The Deadly Sting of the Giant Nomura's Jellyfish

The giant jellyfish, because of its deadly sting, is one of the most dangerous animals in ocean waters that swimmers can encounter when they go out on a beach outing.

Summer is almost starting in the northern hemisphere, and some of the beaches are set to re-open after the lifting of the lockdowns caused by the COVID-19 pandemic. As always, the beaches will be a popular place for people to flock to for recreation and to cool off from the hot summer sun.

To the swimmers who are unfortunate enough to be stung by the giant jellyfish, they would wish they never entered the water. It is also called Nomura's jellyfish (scientific name: Nemopilema nomurai), and now, scientists have recently identified the deadly components that make up its venom that can be fatal to humans.

The researcher's report can be accessed in the Journal of Proteome Research published by ACS Publications. The study is entitled: "Comprehensive Proteome Reveals the Key Lethal Toxins in the Venom of Jellyfish Nemopilema nomurai."

These species live in the coastal waters of Japan, China, and Korea. This jellyfish can reach a maximum diameter of 6.6 feet or around two meters and can weigh a maximum of 440 pounds or nearly 200 kilograms. This giant species stings a staggering number that reaches up to hundreds of thousands of individuals each year.

Its toxin causes swelling, redness, and extreme pain, and in the worst cases, it causes shock and death. Its venom is composed of a cocktail of various toxins. Many of these components resemble toxins present in other organisms like bacteria, bees, snakes, and spiders.

The report's authors sought out to isolate the toxin that causes death among the many toxins comprising the animal's venom. If they can determine this, they can take the first step in developing a drug or cure to counter the jellyfish's stings and reduce fatalities from stings.

Rongfeng Li and Pengcheng Li, together with their colleagues and co-authors Huahua Yu and Tong Li, captured specimens of the N. nomurai species from coastal areas in Dalian, China. They collected the tentacles of the animals where the venom is contained. From these parts, they extracted the proteins of the toxin. They then separated their components in various fractions with the use of chromatography. Each of these protein fractions was injected into mice to determine which of them were toxic and fatal to the mice.

Necropsies were performed on the mice, and they found damage in various organs, such as the kidneys, heart, liver, and lungs. The scientists conducted mass spectrometry to identify 13 proteins that are toxin-like in the fractions found to be lethal.

The researchers found that some of the proteins from the jellyfish resembled toxic proteins and enzymes also found in the venoms of different species of spiders, snakes, and bees. The researchers also considered that any single toxin may not necessarily be lethal and that it is probable that multiple enzymes and proteins act in concert and be synergistic with one another to turn into a deadly combination.