Ultrastructural Features and Strategy of Intermicrobial Interaction of Cells of a Novel Isolate, Microbacterium sp. Viol, a Violet Pigment Producer

A gram-positive bacterium, strain Viol, belonging to the genus Microbacterium, was isolated from a sample of soddy-podzolic soil taken in the vicinity of Pushchino (Moscow oblast). The strain formed intensely colored colonies of violet or red-violet color on agar media, which was not typical for representatives of this genus. A feature of the fine structure of cells of the strain Viol was the presence of an extensive capsule, organized in the form of chaotically oriented ultrastructures resembling needle-shaped crystals surrounded by a polysaccharide matrix. A violet pigment was extracted from the cells of the novel isolate and characterized. The experimental data obtained indicate a new mechanism of intermicrobial antagonistic action, which is implemented by cells of the Viol strain in the presence of alien bacteria, which is probably a moderate predatory “wolf pack” lifestyle.