Departments of Pathology, Microbiology and Immunology and of Pediatrics, Vanderbilt University School of Medicine and Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
Curr Opin Microbiol. 2021 Jun;61:124-132. doi: 10.1016/j.mib.2021.04.002. Epub 2021 May 5.
Amphibian populations around the world have been affected by two pathogenic fungi within the phylum Chytridiomycota. Batrachochytrium dendrobatidis (Bd) has infected hundreds of species and led to widespread declines and some species extinctions. Batrachochytrium salamandrivorans (Bsal) has devastated some native European salamanders, especially the iconic fire salamanders (Salamandra salamandra). Comparative genomic studies show that Bd is more diverse and widespread than previously thought, and global lineages occur together allowing for the development of hybrid lineages. New studies raise the concern of greater pathogenesis if both Bd and Bsal infect the same host. Although amphibians possess robust immune defenses, co-infected and many single-infected hosts seem unable to mount effective immune responses. A strong defense may actually be harmful. Analysis of Bd and Bsal secretions documents small metabolites that signal high density to limit their growth and to suppress adaptive immune defenses, thus enabling a stealth presence in the skin compartment.
全世界的两栖动物种群受到了壶菌门中的两种病原真菌的影响。蛙壶菌（Bd）感染了数百种物种，导致广泛的减少和一些物种灭绝。蛙形短头蟾菌（Bsal）已经摧毁了一些本地的欧洲蝾螈，尤其是标志性的火蝾螈（Salamandra salamandra）。比较基因组研究表明，Bd 比以前认为的更加多样化和广泛分布，全球谱系共同出现，允许形成杂交谱系。新的研究增加了如果 Bd 和 Bsal 同时感染同一宿主，会导致更大的发病机制的担忧。尽管两栖动物具有强大的免疫防御能力，但同时感染和许多单一感染的宿主似乎无法产生有效的免疫反应。强大的防御实际上可能是有害的。对 Bd 和 Bsal 分泌物的分析记录了一些小代谢物，这些代谢物发出高密度信号，以限制它们的生长并抑制适应性免疫防御，从而使它们能够在皮肤隔室中悄然存在。
