North Pacific Isolated Alteromonas macleodii Strain has a Broad Algicidal Effect, Likely Mediated by Protease Secretion

Algae account for roughly half of global carbon dioxide absorption and are a large and diverse group of primary producers. Understanding the complexities of algal interactions with its environment is important in furthering understanding of important biogeochemical cycles. Previous research has determined that marine bacteria Alteromonas macleodii (A. mac) independently secretes an extracellular substance that kills model diatom Thalassiosira pseudonana. The specific mechanism is unknown, but a potential candidate is extracellular protease. We designed an experiment to test whether A. mac secretes proteases at an easily detectable concentration. Our results distinctly indicated that A. mac independently secretes extracellular proteases. Additionally, we tested the specificity of A. mac’s algal killing effect by replicating the preliminary experiment on five additional species spanning 3 classes and 5 genera. Four out of six species were negatively affected, suggesting a broad spectrum of the killing effect. In the open ocean, A. mac encounters an abundance of algal species. Deepening the understanding of the range of A. mac's effect provides more information about how networks of microbes may impact each other in the environment and the potential impacts these interactions may have on biogeochemical cycles.

Presentation Preference: Poster

Primary Presenter: Riley Dunklin, Cypress College (riley.dunklin@gmail.com)

Authors:

Riley Dunklin, Cypress College  (riley.dunklin@gmail.com)

Megan Schatz, University of Washington  (megdawg@uw.edu)

Zinka Bartolek, University of Washington  (zinkab@uw.edu)

Ginger Armbrust, University of Washington  (armbrust@uw.edu)

David Wiener, University of Washington  (dawiener5@gmail.com)