Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.
Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.
复制标题
DOI：
10.1111/j.1574-6941.2011.01099.x
复制
发表时间：
2011-07-01
影响因子：
4.2
通讯作者：
Jorgensen, Bo Barker
中科院分区：
文献类型：
--
作者：
Dunker, Rita;Roy, Hans;Jorgensen, Bo Barker
大型硫磺细菌Beggiatoa spp.依靠氧气或硝酸盐氧化硫化物为生，但避免高浓度的硫化物和氧气。作为滑行的细丝，它们依靠滑行方向的反转来找到它们喜欢的环境--氧-硫化物界面。我们观察了单丝在透明琼脂介质中的趋化模式，并对它们的逆转和逆转之间的滑动距离进行了评分。首选微环境中的细丝在反转之间滑动的距离比它们自己的长度要短，这些反转将它们固定在它们作为微生物垫子的位置。在垫子上方的氧化区或在垫子下面的硫化、缺氧区中的细丝在反转之间滑动的距离大于细丝长度。这种反转行为导致了细丝的扩散状展开。根据我们的观测结果，建立了这种滑行细丝的数值模型。该模型被应用于沉积物中无氧无硫化物区域的虚拟细丝，这是Beggiatoa在自然环境中的主要栖息地。该模型预测了虚拟细丝在亚氧区的长时间停留，并解释了为什么Beggiatoa在内部液泡中积累了高浓度的硝酸盐作为氧的替代电子受体。
The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen-sulfide interface. We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment glided distances shorter than their own length between reversals that anchored them in their position as a microbial mat. Filaments in the oxic region above the mat or in the sulfidic, anoxic region below the mat glided distances longer than the filament length between reversals. This reversal behavior resulted in a diffusion-like spreading of the filaments. A numerical model of such gliding filaments was constructed based on our observations. The model was applied to virtual filaments in the oxygen- and sulfide-free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen.