PHYLOGENETIC ANALYSIS OF SELECTED TOXIC AND NONTOXIC BACTERIAL STRAINS ISOLATED FROM THE TOXIC DINOFLAGELLATE ALEXANDRIUM-TAMARENSE

Recent evidence has implicated bacterial involvement in the production of paralytic shellfish poison toxins, which are normally associated w ith bloom-forming algal species, specifically toxic dinoflagellate alg ae. Preliminary reports of the identification of toxin-producing bacte ria isolated from the toxic marine dinoflagellate Alexandrium tamarens e suggested that they belonged to the gamma sub-division of the Proteo bacteria, specifically related to the bacterium Moraxella. Digoxigenin -labelled alpha, beta and gamma ribosomal rRNA probes, hybridized to b oth toxigenic and non-toxigenic bacteria isolated from several strains of Alexandrium tamarense, indicated that the bacteria belonged to the alpha sub-division of the Proteobacteria. Phylogenetic analysis of sm all subunit ribosomal RNA coding regions confirmed this and provided s trong evidence that these bacteria are likely to represent a new genus in that group.