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STRUCTURE AND FUNCTION OF SEA LAMPREY
PHEROMONE COMPONENTS
Ke Li1, Cory O Brant1, Mar Huertas1,
Weiming Li1
1 Department of Fisheries and
Wildlife, Michigan State University, Giltner Hall
142, 293 Farm Lane, East Lansing, MI
48824.
December 2014
ABSTRACT:
Migratory and male
mating pheromones are indispensible for sea lamprey reproduction,
and thus are ideal for use to the advantage of sea lamprey control. The main
component of the male pheromone, 3kPZS (7α, 12α,
24-trihydroxy-5α-cholan-3-one-24-sulfate), has been shown unequivocally to
attract ovulatory females to nests. To date, however, no other putative
pheromones isolated from either adult male or larval sea lampreys have been
shown to influence the distribution or behavior of adult sea lampreys in
streams. In this study we elucidated the structures and functions of additional
pheromone components. Using an activity-directed fractionation strategy, we
extracted washings from spermiating male and larval
sea lampreys separately with SPE (solid phase extraction), fractionated the
extracts with TLC (Thin Layer Chromatography) and HPLC (High Performance Liquid
Chromatography), and tested the fractions for their olfactory potency by EOG
(Electro-Olfactogram) recording. We elucidated the
molecular structures of active components by either NMR (Nuclear Magnetic
Resonance) or crystallographic X-ray diffraction, and further confirmed the
structures with spectra of synthesized compounds. The pheromone functions of
isolated and synthesized compounds were tested using in-stream behavior assays
that integrate Passive Integrated Transponder (PIT) technology and visual
observation. Using these approaches, we identified nine compounds, confirmed
that three compounds have putative migratory functions and one compound has
putative mating pheromone functions. We expect that further studies of these
compounds may lead to novel or additional strategies for integrated sea lamprey
management.