Dik, J.W. (2009) Carbon metabolism and synthesis of the polysaccharide capsule of Streptococcus pneumoniae and related pathogenic streptococci. Bachelor's Thesis, Biology.
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Abstract
Streptococcus pneumoniae is a gram-positive humane pathogen which can cause respiratory and invasive diseases with a high morbidity and mortality. The polysaccharide synthesis and the carbon metabolism of S. pneumonaie are reviewed here. The production of the capsule is mediated by the so-called Wzy-dependent pathway. Only in serotypes 3 and 37, the CPS synthesis is different. Within the capsular polysaccharide biosynthesis locus there is a high diversity in 91 different serotypes. Only the first four genes, cpsA-D, are common to almost all of the serotypes, but following these are the serotype specific genes. The capsule synthesis seems to be transcriptional regulated upon adherence by down regulation of first gene, cpsA. In the nasopharynx and lungs, were glucose is low, capsule expression may well be regulated at a post-transcriptional level, which involves the auto-phosphorylation of CpsD. For its survival, sugars are essential. By means of four exoglycosidases NanA, NanB, BgaA and StrH, it is capable of enzymatic degradation of host glycoproteins. A regulatory link between the carbon metabolism and capsule synthesis, maybe CcpA. This protein is known to be a regulator in the carbon control repression (CCR) and enables the bacteria to utilize the preferred sugars. This review is the first to suggest the regulator role of cpsA during adherence and thereby playing a role in the diminished capsule expression. The links between the capsule and the carbon metabolism are still unclear, but even though CcpA plays a role it is not the sole regulator.
| Item Type: | Thesis (Bachelor's Thesis) |
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| Degree programme: | Biology |
| Thesis type: | Bachelor's Thesis |
| Language: | English |
| Date Deposited: | 15 Feb 2018 07:28 |
| Last Modified: | 15 Feb 2018 07:28 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/8570 |
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