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.
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