Biofilms are communities of tightly associated bacteria encased in an extracellular matrix and attached to surfaces of various objects, such as liquid or solid surfaces. Here we use the multi-channel wide field stereo fluorescence microscope to characterize growth of the Bacillus subtilis biofilm, in which the bacterial strain was triple fluorescence labeled for three main phenotypes: motile, matrix producing and sporulating cells. We used the feature point matching approach analyzing time lapse experimental movies to study the biofilm expansion rate. We found that the matrix producing cells dominate the biofilm expansion, at the biofilm edge, the expansion rate of matrix producing cells was almost the same as the velocity of the whole biofilm; however, the motile and sporulating cells were nearly rest. We also found that the biofilm expansion rate evolution relates to cell differentiation and biofilm morphology, and other micro-environments can influence the biofilm growth, such as nutrient, substrate hardness and colony competition. From our work, we get a deeper understanding of the biofilm growth, which can help us to control and to further disperse the biofilm.

中文翻译：

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枯草芽孢杆菌生物膜扩展速率对表型和形态在不同生长条件下的依赖。

生物膜是紧密结合的细菌群落，被包裹在细胞外基质中并附着于各种物体的表面，例如液体或固体表面。在这里，我们使用多通道宽视野立体荧光显微镜来表征枯草芽孢杆菌生物膜的生长，其中细菌菌株被三重荧光标记为三种主要表型：运动型，基质产生型和孢子形成细胞。我们使用特征点匹配方法分析延时实验电影，以研究生物膜膨胀率。我们发现，产生基质的细胞在生物膜的膨胀中占主导地位，在生物膜的边缘，产生基质的细胞的膨胀速率几乎与整个生物膜的速度相同；然而，运动和芽胞几乎处于静止状态。我们还发现生物膜膨胀速率的演变与细胞分化和生物膜形态有关，其他微环境也会影响生物膜的生长，例如营养，底物硬度和菌落竞争。通过我们的工作，我们对生物膜的生长有了更深入的了解，这可以帮助我们控制和进一步分散生物膜。