Dependence of the Bacillus subtilis biofilm expansion rate on phenotypes and the morphology under different growing conditions

Abstract

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.

Adaptation of Escherichia coli Biofilm Growth, Morphology, and Mechanical Properties to Substrate Water Content

“…Interestingly, the macromorphology of E. coli AR3110 biofilms appears to be comparable to the morphology of B. subtilis and V. cholerae biofilms all characterized by the emergence of long radial wrinkles and delaminated buckles ( Figure 1 A). 7 , 8 , 12 , 15 , 34 However, recent work comparing various mutants of matrix-producing E. coli reported distinct micromorphologies, 19 thereby illustrating the crucial role of the composite nature of the matrix in biofilm morphogenesis. Further dynamic and quantitative studies of biofilm mechanics are required to verify in which conditions the mechanisms proposed for other biofilm-forming bacterial species would apply for E. coli .…”

Bacillus subtilisimpact on plant growth, soil health and environment: Dr. Jekyll and Mr. Hyde

“…The application of nanohydroxyapatite (NHAP) along with B. subtilis to cadmium contaminated soil improved soil remediation and increased rhizospheric community (Liu et al, 2018). UV-mutated species B. subtilis 38, served as an efficient sorbent of Hg, Cr, Cd and Pb (Wang et al, 2019). Certain species of B. subtilis (DBM) have been found to survive in heavy metal contaminated soils, where DBM mineral complexes were formed by phosphodiester bond formation thereby restricting the entry of heavy metals into the bacterial cells as well as increasing its Cu and Pb sorption ability (Bai et al, 2019).…”

Cell differentiation and motion determine the Bacillus subtilis biofilm morphological evolution under the competitive growth

“…We make plots of the cell velocity in different directions, as shown in Figure 4c-h. By comparing Figures 4f and 1g, we find that the cell velocity within the biofilm is an order of magnitude less than the expansion speed at the biofilm edge, which is the same as the situation when the biofilm grows alone [22]. For the biofilm with inoculating distance d = 11 mm, there is no saltation in cell velocities from the inoculation center outward along the radius, but outermost cells tend to move faster, which means the outer cells are active than inner, as shown in Figure 4f.…”