Story ideas from the Proceedings of the National Academy of Sciences

PNAS Tipsheet for October 26-30

ARTICLE HIGHLIGHTS

• Climate change can begin at home
• Chemical may attract West Nile Virus-harboring mosquitoes
• Lack of contact, lack of cancer
• Genes altering nicotine response found in fish and humans

ALSO OF INTEREST

• Moving a phantom limb
• Mapping the use of metals
• The indirect cost of viral resistance in transgenic squash

Climate change can begin at home

Researchers suggest that household action may be able to reduce carbon emissions while longer-term options are developed, and a study has identified a set of actions that people can implement in their daily lives to make significant reductions. Thomas Dietz and colleagues analyzed five broad categories of actions that people can take immediately: home weatherization through insulation and heating and cooling equipment, using more efficient vehicles and equipment, performing equipment maintenance to ensure proper running order, making equipment adjustments for optimal performance, and modifying daily behaviors. The specific actions in these categories ranged from one-time tasks such as installing better insulation and lowering the temperature on water heaters, to ongoing tasks like changing driving behavior. The group found that 17 actions could reduce annual household carbon emissions in the United States by up to 20 percent, which could reduce total national emissions by nearly 7.4 percent in 10 years. Notifying the public of such individual actions and potential benefits could allow federal regulators and policy-makers to effect a "behavioral wedge" capable of effecting short-term greenhouse gas reductions in the future, according to the researchers.

Article #09-08738: "Household actions can provide a behavioral wedge to rapidly reduce U.S. carbon emissions," by Thomas Dietz, Gerald T. Gardner, Jonathan Gilligan, Paul C. Stern, and Michael P. Vandenbergh

MEDIA CONTACT: Thomas Dietz, Department of Environmental Science and Policy, Michigan State University, East Lansing, MI; tel: 517-333-3452 (day), 802-238-2601 (evening); e-mail: tdietz@msu.edu

Chemical may attract West Nile Virus-harboring mosquitoes

Researchers have found that a naturally produced chemical may attract mosquitoes of the genus Culex, which is associated with West Nile Virus transmission. Zainulabeuddin Syed and Walter Leal identified the odorant nonanal in a screen of chemicals from multiple human ethnic groups and from multiple bird species. Of the hundreds of chemicals the authors tested, only nonanal elicited strong responses in olfactory receptor neurons housed in the antennae of Culex quinquefasciatus, the southern house mosquito. The researchers report that mosquito traps baited with nonanal lured large numbers of the insects, and suggest that the nine-carbon molecule acts synergistically with carbon dioxide, a known mosquito attractant. West Nile Virus, which has emerged as the dominant vector-borne disease in North America, is a significant public health threat, as pathogen-carrying mosquitoes infect thousands of people, birds, and animals annually. The researchers suggest that their finding may help in the development of mosquito attractants to reduce mosquito-borne diseases such as West Nile Virus and malaria.

Article #09-06932: "Acute olfactory response of Culex mosquitoes to a human- and bird-derived attractant," by Zainulabeuddin Syed and Walter S. Leal

MEDIA CONTACT: Walter Leal, Department of Entomology, University of California-Davis, Davis, CA; tel: 530-752-7755 (day), 530-750-2320 (evening); e-mail: wsleal@ucdavis.edu

Lack of contact, lack of cancer

Researchers have identified a potential mechanism by which naked mole rats can survive up to 28 years without developing cancerous tumors. Vera Gorbunova and colleagues report that the unusual cancer resistance in the rodents may originate in cells hesitant to crowd their neighbors. Normally, mammalian cells stop replicating when they come into dense contact with one another, but cancer cells ignore this signal and continue to proliferate, which allows them to clump into tumors in the body. The researchers measured the growth of mole rat cells and found that cellular growth in the animals was hypersensitive to first contact, compared to mouse cells that continued growing into a dense layer. Naked mole-rat cells forced into high-density situations arrested their growth or even died. The authors investigated the pathways responsible for this early contact inhibition and report that two fibroblast pathways are likely responsible for the key anticancer mechanism. Their research shows that inactivating these tumor-suppressor pathways can allow the mole rats to develop cancer. The ability of naked mole rat cells to eschew dense contact could explain the animal's longevity, the researchers suggest.

Article #09-05252: "Naked mole-rat cells are hypersensitive to contact inhibition-a clue to extraordinary cancer resistance," by Andrei Seluanov, Christopher Hine, Jorge Azpurua, Marina Feigenson, Michael Bozzella, Zhiyong Mao, Kenneth C. Catania, and Vera Gorbunova

MEDIA CONTACT: Vera Gorbunova, Department of Biology, University of Rochester, Rochester, NY; tel: 585-275-7740 (day), 585-472-1234 (evening); e-mail: vgorbuno@mail.rochester.edu

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Genes altering nicotine response found in fish and humans

Researchers have developed a system to search for genetic variations that may be responsible for altering an organism's physiological and behavioral responses to nicotine. Studies have shown that an individual's response to nicotine, the addictive ingredient in tobacco, is heavily dependent on their genetic makeup. Stephen Ekker and colleagues used a model organism called the zebrafish and introduced genetic variations in the animals known to alter predisposition to addiction and lung cancer vulnerability. The researchers added varying levels of nicotine to the water and monitored the movements of each transgenic animal to test the fishes' nicotine response. When the fish were exposed to high nicotine levels, their movement slowed. At intermediate doses, the fish swam more quickly. The genetic screening system also detected two previously unidentified genetic variations--also present in humans--that impacted nicotine response in zebrafish. The research may provide proof that zebrafish are a suitable model for studying addiction and could be used to identify genetic markers that predispose people to various addictions, the authors say.

Article #09-08247: "Nicotine response genetics in the zebrafish," by Andrew M. Petzold, Darius Balciunas, Sridhar Sivasubbu, Karl J. Clark, Victoria M. Bedell, Stephanie E. Westcot, Shelly R. Myers, Gary L. Moulder, Mark J. Thomas, and Stephen C. Ekker

MEDIA CONTACT: Stephen Ekker, Department of Biochemistry and Molecular Biology, Mayo Clinic Cancer Center, Rochester, MN; tel: 507-284-5530 (day), 507-250-5215 (evening); e-mail: ekker.stephen@mayo.edu

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ALSO OF INTEREST

Moving a phantom limb

Amputees with a vivid sense of their missing "phantom" limb could visualize actions that were not limited by normal anatomical constraints.

Article #09-07151: "The interdependence of movement and anatomy persists when amputees learn a physiologically impossible movement of their phantom limb," by G. Lorimer Moseley and P. Brugger

MEDIA CONTACT: Lorimer Moseley, Prince of Wales Medical Research Institute and University of New South Wales, Randwick, NSW, AUSTRALIA; tel: +61-2-939-91-266; e-mail: lorimer.moseley@gmail.com

Mapping the use of metals

A map of the primary industrial metals used by humans has revealed how and where people have extracted, moved, and concentrated the metals from the Earth.

Article #09-00658: "Global mapping of Al, Cu, Fe, and Zn in-use stocks and in-ground resources," by Jason N. Rauch

MEDIA CONTACT: Jason Rauch, Yale School of Forestry and Environmental Studies, Yale University, New Haven, CT; tel: 203-432-4985; email: jason.rauch@yale.edu

The indirect cost of viral resistance in transgenic squash

Viral resistant transgenic cucurbita (the species that includes pumpkins and gourds) are typically larger and healthier than wild squash but are a preferred target for insect herbivory.

Article #09-05106: "Indirect costs of a non-target pathogen mitigate the direct benefits of a virus resistant transgene in wild cucurbita," by Miruna A. Sasu, Matthew J. Ferrari, Daolin Du, James A. Winsor, and Andrew G. Stephenson

MEDIA CONTACT: Andrew Stephenson, Department of Biology, Pennsylvania State University, University Park, PA; tel: 814-863-1553; e-mail: as4@psu.edu