SerpApi.Org
Here’s what you’ll learn when you read this story:
- “Red tide” algal blooms, largely caused by single-celled organisms in the genus Alexandrium, produce a natural neurotoxin called saxitoxin that can cause paralytic shellfish poisoning in humans.
- For years, scientists at the University of California San Francisco have investigated saxiphilin, a naturally-occurring protein in frogs, as a kind of a “molecular sponge” to neutralize saxiphilin.
- A new study successfully demonstrated the effectiveness of saxiphilin as an antidote in mice, and the researchers believe the protein will also inhibit many variants.
In July 2022, scientists from Woods Hole Oceanographic Institution (WHOI) aboard the research vessel Norseman II documented the largest “red tide” toxic bloom ever seen in polar waters. The work of a single-celled organism called Alexandrium catenella, these toxic blooms are particularly dangerous, as they produce a powerful neurotoxin called saxitoxin. These toxins can then accumulate in bivalves (such as mussels, clams, and oysters) and cause paralytic shellfish poisoning (PSP) in humans.
PSP is a deadly serious affliction—it can paralyze muscles in the chest and abdomen and essentially asphyxiate its victim. The toxin is such an efficient killer that the U.S. military stockpiled it as a chemical weapon during the Cold War. Pilots of U2 spy planes that flew over the Soviet Union carried pills of saxitoxin in case they were captured, and the CIA even developed a weapon that fired a pellet of saxitoxin for quiet assassinations, otherwise known as a “heart attack gun.” There is no known antidote capable of neutralizing this toxin.
Or, more accurately, there was no antidote.
A new study published in the journal Nature Communications reports that saxiphilin—a protein that exists naturally in bullfrogs and other frog species around the world—successfully cured mice with PSP by intercepting the toxin before it attacked nerve and muscle cells. Scientists originally tried to find an antidote by disrupting saxitoxin’s complicated biological processes (which attack nerve cells), but this study took another approach, finding a protein that essentially acts like a “molecular sponge.”
“This was a problem looking for a solution,” Daniel Minor, lead author of the study, said in a press statement. “It turns out that one naturally occurring protein is all that’s required to take this toxin out of commission.”
Saxitoxin works by blocking tiny tunnels in the cell membrane known as sodium-channel proteins. These tunnels are usually closed, but they do allow sodium into the cell. Saxitoxin specifically plugs these channels and causes a cascading effect that paralyzes the body. In 2021, Minor and his team discovered that proteins found in frogs essentially bind to these toxins and reverse the damage. Five years later, Minor proved that saxiphilin can effectively act as an antidote against the deadly neurotoxin—one that’s destined to become more common as the frequency of algal blooms increases globally due to climate change.
“Every animal has evolved its own solutions to the same problems that humans face,” Minor said back in 2021. “When we study adaptations that other animals have come up with, we’re also potentially studying novel solutions that humans can use in our own medicine.”
Saxitoxin is actually a family of toxins with more than 50 variants, but previous studies have shown that saxiphilin is capable of binding with many of these different variants. Minor hopes that future studies focused on specifically engineered versions of saxiphilin could provide even better protection.
“Nature has had to solve this problem multiple times,” Minor said in a press statement. “So, there is resilience to toxins all over the biological world.”
