Aerotaxis in Desulfovibrio
Aerotaxis in Desulfovibrio
复制标题
DOI：
10.1046/j.1462-2920.1999.00057.x
复制
发表时间：
1999-12-01
影响因子：
5.1
通讯作者：
Cypionka, H
中科院分区：
文献类型：
--
作者：
Eschemann, A;Kühl, M;Cypionka, H
使用毛细管载玻片、显微镜和氧气微传感器研究了两种硫酸盐还原菌的趋气性，即淡水菌株 Desulfovibrio desulfuricans CSN (DSM 9104) 和海洋菌株 Desulfovibrio oxyclinae N13 (DSM 11498)。细菌在 O-2 气泡周围的氧扩散梯度中形成环形带，将其放入毛细管微玻片中的缺氧无硫酸盐细胞悬浮液中。通过扩散导致的含氧量的径向扩张被有氧呼吸停止。带是由避免 O-2 气泡附近高 O-2 水平的细胞以及从周围缺氧区进入的细胞形成的。在带的内边缘，发现 O-2 水平高达 20% 空气饱和度 (50 μM O-2)，而外边缘始终与缺氧界面重合。带内边缘的环直径和 O-2 浓度取决于细胞密度和悬浮液中使用的菌株。在没有电子供体（5 mM 乳酸）或使用 N-2 气泡时，不会发生带形成。两种菌株均具有高度运动能力，向前运行时的速度约为 32 μ m s(-1)，向后运行时的速度约为 7 μ m s(-1)。在带内，细胞以直径约20μm的圆圈移动，而带外的细胞表现出更直的或仅稍微弯曲的痕迹。结论是，在存在足够电子供体和高细胞密度的情况下，脱硫弧菌的高速率呼吸能力以及正向和负向航空反应提供了从栖息地去除 O-2 的有效策略。
Aerotaxis of two sulphate-reducing bacteria, the freshwater strain Desulfovibrio desulfuricans CSN (DSM 9104) and the marine strain Desulfovibrio oxyclinae N13 (DSM 11498), was studied using capillary microslides, microscopy and oxygen microsensors. The bacteria formed ring-shaped bands in oxygen diffusion gradients surrounding O-2 bubbles, which were placed into anoxic sulphate-free cell suspensions in capillary microslides. The radial expansion of the oxic volume by diffusion was stopped by aerobic respiration. Bands were formed by cells avoiding high O-2 levels near the O-2 bubble, as well as by cells entering from the surrounding anoxic zone. At the inner edge of the bands, O-2 levels of up to 20% air saturation (50 mu M O-2) were found, while the outer edge always coincided with the oxic-anoxic interface. Ring diameters and O-2 concentrations at the inner edge of the band depended on the cell density and the strain used in the suspension. Band formation did not occur in the absence of an electron donor (5 mM lactate) or when N-2 gas bubbles were used. Both strains were highly motile with velocities of approximate to 32 mu m s(-1) during forward runs, and 7 mu m s(-1) during backward runs respectively. Within the bands, cells moved in circles of about 20 mu m diameter, while cells outside the band exhibited straighter or only slightly bent traces. It is concluded that the capacity of respiration at high rates and the positive and negative aerotactical responses of Desulfovibrio provide an efficient strategy for removing O-2 from the habitat in situations where sufficient electron donors and high cell densities are present.