One of the most thoroughly studied insect species, with respect to locomotion behavior, is the stick insect Carausius morosus. Although detailed information exists on premotor networks controlling walking, surprisingly little is known about neuropeptides, which are certainly involved in motor activity generation and modulation. So far, only few neuropeptides were identified from C. morosus or related stick insects. We performed a transcriptome analysis of the central nervous system to assemble and identify 65 neuropeptide and protein hormone precursors of C. morosus, including five novel putative neuropeptide precursors without clear homology to known neuropeptide precursors of other insects (Carausius neuropeptide-like precursor 1, HanSolin, PK-like1, PK-like2, RFLamide). Using Q Exactive Orbitrap and MALDI-TOF mass spectrometry, 277 peptides including 153 likely bioactive mature neuropeptides were confirmed. Peptidomics yielded a complete coverage for many of the neuropeptide propeptides and confirmed a surprisingly high number of heterozygous sequences. Few neuropeptide precursors commonly occurring in insects, including those of insect kinins and sulfakinins, could neither be found in the transcriptome data nor did peptidomics support their presence. The results of our study represent one of the most comprehensive peptidomic analyses on insects and provide the necessary input for subsequent experiments revealing neuropeptide function in greater detail.

中文翻译：

---

棒形虫（Carausius morosus）的转录组学和神经肽组学分析

就运动行为而言，最深入研究的昆虫物种之一是粘虫Carausius morosus。尽管在控制步行的运动前网络上有详细的信息，但令人惊讶的是，对神经肽的了解却很少，这肯定参与了运动活动的产生和调节。到目前为止，仅从极寒梭菌或相关的粘虫中鉴定出很少的神经肽。我们对中枢神经系统进行了转录组分析，以组装和鉴定65种桑蚕假丝酵母神经肽和蛋白激素前体，包括五个与其他昆虫的已知神经肽前体没有明显同源性的新型推定神经肽前体（Carausius）。神经肽样前体1，HanSolin，PK-like1，PK-like2，RFLamide）。使用Q Exactive Orbitrap和MALDI-TOF质谱分析，证实了277种肽，其中包括153种可能具有生物活性的成熟神经肽。肽组学产生了许多神经肽前肽的完全覆盖，并证实了令人惊讶地高数量的杂合序列。昆虫中常见的神经肽前体很少，包括昆虫激肽和磺胺激酶的神经肽前体在转录组数据中都找不到，肽组学也不能支持它们的存在。我们的研究结果代表了对昆虫的最全面的肽组分析之一，并为随后的实验提供了必要的输入，从而更详细地揭示了神经肽的功能。