Bacterial Mass Behavior in Colony Morphogenesis.

细菌在固体培养基上通过连续的细胞增殖和群集形成具有特征形态和内部结构的菌落。通过分析细菌的形态发生过程，发现细菌是具有群体行为的有机体，本研究利用CCD摄像机对细菌群体行为进行跟踪和录像，以便于精确分析。通过转座子诱变获得粘质沙雷氏菌的突变株，并对其协同易位、相互转化等群体行为的基本机制进行了突变分析。1.粘质沙雷氏菌在低琼脂培养基上的铺展生长过程中，生物表面活性剂“serrawettin”的产生至关重要。各种突变分析表明，生物表面活性剂在细菌的群体迁移行为中发挥了重要作用。2.奇异变形杆菌对特定氨基酸的存在表现出特异性的群集行为。这种行为是奇异变形杆菌群体的固体培养基特异性反应，奇异变形杆菌点接种到半固体培养基的中心表面，迅速扩散到整个表面。在此之后，这些细菌进入了特定的阶段，并表现出特征性的时空模式，例如，云纹状动态图案、群集细菌的多焦点聚集以及这些聚集体的移位和融合。从上述发现可以明显看出，表面环境中的细菌是合作生活的。对这些特征行为的实验分析将揭示细菌在自然界中真实的生活模式。3.作为随机模式生长的典型例子，对枯草芽孢杆菌菌落生长界面的自亲和性进行了研究。通过行为数据的定量分析，α（粗糙度指数）=0.5和0.78取决于界面生长的微观模式的值。

Bacteria form a colony with characteristic morphology and internal structure by successive cell multiplication and swarming on a solid medium. By analyzing processes of such morphogenic growth, we found that bacteria are organism exerting mass behavior.In the present study, such bacterial mass behavior was traced by CCD camera and video-recorded for precise analyzes. Mutants of Serratia marcescens were collected by transposon mutagenesis for mutational analyzes of fundamental protocols in mass behavior, such as cooperated translocation, mutual recognition.1.In a spreading growth of flagellum-less S.marcescens on a lowagar medium, production of biosurfactant "serrawettin" was shown to be critical. Roles of biosurfactants in translocating mass behavior of bacteria were indicated by various mutational analyzes.2.Proteus mirabilis exhibited specific swarming behavior in response to the presence of a specific amino acid. Such behavior was a solid medium-specific response of a P.mirabilis population.P.mirabilis point-inoculated onto the central surface of a semi-solid medium, promptly spread on the whole surface. These bacteria residing on the surface, therafter, entered into the special phase and demonstrated characteristic spatio-temporal pattern, e.g., Moire-like dynamic pattern, multifocal aggregation of swarming bacteria, and translocation and fusion of such aggregates.From findings described above, it is evident that bacteria on a surface environment are living in cooperation. Experimental analysis of these characteristic behavior will uncover bacterial real mode of life in nature.3.Growing interface of a Bacillus subtilis colony was examined for self-affinity, as a typical example of random pattern growth. By quantitative analysis of behavioral data, the values of alpha (roughness exponent) =0.5 and 0.78 depending on microscopic mode of interface growth were obtained.