Chemotaxis of a cyanobacterium on concentration gradients of carbon dioxide, bicarbonate and oxygen
Chemotaxis of a cyanobacterium on concentration gradients of carbon dioxide, bicarbonate and oxygen
复制标题
蓝藻对二氧化碳、碳酸氢盐和氧气浓度梯度的趋化性
DOI：
10.1099/00221287-131-10-2643
复制
发表时间：
1985
期刊：
影响因子：
1.5
通讯作者：
A. Walsby
中科院分区：
文献类型：
--
作者：
G. Malin;A. Walsby
摘要：悬浮在培养皿中软琼脂中的振荡菌的毛状体显示出主动移动，远离通过在表面放置玻璃盖来阻止气体交换的区域。这种清除反应只发生在光照下，并且与琼脂层中形成的无机碳的梯度有关。在玻璃盖下面的中心区域积聚的深色毛状体中孵育的盘子中，但无法确定引起这种反应的物质。在软琼脂中悬浮的蓝藻草坪内建立了扩散物质的梯度，并证明了振荡藻的毛向CO2移动。光依赖性趋化反应中的HCO3和O2。这些物质在黑暗中没有趋化作用。2 h后检测到趋化反应，但在8 h后变得越来越明显。由于毛状体从空气中向CO2源移动，CO2的趋化活性浓度大于大气浓度。利用扩散系数计算了振荡藻毛在CO2分压为0.02 bar（相当于0.83 mM）时的累积。以O2为化学引诱剂时，该值为0.35 bar （14.56 mM）。这些结果与无机碳和氧在蓝藻代谢中的作用进行了讨论，并得出趋化行为可能在沉积物环境光带内的运动中起重要作用。
Summary: Trichomes of an Oscillatoria sp. suspended in soft agar in Petri dishes showed active movement away from areas where gaseous exchange had been prevented by placing glass coverslips on the surface. This clearance response occurred only in the light and it was related to gradients of inorganic carbon that formed in the agar layer. In plates incubated in the dark trichomes accumulated in the central areas below glass coverslips but the substance eliciting this response could not be identified. Gradients of diffusible substances were established within lawns of cyanobacteria suspended in soft agar and it was demonstrated that trichomes of Oscillatoria sp. moved towards CO2. HCO3 and O2 in light-dependent chemotactic reactions. No chemotaxis occurred in response to these substances in the dark. The chemotactic responses were detected after 2 h but became increasingly distinct up to 8 h. The chemotactically active concentration of CO2 was greater than the atmospheric concentration since trichomes moved from air towards a source of CO2. Using diffusivity coefficients it was calculated that trichomes of Oscillatoria sp. accumulated at a CO2 partial pressure of 0.02 bar (equivalent to 0.83 mM). With O2 as the chemoattractant the value was 0.35 bar (14.56 mM). These results are discussed with reference to the roles of inorganic carbon and O2 in cyanobacterial metabolism and it is concluded that chemotactic behaviour may be important in movements within the photic zone of sediment environments.