> Found in a water sample taken from the Ganges, India. I just testet a
> little of the water on LB + glucose to see the microflora. It caught my
> attention since it inhibited other microorganisms (a few mm of
> inhibition zone).
This is very interesting ! I would bet these bugs secrete biocins of some
sort. If biocin secretion is associated with e.g. glucose in the medium, and
if the bug is slightly sensitive to the biocins as well, perhaps this would
explain the weird colony formation.
Alternatively, you might have a silent gene that gets triggered every so
often, so that from time to time you get cells that 'feel like exploring' so
to speak, and swim off to generate new colonies. This won't explain why you
do not get a colony at the initial streak site, *unless* the 'exploratory'
behavior is triggered every time you move the bug from one plate to the
other - either through mechanical stimulus or minor differences in oxygen
levels, nutrients, etc.
Alternatively, you might have contact stimulation instead of contact
inhibition and the colonies form when sufficient number of cells
accidentally stay in one area long enough to secrete the chemicals necessary
for rapid division. The rest of the cells keep wandering around or die.
It would be interesting to see how this bug grows in liquid medium, because
if this is chemical stimulus kind of thing you might get very very slow
growth (large volume of liquid to saturate), followed by burst of division
after a long slow growth period. Kind of exaggerated version of normal lag