An essential element in the understanding of HAB events is the ability to accurately assess how much toxin is present. In addition, researchers want to know which algae produce toxins and to be able to identify these toxin producers quickly and accurately. In order to develop predictive or early-warning systems for HABs we need far more sensitive detection methods for both the toxins and harmful algae. Currently we are undertaking the following projects that will help develop these tools.
ELISA is an abbreviation for "enzyme-linked immunosorbent assay."
It is a rapid immunochemical test involving an enzyme (a protein that
catalyzes a biochemical reaction) in addition to an antibody or antigen
(immunologic molecules). These kinds of methods can quickly yield visual
results, that depend on the concentration of toxin in a sample. But
the most important aspect of this test is that it can be highly sensitive
and specific for a given molecule, such as domoic acid. So far, several
methods have been proposed for domoic acid detection. While they can
be successfully conducted in a standard equipped laboratory, their application
in the field or on shipboard requires some modifications. The ELISA
is a rapid analytical method for domoic acid detection in these locations
other than a standard laboratory.
We are currently working with the Washington State Department of Health, Washington Department of Fish & Wildlife, and coastal Indian tribes to evaluate the use of ELISA kits. These kits use a technology similar to that employed in home pregnancy tests; however they are still considered experimental and the parameters for their implementation need to be developed. In addition, confidence in their ability to reliably detect the presence or absence of marine biotoxins must be demonstrated to the satisfaction of risk managers. Of particular concern is the occurrence of so-called false negatives, the detection of no toxin when it really is present. This validation study is a collaboration with the Coastal Indian Tribes (Makah, Quinault and Quileute), the Washington State Department of Fish & Wildlife, and the University of Washington's Olympic Natural Resources Center (ONRC).
To read more about the validation of ELISA field kits, please visit the following link: Validation of ELISA field kits
Not all Pseudo-nitzschia species produce domoic acid, therefore
species identification is important; however, this is very difficult,
if not impossible, using standard light microscopes. At present, we
routinely observe Pseudo-nitzschia cells in water samples as
an early warning signal. When these cells are seen in samples, increased
sampling and tests are initiated. In order to identify the toxic species,
a scanning electron microscope (SEM) and time consuming laboratory procedures
are required. Clearly, the ability to rapidly identify toxin producing
cells in samples would reduce costs, effort, and resources. The use
of polymerase chain reaction (PCR) techniques permits the development
of very specific probes for each species of Pseudo-nitzschia.
Presently we are developing probes for all of the species of Pseudo-nitzschia
found along the West Coast in collaboration with researchers at the
Monterey Bay Aquarium Research Institute (MBARI) and University of Maine.