Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo Bunkyo-ku, Tokyo, Japan.
Front Endocrinol (Lausanne). 2012 Jan 18;3:3. doi: 10.3389/fendo.2012.00003. eCollection 2012.
In our previous report, we demonstrated the possibility that various regulatory neuropeptides influence feeding behavior in the silkworm, Bombyx mori. Among these feeding-related neuropeptides, short neuropeptide F (sNPF) exhibited feeding-accelerating activity when injected into B. mori larvae. Like other insect sNPFs, the deduced amino acid sequence of the cDNA encoding the sNPF precursor appears to produce multiple sNPF and sNPF-related peptides in B. mori. The presence of three sNPFs, sNPF-1, sNPF-2, and sNPF-3, in the brain of B. mori larvae was confirmed by direct MALDI-TOF mass spectrometric profiling. In addition, all three sNPFs are present in other larval ganglia. The presence of sNPF mRNA in the central nervous system (CNS) was also confirmed by Reverse transcription-polymerase chain reaction. Semi-quantitative analyses of sNPFs in the larval brain using matrix-assisted laser desorption ionization time-of-flight mass spectrometry further revealed that brain sNPF levels decrease in response to starvation, and that they recover with the resumption of feeding. These data suggest that sNPFs were depleted by the starvation process. Furthermore, food deprivation decreased the transcriptional levels of the sNPF receptor (BNGR-A10) in the brain and CNS, suggesting that the sNPF system is dependent on the feeding state of the insect and that the sNPF system may be linked to locomotor activity associated with foraging behavior. Since the injection of sNPFs accelerated the onset of feeding in B. mori larvae, we concluded that sNPFs are strongly related to feeding behavior. In addition, semi-quantitative MS analyses revealed that allatostatin, which is present in the larval brain, is also reduced in response to starvation, whereas the peptide level of Bommyosuppressin was not affected by different feeding states.
在我们之前的报告中，我们证明了各种调节神经肽可能影响家蚕（Bombyx mori）的摄食行为。在这些与摄食相关的神经肽中，短神经肽 F（sNPF）注射到家蚕幼虫中时表现出促进摄食的活性。与其他昆虫 sNPFs 一样，编码 sNPF 前体的 cDNA 推断的氨基酸序列似乎在家蚕中产生多种 sNPF 和 sNPF 相关肽。通过直接 MALDI-TOF 质谱分析，证实了家蚕幼虫脑中存在三种 sNPF，即 sNPF-1、sNPF-2 和 sNPF-3。此外，这三种 sNPF 都存在于其他幼虫神经节中。通过反转录聚合酶链反应也证实了 sNPF mRNA 存在于中枢神经系统（CNS）中。使用基质辅助激光解吸电离飞行时间质谱对半定量分析幼虫脑中的 sNPF 进一步表明，脑 sNPF 水平随饥饿而降低，并随摄食恢复而恢复。这些数据表明 sNPF 被饥饿过程消耗。此外，食物剥夺降低了脑中和 CNS 中 sNPF 受体（BNGR-A10）的转录水平，表明 sNPF 系统依赖于昆虫的摄食状态，并且 sNPF 系统可能与觅食行为相关的运动活性有关。由于 sNPF 的注射加速了家蚕幼虫摄食的开始，我们得出结论，sNPF 与摄食行为密切相关。此外，半定量 MS 分析表明，存在于幼虫脑中的促前胸腺激素抑制素（allatostatin）也随饥饿而减少，而 Bommyosuppressin 的肽水平不受不同摄食状态的影响。
