21st CENTURY ALCHEMY
$1.9M NIH grant will allow researchers to explore how copper kills bacteria
With antibiotic resistance on the rise, a University of Arizona College of Medicine – Tucson laboratory is on a mission to discover new ways to neutralize harmful microorganisms.
University of Arizona Health Sciences
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University of Arizona Health Sciences researcher Michael Johnson, PhD, an associate professor of immunobiology, said he hopes his work on how copper interacts with bacteria could someday lead to a next-generation antibiotic.
view moreCredit: Photo by Nicole Swinteck, U of A College of Medicine – Tucson Department of Immunobiology
TUCSON, Arizona — A researcher at the University of Arizona College of Medicine – Tucson received a $1.9 million grant from the National Institutes of Health to continue his research into uncovering the mysteries of copper – specifically, how it can be harnessed to kill harmful bacteria and other microorganisms.
“We started using copper tens of thousands of years ago to cut down on bacterial infections,” said Michael D.L. Johnson, PhD, an associate professor of immunobiology. “People used to store their food in copper pots, which helped cut down on spoilage. Copper doorknobs have been shown to cut down on hospital-acquired infections. We’re still finding more things it can do.”
Johnson said he hopes one of these potential new uses could form the backbone of a next-generation antibiotic; however, to build a solid foundation for the pharmaceutical research, his lab aims to learn more about what makes copper toxic to bacteria in the first place. The research is being made possible by an R35 grant, which is reserved for scientists with outstanding research records and the potential to make major contributions to their fields.
Using Streptococcus pneumoniae as a model organism, Johnson and his team will attempt to learn what makes bacterial cells vulnerable to copper.
“It’s a pretty prominent pathogen. More than a million people die per year because of these bacteria,” he said, referring to the bacteria that can cause infections in the lungs, brain, nose and blood. “Our laboratory is interested in trying to figure out how it ticks. Our way of doing that is to understand how it gets its nutrition.”
The human body uses minerals such as iron and calcium, which we get from our diets, to keep bodily processes running. Bacteria are no different in that they need minerals to function, but copper, which is essential in the human diet, can be toxic to bacteria.
“There are certain minerals that bacteria don’t want in excess, and that’s where copper comes into play,” said Johnson, who is a member of the BIO5 Institute. “There are a lot of ways we can weaponize copper. We’re trying to study how our body uses copper as a mechanism to kill pathogens.”
Johnson believes that by flooding bacteria’s environment with excess copper, researchers may be able to trick them into building essential proteins with the wrong materials.
“Copper can displace iron, manganese or other metals and inactivate the protein,” he said. “It would be like me trying to start my wife’s car with my key. It doesn’t work.”
Johnson will build on his previous studies investigating how S. pneumoniae reacts to copper and complement parallel studies performed in his lab to learn more about copper as an antimicrobial. He said his goal is to untangle exactly what makes copper toxic to S. pneumoniae and use that information to draw conclusions about similar bacteria.
“All bacteria are different, but there are some mission-critical systems that are the same from bacteria to bacteria. How they process some of these metals is almost identical,” he said. “What I’m studying can be applied to other bacteria, but first we need to understand the basic mechanism of how these things work.”
Johnson said that while new antibiotics are slow to be developed and approved, antibiotic resistance is on the rise among pathogens, meaning that infections that were once easily cured with medicine could someday be deadly again. The Centers for Disease Control and Prevention considers antibiotic resistance a danger to public health, with drug-resistant S. pneumoniae classified as a “serious threat.”
“Bacteria are quite crafty. They will mutate to overcome antibiotics,” Johnson said.
“Our bodies have evolved to use copper to kill bacteria, and to this day, copper is still toxic. We want to take advantage of that to help people with life-threatening infections.”
This research is supported by the National Institute of General Medical Sciences, a division of the National Institutes of Health, under award no. R35GM128653.
Dangerous bacterial biofilms have a natural enemy
Discovery could help prevent infections
University of California - Riverside
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Microscopy images of bacteria strains, one, top, producing fimbriae as normal and one with high level of MEcPP unable to produce the fimbriae.
view moreCredit: Jingzhe Guo/UCR
If your teeth have ever felt fuzzy after skipping a brushing, you’ve encountered biofilm—a slimy bacterial layer that clings to surfaces. In medical settings, biofilms make infections harder to treat when they form protective shields for bacteria on devices like catheters and implants.
UC Riverside scientists have now discovered a chemical that plants produce when they're stressed prevents biofilm from forming. The breakthrough offers potential advances in healthcare as well as preventing equipment corrosion in industrial settings.
“In simple terms, biofilms are communities of microorganisms, like bacteria or fungi, that stick together and form a protective layer on surfaces,” said Katayoon Dehesh, distinguished professor of molecular biochemistry at UCR, and corresponding author of a study about the discovery.
“You’ve probably seen them as the slimy layer on river rocks or the plaque on your teeth. While they’re a natural part of many ecosystems, biofilms can cause big problems.”
The study, published in the journal Nature Communications, highlights the importance of a particular metabolite, which is a molecule produced during life-sustaining chemical reactions inside plants, as well as bacteria and even some parasites, like the one that causes malaria.
In plants, this metabolite, MEcPP, plays a critical role not only in producing essential compounds but also in stress signaling. For example, when a plant is damaged in some way and too much oxygen enters its cells, it accumulates MEcPP. This molecule then triggers protective responses within the plant. The researchers discovered that this same molecule has a surprising effect on bacteria like E. coli: it disrupts biofilm development by interfering with its ability to attach to surfaces.
In medical settings, biofilms grow on devices like catheters, stents, or implants, making infections harder to treat because the microbes in biofilms are highly resistant to antibiotics. In industrial contexts, they clog pipes, contaminate food processing equipment, and cause corrosion.
“By preventing the early stages of biofilm development, this molecule offers real potential to improve outcomes in any industries reliant on clean surfaces,” Dehesh said.
Bacteria rely on hair-like structures called fimbriae to anchor themselves to surfaces, a critical step in biofilm initiation. Fimbriae help bacteria latch onto medical implants, pipes, or even teeth, where they secrete a protective matrix that shields them from antibiotics and cleaning agents. Without fimbriae, biofilm formation cannot begin.
“Biofilms are like fortresses for bacteria,” said Jingzhe Guo, UCR project scientist and first author of the paper. “By disrupting the initial phase of attachment, MEcPP essentially disarms the bacteria’s ability to establish these fortresses.”
Through genetic screenings of more than 9,000 bacterial mutants, the research team identified a key gene called fimE, which acts as an "off switch" for fimbriae production. MEcPP enhances the activity of this gene and increases the expression of fimE. This, in turn, prevents the bacteria from producing fimbriae and forming biofilms.
“Our discovery could inspire biofilm prevention strategies across a wide range of industries,” Guo said. “From cleaner water systems to better dental care products, the possibilities are immense.”
Biofilms are not only a medical concern but also a costly problem in industrial settings. They contribute to clogged pipelines, corroded machinery, and contamination in food processing facilities. Traditional methods for managing biofilms often rely on harsh chemicals or expensive treatments, which can be harmful to the environment or ineffective over time as bacteria adapt.
“This study is a testament to the unexpected connections between plant biology and microbiology,” Guo said. “It’s thrilling to think a molecule that plants use to signal stress might one day help humans combat bacterial threats.”
Journal
Nature Communications
Article Title
An evolutionarily conserved metabolite inhibits biofilm formation in Escherichia coli K-12
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