The Development of a Single-cell Field Diagnostic for Nitrogen Limitation in Harmful AlgaeEPA Grant Number: R830415
Title: The Development of a Single-cell Field Diagnostic for Nitrogen Limitation in Harmful Algae
Investigators: Dyhrman, Sonya , Anderson, Donald M.
Institution: Woods Hole Oceanographic Institution
EPA Project Officer: Hiscock, Michael
Project Period: November 18, 2002 through November 17, 2005 (Extended to August 17, 2007)
Project Amount: $451,953
RFA: Ecology and Oceanography of Harmful Algal Blooms (2002) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water Quality , Ecosystems , Water
Description:This project proposes the development of an assay to identify cell-specific acetylglucosaminidase activity using the substrate ELF-NAG (ELF 97 N'-acetylglucosaminide). Preliminary data indicates this enzyme is nitrogen-regulated in Alexandrium and that this assay could be an important new tool for identifying and monitoring nitrogen nutrition in field populations of harmful algae. In short, this work addresses gaps in our knowledge of nutritional physiology in harmful species and in our ability to identify the nutritional factors that regulate bloom dynamics.
The research proposed here will test and further refine an assay for the N'-acetylglucosaminidase activity using the ELF-NAG substrate. Specific objectives are to: 1) Test for ELF-NAG labeling in a suite of HAB species. 2) Pursue a method for quantifying ELF-NAG labeling on a single-cell basis in a model Alexandrium species. 3) Relate the regulation of the ELF-NAG labeling to the physiological condition of the Alexandrium cells. 4) Further characterize the physiological function of the N'-acetylglucosaminidase enzyme. 5) Develop the assay for use on field populations of Alexandrium fundyesne. 6) Test the assay on field populations of the toxic dinoflagellate A. fundyense during nutrient addition experiments in limno-corrals
The research will be performed with a suite of harmful algae in the laboratory to identify the regulation of N'-acetylglucosaminidase activity. More detailed studies will focus on Alexandrium to refine a single-cell assay for N'-acetylglucosaminidase activity that can be used in field populations.
This research will advance our knowledge of nitrogen assimilation and nitrogen stress responses in harmful algae. We anticipate the development of a well-tested method for identifying single-cell N'-acetylglucosaminidase activity in different genera. As this enzyme appears to be indicative of nitrogen stress in Alexandrium, such an assay could be used to identify nitrogen stress in field populations.