Fungal Spore Characterization by SEM

After incubation with heavy metals, the fungal materials (spores) were separated by centrifugation, fixed with 1% glutaric aldehyde (15 min), then treated with 2% OsO₄ in phosphate-bufferd saline (PBS, pH 7.4), washed and dehydrated in an increasing ethanol gradient (50%, 80%, 100%) in water. The uncut samples were sprayed with nanogold particles prior to observations with scanning electron microscopy (SEM, model JSM 630 F, Jeol) at 5–15 kV in the secondary electron mode. The sites of metal adsorption and precipitations were observed by using the SEM’s back scattering detector. A silicon peak detected is due to sample fixing on glass slides, traces of chloride and calcium peaks may also arise from the incubation medium. The elemental analysis of microbiomes, spores and cellwalls of EH8, EH10 and EH11 was carried out using eXL EDX-system (Oxford instruments). For this purpose, X-ray quanta were detected by a silicon detector, the data were analyzed using energy dispersive x-ray analysis software and the signals of element specific shells were resolved and annotated using Link-ISIS software^{5 (link)}.