Researches on the diversity of growing patterns in biological systems

细菌根据环境条件如营养浓度和基质硬度的变化形成特征和多样的菌落。这意味着细菌通过集体或多细胞与环境相互作用而活跃地生活，而不是单细胞和被动地生活。为了阐明生物有机体的这种集体行为，我们从微观和宏观两个方面研究了细菌的生长机制和菌落形成的形态变化。我们已经建立了形态图时，改变营养浓度和基板的柔软度。我们还阐明了枯草芽孢杆菌和奇异变形杆菌的各种菌落形态的生长条件和特征。从理论上讲，我们已经彻底研究了如何从反应扩散方法来描述我们的实验观察。所有这些结果不仅有助于细菌菌落形成的研究，而且有助于扩大一般生物有机体群体模式形成的实验和理论研究。奇异变形杆菌通过交替地重复集体迁移和休息，在宏观上形成几乎完美的同心环状菌落，具有近似相等的间距。我们阐明了同心环状菌落重复界面生长的现象学机制。

Bacteria form characteristic and diverse colonies according to variation of environmental conditions such as nutrient concentration and substrate hardness. This implies that bacteria live actively by interacting collectively or multicellularly with their environment, instead of living unicellularly and passively. In order to elucidate this kind of collective behavior of biological organisms we have studied the growth mechanism and morphological change in colony formation of bacteria both microscopically and macroscopically. We have established morphological diagrams when varying both nutrient concentration and substrate softness. We have also elucidated the growth conditions and characteristics of various colony patterns for species Bacillus subtilis and Proteus mirabilis. Theoretically we have thoroughly investigated how well we can describe our experimental observations from the reaction-diffusion approach. All these results contribute not only to the study of colony formation of bacteria but also to the enlargement of experimental and theoretical studies on pattern formation of the population of biological organisms in general. The species Proteus mirabilis forms macroscopically almost perfect concentric-ring like colonies with approximately equal spacing by repeating collective migration and rest alternately. We have elucidated phenomenological mechanism for the repeated interface growth of the concentric-ring like colonies.