Fishy defence in cold storage

A scientist from the State University of New York has discovered a way to make large amounts of artificial antifreeze safe enough to use in living organisms.

A way to make large amounts of artificial antifreeze safe enough to use in living organisms has been developed by researchers looking at the ‘biological’ antifreeze used by Arctic and Antarctic teleost fish, according to a report in the September/October issue of Bioconjugate Chemistry.

The discovery may save fruit crops from frost or food from ‘freezer burn’.

A big problem with the freezing process in medical and industrial applications is that the formation of ice crystals damages living material.

Certain organisms like the fish, however, have developed a successful defence – a naturally produced antifreeze called antifreeze glycoprotein, or AFGP.

The biological AFGP in fish, and in some amphibians, plants and insects, prevents the growth of ice in those life forms, scientists have found.

While researchers have known about the glycoproteins for many years, they have been unable to produce large or stable enough copies for commercial applications, and the use of the natural compounds themselves is too labour and cost-intensive to be practical.

Even though researchers do not precisely understand the mechanism by which the AFGPs function, they have been able to modify the structure of the fish AFGP enough to build a longer lasting mimic according to Robert Ben, Ph.D., who led the research team.

Ben said the new method could easily produce large quantities of the compound that yield only to inhospitable conditions like extremely high or low temperatures.

The new synthetic proteins are said to be dramatically different from the natural antifreeze glycoprotein, but still display the ability to inhibit ice growth, said Ben. ‘This is very significant and may mean a real leap forward in the design of such compounds; we think this is incredibly promising for a number of applications.’

Potential uses for synthetic AFGP’s include a frost protection spray for crops that could expand growing seasons and even allow fruits to grow in more northern climates.

He also believes elimination of freezer burn is possible, along with the preservation of human organs and tissues for transplantation.

In essence, Ben reports, the new method replaces a weak chemical bond in the natural antifreeze with a far more durable one, but further study to develop greater strength in the artificial glycoprotein is ongoing.