Colonial differentiation and hydrophobicity of a Vibrio sp.

A Vibrio sp., isolated from the skin of a barracuda, swarmed over the surface of an agar medium, forming distinct concentric growth zones. Each zone contained cells of characteristic morphology. The surface hydrophobicity measured by the direction-of-spreading method increased from the periphery to the center of the colony, but cells suspended from each growth zone failed to adhere to hexadecane. The high surface hydrophobicity at the center of the colony was correlated with the presence of a loosely bound amphipathic emulsifying agent.