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Difference in twitching motility between Neisseria meningitidis and Neisseria gonorrhoeae and its relation to pilus dynamics
Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology. (Ann-Beth Jonsson)
Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology. (Ann-Beth Jonsson)
KTH. (Mats Wallin)
Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology. (Ann-Beth Jonsson)
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Type IV pili of pathogenic Neisseria, i. e. Neisseria gonorrhoeae and Neisseria meningitidis, are essential for initial attachment to host cells, induction of signal transduction cascades and disease development. A characteristic feature of type IV pili is their ability to retract, which generates forces that move bacteria over surfaces. However, the relation between bacterial motility and pilus dynamics remains poorly understood. In this work we analyzed bacterial motility and monitored movement of fluorescently labeled pili by live cell imaging. We found that movement of N. meningitidis occurred at higher speed and with a larger number of retracting pili than for N. gonorrhoeae. Analysis of time-lapse images suggested that N. gonorrhoeae most often moved using one retracting pilus, whereas N. meningitidis most often used four pili. There were no differences in the membrane distribution of PilT among strains. However, we found significantly higher levels of PilT in N. gonorrhoeae than in N. meningitidis. This produces a higher retraction probability, which could contribute to explaining the lower number of pili observed in N. gonorrhoeae. Finally, we propose a mechanism for how the speed of bacterial movement on a surface depends on the number of retracting pili.

Keyword [en]
Type IV pili, twitching motility, PilT, Neisseria
National Category
Microbiology
Research subject
Biophysics; Microbiology
Identifiers
URN: urn:nbn:se:su:diva-65804OAI: oai:DiVA.org:su-65804DiVA: diva2:464839
Available from: 2011-12-14 Created: 2011-12-14 Last updated: 2011-12-14Bibliographically approved
In thesis
1. Virulence Factors and Motility Mechanisms of Pathogenic Neisseria
Open this publication in new window or tab >>Virulence Factors and Motility Mechanisms of Pathogenic Neisseria
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Neisseria gonorrhoeae and Neisseria meningitidis are two closely related human specific pathogens. Neisseria gonorrhoeae is the causative agent for the sexually transmitted disease gonorrhea and often causes asymptomatic infections in women which is a cause of infertility. Neisseria meningitidis is a major cause of mortality world-wide through bacterial meningitis and septicemia. The severity of meningococcal disease, especially in sub-Saharan Africa warrants development of effective vaccines against serogroups that currently lack them. Here, Neisseria host-pathogen interactions and common virulence factors that may prove useful in vaccine development and in understanding disease caused by pathogenic Neisseria are reviewed and investigated. The aim of this thesis is to investigate the virulence-associated properties of the universally expressed N. meningitidis proteins NhhA, NafA, PilU and PilT, as well as to characterize the twitching motility of the pathogenic Neisseria. The conserved autotransporter adhesin NhhA has in Paper I of this thesis been investigated in a murine model of meningococcemia and found to be important for intranasal colonization and disease outcome of N. meningitidis in CD46 transgenic mice. NafA has in Paper II of this thesis been named and identified as a novel anti-aggregation factor that impacts both pilus bundling and the virulence potential of N. meningitidis. The ATPases, PilU and PilT, which are involved in the functionality of pili were studied in Paper III of this thesis. PilU and PilT were found to modulate Neisseria microcolony formation, host cell adhesion, pilus retraction, serum resistance, as well as mortality in a mouse model of meningococcal disease. Finally, Paper IV of this thesis also provides novel insights into the nature of twitching motility in pathogenic Neisseria. By live-cell microscopy and automated particle tracking coupled with visualization of pili in motile bacteria we found that N. meningitidis strains, on average, move faster and utilizes more pili then N. gonorrhoeae. In summary, this thesis investigates Neisseria virulence factors in general, type IV pili in particular and characterizes the roles of several virulence-associated proteins and twitching motility in the pathogenic Neisseria.

Place, publisher, year, edition, pages
Stockholm: Department of Genetics, Microbiology and Toxicology, Stockholm University, 2012. 61 p.
Keyword
Neisseria, Virulence factors, Type IV pili, PilT, PilU, NafA, NhhA, Twitching motility
National Category
Microbiology
Research subject
Molecular Genetics
Identifiers
urn:nbn:se:su:diva-65812 (URN)978-91-7447-423-7 (ISBN)
Public defence
2012-01-27, sal G, Arrheniuslaboratorierna, Svante Arrhenius väg 20 C, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Available from: 2012-01-04 Created: 2011-12-14 Last updated: 2014-10-31Bibliographically approved

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