Electron microscopy for virus identification and virus assemblage characterization
5µL of an enrichment culture , or 0.2 µm filtered and centrifuged ( 10 min at 3000g ) cell - free supernatant , is spotted onto carbon / formvar - coated electron microscope grids ( Ted Pella or EM Sciences ) .
It is then allowed to absorb for 2 min .
Remove sample from grid by slowly bringing a small ( ca . 1cm2 ) piece of filter paper perpendicular to the grid to the side of the grid .
The sample will be removed by wicking .
Stain grid by placing on a 5μL drop of 2 % Uranyl Acetate ( or Phosphotungstate ) for 15 - 30 seconds .
Remove stain by wicking as above .
Air dry for at least 10 minutes .
Samples are examined by transmission electron microscopy ( TEM ) , e . g . , JEOL 100 cx , operated at 100 keV .
