Plaque Formation by Algicidal Saprospira sp. on a Lawn of Chaetoceros ceratosporum

Abstract

The bacterial strains belonging to the genus Saprospira were isolated from sea water samples in Kagoshima Bay and shrimp aquaculture ponds by using of the mixed culture with marine diatoms and double layer agar techniques. A Saprospira strain SS90-1 formed crater-like plaques on a lawn of Chaetoceros ceratosporum, which enlarged unlimitedly in the way of concentric cycles during an incubation period under illumination. The plaque formation by Saprospira SS90-1 was repressed with antibiotics including penicillin G, ampicillin, strepto-mycin, erythromycin, and tetracycline.