Description of a bacteriocinogenic plasmid in Beneckea harveyi.

A total of 795 strains of Vibrio sp. and Beneckea harveyi, a luminescent marine bacterium, were isolated from various sources in the area of Galveston Island Texas, USA, and screened for the production of bacteriocin-like substances. More than 8% of the Vibrio isolates produce low-MW (dialyzable) substances, which were lethal to a test strain of V. parahaemolyticus. Approximately, 5% of the B. harveyi isolates produced higher-MW (nondialyzable) substances which were lethal to a test strain of B. harveyi. One of the B. harveyi strains (strain SY) produced a nondialyzable substance which was lethal to 2 of 39 strains on B. harveyi. The substance showed no activity toward 17 test strains drawn from the Vibrionaceae and Enterobacteriaceae. Strain SY showed no sensitivity to its own lethal agent and was shown by agarase gel electrophoresis and EM to harbor a single plasmid of 38 times 106 daltons. Variants of strain SY lacking the plasmid were produced by growth in the presence of the antibiotic novobiocin. These variants lacked both the ability to produce the lethal substance and to survive its presence. The lethal agent produced by strain SY is the 1st bacteriocin reported in marine bacteria. The term harveyicin is proposed to name this lethal substance.