Israeli Researchers Discover Tiny Toads Wield ‘Deadly Weapon’ Against Bacteria

Technion researchers are part of an international team that found an amazingly powerful anti-bacterial chemical on a tiny Australia toad.

By Yakir Benzion, United With Israel

Researchers at Israel’s Technion are leading an international team, including scientists from Germany and Spain, that discovered tiny Australian toads have chemicals on their skin that act as powerful fighters against bacterial infections.

In non-technical terms, the researchers found that the goo oozed through the skin of those little Aussie toadlets may be a key in developing new methods of fighting bacteria.

The toadlets secrete something called peptide uperin 3.5 that is benign until it encounters bacteria, when it rapidly changes into a form that affects the bacterial membrane and kills the bacteria.

By way of background, a peptide is a short chain of amino acids, which are connected to one another in a sequence by molecular bonds called peptide bonds. And amino acids? They are organic compounds that combine to form proteins. Basically, amino acids are the building blocks of life.

The researchers discovered that the specific peptide on the toadlets turns on and off as part of the critter’s immune system. They found that the peptide self-assembles into a unique structure that can change its form in the presence of bacteria to protect the toadlet from infections.

The researchers are excited because it shows unique atomic-level evidence explaining a regulation mechanism of an antimicrobial peptide.

In practical terms, this discovery about the toadlet’s skin could provide insight into human neurodegenerative diseases, such as Alzheimer’s and Parkinson’s.

Deadly Weapon Against Bacteria

The findings suggest that the antibacterial peptide secreted on the toadlet’s skin acts as a weapon held in reserve that can be activated when bacteria are present. Once the peptide encounters the bacterial membrane, it changes its molecular configuration to a form that the researchers realized is a deadly weapon against bacteria.

“This is a sophisticated protective mechanism of the toadlet, induced by the attacking bacteria themselves,” said biologist Prof. Meytal Landau, the lead author of this study, adding it is a unique example of the toad’s evolutionary design to produce a molecule that can switch itself on, when needed, to heal from a bacterial attack.

There’s lots of potential for future medical applications. While antimicrobial peptides are found in all forms of life and are thought to be commonly used as weapons in nature, even sometimes killing cancer cells, the unique properties of the toadlet’s antibacterial peptide shed light on their potential use in the fight against neurodegenerative and systemic disorders.

The researchers hope that their discovery can be used to develop synthetic antimicrobial peptides that would be activated in the presence of bacteria. These synthetic peptides could also serve as a coating for medical devices or implants, or even in industrial equipment that requires sterile conditions.

This little Australian toad’s technical name is the West Kimberley Toadlet (Uperoleia mjobergii). It is also known as the Mjöberg Toadlet after Swedish explorer Eric Georg Mjöberg, who led an expedition to northern Australia in the early 1900s. Mjöberg identified the species of tiny toads that grow to a maximum of 25 mm (one inch) long, proving again that big things can come in small packages.