uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Comparative Genomics of Obligate and Facultative Intracellular Parasites
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology, Molecular Evolution.
2002 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The α-proteobacteria Rickettsia prowazekii and Bartonella henselae are the causative agents of epidemic typhus and cat scratch disease respectively. Whereas R. prowazekii is an obligate intracellular parasite, B. henselae can live and proliferate both outside and inside the eukaryotic host cell. Besides the obvious medical interest to identify the complete gene set of two human pathogens, their genome sequences are also important for the study of evolutionary processes. Both R. prowazekii and B. henselae have small genomes, but their last common ancestor of these two bacteria was most likely a free-living organism with a substantially larger genome.

The aim of this thesis is to compare the complete genomes of R. prowazekii and B. henselae and to decipher the evolutionary processes leading to the adaptation to an intracellular lifestyle. The working hypothesis was that the facultative intracellular B. henselae is an intermediate between a free living bacteria and the obligate R. prowazekii, which is corroborated. B. henselae has a broader biosynthetic repertoire than R. prowazekii, including the presence of genes for glycolysis and de novo biosynthesis of purines and pyrimidines. However, both bacteria have reduced gene sets for biosynthesis of amino acids and cofactors compared to free-living bacteria.

Comparisons of gene order in bacteria reveal that several operons are well conserved between distantly related species. The genome sequences of R. prowazekii and B. henselae show that many of the operons that are usually conserved, are broken and rearranged in these species. One of the mechanisms of reductive evolution include intra-chromosomal recombination between repeated loci. This process expels one of the repeats and cause rearrangements in the gene order of the flanking regions. While the R. prowazekii genome almost completely lack repeated sequences, the B. henselae genome is rich in repeats. These repeats are, however, most often located within regions associated with pathogenicity islands. The higher number of scrambled operons, and the lower number of repeats, in R. prowazekii compared to B. henselae imply that the reductive process has gone further in the former species.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 2002. , 52 p.
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 731
Keyword [en]
Developmental biology
Keyword [sv]
Utvecklingsbiologi
National Category
Developmental Biology
Research subject
Molecular Biology
Identifiers
URN: urn:nbn:se:uu:diva-2154ISBN: 91-554-5353-8 (print)OAI: oai:DiVA.org:uu-2154DiVA: diva2:161810
Public defence
2002-06-07, Lindahlssalen (05:01058), EBC, Uppsala, 13:15
Opponent
Available from: 2002-05-17 Created: 2002-05-17Bibliographically approved

Open Access in DiVA

No full text
Buy this publication >>

By organisation
Molecular Evolution
Developmental Biology

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 482 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf