Decay in juvenile hormone biosynthesis by insect corpus allatum after nerve transection
Decay in juvenile hormone biosynthesis by insect corpus allatum after nerve transection
复制标题
神经横断后昆虫幼体保幼激素生物合成的衰减
作者：
S. Tobe;C. S. Chapman;G. E. Pratt
昆虫咽体（CA）合成和释放保幼激素（JH）的能力被认为是由各种神经和体液的刺激和抑制性质的影响所控制的。在最后一个龄期的Galleria mellonella，CA刺激神经激素（allatotropin）起源于大脑的内侧神经分泌细胞，并在龄期的早期部分操作已被提出2，4。在龄期的后期，JH的合成和/或释放受到源自大脑并通过神经连接到达CA的神经冲动的抑制2。JH合成的类似神经抑制被认为在成虫Pyrrhocoris apterus 5和蟑螂Leucophaea maderae 6和Diploptera punctata 7中起作用，因为咽侧体神经1（NCA 1）的部分似乎激活CA。在直翅目昆虫，埃及蝗和飞蝗中也提出了一种来自大脑间部内侧神经分泌细胞的神经激素因子，它引起CA的激活8。在其他直翅目，Schistocerca sp.，已经提出了完整的NCA 1对于CA激活的必要性，表明直接的刺激性神经影响而不是抑制性影响或体液刺激9，10。因此，不同昆虫中控制JH生物合成的因素尚不清楚。在这里，我们表明，NCA 1节的破坏在第一生殖营养周期的沙漠蝗虫Schistocerca gregaria的结果在一个快速和可预测的下降的CA合成JH的能力。NCA-1片段对JH生物合成的影响在3 h内即可检测到.
THE ability of the insect corpus allatum (CA) to synthesise and release juvenile hormone (JH) is believed to be controlled by various neural and humoral influences of both stimulatory and inhibitory nature1. In last instar Galleria mellonella, a CA stimulatory neurohormone (allatotropin) originating in the medial neurosecretory cells of the brain and operating during the early part of the instar has been proposed2,4. In the later part of the instar the synthesis and/or release of JH is inhibited by nervous impulses originating in the brain and reaching the CA through nervous connections2. A similar nervous inhibition of JH synthesis is thought to operate in adult Pyrrhocoris apterus5 and in the cockroaches Leucophaea maderae6 and Diploptera punctata7, because section of the nervi corporis allati 1 (NCA 1) seems to activate the CA. A neurohormonal factor from the medial neurosecretory cells of the pars intercerebralis which causes the activation of the CA has also been proposed in the orthopterans, Anacridium aegyptium and Locusta migratoria8. In still other Orthoptera, Schistocerca sp., the necessity for intact NCA 1 for activation of the CA has been suggested, indicating a direct stimulatory neural influence rather than an inhibitory influence or a humoral stimulation9,10. Thus the factors controlling JH biosynthesis in different insect species are not clear. We show here that disruption of the NCA 1 by section during the first gonotrophic cycle of the desert locust Schistocerca gregaria results in a rapid and predictable decline in the ability of the CA to synthesise JH. The effect of section of the NCA 1 on JH biosynthesis is detectable within 3 h.