Brevetoxin

Brevetoxin is a type of neurotoxin produced by the dinoflagellate species Karenia brevis. This toxin is responsible for the harmful effects of red tide, a phenomenon that occurs when K. brevis blooms in high concentrations, releasing brevetoxin into the surrounding environment.

Structure and Function

Brevetoxins are cyclic polyether compounds. They are composed of a backbone of alternating ether and carbonyl groups, with various side chains attached. The structure of brevetoxin allows it to bind to voltage-gated sodium channels (VGSCs) in nerve cells, causing them to remain open and leading to uncontrolled sodium influx. This results in continuous nerve firing, which can cause a variety of neurological symptoms.

Effects on Marine Life

Brevetoxin is highly toxic to many forms of marine life, including fish, birds, and marine mammals. It can cause mass fish kill events when K. brevis blooms occur. Marine mammals, such as dolphins and manatees, can be affected by brevetoxin through ingestion of contaminated prey or inhalation of aerosolized toxin.

Effects on Humans

In humans, brevetoxin can cause neurotoxic shellfish poisoning (NSP) when contaminated shellfish are consumed. Symptoms of NSP include gastrointestinal upset, neurological symptoms such as tingling and numbness, and in severe cases, respiratory distress. Brevetoxin can also become aerosolized and inhaled, leading to respiratory irritation and other symptoms in individuals near red tide events.

Detection and Treatment

Detection of brevetoxin in shellfish and environmental samples is typically done through liquid chromatography-mass spectrometry (LC-MS). Treatment for NSP is primarily supportive, as there is currently no specific antidote for brevetoxin poisoning.

Karenia brevis, the dinoflagellate species that produces brevetoxin.

See Also

• Harmful algal bloom
• Shellfish poisoning
• Dinoflagellate