In a Dragon’s Blood, Scientists Discover a Potential Antibiotic - via Herp Digest

New York Times by DONALD G. McNEIL Jr. APRIL 17, 2017

 

Biochemists may have discovered a type of antibiotic that sounds like something out of a fairy tale: It is based on dragon blood.

Scientists from George Mason University recently isolated a substance in the blood of a Komodo dragon that appeared to have powerful germ-killing abilities.

 

Inspired by the discovery, they created a similar chemical in the lab and dubbed it DRGN-1.

Tests on mice that were given skin wounds infected with two types of bacteria showed that DRGN-1 had three valuable properties: It punched holes in the outer membranes of both gram-negative and gram-positive bacteria, it dissolved the biofilms that glue bacteria together, and it sped skin healing.

The researchers’ study was published last week in the journal Biofilms and Microbiomes. 

The work was paid for by the military’s Defense Threat Reduction Agency, but the discoverers are now seeking drug-industry backing, too.

The race to find new antibiotics has taken on great urgency as more and more bacteria develop resistance to existing drugs. In February, the World Health Organization ranked the most dangerous superbugs, calling for new tools against them.

The study’s lead authors, Monique L. Van Hoek and Barney M. Bishop, study crocodilians and monitor lizards like the dragon because they can survive grievous wounds, including lost limbs, in filthy environments without getting infected.

It is unclear how dragons kill prey, Dr. Bishop said. They have serrated teeth and their mouths teem with bacteria, so it was long believed that sepsis caused by the bacteria weakened their larger victims, like deer.

But in 2009 Australian researchers discovered that the dragons also inject a shock-inducing venom.

Because Komodo dragons are endangered and considered divine in their native Indonesia, the researchers had to find one that lived in a zoo and was under the care of keepers brave enough to take blood samples without anesthesia.

At the St. Augustine Alligator Farm and Zoological Park in Florida, they found Tujah, a 100-pound male whose keepers distracted him while about four tablespoons of blood was taken from his tail.

“No dragons were harmed in this process, and we won’t be creating dragon farms to bleed them,” Dr. Bishop said.

Tujah’s blood is a “rich source” of potential antibiotics. Dr. Van Hoek and her colleages are testing more than 40 other substances isolated from it.

Wild dragons might have even more defenses against infection, but the researchers said they were unlikely to find out.

“I wouldn’t turn down wild dragon blood if it was sent to me and I thought it was collected ethically,” Dr. Bishop said. “But I’m not going to go out in the wild to try to get it.”

Antimicrobial substances identified in Komodo dragon blood

Date: February 22, 2017

Source: American Chemical Society

In a land where survival is precarious, Komodo dragons thrive despite being exposed to scads of bacteria that would kill less hardy creatures. Now in a study published in the Journal of Proteome Research, scientists report that they have detected antimicrobial protein fragments in the lizard's blood that appear to help them resist deadly infections. The discovery could lead to the development of new drugs capable of combating bacteria that have become resistant to antibiotics.

The world's largest lizard, Komodo dragons live on five small islands in Indonesia. The saliva of these creatures contains at least 57 species of bacteria, which are believed to contribute to the demise of their prey. Yet, the Komodo dragon appears resistant to these bacteria, and serum from these animals has been shown to have antibacterial activity. Substances known as cationic antimicrobial peptides (CAMPs) are produced by nearly all living creatures and are an essential part of the innate immune system. So, Barney Bishop, Monique van Hoek and colleagues at the College of Science at George Mason University wondered whether they could isolate CAMPs from Komodo dragon blood, as they previously had done with alligator blood to expand the library of known CAMPs for therapeutic studies.

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Biologists use fossils to pinpoint when mammal and dinosaur ancestors became athletes

December 22, 2016

Many mammals and birds are remarkable athletes; mice work hard to dig burrows for protection and sparrows fight gravity with each flap of their wings. In order to have the energy to sustain vigorous exercise, the body's tissues need a steady supply of oxygen, and red blood cells (RBCs) are the center of the oxygen delivery system. Size matters, too; athletic mammals and birds have much smaller RBCs than other vertebrates with lesser capacities for exercise. Biologists have long been puzzled over the evolutionary origins of RBC size. Were predecessors of mammals and birds—including dinosaurs—athletes and did they have tiny red blood cells? How do you measure the blood of extinct animals?

Now, biologists at the University of Utah and the Natural History Museum of Utah have established a 'fossilizable' indicator of athleticism in the bones of extinct vertebrates.

The study, which published online in Current Biology on Dec. 22, is the first to draw a link between RBC size and the microscopic traces of blood vessels and bone cells inside the bone. The researchers measured the bony channels that deliver oxygen to bone tissue to pinpoint when our mammal ancestors, bird and dinosaur predecessors evolved small RBCs. They found that extinct mammal relatives, or cynodonts, and extinct bird relatives had smaller RBCs and were likely better athletes than earlier terrestrial vertebrates. The timing of RBC-size reduction coincided with the greatest mass extinction event on Earth 252 million years ago, an event that paved the way for the age of the dinosaurs.

"Some people look at fossils, and they see rocks—but these were living and breathing organisms. To be able to find proxies that tell us something like this, it gets us to think about living organisms in their environments," says lead author Adam Huttenlocker of the Keck School of Medicine at the University of Southern California, who completed the research as a postdoctoral fellow at the U and THE MUSEUM. "It allows us to think about the overall implications for mass extinction. What were some of the physiological innovations that allowed them to be successful? That's really exciting."

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Gator blood contains natural germ fighters - via Herp Digest

Posted By Science Codex February 12, 2015 

Sophisticated germ fighters found in alligator blood may help future soldiers in the field fend off infection, according to new research by George Mason University.

The study, published Feb. 11 in the scientific journal PLOS One, is the result of a fundamental research project supported by the Defense Threat Reduction Agency (DTRA) to find bacterial infection-defeating compounds in the blood of the crocodilian family of reptiles, which includes American alligators.

The project is about to start its fourth year and has received $6 million in funding to date from DTRA. If fully funded over five years, the project will be worth $7.57 million.

Alligators live in bacteria-filled environments and dine on carrion. Yet this ancient reptile rarely falls ill.

"If you look at nature, sometimes we can find pre-selected molecules to study," says study co-author Monique van Hoek. "I was surprised to find peptides that were as effective as they are in fighting bacteria. I was really impressed."

Discoveries made by George Mason's 17-member, multidisciplinary research team could eventually find their way to the battlefield to protect warfighters from wound infections and potential exposure to biothreat agents. Researchers believe this work could benefit civilians too.

"We hope that these could be the basis to develop new treatments," says van Hoek, a professor in the School of Systems Biology and the National Center for Biodefense and Infectious Diseases at Mason.

Exploiting innate immunity

Van Hoek and lead co-authors Barney Bishop and Joel Schnur from the College of Science suspected the germ-fighting ability could be in the form of antimicrobial peptides. These very small proteins are part of the innate immunity of alligators and even humans; all higher organisms make antimicrobial peptides.

"It's that part of your immune system that keeps you alive in the two or three weeks before you can make antibodies to a bacterial infection," van Hoek says. "It's part of your generalized immune response to the world."

Peptides are more general in their activity than antibodies, which are made to fight infections by specific bacteria or viruses.

"Innate immunity may work less well than antibodies, but it works well enough," van Hoek adds. "The reason why we're so interested in them: they are part of nature's way of dealing with the onslaught of bacteria and viruses that we face every day. Every breath that you take, every thing that you eat, you're constantly exposed to bacteria and your body needs to fend them off in some way."

Alligator blood samples were provided by Kent Vliet of the University of Florida and the St. Augustine Alligator Farm Zoological Park in St. Augustine, Fla., which has a wide variety of reptiles, including all 23 species of crocodilians.

Bishop says he was surprised at the sophistication and diversity of the alligator's germ-fighting peptides. These reptiles have evolved with a formidable defense against bacterial infections.

The Mason team took an innovative approach in its study of the alligator blood samples. Bishop developed custom-made nanoparticles to preferentially capture the peptides out of the very complex mixture of proteins and peptides in alligator plasma.

This process revealed an unexpected result--the identified potent germ-fighting peptides were only fragments of larger "parent" proteins, says Bishop, who's also a professor in the Department of Chemistry and Biochemistry.

The custom-made particles used in this project significantly shortened the number of steps required to capture and identify peptides that were present in alligator blood plasma.

The Mason team has other reptiles to tackle. As part of the DTRA grant called "Translational Peptide for Personal Protection," Mason researchers also will study Siamese crocodiles, Nile crocodiles and gharials.

And they've learned a thing or two along the way about these ancient reptiles.

"You stay away from the business end," Bishop jokes.

Citation: Bishop BM, Juba ML, Devine MC, Barksdale SM, Rodriguez CA, et al. (2015) Bioprospecting the American Alligator (Alligator mississippiensis) Host Defense Peptidome. _______________________________________

Vampire bats' blood diet leads to loss of bitter taste

By Zoe GoughReporter, BBC Nature

Vampire bats' strict blood diet has made them lose much of their ability to taste bitter flavours, a study has found.

Bitter taste acts as a natural defence against eating poisonous foods and was thought to be indispensable in animals.

Researchers say the bats' special diet and use of smell, echolocation and heat could have made taste less important.

Their work shows poor bitter taste is more widespread in animals than previously thought.

The findings are reported in the journal Proceedings of the Royal Society B.

Toxins typically taste bitter to animals but bottlenose dolphins and some whales have been shown to have reduced bitter taste, probably because they swallow their food whole, making taste unnecessary.

Vampire bats are the only mammals to feed solely on blood meaning they are unlikely to encounter toxic foods in the wild. The research team wanted to find out if that had left them with a lack of bitter taste.

Continued