Pakhnevich Alexey, Nikolayev Dmitry, Lychagina Tatiana
Borissiak Paleontological Institute, Russian Academy of Sciences, 117647 Moscow, Russia.
Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
Biology (Basel). 2023 Nov 27;12(12):1472. doi: 10.3390/biology12121472.
Unicellular protozoa form calcium carbonate tests. It is important to understand the features and mechanisms of its formation. This may shed light on the processes of shell formation in metazoans. One of the most important characteristics of the Protozoa carbonate test is the degree of crystal ordering that can be described by crystallographic texture. The crystallographic texture data of calcite in the foraminifera (Deshayes) test from the Eocene deposits (Cenozoic, Paleogene) of the Crimea Peninsula are obtained using X-ray diffraction. A very strict orientation of the crystals is revealed. The calcite texture sharpness is several times greater than in the shells of the bivalve mollusk (Linnaeus), measured by the same method. It also exceeds the crystallographic texture and sharpness of the same mineral in the shells of the bivalves of (Lamarck), studied by neutron diffraction. It is concluded that a high level of control during test formation is already characteristic of protozoa. Studying the processes involved in the formation of a very sharp crystallographic texture can become an important direction for creating nature-like materials with desired properties.
单细胞原生动物形成碳酸钙外壳。了解其形成的特征和机制很重要。这可能会揭示后生动物贝壳形成的过程。原生动物碳酸盐外壳最重要的特征之一是晶体有序程度，这可以用晶体结构来描述。利用X射线衍射获得了来自克里米亚半岛始新世沉积物（新生代，古近纪）的有孔虫（德夏耶斯）外壳中方解石的晶体结构数据。结果显示晶体具有非常严格的取向。用相同方法测量，方解石的晶体结构清晰度比双壳贝类软体动物（林奈）的贝壳高出几倍。它也超过了通过中子衍射研究的（拉马克）双壳贝类贝壳中相同矿物的晶体结构和清晰度。得出的结论是，在外壳形成过程中高水平的控制已经是原生动物的特征。研究形成非常清晰的晶体结构所涉及的过程可能会成为制造具有所需特性的仿生材料的一个重要方向。
