Characterization of motility and piliation in pathogenic Neisseria.
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 μm/s, whereas N. gonorrhoeae moved with a lower speed (1.0 μm/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.
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. jenseri@gmail.com.
Jens
J
Eriksson
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. olaspers@gmail.com.
Olaspers Sara
OS
Eriksson
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. maudsdotter@gmail.com.
Lisa
L
Maudsdotter
Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden. opalm@kth.se.
Oskar
O
Palm
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. jakob.engman@su.se.
Jakob
J
Engman
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. tim.sarkissian@gmail.com.
Tim
T
Sarkissian
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. HelenaAro@gmail.com.
Helena
H
Aro
Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden. wallin@kth.se.
Mats
M
Wallin
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden. ann-beth.jonsson@su.se.
Ann-Beth
AB
Jonsson
D001483:Base Sequence; D017124:Conserved Sequence; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000502:physiology*; D009345:Neisseria meningitidis / Q000502:physiology*; D011401:Promoter Regions, Genetic; D013045:Species Specificity
D036781:Fimbriae Proteins