Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan.
Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minami, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Sci Adv. 2020 Apr 8;6(15):eaaz0882. doi: 10.1126/sciadv.aaz0882. eCollection 2020 Apr.
Planarians exhibit traits of cephalization but are unique among bilaterians in that they ingest food by means of goal-directed movements of a trunk-positioned pharynx, following protrusion of the pharynx out of the body, raising the question of how planarians control such a complex set of body movements for achieving robust feeding. Here, we use the freshwater planarian to show that an isolated pharynx amputated from the planarian body self-directedly executes its entire sequence of feeding functions: food sensing, approach, decisions about ingestion, and intake. Gene-specific silencing experiments by RNA interference demonstrated that the pharyngeal nervous system (PhNS) is required not only for feeding functions of the pharynx itself but also for food-localization movements of individual animals, presumably via communication with the brain. These findings reveal an unexpected central role of the PhNS in the linkage between unique morphological phenotypes and feeding behavior in planarians.
涡虫表现出脑化特征，但在两侧对称动物中它们是独一无二的，因为它们通过位于躯干位置的咽部的定向运动来摄取食物，在咽部从身体中伸出后，提高了这样一个复杂的身体运动如何控制用于实现强壮的喂养问题。在这里，我们使用淡水涡虫来表明，从涡虫身体上截断的孤立咽部会自我指导地执行其整个进食功能序列：食物感应、接近、关于摄取的决策和摄取。通过 RNA 干扰的基因特异性沉默实验表明，咽部神经系统 (PhNS) 不仅是咽部自身进食功能所必需的，而且对于个体动物的食物定位运动也是必需的，可能是通过与大脑的通信。这些发现揭示了 PhNS 在独特形态表型和涡虫进食行为之间的联系中的意外核心作用。
