Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA.
Department of Biological Sciences, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Fort Lauderdale FL, 33314, USA.
Microbes Infect. 2020 Sep;22(8):340-348. doi: 10.1016/j.micinf.2020.01.002. Epub 2020 Jan 31.
Despite being the first line of defense against infection, little is known about how host-pathogen interactions determine avoidance. Caenorhabditis elegans can become infected by chemoattractant-producing bacteria through ingestion. The worms can learn to associate these chemoattractants with harm through aversive learning. As a result, the worms will avoid the pathogen. Evolutionary constraints have likely shaped the attraction, intoxication and learning dynamics between bacteria and C. elegans, but these have not been explored. Using bacteria engineered to express an acylhomoserine lactone chemoattractant and a nematicidal protein, we explored how manipulating the amount of attractant produced by the bacteria affects learning and intoxication in mixed stage populations of C. elegans. We found that increasing the production rate of the chemoattractant increased the feeding rate in C. elegans, but decreased the time required for C. elegans to learn to avoid the chemoattractant. Learning generally coincided with a decreased feeding rate. We also observed that the percentage of intoxicated worms was maximized at intermediate production rates of the attractant. We propose that interactions between attractant driven feeding rate and aversive learning are likely responsible for this trend. Our results increase our understanding of behavioral avoidance in C. elegans and have implications in understanding host-pathogen dynamics that shape avoidance.
尽管是抵御感染的第一道防线，但人们对宿主-病原体相互作用如何决定回避知之甚少。秀丽隐杆线虫可以通过摄食来感染产生化学引诱剂的细菌。通过厌恶学习，这些线虫可以学会将这些化学引诱剂与伤害联系起来。因此，线虫会避免病原体。进化的限制可能已经塑造了细菌和 C. elegans 之间的吸引力、中毒和学习动态，但这些尚未得到探索。我们使用工程菌来表达酰基高丝氨酸内酯化学引诱剂和杀线虫蛋白，研究了改变细菌产生的引诱剂数量如何影响混合阶段 C. elegans 的学习和中毒。我们发现，增加化学引诱剂的产生速率会增加线虫的摄食率，但会降低线虫学会回避化学引诱剂所需的时间。学习通常与摄食率的降低同时发生。我们还观察到，在引诱剂产生速率的中间水平，中毒线虫的百分比达到最大值。我们提出，引诱剂驱动的摄食率和厌恶学习之间的相互作用可能是造成这种趋势的原因。我们的研究结果增加了我们对 C. elegans 中行为回避的理解，并对理解塑造回避的宿主-病原体动态具有重要意义。
