Laboratoire de Chimie Bactérienne, Université de la Méditerranée Aix-Marseille II, France.
Environ Microbiol. 2009 Jul;11(7):1646-57. doi: 10.1111/j.1462-2920.2009.01887.x. Epub 2009 Feb 12.
The widespread magnetotactic bacteria have the peculiar capacity of navigation along the geomagnetic field. Despite their ubiquitous distribution, only few axenic cultures have been obtained worldwide. In this study, we reported the first axenic culture of magnetotactic bacteria isolated from the Mediterranean Sea. This magneto-ovoid strain MO-1 grew in chemically defined O(2) gradient minimal media at the oxic-anoxic transition zone. It is phylogenetically related to Magnetococcus sp. MC-1 but might represent a novel genus of Proteobacteria. Pulsed-field gel electrophoresis analysis indicated that the genome size of the MO-1 strain is 5 ± 0.5 Mb, with four rRNA operons. Each cell synthesizes about 17 magnetosomes within a single chain, two phosphorous-oxygen-rich globules and one to seven lipid storage granules. The magnetosomes chain seems to divide in the centre during cell division giving rise to two daughter cells with an approximately equal number of magnetosomes. The MO-1 cell possesses two bundles of seven individual flagella that were enveloped in a unique sheath. They swam towards the north pole with a velocity up to 300 μm per second with frequent change from right-hand to left-hand helical trajectory. Using a magneto-spectrophotometry assay we showed that MO-1 flagella were powered by both proton-motive force and sodium ion gradient, which is a rare feature among bacteria.
具有沿地磁场导航特殊能力的广布磁细菌。尽管它们无处不在，但在全球范围内仅获得了少数无菌培养物。在这项研究中，我们报告了从地中海分离的磁细菌的第一个无菌培养物。这种磁卵形菌株 MO-1 在有氧-缺氧过渡区的化学定义 O(2)梯度最小培养基中生长。它在系统发育上与 Magnetococcus sp. MC-1 有关，但可能代表了一种新的变形菌门属。脉冲场凝胶电泳分析表明，MO-1 菌株的基因组大小为 5 ± 0.5 Mb，有四个 rRNA 操纵子。每个细胞在单个链内合成约 17 个磁小体、两个磷氧丰富的球体和一个到七个脂质储存颗粒。磁小体链似乎在细胞分裂过程中在中心分裂，产生两个具有大致相等数量的磁小体的子细胞。MO-1 细胞具有两束由七个单独的鞭毛组成的鞭毛，这些鞭毛被独特的鞘包裹。它们以高达 300 μm/s 的速度向北极游动，并经常从右手螺旋轨迹变为左手螺旋轨迹。使用磁分光光度测定法，我们表明 MO-1 鞭毛由质子动力势和钠离子梯度驱动，这在细菌中是罕见的特征。
