Immunosenescence in honey bees (Apis mellifera L.) is caused by intrinsic senescence and behavioral physiology
Immunosenescence in honey bees (Apis mellifera L.) is caused by intrinsic senescence and behavioral physiology
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DOI：
10.1016/j.exger.2019.02.005
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发表时间：
2019-05-01
影响因子：
3.9
通讯作者：
Paulino Simoes, Zila Luz
中科院分区：
文献类型：
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作者：
Lourenco, Anete Pedro;Martins, Juliana Ramos;Paulino Simoes, Zila Luz
年轻的工蜂（0至2-3周龄）在殖民地内执行任务，包括育雏护理（护理），而年长的工蜂在接下来的3-4周内进行觅食任务，此时内在的衰老程序在工蜂死亡时达到高潮。我们假设觅食蜂对免疫系统刺激的反应能力低于护士蜂，这种差异是由于觅食蜂的免疫反应效率低下。为了验证这一假设，我们使用了一个实验设计，使我们能够解耦的实足年龄和行为状态（护理/觅食）。测试了来自正常年龄人口统计学群体（其中工蜂随着年龄的增长自然地从哺乳过渡到觅食任务）和单队列群体设置（由执行哺乳或觅食任务的同龄工蜂组成）的工蜂在细菌注射后的存活率和免疫系统激活能力。抗微生物肽基因防御素-1（def-1）的表达用于评估免疫系统激活。然后我们检查了免疫反应是否包括衰老和行为相关基因表达的变化，特别是卵黄蛋白原（vg），保幼激素酯酶（jhe）和胰岛素样肽-1（ilp-1）。我们发现，不同年龄的蜜蜂在执行相同任务时，存活率存在显着差异。因此，我们的研究结果表明，蜜蜂的免疫反应受到内在衰老的负面影响。此外，与年龄无关，觅食者在细菌感染后的寿命比护士短，尽管两者都能够诱导def-1转录。在正常年龄群体中，采集蜂的免疫系统激活导致vg、jhe和ilp-1基因表达降低，而保育蜂则没有，表明年龄和行为对蜜蜂的免疫反应都有重要影响。通过解开年龄和行为对单群体的影响，我们发现vg，jhe和ilp-1对免疫系统刺激的反应与行为无关。年轻的蜜蜂能够比年长的蜜蜂产生更强的免疫反应，从而突出了年龄是免疫力的重要因素。总之，我们的研究结果为年龄和行为如何影响蜜蜂的免疫反应提供了新的见解。
Young honey bee workers (0 to 2-3 weeks old) perform tasks inside the colony, including brood care (nursing), whereas older workers undergo foraging tasks during the next 3-4 weeks, when an intrinsic senescence program culminates in worker death. We hypothesized that foragers are less able to react to immune system stimulation than nurse bees and that this difference is due to an inefficient immune response in foragers. To test this hypothesis, we used an experimental design that allowed us to uncouple chronological age and behavior status (nursing/foraging). Worker bees from a normal age demography colony (where workers naturally transit from nursing to foraging tasks as they age) and of a single-cohort colony setup (composed of same-aged workers performing nursing or foraging tasks) were tested for survival and capability of activation of the immune system after bacterial injection. Expression of an antimicrobial peptide gene, defensin-1 (def-1), was used to assess immune system activation. We then checked whether the immune response includes changes in the expression of aging- and behavior-related genes, specifically vitellogenin (vg), juvenile hormone esterase (jhe), and insulin-like peptide-1 (ilp-1). We found a significant difference in survival rate between bees of different ages but carrying out the same tasks. Our results thus indicate that the bees' immune response is negatively affected by intrinsic senescence. Additionally, independent of age, foragers had a shorter lifespan than nurses after bacterial infection, although both were able to induce def-1 transcription. In the normal age demography colony, the immune system activation resulted in a reduction in the expression of vg, jhe and ilp-1 genes in foragers, but not in the nurse bees, demonstrating that age and behavior are both important influences on the bees' immune response. By disentangling the effects of age and behavior in the single-cohort colony, we found that vg, jhe and ilp-1 response to immune system stimulation was independent of behavior. Younger bees were able to mount a stronger immune response than older bees, thus highlighting age as an important factor for immunity. Taken together, our results provide new insights into how age and behavior affect the honey bee's immune response.