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Monday, 2 October, 2000, 21:10 GMT 22:10 UK
First salt-loving bug sequenced
Salt flats University of Leicester
Salt flats at Lake Magadi, Kenya. The flats are red due to the proliferation of Halobacteria.
Scientists have sequenced the genome of the first salt-loving extremophile, a micro-organism that can survive in conditions 10 times saltier than seawater.

The genetic data will shed light on how these primitive organisms are able to thrive in extreme environments like salt mines or salty lakes.

Ultimately, researchers hope to harness the bug's genetic secrets for use in biotechnology, for example to develop rice that grows in salty soil.

The information might also be used to investigate whether inhospitable planets like Mars once harboured similar lifeforms, as well as gaining a deeper understanding of how life arose on Earth.

Ancient relics

The micro-organism is a species of Halobacterium - microscopic, rod-shaped organisms found in very salty lakes, including the Great Salt Lakes and the Dead Sea.

Halobacteria, like all extremophiles, are members of an unusual group of bacteria-like organisms called the archaea.

Archae appeared early in the course of biological evolution. Some scientists believe those in existence today represent relics of ancient forms of life.

A few other extremophiles, mainly the types that can survive in hot springs, have already been sequenced.

But this is the first salt-loving micro-organism for which the genome has been cracked.

Shotgun method

An international team of researchers from 11 universities in North America, Canada and the UK sequenced the DNA in the bug known as Halobacterium NRC-1.

They utilised a "shotgunning" technique similar to that used by Dr Craig Venter to sequence the human genome.

The micro-organism was found to have more than 2,500 putative genes, about a third of which are novel and have never previously been reported.

Professor Shiladitya DasSarma, of the University of Massachusetts, Amherst, who led the team, said: "Genome studies on Halobacterium should contribute toward some of the greatest unsolved mysteries of biology today, including our understanding of evolution as well as of the fundamental life process in higher cells.

"There is a tremendous genetic resource in the genomes of micro-organisms. In fact, it is one of the last, largely untapped, natural resources on our planet."

Harnessing nature

One such application is in the field of biotechnology, said Professor Michael Danson, director of the Centre for Extremophile Research at the University of Bath, UK, where some of the work was carried out.

"Most biological material is extremely fragile," he told BBC News Online. "Most technological processes are very harsh.

"One way to resolve that potential problem is to go to biological material which is naturally very stable, from organisms that grow in very harsh or extreme environments.

"The big power of these extremophiles is that they have components which should be naturally suited to use in biotechnology."

Bill Grant, Professor of Environmental Microbiology at Leicester University, UK, said the genome sequence of Halobacterium will enable researchers to work out strategies that might allow other organisms to live in high-salt environments.

"There is a basic problem in a lot of areas of the world with salinisation of soils," he said.

"By looking at an organism like this that has the capacity to survive under these conditions you might be able engineer in mechanisms so that rice would grow under much saltier conditions than it can do at the moment."

Space research

The new gene sequence will also be of use to scientists who are investigating whether extremophiles could have colonised space.

Professor Danson said there was a good chance that there might have been crystalline salt or even underground water on Mars. "There are many people who think that understanding these extreme halophiles will help us to detect if there are organisms on Mars that could well be halophilic in nature," he said.

"By understanding halophiles and extremophilic life on this Earth, we may be in a much better position to detect life which is either living, or has lived, on other planets."

The Halobacterium NRC-1 research is published in the Proceedings of the National Academy of Sciences.

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