Measuring Caenorhabditis elegans Spatial Foraging and Food Intake Using Bioluminescent Bacteria
Measuring Caenorhabditis elegans Spatial Foraging and Food Intake Using Bioluminescent Bacteria
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DOI：
10.1534/genetics.119.302804
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发表时间：
2020-03-01
期刊：
影响因子：
3.3
通讯作者：
Brown, Andre E. X.
中科院分区：
文献类型：
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作者：
Ding, Siyu Serena;Romenskyy, Maksym;Brown, Andre E. X.
对于大多数动物来说，进食包括两种行为：觅食以找到食物块和一旦发现食物块就进食。线虫秀丽隐杆线虫是研究这两种行为遗传学的有用模型。然而，大多数测量蠕虫进食的方法都是量化觅食行为或食物摄入，而不是两者兼而有之。对荧光标记的细菌的消耗进行成像提供了关于消耗的分布和量的信息，但是即使在贴片耗尽之后，仍然存在突出的背景信号，这使得定量复杂化。在这里，我们使用了一种生物发光大肠杆菌菌株来定量C。elegans喂养由于光发射与活跃的新陈代谢紧密结合，只有活细菌才能生物发光，因此信号在摄入后就会丢失。我们使用N2参考蠕虫和突变体定量生物发光的损失，发现与荧光损失相比，信号背景比增加近100倍，背景更低。我们还定量喂养聚集突变蠕虫。我们发现，突变体群体首先从集群中清除细菌，然后集体觅食更多的食物;同样，在大规模的群体聚集期间，只有迁移前沿的蠕虫与细菌接触。这些结果证明了生物发光细菌在定量摄食和深入了解食物消费的空间模式方面的有用性。
For most animals, feeding includes two behaviors: foraging to find a food patch and food intake once a patch is found. The nematode Caenorhabditis elegans is a useful model for studying the genetics of both behaviors. However, most methods of measuring feeding in worms quantify either foraging behavior or food intake, but not both. Imaging the depletion of fluorescently labeled bacteria provides information on both the distribution and amount of consumption, but even after patch exhaustion a prominent background signal remains, which complicates quantification. Here, we used a bioluminescent Escherichia coli strain to quantify C. elegans feeding. With light emission tightly coupled to active metabolism, only living bacteria are capable of bioluminescence, so the signal is lost upon ingestion. We quantified the loss of bioluminescence using N2 reference worms and mutants, and found a nearly 100-fold increase in signal-to-background ratio and lower background compared to loss of fluorescence. We also quantified feeding using aggregating mutant worms. We found that groups of mutants first clear bacteria from within the cluster before foraging collectively for more food; similarly, during large population swarming, only worms at the migrating front are in contact with bacteria. These results demonstrate the usefulness of bioluminescent bacteria for quantifying feeding and generating insights into the spatial pattern of food consumption.