An ultrastructural study of iron and manganese deposition associated with extracellular polymers of pedomicrobium-like budding bacteria
An ultrastructural study of iron and manganese deposition associated with extracellular polymers of pedomicrobium-like budding bacteria
复制标题
与类足微生物出芽细菌胞外聚合物相关的铁和锰沉积的超微结构研究
作者：
W. Ghiorse;P. Hirsch
描述了两种类Pedomicrobium 出芽细菌的形态特征。在菌株 868 上经常观察到结构化表面层。在两个菌株上都发现了钌红和阿尔新蓝染色聚合物。当任一菌株在铁或锰存在下生长时，相应的氧化物会在其表面积累。在薄片中，氧化铁表现为细线、颗粒阵列或致密涂层，具体取决于铁的来源。锰氧化物呈分支丝状或卷曲带状。两种金属氧化物都被钌红染色。提取氧化物后进行钌红染色，结果显示先前沉积在细胞上的聚阴离子聚合物与金属相关。用戊二醛、HgCl2 或加热处理培养物，抑制了锰沉积，但没有抑制铁沉积，表明铁氧化物是通过被动的非生物过程积累的。锰氧化物显然是在生物锰氧化因子的控制下积累的。在细胞悬浮液中观察到的锰沉积的不完全抑制表明，如果氧化因子是一种酶，则它异常稳定。基于这些结果，提出了与细胞外聚合物相关的铁和锰沉积的可能机制。
Morphological characteristics of two Pedomicrobium-like budding bacteria are described. A structured surface layer was regularly observed on strain 868. Ruthenium red- and Alcian blue-staining polymers were found on both strains.When either strain was grown in the presence of iron or manganese, the corresponding oxides accumulated on their surfaces. In thin sections iron oxides appeared as fine threads, arrays of particles or dense coatings, depending on the source of iron. Manganese oxides appeared as branching filaments or convoluted ribbons. Both metal oxides stained with ruthenium red. Extraction of the oxides followed by ruthenium red staining revealed that polyanionic polymers previously deposited on the cells were associated with the metals.Treatment of cultures with glutaraldehyde, HgCl2, or heat, inhibited manganese but not iron deposition, suggesting that iron oxides accumulated by passive, non-biological processes. Manganese oxides apparently accumulated under control of a biological manganese-oxidizing factor. Incomplete inhibition of manganese deposition observed in cell suspensions suggested that, if the oxidizing factor was an enzyme, it was unusually stable.Based on these results, possible mechanisms of iron and manganese deposition in association with extracellular polymers are suggested.