Journal of the Marine Biological Association of the UK

Eicosanoids are modulators of larval settlement in the barnacle, Balanus amphitrite

John  Knight a1, Andrew F.  Rowley a1c1, Mizue  Yamazaki a2 and Anthony S.  Clare a2
a1 School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea, SA22 8PP, Wales
a2 Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, England


Eicosanoids are oxygenated derivatives of C20 polyunsaturated fatty acids known to play key roles in many physiological events in both invertebrates and vertebrates. The eicosanoid generating capacity of cypris larvae of the barnacle, Balanus amphitrite, was examined using enzyme immunoassay and high-performance liquid chromatography. These larvae generated the lipoxygenase products, 12-hydroxyeicosapentaenoic acid (HEPE), 8-HEPE and 8,15-diHEPE, together with the cyclooxygenase products, prostaglandin (PG) E, PGF and thromboxane (TX) B. Indomethacin, a selective cyclooxygenase inhibitor, caused a dose-dependent inhibition of PGE generation by B. amphitrite larvae, while esculetin and nordihydroguaiaretic acid (lipoxygenase inhibitors) also strongly inhibited the generation of 8-HEPE, 12-HEPE and 8,15-diHEPE. PGE2, PGE3 and 16,16-dimethyl PGE2 caused a dose-dependent inhibition of settlement of B. amphitrite larvae while indomethacin (25–100 [mu]M) stimulated this process. Lipoxygenase products (8-HEPE, 12-HEPE and 8,15-diHEPE) as well as esculetin and nordihydroguaiaretic acid (10–100 [mu]M) had no effect on the attachment of larvae.