Algicidal effects of a novel marine Pseudoalteromonas isolate (class Proteobacteria, gamma subdivision) on harmful algal bloom species of the genera Chattonella, Gymnodinium, and Heterosigma

• Published in: Applied and environmental microbiology 1998-08, Vol.64 (8), p.2806-2813
• Main Authors: LOVEJOY, C, BOWMAN, J. P, HALLEGRAEFF, G. M
• Format: Article
• Language: English
• Subjects: Algae; Animal, plant and microbial ecology; Animals; Applied ecology; Bacteria; Base Sequence; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Brackish; Chattonella; Colony Count, Microbial; DNA, Ribosomal - chemistry; Ecotoxicology, biological effects of pollution; Eukaryota - physiology; Fundamental and applied biological sciences. Psychology; General Microbial Ecology; Gram-Negative Bacteria - classification; Gram-Negative Bacteria - growth & development; Gram-Negative Bacteria - isolation & purification; Gram-Negative Bacteria - physiology; Gymnodinium; Heterosigma; Isolation and description; Marine; Marine and brackish environment; Marine Biology; Mission oriented research; Molecular Sequence Data; Phylogeny; Polymerase Chain Reaction; Proteobacteria; Pseudoalteromonas; Pseudoalteromonas peptidysin; RNA, Ribosomal, 16S - genetics; Water Microbiology
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.64.8.2806-2813.1998

During a bacterial survey of the Huon Estuary in southern Tasmania, Australia, we isolated a yellow-pigmented Pseudoalteromonas strain (class Proteobacteria, gamma subdivision), designated strain Y, that had potent algicidal effects on harmful algal bloom species. This organism was identified by 16S rRNA sequencing as a strain with close affinities to Pseudoalteromonas peptidysin. This bacterium caused rapid cell lysis and death (within 3 h) of gymnodinoids (including Gymnodinium catenatum) and raphidophytes (Chattonella marina and Heterosigma akashiwo). It caused ecdysis of armored dinoflagellates (e.g., Alexandrium catenella, Alexandrium minutum, and Prorocentrum mexicanum), but the algal cultures then recovered over the subsequent 24 h. Strain Y had no effect on a cryptomonad (Chroomonas sp.), a diatom (Skeletonema sp.), a cyanobacterium (Oscillatoria sp.), and two aplastidic protozoans. The algicidal principle of strain Y was excreted into the seawater medium and lost its efficacy after heating. Another common bacterial species, Pseudoalteromonas carrageenovora, was isolated at the same time and did not have these algicidal effects. The minimum concentrations of strain Y required to kill G. catenatum were higher than the mean concentrations found in nature under nonbloom conditions. However, the new bacterium showed a chemotactic, swarming behavior that resulted in localized high concentrations around target organisms. These observations imply that certain bacteria could play an important role in regulating the onset and development of harmful algal blooms.