Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: eDNA colocalizes with exopolysaccharides (EPS) in the extracellular matrix (ECM) of both non-developmental and developmental Myxococcus xanthus biofilms. (A) Quantitative colocalization analysis of the STYOX orange and Alexa 350-conjugated WGA fluorescent signals. The colocalization colormap is shown in the upper panel. The hot color represents a positive correlation, and the cold color represents a negative correlation. Further color divisions within groups are indicated by the color scale bar. In the lower panel, the histogram was generated from the calculated colocalization coefficient (M1 and M2), Pearson’s correlation coefficient (PCC), and an intensity correlation quotient (ICQ; n = 5). (B) The fluorescence pixel ratio (red/blue) of the samples with/without DNase I treatment. The significance was determined by Student’s t -test ( n = 5; *** p < 0.001). (C) The non-developmental biofilm (24 h) formed by Myxococcus xanthus DK10547 (live cells, GFP-green) was stained with SYTOX orange (eDNA and dead cells, red) and FM 4-64 (cell membrane, blue). Scale bars represent 20 μm.

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: Generated, Fluorescence, Staining

Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: DNA interacts with both i- and s-EPS of Myxococcus xanthus in vitro . (A) Result of the precipitation assay. The representative photograph of the sample after centrifugation is shown in the upper panel. The fluorescence intensity of the supernatant was measured at an excitation wavelength of 518 nm and an emission wavelength of 620 nm (lower panel; n = 3; *** p < 0.001). (B) Isothermal titration calorimetry (ITC) profile for the titration of s-EPS with DNA. The upper panel represents the raw data for the sequential injections of s-EPS into DNA solution, and the lower panel shows the integrated and dilution-corrected data peak area plotting of the titration data.

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: In Vitro, Centrifugation, Fluorescence, Isothermal Titration Calorimetry, Titration

Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: Visualization of the DNA, exopolysaccharides (EPS), and DNA-EPS complex. Representative TEM (A) and atomic force microscopy (AFM; B ) observations of Myxococcus xanthus chromosomal DNA (DNA), insoluble EPS (i-EPS), DNA-insoluble EPS complex (DNA + i-EPS), soluble EPS (s-EPS), and DNA-soluble EPS complex (DNA + s-EPS). Scale bars represent 200 nm in (A) and 500 nm in (B) . The particle diameter of the aggregates (C) and the porosity of the molecules (D) observed by atomic force microscopy (AFM) were measured by ImageJ software ( n = 20; ** p < 0.01; *** p < 0.001).

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: Microscopy, Software

Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: Nanomechanical strength of DNA-EPS complex. (A) Specific viscosity of DNA, exopolysaccharides (EPS) and DNA-EPS complex. (B) SEM images of native (upper panel) or DNase I treated (lower panel) Myxococcus xanthus DK1622 biofilms. Scale bars represent 5 μm. (C) Representative force curves and atomic force microscopy (AFM) images of native (upper panel) or DNase I treated (lower panel) Myxococcus xanthus DK1622 biofilms. Scale bars represent 5 μm. (D) The average adhesion force between extracellular matrix (ECM) with (+) or without (−) eDNA and the tip of AFM cantilever. ** p < 0.01.

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: Microscopy

Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: Susceptibility of native and DNase I treated Myxococcus xanthus biofilms to the surfactants and antibiotics. The native (DNase I−) and DNase I treated (DNase I+) DK1622 non-developmental biofilms were prepared. (A) The relative biofilm removal efficiency was quantified by crystal violet stain after SDS or CPC treatment, respectively. (B) The killing percentage by streptomycin and spectinomycin to the cells within biofilms was determined by colony forming unit (CFU) counting, respectively. ** p < 0.01.

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: Staining

Journal: Frontiers in Microbiology

Article Title: Physicochemical and Biological Insights Into the Molecular Interactions Between Extracellular DNA and Exopolysaccharides in Myxococcus xanthus Biofilms

doi: 10.3389/fmicb.2022.861865

Figure Lengend Snippet: Susceptibility of Myxococcus xanthus SW504 cells to the extrinsically supplied DNA. Growth curves of Myxococcus xanthus SW504 cells in the CTT medium supplemented with (+) or without (−) 0.5% ( w / v ) calf thymus DNA were plotted by measuring the optical density at 600 nm (A) and colony forming unit (CFU) counting (B) .

Article Snippet: Myxococcus xanthus DK1622 nondevelopmental biofilm was cultured in 24-well flat-bottom cell culture plates (NEST Biotechnology, China) for 24 h as described above, and 200 μg/ml DNase I was supplemented if needed.

Techniques: