POLYANION-MEDIATED MINERALIZATION - ASSEMBLY AND REORGANIZATION OF ACIDIC POLYSACCHARIDES IN THE GOLGI SYSTEM OF A COCCOLITHOPHORID ALGA DURING MINERAL DEPOSITION
POLYANION-MEDIATED MINERALIZATION - ASSEMBLY AND REORGANIZATION OF ACIDIC POLYSACCHARIDES IN THE GOLGI SYSTEM OF A COCCOLITHOPHORID ALGA DURING MINERAL DEPOSITION
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DOI：
10.1007/bf01378985
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发表时间：
1994-01-01
期刊：
影响因子：
2.9
通讯作者：
MARSH, ME
中科院分区：
文献类型：
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作者：
MARSH, ME
免疫定位的两个高度酸性多糖（PS-1和PS-2）在钙化的Pleurochrysiscarterae描述整个矿化过程中，从晶体成核通过停止晶体生长。这种单细胞球石藻是一种有用的矿化模型，因为它在均匀的细胞培养中产生钙化的鳞片，称为球石。PS-1和PS-2定位于成熟球蚴的晶衣和电子致密的高尔基体颗粒中。聚阴离子在内侧高尔基池中合成，并与钙离子共聚集成离散的25 nm颗粒。充满颗粒的小泡从池边缘萌芽，并与形成球石的球囊融合，球囊包含有机的椭圆形鳞片，形成未来球石的基部。这些颗粒在矿物沉积开始之前就定位在基底上，并且在晶体（CaCO 3）成核和生长的整个期间存在于颗石球囊中。在颗石形成的最后阶段，颗粒消失，成熟的晶体获得含有PS-1和PS-2多糖的无定形涂层，这些多糖在颗石从细胞中挤出后保留在矿物相中。多阴离子介导的矿化的假设机制进行审查，并解决其相关性的钙化球石。
Immunolocalization of two highly acidic polysaccharides (PS-1 and PS-2) in a calcifying alga Pleurochrysis carterae is described throughout the mineralization process, from before crystal nucleation through the cessation of crystal growth. This unicellular coccolithophorid alga is a useful model for mineralization because it produces calcified scales known as coccoliths in homogeneous cell culture. PS-1 and PS-2 were localized in the crystal coats of mature coccoliths and in electron dense Golgi particles. The polyanions are synthesized in medial Golgi cisternae and co-aggregate with calcium ions into discrete 25 nm particles. Particle-laden vesicles bud from cisternal margins and fuse with a coccolith-forming saccule containing an organic oval-shaped scale which forms the base of the future coccolith. The particles are localized on the base before the onset of mineral deposition and are present in the coccolith saccule throughout the period of crystal (CaCO3) nucleation and growth. During the final phase of coccolith formation, the particles disappear, and the mature crystals acquire an amorphous coat containing PS-1 and PS-2 polysaccharides which remain with the mineral phase after the coccoliths are extruded from the cell. Postulated mechanisms of polyanion-mediated mineralization are reviewed and their relevance to the calcification of coccoliths is addressed.