Using Inhibitors to Investigate the Involvement of Cell Signaling in Predation by Marine Phagotrophic Protists

• Published in: The Journal of eukaryotic microbiology Vol. 55; no. 1; pp. 18 - 21
• Main Authors: HARTZ, AARON J, SHERR, BARRY F, SHERR, EVELYN B
• Format: Journal Article
• Language: English
• Published: Malden, USA Malden, USA : Blackwell Publishing Inc 2008; Blackwell Publishing Inc; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Apoptosis; Autoecology; Biological and medical sciences; Cell signaling; chemosensory response; Chemotaxis; Ciliophora - drug effects; Ciliophora - physiology; Dinoflagellida - drug effects; Dinoflagellida - physiology; Fundamental and applied biological sciences. Psychology; heterotrophic protist; Oxyrrhis marina; Phagocytosis - drug effects; prey ingestion; Protein Kinase Inhibitors - pharmacology; Protozoa. Invertebrata; Receptors, G-Protein-Coupled - antagonists & inhibitors; Seawater - parasitology; Signal Transduction - drug effects; Uronema (Algae); Uronema sp; Predator prey relation; Protozoa; Algae; Oxyrrhis marina; prey ingestion; Cell signaling; heterotrophic protist; Ingestion; Marine environment; Prey; Uronema sp; Signal; Dinophyta; Chemosensitivity; chemosensory response; Ciliata; Inhibitor; Predation; Cell
• ISSN: 1066-5234; 1550-7408
• DOI: 10.1111/j.1550-7408.2007.00297.x

Phagotrophic protists are major consumers of microbial biomass in aquatic ecosystems. However, biochemical mechanisms underlying prey recognition and phagocytosis by protists are not well understood. We investigated the potential roles of cell signaling mechanisms in chemosensory response to prey, and in capture of prey cells, by a marine ciliate (Uronema sp.) and a heterotrophic dinoflagellate (Oxyrrhis marina). Inhibition of protein kinase signal transduction biomolecules caused a decrease in both chemosensory response and predation. Inhibition of G-protein coupled receptor signaling pathways significantly decreased chemosensory response but had no effect on prey ingestion. Inhibitor compounds did not appear to affect general cell health, but had a targeted effect. These results support the idea that cell signaling pathways known in other eukaryotic organisms are involved in feeding behavior of free-living protists.