| 1. |
- Eriksson, Jens, et al.
(författare)
-
Characterization of motility and piliation in pathogenic Neisseria
- 2015
-
Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The type IV pili (Tfp) of pathogenic Neisseria (i. e., N. gonorrhoeae and N. meningitidis) are essential for twitching motility. Tfp retraction, which is dependent on the ATPase PilT, generates the forces that move bacteria over surfaces. Neisseria motility has mainly been studied in N. gonorrhoeae whereas the motility of N. meningitidis has not yet been characterized. Results: In this work, we analyzed bacterial motility and monitored Tfp retraction using live- cell imaging of freely moving bacteria. We observed that N. meningitidis moved over surfaces at an approximate speed of 1.6 mu m/s, whereas N. gonorrhoeae moved with a lower speed (1.0 mu/s). An alignment of the meningococcal and gonococcal pilT promoters revealed a conserved single base pair variation in the -10 promoter element that influence PilT expression. By tracking mutants with altered pilT expression or pilE sequence, we concluded that the difference in motility speed was independent of both. Live-cell imaging using total internal reflection fluorescence microscopy demonstrated that N. gonorrhoeae more often moved with fewer visible retracting filaments when compared to N. meningitidis. Correspondingly, meningococci also displayed a higher level of piliation in transmission electron microscopy. Nevertheless, motile gonococci that had the same number of filaments as N. meningitidis still moved with a lower speed. Conclusions: These data reveal differences in both speed and piliation between the pathogenic Neisseria species during twitching motility, suggesting a difference in Tfp-dynamics.
|
|
| 2. |
|
|
| 3. |
- Eriksson, Jens, 1980-, et al.
(författare)
-
Difference in twitching motility between Neisseria meningitidis and Neisseria gonorrhoeae and its relation to pilus dynamics
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 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.
|
|
