DIFFERENTIATION OF SERRATIA-MARCESCENS 274 INTO SWIMMER AND SWARMER CELLS
DIFFERENTIATION OF SERRATIA-MARCESCENS 274 INTO SWIMMER AND SWARMER CELLS
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DOI：
10.1128/jb.172.8.4322-4328.1990
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发表时间：
1990-08-01
影响因子：
3.2
通讯作者：
HARSHEY, RM
中科院分区：
文献类型：
--
作者：
ALBERTI, L;HARSHEY, RM
我们描述了一种新的感觉反应在肠道细菌粘质沙雷氏菌。当在液体培养基中生长时，细菌是具有一到两个鞭毛的短杆，并表现出典型的游泳行为。在转移到固体表面（0.7 - 0.8%琼脂培养基）后，细菌的形态发生了巨大的变化。它们停止分离，伸长并表达大量（10到100）覆盖细胞外侧的鞭毛。细菌现在表现出一种不同的运动形式——成群——这使得它们能够在固体表面的顶部快速移动。在固体或液体培养基上分别生长可逆转向游泳细胞或群集细胞的分化。为了确定影响这种分化的条件，对粘质葡萄的生长环境进行了广泛的调控。通过肉眼和显微镜观察细胞在固体表面上的运动来监测蜂群反应，通过免疫荧光标记，然后在显微镜下观察细长的、大量鞭毛细胞的存在，以及使用Western免疫印迹分析来估计鞭毛蛋白的诱导。对细菌运动施加物理限制的条件，如固体或粘性介质，在诱导群体反应方面是最有效的。虽然不能排除这种成分的存在，但无法确定介质中可能导致这种反应的化学成分。游泳细胞和群集细胞具有相同分子量的鞭毛蛋白，在胰蛋白酶的消化作用下产生相似的蛋白水解模式。结合先前在S. marcescens中发现的单个鞭毛编码基因（R. M. Harshey， G. Estepa, and H. Yanagi, gene 79:1-8, 1989），我们的结果表明，相同的蛋白质是游泳细胞和群细胞鞭毛的一个组成部分。因此，为了响应物理信号，单个鞭毛蛋白基因必须受到差异调节。我们讨论了感知这种信号的可能机制。
We describe a new sensory response in the enteric bacterium Serratia marcescens. When grown in liquid media, the bacteria were short rods with one to two flagella and displayed classical swimming behavior. Upon transfer to a solid surface (0.7 to 0.8% agar medium), the bacteria underwent a dramatic change of form. They ceased septation, elongated, and expressed numerous (10 to 100) flagella that covered the lateral sides of the cells. The bacteria now displayed a different form of locomotion-swarming-which allowed them to rapidly move over the top of the solid surface. The differentiation to either swimmer or swarmer cells could be reversed by growth on solid or liquid medium, respectively. To identify conditions that influence this differentiation, the growth environment of S. marcescens was manipulated extensively. The swarming response was monitored by visual and microscopic observation of cell movement on solid surfaces, by immunofluorescent labeling followed by microscopic observation for the presence of elongated, profusely flagellated cells, as well as by estimation of induction of flagellin protein, using Western immunoblot analysis. Conditions that imposed a physical constraint on bacterial movement, such as solid or viscous media, were the most efficient at inducing the swarming response. No chemical constituent of the medium that might contribute to the response could be identified, although the existence of such a component cannot be ruled out. Both swimmer and swarmer cells had flagellin proteins of identical molecular weight, which produced similar proteolysis patterns upon digestion with trypsin. Combined with an earlier demonstration of a single flagellin-encoding gene in S. marcescens (R. M. Harshey, G. Estepa, and H. Yanagi, Gene 79:1-8, 1989), our results suggest that the same protein is a component of both swimmer and swarmer cell flagella. Thus, in response to a physical signal, a single flagellin gene must be differential regulated. We discuss possible mechanisms for sensing such a signal.