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Nature press release for 29 August issue

August 29, 2002

[1] LIFELINES: HAIR PROTEIN SHAPES HEARING (DOI: 10.1038/nature01059) (http://dx.doi.org/10.1038/nature01059)

***This paper will be published electronically on Nature`s website on 28 August at 1900 London time / 1400 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 29 August, but at a later date.***

Hearing sensitivity in mammals is enhanced by more than 100-fold by mechanical amplification thought to be generated by the outer hair cells of the cochlea. A cell membrane protein called prestin is crucial to this process, show Jian Zuo of St Jude Children's Research Hospital, Memphis, Tennessee, and colleagues in a Nature paper published online this week. Prestin is the molecular motor that enables transmembrane voltage to change cellular length at audio frequencies.
Zuo and colleagues show that without prestin, mouse outer hair cells lose electromotility in vitro and mice suffer a 40-60-decibel loss of cochlear sensitivity. "These results suggest that there is no need to invoke additional active processes to explain cochlear sensitivity in the mammalian ear," the researchers conclude.
CONTACT:
M. Charles Liberman (co-author) tel +1 617 573 4233, e-mail liberman@attbi.com

[2] CHEMISTRY: SUGAR SWEETENS HYDROGEN REVOLUTION (pp964-967; N&V)

A new process extracts hydrogen, a non-polluting fuel, from glucose solution, report James Dumesic and co-workers at the University of Wisconsin at Madison in this week`s Nature. They have developed a platinum-based catalyst, rather like that in cars` catalytic converters, that at 200 degrees Celsius breaks down the glucose into hydrogen gas, carbon dioxide and methane.
The glucose comes from plant and animal matter. At present, this biomass is broken down by bacteria. But bacterial fermentation can be complex, inefficient and expensive on an industrial scale. Glucose is manufactured in vast quantities - for example, in the form of corn syrup - from corn starch, but Dumesic`s team hopes that a more efficient, less expensive version of their process might one day work with waste plant matter such as wood pulp, straw, and the fibrous leftovers from corn production.
Hydrogen combustion releases a lot of energy and the only waste product is water. Many motor companies, including DaimlerChrysler and Ford, have produced prototype hydrogen-powered electric vehicles.
In an accompanying News and Views article, Esteban Chornet of the University of Sherbrooke, Québec, and Stefan Czernik of the National Renewable Energy Laboratory, Colorado, discuss the background and implications of this work.
CONTACT:
J. A. Dumesic tel +1 608 262 1095, e-mail dumesic@engr.wisc.edu
Esteban Chornet (currently at NREL) tel +1 303 384 6240, e-mail esteban_chornet@nrel.gov
Stefan Czernik tel +1 303 384 7703, e-mail stefan_czernik@nrel.gov

[3] BRAIN: PROTEIN HELPS US FORGET (pp970-975; N&V)

Memory loss with ageing may be due to the active intervention of a protein called protein phosphatase1 (PP1), rather than an irreversible rundown of molecular components.
David Genoux of the Swiss Federal Institute of Technology, ETH Hönggerberg, Zürich, and colleagues have found that mice in which PP1 activity is inhibited fare better in tests of learning and memory, and are also less prone to forget what they have learned, they report in this week's Nature. PP1 is part of the complex system that clears the brain of unwanted memory and allows re-learning.
       Results like this illustrate that "we are well on our way to unravelling the biology of memory, and of course, forgetting," say Alcino J. Silva and Sheena A. Josselyn of the University of California at Los Angeles, in an accompanying News and Views article.
CONTACT:
David Genoux tel +41 1 633 3115, e-mail david.genoux@cell.biol.ethz.ch
Alcino J. Silva tel +1 310 794 6345, e-mail Silvaa@mednet.ucla.edu

[4] ECOLOGY: WINTER STARVES SPARROWS (pp931-932)

British sparrows are disappearing because they cannot get enough food to survive the winter, researchers report in this week's Nature. The finding could help to guide conservation policy and management for farmland birds.
Rural sparrow decline seems to be an all-or-nothing affair. Some populations are doing fine, but between 10 and 20% of English farms have lost all their sparrows in the past 20 years, David Hole, of the University of Oxford, UK, and his colleagues found.
The birds' winter hardship, say the researchers, is due to a switch from spring-planted to autumn-planted crops - depriving birds of the stubble that acts like a giant bird table - and to better grain storage, which keeps seed away from birds. Sparrows are producing as many young as they ever were.
Providing extra food in winter halted the decline in sparrows at one farm, where the population has declined by 80% in the past 30 years, but had no effect on sparrows at three other farms.
CONTACT:
David G. Hole tel +44 1865 271 202, e-mail David.hole@linacre.ox.ac.uk
Grahame Madge (Royal Society for the Protection of Birds press officer) tel +44 1767 681577 (out of office hours, please tel +44 7702 196902), e-mail Grahame.Madge@rspb.org.uk

[5] PHYSICS: PRACTICAL LASER FUSION (pp933-934)

Using a petawatt (1015 watts) laser, researchers have demonstrated the potential feasibility of a novel form of nuclear fusion, according to a Brief Communication in this week`s Nature.
One alternative to conventional power generation is harnessing nuclear fusion - the same reaction that powers our Sun and atomic explosions. Doing this is problematic, however, as the nuclei of atoms must be heated to temperatures of around 50 million degrees Celsius before they fuse and release vast amounts of energy.
One approach to creating an artificial Sun involves magnetic-filed trapping of a swimming-pool-sized mass of highly energized tritium (a form of heavy hydrogen three times the normal mass) fuel in the form of a plasma, and heating it to the temperature required for fusion.
The idea for another, and potentially far cheaper, approach has been around for a while. It uses a high-powered laser to fuse a small amount of super-dense fuel, in this case deuterium. Previously, R. Kodama and the Fast-Ignitor Consortium at Osaka University in Japan and colleagues (Nature 412, 798-802; 2001) demonstrated the potential of the technique, but did not show that it could work on a large scale.
Now, using one of the most powerful lasers available, the team have shown that, in principle, it is possible to heat fusion fuel to the temperatures necessary for power generation on an industrial scale.
CONTACT:
R. Kodama tel +81 6 6879 8754, e-mail ryo@ile.osaka-u.ac.jp

[6] LIFELINES: DEFENCE CAUGHT ON CAMERA (pp983-988 and 988-994; N&V)

When microbes attack vertebrates, dendritic cells help to raise the alarm in the immune system. Two papers in this week`s Nature present an unprecedented inside view of how these cells go about their business, taken using real-time microscopy.
Upon meeting a pathogen, dendritic cells mature and migrate to the nearest lymph node, carrying bits and pieces of the invaders. Inside dendritic cells, the foreign proteins, called antigens, are diced into short pieces and loaded on to cell proteins, MHC class I or class II molecules, that take the fragments back to the cell surface and present them to T cells. T cells that recognize these fragments of pathogen then secrete a range of molecules that summon and organize more immune cells, and harm the microbe.
Both groups have captured the alterations in the transport of MHC class II molecules that occur after maturation of dendritic cells through fusing green fluorescent protein (GFP) to the tail of class II molecules.
Hidde L. Ploegh of Harvard Medical School, Boston, and colleagues genetically engineered mice so that all of their MHC class II molecules glowed with green fluoresecent protein. They then took a dramatic three-dimensional picture of the distribution of dendritic cells in living skin. Next they visualized the intracellular movement of the GFP-tagged class II molecules by time-lapse imaging cultured dendritic cells. Most remarkable is their demonstration that within minutes of meeting T cells that recognize a presented antigen, extraordinarily long tubules shuttle class II molecules right to the interface between the dendritic cell and the T cell. When a dendritic cell interacts with several T cells at the same time, many tubules form simultaneously to deliver class II molecules to each T cell.
Ira Mellman of the Yale University School of Medicine, New Haven, Connecticut, and colleagues worked with GFP-tagged class II molecules in cultured dendritic cells. They show that, within 30 minutes of adding bacterial material, tubules emanate from the middle of the cell to its membrane. Class II molecules are shuttled along these tubules to the cell surface. Although this route is known only in dendritic cells, it is likely to exist in other cells.
"The finding that only T cells that recognize their antigen induced tubule polarization raises a conundrum: if there is already enough MHC-antigen on the surface of the dendritic cell to allow recognition by the T cell, why transport more of it to the synapse?" ask Jonathan W. Yewdell and David C. Tscharke of the National Institute of Allergy and Infectious Diseases, Bethesda in an accompanying News & Views article.Visualizing the inner lives of immune cells at work in living animals, in this way, "is bound to revolutionize our understanding of the immune system," they conclude
CONTACT:
Hidde L. Ploegh tel +1 617 432 4777, e-mail ploegh@hms.harvard.edu
Ira Mellman tel +1 203 785 4303/02, e-mail Ira.mellman@yale.edu
Jonathan W. Yewdell tel +1 301 402 4602, e-mail jyewdell@nih.gov

[7] SPACE: EARTH FORMED DOUBLE QUICK (pp949-952 and 952-955; N&V)

We know that the Earth formed about the same time as our Sun, but precisely when it reached something like its present size has been very controversial. The technique seemingly best suited to answering the question - determining the ratios of radioactive hafnium and tungsten - gave an answer that was about 30 million years longer than any other indicator or theoretical model.
In two papers in this week's Nature, Qingzhu Yin, at Harvard University and colleagues, and separately Thorsten Kleine, at the University of Muenster in Germany, re-analysed the ratios of the radioactive elements hafnium and tungsten in meteorites (which represent rocks around the same age as the Solar System) and compared them to rocks from Earth and Mars. Both groups find that previous estimates of how quickly the Earth formed - about 60 million years after the birth of the Solar System - are wrong.
Their calculations suggest that the Earth formed in the first 30 million years and Mars, because it is smaller, in about 13 million years. Although the finding doesn`t answer any questions about how and why solar systems form, it does resolve some confusion about our own Solar System. Planetary scientists were worried because previous measurements of radioactive elements disagreed with computer models of solar system formation. The new data agree with models quite well.
In an accompanying News and Views article, A. G. W. Cameron of the University of Arizona, Tucson, considers the implications of the two papers for current theories about the formation of the inner planets and our Moon.
CONTACT:
Qingzhu Yin contactable via email only, e-mail yin@fas.harvard.edu
(currently seeking additional contacts - will be uploaded to press site if available)
T. Kleine tel +49 251 833 3489, e-mail tkleine@nwz.uni-muenster.de
A. G. W. Cameron tel +1 520 621 6362, e-mail acameron@lpl.arizona.edu

[8] LIFELINES: CLOCK WATCH (pp935-941)

Such remarkable progress has been made in unravelling the molecular basis of the mammalian circadian clock that treatments are being developed for jet lag and some sleep ailments.
In a Review Article in this week's Nature, Steven M. Reppert and David R. Weaver of the University of Massachusetts Medical School, Worcester, Massachusetts, describe current knowledge of the transcriptional and post-transcriptional mechanisms that make up the circuitry of the mammalian 24-hour clock - including the brain`s master clock that coordinates tissue-specific clocks scattered around the body.
CONTACT:
Steven M. Reppert tel +1 508 856 6148, e-mail steven.reppert@umassmed.edu

[9] PHYSICS: IMAGE ENHANCEMENT (pp959-964)

Optical coherence tomography, or OCT, is a medical imaging technology that uses infrared light to visualize subsurface structure in biological tissues - rather like ultrasound but with infrared echoes and an added element of microscopy. An advance, reported in this week`s Nature, in materials for near-infrared holographic recording could lead to significant improvements in OCT imaging, by improving the recording speed possible for reversible holographic image storage media.
Klaus Meerholz of the University of Munich, and colleagues describe a new organic photorefractive polymer with good near-infrared recording characteristics that is improved 40-fold in its response time by a pre-illumination process. OCT is already finding favour with ophthalmologists as a way of examining the eye in cross-section, and may have application in cardiology and cancer diagnosis. Faster recording media would improve OCT performance over large target areas, and would reduce the motion artefacts sometimes encountered in OCT scans.
CONTACT:
Klaus Meerholz (currently at the Univ of Cologne) tel +49 221 470 3275,
e-mail Klaus.meerholz@uni-koeln.de

[10] AND FINALLY: GENETICS OF NORMAL COGNITIVE DECLINE (p932)

An experiment examining the normal changes in mental ability that people may undergo as they get older suggests that those carrying a copy of a particular gene seem to undergo a greater change.
In a Brief Communication to this week`s Nature, Ian Deary at the University of Edinburgh and colleagues report that a certain type of the gene encoding apolipoprotein E (APOE e4), which, among other things, is involved in repairing nerve cells, seems to be associated with greater cognitive change in the elderly who have no obvious clinical signs of dementia or of Alzheimer`s disease.
Deary`s team studied a large group of people who, at age 11, took part in the Scottish Mental Survey of 1932. Deary`s team contacted 491 of the surviving 80-year-old participants of the survey living in and around Edinburgh. After discounting those reporting clinical forms of dementia, they asked the remainder to repeat the IQ-type test they took as children.
The 80-year-olds` scores were largely determined by how well they did when they were 11. People with and without the APOE e4 gene had similar test scores at age 11. But at age 80 those with the gene fared significantly worse compared to those without APOE e4.
APOE e4 is also associated with a susceptibility to Alzheimer`s disease, and although none of the group showed any symptoms of this, the link could be due to very early, as yet undetected Alzheimer`s. But the number of people with changes in mental ability who also had the APOE e4 gene was far higher than the natural incidence of Alzheimer`s, making this association less likely, the researchers say.
CONTACT:
John Starr tel +44 131 537 5000 (ask to bleep Dr. Starr), e-mail john.starr@ed.ac.uk
Martha Whiteman tel +44 131 650 3317, e-mail m.whiteman@ed.ac.uk

ALSO IN THIS ISSUE

[11]                Open channel structure of MscL and the gating mechanism of mechanosensitive channels (pp942-948)

[12]         Metal-insulator transition in chains with correlated disorder (pp955-959)

[13]       Chromosomal clustering of muscle-expressed genes in Caenorhabditis elegans (pp975-979)

[14]       A chromatin remodeling complex that loads cohesin onto human chromosomes (pp994-998)

[15]       Reverse engineering of the giant muscle protein titin (pp998-1002)

[16]       RAFI RAS oncogenes and mismatch-repair status (p934)

GEOGRAPHICAL LISTING OF AUTHORS

The following list of places refers to the whereabouts of authors on the papers numbered in this release. The listing may be for an author`s main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.

AUSTRALIA
       Crawley: 11

CZECH REPUBLIC
       Prague: 6

FRANCE
       Lyon: 7

GERMANY
       Cologne: 7, 9
       Heidelberg: 15
       Jena: 9
       Muenster: 7
       Munich: 9

ITALY
       Turin: 16

JAPAN
       Kobe: 7
       Osaka: 5

THE NETHERLANDS
       Groningen: 9

SPAIN
       Malaga: 12

SWITZERLAND
       Zurich: 3

THAILAND
       Bangkok: 11

UNITED KINGDOM
       Aberdeen: 10
       Belfast: 5
       Didcot: 5
Edinburgh: 4, 10
       Essex: 5
       London: 5
       Oxford: 4
       Sandy: 4
       Swansea: 4

UNITED STATES OF AMERICA
California
       Irvine: 14
       Stanford: 13
Connecticut
       New Haven: 6
Maryland
       Baltimore: 16
Massachusetts
       Boston: 1, 6, 12
       Cambridge: 6, 7
       Worcester: 8
Minnesota
       Rochester: 15
Missouri
       St. Louis: 15
Nebraska
       Omaha: 1
Pennsylvania
       Philadelphia: 14
Tennessee
       Memphis: 1
Washington State
       Seattle: 3
Wisconsin
       Madison: 2
Virginia
       Charlottesville: 11

Nature Publishing Group Reference