BIOCHEMICAL AND STRUCTURAL-ANALYSES OF THE EXTRACELLULAR-MATRIX FIBRILS OF MYXOCOCCUS-XANTHUS
BIOCHEMICAL AND STRUCTURAL-ANALYSES OF THE EXTRACELLULAR-MATRIX FIBRILS OF MYXOCOCCUS-XANTHUS
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DOI：
10.1128/jb.176.20.6295-6303.1994
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发表时间：
1994-10-01
影响因子：
3.2
通讯作者：
DWORKIN, M
中科院分区：
文献类型：
--
作者：
BEHMLANDER, RM;DWORKIN, M
产生大量细胞外物质是粘细菌的特征。该报告表明，黄色粘球菌中的这种物质是纤维状的，并描述了纤维的结构和化学成分。细胞外基质原纤维是 M. xanthus 细胞间粘附的介质。因此，原纤维在细胞间相互作用中发挥着重要作用，构成了该生物体社会和发育生活方式的基础。原纤维由蛋白质和碳水化合物组成，比例为 1.0:1.2。这两个部分合计占分离原纤维质量的 85% 以上，并且发现原纤维占固体表面上高密度生长的细胞干重的 10%。原纤维的多糖部分由五种不同的单糖组成：半乳糖、葡萄糖胺、葡萄糖、鼠李糖和木糖。葡萄糖胺是原纤维的单糖成分之一，也是已知的 M. xanthus 形态发生素，可将内聚力抑制到接近刚果红（内聚抑制的阳性对照）的水平。葡萄糖和木糖也抑制内聚力，但作用不如葡萄糖胺。对原纤维形态的分析、通过场发射扫描电子显微镜观察到的原纤维直径分布内的周期性以及对水合细胞上原纤维的观察强烈表明M. xanthus的细胞外基质确实排列为原纤维。此外，结果表明，原纤维被构建为具有相关蛋白质的碳水化合物结构。
It is characteristic of myxobacteria to produce large amounts of extracellular material. This report demonstrates that this material in Myxococcus xanthus is fibrillar and describes the structure and chemical composition of the fibrils. The extracellular matrix fibrils are the mediators of cell-cell cohesion in M. xanthus. As such, the fibrils play ad important role in the cell-cell interactions that form the basis for the Social and developmental lifestyle of this organism. The fibrils are composed of protein and carbohydrate in a 1.0:1.2 ratio. Combined, the two fractions accounted for greater than 85% of the mass of isolated fibrils, and the fibrils were found to compose up to 10% of the dry weight of cells grown at high density on a solid surface. The polysaccharide portion of the fibrils was shown to be composed of five different monosaccharides: galactose, glucosamine, glucose, rhamnose, and xylose. Glucosamine, one of the component monosaccharides of the fibrils and a known morphogen for M. xanthus, inhibited cohesion to a level near that of Congo red (the positive control for cohesion inhibition). Glucose and xylose also inhibited cohesion but less than did glucosamine. Analysis of the morphology of the fibrils, the periodicities within the distribution of fibril diameters observed by field emission scanning electron microscopy, and the observation of fibrils on hydrated cells strongly suggested that the extracellular matrix of M. xanthus was indeed arranged is fibrils. Furthermore, results suggested that the fibrils were constructed as carbohydrate structures with associated proteins.