Manganese (Mn²⁺) is an essential trace element within organisms spanning the entire tree of life. In this review, we provide an overview of Mn²⁺ transport and the regulation of its homeostasis in bacteria, with a focus on its functions beyond being a co-factor for enzymes. Crucial differences in Mn²⁺ homeostasis exist between bacterial species that can be characterized to have iron- or manganese-centric metabolism. Highly iron-centric species require minimal Mn²⁺ and mostly use it as a mechanism to cope with oxidative stress. As a consequence, tight regulation of Mn²⁺ uptake is required, while organisms that use both Fe²⁺ and Mn²⁺ need other layers of regulation for maintaining homeostasis. We will focus in detail on manganese-centric bacterial species, in particular lactobacilli, that require little to no Fe²⁺ and use Mn²⁺ for a wider variety of functions. These organisms can accumulate extraordinarily high amounts of Mn²⁺ intracellularly, enabling the non-enzymatic use of Mn²⁺ for decomposition of reactive oxygen species while simultaneously functioning as a mechanism of competitive exclusion. We further discuss how Mn²⁺ accumulation can provide both beneficial and pathogenic bacteria with advantages in thriving in their niches.

中文翻译：

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锰在细菌中的调控和独特的生理作用

锰 (Mn ²⁺ ) 是贯穿整个生命之树的生物体内必不可少的微量元素。在这篇综述中，我们概述了 Mn ²⁺转运及其在细菌中的稳态调节，重点关注其作为酶辅助因子之外的功能。^{Mn 2+}稳态的关键差异存在于可以表征为具有以铁或锰为中心的代谢的细菌物种之间。高度以铁为中心的物种需要最少的 Mn ²⁺并且主要将其用作应对氧化应激的机制。因此，需要严格调节 Mn ²⁺的吸收，而同时使用 Fe ²⁺和 Mn ^{2+的生物体}需要其他层面的监管来维持体内平衡。我们将详细关注以锰为中心的细菌物种，特别是乳酸杆菌，它们几乎不需要甚至不需要 Fe ²⁺并且使用 Mn ²⁺来实现更广泛的功能。这些生物体可以在细胞内积累异常大量的 Mn ^{2+ ，从而使 Mn 2+}能够非酶促地用于分解活性氧，同时充当竞争排斥机制。我们进一步讨论了 Mn ²⁺的积累如何为有益菌和病原菌提供优势，使其在其生态位中茁壮成长。