Ethological dynamics in diorama environments

Testate amoebae, which lack eyes, hands, or brains, construct an egg-shaped shell using pseudopodia outside the cell in a space without a template, but the principle behind this process is not known. In this study, two types of testate amoebae are placed in a diorama environment and observed to elucidate the principles of their shell construction behavior. We will use light and transmission electron microscopy to analyze the behavior of the testate amoebae Paulinella, which produce the shell parts within the cell, after the shell construction is interfered or the shell parts are removed using optical tweezers or micro-manipulators. Then we will discuss the coordination between the shell construction and the cell cycle and the flexibility of the process of the shell construction. We will also observe the shell construction behavior of the testate amoebae Diffulugia, which collect their shell parts from the habitat environment. To clarify the selection factors of their shell parts, we will start establishing cultures because there are no available cultures of Diffulugia. Using the established culture, we will analyze their behavior using time-lapse video recording and transmission electron microscopy.