expression of others. The robustness of these gene clusters enabled to mediate EET to different acceptors for anaerobic growth even when two of its three gene clusters were inactivated by mutation. The results from this investigation provide new insights into the roles of gene clusters in bacterial EET.
The Gram-negative bacterium is of environmental and biotechnological significance. Crucial to the unique physiology of is its extracellular electron transfer (EET) capability. This investigation sheds new light on the robust roles of the three porin-cytochrome () gene clusters, which are directly involved in EET across the bacterial outer membrane, in the EET of . In addition to their essential roles, these gene clusters also play distinct, overlapping, and compensatory roles in the EET of . The distinct roles of the gene clusters enable to mediate EET to a diverse group of electron acceptors for anaerobic respirations. The overlapping and compensatory roles of the gene clusters enable to maintain and restore its EET capability for anaerobic growth when one or two of its three gene clusters are deleted from the genome.
为了研究它们在细胞外电子传递（EET）中的作用，革兰氏阴性菌 的孔蛋白-细胞色素（）基因簇 、 和 被删除。同时删除所有 基因簇的失败表明它们在 通过细胞外还原 Fe(III)-柠檬酸盐方面的重要作用。缺失 对细菌还原 Fe(III)-柠檬酸盐没有影响，但降低了细菌还原水铁矿的能力，并废除了阳极还原和直接种间电子转移（DIET）到 和 。虽然它对细菌还原 Fe(III)-柠檬酸盐没有影响，但缺失 延迟了水铁矿的还原，废除了阳极还原，并降低了 DIET。缺失 对 DIET 的影响很小，但降低了细菌对 Fe(III)-柠檬酸盐、水铁矿和阳极的还原。最重要的是，同时缺失 和 恢复了细菌对水铁矿和阳极的还原以及 DIET。在与 ΔΔ 共培养时，该双突变体中 的增强表达表明，该簇可能补偿了缺失 和 对 EET 功能的损害。因此，这些 基因簇在 的 EET 中发挥着必不可少的、独特的、重叠的和补偿的作用，很难将其描述为一些簇的缺失影响其他簇的表达。这些 基因簇的稳健性使 即使在其三个 基因簇中的两个被突变失活的情况下，也能介导不同的电子受体进行无氧生长的电子传递。这项研究的结果为细菌 EET 中 基因簇的作用提供了新的见解。
革兰氏阴性菌 具有环境和生物技术意义。对 独特生理学至关重要的是其细胞外电子传递（EET）能力。这项研究揭示了三个直接参与细菌外膜中 EET 的孔蛋白-细胞色素（）基因簇在 的 EET 中的强大作用。除了它们的基本作用外，这些基因簇在 的 EET 中还发挥着独特的、重叠的和补偿的作用。 基因簇的独特作用使 能够介导对一组不同的电子受体进行无氧呼吸。 基因簇的重叠和补偿作用使 能够在其三个 基因簇中的一个或两个从基因组中删除时，维持和恢复其进行无氧生长的 EET 能力。
