Single-celled organisms that live in extreme environments such as boiling hydrothermal pools could be an overlooked source of antibacterial drugs.
The family of life forms, dubbed Archaea, live in environments that are too treacherous for most organisms to survive, Vanderbilt University reported.
"It is the first discovery of a functional antibacterial gene in Archaea," said Seth Bordenstein, the associate professor of biological sciences at Vanderbilt University who directed the study, "You can't overstate the significance of the antibiotic resistance problem that humanity is facing. This discovery should help energize the pursuit for new antibiotics in this underexplored group of life."
A past study found the source of a gene that produces a type of enzyme found in tears, saliva, milk and mucus was Archaea. The group of organisms is believed to have spread the antibacterial property to other species.
"We found that this Archaea lysozyme kills certain species of firmicutes bacteria, a large group of bacteria that contains the classic drug resistant bacterium Staphylococcus aureus, Bacillus anthracis, which causes anthrax, and the gut infection Clostridium difficule," Bordenstein said.
In recent years researchers have found these bacteria can co-exist with other organisms and live outside of their normal extreme environments. This means they are competing for resources and creating chemicals to attack and defend against other organisms; these compounds could be used as drugs that kill bacteria that have already become resistant to our typical antibiotics. The antibacterial gene, dubbed GH25-muramidase, was found to be present in lineages of plants and fungi as well.
"That was completely unexpected," said co-author Jason Metcalf. "But the weirdest occurrence was in an Archaea species Aciduliprofundum boonei that lives in hydrothermal vent communities. Why in the world would it need such an enzyme?"
To make their findings the researchers purified A. boonei's GH25-muramidase domain, which allowed them to determine the enzyme's function.
"How do Archaea do it?' Through this paper, we show that the smart archaeal 'bugs' do so by stealing genes from their bacterial 'mates' and competitors. This points to Archaea being good, as yet relatively untapped targets for exploring new antibacterial drugs," said Professor Anna-Louise Reysenbach from Portland State University in Oregon.
