Molecular physiology of pumiliotoxin sequestration in a poison frog

Poison frogs bioaccumulate alkaloids for chemical defense from their arthropod diet. Although many alkaloids are accumulated without modification, some poison frog species can metabolize pumiliotoxin (PTX 251D) into the more potent allopumiliotoxin (aPTX 267A). Despite extensive research characterizing the chemical arsenal of poison frogs, the physiological mechanisms involved in the sequestration and metabolism of individual alkaloids remain unclear. We first performed a feeding experiment with the Dyeing poison frog (Dendrobates tinctorius) to ask if this species can metabolize PTX 251D into aPTX 267A and what gene expression changes are associated with PTX 251D exposure in the intestines, liver, and skin. We found that D. tinctorius can metabolize PTX 251D into aPTX 267A, and that PTX 251D exposure changed the expression level of genes involved in immune system function and small molecule metabolism and transport. To better understand the functional significance of these changes in g...毒蛙通过取食节肢动物饵料生物富集生物碱，以此构建化学防御体系。尽管多数生物碱可不经修饰直接被富集，但部分毒蛙物种能够将箭毒蛙毒素（pumiliotoxin, PTX 251D）代谢为活性更强的别箭毒蛙毒素（allopumiliotoxin, aPTX 267A）。尽管已有大量研究对毒蛙的化学防御成分库进行了系统表征，但针对单一生物碱的蓄积与代谢所涉及的生理机制仍不明晰。本研究首先以染色箭毒蛙（*Dendrobates tinctorius*）为实验对象开展饲喂实验，旨在探究该物种能否将PTX 251D代谢为aPTX 267A，以及PTX 251D暴露会在肠道、肝脏与皮肤中引发哪些基因表达变化。研究结果显示，染色箭毒蛙确实可将PTX 251D代谢为aPTX 267A，且PTX 251D暴露会改变与免疫系统功能、小分子代谢及转运相关的基因表达水平。为进一步阐明此类基因表达变化的功能意义……