File:Coast watch (1979) (20471972268).jpg

Title: Coast watch
Identifier: coastwatch00uncs_10 (find matches)
Year: 1979 (1970s)
Authors: UNC Sea Grant College Program
Subjects: Marine resources; Oceanography; Coastal zone management; Coastal ecology
Publisher: (Raleigh, N. C. : UNC Sea Grant College Program)
Contributing Library: State Library of North Carolina
Digitizing Sponsor: North Carolina Digital Heritage Center

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
When the material is cooled, the primers reform bonds on the conserved regions broken during the heating process. Enzymes then begin building DNA on the new strand, which fills in the rest of the gene around the already matched conserved regions. These areas will be either semiconserved (with a degree of similarity in all organisms) or variable (unique for each organism). The end result is a copy of the original DNA. This process is repeated 30 to 50 times, each time doubling the number of strands, to generate millions of copies. Rublee then looks at the sequences of these copies and com- pares them to sequences of other organisms similar to Pfiesteria to determine whether it is truly unique. If it is unique, Rublee can design a probe complementary to it, a piece of synthesized DNA called an oligonucleotide that will seek out its complement on DNA extracted from waters or sediments where the suspect, Pfiesteria, may reside. If Pfiesteria is present, the oligonucleotide will bind to that target. If not, it won't. The mystery isn't solved yet. Next, the scientists testing for the dinoflagellate must confirm that the binding has actually taken place.
Text Appearing After Image:
Loading an electrophoresis gel to check the results of polymerase chain reaction Hitting the Target One method to confirm binding is to use the probe as a primer in the polymerase chain reaction, which would yield many copies of the target if it is present. But certain chemical conditions have to be met for this procedure to work, and all the un- knowns about Pfiesteria make that a chancy course to take. A second method is blotting, chemically hooking another molecule to the probe so that it is larger and has a marker attached. Rublee has blotted with a radioisotope but says that this method requires too many precautions. "We want to use high tech to develop a low-tech method," he says. So Rublee is focusing on fluores- cent in situ hybrid- ization (FISH), the detection strategy he calls "the coolest." Rather than binding to material extracted from the cell, the probe — equipped with a fluorescent marker — enters the cell and binds with the target material inside. The cell can be examined under a microscope after excess probe material has been washed away. If it glows, binding has occurred. FISH requires minimal equipment and a few hours of time from sampling to results. With a power source and few chemicals on hand, it could be used to test waters on site. But using this method on Pfiesteria poses a few thorny problems that Rublee is working to solve. First, after consuming algae, Pfiesteria retains some of the natural fluorescence from the plant's chloro- plasts. Also, the cell walls of the dinoflagellate itself fluoresce. These natural sources of fluorescence could interfere with the probe's effectiveness by masking the specific fluorescence from the probe. Rublee equates this to Continued COASTWATCH 7

Note About Images