Cell cycle arrest and biochemical changes accompanying cell death in harmful dinoflagellates following exposure to bacterial algicide IRI-160AA.
Bacteria may play a role in regulating harmful algal blooms, but little is known about the biochemical and physiological changes associated with cell death induced by algicidal bacteria. Previous work characterized an algicidal exudate (IRI-160AA) produced by Shewanella sp. IRI-160 that is effective against dinoflagellates, while having little to no effect on other phytoplankton species in laboratory culture experiments. The objective of this study was to evaluate biochemical changes associated with cell death and impacts on the cell cycle in three dinoflagellate species (Prorocentrum minimum, Karlodinium veneficum and Gyrodinium instriatum) after exposure to IRI-160AA. In this study, IRI-160AA induced cell cycle arrest in all dinoflagellates examined. Several indicators for programmed cell death (PCD) that are often observed in phytoplankton in response to a variety of stressors were also evaluated. Cell death was accompanied by significant increases in DNA degradation, intra- and extracellular ROS concentrations and DEVDase (caspase-3 like) protease activity, which have been associated with PCD in other phytoplankton species. Overall, results of this investigation provide strong evidence that treatment with the bacterial algicide, IRI-160AA results in cell cycle arrest and induces biochemical changes consistent with stress-related cell death responses observed in other phytoplankton.
College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA.
Kaytee L
KL
Pokrzywinski
College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA.
Charles L
CL
Tilney
College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA.
Mark E
ME
Warner
College of Earth, Ocean, and Environment, University of Delaware, 700 Pilottown Road, Lewes, DE 19958, USA.
Kathryn J
KJ
Coyne
D002452:Cell Count; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D016923:Cell Death / Q000187:drug effects*; D053837:DNA Cleavage; D004141:Dinoflagellida / Q000187:drug effects* / Q000502:physiology*; D006540:Herbicides / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
D006540:Herbicides; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D010447:Peptide Hydrolases; C108711:DEVDase