Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms

dc.contributor.advisorStephen, Marquard
dc.contributor.authorMerrifield, Edwin Howard
dc.date.accessioned2023-10-02T09:40:01Z
dc.date.available2023-10-02T09:40:01Z
dc.date.issued1978
dc.date.updated2023-10-02T09:18:34Z
dc.description.abstractThe structures of the exopolysaccharides from a number of strafos of the bacterial genus KlebsieUa have been investigated and compared. ·All of these polysaccharides have been shown to be composed of regularly repeated oligosaccharide units containing -glucuronic acid and three to five hexose residues, with pyruvic acid ketal and 0-acetyl groups also present in some of the polysaccharides. Graded acid hydrolysis, monitored by gel-permeation chromato graphy, has been used to study the degradation of each polysaccharide to the structurally significant oligosaccharides and fragments of higher molecular weight which are clearly aggregates of these units. In all cases both acidic and neutral oligosaccharides have been isolated in a high degree of purity, which has permitted their characterisation by standard techniques, including partial acid hydrolysis and methylation analysis, and the use of proton magnetic resonance spectroscopy and measurement of optical rotatory power to determine the nature of anomeric linkages. The polysaccharides from Klebsiella K4 and X.pnev.moniae ( oxytoca variant) have been shovm to have linear tetra- and pentasaccharide repeating units respectively, while the structures of those from serotypes K27 and K64 have been found to be more complex, consisting of branched hexasaccharide repeating units with pyruvic acid ketallinked to one sugar residue. In addition, the fungal polysaccharides from two strains of c1yptococcus neoformans have been investigated and shovm to be chemically equivalent. The evidence obtained from partial acid hydrolysis, methylation analysis and Smith-degradation studies performed on one of these polysaccharides is consistent with a structure in which a linear (l-+3)- linked chain of -mannose residues is substituted at position C-2 by either g-glucuronic acid or ll_-xylose. This represents one of the few complete characterisations of a Cryptococcus polysaccharide to be achieved up to the present.
dc.identifier.apacitationMerrifield, E. H. (1978). <i>Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms</i>. (). ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/39002en_ZA
dc.identifier.chicagocitationMerrifield, Edwin Howard. <i>"Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms."</i> ., ,Faculty of Science ,Department of Chemistry, 1978. http://hdl.handle.net/11427/39002en_ZA
dc.identifier.citationMerrifield, E.H. 1978. Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms. . ,Faculty of Science ,Department of Chemistry. http://hdl.handle.net/11427/39002en_ZA
dc.identifier.risTY - Doctoral Thesis AU - Merrifield, Edwin Howard AB - The structures of the exopolysaccharides from a number of strafos of the bacterial genus KlebsieUa have been investigated and compared. ·All of these polysaccharides have been shown to be composed of regularly repeated oligosaccharide units containing -glucuronic acid and three to five hexose residues, with pyruvic acid ketal and 0-acetyl groups also present in some of the polysaccharides. Graded acid hydrolysis, monitored by gel-permeation chromato graphy, has been used to study the degradation of each polysaccharide to the structurally significant oligosaccharides and fragments of higher molecular weight which are clearly aggregates of these units. In all cases both acidic and neutral oligosaccharides have been isolated in a high degree of purity, which has permitted their characterisation by standard techniques, including partial acid hydrolysis and methylation analysis, and the use of proton magnetic resonance spectroscopy and measurement of optical rotatory power to determine the nature of anomeric linkages. The polysaccharides from Klebsiella K4 and X.pnev.moniae ( oxytoca variant) have been shovm to have linear tetra- and pentasaccharide repeating units respectively, while the structures of those from serotypes K27 and K64 have been found to be more complex, consisting of branched hexasaccharide repeating units with pyruvic acid ketallinked to one sugar residue. In addition, the fungal polysaccharides from two strains of c1yptococcus neoformans have been investigated and shovm to be chemically equivalent. The evidence obtained from partial acid hydrolysis, methylation analysis and Smith-degradation studies performed on one of these polysaccharides is consistent with a structure in which a linear (l-+3)- linked chain of -mannose residues is substituted at position C-2 by either g-glucuronic acid or ll_-xylose. This represents one of the few complete characterisations of a Cryptococcus polysaccharide to be achieved up to the present. DA - 1978 DB - OpenUCT DP - University of Cape Town KW - Neoformans micro-organisms LK - https://open.uct.ac.za PY - 1978 T1 - ETD: Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms TI - ETD: Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms UR - http://hdl.handle.net/11427/39002 ER -en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/39002
dc.identifier.vancouvercitationMerrifield EH. Structural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms. []. ,Faculty of Science ,Department of Chemistry, 1978 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/39002en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Chemistry
dc.publisher.facultyFaculty of Science
dc.subjectNeoformans micro-organisms
dc.titleStructural studies of the capsular polysaccharides from some strains of Klebsiella and Cryptococcus neoformans micro-organisms
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationlevelPhD
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