2023-11-22 カリフォルニア工科大学(Caltech)
◆Caltechの研究者は、Caulerpaが光の昼夜サイクルに同期した波のようなクロロプラストを放出し、これによって成長している可能性があると示唆しています。これにより、Caulerpaは異なる昼夜の長さに適応でき、光が植物に成長の合図を送り、休息の時間を教えている可能性があります。
<関連情報>
- https://www.caltech.edu/about/news/growth-of-a-giant-single-cell-is-intertwined-with-daily-self-rhythms
- https://www.nature.com/articles/s41467-023-41813-6
巨大な単細胞緑藻における巨視的波動、生物時計、そして光による形態形成 Macroscopic waves, biological clocks and morphogenesis driven by light in a giant unicellular green alga
Eldad Afik,Toni J. B. Liu & Elliot M. Meyerowitz
Nature Communications Published:04 October 2023
DOI:https://doi.org/10.1038/s41467-023-41813-6
Abstract
A hallmark of self-organisation in living systems is their capacity to stabilise their own dynamics, often appearing to anticipate and act upon potential outcomes. Caulerpa brachypus is a marine green alga consisting of differentiated organs resembling leaves, stems and roots. While an individual can exceed a metre in size, it is a single multinucleated giant cell. Thus Caulerpa presents the mystery of morphogenesis on macroscopic scales in the absence of cellularization. The experiments reported here reveal self-organised waves of greenness — chloroplasts — that propagate throughout the alga in anticipation of the day-night light cycle. Using dynamical systems analysis we show that these waves are coupled to a self-sustained oscillator, and demonstrate their entrainment to light. Under constant conditions light intensity affects the natural period and drives transition to temporal disorder. Moreover, we find distinct morphologies depending on light temporal patterns, suggesting waves of chlorophyll could link biological oscillators to metabolism and morphogenesis in this giant single-celled organism.
