The present study on the ultrastructure of Bacillus subtilis was undertaken in order to examine by means of the freeze-etching technique possible structural changes occurring during the chemical fixation procedure (Ryter-Kellenberger (R-K) fixation). Three stages were followed by freeze-etching, viz.: (a) fixation in osmium tetroxide, (b) fixation in osmium tetroxide and posttreatment with uranyl acetate, and (c) fixation in osmium tetroxide, posttreatment in uranyl acetate, and dehydration in a graded series of acetone. Preparations were made after each stage in the presence of 20% glycerol. Good preservation of ultrastructure was observed, after any of the three treatments, of the outer surface of the plasma membrane, and the inner surface of the plasma membrane. No alteration in fracturing properties could be observed. However, if we are to judge by the results of freeze-etching, any of the successive steps of the chemical fixation procedure achieve strong contrast between the nucleoplasmic region and the cytoplasm. Dependent on the quality of fixation, very delicately preserved DNA fibrils or strongly aggregated ones were seen. It appears that R-K fixation is capable of producing more or less distinctly visible changes in the native state of the nucleoplasm in young cells of B. subtilis.
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Article| September 01 1969
PRESERVATION OF THE ULTRASTRUCTURE OF BACILLUS SUBTILIS BY CHEMICAL FIXATION AS VERIFIED BY FREEZE-ETCHING
From the Laboratory of Electron Microscopy, the University of Amsterdam, Amsterdam, The Netherlands
Received: February 24 1969
Revision Received: March 28 1969
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1969 by The Rockefeller University Press.
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N. Nanninga; PRESERVATION OF THE ULTRASTRUCTURE OF BACILLUS SUBTILIS BY CHEMICAL FIXATION AS VERIFIED BY FREEZE-ETCHING . J Cell Biol 1 September 1969; 42 (3): 733–744. doi: https://doi.org/10.1083/jcb.42.3.733
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