Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP, Brazil;
Departamento de Zoologia e Centro de Aquicultura, Instituto de Biociências, Universidade Estadual Paulista, 13506-900 Rio Claro, SP, Brazil.
Proc Natl Acad Sci U S A. 2019 Feb 5;116(6):2124-2129. doi: 10.1073/pnas.1806834116. Epub 2019 Jan 22.
Amphibians are known to possess a wide variety of compounds stored in their skin glands. While significant progress has been made in understanding the chemical diversity and biological relevance of alkaloids, amines, steroids, and peptides, most aspects of the odorous secretions are completely unknown. In this study, we examined sexual variations in the volatile profile from the skin of the tree frog and combined culture and culture-independent methods to investigate if microorganisms might be a source of these compounds. We found that sesquiterpenes, thioethers, and methoxypyrazines are major contributors to the observed sex differences. We also observed that each sex has a distinct profile of methoxypyrazines, and that the chemical origin of these compounds can be traced to a sp. strain isolated from the frog's skin. This symbiotic bacterium was present in almost all individuals examined from different sites and was maintained in captive conditions, supporting its significance as the source of methoxypyrazines in these frogs. Our results highlight the potential relevance of bacteria as a source of chemical signals in amphibians and contribute to increasing our understanding of the role that symbiotic associations have in animals.
两栖动物的皮肤腺中储存着各种各样的化合物。尽管人们在生物碱、胺、类固醇和肽的化学多样性和生物相关性方面已经取得了重大进展，但大多数有气味的分泌物的方面仍然完全未知。在这项研究中，我们检查了树蛙皮肤挥发物谱的性别差异，并结合培养和非培养方法来研究微生物是否可能是这些化合物的来源。我们发现，倍半萜、硫醚和甲氧基吡嗪是导致观察到的性别差异的主要因素。我们还观察到，每一种性别都有独特的甲氧基吡嗪图谱，而且这些化合物的化学起源可以追溯到从青蛙皮肤中分离出来的 sp. 菌株。这种共生细菌存在于来自不同地点的几乎所有被检查的个体中，并在圈养条件下得以维持，这支持了它作为这些青蛙中甲氧基吡嗪来源的重要性。我们的研究结果强调了细菌作为化学信号源在两栖动物中的潜在相关性，并有助于增加我们对共生关系在动物中的作用的理解。
