Although the ability of Act or Chi to alter the instant velocities of individual cells was clear in our analysis, we resorted to statistical methods of random motion particle tracking to provide an objective measurement of the differences in cell motility between the different stimulation conditions.
Thus, we hypothesized that the organization of VASP would indicate biophysical and biochemical differences between different motility modules.
One limitation of these previous studies was the use of heat-killed bacteria or laboratory strains with diminished virulence to control for motility or cytotoxicity differences between different P. aeruginosa strains and mutants, an experimental approach that precluded our ability to identify factors secreted by virulent live cells, such as 3O-C12.
Brabek et al. [ 4] review in this special issue the role of matrix stiffness and composition for plasticity of cancer cell motility, while Parri and Chiarugi [ 5] focus on the role of Rho GTPases for the ad hoc switch between different motility strategies.
Thus, by shifting between different motility styles, migrating cells can adapt to environmental changes and matrix stiffness to elude anticancer treatments, which represents a major challenge for developing strategies aimed at blocking the dissemination of cancer cells [ 1- 3].
Here we further dissect the whole-genome transcriptomic profile of P. aeruginosa swarming motility by comparing gene expression between different bacterial populations localized: 1) at the tip of migrating swarming tendrils, 2) at the center of a swarming colony, and 3) cultured in exactly the same growth conditions except for a harder surface not allowing this type of motility, as control.
Interestingly, the dynamics of the filopodial-rich neuronal growth cone [29] were recently found to exhibit an exponential dependence similar to that of filopodial-dominated, anisotropic spreading fibroblasts [26], underscoring that quantitative image analysis in motility studies can allow us to compare motility modules across cells and even between different cell-types.
Although little is known about the mechanisms that govern midgut motility in invertebrates, there is evidence of coordination between different portions of the gut.
The interplay between different oscillatory modules (active hair bundle motility and electric oscillations) remains to be explored in more detail in future investigations.
