Institut de Minéralogie et de Physique de la Matière Condensée, CNRS UMR 7590, Université Pierre et Marie Curie, Paris, France.
Science. 2012 Apr 27;336(6080):459-62. doi: 10.1126/science.1216171.
Cyanobacteria have affected major geochemical cycles (carbon, nitrogen, and oxygen) on Earth for billions of years. In particular, they have played a major role in the formation of calcium carbonates (i.e., calcification), which has been considered to be an extracellular process. We identified a cyanobacterium in modern microbialites in Lake Alchichica (Mexico) that forms intracellular amorphous calcium-magnesium-strontium-barium carbonate inclusions about 270 nanometers in average diameter, revealing an unexplored pathway for calcification. Phylogenetic analyses place this cyanobacterium within the deeply divergent order Gloeobacterales. The chemical composition and structure of the intracellular precipitates suggest some level of cellular control on the biomineralization process. This discovery expands the diversity of organisms capable of forming amorphous calcium carbonates.
蓝藻在地球上影响了主要的地球化学循环（碳、氮和氧）数十亿年。特别是，它们在碳酸钙的形成（即钙化）中发挥了主要作用，这被认为是一个细胞外过程。我们在墨西哥阿尔奇奇卡湖的现代微生物岩中发现了一种蓝藻，它在细胞内形成平均直径约 270 纳米的无定形钙镁锶钡碳酸盐包合物，揭示了一种未被探索的钙化途径。系统发育分析将这种蓝藻置于深分歧的绿菌目内。细胞内沉淀物的化学成分和结构表明，细胞对生物矿化过程有一定程度的控制。这一发现扩展了能够形成无定形碳酸钙的生物体的多样性。
