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Cooliatoxin, the first toxin from Coolia monotis (Dinophyceae)
M J Holmes1, R J Lewis, A Jones
1Southern Fisheries Centre, QDPI, University of Queensland, Australia.
Natural Toxins
|January 1, 1995
Summary
A new toxin, cooliatoxin, was discovered in the dinoflagellate Coolia monotis. This toxin causes hypothermia and respiratory failure in mice, suggesting a potential analogue to yessotoxin.
Area of Science:
- Marine Biology
- Toxicology
- Natural Products Chemistry
Background:
- Coolia monotis, a benthic dinoflagellate, was previously considered non-toxic.
- Marine environments harbor diverse microorganisms with potential pharmacological activities.
Purpose of the Study:
- To identify and characterize novel toxins produced by Coolia monotis.
- To investigate the toxicological profile and potential mechanisms of action of the newly discovered toxin.
Main Methods:
- Purification of cooliatoxin from cultured Coolia monotis.
- In vivo studies in mice to determine lethal dose (LD50) and observe toxic effects.
- In vitro studies on isolated nerve and muscle preparations (mouse phrenic nerve, diaphragm, guinea pig atria, vas deferens).
Main Results:
- A novel toxin, cooliatoxin, was isolated and identified as a likely mono-sulfated polyether compound (M=1,062).
- Intraperitoneal administration of cooliatoxin (LD50 = 1 mg/kg) induced delayed hypothermia and respiratory failure in mice.
- In vitro, cooliatoxin stimulated and blocked unmyelinated nerves, and caused a delayed positive inotropic effect on guinea pig atria mediated by noradrenaline release.
Conclusions:
- Cooliatoxin is a novel toxin from Coolia monotis with a potential structural similarity to yessotoxin.
- The observed in vitro effects do not fully explain the lethal effects in mice, suggesting a central nervous system action.
- Cooliatoxin represents a new threat in marine toxin research and warrants further investigation.