Abstract
Opaque colony variants of two strains of group A streptococci have been compared with blue colonies of the same strains by electron microscopy. In opaque colonies, the cocci are joined into elongated chains by exaggerated intercellular septa that often occupy the major portion of each cell's circumference. The thickness and lamination of cell walls in opaque colony variants are identical to those aspects of cell walls in blue colony forms. The similarity in cell wall architecture is found between opaque and blue forms whether or not M protein (and M associated surface fimbriae) is present. Extensive, direct contact between the nucleoid and the cytoplasmic membrane beneath intercellular septa is seen in opaque colony variants. The relationship of this marked nucleoid-cytoplasmic membrane association to the unusual chain forms in the opaque colony variants is unclear.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- KELLENBERGER E., RYTER A., SECHAUD J. Electron microscope study of DNA-containing plasms. II. Vegetative and mature phage DNA as compared with normal bacterial nucleoids in different physiological states. J Biophys Biochem Cytol. 1958 Nov 25;4(6):671–678. doi: 10.1083/jcb.4.6.671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCarty M. The nature of the opaque colony variation in group A streptococci. J Hyg (Lond) 1966 Jun;64(2):185–190. doi: 10.1017/s0022172400040444. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ryter A. Association of the nucleus and the membrane of bacteria: a morphological study. Bacteriol Rev. 1968 Mar;32(1):39–54. doi: 10.1128/br.32.1.39-54.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- VENABLE J. H., COGGESHALL R. A SIMPLIFIED LEAD CITRATE STAIN FOR USE IN ELECTRON MICROSCOPY. J Cell Biol. 1965 May;25:407–408. doi: 10.1083/jcb.25.2.407. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WILSON A. T. The relative importance of the capsule and the M-antigen in determining colony form of group A streptococci. J Exp Med. 1959 Mar 1;109(3):257–270. doi: 10.1084/jem.109.3.257. [DOI] [PMC free article] [PubMed] [Google Scholar]