#Twitch leecher inconsistant frames Activator#

The cells smoothly moved over solid surfaces towards green light, but the direction was switched to backward movement when we applied additional blue light illumination. Positive and negative phototaxis were controlled on a short time scale of 1 min. Here, we visualized type IV pilus-dependent cell movement in the rod-shaped thermophilic cyanobacterium Thermosynechococcus vulcanus using optical microscopy at physiological temperature and light conditions. However, the molecular and cell biological mechanisms for switching the direction of movement remain unclear. Many cyanobacteria, which use light as an energy source via photosynthesis, show directional movement towards or away from a light source. Black bars represent (vertical) mean and (horizontal) SD across biological replicates. Circles represent the median of each biological replicate. ΔpilH has higher symmetry index than WT and ΔcpdA. The values 0.5 and 1 respectively correspond to a symmetric bipolar and a unipolar localization. (F and H) Symmetry index of PilB-mNG and mNG-FimX, respectively, representing the ratio of the brightest pole fluorescence to the total polar fluorescence. Relative to WT and ΔcpdA, polar localization is higher in ΔpilH and lower in in ΔpilG. An index of 0 and 1 respectively correspond to completely diffuse and polar signals. (E and G) Polar localization index of PilB-mNG and mNG-FimX respectively, quantifying the extent of polar signal compared with a diffused configuration (SI Appendix, Fig. The shaded area represents SD across biological replicates. Solid lines represent the mean normalized fluorescence profiles across biological replicates.

#Twitch leecher inconsistant frames Activator#

(Scale bar, 5 μm.) (C and D) Normalized fluorescence profiles along the major cell axis of the motor protein PilB and its activator FimX (SI Appendix, Fig. Snapshots of PilB-mNG (A) and mNG-FimX (B) fluorescence in WT, ΔpilG, ΔpilH, and ΔcpdA background. PilG and PilH control the polarization of T4P extension machinery. Circles correspond the fraction of each biological replicate, and black bars represent their mean. (E) Fraction of cells twitching in the direction of their brightest pole. PilB and FimX signal is more asymmetric in moving cells, which is not the case for PilT and PilU. (D) Comparison of the symmetry of polar fluorescence between moving and nonmoving cells. Black bars correspond to their mean across replicates. Each circle is the mean fraction for one biological replicate. We could not distinguish a T4P depletion at the bright retraction motor poles. Most cells have more T4P at the bright PilB-mNG pole. (Scale bar, 5 μm.) (C) Fraction of cells with more T4P at bright versus dim fluorescent pole. (Scale bars, 5 μm.) (B) Simultaneous imaging of PilB-mNG and T4P by correlative iSCAT fluorescence. (A) Snapshot of chromosomal fluorescent protein fusions to the extension motor PilB, its regulator FimX, and the retraction motors PilT and PilU. The localization of the extension motor PilB sets the direction of twitching and the polarization of T4P activity. (Scale bar, 50 μm.) Background strain: PAO1 ΔfliC. (F) While WT is able to move efficiently at high density, the reduced ability of ΔpilH to reverse upon collision leads to cell jamming and clustering. Circles correspond to biological replicates, and black bars represent their mean. A total of 60% of cells reverse after collision, irrespective of the type of obstacle. (Scale bar, 2 μm.) (E) Fraction of WT cells reversing upon collision with another cell and with a glass microfiber. The dashed lines indicate the position of the fiber. (D) Phase contrast image sequence of WT cells reversing upon collision with glass microfibers and other cells. About half of WT cells reverse after collision, ΔpilH almost never reserves after collision, and ΔpilGcpdA almost always reverses. (Scale bar, 2 μm.) (C) Fraction of cells reversing upon collision with another cell. The red triangle indicates the initial leading pole of the bacterium. The same sequence for a ΔpilH cell, failing to reverse upon collision (Right). (B) Snapshots of WT reversing upon collision with another cell (Left). ΔpilH has a twofold lower reversal frequency than ΔcpdA. ΔpilGcpdA has highest reversal frequency. (A) Quantification of reversal rates in Chp and cAMP mutants. The Chp system controls reversals of twitching P.