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Ribosome‐like Particles in the Spherical Body of an Oral Treponeme
Author(s) -
Umemoto Toshihiko
Publication year - 1980
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.1348-0421.1980.tb02837.x
Subject(s) - ribosome , physics , chemistry , rna , biochemistry , gene
Electron microscopical studies of spirochetes, such as Leptospira, Treponema, and Borellia, have revealed that these organisms consist of an outer envelope (OE), axial fibrils (AF), and a main body (MB). Some investigators demonstrated granules in the cytoplasm of the MB by ultrathin sectioning and stated that those granules were ribosomes (5, 9, 10). The particles they called ribosomes, however, could not be seen clearly, had a rough distribution and were not definitely identified. They were called ribosomes simply because of a morphological resemblance to bacterial ribosomes. The author previously reported that oral treponemes grown in a medium containing 8-10% sucrose produced many spherical bodies (SB) which were recognized as the result of expansion of the OE and coiling of the MB (14, 15). This paper describes some characteristics of ribosome-like particles (R1P) observed in the MB of treponemal SB. An oral treponeme, strain G7201, was grown in sterility test broth containing either no sucrose or 9.3% sucrose as previously reported (14). The cells were fixed for 1 hr in cacodylate-buffered 2% glutaraldehyde (pH 7.2) and then suspended for 3 hr in the buffer containing 0.05% ruthenium red (RR). The rinsed pellets were post-fixed for 3 hr in buffered 1 % osmium tetroxide, rinsed, dehydrated in ethanol, and embedded in Epon 812, by the method described by Luft (7) . Ultrathin sections were cut with an LKB 8800A-NM ultrotome. The sections were stained successively with uranyl acetate and lead citrate (11), and examined under a JEM-100B electron microscope at 80 kV. An ultrathin section of SB showed that the MB was crowded with R1P (Fig. 1). Some SB had largely swollen MB and their wall-membrane complex (WMC) was partially damaged (Fig. 2). The diameter of the R1P was approximately 27 nm and their dense distribution was observed both inside and outside of the MB. The particles released from the broken MB were mostly uniform in size and attached to the surface of the MB, the AF, and the inner layer of the OE (Fig. 3). R1P showed a clear image in the RR-stained preparation. This phenomenon was clearly recognized by the scattered R1P in the SB with a damaged WMC. A mass of the particles was slipping out from the broken MB (Fig. 3, arrow). A regular array of R 1 P was also seen in most sections of the swollen MB, and the