Resurrected 160-million-year-old proteins show promise against drug-resistant bacteria

September 28, 2026 at 03:26 PM2 min

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University of Oregon biologists reconstructed antimicrobial peptides from extinct mammalian ancestors dating back 160 million years. Laboratory tests showed some resurrected peptides were more effective against drug-resistant bacteria than modern versions. The findings, published in PLOS Biology on Aug. 25, suggest ancient immune defenses could inspire new treatments for antibiotic-resistant infections.

Key Facts

Researchers reconstructed antimicrobial peptides from extinct mammalian ancestors dating back as far as 160 million years.
Some resurrected peptides outperformed modern versions against drug-resistant bacteria in laboratory experiments.
The study was published in PLOS Biology on Aug. 25.
Lactoferrin, the protein central to the research, emerged around 160 million years ago near the end of the Jurassic Period.
Lactoferrin is present in breast milk, tears, saliva, snot, and intestinal mucus, but not blood.

Ancient Antimicrobial Defense

About 160 million years ago, near the end of the Jurassic Period, the common ancestor of all placental mammals appeared. Around that same time, lactoferrin, the protein at the center of the research, also emerged. Lactoferrin is an immune protein present in almost every body fluid except blood, including breast milk, tears, saliva, snot, and intestinal mucus. One of its primary jobs is to keep iron away from pathogens by binding tightly to the element, making it harder for microbes to access. Lactoferrin also contains an antimicrobial peptide capable of damaging bacterial membranes, creating holes that can rupture the cells.

Evolutionary Reconstruction

Close relatives of lactoferrin do not share this bacteria-killing ability, suggesting the trait appeared sometime after lactoferrin emerged during mammalian evolution. To determine when the ability developed and how it changed over time, the team retraced lactoferrin's evolutionary history and reconstructed versions belonging to its extinct ancestors. Laboratory experiments showed that some reconstructed peptides from extinct ancestors were more effective against drug-resistant bacteria than some versions found in modern species. Matt Barber, senior author of the study and an evolutionary biologist at the UO College of Arts and Sciences, said these long-lost biological defenses could give researchers useful starting points for developing treatments that complement or replace antibiotics that no longer work.

Therapeutic Potential

Antimicrobial peptides are a key part of the body's first line of defense, according to 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. Barber said the team is interested in whether resurrecting or engineering enhanced antimicrobial peptides could be used as therapeutics down the road. The revived proteins could provide scientists with new ideas for treating antibiotic-resistant infections, which have become a major global health challenge.