SETI Is this an Europan?


Larry Klaes (lklaes@bbn.com)
Fri, 23 Jul 1999 19:01:23 -0400


http://news.bbc.co.uk/hi/english/sci/tech/newsid_399000/399972.stm

            Wednesday, July 21, 1999 Published at 15:21 GMT 16:21 UK

            Sci/Tech

            Toughest bug reveals
            genetic secrets

            Pyrococcus abyssi was found living in a deep-sea vent

            By BBC News Online Science Editor Dr David
            Whitehouse

            One of the hardiest microbes on Earth, Pyrococcus
            abyssi, has just had its entire genetic blueprint
            deciphered.

            P. abyssi was found in samples taken during a deep-sea
            expedition to a hydrothermal vent system. The genes
            which allow them to survive the extreme conditions could
            be of great use to bio-industry.

            The vents are some of the most inhospitable places on
            Earth. There is no sunlight, the temperature is over 100
            degrees Centigrade and the pressure is hundreds of
            times more intense than on the Earth's surface.

                             Vents are where
                             super-heated water squirts
                             out of the sea floor. The
                             geyser, full of chemicals and
                             minerals, is called a "black
                             smoker".

                             Towers and funnels grow
                             around the vent and are
                             home to some of the
                             strangest life forms on Earth
                             - blind shrimps, huge
                             tubeworms and many kinds
                             of micro-organisms.

                             Pyrococcus abyssi was
                             isolated from inside a vent
            3,500 metres (11,500 feet) below the ocean surface in
            the southwest Pacific.

            It likes conditions that the vast majority of other
            organisms would find impossible to live in. It thrives best
            at temperatures of about 103 degrees Centigrade and
            under pressures of about 200 atmospheres.

            Magic molecules

            An international team of scientists has just completed a
            map of the 1.7 million segments of its DNA, as part of an
            international effort to determine the genetic blueprints of
            organisms which live in unusual places.

            Scientists are very interested in such "extremophiles".
            Not only do they reveal that life can adapt to
            environments that were thought to be impossible but
            also because the molecular basis of that adaptation
            could provide industrial spin-offs.

            For example, in order to survive microbes like
            Pyrococcus abyssi have to have a sophisticated and
            robust DNA repair mechanism based on heat-stable
            enzymes.

            At such high temperatures the microbe's DNA
            undergoes continual damage and in order to survive that
            DNA must be repaired. The molecules that do this must
            be able to carry out their job without themselves being
            destroyed by the high temperature and pressure.



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