When Genes Go Bad Addiction

EDITORIAL What’s on the Label? hen you are buying food, are you one of the 30% of shoppers (an estimate in the United Kingdom) who always read the labels, or one of the 20% who rarely or never give them a glance? Do you know what to make of them if you read them? Labels are meant to inform you and to help you to choose. But when you go shopping, how much time do you have to read about the differences between 30 types of chicken soup or 300 varieties of breakfast cereal? Consumers seem to want more and Wmore choice, and consumer pressure groups definitely want more information on food labels. Choice and information are also attractive to regulators, because these options are less likely to be viewed as restricting individual freedom or stifling food industry innovation than the alternative of regulating food content. In the United States, labeling regulations are largely about the material content. In Europe, the method and place of production may also be specified in law, even if they make no material difference to the contents. This difference in approach is evident in the labeling of genetically modified (GM) foods. Whether the plant from which a food is made is GM is irrelevant in the United States, given its emphasis on overall content rather than process. But in Europe, labeling of foods containing DNA or protein from GM plants is mandatory, and legislation has now been extended to include purified derivatives such as glucose syrup and canola oil (but not products from animals fed on GM animal feed or products made with GM technology, such as cheese). Transatlantic differences in food labeling are also apparent when it comes to the biggest current challenge for food policy: obesity. Doing something about obesity is especially difficult for governments and regulators, because diet and lifestyle are in the territory of personal freedom, not state intervention. At the same time, the health care costs are potentially huge, so the pressure for action is on. The blend of action that is emerging, in both Europe and the United States, includes voluntary changes by the food industry, public education, and better labeling. Some countries and U.S. states are going even further; for instance, by restricting what can be sold in school vending machines and restricting television advertising. All of these changes are meant to make it easier for people to choose a healthy diet. The world’s fattest nation, the United States, has what is arguably the best nutrition labeling, with a mandatory nutrition facts panel. So would better labeling help? The largest food retailer in the United Kingdom, Tesco, has said that it plans to test a “traffic light” system, using red, yellow, and green colors to give consumers simple information about the main nutrients. Some object to this because of the potential implication that there are good (green) and bad (red) foods, whereas the traditional mantra from nutritionists is that there are only good and bad diets. But the food/diet distinction has changed as many people rely increasingly on ready-made meals or snacks. Research in the United Kingdom suggests that people would actually favor a simple sign-posting system such as traffic lights. The food industry is responding to public interest in diet and health by making foods that claim to have specific health benefits. These come close to the border between food and medicine. You can buy cholesterol- reducing margarine, eggs that contain long-chain omega-3 unsaturated fatty acids, and yogurts that claim to help you balance your gut flora. The U.S. Food and Drug Administration has a three-tiered system for such health claims, depending on the strength of the evidence for the claim. The European Union does not have specific regulations, but plans to introduce rules within the next 2 years that will require the independent evaluation of health claims by the European Food Safety Authority. The implications of science-based regulation are enormous for the worldwide food industry, both because products that claim to improve your health are generally highly profitable and because, in the science of nutrition, there is often disagreement among experts. Over the next decade, increases in our understanding of the relationship between an individual’s genetic makeup and his or her nutritional needs will open up a whole new area for debate about what goes on the label. The world of choice is not going to get any easier. John Krebs John Krebs is chairman of the Food Standards Agency, UK. CREDIT: RED/GETTY IMAGES PHOTODISC www.sciencemag.org SCIENCE VOL 306 12 NOVEMBER 2004 1101 Published by AAAS H IGHLIGHTS OF THE RECENT LITERATURE EDITORS’ CHOICE edited by Gilbert Chin CELL BIOLOGY Endocytosis at the Hub In clathrin-mediated endocytosis, a network of proteins assembles on the cytoplasmic surface of the plasma membrane and promotes the pinching off of a membrane-bounded clathrin-coated vesicle. Together, the proteins select cargoes that are car- ried either inside the vesicle or in its membrane, modify the shape of the membrane, and drive invagination, vesicle scission, and eventual uncoating. A key player in this process is the AP2 clathrin adaptor protein, which is involved in concentrating selected cargo in the newly forming clathrin-coated pits. In protein interaction networks, hubs are proteins that have dispropor- tionately high numbers of interaction partners; in biological processes, hubs provide a temporal or spatial ordering to protein interactions. Praefcke et al. treat clathrin-mediated endocytosis as a module of a network and show how the α-appendage part of the AP2 protein works as an interaction hub. Only after being concentrated at sites of endocytosis do the appendages provide a multivalent binding platform (hub) for interaction partners (i.e., endocytic cargoes or other cargo adaptors). Thus, the partners will then be represented according to their relative affinities and concentrations in endocytic clathrin-coated pits and vesicles, even though any individual interactions will have been transient. — SMH EMBO J. 10.1038/sj.emboj.7600445 (2004). Interacting partners. APPLIED PHYSICS those regions that are buried To assess the amount of IMMUNOLOGY Registering under several layers of epitaxially clathrate stored and to Three in One grown semiconductor material. evaluate its stability, Buffett Nanostructures Ruess et al. have used a registra- and Archer developed a Vaccines are designed to The manipulation of atoms tion technique that allows the mechanistic model for generate robust immunity using scanning tunneling alignment of macroscopic clathrate dynamics based on through the coactivation of microscopy (STM) has long electrodes to the nanoscale experimental and theoretical the adaptive and innate arms promised the ability to fabricate device elements buried under- data on its stability and on of the immune system. This is nanometer- and atomic-scale neath. The registration markers factors affecting its formation achieved by steering tripartite electronic device structures. are etched into the substrate and release, such as the responses to antigenic epitopes However, the realization of before the STM manipulation supply of carbon to sediments by helper T (TH) cells, antigen- presenting dendritic cells Registration markers stage and so should be a and its diagenesis, storage, 1969 (2004) Buried nanostructure general method for bottom-up and oxygen content. (DCs), and antibody-producing 4, . 24nm epitaxial fabrication of other nanoscale Application to the current B cells or the cytotoxic silicon device structures. — ISO ocean basin implies that the lymphocytes (CTLs) that Nano Lett. 4, 1969 (2004). ultimately execute pathogen Contact leads global inventory is on the 18 clearance. However, the poor ET AL., NANO LETT order of 10 g of carbon 25 µm GEOLOGY stored as methane gas and inherent immunogenicity of clathrate. The modeling peptide epitopes favored in Si substrate Taking Inventory results imply that increasing some vaccine formulas dictates Schematic showing An enormous amount of temperature would likely the need for including complex contacts (yellow) to a buried methane, an important green- deplete this inventory and potentially toxic adjuvants 90-nm-wide quantum wire. house gas, is stored in considerably; rebuilding that stimulate the essential sediments in the ocean basins would take several million priming activity of DCs. robust devices has been a as icy methane clathrate and years. The model also reveals Jackson et al. have refined difficult goal to attain simply as gas trapped by this ice and that unless the oxygen this approach by synthesizing because of the engineering by sediments. Catastrophic content of the deep oceans structures containing TH . RUESS 10.1038/SJ.EMBOJ.7600445 (2004)(BOTTOM) problem of making electrical release of methane from this was lower than at present, epitopes coupled to B cell contact to the fabricated warehouse has been suggested not enough methane would or CTL target epitopes. These structure. The problem is that to have caused abrupt climate have been stored to account were linked via a lipid moiety, ET AL., EMBO J once the sample is removed change (warming) in the past, for the carbon isotope shift which served to activate DCs from the ultrahigh vacuum and there are concerns that a and the abrupt warming at through binding and activation where the STM atomic warmer future climate may the Paleocene-Eocene of the innate signaling receptor manipulation has taken place, destabilize this reservoir, boundary, about 55 million TLR2. With different epitope the actual location of the which would enhance years ago. — BH CREDITS: PRAEFCKE (TOP) structure is lost, particularly warming further. Earth Planet. Sci. Lett. 227, 185 (2004). CONTINUED ON PAGE 1105 www.sciencemag.org SCIENCE VOL 306 12 NOVEMBER 2004 1103 Published by AAAS CONTINUED FROM 1103 EDITORS’ CHOICE combinations, strong antibody and CTL conjunction with solid particles, are used responses could be elicited in models of as stabilizers because they reduce the viral and bacterial infection, as well as to surface tension of the liquid, preventing tumors, and were comparable to responses the bubbles from coalescing.

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