Hepoxilins and trioxilins in barnacles: an analysis of their potential roles in egg hatching and larval settlement.
The barnacle life cycle has two key stages at which eicosanoids are believed to be involved in cellular communication pathways, namely the hatching of nauplii and the settlement of cypris larvae. Barnacle egg-hatching activity has previously been reported to reside in a variety of eicosanoids, including 8-hydroxyeicosapentaenoic acid and a number of tri-hydroxylated polyunsaturated fatty acid derivatives, the trioxilins. The production of the eicosapentaenoic acid metabolite trioxilin A4 (8,11,12-trihydroxy-5,9,14,17-eicosatetraenoic acid) by the barnacles Balanus amphitrite and Elminius modestus was confirmed using a combination of high-performance liquid chromatography and gas chromatography, both linked to mass spectrometry. In addition, both species also generated trioxilin A3 (8,11,12-trihydroxy-5,9,14-eicosatrienoic acid; an arachidonic acid-derived product), 8,11,12-trihydroxy-9,14,17-eicosatrienoic acid (a omega3 analogue of trioxilin A3; derived from omega3 arachidonic acid) and 10,13,14-trihydroxy-4,7,11,16,19-docosapentaenoic acid (a docosahexaenoic acid-derived product). In contrast to earlier reports, trioxilin A3 had no E. modestus egg-hatching activity at any of the concentrations tested (10(-9)-10(-6) mol l(-1)). The unstable epoxide precursor hepoxilin A3, however, caused significant levels of hatching at 10(-6) mol l(-1). Furthermore, the stable hepoxilin B3 analogue PBT-3 stimulated hatching at 10(-7) mol l(-1). Neither trioxilin A3, hepoxilin A3 or PBT-3 at 0.25-30 micromol l(-1) served as settlement cues for B. amphitrite cypris larvae.
Vogan
Claire L
CL
School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UK.
Maskrey
Ben H
BH
Taylor
Graham W
GW
Henry
Sheelagh
S
Pace-Asciak
Cecil R
CR
Clare
Anthony S
AS
Rowley
Andrew F
AF
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis*; D007814:Larva / Q000502:physiology; D009657:North Carolina; D010063:Ovum / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D001468:Thoracica / Q000378:metabolism* / Q000502:physiology*; D006113:United Kingdom
D006893:Hydroxyeicosatetraenoic Acids; C453725:PBT-3 compound; C049212:trioxilin A4; C019121:8,11,12-trihydroxy-5,9,14-eicosatrienoic acid; C038243:8-hydroxy-11,12-epoxyeicosa-5,9,14-trienoic acid; D015126:8,11,14-Eicosatrienoic Acid