Kl. Kimm-brinson et Js. Ramsdell, The red tide toxin, brevetoxin, induces embryo toxicity and developmental abnormalities, ENVIR H PER, 109(4), 2001, pp. 377-381
Brevetoxins are lipophilic polyether toxins produced by the red tide dinofl
agellate Gymnodinium breve, and their neurotoxic effects on adult animals h
ave been documented. In this study, we characterized adverse developmental
effects of brevetoxin-1 (PbTx-1) using an exposure: paradigm that parallels
the maternal oocyte transfer of toxin. Medaka fish (Oryzias latipes) embry
os mere exposed to PbTx-1 via microinjection of toxin reconstituted in a tr
iolein oil droplet. Embryos microinjected with doses of 0.1-8.0 ng/egg (ppm
) of brevetoxin-l exhibited pronounced muscular activity (hyperkinesis) aft
er embryonic day 4. Upon hatching, morphologic abnormalities were commonly
found in embryos at the following lowest adverse effect levels: 1.0-3.0 ppm
, lateral curvature of the spinal column; 3.1-3.4 ppm, herniation of brain
meninges through defects in the skull; and 3.4-4.0 ppm, malpositioned eye.
Hatching abnormalities were also commonly observed at brevetoxin doses of 2
.0 ppm and higher with head-first, as opposed to the normal tail-first, hat
ching, and doses > 4.1 ng/egg produced embryos that developed but failed to
hatch. Given the similarity of developmental professes found between highe
r and lower vertebrates, teratogenic effects of brevetoxins have the potent
ial to occur among different phylogenetic classes. The observation of devel
opmental abnormalities after PbTx-1 exposure identifies a new spectrum of a
dverse effects that may be expected to occur following exposure to G. breve
red tide events.