Section of Ecology, Behavior, and Evolution, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, MC0116, La Jolla, CA 92093, USA.
Sci Rep. 2017 Oct 26;7(1):14144. doi: 10.1038/s41598-017-14702-4.
Nosema ceranae is a pervasive and widespread honey bee pathogen that is associated with colony declines and has recently been shown to infect larval honey bees. In adult bees, Nosema infection is known to alter levels of a key protein, vitellogenin (Vg), which is necessary for egg-laying in queens, brood food production in workers, and proper immune function in all female bees. We therefore tested the effects of larval worker infection on hemolymph Vg titers. In 1-day old adult workers that were infected as larvae with 10,000 (10 K) or 40,000 (40 K) live N. ceranae spores/bee, Vg titers were significantly elevated by + 83% and + 73%, respectively, as compared to controls. At 7 days of adult age, Vg remained significantly elevated (+ 68%) in 10 K treated workers as compared to control workers. Nosema infection decreased total hemolymph protein titers in 1 and 7-day old adult bees (-50% in the 10 K and 40 K treated bees). Bees infected as larvae also had a more queen-like sting morphology. They developed slightly but significantly fewer barbs on their stings (-7% in the 40K-treated bees). Higher Vg levels are associated with younger bees. Thus, elevated Vg levels could delay normal age polyethism and disrupt colony balance.
微孢子虫是一种普遍存在且广泛分布的蜜蜂病原体，与蜂群衰退有关，最近已被证明可感染幼虫蜜蜂。在成年蜜蜂中，已知微孢子虫感染会改变一种关键蛋白质——卵黄原蛋白（Vg）的水平，Vg 对蜂王产卵、工蜂幼虫食物生产和所有雌性蜜蜂的正常免疫功能至关重要。因此，我们测试了幼虫工蜂感染对血淋巴 Vg 滴度的影响。在 1 日龄成年工蜂中，幼虫期感染 10,000（10K）或 40,000（40K）个活的 N. ceranae 孢子/只，Vg 滴度分别显著升高了+83%和+73%，与对照组相比。在 7 日龄成年期，与对照组相比，10K 处理的工蜂 Vg 仍显著升高（+68%）。微孢子虫感染降低了 1 日龄和 7 日龄成年蜜蜂的总血淋巴蛋白滴度（10K 和 40K 处理的蜜蜂分别降低了 50%）。幼虫期感染的蜜蜂也具有类似蜂王的蜇刺形态。它们的蜇刺上的刺稍微但显著减少（40K 处理的蜜蜂减少了 7%）。较高的 Vg 水平与较年轻的蜜蜂有关。因此，升高的 Vg 水平可能会延迟正常的年龄多态现象并破坏群体平衡。
