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Title: The biological activity of Bacteroides surface polysaccharides
Author: Delahooke, Diane Mary
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1996
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Lipopolysaccharide (LPS), a major constituent of Gram-negative bacteria, is implicated as the key factor in the development of the Systemic Inflammatory Response Syndrome (SIRS). LPS can arise from an underlying bacteraemia, but given that the majority of patients with SIRS have no detectable bacteraemia, then LPS derived from the gut must be considered. Bacteroides species outnumber the enterobacteria such as E.coli in the gut by approximately 1000-fold. Although Bacteroides LPS is less endotoxic, by simple arithmetic there must be as much biological potential from the LPS of Bacteroides as from E.coli. This thesis re-examines the biological activity of Bacteroides LPS and its possible role in the development of SIRS. LPSs were extracted from seven Bacteroides species by three different techniques: the phenol-water (PW), the phenol-chloroform-petroleum (PCP) and Triton-Mg2+. The biological activity of these Bacteroides LPSs was compared to that of an E.coli O18K- LPS control. In general, Bacteroides LPSs prepared by the PW method were found to have a significantly higher activity in a mouse lethality model, LAL assay, TNF and IL-8 induction assays, than LPS extracted by the PCP or Triton methods. Bacteroides LPS extracted by the PCP method had consistently low activity in all assays. LPS from B.fragilis NCTC 9343 and B.caccae had a consistently higher activity than LPS from B.vulgatus and B.thetaiotaomicron in most assays. Differences in activity between B.fragilis NCTC 9343 LPS grown in different media was seen. The PW method selected for greater amounts of carbohydrate and KDO and the PCP the least. Further information from sub-population studies, Percoll profiles, chemotype on PAGE and chemical analysis failed to account for differences in biological activity between extraction methods and Bacteroides species.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available