Data from: Out in the cold and sick: low temperatures and fungal infections impair a frog's skin defenses

Amphibians worldwide continue to battle an emerging infectious disease, chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd). Southern leopard frogs, Rana sphenocephala, are known to become infected with this pathogen, yet they are considered 'of least concern' for declines due to chytridiomycosis. Previous studies have shown that R. sphenocephala secretes four antimicrobial peptides (AMPs) onto their skin which may play an important role in limiting susceptibility to chytridiomycosis. Here we examined the (1) effects of temperature and AMP depletion on infections with Bd and (2) effects of temperature and Bd infection on the capacity to secrete AMPs in juvenile leopard frogs. Pathogen burden and mortality were greater in frogs exposed to Bd at low temperature but did not increase following monthly AMP depletion. Both low temperature and Bd exposure reduced the capacity of juvenile frogs to restore peptides after monthly depletions. Frogs held at 14°C were poorly able to restore peptides in comparison with those at 26°C. Frogs held at 26°C were better able to restore their peptides, but when exposed to Bd, this capacity was significantly reduced. These results strongly support the hypothesis that both colder temperatures and Bd infections impair the capacity of juvenile frogs to produce and secrete AMPs, an important component of their innate defense against chytrid fungi and other pathogens. Thus, in the face of unpredictable climate changes and enzootic pathogens, assessments of disease risk should consider the potential for effects of environmental variation and pathogen exposure on the quality of host defenses.

全球两栖动物仍在与新出现的传染性疾病——壶菌病（chytridiomycosis）持续抗争，该病由蛙壶菌（Batrachochytrium dendrobatidis, Bd）引发。已知南方豹蛙（Rana sphenocephala）可感染该病原菌，但学界将其因壶菌病导致种群衰退的风险归类为“无危”。既往研究显示，南方豹蛙能在皮肤表面分泌四种抗菌肽（antimicrobial peptides, AMPs），这类物质可能在限制其对壶菌病的易感性方面发挥关键作用。本研究以幼豹蛙为对象，开展了两项探究：（1）温度与抗菌肽耗竭对蛙壶菌感染的影响；（2）温度与蛙壶菌感染对幼蛙分泌抗菌肽能力的影响。研究发现，低温环境下暴露于蛙壶菌的幼蛙，其病原体负荷与死亡率均更高，但每月一次的抗菌肽耗竭并未加剧该情况。低温环境与蛙壶菌暴露均会削弱幼蛙在经历每月抗菌肽耗竭后的肽类恢复能力。与26℃环境中的幼蛙相比，14℃环境下的个体几乎无法恢复肽类分泌能力。26℃环境下的幼蛙原本具备更强的肽类恢复能力，但当其暴露于蛙壶菌后，该能力会出现显著下降。上述结果有力支持了下述假说：低温与蛙壶菌感染均会损害幼蛙产生并分泌抗菌肽的能力，而抗菌肽是其抵御壶菌及其他病原菌的先天防御系统的重要组成部分。因此，在面临难以预测的气候变化与地方性病原菌威胁时，疾病风险评估应考虑环境变化与病原菌暴露对宿主防御能力质量的潜在影响。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于低温和蛙壶菌（Batrachochytrium dendrobatidis）感染对南方豹蛙（Rana sphenocephala）皮肤防御能力的影响。研究发现，低温（14°C）和病原体暴露会显著削弱幼蛙恢复抗菌肽（AMPs）的能力，从而增加感染风险和死亡率，而较高温度（26°C）下恢复能力较好但仍受Bd抑制。数据集包含生存率、Bd负载和抗菌肽检测的实验数据，旨在评估环境变化和病原体暴露对宿主防御质量的影响。