Category Archives: Medical and Science Issues

Crocodiles, Alligators, and The Amazing Anti-Bacterial Agents in Their Blood

Saltwater crocodile

Alligators often engage in violent fights over territories and mates, and scientists  have puzzled over why their wounds rarely get infected.  Now researchers think the secret lies in the reptiles’ blood. Chemists in Louisiana found that blood from the American alligator can successfully destroy 23 strains of bacteria, including strains known to be resistant to antibiotics.  In addition, the blood was able to deplete and destroy a significant amount of HIV, the virus that causes AIDS.

Study co-author Lancia Darville at Louisiana State University in Baton Rouge believes that peptides—fragments of proteins—within alligator blood help the animals stave off fatal infections.  Such peptides are also found in the skin of frogs and toads, as well as in Komodo dragons and crocodiles. The scientists think that these peptides could one day lead to medicines that would provide humans with the same antibiotic protection.

“We are in the process of separating and identifying the specific peptides in alligator blood,” said Darville, who presented the findings on Sunday at the 235th national meeting of the American Chemical Society in New Orleans.

“Once we sequence these peptides, we can obtain their chemical structure to potentially [create new] drugs.”

Alligator Cream

Study co-author Mark Merchant, a biochemist at McNeese State University in Lake Charles, Louisiana, was among the first to notice alligators’ unusual resistance.  He was intrigued that, despite living in swampy environments where bacteria thrive, alligators that suffered frequent scratches and bruises rarely developed fatal infections.  Merchant therefore created human and alligator serum—protein-rich blood plasma that has had clotting agents removed—and exposed each of them to 23 strains of bacteria.

Human serum destroyed only eight of the bacterial strains. But the alligator serum killed all 23, including drug-resistant bacteria such as MRSA (methicillin-resistant Staphylococcus aureus).  When the alligator serum was exposed to HIV the researchers found that a good amount of the virus was destroyed.

The study team thinks that pills and creams containing alligator peptides could be available at local pharmacies within seven to ten years. Such products would be a boon to patients that need extra help preventing infections, such as diabetes patients with foot ulcers, burn victims, and people suffering from auto-immune diseases.  But there may be potential hurdles before alligator-based medicines can reach drugstore shelves.  For example, Darville noted, initial tests have revealed that higher concentrations of the alligator serum tend to be toxic to human cells.

Not So Primitive

Adam Britton is a biologist based in northern Australia who has found similar antimicrobial proteins called crocodillins in the blood of crocodiles.

Antimicrobial peptides in crocodiles and alligators are part of the animals’ innate immune systems, Britton said, which provide automatic protection from certain diseases.

By contrast, human immunities are adaptive—people develop resistance to many diseases after exposure, such as the low doses given in vaccines. Although innate immunity is often considered primitive, there is nothing primitive about its effectiveness, Britton said.

Innate immunities “usually serve to amplify the adaptive immune system, often by weakening the membranes of bacteria,” he said.

“It appears that alligator and crocodile antimicrobial peptides are extremely effective agents” against bacteria, he added.

Britton hopes to use Australian crocodile blood to complement the latest work on alligators and answer questions about what these proteins mean for immune systems in general.

“If we can harness these secrets,” Britton said, “we could be on the verge of a major advance in medical science.”

Amitabh Avasthi
National Geographic News, April 7, 2008



DNA of Western Painted Turtle May Lead to Treatments for Stroke and Hypothermia in Humans

Photo by Lynnette Schimming
Photo by Lynnette Schimming

By Dene Moore

VANCOUVER – Scientists have decoded the DNA of the Western painted turtle, and hope that unravelling the mystery of the reptiles may lead to medical breakthroughs for humans.

They are the most abundant turtle in North America, with a northernmost range from Ontario west to British Columbia, where they are listed as endangered on the Pacific Coast and of special concern in the rest of the province.

The shelled reptile, named for the bright yellow stripes that adorn its body, is a fresh water species that can freeze solid and return to life when thawed.

It can also hold its breath for up to four days at room temperature without suffering oxygen deprivation and up to four months when hibernating, said Brad Shaffer of UCLA’s Institute of the Environment and Sustainability and one of the lead authors of the study published in the latest edition of the journal Genome Biology.

“Those are fascinating ecological, physiological features that have evolved in turtles … so as a biologist those are fascinating things to learn more about, more about the genes that allow them to do that,” Shaffer said.

Shaffer and his colleagues hope solving the DNA puzzle may one day lead to innovations in treating hypothermia, frostbite, heart attacks or strokes.

The DNA confirmed for scientists that the turtles have evolved at a … turtle’s pace, and have in fact changed little in design over the past 210 million years.

“Turtles are nothing short of an enigma,” Richard K. Wilson, director of Washington University’s Genome Institute and one of the authors, said in a statement. “We could learn a lot from them.”

In addition to their ability to freeze and thaw without suffering organ or tissue damage, they have longevity and continue to reproduce at advanced ages, he said.

Western painted turtles can live for more than 40 years, while other species of turtle live well over a century. Females can grow up to 25 centimetres long, while males grow up to 17 centimetres.

The DNA information — funded by the National Human Genome Research Institute at the National Institutes of Health in the United States — is being shared with 59 scientists around the world, including three researchers at UBC, Carlton and the University of Toronto who will study the DNA.

There are 330 turtle species, and about half are considered threatened due largely to their popularity as a food dish in Asia, where lore says eating turtles promotes good health and long life.

Schaffer said he hopes the potential for medical advances might help save turtles.

“They’re fascinating in their own right just as examples of unique biodiversity. They’re important in terms of what they might say in terms of human health and welfare, and over half of them are threatened with extinction right now,” he said.

“One of the messages of all this fascinating biology we’re learning about is how important it is to preserve the little bit of turtle biodiversity that we have.”

Source:  Canadian Press

Reconstructive Surgery for Injured Crocodile at Kovai Zoo, India

The mugger crocodile (Crocodylus palustris) (literally "crocodile of the marsh"), also called the Indian, Indus, Persian, or marsh crocodile, is found throughout the Indian subcontinent and the surrounding countries.
The mugger crocodile (Crocodylus palustris) (literally “crocodile of the marsh”), also called the Indian, Indus, Persian, or marsh crocodile, is found throughout the Indian subcontinent and the surrounding countries.

March 2013.

A female crocodile at the Coimbatore VOC Zoo, which lost a portion of its lower jaw three years ago, is all set to undergo reconstruction surgery.

The mugger crocodile was brought to the zoo from the Amaravathi Dam, near Udumalpet, in 1987.  It was severely injured by other crocodiles and was unable to eat properly, causing its growth to be stunted.

Zoo director Dr. Asokan said experts from the Crocodile Specialists Group, Hong Kong, were contacted for consult. No similar procedure has been performed in India and the zoo authorities also consulted human dentists for input.

Dr. Rajkumar, a Coimbatore-based dentist, and Dr.  Senthil, an oral and maxillofacial surgeon, developed a plan to fix titanium plates onto the lower jaw of the crocodile with screws.

“Titanium is biocompatible, which means that it is non-toxic, and will not be rejected by the body,” said Dr. Senthil.  Tissues located around the jaw of the crocodile will be grafted over the plate, he said.

“The plates will be able to withstand the pressure when the crocodile chews. When the crocodile bites, the pressure will be equal to 5,000 pounds of weight bearing down,” he said.

The crocodile will be kept in isolation after the surgery for a few months to allow it to heal.

“The plates will have to be specially designed. The surgery will take around three to four hours, and we hope to do it soon,” said Dr. Rajkumar.

The procedure is not without risk. Colin James Stevenson, director of the Madras Crocodile Bank Trust, said a similar surgery attempted in the United States was not successful.

“There are not many cases where such surgery has been done. We will have to see how the crocodile responds to the surgery,” he said.