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Electron Microscopic Demonstration and Isolation of Ribosomes in Mesosomes from Staphylococcus aureus
Author(s) -
Nakasone Noboru,
Kawata Tomio,
Masuda Kuniyoshi
Publication year - 1987
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1987.tb03066.x
Subject(s) - differential centrifugation , ribosome , centrifugation , electron microscope , biophysics , biology , protoplast , cytoplasm , tubule , density gradient , tonicity , staphylococcus aureus , biochemistry , rna , bacteria , physics , genetics , optics , gene , kidney , endocrinology , quantum mechanics
Mesosomes of Staphylococcus aureus 209P were observed to be extruded as tubules upon protoplast formation by electron microscopy and isolated under hypertonic conditions to maintain their structural integrity by differential centrifugation followed by sucrose density gradient centrifugation. Isolated mesosomes were composed of long, branched tubules of irregular sizes and they were shortened during purification. Thin sections of isolated mesosomes showed that the mesosomal tubule was surrounded by a triple‐layered membrane and contained ribosome‐like particles in diameter of about 15 to 20 nm. These particles were isolated from purified mesosomal preparation by disrupting the mesosomal tubule with deoxycholate and Triton X‐100 under hypotonic conditions followed by a linear sucrose density gradient centrifugation. Negatively stained preparations of the isolated particles revealed the same appearance as those of the ribosomes isolated from the cytoplasm. The mesosomal particles sedimented at 70S in sucrose gradients in the presence of 10 mm Mg 2+ , but they were dissociated into two subparticles, 50S and 30S subunits, upon lowering the Mg 2+ concentration to 1 mm. These findings indicate that the mesosomal tubule is packed with ribosomes.