COURTESY OF NED SHAW (BOTH)
NEWS OF THE W EEK
ORIGIN-OF-LIFE SAMPLES REVISITED PREBIOTIC CHEMISTRY: Famous spark-discharge experiments produced more amino acids than reported
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N THE QUEST TO understand how life on Earth became possible, Stanley L. Miller conducted a set of “primordial soup” experiments in the early 1950s to synthesize amino acids, the basic building blocks of peptides, proteins, and nucleic acids. The famous experiments, part of his doctoral thesis at the University of Chicago, mimicked possible stormy atmospheric A reddish polymer conditions on ancient Earth. and solution In a new twist involving the experiments, a team were produced in including Adam P. Johnson of Indiana University, JefMiller’s first set of experiments in 1953. frey L. Bada of Scripps Institution of Oceanography, and Antonio Lazcano of the National Autonomous University of Mexico uncovered some of Miller’s original samples and reanalyzed them. They found that one particular variation of the spark-flask apparatus experiments produced a wider variety of amino acids—research that Miller never published (Science 2008, 322, 404). The sample vials were discovered by chance, team leader Bada says. Miller once had mentioned to Lazcano that he had saved extracts from his experiments. Lazcano later passed that tidbit to Bada. “I realized I had these samples in my lab, Samples from Miller’s 1953–54 sparkbecause I inherited all the material flask experiments; some solution from from Miller’s lab and office,” says each run was saved in glass vials.
Bada, who was Miller’s second graduate student. Miller had suffered a stroke and was unable to provide any details about the samples or why he never published the additional results, Bada adds. “But when he died in May 2007, we decided to take a careful look at what we had.” In the original experiments, Miller produced an electric discharge between two electrodes protruding into a flask containing a gaseous mixture of methane, ammonia, hydrogen, and water. Scientists who have analyzed Miller’s experiments doubt that the highly reducing reaction conditions he used existed on early Earth. But one set of experiments with a modified apparatus set up to simulate more intense conditions of a lightning-laced volcanic eruption was more intriguing, Bada says. Miller identified five amino acids and detected others in his reported experiments. But with modern liquid chromatography and mass spectrometry techniques at their disposal, Bada and coworkers identified 14 amino acids and five amines in those samples and a richer collection of 22 amino acids and the five amines from the unpublished volcanic experiments. “The volcanic apparatus experiment suggests that, even if the overall atmosphere was not reducing, localized prebiotic synthesis could have been effective,” the researchers write. They speculate that amino acids formed in volcanic island systems could have been polymerized by carbonyl sulfide—a volcanic gas—to form peptides leading to proteins. “Miller’s experiments transformed the study of the origin of life into an important research field,” comments astrochemistry specialist and NASA project scientist Pascale Ehrenfreund of Leiden University, in the Netherlands. Being able to reanalyze 50-year-old residues with modern equipment “is an exciting adventure,” Ehrenfreund says. The newly identified compounds will certainly be the basis for further studies on prebiotic chemistry, she adds.—STEVE RITTER
POLLUTION IN CHINA Residents oppose another p-xylene project Opposition to a plan to build a petrochemical complex equipped with an aromatics unit is mounting—in cyberspace so far—in Taizhou, an industrial city south of Shanghai. Taizhou is home to numerous chemical plants and already suffers from heavy pollution. Although the project is still in the early stages of planning, city residents have posted numerous protests on electronic bulletin boards. Many of the messages on the most active site (bbs.taizhou. com) call on local government officials to extensively consult the public before construction starts.
Taizhou residents are particularly incensed that the multi-billion-dollar project will include a 2.4 million-metric-ton-peryear plant for p-xylene, a polyester raw material. Other components of the complex, according to the Chinese media, are an oil refinery and a 2.4 million-metric-ton ethylene unit. None of the three firms reported to be behind the project—PetroChina, its parent China National Oil Corp., and Shell—have confirmed their involvement. This is the third project featuring a pxylene unit to be challenged in China in the past two years over health and pollution concerns. In coastal Xiamen, middle-
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class protesters stopped the planned construction of a p-xylene unit near the city center last year (C&EN, June 11, 2007, page 17). And in March, violent protests against a p-xylene unit took place in Fujian province (C&EN, March 10, page 15). Kenji Otsuka, an expert in Chinese rural development at the Institute of Developing Economies, in Chiba, Japan, figures that Taizhou officials remain optimistic about the project’s success. But from what has happened in other parts of China, he says, the project could be abandoned if online protests turn into real ones.—JEAN-FRANÇOIS TREMBLAY
