‘Cold’ genes linked to disease prevention

In the constant battle between humans and pathogens, a University of Victoria research team including Crystal L. Schmerk and Catharine M. Bosio is one step closer to finding a new defense against infection.

Properties of Arctic microbes may allow harmful bacteria to be killed at moderate temperatures

By Randy Boswell, Vancouver Sun – July 15, 2010

A team of Canadian scientists has exploited the heat-hating properties of several species of Arctic bacteria to develop potentially life-saving—and lucrative—methods of genetically re-engineering harmful germs for new vaccines and safer microbiology research labs.

The remarkable discovery, detailed in the latest edition of the Proceedings of the National Academy of Sciences, is described by the University of Victoria-led researchers as a possible breakthrough in preventing diseases such as tuberculosis and typhoid fever and in creating cheaper and more secure scientific facilities where risky bacteriological research is undertaken.

Among the Arctic microbes used in the B.C. team’s experiments is Colwellia psychrerythraea, a so-called “psychrophile” or a cold-loving bacterium that is known to leave a reddish tinge on the sea ice it sometimes inhabits in polar regions.

Another species used by the researchers, Shewanella frigidimarina, is described in the paper as coming from Arctic Ocean samples collected “near the northernmost point of Canada”—Ellesmere Island.

The scientists injected several “essential genes” from the cold-adapted organisms into more heat-loving, disease-causing germs, creating modified microbes that survived and reproduced in cooler conditions but quickly died at higher temperatures that would be found inside a human body or, in some cases, its warmer organs—such as the lungs.

Using the Arctic bacteria’s heat-sensitive traits to control when and where to trigger the deaths of harmful germs offers significant opportunities to develop new vaccines against various infectious diseases, the researchers state.

“Among the hundreds of psychrophilic bacterial species, there are undoubtedly numerous essential gene products that are inactivated at temperatures that are relevant to biotechnology applications,” the study states. “It is likely that a high proportion of newly found, temperature-sensitive essential genes could be used in any bacterium whenever there is a need to use heat to kill the bacterium at a moderate temperature.”

University of Victoria biochemist Francis Nano, one of five B.C. researchers who coauthored the study with a U.S. scientist, told Postmedia News on Wednesday that the team spent five years working on the project before hitting on the right combination of genetic traits to create viable organisms with a reliable, heat-triggered kill switch.

“People have been talking about using these cold-loving bacteria as sources of enzymes in laundry detergents that use cold water,” Nano said.

But the research team’s goal, he noted, is considerably more ambitious: To move the crucial traits of the Arctic bacteria “into some of the world’s most important pathogens” to combat fatal diseases around the world and to protect scientists from the “dangerous bacteria” they frequently handle in the name of medical research.

“The genes in our study fell apart between 33 and 37 degrees Celsius,” Nano stated in a summary of the study, “which means extraordinarily dangerous pathogens such as those that cause drug resistant staph infections, TB and even plague could be made inactive at body temperature and safe for vaccines and research.”

Nano said the team’s study has also illuminated the emerging importance of “bioprospecting” in the Arctic’s unique, organism-rich ecosystems, a field of scientific research and economic development in which Canada—despite its vast expanse of Arctic land and water—is falling behind more competitive polar nations.

He pointed to a 2008 UNsponsored report on Arctic bioprospecting that suggested Canada was not keeping up with countries such as the U.S., Russia and Norway in filing patents for biotechnology products derived from “Arctic genetic resources.”