海に住む単細胞性石灰化生物 有孔虫の殻形成

抄録

  Foraminifers are unicellular eukaryotes that primarily inhabit the ocean. Calcareous foraminifers have been forming calcium carbonate shells. The calcareous shells are used as environmental indicators as a geologic record because they are stored in sediments for an extended period. However, the necessary process of shell formation of foraminifera was not well studied. Therefore, we have investigated how calcium and carbonate ions uptake by the biological process at the site of calcification. We also show how the microscopic structure of the calcification site where the shell formation process proceeds. In our study, after optically observing the shell formation process, fluorescence imaging was performed to record the environment inside and outside the calcification site. Besides, the electron microscopy clarified that organic structures define the detailed calcareous structures. These relationships had been almost ignored in this couple of decades. By obtaining samples of various stages during shell formation through laboratory culture experiments, we were able to study the mechanism of chamber formation.