Division of Membrane Biology, Biosignal Research Center, Graduate School of Medicine, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
Department of Biological Sciences, Faculty of Science and Technology, Kochi University, 2-5-1 Akebono, Kochi 780-8520, Japan.
Eur J Protistol. 2023 Apr;88:125971. doi: 10.1016/j.ejop.2023.125971. Epub 2023 Mar 8.
The centrohelid heliozoan Raphidocystis contractilis has hundreds of small scales on the surface of the cell body. To understand the biological functions of the scales, comparative examinations were conducted between wild-type and scale-deficient strains that has naturally lost scales after long-term cultivation. The scale-deficient strain exhibited decreased adhesion to the substratum and had a lower sedimentation rate in water than the wild-type strain, suggesting that the scale may have the ability to attach quickly and strongly to the substratum. Percoll density gradient centrifugation showed that the scale-deficient strain had a lower density than that of the wild-type strain. In the wild-type strain, more scaled cells were observed in the higher specific gravity fractions. During the long-term culture of cells, only the cells suspended in the upper area of the flask were transferred to fresh medium. By repeating this procedure, we may have selected only cells that did not possess normal scales. In the natural environment, centrohelid heliozoans are easily flushed away if they cannot adhere strongly to the bottom. These results suggest that they use scales to ensure effective adhesion to the substratum.
细胞表面有数百个小鳞片的中心体 Heliozoan Raphidocystis contractilis。为了了解鳞片的生物学功能，对经过长期培养后自然失去鳞片的野生型和鳞片缺陷型菌株进行了比较研究。与野生型菌株相比，鳞片缺陷型菌株对基质的粘附能力降低，在水中的沉降率也较低，这表明鳞片可能具有快速、牢固地附着在基质上的能力。Percoll 密度梯度离心显示，鳞片缺陷型菌株的密度低于野生型菌株。在野生型菌株中，观察到更多带有鳞片的细胞存在于比重较高的部分。在细胞的长期培养过程中，只将悬浮在培养瓶上部区域的细胞转移到新鲜的培养基中。通过重复这个过程，我们可能只选择了那些不具有正常鳞片的细胞。在自然环境中，如果中心体 Heliozoan 不能牢固地附着在底部，它们很容易被冲走。这些结果表明，它们使用鳞片来确保与基质的有效粘附。
