Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potential perinatal pathogens. Their relationships between genotypes and pathogenesis of GBS and ureaplasma infection were still not well understood, one of the reason is that both of them are still short of a very practical genotyping system. In the study, to solve the above problem we developed genotyping systems for the organisms (the second section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasma species (U. parvum and U. urealyticum). Further, based on the heterogeneity of ureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotyping systems showed that the genotyping systems were practical alternative assays for the conventional serotyping and they will be useful to further explore the relationships between genotypes and pathogenesis of GBS and ureaplasma infection. In the study, we introduced novel data and tools into GBS and ureaplasma studies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based on the U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied the two published full genomes and exposed some new problems or possible future new research fields. In particular we found the two finished and one ongoing GBS genomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integrated studies of the two potential or conditional perinatal pathogens, from the viewpoint of evolution, would provide a new understanding angle of the pathogenesis of the two organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host (by losing most of its virulence genes); however, GBS tried to increase its invasive abilities (by getting more virulence genes) to fight against the human host attack.
| Identifer | oai:union.ndltd.org:ADTP/283018 |
| Date | January 2004 |
| Creators | Kong, Fanrong |
| Publisher | University of Sydney. Medicine |
| Source Sets | Australiasian Digital Theses Program |
| Language | English, en_AU |
| Detected Language | English |
| Rights | Copyright Kong, Fanrong;http://www.library.usyd.edu.au/copyright.html |
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