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DISCOVERIES

Textbook theory for life's origins might be wrong

CHEMISTRY
A renegade theory on the origins of life gained credence last week when German researchers announced a successful recreation of the conditions they say did the trick four billion years ago.

According to senior author Gunter Wachtershauser, who proposed the so-called "iron-sulfide world" theory in 1988, simple gases like nitrogen and carbon dioxide that arose from the magma of ancient volcanoes interacted with minerals like iron and nickel sulfides to form the building blocks of proteins. The minerals, found in deep-seated rock, then interacted with these protein building blocks to speed up the production of proteins, leading eventually to more-and-more-complex living elements. Recreating this mix of gases and metals in the laboratory over several days, Wachtershauser's team not only found such building blocks but also discovered there are multiple chemical routes to make them. The prevailing textbook theory suggests that RNA and DNA precursors in a primordial soup were activated by lightning to eventually give rise to cells. Wachtershauser said his model requires only simple chemicals, known to be present four million years ago, and the chemical energy in the minerals. "We work on a much simpler level," he said. "We locate the origin of life, the first reproducible and evolvable origin, at the level of the formation of simple organic compounds from inorganic starting materials. That's the trick."

BOTTOM LINE: There's more evidence for life starting small, with the formation of simple organic chemicals.

CAUTIONS: A crucial component of the hypothesis -- the ability of the building blocks to facilitate their own production, thereby beginning life -- is still only theoretical.

WHAT'S NEXT: Wachtershauser hopes to catch the building blocks, which include amino acids, in the act of facilitating their own production.

WHERE TO FIND IT: Science, Oct. 27

ISHANI GANGULI

VACCINES

Children may be able to escape a few needle jabs


Prevnar, a vaccine used to reduce pneumococcal disease risk in children, is effective with fewer doses than currently recommended, a new study finds. Pneumococcal diseases include pneumonia, meningitis, ear infections, blood stream infections, and sinusitis. In 2000, US doctors began giving children Prevnar on a four-dose schedule at two, four, six, and 12 or 15 months of age. To study Prevnar's effectiveness, Dr. Cynthia Whitney at the US Centers for Disease Control and Prevention and colleagues looked at 782 children with severe pneumococcal disease and 2,512 healthy children between ages 3 and 59 months. Some were on the four-dose schedule, others received fewer doses because of a vaccine shortage, and some had never been vaccinated. The researchers found that one or more doses reduced risk of severe pneumococcal disease in healthy children by 96 percent and by 81 percent in children with other chronic medical conditions.

BOTTOM LINE: "The vaccine provides protection against severe disease in children younger than 5, even with less than recommended doses," said Tamar Pilishvili, of the CDC, one of the study's authors.

CAUTIONS: The study assesses the effectiveness of Prevnar in preventing severe disease -- meningitis, blood stream infections, and severe pneumonia -- but not its effectiveness in less severe cases like ear infections and mild pneumonia.

WHAT'S NEXT: Many developing countries are not introducing the vaccine because of the prohibitive cost of four doses. Researchers now hope to urge such countries to introduce the vaccine on a less-than-four-dose schedule.

WHERE TO FIND IT: Lancet, Oct. 28

SENA DESAI GOPAL

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