Cuticular Lipid and Defense Chemistry of Collembola

点击翻译按钮获取中文摘要

Collembola (springtails), a sister class of insects, show unusual chemistry in their constituents, which often differs from that of insects. Of particular interest are the unusual substances that make up the outermost lipid layer of the skin, the cuticle. This lipid layer is of particular importance in arthropods because its hydrophobic properties are essential in regulating the water balance, but it can also transmit information through its composition, serving as a chemical signal. While the insect cuticle is chemically dominated by relatively simple hydrocarbons, a much more complex chemistry with many unique and novel compounds is found in Collembola. These compounds can comprise long-chain terpenes, polymethyl-branched esters, and other previously unknown compounds. The project aims to elucidate the structure of these compounds, which can often only be obtained in small amounts due to the small size of Collembola, using mass spectrometric and infrared spectroscopic techniques as well as microderivatization of extracts. In order to verify the structure assignments, selected key compounds such as aromatic or branched terpenes or highly branched esters will be synthesized, which in some cases requires longer, complex syntheses. While the structures of some target compounds have been proposed by us here, a broader picture of epicuticle composition will be obtained by studying additional collembolan species. This will allow us to draw conclusions about the evolution of the chemistry of the cuticle of arthropods, comparing the results with those of insects and arachnids that we have studied independently. In order to be able to study further Collembola, a network has been established with biologists who will provide us with more species for the planned analyses. Defense compounds are used by a variety of Collembola as an additional defense mechanism besides the jumping fork. These compounds are also often only known from springtails. In addition to cuticular extracts, existing or newly obtained biological material can be used to obtain extracts containing more polar secondary metabolites. Within the scope of the investigations, these will also be analyzed. Some alkaloids have already been found and will be strucutrally defined by syntheses. By studying more species, it will be possible to determine how widespread chemical defense strategies are in Collembola and which biosynthetic pathways are used by them. This is of fundamental importance for understanding the ecology of these small but important arthropods. Since the cuticle of springtails is extremely water repellent, the synthesized compounds will be tested for their hydrophobic properties. The antimicrobial effect of the defense substances will also be evaluated.