Shen Ping
Cold Spring Harb Protoc. 2012 Aug 1;2012(8):pdb.prot069336. doi: 10.1101/pdb.prot069336.
The food responses of Drosophila larvae offer an excellent opportunity to study the genetic and neural regulation of feeding behavior. Compared with fed larvae, hungry larvae are more likely to display aggressive foraging, rapid food intake, compensatory feeding, and stress-resistant food procurement. Omnivores, including humans, tend to avoid noxious or unfamiliar food. Fly larvae avoid bitter substances such as quinine. As an increasing amount of quinine is added to an otherwise palatable liquid medium containing sugar and inactivated yeast, larvae become less likely to consume the tainted food. Larval feeding activity is assayed by scoring the percentage of larvae containing dyed food in a large portion of the midgut. Defensive foraging behavior can be modulated by physiological need and food deprivation significantly increases larval tolerance to quinine. Therefore, the larval response to quinine food and its regulation by hunger provides a useful paradigm for elucidating the genetic and neural regulation of food choice that favors short-term survival. The test described here is designed for quantitative assessment of the motivation of individual larvae to ingest quinine-adulterated food under different energy states. The test is applicable to routine functional testing and larger-scale screening of genetic mutations and biologics that might affect food consumption.
果蝇幼虫的食物反应为研究进食行为的遗传和神经调节提供了绝佳机会。与进食的幼虫相比，饥饿的幼虫更有可能表现出攻击性觅食、快速进食、补偿性进食和抗应激食物获取行为。包括人类在内的杂食动物往往会避开有害或不熟悉的食物。果蝇幼虫会避开苦味物质，如奎宁。当向含有糖和灭活酵母的原本可口的液体培养基中添加越来越多的奎宁时，幼虫食用受污染食物的可能性就会降低。通过对大部分中肠中含有染色食物的幼虫百分比进行评分来测定幼虫的进食活动。防御性觅食行为可受生理需求调节，食物剥夺会显著提高幼虫对奎宁的耐受性。因此，幼虫对奎宁食物的反应及其受饥饿的调节为阐明有利于短期生存的食物选择的遗传和神经调节提供了一个有用的范例。此处描述的试验旨在定量评估处于不同能量状态下的单个幼虫摄取掺有奎宁食物的动机。该试验适用于对可能影响食物消耗的基因突变和生物制剂进行常规功能测试和大规模筛选。
