Study of neural networks and control substances for insect photoperiodism

本研究从形态学上研究了果蝇Protophormia terraenoptera光周期调节生殖滞育机制中的神经网络和控制物质。通过对小型PDF神经元（昼夜节律钟神经元）与侧部（滞育控制神经元）和大脑间部（对生殖起重要作用的神经元）之间的神经联系的研究，我们获得了以下结果：光周期性神经网络的形态学分析：在脑内的5组细胞中发现了PERIOD免疫反应。在5组中，2组包括小型PDF神经元，用抗PERIOD和抗PDF（色素分散因子）抗血清双重标记。手术切除小型PDF神经元的胞体区域破坏了光周期性，表明昼夜节律钟神经元参与了光周期性。免疫细胞化学和回填法将外侧部分为两种类型和6种类型的神经元。结果表明，在脑间部和外侧部，FMRFamide、PDF、cystokinin和corazonin均呈阳性反应，光周期反应的神经网络对照物质：直接MALDI-TOF MS和ESI-Q-Tof MS和MS/MS显示，在脑间部有myosuppressin和SIFamide，在外侧部有corazonin和corazonin相关肽。实时荧光定量PCR分析显示，光周期条件下，周期和无时间的两个生物钟基因的表达量每天都有波动，但长日照和短日照条件下的差异不明显，生物钟基因是如何参与光周期的还有待进一步研究。

This study morphologically examined neural networks and control substances involved in photoperiodic mechanisms regulating reproductive diapause in the blow fly Protophormia terraenovae. We obtained following results by focusing on neural connections from small type PDF neurons (circadian clock neurons) to pars lateralis neurons (diapause controlling neurons) and pars intercerebralis neurons important for reproduction.Morphological analysis of neural networks for photoperiodism: PERIOD-immunoreactivity was found in 5 groups of cells in the brain. Among the 5 groups two including small type PDF neurons were double-labeled with anti- PERIOD and anti-PDF (pigment-dispersing factor) antisera. Surgical ablation of the somata region of small type PDF neurons disrupted photoperiodism, suggesting that circadian clock neurons were involved in photoperiodism. Immunocytochemistry and backfills classified two types in the pars lateralis and 6 types of pars lateralis neurons. In the pars intercerebralis neurons, FMRFamide-immunoreacrtivity and in the pars lateralis FMRFamide-, PDF-, cholescystokinin-, corazonin-immunoreacrtivity were found.Control substances in neural networks for photoperiodism: Direct MALDI-TOF MS, and ESI-Q-Tof MS and MS/MS suggested that myosuppressin and SIFamide were present in the pars intercerebralis, corazonin and a corazonin-related peptide in the pars lateralis. Real-time PCR analysis revealed daily fluctuations in the expression of two circadian clock genes period and timeless under photoperiodic conditions, but no differences between long-day and short-day conditions were found. It has to be determined how the circadian clock genes are involved in photoperiodism.