Multicellular Behavior of Bacteria and Dynamics of Their Colony Formation

我们研究了生长机制和形态学变化，从模式形成的物理学的观点出发，研究了细菌的菌落形成。根据细菌物种的大小、形状和颜色，殖民地的差异。这也将以敏感的方式改变其形式，以适应环境状况的变化。这一点表明，也可能是常见的细菌，如大肠杆菌，被归类为单细胞组织，它们从来不制造，它们独立和随机，但在某种程度上协作多细胞。We have thus tried to extract some simple， and universal beManagement iors in growth from such complex bacterial systems.Here we varied only two parameters to investigate the colony growth; concentrations of nutrient C-D2 and agar C-D2 in a thin agar plate as the incubation medium。Other Parameters specifying experimental conditions such as temperature were kept constant.我们主要使用了一种典型的细菌物种Bacillus subtilis。另一方面，实验程序是标准的。It was found that coloniels show teristic patterns in the specific regions of values of CイイD2nイイD2 and CイD2aイエD2 in the morphological diagram and the pattern change drastically from one region to another。它们分为五种类型：分形DLA类、紧凑型伊甸园类、集中环形类、简单磁盘类和有弹性分支的DBM类。We have experimentally elaborated characteristic properties for each of these colony pattern.We have also done the same experiments for a bacterial species Proteus mirabilis。这个物种已经被认为比一个世纪更好，以至于在宏观上形成几乎完美的连贯环，殖民地，在半固体基底的表面上接近相等的空间，作为一个琼脂板。我们有一个典型的宏观和生理学机制，用于类似concentric-ring的殖民地的重复接口的增长。

We have studied the, growth mechanism and morphological change, in colony formation of bacteria from the viewpoint of physics of pattern formation. The colony differs in size, form, and color according to bacterial species. It also changes its form sensitively with the variation of environmental conditions. This implies that although usual bacteria such as Escherichia coli are regarded as single cell organisms, they never make, their colony independently and randomly but somehow collaborate multicellularly. We have thus tried to extract some simple, and universal behaviors in growth from such complex bacterial systems.Here we varied only two parameters to investigate the colony growth; concentrations of nutrient CィイD2nィエD2 and agar CィイD2aィエD2 in a thin agar plate as the incubation medium. Other parameters specifying experimental conditions such as temperature were kept constant. We mainly used a typical bacterial species Bacillus subtilis. Otherwise the experimental procedures are standard. It was found that coloniels show characteristic patterns in the specific regions of values of CィイD2nィエD2 and CィイD2aィエD2 in the morphological diagram and the patterns change drastically from one region to another. They were classified into five types; fractal DLA-like, compact Eden-like, concentric ring-like, simple disk-like and densely branched DBM-like. We have experimentally elaborated characteristic properties for each of these colony patterns.We have also done the same experiments for a bacterial species Proteus mirabilis. This species has been well-known for more than a century to form macroscopically almost perfect concentric-ring like, colonies with approximately equal spacings on the surface of semi-solid substrate such as an agar plate. We have elucidated macroscopic and phenomenological mechanism for the repeated interface growth of the concentric-ring like colonies.