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Regulation of capsule biosynthesis in Streptococcus pneumoniae (and related pathogenic streptococci) by environmental factors and transcription regulators

Kol, K.J. (2009) Regulation of capsule biosynthesis in Streptococcus pneumoniae (and related pathogenic streptococci) by environmental factors and transcription regulators. Bachelor's Thesis, Biology.

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Abstract

Streptococcus pneumoniae (also known as pneumococcus) is a gram positive human pathogen that causes local infections and serious life-threatening diseases. S. pneumoniae produces capsular polysaccharides that are crucial for systemic virulence. The capsule also protects the bacteria from opsonophagocytosis after invasion. The biosynthesis of the capsule is mainly regulated by the cps locus. Two-component systems (TCS), other transcriptional regulators and environmental factors play roles in the regulation of the capsule expression. The orphan two-component signal transduction response regulator RitR plays a very important role in the regulation of capsule biosynthesis. RitR downregulates the ugd gene which is required for the synthesis of the S. pneumoniae type 3 capsule. The environmental factors Mg2+ and antimicrobial peptide LL-37 could have an effect on this system. Another two-component system involved in the capsule biosynthesis is SivS/R. A ∆siv mutant of Streptococcus iniae transcribed two-thirds less cpsA (the first gene of the capsule operon of S. iniae). There is also a transcription factor that has an effect on capsule biosynthesis, called RegM. A regM mutant showed a significantly decreased expression of the cps locus. Besides the environmental factors Mg2+ and human antimicrobial peptide LL-37, environmental factors such as sugar source and availability, oxygen, iron and environmental conditions in biofilms also play important roles. Most of the environmental factors and transcriptional regulators described had a significant and strong effect on the expression of capsule genes and capsule. The underlying mechanisms are very complex and there is still little known about these mechanisms. Further studies are still needed to find out if all of the environmental factors mentioned above have an effect on the capsule biosynthesis in S. pneumoniae.

Item Type: Thesis (Bachelor's Thesis)
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: http://fse.studenttheses.ub.rug.nl/id/eprint/8580

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