Department of Microbiology, University of Tennessee, Knoxville, TN, United States.
Front Cell Infect Microbiol. 2019 Mar 29;9:81. doi: 10.3389/fcimb.2019.00081. eCollection 2019.
Iron is a transition metal utilized by nearly all forms of life for essential cellular processes, such as DNA synthesis and cellular respiration. During infection by bacterial pathogens, the host utilizes various strategies to sequester iron in a process termed, nutritional immunity. To circumvent these defenses, Gram-negative pathogens have evolved numerous mechanisms to obtain iron from heme. In this review we outline the systems that exist in several Gram-negative pathogens that are associated with heme transport and utilization, beginning with hemolysis and concluding with heme degradation. In addition, Gram-negative pathogens must also closely regulate the intracellular concentrations of iron and heme, since high levels of iron can lead to the generation of toxic reactive oxygen species. As such, we also provide several examples of regulatory pathways that control heme utilization, showing that co-regulation with other cellular processes is complex and often not completely understood.
铁是几乎所有生命形式用于基本细胞过程的过渡金属，例如 DNA 合成和细胞呼吸。在细菌病原体感染期间，宿主利用各种策略将铁隔离在称为营养免疫的过程中。为了规避这些防御，革兰氏阴性病原体已经进化出许多从血红素中获取铁的机制。在这篇综述中，我们概述了与血红素运输和利用相关的几种革兰氏阴性病原体中存在的系统，从溶血开始，以血红素降解结束。此外，革兰氏阴性病原体还必须严格调节细胞内铁和血红素的浓度，因为高水平的铁会导致有毒的活性氧的产生。因此，我们还提供了几个控制血红素利用的调控途径的例子，表明与其他细胞过程的共同调控是复杂的，并且通常还不完全了解。
