Mushrooms, the smallest rooms in the world, have already proved to be healthy foods.   Scientists have now genetically modified mushrooms such that they might serve as bio-factories for the production of various beneficial human drugs, according to new research released Friday June 22, 2007.

"There has always been a recognized potential of the mushroom as being a choice platform for the mass production of commercially valuable proteins," said Charles Peter Romaine, who holds the John B. Swayne Chair in spawn science and professor of plant pathology at Penn State.

"Mushrooms could make the ideal vehicle for the manufacture of biopharmaceuticals to treat a broad array of human illnesses. But nobody has been able to come up with a feasible way of doing that."

Dr. Romaine and Xi Chen have developed a technique to genetically modify Agaricus bisporus -- the button variety of mushroom, the predominant edible species worldwide.

Using the technology, transgenic mushrooms may be used as bio-factories to produce therapeutic proteins such as vaccines, monoclonal antibodies and hormones like insulin or commercial enzyme such as cellulase for biofuels, which if produced from other sources have been known to be of low efficiency.

"Right now medical treatment exists for about 500 diseases and genetic disorders, but thanks to the human genome project, before long, new drugs will be available for thousands of other diseases," Dr. Romaine said.

"We need a new way of mass-producing protein-based drugs, which is economical, safe, and fast. We believe mushrooms are going to be the platform of the future."

To create transgenic mushrooms, what researchers did was insert a gene that confers resistance to an antibiotic known as hygromycin in circular pieces of bacterial DNA called plasmids, which have the ability to multiply within a bacterium called Agrobacterium.

When the gene was successfully inserted and functional, the transgenic mushroom cells show resistance to hygromycin, a property helping researchers to sort out the transgenic mushroom cells from the non-transgenic cells, Dr. Romaine explained.

If a second gene for something like insulin were to be patched in the plasmids, that gene would be expressed along with the antibiotic resistant gene.

"There is a high probability that if the mushroom cell has the hygromycin resistance gene, it will also have the partner gene," Dr. Romaine added.

The efficiency of producing a targeted drug through the transgenic mushrooms depends upon many factors, but the researchers hope that the process can potentially produce drugs faster and cheaper compared to the conventional technologies.

"With mushrooms, we can use commercial technology to convert the vegetative tissue from mushroom strains stored in the freezer into vegetative seed. A crop from which drugs may be extracted could be ready in weeks," Dr. Romaine said.

The use of the mushroom technology does not require expensive infrastructure, he added.