Intracellular Structures in Negatively Stained Bacteria

Abstract

Intact bacteria have been examined after negative staining with five compounds commonly used to reveal ultrastructure in biological material. Escherichia coli, Proteus vulgaris, Spirillum serpens, Bacillus pumilus, Bacillus circulans and Bacillus anthracis were employed. Exponential phase cells on agar containing 1%. trypticase and 0.2% yeast extract were washed off with distilled water to yield suspensions containing 109 to 1011 cells/ml. Aqueous solutions of potassium phosphotungstate, pH 6.8 to 7.2 (KPT), lithium tungstate, pH 7.1 (LiT), sodium tungstate, pH 7.1 (NaT), ammonium molibdate, pH 7.0 (AM) and urnyl acetate EDTA complex, pH 6.8 (UA/EDTA) were used to stain the cells.