Abstract
Study of the capsular genome of pneumococcus has shown that it controls a multiplicity of biochemical reactions essential to the synthesis of capsular polysaccharide. Mutation affecting any one of several biochemical reactions concerned with capsular synthesis may result in loss of capsulation without alteration of other biochemical functions similarly concerned. Mutations affecting the synthesis of uronic acids are an important cause of loss of capsulation and of virulence by strains of pneumococcus Type I and Type III. The capsular genome appears to have a specific location in the total genome of the cell, this locus being occupied by the capsular genome of whatever capsular type is expressed by the cell. Transformation of capsulated or of non-capsulated pneumococci to heterologous capsular type results probably from a genetic exchange followed by the development of a new biosynthetic pathway in the transformed cell. The new capsular genome is transferred to the transformed cell as a single particle of DNA. Binary capsulation results from the simultaneous presence within the pneumococcal cell of two capsular genomes, one mutated, the other normal. Interaction between the biochemical pathways controlled by the two capsular genomes leads to augmentation of the phenotypic expression of the product controlled by one and to partial suppression of the product determined by the other. Knowledge of the biochemical basis of binary capsulation can be used to indicate the presence of uronic acid in the capsular polysaccharide of a pneurnococcal type the composition of the capsule of which is unknown.
Full Text
The Full Text of this article is available as a PDF (1.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- AUSTRIAN R., BERNHEIMER H. P. Simultaneous production of two capsular polysaccharides by pneumococcus. I. Properties of a pneumococcus manifesting binary capsulation. J Exp Med. 1959 Oct 1;110:571–584. doi: 10.1084/jem.110.4.571. [DOI] [PMC free article] [PubMed] [Google Scholar]
- AUSTRIAN R. Observations on the possible role of nucleic acid exchange reactions in pneumococcal capsular type transformation; a preliminary note. Bull Johns Hopkins Hosp. 1952 Feb;90(2):170–174. [PubMed] [Google Scholar]
- BRINK R. A. Paramutation at the R locus in maize. Cold Spring Harb Symp Quant Biol. 1958;23:379–391. doi: 10.1101/sqb.1958.023.01.036. [DOI] [PubMed] [Google Scholar]
- CORDOBA F., HEIDELBERGER M. Cross-reactions of antityphoid and antiparatyphoid B horse sera with various polysaccharides. J Exp Med. 1956 Sep 1;104(3):375–382. doi: 10.1084/jem.104.3.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heidelberger M., Kendall F. E., Scherp H. W. THE SPECIFIC POLYSACCHARIDES OF TYPES I, II, AND III PNEUMOCOCCUS : A REVISION OF METHODS AND DATA. J Exp Med. 1936 Sep 30;64(4):559–572. doi: 10.1084/jem.64.4.559. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KALCKAR H. M., MAXWELL E. S. Biosynthesis and metabolic function of uridine diphosphoglucose in mammalian organisms and its relevance to certain inborn errors. Physiol Rev. 1958 Jan;38(1):77–90. doi: 10.1152/physrev.1958.38.1.77. [DOI] [PubMed] [Google Scholar]
- LEIDY G., HAHN E., ALEXANDER H. E. In vitro production of new types of hemophilus influenzae. J Exp Med. 1953 Apr;97(4):467–482. doi: 10.1084/jem.97.4.467. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MACLEOD C. M., KRAUSS M. R. Transformation reactions with two non-allelic R mutants of the same strain of Pneumococcus type VIII. J Exp Med. 1956 May 1;103(5):623–632. doi: 10.1084/jem.103.5.623. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Macleod C. M., Krauss M. R. STEPWISE INTRATYPE TRANSFORMATION OF PNEUMOCOCCUS FROM R TO S BY WAY OF A VARIANT INTERMEDIATE IN CAPSULAR POLYSACCHARIDE PRODUCTION. J Exp Med. 1947 Nov 30;86(6):439–452. doi: 10.1084/jem.86.6.439. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SMITH E. E., MILLS G. T., BERNHEIMER H. P., AUSTRIAN R. A study of some enzymes in extracts of a non-capsulated strain of pneumococcus concerned with uridine pyrophosphoglycosyl metabolism. J Gen Microbiol. 1959 Jun;20(3):654–669. doi: 10.1099/00221287-20-3-654. [DOI] [PubMed] [Google Scholar]
- SMITH E. E., MILLS G. T., BERNHEIMER H. P., AUSTRIAN R. The presence of an uronic acid epimerase in a strain of pneumococcus type I. Biochim Biophys Acta. 1958 Sep;29(3):640–641. doi: 10.1016/0006-3002(58)90023-4. [DOI] [PubMed] [Google Scholar]
- SMITH E. E., MILLS G. T., HARPER E. M. A comparison of the uridine pyrophosphoglycosyl metabolism of capsulated and non-capsulated pneumococci. J Gen Microbiol. 1957 Apr;16(2):426–437. doi: 10.1099/00221287-16-2-426. [DOI] [PubMed] [Google Scholar]
- SMITH E. E., MILLS G. T., HARPER E. M., GALLOWAY B. The cellular polysaccharide of a type II non-capsulated Pneumococcus. J Gen Microbiol. 1957 Oct;17(2):437–444. doi: 10.1099/00221287-17-2-437. [DOI] [PubMed] [Google Scholar]
- SMITH E. E., MILLS G. T., HARPER E. M. The isolation of uridine pyrophosphogalacturonic acid from a type I penumococcus. Biochim Biophys Acta. 1957 Mar;23(3):662–663. doi: 10.1016/0006-3002(57)90400-6. [DOI] [PubMed] [Google Scholar]
- TAYLOR H. E. Additive effects of certain transforming agents from some variants of pneumococcus. J Exp Med. 1949 Apr 1;89(4):399–424. doi: 10.1084/jem.89.4.399. [DOI] [PMC free article] [PubMed] [Google Scholar]