Sievert Stefan M, Wieringa Elze B A, Wirsen Carl O, Taylor Craig D
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Environ Microbiol. 2007 Jan;9(1):271-6. doi: 10.1111/j.1462-2920.2006.01156.x.
Studies were conducted in opposing gradients of oxygen and sulfide in microslide capillaries to (i) characterize the chemical microenvironment preferred by Candidatus Arcobacter sulfidicus, a highly motile, sulfur-oxidizing bacterium that produces sulfur in filamentous form, and (ii) to develop a model describing the mechanism of filamentous-sulfur formation. The highly motile microorganisms are microaerophilic, with swarms effectively aggregating within oxic-anoxic interfaces by exhibiting a chemotactic response. The position of the band was found to be largely independent of the sulfide concentration as it always formed at the oxic-anoxic interface. Flux calculations based on steady state gradients of oxygen and sulfide indicate that sulfide is incompletely oxidized to sulfur, in line with the formation of filamentous sulfur by these organisms. It is proposed that Candidatus Arcobacter sulfidicus effectively competes with other sulfur-oxidizing bacteria in the environment by being able to tolerate higher concentrations of hydrogen sulfide (1-2 mM) and by possessing the ability to grow at very low oxygen concentrations (1-10 muM). The formation of mat-like structures from filamentous sulfur appears to be a population mediated effort allowing these organisms to effectively colonize environments characterized by high sulfide, low oxygen and dynamic fluid movement.
研究在微载玻片毛细管中的氧气和硫化物反向梯度条件下进行，目的是：（i）表征丝状硫氧化菌“候选嗜硫嗜氧弧菌”（Candidatus Arcobacter sulfidicus）偏好的化学微环境，该菌运动性很强，能产生丝状硫；（ii）建立一个描述丝状硫形成机制的模型。这些运动性很强的微生物是微需氧菌，菌团通过趋化反应在有氧 - 缺氧界面有效聚集。发现菌带位置在很大程度上与硫化物浓度无关，因为它总是在有氧 - 缺氧界面形成。基于氧气和硫化物稳态梯度的通量计算表明，硫化物未完全氧化为硫，这与这些生物体形成丝状硫的情况相符。有人提出，“候选嗜硫嗜氧弧菌”能够耐受更高浓度的硫化氢（1 - 2 mM），并能在极低氧气浓度（1 - 10 μM）下生长，从而在环境中有效地与其他硫氧化细菌竞争。丝状硫形成类似垫子的结构似乎是群体介导的过程，使这些生物体能够有效地在以高硫化物、低氧气和动态流体运动为特征的环境中定殖。
