Collection, isolation and culturing strategies for Oxyrrhis marina

The heterotrophic marine flagellate Oxyrrhis marina is a popular and tractable model organism, being common in the intertidal environment and relatively straight forward to maintain in the laboratory. In this report, based on our experience of collecting and culturing similar to 400 isolates, we provide a quantification of how easy O. marina is to locate and isolate from the environment and subsequently maintain in culture. In addition, we provide a brief review of the literature pertaining to O. marina culturing, stressing in particular the broad physiological tolerance and a wide diet range of this organism. Finally, in the light of the increasing interest in the genetics and genomics of O. marina, and heterotrophic protists more generally, we highlight existing strategies for culturing heterotrophs for -omic applications and summarize our specific culturing approaches for the genomic and proteomic studies of O. marina. In this context, we outline a simplified version of Droop's medium for axenic culturing and offer details on the use of heat-killed Escherichia coli as a simple and robust food source for culturing O. marina in the absence of other eukaryotes and live prokaryotes.