Institute of Entomology, Biology Centre, CAS, and Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic; Faculty of Agriculture, University of Cairo, Giza, Egypt.
Institute of Experimental Biology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
J Insect Physiol. 2018 May-Jun;107:167-174. doi: 10.1016/j.jinsphys.2018.04.002. Epub 2018 Apr 5.
This study examined how adipokinetic hormone (AKH) and adenosine affect defense responses in Drosophila melanogaster larvae infected with entomopathogenic nematodes (EPN, Steinernema carpocapsae and Heterorhabditis bacteriophora). Three loss-of-function mutant larvae were tested: Akh, AdoR (adenosine receptor), and Akh AdoR. Mortality decreased in all mutants post-EPN infection compared with the control (w). Additionally, co-application of external AKH with EPN significantly increased mortality beyond rates observed in EPN-only treatment, while also elevating carbon dioxide production, a measure of metabolism. Furthermore trehalose levels increased in both w and Akh larvae post-EPN infection, but the latter group exhibited a lower increase and total trehalose levels. Interestingly, baseline trehalose was relatively high in untreated AdoR and Akh AdoR mutants, with levels remaining unaffected by infection. Infection also elevated haemolymph lipid content overall, but the different mutations did not substantially influence this change. In contrast, haemolymph protein content dropped after EPN infection in all tested groups, but this decline was more intense among Akh. In uninfected larvae mutations decreased antioxidative capacity in Akh and increased in AdoR, however, its post-infection increases were similar in all mutants, suggesting that antioxidant response in Drosophila involves mechanisms also beyond AKH and adenosine. Furthermore, AKH application in w larvae significantly increased movement distance and percentage of larval activity, but reduced velocity. Mutations of Akh and AdoR did not strongly affect locomotion.
这项研究探讨了脂肪激活激素 (AKH) 和腺苷如何影响感染昆虫病原线虫 (EPN，斯氏线虫和霍氏异小杆线虫) 的黑腹果蝇幼虫的防御反应。测试了三种功能丧失突变体幼虫：Akh、AdoR（腺苷受体）和 AkhAdoR。与对照 (w) 相比，所有突变体在 EPN 感染后死亡率均降低。此外，与仅 EPN 处理相比，外源性 AKH 与 EPN 共同应用显著增加了死亡率，同时还提高了二氧化碳的产生，这是代谢的一种衡量标准。此外，在 EPN 感染后，w 和 Akh 幼虫的海藻糖水平均升高，但后者的增加幅度较低，总海藻糖水平也较低。有趣的是，未处理的 AdoR 和 AkhAdoR 突变体的基础海藻糖水平相对较高，且不受感染的影响。感染还总体上提高了血淋巴脂质含量，但不同的突变并没有显著影响这种变化。相比之下，在所有测试组中，EPN 感染后血淋巴蛋白含量均下降，但 Akh 组下降更为剧烈。在未感染的幼虫中，Akh 中的突变降低了抗氧化能力，而在 AdoR 中则增加了抗氧化能力，然而，其感染后的增加在所有突变体中相似，这表明果蝇的抗氧化反应涉及 AKH 和腺苷以外的机制。此外，在 w 幼虫中应用 AKH 显著增加了运动距离和幼虫活动的百分比，但降低了速度。Akh 和 AdoR 的突变对运动能力没有强烈影响。
