Average cytoplasmic ribosome density [MSB=Myojin spiral bacteria, MTB=M. tuberculosis]

Range MSB 220: MTB 720: E. coli 2,840: Exophiala dermatitidis 1,100: S. cerevisiae 1,950 ribosomes/0.1fL cytoplasm
Organism Microbes
Reference Hiroyuki Yamada et al., Structome analysis of Escherichia coli cells by serial ultrathin sectioning reveals the precise cell profiles and the ribosome density, Microscopy, Volume 66, Issue 4, August 2017, Pages 283–294, link p.290 table 6 PubMed ID28854579
Method P.286 left column bottom paragraph: "In this study, E. coli was selected as a target of the structome analysis because a large number of molecular biological studies were performed with this microorganism. E. coli cells were cut into 65 nm thick serial ultrathin sections after rapid cryofixation and freeze-substitution. In addition to the structome analysis by serial ultrathin sectioning, PCM (phase contrast microscopy) and SEM (scanning electron microscopy) examinations were performed on the same bacterial sample because the fundamental morphological studies were achieved with these observation techniques." P.285 right column 2nd paragraph: "Ribosomes as electron dense particles with 20 nm diameter in the cytoplasm of the cell in each serial ultrathin section were enumerated [refs 16,22] using menus and macro of ImageJ/ Fiji [ref 21]."
Comments P.288 right column, top paragraph: "In this report, as well as [investigators'] previous studies, ribosome enumeration was performed by direct counting ribosomes as 20 nm electron dense particles on the electron micrographs of the nine cells (Table 5). Average total ribosome number of the nine cells was 26 100 ± 4020 (ranging from 21 800 to 36 600), where the individual number may deviate depend on the volume of the cytoplasm. Therefore, the average ribosome density per 0.1 fl cytoplasm was calculated and it was 2840 ± 120 (ranging from 2600 to 2970), which was independent of the whole cytoplasmic volume of each cell and the deviation was very small. Comparison of these data between Myojin spiral bacteria, MTB, E. coli, and two yeast species (E. dermatitidis and S. cerevisiae) was performed (Table 6). In total ribosome number, the cells of two yeast species, E. dermatitidis and S. cerevisiae had significantly higher number, ~195 000 per cell compared to E. coli cells, ~26 100, (both P < 0.0001). It stands to reason that the larger the cytoplasm volume is, the more ribosomes are contained. On the other hand, in ribosome density per 0.1 fl, E. coli cells showed significantly higher density as ~2840 per 0.1 fl cytoplasm compared to Myojin spiral bacteria (220 per 0.1 fl cytoplasm, P < 0.0001), MTB (720 per 0.1 fl cytoplasm, P < 0.0001), E. dermatitidis (1100 per 0.1 fl cytoplasm, P < 0.0001) and S. cerevisiae (1950 per 0.1 fl cytoplasm, P < 0.0001)." femto-liter (fl)=μm^3=10^-15L
Entered by Ron Milo - Admin
ID 117349