Algicidal activity of Aeromonas hydrophila sdPS-7 isolate against toxic marine dinoflagellate Alexandrium minutum KB- 5
- Author:
Shaima Abdul fattah
;
Gires Usup
;
Asmat Ahmad
- Publication Type:Journal Article
- Keywords:
Alexandrium minutum;
Aeromonas hydrophila;
algicidal;
marine
- MeSH:
Biological Control Agents;
Aeromonas hydrophila
- From:Malaysian Journal of Microbiology
2016;12(1):24-29
- CountryMalaysia
- Language:English
-
Abstract:
Aims: Several harmful dinoflagellate species are widely found in Malaysian marine waters. These microalgae are
capable of producing a variety of toxins that can intoxicate humans through consumption of contaminated seafood.
Therefore, the present work aimed to investigate the potential of a marine bacterium sdPS-7 isolate as a biological
control agent against Alexandrium minutum KB-5.
Methodology and results: The isolate sdPS-7 was obtained from marine sediments in Malaysia and examined for its
algicidal activity toward the toxic dinoflagellate A. minutum KB-5 in laboratory culture. Based on morphological and
molecular characterization, this isolate was identified as Aeromonas hydrophila sdPS-7. Alexandrium minutum KB-5
cultures were exposed to cell free bacteria culture filtrate and the effect on dinoflagelate growth was evaluated based on
direct cell counts in the treated samples compared to non-treated control cultures. The bacterial filtrate was treated at
different temperatures, salinities and exposed to repeated freezing and thawing five times to study its algicidal activity
stability thereafter. The results showed a potent inhibition of the growth of A. minutum KB-5. The strongest effect was
observed when the bacterium culture filtrate was mixed with A. minutum KB-5 cultures that were in lag phase, resulting
in 99% or higher mortality. The cell-free filtrate proved to be heat- stable when exposed to temperatures of 2 °C to 100
°C for one hour each. There was also no substantial salinity as well as (freezing – thawing) effect on the filtrate algicidal
activity.
Conclusion, significance and impact of study: This study illustrated the potential use of the marine bacterial
Aeromonas hydrophila sdPS-7 filtrates in controlling the growth of the toxic dinoflagellate A. minutum KB-5.
- Full text:P020160317501816217960.pdf
