A biochemical and immunological investigation of the extracellular polysaccharides produced from sugars by the oral streptococci

Massam, F., 1985. A biochemical and immunological investigation of the extracellular polysaccharides produced from sugars by the oral streptococci. PhD, Nottingham Trent University.

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The development of a method for the measurement of cell-associated extracellular polysaccharides produced by five species of oral streptococci indicated quantitative differences, in polysaccharide synthesis. S. mutans, S. sanguis and S. salivarius produced extracellular polysaccharides (EPS) from sucrose but not from other sugars nor from an aquimolar mixture of glucose and fructose. Cells of S. mitior and S. milleri produced EPS from none of the sugars investigated. Maltose was shown to act as a pre-cursor for the synthesis of large amounts of intracellular iodophilic polysaccharide by S. mutans.

The EPS produced by sucrose-grown cells of S. mutans, S. sanguis and S. salivarius was shown to be synthesised during the logarithmic phase of growth, but was rapidly degraded after cells entered the stationary phase. These polysaccharides were predominantly 1-6 and 1-3 linked glucose homopolymers, and the relative proportions of these linkages varied between species. The glucans produced by S. mutans and S. salivarius. showed evidence of a branched structure, whereas those produced by S. sanguis exhibited a "dextrin"-like structure of short, linear 1-6 glucosidic linkages with no evidence of branching.

Agglutination studies performed on mouse sera indicated that glucan- coated cells of S. mutans and S. sanguis elicited a lower antibody response to cell-wall determinants than did those lacking cell- associated glucans. The relevance of these data is discussed in terms of the aetiology of streptococcal endocarditis. An Enzyme-Linked Immunosorbent Assay was developed for the quantification of the antibody response of mice to the EPS of oral streptococci. Data 'are presented which indicate the quantity, specificity and class of this antibody response. The potential application of an immunological approach to the elucidation of the structure and composition of streptococcal glucans is discussed.

Item Type: Thesis
Creators: Massam, F.
Date: 1985
ISBN: 9781369325812
Divisions: Schools > School of Science and Technology
Record created by: Laura Ward
Date Added: 08 Jul 2021 10:05
Last Modified: 22 May 2024 15:09
URI: https://irep.ntu.ac.uk/id/eprint/43380

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