Tag Archives: cone snail

Cone snail snatching a goldfish. Photo: Bionews

New painkillers could be made out of the venom of a killer snail

Cone snails have one of the most dangerous venom in the animal kingdom. This complex venomous soup is made up of thousands of chemicals used both to hunt prey and ward off predators. The venom is enough to kill a human in a matter of minutes. Now, these lethal chemicals could be used to create a new class of painkiller for chronic pain and cancer patients undergoing chemotherapy, according to University of Queensland researchers. The same team also used a genetic and proteomic to find out how the cone snails developed its venom. Apparently, the animals initially used their chemical weaponry as a defense mechanism and later on adapted it into an attack.

Cone snail snatching a goldfish. Photo: Bionews

Cone snail snatching a goldfish. Photo: Bionews

Thousands of peptides (mini-proteins) called conotoxins make up the cone snail venom. Different conotoxins can be found in every Conus species.

The cone snails are quite diverse, too. Some hunt slow-moving worms or other snails, while other species attack fast-moving fish. This is quite a difference. Previously, researchers found cone snails produce and use different venoms for attack and defense. The attacking type is made at the end of the venom duct, while defense venom at the other end. So, by studying the toxins of stunned prey, researchers can tell whether the snails attacked or warded off.

Image: Proceedings of the Royal Society B,

Image: Proceedings of the Royal Society B,

Particularly, to catch fish, the fast-prey hunting cone snails use  delta-conotoxins. These toxins stop nerve signals in their tracks and cause quick and deadly paralysis. The reasoning was that cone snails that hunt slow-moving prey have no need for d-conotoxins. Using novel genetic techniques, however, the team from University of Queensland and Université Montpellier found d-conotoxin (d-SuVIA) in the venom of the worm-hunting Conus suturatus. They also discovered 11 other novel d-conotoxin-like sequences from other worm-eating cone snails.

Moreover, these toxins were produced in the venom duct for defense purposes. So, what gives? Well, when the researchers injected  the toxin into mice, the mice displayed behaviors consistent with intense pain. As we know, pain is a great mood killer for predators. More plainly, these conotoxins – though heavily used by modern species to kill fish – weren’t initially developed to attack, but to stun and scare predators away.

“We propose that defensive d-conotoxins were originally used by ancestral worm-hunting cone snails to protect against threats such as cephalopod and fish predation,” the authors write in Proceedings of the Royal Society B, “and have been repurposed for fish-hunting.”

An evolutionary tree showing the relatedness between the new worm-hunting snail d-conotoxins and the d-conotoxins found in fish-hunting species.  Image: Proceedings of the Royal Society B,

An evolutionary tree showing the relatedness between the new worm-hunting snail d-conotoxins and the d-conotoxins found in fish-hunting species. Image: Proceedings of the Royal Society B,

The study delved deeper than ever before in the cone snail venom chemical and biological makeup. Professor Paul Alewood, from UQ’s Institute for Molecular Bioscience, said the team used biochemical and bioinformatics says the findings could be used to develop a new framework that might produce new painkillers. There are 25 known frameworks discovered over the past 25 years, many of which have already led to a drug or drug lead for several diseases.

“Cone snail venom is known to contain toxins proven to be valuable drug leads,” he said.

“This study gives the first-ever snapshot of the toxins that exist in the venom of a single cone snail.

“Cone snail venoms are a complex cocktail of many chemicals and most of these toxins have been overlooked in the past.”

“We expect these newly discovered frameworks will also lead to new medications, which can be used to treat pain, cancer and a range of other diseases.”

 

Sea Snails Paralyze Their Prey With Unique Type of Insulin

What do you do if you need to catch your own food… but you’re just not fast enough? That’s the problem cone snails had to face, and the solution they came up with is pretty amazing: they kill fish by lowering their sugar levels with a unique type of insulin, researchers found

Conus geographus, the cone snail used for this study.

Cone snails are found in marine environments. They are part of a large genus, and all the species from that genus are venomous capable of inflicting serious damage to humans; there have been many cases of divers being stung by cone snails, and even some lived were claims by the very powerful venom. Cone snails use a hypodermic-like modified radula tooth and a venom gland to attack and paralyze their prey before engulfing it. Their tooth is used like a dart or a harpoon, injecting the venom. But a group of researchers now believes we can actually use this venom for medical purposes.

The venom of cone snails contains hundreds of different compounds, and its exact composition varies widely from one species of cone snail to another. But they all have one thing in common – they kill fish by overdosing them with toxins.

“It looks like the fish is completely narced,” says Christopher Meyer, a cone snail specialist at the Smithsonian’s National Museum of Natural History, who wasn’t involved in the study.

When the insulin is injected into the prey, it causes the sugar levels to plummet, making the fish sluggish; once it gets slow enough, the snail closes in and injects another toxin which completely paralyzes them. The type of insulin they use for this is what scientists believe can be used.

“This is a unique type of insulin. It is shorter than any insulin that has been described in any animal,” Baldomero M. Olivera, a professor of biology at the University of Utah and a senior author of the study, said in a statement. “We found it in the venom in large amounts.”

In order to study this substance, researchers examined the gene sequences of all the proteins in the venom gland of Conus geographus, a cone snail with a very powerful venom. They detected two sequences which are similar to the insulin we humans use, but also spotted some differences. Studying it could provide new insight into how human metabolism works, and even help in concrete medical situations.

“The snail insulin consists of 43 amino acid building blocks, fewer than any known insulin. Its stripped down size and odd chemical modifications may have evolved as a way to make it better at causing hypoglycemia in prey,” the scientists said in the statement.

This is yet another proof that there are many secrets in the biological world still waiting to be discovered. The fact that this slow sea snail is able to develop such a complex chemical mechanism is truly spectacular.

“How brilliant is this,” says Meyer, who has observed a close cousin of the geographic cone snail—named Conus tulipa—hunting and killing fish in the same way in Guam. The fish almost look like they’re passed out drunk, he says, and now we know why.

Cone snail venom has also been proposed as a pain reliever and an antibiotic.

Journal Reference: Proceedings of the National Academy of Sciences.

 

 

ship-worm

Antibiotics of the future might come from the bottom of the oceans

The advent of antibiotics has spared humanity of a great deal of suffering and has saved countless lives through the years. Infectious diseases do not bore too easily and have always put out a fight, though. The bad news is that they’re winning and as the battle rages on, more and more strains become resistant to drugs. The consequences are broad and dire, and this is why scientists today want to be one step ahead and prepare for tomorrow.

Two separate studies recently published by a research partnership called the Philippine Mollusk Symbiont International Cooperative Biodiversity Group discuss how the future’s new class of antibiotics might reside at the bottom of the oceans. Like the name implies, both studies were concentrated on mollusks, a phylum of invertebrates which includes such animals as snails, clams and squid. Many of these ocean animals have been living in harmony with their bacterial companions for millions of years, and it’s in these bacteria that the key to the future’s antibiotics might lie. Having passed the test of time, rending no side effects to their animal companions, these bacteria have already shown promising results.

Ocean bacteria might be key to tomorrow’s antibiotics

ship-wormThe first study, published in the journal Proceedings of the National Academy of Sciences, the researchers tackled shipworms, but don’t let the name fool you too much. These mollusks have more to do with ships themselves than worms. Typically these are considered pests due to their ill-viewed habit of affixing themselves to the sides of wooden ships. Over time they feed on the wood, causing damage to the boat, which can be most unpleasant.

Then comes the question, however. How do these animals feed on wood? Wood is an extremely poor nutrient, far from being an ideal meal for a multicell organism, since it lacks proteins or nitrogen. Here’s the kicker though. The shipworm has a bacteria that converts the wood into a suitable food source where the animal can both live and feed. One such bacteria apparently also secretes a powerful antibiotic, which might hold great promise for combating human diseases.

“The reason why this line of research is so critical is because antibiotic resistance is a serious threat to human health,” said Margo Haygood, Ph.D., a member of the OHSU Institute of Environmental Health and a professor of science and engineering in the OHSU School of Medicine.

“Antibiotics have helped humans battle infectious diseases for over 70 years. However, the dangerous organisms these medications were designed to protect us against have adapted due to widespread use. Without a new class of improved antibiotics, older medications are becoming less and less effective and we need to locate new antibiotics to keep these diseases at bay. Bacteria that live in harmony with animals are a promising source. “

cone snailThe second paper, published in journal Chemistry and Biology, looked at cone snails collected in the Philippine. Previously, only a few studies actually were made to determine whether or not bacteria associated with these mollusks might prove useful in drug development. Mostly, this is due to the fact that cone snails aren’t that welcoming to outside visitors, featuring thick shells and quite a nasty toxic venom why they aren’t too shy about using. Since they pose a sort of miniaturized defense arsenal, it was previously assumed that these animals do not require additional chemical defense, meaning there could be no interest in human medication in turn. This was a false assumption.

Scientists proved that bacteria associated with cone snails actually produce a chemical which is neuroactive, impacting nerve cells (neurons) in the brain. Based on initial findings alone, the bacteria is already considered promising as a viable candidate for a highly powerful painkiller.

“Mollusks with external shells, like the cone snail, were previously overlooked in the search for new antibiotics and other medications,” said, Eric Schmidt, Ph.D., a biochemist at the university of Utah and lead author of the article.

“This discovery tells us that these animals also produce compounds worth studying. It’s hoped that these studies may also provide us with valuable knowledge that will help us combat disease.”