School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
PLoS Genet. 2012 Jun;8(6):e1002779. doi: 10.1371/journal.pgen.1002779. Epub 2012 Jun 28.
Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood and other adult bees inside the nest, while older bees (foragers) forage outside for pollen, a protein/lipid source, or nectar, a carbohydrate source. The workers' transition from nursing to foraging and their foraging preferences correlate with differences in gustatory perception, metabolic gene expression, and endocrine physiology including the endocrine factors vitellogenin (Vg) and juvenile hormone (JH). However, the understanding of connections among social behavior, energy metabolism, and endocrine factors is incomplete. We used RNA interference (RNAi) to perturb the gene network of Vg and JH to learn more about these connections through effects on gustation, gene transcripts, and physiology. The RNAi perturbation was achieved by single and double knockdown of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor and Vg, respectively. The double knockdown enhanced gustatory perception and elevated hemolymph glucose, trehalose, and JH. We also observed transcriptional responses in insulin like peptide 1 (ilp1), the adipokinetic hormone receptor (AKHR), and cGMP-dependent protein kinase (PKG, or "foraging gene" Amfor). Our study demonstrates that the Vg-JH regulatory module controls changes in carbohydrate metabolism, but not lipid metabolism, when worker bees shift from nursing to foraging. The module is also placed upstream of ilp1, AKHR, and PKG for the first time. As insulin, adipokinetic hormone (AKH), and PKG pathways influence metabolism and gustation in many animals, we propose that honey bees have conserved pathways in carbohydrate metabolism and conserved connections between energy metabolism and gustatory perception. Thus, perhaps the bee can make general contributions to the understanding of food-related behavior and metabolic disorders.
蜜蜂（Apis mellifera）提供了一个研究社会和与食物相关行为的系统。一个工蜂群体执行与年龄相关的任务：年轻的蜜蜂（护士）通常在巢内喂养幼蜂和其他成年蜜蜂，而年长的蜜蜂（觅食者）则在外面寻找花粉、蛋白质/脂质来源或花蜜、碳水化合物来源。工蜂从护理到觅食的转变及其觅食偏好与味觉感知、代谢基因表达和内分泌生理学（包括内分泌因素卵黄蛋白原（Vg）和保幼激素（JH））的差异相关。然而，对社会行为、能量代谢和内分泌因素之间的联系的理解并不完整。我们使用 RNA 干扰（RNAi）扰乱 Vg 和 JH 的基因网络，通过对味觉、基因转录物和生理学的影响来更多地了解这些联系。RNAi 干扰是通过单个和双基因敲低 ultraspiracle（usp）和 vg 基因来实现的，usp 和 vg 基因分别编码一个假定的 JH 受体和 Vg。双基因敲低增强了味觉感知，并提高了血淋巴葡萄糖、海藻糖和 JH 的水平。我们还观察到胰岛素样肽 1（ilp1）、肾上腺素能激素受体（AKHR）和环鸟苷酸依赖性蛋白激酶（PKG，或“觅食基因”Amfor）的转录反应。我们的研究表明，当工蜂从护理转变为觅食时，Vg-JH 调节模块控制碳水化合物代谢的变化，但不控制脂质代谢。该模块还首次位于 ilp1、AKHR 和 PKG 之前。由于胰岛素、肾上腺素能激素（AKH）和 PKG 途径在许多动物中影响代谢和味觉，我们提出蜜蜂在碳水化合物代谢中具有保守途径，并且在能量代谢和味觉感知之间具有保守联系。因此，蜜蜂可能对理解与食物相关的行为和代谢紊乱做出了一般性贡献。
