24 December, 1996
It's Christmas Eve, although it wasn't traditional, it was an exciting day for me. Since Bill and Gamini left three weeks ago, I seem to have gotten bogged down. I've had trouble isolating a compound for an experiment I wanted to complete before leaving. In addition to the lab work, samples of algae mats from different locations around the Sound need to be collected. That has always been enjoyable even though it's physically demanding. Typically it means hiking in rough terrain with a pack that's heavier than I like to carry. Each sample also needs to have chemicals extracted, concentrated, and assayed.
The assay are to determine if the extract will inhibit the growth of specific species of bacteria or fungus. After processing samples for about a week, I've found one that has anti-fungal properties. Two night ago, I got my first hint that the extract inhibited the growth of a parcticular fungus. I wanted to be certain that the experiment was done correctly so I repeated it again last night. When I checked the incubator, the results were the same, no fungal growth. Now I need to try to isolate the compound in the extract that was responsible.
The process will be to take the extract and separate it into chemically unique factions. Each fraction will be again assayed. Hopefully, one will still be active. The active fraction will be separated again and the process repeated until the activity remains with a fraction that contains a single compound.
I've included pictures of two microbial assays. Each Petri dish contains a nutrient that supports the growth of the specific microbe being used in the assay. The small circles arranged in the Petri dishes are paper disks which have been saturated with two milligrams of extract. Before the disks were added, the dish was smeared with fungus. In the dish on the left, the fungus grew over the disks and the pink background can not be seen. We can conclude that those compounds do not inhibit the growth of the microbe on the dish. On the right, the pink background can be seen around the disks. Those are regions where the fungus did not grow. The extract on those disks contains compounds that we would like to identify.
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