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Dutch-based researcher Ronald Osinga holds an exotic coctail -- atually it's a Pyrex container holding a vibrant, convoluted sponge, Teichaxinella sp.
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Extraction
by Dr. Amy Wright
 Chemists on the Keys expedition will prepare extracts of each of the organisms we collect. Once we return to the laboratory at HBOI, these extracts will be used in our biological screening program. What is an "Extract"?
Anyone who drinks tea or coffee is familiar with the extraction process. Boiling water, poured over dried and ground up tea leaves or coffee beans "extracts" various chemicals (flavorings and natural products such as caffeine) from the dried plant tissue, creating a tasty beverage.
On the ship, we prepare extracts of the plants and invertebrates we collect by grinding them up in a high speed blender with ethyl alcohol. We use alcohol rather than boiling water because many of the compounds we seek don't hold up well to boiling. After trying out lots of different organic solvents, we found that ethyl alcohol provides excellent extraction efficiency and is safe for our chemists and for the cells and enzymes we eventually use to test these extracts. |
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"We have to make sure our samples have the target compound," she said, pointing to a carefully reproduced graphic of the lasonolide molecule. "Just because we found it last time doesn't mean it will be here again. There is always a chance it won't be. The sponge's production of the compound could be seasonal, location-specific, or it might be getting produced by some symbiotic microorganism."
To determine if the samples gathered daily have any interesting chemistry, Wright begins by preparing an extract. She blends and dissolves small pieces of sponge -- or whatever the sample du jour may be -- in ethyl alcohol. Ordinarily, she would analyze the resulting liquid with TLC (that's Thin-Layer Chromatography). But, she's testing a new machine on board that provides more precise results. The High-Performance Liquid Chromatograph (HPLC for those in the know) is part computer, part intravenous drip, part tanning booth. It bombards injected samples with ultraviolet energy. Half an hour later it spits out a graphical representation of compounds contained in the sample. The peaks and valleys of these graphs are as unique as fingerprints.
"We're looking for ones that are different from what we already know," Wright says, casually calling off compounds based on nothing but their visual signatures. "If we find anything interesting, then we target them for additional studies, both internally (HBOI) and at pharmaceutical companies."
August 9, 8:56am, Gulf of Mexico, 90 miles west of Naples, Florida -- With the current in our favor, the R/V EDWIN LINK drifted gently through the night, traveling only 7 miles to this morning's dive site. Today's dives will perhaps be the last ones to these relatively shallow depths. Owing to the overwhelming success in locating the Forcepia sponge, we will soon move further north into the Gulf to investigate deeper waters, 1000 to 2000 feet down. Scientist are not exactly sure what they will find there.
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The R/V EDWIN LINK lowers the JOHNSON-SEA-LINK
submersible into the calm waters of the Gulf of Mexico.
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CLICK HERE to learn more about
our correspondent, Mark Carroll. |
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