Dyhrman, S. T. Scripps Institution of Oceanography, sdyhrman@ucsd.edu
Palenik, B. T. Scripps Institution of Oceanography, bpalenik@ucsd.edu

 
THE DEVELOPMENT OF THE ALKALINE PHOSPHATASE SUBSTRATE ELF AS A DIAGNOSTIC TOOL FOR PHOSPHATE STRESS.
 
Alkaline phosphatase activity is a common marker of phosphate stress in many phytoplankton. Yet it has been difficult to attribute alkaline phosphatase activity to specific organisms or groups of phytoplankton in the field with traditional biochemical procedures. A new alkaline phosphatase substrate, ELF (enzyme labeled fluorescence) shows promise in this regard. When a phosphate group is cleaved from the ELF reagent it precipitates and fluorescently labels the site of enzyme activity, thus tagging stressed cells. We have characterized ELF-labeling in cultures of a common dinoflagellate, Prorocentrum minimum in order to understand ELF-labeling dynamics with varying phosphate supply. The ELF labeled enzymes appear to be induced by low concentrations of inorganic phosphate in the media and are repressed when phosphate stressed cells are re-fed with phosphate. The location of the enzymes being labeled has also been investigated. This is critical because whereas extracellular phosphatases are commonly inducible, intracellular ones can be constitutively expressed. After characterization, ELF was used to detect alkaline phosphatase activity in field populations of P. minimum. This study indicates that ELF is an excellent new tool for monitoring phytoplankton phosphate stress in the environment when supported by appropriate laboratory studies.
 
Day: Tuesday, Feb. 2
Time: 04:00 - 04:15pm
Location: Sweeney Center
 
Code: SS41TU0400S