Bacteria can travel long distances thanks to flagellar appendages that allow them to move. When a motile bacterium approaches a surface, it undergoes hydrodynamic interactions that result in a directed circular motion of its trajectory that confines it to the surface. However, the trajectory of a bacterium is marked by reorientations and stops that are the result of a change in the direction of rotation of the bundle of flagella. This change of direction occurs periodically, about every 1s, for 100ms for the bacterium E. coli. The random reorientation of the bacteria near a surface allows the trapped bacteria to abruptly extract to the volume and reorient to explore their environment.
Bacterial chemotaxis, which takes advantage of a frequency bias in reorientation, allows the redistribution of a bacterial population. We study the effects of known chemorepellent and chemoattractant substances such as Ni2+ and Mg2+ cations, on bacterial redistribution. For this purpose, we conduct experiments in dark field video microscopy by varying the sources of chemical agents in microfluidic channels
Here, I will describe a protocol to apply dark-field video microscopy and post-processing of the bacterial tracks to decipher the main physico-chemical laws that prevail between an individual bacterium and the reactive surface will be specified. This work should also establish a documented reference of the collective behavior of a population of bacteria near reactive surfaces.
| Subject : | : | poster (no slots available) |
| Topics | : | Geology |
| PDF version | : |  PDF version |
