"The GLFC has the goal of controlling lamprey with a new and better technique by 2010. This could be it," said Peter Sorensen, a professor of fisheries, wildlife and conservation biology who led the study with chemistry professor Thomas Hoye. "Also, lamprey are important to native peoples on the West Coast, who value it for food. This pheromone could help restore lamprey runs by attracting lamprey to suitable spawning beds."
When they stop feeding, lamprey seek out streams for spawning by following the pheromone trails. After arriving at the spawning grounds, a sex pheromone -- which was identified by Weiming Li, an earlier doctoral student of Sorensen -- attracts the females to males. After spawning, which takes a few weeks, the adults die.
It has taken Sorensen and his colleagues about 15 years to find, isolate and purify the pheromone so that Hoye and his colleagues could identify and synthesize it. The key component is a steroid with potency so great that lampreys would smell a single gram dissolved in 10 billion liters of water, enough to fill 5,000 Olympic-sized swimming pools. This level of potency tops that of all other fish attractants, including those of salmon.
To find the pheromone, the researchers extracted 8,000 liters of water from tanks holding 35,000 larvae. The yield was less than a milligram, or 35 millionths of an ounce. Much of the work in isolating and purifying the pheromone was performed by Sorensen's graduate student Jared Fine, while Vadims Dvornikovs, Christopher Jeffrey and Feng Shao in Hoye's lab were integral to synthesizing the key component, called PADS. The chemical structure of PADS is very similar to that of squalamine, a compound made by the "dogfish" shark. Squalamine has been reported to work against cancer by inhibiting the growth of blood vessels that feed tumors but not other blood vessels. The other two components of the pheromone are a second steroid and an already known, lamprey-specific b
Source:University of Minnesota