Biomarker discovery and time series profiling of the Florida manatee (Trichechus manatus latirostris) upon exposure to the Florida red tide (Karenia brevis) using bottom-up, quantitative plasma proteomics.

Faith Peplinski, Kelly Rein, Celina Ceballos, Cathy Walsh

Florida Gulf Coast Univeristy

Karenia brevis is a harmful marine dinoflagellate that can be concentrated in massive blooms, known as the Florida red tide, almost annually along the west coast of Florida. This organism releases brevetoxins, a suite of potent neurotoxins that may cause massive marine wildlife mortality events, including marine mammals such as Florida manatees. Seagrass can accumulate K. brevis cells which can cause sickness and death of manatees who ingest this vector of toxins.  Manatees that strand due to red tide exposure may be rescued and transported to rehabilitation facilities for treatment and eventual release into the wild.  Manatees are exposed to numerous threats including cold stress and viruses. There are no diagnostic criteria for red tide poisoning other than stranding in association with a recent bloom. However, there is often a lag of several weeks between a bloom and a stranding. The aim of this project is to identify plasma biomarkers for red tide exposure in the Florida manatee. Plasma samples were taken from red-tide rescued manatees through Mote Marine Laboratory’s manatee research program and wildlife hospital at almost regular intervals over time throughout the animals’ recovery. These were compared to samples taken from healthy free ranging manatees during routine health screenings. Plasma proteins were analyzed using bottom-up quantitative tandem mass tag (TMT) labeled proteomics by liquid chromatography tandem mass spectrometry (LC-MS/MS) technology.  Raw data was analyzed using Proteome Discoverer and searched against the Trichechus manatus latirostris proteome (UP000248480). Protein level data was analyzed using Perseus.  Twenty-four proteins were significantly different in red tide exposed compared to healthy manatees. Time series profiling indicated that these proteins returned to healthy levels very slowly (weeks).  With anticipated increases in severity and duration of red tide blooms due to climate change, the threatened status of the Florida manatee, this study seeks to better understand the effects of red tide poisoning and to identify biomarkers for diagnosis.