This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: University of Oregon biologists have resurrected prehistoric proteins up to 160 million years old that carry natural antimicrobial properties. The revived molecules could inspire the design of new treatments for antibiotic-resistant infections, a pressing global health issue.
Described in a paper published in PLOS Biology on Aug. 25, the scientists worked their way up the tree of life, reconstructing peptides—short protein fragments—dating back to the earliest placental mammals, the diverse lineage that includes humans and nearly all mammals alive today. In laboratory tests, the researchers found that some of the extinct peptides were more potent against drug-resistant bacteria than some of their present-day counterparts. Evolution's ancient remedies could offer new starting points for scientists designing treatments that supplement or replace antibiotics that no longer work, said Matt Barber, senior author of the paper and evolutionary biologist at the UO College of Arts and Sciences.
"For anybody who studies pathogenic bacteria, it's always in the back of our minds that antibiotics are one of the most important breakthroughs in medicine in the 20th century," Barber said. "But bacteria are, and have been for a long time, evolving resistance to them." He continued: "We're definitely interested in whether by resurrecting or engineering some enhanced antimicrobial peptides, we could use these as therapeutics down the road." Some 160 million years ago, near the end of the Jurassic Period, the ancestor of all placental mammals, whose young develop in the womb, emerged—and so did lactoferrin, the protein at the center of Barber's investigation. Lactoferrin is an immune protein found in nearly every body fluid except blood: breast milk, tears, saliva, snot and intestinal mucus.
Its main function is to withhold iron from pathogens. Bacteria in the body need iron to fuel their advances, but lactoferrin acts as a vault, tightly sealing the key resource away. In addition to securing iron from bacterial reach, lactoferrin has evolved built-in tools to fight pathogens.
Most notably, it has an antimicrobial peptide that punches holes in bacterial membranes, rupturing the cells. "Antimicrobial peptides are a key part of the body's first line of defense," said Titas Sil, lead author of the paper and a doctoral student in Barber's lab. "They can target a broad range of pathogens, and due to their potency, scientists have been trying to synthesize a variety for therapeutic uses." None of lactoferrin's close protein relatives have that bacteria-killing ability, suggesting that the property arose sometime after lactoferrin emerged in the mammalian lineage.
To find out when and how it has evolved since, the researchers worked backward through its evolutionary history and resurrected its ancestors. A look at the past might give ideas for a healthier future, Barber said. "Evolution is essentially a science experiment billions of years old, right?" he said.
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