Mucin promotes rapid surface motility in Pseudomonas aeruginosa.
Mucin promotes rapid surface motility in Pseudomonas aeruginosa.
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作者：
Yeung AT;Parayno A;Hancock RE
决定铜绿假单胞菌运动模式的一个重要环境因素是培养基的粘度，通常通过调节体外琼脂浓度来提供。然而，覆盖上皮表面的粘液层的粘性凝胶样性质主要是由于糖蛋白粘蛋白。已知铜绿假单胞菌在0.3%（wt/vol）琼脂内游动，并在具有氨基酸作为弱氮源的0.5%（wt/vol）琼脂的表面上群集。当将生理浓度或低至0.05%（wt/vol）的粘蛋白加入到游动琼脂中时，除了游动之外，还观察到铜绿假单胞菌在琼脂表面上经历高度加速的运动。在粘蛋白存在下的表面运动集落看起来是圆形的，具有明亮的绿色中心，被较厚的白色边缘包围。虽然完整的鞭毛所需的表面运动在粘蛋白的存在下，IV型皮利和鼠李糖脂的生产没有。用其他润湿剂代替粘蛋白表明粘蛋白的润滑性质可能有助于表面运动。基于对突变体的研究，群体感应系统（las和rhl）和孤儿自诱导受体QscR在这种形式的表面运动中发挥了重要作用。对取自运动区的细胞的转录分析揭示了参与毒力和抗性的基因的上调。基于这些结果，我们认为粘蛋白可能促进了一种新的或高度修饰的表面运动形式，我们建议将其称为"冲浪"。决定铜绿假单胞菌运动模式的一个重要因素是培养基的粘度，通常通过调节体外琼脂浓度来提供。然而，覆盖上皮表面的粘液层的凝胶样性质，例如肺的粘液层，假单胞菌感染的主要部位，主要是由糖蛋白粘蛋白的产生贡献的。在这项研究中，我们将粘蛋白添加到游泳培养基中，发现它促进了铜绿假单胞菌表现出快速表面运动的能力。这些运动集落呈圆形，明亮的绿色中心被较厚的白色边缘包围。有趣的是，在厚边缘的细菌细胞出现堆积，缺乏鞭毛，而在运动中心的细胞有鞭毛。我们从各种遗传和表型研究中获得的数据表明，粘蛋白可能促进了铜绿假单胞菌中一种改良形式的群集或一种新形式的表面运动。
An important environmental factor that determines the mode of motility adopted by Pseudomonas aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the viscous gel-like property of the mucus layer that overlays epithelial surfaces is largely due to the glycoprotein mucin. P. aeruginosa is known to swim within 0.3% (wt/vol) agar and swarm on the surface at 0.5% (wt/vol) agar with amino acids as a weak nitrogen source. When physiological concentrations or as little as 0.05% (wt/vol) mucin was added to the swimming agar, in addition to swimming, P. aeruginosa was observed to undergo highly accelerated motility on the surface of the agar. The surface motility colonies in the presence of mucin appeared to be circular, with a bright green center surrounded by a thicker white edge. While intact flagella were required for the surface motility in the presence of mucin, type IV pili and rhamnolipid production were not. Replacement of mucin with other wetting agents indicated that the lubricant properties of mucin might contribute to the surface motility. Based on studies with mutants, the quorum-sensing systems (las and rhl) and the orphan autoinducer receptor QscR played important roles in this form of surface motility. Transcriptional analysis of cells taken from the motility zone revealed the upregulation of genes involved in virulence and resistance. Based on these results, we suggest that mucin may be promoting a new or highly modified form of surface motility, which we propose should be termed “surfing.” An important factor that dictates the mode of motility adopted by P. aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the gel-like properties of the mucous layers that overlay epithelial surfaces, such as those of the lung, a major site of Pseudomonas infection, are contributed mostly by the production of the glycoprotein mucin. In this study, we added mucin to swimming media and found that it promoted the ability of P. aeruginosa to exhibit rapid surface motility. These motility colonies appeared in a circular form, with a bright green center surrounded by a thicker white edge. Interestingly, bacterial cells at the thick edge appeared piled up and lacked flagella, while cells at the motility center had flagella. Our data from various genetic and phenotypic studies suggest that mucin may be promoting a modified form of swarming or a novel form of surface motility in P. aeruginosa.