Crustacean disease breakthrough

The Fish Site
by The Fish Site
25 April 2007, at 1:00am

US - A breakthrough by a James Cook University researcher has closed the gap on the development of a disease-fighting tool in crustaceans that has eluded scientists for decades.

The results of 'Advances in Crustacean Cell Culture', a research study done by PhD student Kerry Claydon, have scientists one step closer to creating a crustacean cell line.

The cell line, a permanent cell system contained in a bottle, could help wipe out deadly viruses infecting crustaceans and save the world's aquaculture industry from millions of dollars in losses.

There are currently no treatments available for viruses in crustaceans so when even one animal becomes infected, the virus can spread rapidly, causing devastation to the industry.

In 1987-88 the prawn aquaculture industry in Taiwan was hit by a virus reducing the country's 115,000 tonne industry to 44,000 tonnes.

"That's a 62% loss caused by a single viral agent," JCU's School of Veterinary and Biomedical Sciences Kerry Claydon said.

"A similar thing happened again in China in 1993-94. Their industry suffered a 58% loss.

"When you consider that 50% of the world's population obtain their protein sources from seafood, the industry cannot afford to incur such massive losses," she said.

In 2006 the aquaculture industry celebrated a significant milestone. For the first time in history, the aquaculture industry out-produced wild caught fisheries.

"We certainly cannot afford something like what happened in Taiwan or China to continue to occur," Ms Claydon said.

"We need to develop a more sensitive system to study crustacean viruses, so we can improve the way viruses interact within the cellular environment and eventually work on preventative measures to stop infection from occurring."

The development of a cell line will help scientists better understand viruses affecting crustaceans and provide a more sensitive and reliable diagnostic tool, which will not only standardize the system for disease analysis, but also minimize animal experimentation.

The first human cell line was produced in 1952, with the first invertebrate cell line coming ten years later. The first aquatic invertebrate (crustacean) cell line was attempted in 1986; however, all efforts to date have been unsuccessful.

"This is not due to lack of trying. In the past seven years alone, there have been over 100 published reports, but not a single one has been developed into a permanent cell line.

"With this in mind I still decided to go ahead with the project because I believed there had to be a way. The task could not be impossible," Ms Claydon said.

Ms Claydon's three year PhD project was split into three stages. During the first two she investigated whether the difficulty with developing a crustacean cell line was due to the external environment in which they were cultured.

During this time, she developed a more specialised culture media that increased the longevity of the cells in culture.

The breakthrough for the project; however, was in the third stage, when Ms Claydon successfully 'transfected' (introduced foreign DNA) cells taken from the Australian red claw crayfish (Cherax quadricarinatus) with human cancer genes.

This important advancement brings researchers close to producing 'immortal' cells (or tumour cells), which would be capable of indefinite replication and thus form the first permanent crustacean cell line.

In the meantime Ms Claydon will be at Brunei's Department of Fisheries, where she has secured a top job with consultancy firm Integrated Aquaculture International as Director of Shrimp Pathology.