The Cephalopod’s Syllabus: Venoms and Toxins

BY MASHA DOLGOFF
University of South Florida Sarasota-Manatee STEM major

Here in Southwest Florida, we’re lucky enough to have vibrant sea-life that includes a couple species of octopuses. These fascinating creatures, belonging to the animal class Cephalapoda, are known for their remarkable intelligence. Their ability to constantly expand their knowledge of their environment has inspired this column.

For the winter session, I wanted to write about the focus of my current research internship at the Roskamp Institute in Sarasota. The institute specializes in a wide variety of neurological topics, including traumatic brain injury, Alzheimer’s, and posttraumatic stress disorder. One of its research areas is uniquely regional: figuring out if there is a connection between the extent to which patients are affected by the Red Tide, which produces a neurotoxin, and key genetic factors. This is the team I’m currently working with under research scientist Dr. Laila Abdullah, and it has caused me to reflect on the way Florida’s ecology has impacted my own life.

As a relative newcomer to Florida who has lived here for close to two years, my first impression of the state was heavily impacted by Hurricanes Milton and Helene. Suddenly, the subtropical flair of my surroundings, which seemed like such a colorful novelty compared to my hometown of Chicagoland, took on the look of untamable wilderness. To observe the house where I lived transformed overnight by an unstoppable motion of the sea was a shock. As we transition to a mild Florida winter from an autumn that seems like it’s been calmer so far (knock on wood), I’ve had more time to think about how the environment affects us.

How do we continue to acknowledge the fragility of nature when it presents itself as a temporary antagonist in our lives?

Perhaps we should consider as a microcosm a feature of Florida’s ecosystem that many people may have a natural fear of, especially those less familiar with them—snakes. My professor of genetics at the University of South Florida, Dr. Ryan McCleary, grew up across the street from a herpetologist. That’s where his love of this curious reptile originated, and he went on to complete his PhD on the evolution of venom in the Florida cottonmouth.

“There is a debate whether it’s a natural fear or a learned fear. Probably deep in our ancestry, there is a reason for primates to be afraid of snakes, especially large snakes,” he said in an interview I conducted with him in October. “But nowadays, with humans, it’s not so much a natural thing.”

Speaking of his childhood growing up just a few houses away from the herpetologist, “He had frogs and turtles and snakes and lizards and all sorts of stuff and we just thought that was the coolest. So, kind of what the neighborhood kids did—instead of, you know we did our fair share of baseball in the summer—but mostly we went down to the pond in the river and caught turtles and snakes,” McCleary said.

Even those without such a childhood connection may be able to gain an appreciation for snakes through the lens of biodiversity. To understand why protecting these rapid serpentine locomotors might be in our own self-interest, we must first consider why they produce neurotoxins in the first place.

“A lot of people think that the point of venom is to kill prey, and it’s really not. The point is to stop it so you can eat it,” McCleary said. “But the other thing is that if you look at the nerve synapse, from one nerve to the next, or from a nerve to a muscle, there’s all these different parts that have to work just right and all you have to do is mess up one of them.”

However, just like too much of anything can be poisonous, certain poisons can be strategically engineered to be healing.

Originally isolated from Brazilian pit viper venom, the biomolecule bradykinin potentiating peptide (BPP) contributes to prey losing its consciousness, but it also helped design drugs to treat hypertension in humans. “You might have heard of a group of pharmaceuticals called ACE inhibitors,” McCleary said. “A lot of people take them as blood pressure medications. Those were developed from snake venom.” That’s precisely why protecting biodiversity is so important. We don’t know what kind of potentially life-saving, undiscovered medicines might be hiding even within the most threatening characteristics of our fellow earth dwellers.

On the other hand is Brevetoxin, the neurotoxin produced by the Red Tide organism Karenia brevis, the dispersal of which occurs across much broader channels in the ecosystem than those to which snake venom is confined to. It both aerosolizes into the air and is passed down through the food chain, disrupting electrical signaling in the cells of many different organisms, from birds to fish to humans.

At the Roskamp Institute, my direct supervisor, Gregory Aldrich, was the lead author on a scientific study published last year examining the possible connection between exposure to Brevetoxin and indicators of cognition in people with a certain genetic risk factor for Alzheimer’s and other neurological disorders. The genetic risk factor in question is a form of the APOE gene; the gene helps build proteins that deliver specific nutrients to the brain. His research found that the risk factor was associated with increased odds of self-reported fatigue and memory problems following exposure to Brevetoxin.

With that in mind, we have one more concern to add to the long list of reasons why we should figure out what causes the Red Tide and how to stop it. The Red Tide is a type of Harmful Algal Bloom (HAB), which, generally speaking, starts because of an excess of nutrients in the water, usually driven by human activities such as fertilizer runoff and wastewater leaks. Algae feed on the nutrients, after which they produce toxins that cause them to outcompete other sea-life, allowing them to basically hog all the oxygen in the water. Warming oceans also help algae proliferate compared to many other species—the same warming oceans that increase chances of hurricanes forming.

However, when I spoke to Karen Atwood, a biology instructor at my university who did her Master’s on Brevetoxin in seabirds of southwest Florida, she told me that blooms of K. brevis cannot be definitively traced to an excess of nutrients, as they start 10 to 50 miles offshore in oligotrophic water, or water that is low in nutrients. “And the million-dollar question is, why do they start? We don’t know quite yet,” she said.

Water that is warmer than usual can certainly expand into areas where HABs, including K. brevis, can dwell once they start, but the initiation of the Red Tide remains somewhat of a mystery. There are a few current theories; the leading one of which suggests that thermal and salinity fronts can carry K. brevis from oligotrophic waters to areas where it can explode, but this is just one supported part to an incomplete story.

From fanged megafauna that can be more useful than threatening in deliberately organized circumstances, to a tiny microorganism that has disproportionately profound effects, it seems we still have much to understand and discover in the curiosities, thrills, and dangers provided to us by the special habitat we live in.