Eugene, Oregon: Scientists at the University of Oregon have reconstructed antimicrobial proteins from mammalian ancestors that lived as far back as 160 million years ago, discovering that some of the ancient molecules can attack disease-causing bacteria and, in certain laboratory tests, outperform corresponding modern human peptides.

Researchers Looked Back 160 Million Years

The research focused on lactoferrin, an immune protein found in humans and many other mammals. Besides helping restrict bacteria’s access to iron, lactoferrin contains a short antimicrobial peptide capable of damaging bacterial membranes.

Researchers used a technique called ancestral sequence reconstruction to work backward through evolutionary history and estimate the genetic sequences of extinct mammalian ancestors. They then synthesized the predicted sequences and produced the corresponding proteins in laboratory cells.

Ancient Peptides Tested Against Modern Bacteria

The reconstructed peptides were tested against several bacteria associated with human disease, including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Streptococcus species.

The oldest reconstructed peptides could damage bacterial membranes, but some bacteria were able to repair the damage. Peptides from more recent mammalian ancestors became progressively more effective, with some showing greater activity than modern human versions in laboratory experiments.

One Small Genetic Change Made a Big Difference

One of the notable findings was that a relatively small change in the peptide’s amino-acid sequence could substantially increase its antimicrobial activity.

Researchers identified a single mutation that contributed significantly to the increased potency observed during the evolutionary history of the molecule.

The finding suggests that studying how natural immune defenses changed over millions of years could provide clues for designing new antimicrobial compounds.

Could Help Fight Antibiotic Resistance

Antibiotic-resistant bacteria are making some conventional treatments increasingly difficult to use. Scientists are therefore investigating alternative approaches, including antimicrobial peptides that attack bacteria in different ways.

The Oregon research does not produce a new antibiotic immediately, but it provides an evolutionary blueprint that researchers could potentially use when designing or modifying antimicrobial molecules for future therapies.

Ancient Molecules Are Not Yet Medicines

Researchers caution that the resurrected peptides are not ready to be used as medicines.

Compared with conventional antibiotics, these molecules can be less structurally stable and may be rapidly broken down inside the body. Additional research would be required to determine whether modified versions could eventually become safe and effective treatments.

Evolution as a Source of Drug Ideas

The study demonstrates how evolutionary history can function as a source of biological information for modern medicine.

Instead of searching only among existing organisms, scientists can reconstruct molecular characteristics that existed in extinct ancestors and investigate whether those characteristics could provide useful solutions to present-day medical problems.

Researchers say understanding how antimicrobial peptides evolved could also help scientists anticipate how bacteria might develop resistance to future peptide-based treatments.

A New Direction in Antimicrobial Research

The findings add to growing research into alternatives and supplements to traditional antibiotics.

The next challenge is determining whether the promising laboratory activity of these ancient peptides can be translated into stable, safe and effective therapeutic molecules. For now, the work offers a new example of how evolutionary biology and modern biotechnology can be combined to explore potential strategies against drug-resistant infections.