Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 10:15:00 AM

Location: Mesilla

Riffell, J, A, University of California, Los Angeles, Los Angeles, USA, jeffr@protos.lifesci.ucla.edu

Krug, P, J, Univerity of California, Los Angeles, Los Angeles, USA, pkrug@protos.lifesci.ucla.edu

Zimmer, R, K, University of California, Los Angeles, Los Angeles, USA, z@protos.lifesci.ucla.edu

SPERM CHEMOTAXIS AND EGG LIMITATION REGULATE FERTILIZATION IN ABALONE

Sperm chemotaxis and egg concentration were found to regulate fertilization in the free-spawning red abalone, Haliotis rufescens. Sperm responded to a chemical attractant from conspecific eggs, exhibiting both activation and orientation. Computer-assisted video motion analysis demonstrated that sperm doubled their swimming speed in response to egg-conditioned sea water, and 90% of sperm oriented toward and recruited to live eggs over 20 min. Using a flat-capillary assay, sperm exhibited chemotaxis towards the dissolved cue from eggs. The chemoattractant was concentrated from egg-conditioned sea water using a C-18 column, yielding a single active fraction. Reversed-phase HPLC was used to isolate one major UV-absorbing peak, which contained all bioactivity. The purified sperm attractant is less than 500 Da, and is presently being characterized by 1D and 2D NMR. Next, fertilization success was determined for a range of egg (10^2-10^5 egg/ml) and sperm concentrations (10^4-10^8). In contrast to previous reports, absolute fertilization (total number of fertilized eggs) was mediated by the concentration of eggs, and not by sperm limitation.

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Aquatic Sciences Meeting, Albuquerque 2001

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