Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country, P. O. Box 644, E-48080 Bilbao, Spain.
J Eukaryot Microbiol. 2009 Mar-Apr;56(2):188-93. doi: 10.1111/j.1550-7408.2008.00387.x.
To enhance our understanding of the factors affecting feeding selectivity of bacterivorous protists in aquatic systems, we examined the preference responses of the freshwater ciliate Uronema nigricans towards three bacterial prey taxa, Pseudomonas luteola, Serratia rubidaea, and Aeromonas hydrophila. Potential factors influencing the predator-prey contact rate included the previous feeding history of the ciliate and physiological state of bacteria. Preference indexes were obtained from multiple-choice mazes in which ciliates moved preferentially towards alternative bacteria or the prey species on which they had been feeding. Uronema nigricans showed differential attraction towards the offered prey types, and these preferences varied as a function of the ciliate feeding history: U. nigricans growing on P. luteola showed lower preference responses towards the offered bacteria than U. nigricans growing on S. rubidaea. The bacteria in stationary phase elicited a higher degree of attraction than bacteria in exponential phase, probably due to a higher concentration of carbohydrates in the former. Therefore, this protist will preferentially swim towards bacteria in stationary growth phase, although the degree of this response will be affected by the recent feeding history of the ciliate.
为了增强我们对影响水生系统中噬菌原生动物摄食选择性因素的理解，我们研究了淡水纤毛虫 Uronema nigricans 对三种细菌猎物类群（Pseudomonas luteola、Serratia rubidaea 和 Aeromonas hydrophila）的偏好反应。影响捕食者-猎物接触率的潜在因素包括纤毛虫的先前摄食历史和细菌的生理状态。通过选择迷宫获得了偏好指数，纤毛虫在其中更倾向于选择替代细菌或它们正在摄食的猎物物种。Uronema nigricans 对提供的猎物类型表现出不同的吸引力，并且这些偏好随着纤毛虫的摄食历史而变化：在 P. luteola 上生长的 U. nigricans 对提供的细菌的偏好反应低于在 S. rubidaea 上生长的 U. nigricans。静止期细菌比指数生长期细菌更能引起强烈的吸引力，这可能是由于前者的碳水化合物浓度较高。因此，尽管这种反应的程度会受到纤毛虫最近的摄食历史的影响，但这种原生动物将优先向静止生长阶段的细菌游动。
