Insect cytokine growth-blocking peptide (GBP) regulates insect development
Insect cytokine growth-blocking peptide (GBP) regulates insect development
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DOI：
10.1303/aez.2006.545
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发表时间：
2006-11
影响因子：
1.3
通讯作者：
Y. Hayakawa
中科院分区：
文献类型：
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作者：
Y. Hayakawa
生长阻滞肽(GBP)首先从寄主粘虫血淋巴中分离出来，寄生在粘虫幼虫末龄阶段，被寄生的粘虫Cotesia kariyai阻止生长。对GBP生长迟缓机理的研究表明，血淋巴中GBP的滴度与多巴胺水平同步波动：GBP和多巴胺的峰值与幼虫暂时停止活动和取食的每个蜕皮期相吻合。在粘虫幼虫体内注射银杏叶提取物可引起血淋巴中多巴胺浓度的升高。在暴露于各种应激条件下的昆虫中，也观察到多巴胺的升高，如寄生和冷藏。这些结果，再加上多巴胺本身抑制幼虫生长的事实，表明GBP通过提高多巴胺水平而导致生长迟缓。此外，我们还证明了短日照诱导滞育的影响也提高了甘蓝粘虫血淋巴和脑-中枢神经系统(BR-CNS)中的多巴胺浓度。多巴胺水平的升高导致了幼虫滞育的发生。因此，我们提出GBP-多巴胺系统有助于控制昆虫的生长速度。最近我们和其他实验室的研究发现，在不同的昆虫物种中有10多个同源肽。这些多肽具有多种功能：幼虫生长迟缓、麻痹诱导、细胞增殖、免疫细胞刺激和心脏加速。由此可见，GBP本身发挥着大部分的这些功能，因此，昆虫中广泛存在的GBP和GBP样肽应该被认为是具有多种功能的昆虫细胞因子。
Growth-blocking peptide (GBP) was first identified in the hemolymph of the host armyworm, Pseudaletia separata, whose growth is halted in the last instar larval stage by parasitization with the parasitoid wasp, Cotesia kariyai. Studies on the mechanism of growth retardation by GBP revealed that GBP titers in hemolymph fluctuate synchronously with dopamine levels: GBP and dopamine peaks coincide with each larval molt period, during which larvae temporarily cease moving and feeding. The fact that GBP induced the elevation of dopamine concentration in the hemolymph was demonstrated in armyworm larvae by GBP injection. Dopamine elevation was also observed in insects exposed to various stress conditions such as parasitization and chilling. These results, together with the fact that dopamine itself inhibits larval growth, indicate that GBP induces growth retardation via the elevation of dopamine levels. Further, we demonstrated that the diapause-inducing influence of short day length also elevates dopamine concentrations in hemolymphs and the brain-central nervous system (Br-CNS) of the cabbage armyworm, Mamestra brassicae. The elevation of dopamine levels contributes to the onset of pupal diapause. We therefore proposed that a GBP-dopamine system contributes to the control of growth rates in insects. Recent studies by ourselves and other laboratories have found more than 10 homologous peptides in various insect species. These peptides have diverse functions: larval growth retardation, paralysis induction, cell proliferation, immune cell stimulation and cardioacceleration. As demonstrated, GBP itself exerts most of these functions, so it is reasonable to conclude that GBP and GBP-like peptides widely present in insects should be regarded as insect cytokines with a variety of functions.