Low levels of nitric oxide gas can prevent and kill disease-causing bacteria by tricking them into thinking their time is up, according to scientists from the Environmental Biotechnology Cooperative Research Centre (EBCRC) and the University of New South Wales.
"We have found that nitric oxide causes bacterial cell death and dispersal that makes them more vulnerable to antibacterials and biocides," says UNSW microbiologist Staffan Kjelleberg.
Bacteria such as those in dental plaque and slime in backyard pools protect themselves from attack by forming defensive colonies called biofilms.
"We have found a way to trick the bacteria from re-forming into biofilms by using very low concentrations of the chemical nitric oxide," says Professor Kjelleberg.
"When bacteria disperse they are very vulnerable to attack by bactericides, chemicals and other organisms that live off bacteria, such as protozoans. Another big advantage of nitric oxide is that it means we could use lower concentrations of antibacterials and biocides, which is a win for the environment."
"Biofilms - or films of bacteria - form on nearly every surface that has fluid flowing over it, be it the ocean, your bloodstream or the fluid in your lungs. Sometimes biofilms are beneficial but more often they promote diseases such as cholera, cystic fibrosis and other bacterial diseases. They are responsible for 60 percent of human infections," says Professor Kjelleberg.
Biofilms are a challenge to disease prevention because they make bacteria highly resistant to conventional antibacterial chemical treatments such as those in biocides and antibiotics. This leads to significant costs to industry and government in are as such as agriculture, aquaculture and other marine industries, water supply and wastewater treatment.
The bacteria in a biofilm disperse once they reach a mature stage of development or when they are under attack," says Professor Kjelleberg who, with colleague Professor Peter Steinberg, discovered in the 1990s how to prevent biofilms forming by "jamming" bacterial signalling systems with natural compounds called furanones.
Professor Kjelleberg sees limitless applications for nitric oxide in healthcare, bio-security, agriculture and industrial applications such as water quality and wastewater management.
About Nitric Oxide
The discovery of the biological functions of nitric oxide only 25 years ago came as a surprise to science.
Named "molecule of the year" in 1992 by the journal Science, nitric oxide's extraordinary range of biological properties only came to light in the 1980s. In 1998 Ferid Murad, Robert F. Furchgott, and Louis Ignarro were awarded the Nobel Prize in Physiology or Medicine for discovering the signalling properties of nitric oxide. It's estimated that 3,000 scientific articles about the biological roles of nitric oxide are published annually.
It plays a role in blood circulation, the nervous system and the development and maintenance of erections.