Mira3 lmu scanning electron microscope

Scanning electron microscopy. The C. albicans biofilms were prepared on an 8-well chamber slide (Eppendorf, Hamburg, Germany), according to Tsang et al. [24 (link)], with some modifications. Briefly, the slides were washed twice with PBS, dehydrated in a series of ethanol solutions (20% for 10 min, 50% for 10 min, 70% for 10 min, and 96% for 15 min), and dried overnight in a lyophilizer (at 1.5 mbar) prior to sputter-coating with gold. The surface topographies of the C. albicans biofilms were viewed with a MIRA3 LMU scanning electron microscope (Tescan, Brno, Czech Republic).
Atomic force microscopy. The biofilms were formed for the SEM investigation, and drying was performed under air for 12 h. The atomic force microscopy was performed using Integra NT-MDT (NT-MDT, Zelenograd, Russia) in the tapping mode. The microscopy investigation was carried out using the NSG01 cantilever (Tipsnano, Tallinn, Estonia) with a spring constant of ~5.1 N/m. Preliminarily, wide scanning of about 70 × 70 μm was conducted to produce a reference map of the sample surface in order to localize the yeast cells. The scan size was then set with a sampling of 512 by 512 points and a scan rate of 0.5 Hz. The topographic, amplitude and phase images were acquired simultaneously.

For scanning electron microscopy, samples of bacterial cells before and after contact with ground vermiculite, where the resulting bacterial-clay sediments were washed twice, were fixed in 2.5%(vol) glutaraldehyde in 0.1 M phosphate buffer, pH 7.2. Samples were then washed twice with phosphate buffer and dehydrated through a 25–100% ascending series of ethanol in distilled water, being left for 20 min at each stage. Two transfers were made in 100% ethanol, and the samples were dried by the critical point method. Air-dried control samples of ground vermiculite were used. The mounted samples were sputter-coated with 30 nm Au/Pd using Gatan Pecs 682 (Gatan Inc., Pleasanton, CA, USA). Scanning electron microscopy (SEM) was performed using a Tescan Mira 3 LMU scanning electron microscope (Tescan, Brno, Czech Republic).

The nodules for electron microscopy were harvested at day 21 after inoculation. The electron microscopy protocol was as previously described (Serova et al., 2018 (link)). Samples were embedded in Epon (Honeywell Fluka™, Fisher Scientific, Loughborough, United Kingdom). For transmission electron microscopy, ultrathin sections were cut on a Leica EM UC7 ultramicrotome (Leica Microsystems, Vienne, Austria). The nodule tissues were examined and photographed under a JEM-1400 transmission electron microscope (JEOL Corporation, Tokyo, Japan) at 80 kV.
For scanning electron microscopy, nodules were prepared as previously described (Tsyganova et al., 2021 (link)). The samples were observed in a Tescan MIRA3 LMU scanning electron microscope (Tescan, Brno, Czech Republic) at 9 kV.