Aerotactic response of Azospirillum brasilense
Aerotactic response of Azospirillum brasilense
复制标题
巴西固氮螺菌的趋气反应
DOI：
10.1128/jb.152.2.643-649.1982
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发表时间：
1982
影响因子：
3.2
通讯作者：
Y. Henis
中科院分区：
文献类型：
--
作者：
R. Barak;I. Nur;Y. Okon;Y. Henis
来自以色列的五种固氮螺菌菌株和两种固氮螺菌属物种，通过在毛细管中形成气动带并主动向溶解氧较低的特定区域移动，对自行创造和预先形成的氧气梯度做出反应。增加含有磷酸盐缓冲液的毛细管中的氧浓度会增加所吸引的细菌数量并降低带速度。高浓度的 O2 和 H2O2 暂时排斥细菌，导致毛细血管口周围形成细菌弧。在厌氧条件下没有条带形成，尽管细菌仍保持高度活动性。固氮螺菌属的趋气性不需要外源能源。向毛细管中添加可氧化底物会稍微增强趋气性，这可能是通过加速 O2 消耗来实现的。气动带的形成受pH、细菌浓度和年龄、培养时间和呼吸抑制剂的影响，但不受生长培养基中缺乏结合氮的影响。有人提出，趋气性在固氮螺菌属的能力中发挥着作用。达到适合N2固定的环境。
Five strains of Azospirillum brasilense and two of Azospirillum spp., from Israel, responded to self-created and preformed oxygen gradients by forming aerotactic bands in capillary tubes and actively moving toward a specific zone with low dissolved oxygen. Increasing the oxygen concentration in capillaries containing phosphate buffer increased the number of attracted bacteria and decreased band velocity. High O2 concentrations and H2O2 temporarily repulsed the bacteria, causing the formation of a bacterial arc around the capillary mouth. There was no band formation under anaerobic conditions, although the bacteria remained highly motile. Exogenous energy sources were unnecessary for aerotaxis in Azospirillum spp. The addition of oxidizable substrates to the capillary slightly enhanced aerotaxis, possibly by accelerating O2 consumption. Aerotactic band formation was affected by pH, bacterial concentration and age, incubation time, and respiratory inhibitors, but not by the lack of combined nitrogen in the growth medium. It is proposed that aerotaxis plays a role in the capacity of Azospirillum spp. to reach an environment suitable for N2 fixation.