Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Centro de Ciências de Saúde, Bloco I, 21941-902 Rio de Janeiro, Brazil.
Micron. 2010 Jul;41(5):507-17. doi: 10.1016/j.micron.2010.01.009. Epub 2010 Feb 11.
The main criterion to classify a microorganism as belonging to the genus Beggiatoa is its morphology. All multicellular, colorless, gliding bacterial filaments containing sulfur globules described so far belong to this genus. At the ultrastructural level, they show also a very complex cell envelope structure. Here we describe uncultured vacuolated and non-vacuolated bacteria from two different environments showing all characteristics necessary to assign a bacterium to the genus Beggiatoa. We also intended to investigate whether narrow and vacuolate Beggiatoa do differ morphologically as much as they do phylogenetically. Both large, vacuolated trichomes and narrow filaments devoid of vacuoles were observed. We confirmed the identity of the narrow filaments by 16S rRNA phylogenetic analysis. The diameters of the trichomes ranged from 2.4 to 34 microm, and their lengths ranged from 10 microm to over 30 mm. Narrow trichomes moved by gliding at 3.0 microm/s; large filaments moved at 1.5 microm/s. Periplasmic sulfur inclusions were observed in both types of filaments, whereas phosphorus-rich bodies were found only in narrow trichomes. On the other hand, nitrate vacuoles were observed only in large trichomes. Ultra-thin section transmission electron microscopy showed differences between the cell ultrastructure of narrow (non-vacuolated) and large (vacuolated) Beggiatoa. We observed that cell envelopes from narrow Beggiatoa consist of five layers, whereas cell envelopes from large trichomes contain four layers.
将微生物归类为 Beggiatoa 属的主要标准是其形态。迄今为止，所有描述的多细胞、无色、滑行的含硫球杆菌都属于这个属。在超微结构水平上，它们还显示出非常复杂的细胞膜结构。在这里，我们描述了来自两个不同环境的未培养的空泡状和非空泡状细菌，它们具有将细菌归为 Beggiatoa 属的所有必要特征。我们还旨在研究狭窄和空泡状的 Beggiatoa 在形态上是否与系统发育上有很大的不同。我们观察到了大的空泡状的发状毛和没有空泡的狭窄丝状菌。我们通过 16S rRNA 系统发育分析证实了狭窄丝状菌的身份。发状毛的直径范围从 2.4 到 34 微米，长度从 10 微米到 30 毫米以上。狭窄的发状毛以 3.0 微米/秒的速度滑行移动；大的丝状菌以 1.5 微米/秒的速度移动。在两种丝状菌中都观察到了周质硫内含物，而富磷体仅存在于狭窄的发状毛中。另一方面，只有在大的发状毛中才观察到硝酸盐液泡。超薄切片透射电子显微镜显示了狭窄（非空泡状）和大（空泡状）Beggiatoa 的细胞超微结构之间的差异。我们观察到，狭窄 Beggiatoa 的细胞膜由五层组成，而大的发状毛的细胞膜由四层组成。
