An Early-Branching Microbialite Cyanobacterium Forms Intracellular Carbonates
An Early-Branching Microbialite Cyanobacterium Forms Intracellular Carbonates
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DOI：
10.1126/science.1216171
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发表时间：
2012-04-27
期刊：
影响因子：
56.9
通讯作者：
Lopez-Garcia, Purificacion
中科院分区：
文献类型：
--
作者：
Couradeau, Estelle;Benzerara, Karim;Lopez-Garcia, Purificacion
蓝藻影响地球上主要的地球化学循环(碳、氮和氧)已有数十亿年之久。特别是，它们在碳酸钙的形成(即钙化)中发挥了重要作用，而碳酸钙被认为是一种细胞外过程。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，它在细胞内形成了平均直径约270纳米的无定形钙-镁-锶-碳酸钡包裹体，揭示了一条未知的钙化途径。系统发育分析将该蓝藻归入深度分化的球藻纲。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。这一发现扩大了能够形成无定形碳酸钙的生物体的多样性。
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.