Identification and synthesis of volatile compounds from pheromone glands of tropical frogs

两栖类的挥发性化学信号目前还没有得到很好的研究。非洲蛙科Mantellidae和Hyperoliidae的喉腺和股腺的化学性质将是该项目的重点。这两个家族的雄性都有这种含有挥发性化合物的腺体。这些通常复杂的腺体花束的化学性质是不寻常的。大环内酯占主导地位的Mantellidae，而倍半萜是hyperoliid喉腺的主要成分。其中许多化合物是新的，具有前所未有的结构。在该项目中，将使用有机分析方法进行腺体成分的结构解析，并通过合成验证衍生的结构建议。低量的材料和复杂的花束通常禁止使用常见的核磁共振（NMR）光谱方法进行结构解析。因此，将使用以前未以这种方式组合的不同方法来进行压盖成分的结构验证。除了经典的方法，如气相色谱/质谱（GC/MS）和提取物的微量衍生化，还将使用高灵敏度气相色谱/红外光谱（GC/FT-IR）和通过密度泛函理论方法（DFT）计算红外光谱。此外，倍半萜烃将被还原或氧化转化，所得材料将与衍生提取物进行比较。这个过程将导致必须通过有机合成验证的结构建议。后续的合成将为行为测试和其他生物测定提供材料。 在第一个资助期间，特别是地幔进行了调查。超流体将是第二个供资期的主要重点。这些青蛙的喉腺只在繁殖季节受到神经支配。这开启了对这些腺体进行转录组学分析以寻找推定的倍半萜环化酶的可能性。然后，这些环化酶将协同异源表达，以表征迄今为止研究不足的脊椎动物倍半萜环化酶。在第一个资助期内，研究了这两个科的约80个物种，并鉴定和合成了几个新结构。这些结果是第二个供资期的基础。在对许多未知的腺体成分进行结构鉴定后，比较分析将深入了解这些高度多样化、物种丰富的青蛙家族中通讯化学的进化、功能和多样化。

Volatile chemical signals of Amphibia are currently not well investigated. The chemistry of gular and femoral glands of the African frog families Mantellidae and Hyperoliidae will be in the focus of the project. Males of both families possess such glands that contain volatile compounds. The chemistry of these often complex gland bouquets is unusual. Macrocyclic lactones dominate in the Mantellidae, while sesquiterpenes are the major components of the hyperoliid gular glands. Many of these compounds are new and have unprecedented structures. In the project the structural elucidation of the gland constituents will be performed using organic-analytical methods and the derived structural proposals will be verified by synthesis. The low amounts of material and the complex bouquets often prohibit the use of common nuclear magnetic resonance (NMR) spectroscopic methods for structural elucidation. Therefore, different methods will be used that have not been combined in this manner before for structure verification of gland constituents. Besides classical methods like gas chromatography/mass spectrometry (GC/MS) and microderivatizations of extracts, highly sensitive gas chromatography/infrared spectroscopy (GC/FT-IR) and calculation of infrared spectra by density functional theory methods (DFT) will be used. In addition, sesquiterpene hydrocarbons will be transformed reductively or oxidatively and the resulting material will be compared to derivatized extracts. This procedure will lead to structural proposals that have to be verified by organic synthesis. The follow-up synthesis will deliver material for behavioral testing and for other biological assays. During the first funding period especially mantellids were investigated. The hyperoliids will be the major focus of the second funding period. The gular glands of these frogs are only innervated during the breeding season. This opens the possibility to perform transcriptomic analysis of these glands to look for putative sesquiterpene cyclases. These cylases will then be heterologously expressed in cooperation to enable characterization of so far poorly investigated vertebrate sesquiterpene cyclases.About 80 species of both families were investigated during the first funding period and several new structures were identified and synthesized. These results are the basis for the second funding period. After structural identification of many of the unknown gland constituents, a comparative analysis will give insight into evolution, function and diversification of the communication chemistry in these highly diversified, species rich frog families.