NEWS OF THE WEEK
change its ‘feed in tariff’ policies,” says iSuppli photovoltaics industry analyst Henning Wicht. Last fall, Spain decided to cap the amount of new solar energy generation capacity that it is willing to subsidize. Separately, New Energy Finance reported last month POLYSILICON: Expansion takes that the price of polysilicon for solar wafers is half of place amid softening demand what it was just one year ago. The firm, a provider of market intelligence on the energy industry, noted that further price reductions are likely. APAN’S TOKUYAMA has firmed up plans to spend Tokuyama says it expects that supply and demand $680 million on a plant on the island of Borneo will be in balance by the time it opens the Borneo facilthat will produce polysilicon ity in 2013, a prediction seconded for use in solar cells. The capacity of by iSuppli. “Polycrystalline silicon FORECAST RESET the plant is twice what the company for solar cells is expected to enjoy Change in Spain’s subsidy envisioned when it announced the high-level growth over the medium program will curb growth in expansion just a few months ago. to long term,” according to a statesolar-panel demand Tokuyama’s move comes as inment from Tokuyama. The plant dustry analysts report a softening in will have an annual production caSolar-panel production, gigawatts 25 ■ New estimate the market for solar cells, whether pacity of 6,000 metric tons. ■ Estimate before 20 Spain’s policy change based on silicon wafers, which are Located near the city of Kuching, made from polysilicon, or on thinin the Malaysian part of Borneo, the 15 film silicon. California-based iSupsite Tokuyama selected for its new 10 pli, an electronics market research plant has access to ample industrial 5 firm, is warning of a serious overwater and electrical power. The comsupply in the solar energy market. pany, one of the world’s top silicon 0 2008 09 10 11 12 13 “The solar industry in 2009 has producers, currently produces only been undermined by a collapse in Yamaguchi, Japan. Tokuyama’s NOTE: Estimates for global crystalline and thin-film solar-panel production. Previous in demand due to the decision by lack of expansion in recent years has forecast did not extend to 2013. Spain—which accounted for 50% of cost it market share, according to SOURCE: iSuppli worldwide installations in 2008—to iSuppli.—JEAN-FRANÇOIS TREMBLAY
TOKUYAMA DOUBLES OUTPUT
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INTERFERING WITH PAINKILLERS PHARMACOLOGY: Gut microbes
manipulate acetaminophen metabolism
OSO3– p-Cresol sulfate
B
ESIDES HELPING US digest food, the bacteria
living in our gut produce chemicals that interfere with how we process the common painkiller acetaminophen. This new finding suggests that bacterial chemicals may be interfering with other drugs as well— for good or for bad. Every person’s gut has a unique assortment of trillions of microorganisms, from thousands of different species, that together produce a cornucopia of molecules in the gut, including p-cresol (C&EN, July 20, page HN 43). To see whether p-cresol and its metabolites could influence acetaminophen metabolism, Jeremy K. Nicholson of Imperial College London, in collaboration with scientists from Pfizer, took urine samples from humans before and after taking the painkiller (Proc. Nat. OSO3– Acad. Sci. USA, DOI: 10.1073/pnas.0904489106). Acetaminophen sulfate They found that the bacterial p-cresol competes
Human sulfonation machinery modifies p-cresol from gut bacteria preferentially over acetaminophen. O
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with acetaminophen for O-sulfonation in the liver. The more p-cresol there is, the less acetaminophen gets sulfonated. Because sulfonation facilitates acetaminophen’s excretion through urine and thus mitigates the drug’s liver toxicity, the team’s results show that chemicals produced by a person’s gut flora actively interfere with acetaminophen metabolism. O-Sulfonation also helps other drugs work optimally, as in the case of minoxidil, which was originally used to treat high blood pressure and is now prescribed to counteract balding. It can also cause unwanted side effects for some medications, including the breast cancer drug tamoxifen. “Variation in gut bacteria may therefore account for differences in the ability of the liver to metabolize certain drugs,” comments Paul Watkins, director of the Institute for Drug Safety Sciences, a collaboration between the Hamner Institutes for Health Sciences and the University of North Carolina, Chapel Hill. p-Cresol is just one gut-flora by-product, and sulfonation is just one route by which humans metabolize drugs. With trillions of bacteria in our gut, there may be many more microbial compounds that interfere with many more drug metabolism pathways, Nicholson suggests. Assessing the effects of gut microbe activity “should be an integral part of pharmaceutical development and personal health care,” he adds.—SARAH EVERTS
AUGUST 17, 2009
