Journal: Materials

Article Title: Bio-Derived Cellulose Nanofibers for the Development Under Environmentally Assessed Conditions of Cellulose/ZnO Nanohybrids with Enhanced Biocompatibility and Antimicrobial Properties

doi: 10.3390/ma19020346

Figure Lengend Snippet: MIC and MBC values of both cellulose nanofiber–ZnO nanohybrids as well as the parent anionic and cationic cellulose nanofibers against E. coli and S. aureus bacteria.

Article Snippet: Bacterial Strains and culture conditions: In this study, Gram (−) Escherichia coli strain DH5 α ( E. coli , NCBI Taxonomy ID: 668369) and Gram (+) Staphylococcus aureus strain ATCC 25,923 ( S. aureus ) were employed to evaluate the antibacterial activity of both a-CNF/ZnO and c-CNF/ZnO nanohybrids, as well as the parent anionic and cationic cellulose nanofibers, following the CLSI guidelines (documents M07-A9 and M26-A [ , ]).

Techniques: Bacteria

Journal: bioRxiv

Article Title: Mechanical strain modulates Min patterning and division in E. coli filaments

doi: 10.1101/2025.02.21.638242

Figure Lengend Snippet: A . Phase contrast images of a representative E. coli filament growing on 10 µ g/ml aztreonam agarose pads. Following cell segmentation and tracking (Methods), the curvature of the filaments is computed along the midline. At a given location (e.g. yellow point) the curvature, | κ |, is computed as the inverse of the radius of the circumference that is tangent to that point (green circle): | κ | = 1 /R . As time progresses and the filament grows, the snapshots reveal a buckling instability where large values of | κ | are reached by the central region of the filament (see E ). B . Cartoon of the mechanical toy model. Forces are exerted by a chain of connected springs (black). Nodes (grey circles) are subjected to elastic and bending forces. Due to cellular growth, the elastic energy relies on the time-dependent distance, L ( t ), between consecutive nodes (Methods). Bending energy depends on the angle θ as determined by neighboring segments. C . Snapshots of a simulated growing filament (initial length: 50 µ m; doubling time: 50 min). Color scales for each time point indicate the elastic (top) and bending (bottom) energies using pair-wise moving average coordinates (Methods). As time progresses elastic energy accumulates by the central region. Buckling leads to a relaxation of the elastic energy at the expense of an increase of the bending energy (black triangles). D . Ratio of the total energy between soft and stiff filaments (soft: ; stiff: sample size: n = 100 simulations). As time progresses the panel shows that stiff filaments that are not able to buckle increase their energy. E . Density histograms of the curvature of filaments as a function of the relative position as obtained in experiments (left) and simulations (pair-wise moving average coordinates; right). Sample size: n = 22 (experiments) and n = 100 (simulations). The color scale represents probability. Larger curvatures (buckling) accumulate by the central region of the filament.

Article Snippet: Experiments were conducted using the Escherichia coli strain DH5 α (NZYTech), transformed with the plasmid pYLS68 (P lac -YFP::minD minE::CFP), generously provided by Dr. Shih [ ].

Techniques:

Journal: bioRxiv

Article Title: Mechanical strain modulates Min patterning and division in E. coli filaments

doi: 10.1101/2025.02.21.638242

Figure Lengend Snippet: A . Fluorescence channel (YFP, false color scale) of the illustrative filament shown in ( t = 30 min). The zoomed region (circle) highlights the increase of MinD in buckled regions. In addition, the white arrows indicate the anti-correlation effect between MinD and locations with a high curvature. B . Top: Kymographs of the filament shown in panel A representing curvature (top) and MinD intensity (middle) profiles along the filament middle axis as a function of time. Color scales account for the curvature ( µ m −1 ) and for MinD concentration (arbitrary units). The zoomed region in the MinD kymograph indicates the period, T , and the wavelength, λ , of the MinD standing-wave pattern. Bottom: Overlay of the time average of MinD and curvature profiles. Black arrows highlight the locations pinpointed in panel A by means of white arrows. Averages are computed within the region delimited by the white dashed lines. C . Violin plots showing the distribution of values of the Pearson’s correlation coefficient between MinD and curvature (sample size: n = 19 filaments where high and low curvature regions were analyzed separately, , Methods). Black solid lines represent the mean (Low: 0.22; High: −0.14). D . Normalized MinD intensity (mean and standard deviation) as a function of the curvature in non-patterned agarose pads (same dataset as in C ) and in micro-patterned growth substrates ( n = 20 filaments). Solid lines are, in both cases, a logarithmic fit: , Methods. Inset: Illustrative phase contrast image of an E. coli filament growing in a micro-patterned agarose pad (scale bar: 10 µ m).

Article Snippet: Experiments were conducted using the Escherichia coli strain DH5 α (NZYTech), transformed with the plasmid pYLS68 (P lac -YFP::minD minE::CFP), generously provided by Dr. Shih [ ].

Techniques: Fluorescence, Concentration Assay, Standard Deviation