Bacteria Use Amyloids as Molecular Armor
Microbial Wars: Bacteria Forge “Armor” from Alzheimer’s-Linked Protein
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Boulder, CO – In a discovery that blurs the lines between microbial defense and human disease, researchers have found that some bacteria are using a protein similar to those implicated in Alzheimer’s disease as a formidable shield against predators. This “suit of armor,” made of amyloid protein called curli,offers robust protection and could hold keys to combating antibiotic resistance and neurodegenerative disorders.
The Discovery of Bacterial Armor
The groundbreaking research, led by the University of Colorado at Boulder, began with an unusual experiment. Scientists collected a diverse array of E. coli strains from various global sources, including the digestive tracts of lizards, a patient’s urinary tract in Sweden, and scat samples from leopards and kangaroos. These bacteria were then exposed to Bdello, a predatory bacterium known for its ability to consume other bacteria.
“We were blown away,” said Professor Robin Whiteley, a lead researcher on the project. “We found that about one-third of the strains were actually resistant to Bdello.”
Unveiling the Protective Mechanism
Using advanced microscopy,the team observed how these resistant E. coli strains defended themselves.The images revealed that the bacteria were coating themselves entirely in curli, a type of amyloid protein. While similar to the amyloids associated with alzheimer’s disease, curli are not identical.
Further genetic sequencing studies confirmed that bacteria utilize curli not only against Bdello but also as a defense mechanism against a broader spectrum of predatory bacteria.
“We contend that the same characteristics that make amyloids a problem for humans-the fact that they are durable and hard to break down-make them an ideal suit of armor for bacteria, which they use to defend against a wide range of threats,” Whiteley explained.
Amyloids: A Double-Edged Sword
The study also suggests a crucial role for amyloids in the formation of biofilms. These resilient layers of bacteria, often found on medical instruments, implants, and industrial machinery, are notoriously difficult to eradicate and are a meaningful source of persistent infections and material corrosion.
Currently,the primary method for removing biofilms is physical scraping. Though, Whiteley hypothesizes that Bdello and other predatory bacteria may possess genetic tools or specialized enzymes capable of breaking down this rigid amyloid shield.”Wherever organisms are fighting, there is biochemical innovation happening,” he noted.
Implications for Human Health
The research team is now focused on identifying these “shield-busting” tools. Their ultimate goal is to harness this knowledge to develop novel strategies for combating antibiotic resistance and treating amyloid-related diseases like Alzheimer’s.
“If we can understand what makes this armor so durable and what some predatory bacteria are doing to circumvent it,it could have all sorts of implications for human health,” Whiteley stated. by observing the ongoing “duels” between bacteria in the environment, scientists hope to unlock new avenues for therapeutic intervention.
Source: University of Colorado at Boulder
Journal Reference: Kidney, He, et al. (2025). Functional amyloid proteins confer defense against predatory bacteria. Nature*. doi.org/10.1038/s41586-025-09204-7