Dorothy Paramore Highly Commended Award

Melissa Lyne of the University of Tasmania won the Dorothy Paramore Highly Commended Award for her story on the biomedical benefits of coral reef organisms. Ms Dorothy Paramore is an artist who donated the proceeds from the sale of a painting from her Great Barrier Reef Series to benefit a student studying the reef.

Possible human health benefits from research into the environmental adaptations of bacteria that colonise on corals of the Great Barrier Reef.

By Melissa Lyne

It is hoped that current research into the environmental adaptations of coral reef organisms may have significant biomedical implications in providing humans with the benefit of greater health in old age.

Humans have long sourced marine products for medicinal and health purposes. In many cultures, women and men smear their bodies in algae or seaweed to eliminate toxins from their bodies. Also, the omega-3 oils found in some seafoods can aid in the prevention of many health disorders, including some forms of cancer. It’s even been debated that on an island off the coast of Japan, the drinking water, which is high in fossilised coral minerals, may aid in prolonging life.

The Great Barrier Reef is one of the seven natural wonders of the world and is home to thousands of species of plants and animals. Reefs are mass deposits formed by the growth and reproduction of the marine animal known as coral. The Great Barrier Reef contains about 400 species of coral. These corals have adapted to living in tropical conditions and in shallow waters, where they are exposed daily to high levels of ultra-violet (UV) radiation.

Australian Institute of Marine Science (AIMS) Principal Research Scientist Dr Walt Dunlap has spent 23 years studying the photobiology of marine organisms of the Great Barrier Reef.

In his latest research, Dunlap discovered an unusual adaptation of specific bacteria that exist on the surface of corals of the Great Barrier Reef. He believes that this discovery may one day enable humans to enjoy greater health in old age and help to prevent the onset of degenerative conditions such as Alzheimer’s and Parkinson’s disease.

While exposure to UV rays is harmful to humans, these marine bacteria have adapted a way to prevent such harm.

“Our work on marine bacteria, with potential application to human ageing, commenced in 2001 on the discovery that bacteria exposed to high levels of environmental radiation [protect themselves from] damage by increasing the anti-oxidant form of coenzyme Q”, Dunlap says.

A coenzyme is a substance that helps enzymes to function – effectively increasing the rate at which chemical reactions take place in living organisms. Coenzyme Q is used to treat a number of diseases and disorders, such as Chronic Fatigue Syndrome and has recently been utilised for commercial skincare products. As a powerful anti-oxidant, the reactive form of the coenzyme helps to combat free radicals - toxins that damage living cells.

A common way that free radicals are generated is during exposure to UV radiation (photooxidative stress). Preventing this form of generation of free radicals involves the presence of adequate levels of the reactive form of coenzyme Q.

The ability to maintain adequate levels of coenzyme Q decreases with age. This, coupled with the accumulation of oxidative damage to living cells and tissues, not only leads to the development of disorders and degenerative diseases, but also accelerates the ageing process.

In initial collaborative studies at the University of Tokyo in early 2001, cultures of marine bacteria were exposed to UV light to enhance oxidative damage.

Dunlap theorised that by subjecting the bacteria to photooxidative stress, levels of the reactive form of coenzyme Q would diminish by the consumption of free radicals.

Unexpectedly, the opposite was discovered. Dunlap found that under UV exposure, the level of the reactive (antioxidant) form of coenzyme Q increased by more than 200 per cent. This overcompensated for UV exposure and prevented damage to the organisms.

A research team was then sent to the Great Barrier Reef in early January 2002, to isolate, and later culture, specific ‘UV-extremophilic’ bacteria.

“[We found that] these bacteria turn on a biochemical pathway for recycling the metabolic activity of coenzyme Q … in response to oxidative stress,” Dunlap says.

“We know they are activating the reductive enzyme that accomplishes this, but we don't yet know the precise biochemical events that regulate this activity.”

Dunlap labels this activity a ‘novel adaptive response’, but hopes that it can be utilised as a model towards developing anti-ageing and disease preventative therapeutics.

Mitochondria are known as the powerhouses of living cells and Dunlap says because of the functional similarity between mitochondria and bacteria, the ability of tropical marine bacteria to increase enzyme activity is a vital discovery in exploring metabolic pathways of antioxidant defence for humans.

Collaborative research conducted at the Osaka City University Medical School found that exposing mammalian cells to UV radiation did not generate the same response as was discovered in UV-adapted marine bacteria.

In marine bacteria the reductive enzyme that recycles the active form of coenzyme Q increases its own activity by more than 1200 per cent under photooxidative stress.

“We are [hoping] to find the biochemical ‘switch’ that activates the regenerating coenzyme Q enzyme and the molecular signal that ‘toggles’ the switch,” Dunlap says.

“Having found this we then want to design a mimetic drug based on the molecular ‘toggle’ of marine bacteria to activate the human equivalent of this enzyme,” he says.

“The aim is to devise a supplement to sustain metabolic health in aging and reduce the risk of late-onset degenerative disease - a major objective in preventative medicine.”

Dunlap’s current work is partly related to his earlier discovery of ‘coral sunscreen’.

During the 1980s he and other scientists speculated that corals were using a biochemical form of sun protection. “Corals are animals, but they lack a protective coating such as feathers, scales and hair,” Dunlap says.

He found that corals protected themselves from UV damage through a natural UV absorbing ‘coral sunscreen’.

The discovery of ‘coral sunscreen’ and its consequent benefits for humans further demonstrates the uniqueness and importance of marine research.

With a worldwide patent to develop a synthetic version of the ‘coral sunscreen’, Sydney-based Sunscreen Technologies expects to have products using the compound on the market in 2004.

Globally, biotechnology products in 2002 were valued at more than $US 200 billion.

Marine biotechnology is a particularly unique field in itself – early marine organisms were the first to develop aerobic metabolism and protection against oxidative damage.

Recently, AIMS received renewed Federal Government funding for its marine biotechnology research in serving the National Research Priorities.

“Our initiatives to develop frontier technologies from marine science, while conducting environmental research to sustain our marine natural resources, [are] drawing appreciation,” Dunlap says.

Dunlap says he may not personally be able to reap the benefits of his own discovery and research in his own lifetime, as it is hard to predict how quickly his anti-ageing research will progress.

“Much will depend on [finding the] molecular mechanism … that bacteria are using to regulate coenzyme Q … activity,” he says.

He anticipates this will eventually lead to the creation of a molecular mimic for enhancing enzyme and coenzyme activity for human benefit.

“Regardless, we will uncover much new and interesting science along the road of discovery.”

Dr Walt Dunlap is working in collaboration with scientists both in Australia and overseas on this novel enzyme adaptation of UV-extremeophilic bacteria. While his studies focus on marine photobiology and environmental biochemistry, Walt also has a background in biomedical research – he was a postdoctoral research fellow at the John Curtin School of Medical Research at the Australian National University. During his current 23-year career with AIMS, he has worked worldwide in various environmental conditions, studying marine photobiology in the polar region of Antarctica under the ‘ozone hole’, to where he studies now – in the marine tropics of the Great Barrier Reef.