Tetrodotoxin-Producing Bacteria

The beauty of the ocean is unreplicable. From the gentle swaying of its waves to the deepening shades of its blue hue, this vast blue world is alluringly beautiful not only for its serene, vivid scenery but also for its medley of marine life. Many of these otherworldly creatures, though fascinating, lurk in the ocean as some of the most dangerous and deadly predators of the marine ecosystem.

One such creature is the Blue-Ringed Octopus, which consists of at least 10 species. Despite only weighing 28 grams and ranging from 12 to 20 cm long, the Blue-Ringed Octopus was deemed as the deadliest of all cephalopods due to its venomous bite. Although the bites themselves are often painless, the venom contained in their saliva produces a rather opposite effect. A major component of this venom is tetrodotoxin (TTX), a potent neurotoxin that interferes with the transferring of signals between nerve cells and muscle cells by blocking the sodium channels on nerve cells. However, TTX isn’t produced by the Blue-Ringed Octopus itself, but instead by the symbiotic bacteria present within the octopus’s salivary glands. Bacteria that produce TTX include Alteromonas, Pseudomonas, Aeromonas, Bacillus, and Vibrio. Depending on the amount of venom that has entered the wound, the TTX may cause perioral and intraoral paresthesia, nausea, vomiting, muscle weakness, and difficulty breathing, along with flaccid muscular paralysis and respiratory failure if the wound is severe.

Chemical structure of tetrodotoxin

Picture Source: pubchem.ncbi.nlm.nih.gov