Monitoring of Wild Pseudomonas Biofilm Strain Conditions Using Statistical Characterization of Scanning Electron Microscopy Images

Sinha, Suparna; Das, Saptarshi; Tarafdar, Sujata; Dutta, Tapati

doi:10.1021/acs.iecr.7b01106

Cited by 7 publications

(3 citation statements)

References 100 publications

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“…Understanding biofilm proliferation, development, processes and behavior under certain conditions is crucial in order to optimize and control the cultivated technological or biological system. Direct analysis of biofilm behavior or rather structure can be performed using different imaging techniques such as confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) or atomic force microscopy (AFM) [8,[13][14][15]. While CLSM can be used for investigating the biofilm matrix composition (e.g., DNA and EPS) in a range of several micrometers, SEM together with energy-dispersive X-ray spectroscopy (EDX) examines biofilms up to 1 nm resolution including their elemental composition.…”

Section: Introductionmentioning

confidence: 99%

Impact of Fe2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms—A Bacillus subtilis Case Study

2022

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Bivalent cations are known to affect the structural and mechanical properties of biofilms. In order to reveal the impact of Fe2+ ions within the cultivation medium on biofilm development, structure and stability, Bacillus subtilis biofilms were cultivated in mini-fluidic flow cells. Two different Fe2+ inflow concentrations (0.25 and 2.5 mg/L, respectively) and wall shear stress levels (0.05 and 0.27 Pa, respectively) were tested. Mesoscopic biofilm structure was determined daily in situ and non-invasively by means of optical coherence tomography. A set of ten structural parameters was used to quantify biofilm structure, its development and change. The study focused on characterizing biofilm structure and development at the mesoscale (mm-range). Therefore, biofilm replicates (n = 10) were cultivated and analyzed. Three hypotheses were defined in order to estimate the effect of Fe2+ inflow concentration and/or wall shear stress on biofilm development and structure, respectively. It was not the intention to investigate and describe the underlying mechanisms of iron incorporation as this would require a different set of tools applied at microscopic levels as well as the use of, i.e., omic approaches. Fe2+ addition influenced biofilm development (e.g., biofilm accumulation) and structure markedly. Experiments revealed the accumulation of FeO(OH) within the biofilm matrix and a positive correlation of Fe2+ inflow concentration and biofilm accumulation. In more detail, independent of the wall shear stress applied during cultivation, biofilms grew approximately four times thicker at 2.5 mg Fe2+/L (44.8 µmol/L; high inflow concentration) compared to the low Fe2+ inflow concentration of 0.25 mg Fe2+/L (4.48 µmol/L). This finding was statistically verified (Scheirer–Ray–Hare test, ANOVA) and hints at a higher stability of Bacillus subtilis biofilms (e.g., elevated cohesive and adhesive strength) when grown at elevated Fe2+ inflow concentrations.

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Section: Introductionmentioning

confidence: 99%

Impact of Fe2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms—A Bacillus subtilis Case Study

2022

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“…Studies related to the application of scanning electron microscopy (SEM) [30] and atomic force microscopy (AFM) [25,31] are of great importance, especially in fractal analysis. The authors of [25] studied the three-dimensional surface micromorphology of zinc/silverparticle-composite antibacterial coatings.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Geometric Structure of X39Cr13 Steel upon Thermochemical Treatment Specific to Medical-Grade Steels

2022

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This paper presents the results of the multi-aspect surface characterization of X39Cr13 steel samples subjected to technological processes specific to medical instrumentation, such as heat and thermochemical treatment, as well as sterilization, which are implemented in corrosion resistance measurements. The application of numerical methods of fractal analysis to averaged profiles obtained from SEM images resulted in double-log plots of structure function, from which the determination of the fractal parameters of interest was possible. The discussion was focused on the fractal dimension D, which governs relative height variations upon scaling in length, and corner frequency fc, which separates the scaling behavior of different-order structures (particles and their aggregates). The obtained results show that the heat treatment leaves behind a granular structure of steel (D2 = 2.43; fc2 = 1.97 nm), whereas corrosion tests reveal the appearance of pits (D1 = 2.17; fc1 = 0.303 nm; D2 = 2.59; fc2 = 4.76 nm). In turn, the ion nitriding improves the resistance of steel X39Cr13 to local corrosion. The fractal analysis also shows that the structure of the nitrided layer differs insignificantly from that of the untreated material, seen only as a shortening of the radius of the self-similarity area by a factor of two (fc2 = 1 nm).

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“…In order to optimize biofilm-technological processes it is necessary to understand biofilm proliferation and behavior under certain conditions. Direct analysis of bioflm behavior or rather structure can be performed using different imaging techniques such as confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) or atomic force microscopy (AFM) (Allen, Habimana, & Casey, 2018;Azeredo et al, 2016;Bridier, Meylheuc, & Briandet, 2013;Dutta Sinha, Das, Tarafdar, & Dutta, 2017). While CLSM can be used for investigating the biofilm matrix composition (e.g., DNA and EPS) in a range of several micrometers, SEM together with energy-dispersive X-ray spectroscopy (EDX) examines biofilms up to 1 nm resolution and their elemental composition.…”

Section: Introductionmentioning

confidence: 99%

Development and structure of Bacillus subtilis biofilms manipulated by Iron(II) addition during cultivation at different shear stress conditions

Gierl

Horn

Wagner

2021

Preprint

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Bivalent ions such as Ca2+ and Mg2+ are known to affect the structural and mechanical properties of biofilms. In order to reveal the impact of Fe2+ ions within the cultivation medium on biofilm development, structure and stability, Bacillus subtilis biofilms were cultivated in mini-fluidic flow cells. Two different Fe2+ inflow concentrations (0.25 and 2.5 mg/L, respectively) and wall shear stress levels (0.05 and 0.27 Pa, respectively) were tested. Biofilm structure was determined daily in situ and non-invasively by means of optical coherence tomography. A set of ten structural parameters was used to quantify biofilm structure, its development and change. Moreover, for each experiment ten replicates were cultivated and analyzed allowing for valid conclusions. Fe2+ addition influenced biofilm development (e.g., biofilm accumulation) and structure markedly. Experiments revealed the accumulation of FeO(OH) within the biofilm matrix and a positive correlation of Fe2+ inflow concentration and biofilm accumulation. Even at elevated shear stress levels this correlation was valid. In more detail, independent of the wall shear stress applied during cultivation over ten days biofilms grew approximately four times thicker at 2.5 mg Fe2+/L compared to low Fe2+ inflow concentrations of 0.25 mg/L. This finding hints on a higher stability of Bacillus subtilis biofilms against detachment when growing at elevated Fe2+ concentrations.

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Monitoring of Wild Pseudomonas Biofilm Strain Conditions Using Statistical Characterization of Scanning Electron Microscopy Images

Cited by 7 publications

References 100 publications

Impact of Fe2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms—A Bacillus subtilis Case Study

Impact of Fe2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms—A Bacillus subtilis Case Study

Evolution of the Geometric Structure of X39Cr13 Steel upon Thermochemical Treatment Specific to Medical-Grade Steels

Development and structure of Bacillus subtilis biofilms manipulated by Iron(II) addition during cultivation at different shear stress conditions

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