What produces anatoxin-a?

Anatoxin-a is a neurotoxin produced by multiple genera of freshwater cyanobacteria that are found in water bodies globally. Blooms of cyanobacteria that produce anatoxin-a among other cyanotoxins are increasing in frequency due to increasing temperatures, stratification, and eutrophication due to nutrient runoff.

How does Anatoxin cause paralysis?

1 Anatoxins It is a cholinergic agonist that binds to nicotinic acetylcholine receptors (nAChRs) in nerves and at neuromuscular junctions (NMJs). Subsequent depolarization that opens voltage-sensitive Ca2+ and Na+ channels can lead to muscle paralysis and death by asphyxiation (Falconer, 1998).

Is Anatoxin an agonist or antagonist?

Anatoxin-a is a potent agonist of the nicotinic acetylcholine receptor of bovine adrenal chromaffin cells.

What would happen as a result of anatoxin-a poisoning?

Anatoxin-a is an alkaloid neurotoxin that acts as a potent neuro-muscular blocking agent at the nicotinic receptor. Acute toxicity, following consumption of contaminated water, is characterized by rapid onset of paralysis, tremors, convulsions and death.

Is cyanobacteria always toxic?

Cyanobacteria has many different species; some species are harmless and others produce poisonous toxins. However, not all cyanobacteria are poisonous, and the cyanobacteria that generate toxins do not always do so.

Where does saxitoxin come from?

Introduction. Saxitoxins are produced in freshwater and marine environments. In marine environments, they are often referred to as PSPs. Most human saxitoxin toxicoses have been associated with the ingestion of marine shellfish, which accumulate saxitoxins produced by marine dinoflagellates (Cusick and Sayler, 2013).

What do Saxitoxins do?

Saxitoxin is a neurotoxin that acts as a selective, reversible, voltage-gated sodium channel blocker. One of the most potent known natural toxins, it acts on the voltage-gated sodium channels of neurons, preventing normal cellular function and leading to paralysis.

How does Anatoxin-a block nervous stimulation?

Anatoxin-a is a powerful agonist of acetylcholine receptors being many times better than acetylcholine itself in stimulating the receptor to open. Anatoxin-a therefore outcompetes and displaces acetylcholine overstimulating the receptor, impairing its function and incapacitating nerve and muscle.

What is Cyanotoxin Anatoxin?

Anatoxin-a The toxin is produced by at least four different genera of cyanobacteria and has been reported in North America, Europe, Africa, Asia, and New Zealand. Toxic effects from anatoxin-a progress very rapidly because it acts directly on the nerve cells (neurons) as a neurotoxin.

Is Cyanotoxin harmful to humans?

Cyanotoxins can cause gastrointestinal, neural, hepatic, or dermal toxicity. The time to onset of GI symptoms after oral exposure is usually 3–5 hours and symptoms can last 1–2 days. Exposure can cause conjunctivitis, rhinitis, earache, sore throat, and swollen lips.

How long do cyanotoxins last?

The time to onset of GI symptoms after oral exposure is usually 3–5 hours and symptoms can last 1–2 days.

How stable is anatoxin-a in the dark?

Anatoxin-a is relatively stable in the dark, but in pure solution in the absence of pigments it undergoes rapid photochemical degradation in sunlight. Breakdown is further accelerated by alkaline conditions.

What is the mechanism of action of anatoxin a?

Anatoxin-a is a nicotinic (cholinergic) agonist that binds to neuronal nicotinic acetylcholine receptors. It has been suggested that the activation of presynaptic nicotinic acetylcholine receptors by anatoxin-a results in an influx of Na+, producing sufficient local depolarisation to open voltage sensitive Ca++ and Na+ channels.

What is the minimum lethal dose of anatoxin-a?

From these experiments, they calculated that the oral minimum lethal dose (MLD) (of the algae, not the anatoxin molecule), for calves is roughly 420 mg/kg body weight. In the same year, Devlin and colleagues discovered the bicyclic secondary amine structure of anatoxin-a.

Can anatoxin-a be found in estuarine environments?

Some freshwater cyanobacteria are known to be salt tolerant and thus it is possible for anatoxin-a to be found in estuarine or other saline environments. Blooms of cyanobacteria that produce anatoxin-a among other cyanotoxins are increasing in frequency due to increasing temperatures, stratification, and eutrophication due to nutrient runoff.