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Método de Fijación Determina la Ultraestructura del Nucleoide en Pseudomonas aeruginosa y Staphylococcus aureus

A E Grigor'eva¹, E S Ryabova², A V Tupitsyna²

¹Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia. feabelit@mail.ru.

Bulletin of experimental biology and medicine

|January 10, 2026

Abstract:

The structure of the nucleoid observed after standard aldehyde fixation did not correspond to modern ideas about its spatial organization: DNA strands are not seen in Staphylococcus aureus and appear stuck together (2-15 nm) in Pseudomonas aeruginosa. The Ryter-Kellenberger (RK) fixation involving incubation in 1 % osmium tetroxide (pH 6.0) followed by 0.5 % uranyl acetate (pH 3.0) effectively preserves DNA strands (2 nm). The RK method also revealed additional details of the envelope structure in gram-positive and gram-negative bacteria. However, ribosomes, observed as spherical particles in aldehyde-fixed samples, were not visualized in the cytoplasm of S. aureus after RK fixation. The study provided a new information on the ultrastructure of bacteria, which is necessary for understanding the mechanisms of antibacterial compounds effects.

Palabras clave:

Pseudomonas aeruginosa Staphylococcus aureus fijación análisis morfológico

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