Roman, do you mean"thumbling". well, thumbling is the characteristics of Listeria which has a peritricate flagella. And flagella as we know is used as a medium of movement for most organisms.. so i think thumbling for some organisms can be a true motility, since through thumbling an organism can move away from its location.
Tumbling is the true motility while twitching may not be the true motility
http://www.microbiologybytes.com/video/motility.html gives a good overview of the microbial motility types. Mostly run & tumble and likely somewhat responsive to chemical gradients.
Roseanne Ford's group at UVA (among many others) has done some groundbreaking & very rigorous determinations of the mobility & chemotactic responses of bacteria.
Difference between bacteria and organisms are also reflected in the differences of the movement. Living organisms over time. The bacteria need the space. Along with the space, the movement of the bacteria is related to the concentration gradient.
In the bacterial motion studied by Howard Berg, which may be representative of many species, "tumbling" is but one phase of a two-phase switch. In the other phase, the flagellar motor rotates in the opposite direction and propels the bacterium in a straight line, like an outboard motor. Chemotaxis, toward attractants and away from repellants, is achieved by regulating the timing of the switch between the two phases.........more time in the "ON" phase and less time in the "OFF" (tumbling) phase for attractants and vice versa for repellants.
The peritrichous bacterium Escherichia coli is a well-studied example of a microswimmer in nature—one that is able to change its swimming direction actively, showing “run-and-tumble” motion. A cell swims by rotating multiple helical flagella, each of which is attached by a hook to a rotary motor on the body . When all rotary motors rotate in the same direction, the cell swims forward (i.e., a run state). The cell changes direction by reversing the rotation of at least one of the motors (i.e., a tumble state). Although a tumble reorients the cell in a random direction, it is able to migrate stochastically toward a more favorable environment by changing the frequency of the reorientation—depending on the gradient of the temperature or concentration of molecules of interest (i.e., sugars, amino acids, dipeptides) .
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2800969/
A more detailed account of the same basic switch between flagellar modes that I described. Thank you, Buenaflor.
Dear Roman, I am in agreement with most of the discussion listed here, but I would make two points. First, tumbling per se is not a means of motility, but it is part of the movement - tumbling cycle seen in flagella-mediated motility (generally called swimming) as mentioned above. Secondly, some observations suggest that there may be another element operating in the cycle - flicking - where individual flagella straighen out to move the cells before the next run. This is recently reported for Pseudomonas fluorescens SBW25 by Ping et al., FEMS Microbiol Ecol. 2013. Regards, Andrew.
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