Institut für Bienenkunde, Polytechnische Gesellschaft, Goethe University, Frankfurt Am Main, Germany.
Institute of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University, Frankfurt Am Main, Germany.
Sci Rep. 2024 Aug 6;14(1):18274. doi: 10.1038/s41598-024-68650-x.
Nursing honeybees produce brood food with millimolar concentrations of acetylcholine (ACh), which is synthesized through head gland secretions mixed with honey stomach contents. While we previously demonstrated the necessity of ACh for proper larval development, the dynamics of ACh levels throughout ontogenesis and their seasonal variations have remained unclear until now. Our HPLC analysis reveals dependencies of choline and ACh levels on larval development days (LDDs), influenced by seasonal (April-September) variations. Median ACh concentrations peak on LDD 2, declining significantly toward cell capping, while choline levels are lowest during the initial LDDs, rising markedly toward cell capping. Seasonal patterns show peak ACh levels from April to June and a low in August, paralleling choline's peak in July and low in August. This seasonality holds consistently across multiple years (2020-2022) and colonies, despite potential variations in colony performance and environmental conditions. Our analysis found no correlation between temperature, sunshine, precipitation, or favourable foraging days and ACh/choline levels, suggesting the involvement of additional factors. These findings underscore the seasonal fluctuation of ACh levels and its potential implications for the genetic programs governing winter bee development.
工蜂用毫摩尔浓度的乙酰胆碱（ACh）来生产幼虫食物，这种乙酰胆碱是通过头部腺体分泌的物质与蜜胃内容物混合而成的。虽然我们之前已经证明了 ACh 对幼虫正常发育的必要性，但直到现在，ACh 水平在整个个体发育过程中的动态及其季节性变化仍不清楚。我们的 HPLC 分析表明，胆碱和 ACh 水平依赖于幼虫发育天数（LDDs），受季节性（4 月至 9 月）变化的影响。ACh 浓度中位数在 LDD2 时达到峰值，在封盖细胞时显著下降，而胆碱水平在最初的 LDD 时最低，在封盖细胞时显著升高。季节性模式显示 ACh 水平在 4 月至 6 月达到峰值，8 月达到低谷，与 7 月的胆碱峰值和 8 月的胆碱低谷相吻合。尽管在蜂群表现和环境条件方面存在潜在的变化，但这种季节性在多年（2020-2022 年）和多个蜂群中保持一致。我们的分析发现 ACh/胆碱水平与温度、阳光、降水或有利于觅食的天数之间没有相关性，这表明可能涉及其他因素。这些发现强调了 ACh 水平的季节性波动及其对控制冬季蜜蜂发育的遗传程序的潜在影响。
