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This press release is copyright Nature. VOL.442 NO.7106 DATED 31 AUGUST 2006
This press release contains:
* Summaries of newsworthy papers:
Reproductive biology: Worm sperm provides clue to male infertility
News: Cheap IVF could help tackle Africa's infertility problem
Astrophysics: Big bursts from smaller stars
Spectroscopy: Making light of magnetic resonance
And finally… Plankton carbon storage was overestimated
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors
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[1] Reproductive biology: Worm sperm provides clue to male infertility (AOP)
DOI: 10.1038/nature05050
***This paper will be published electronically on Nature's website on 30 August at 1800 London time / 1300 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 31 August, but at a later date.***
In a study that could fuel treatments for infertility, Barbara Meyer and colleagues have used a model organism, the nematode worm Caenorhabditis elegans, to identify a raft of new proteins vital for healthy sperm production. Their findings are published online this week by Nature.
The quality of sperm chromatin (DNA packaged with associated proteins) is known to be an important indicator of male fertility, and Meyer's team set out to identify proteins important for sperm chromatin structure. They purified those proteins uniquely and richly associated with sperm chromatin in C. elegans, and tested their function using RNA interference of all 132 proteins identified. The team,found that some were vital for DNA packaging, chromosome segregation and fertility.
In some cases, it is already known that disabling the equivalent proteins in mice causes male sterility. This list of proteins may help identify causes of and diagnostic tests for unexplained male infertility in humans or provide targets for male contraceptives.
CONTACT
Barbara Meyer (Howard Hughes Medical Institute & University of California, Berkeley, CA, USA)
Tel: +1 510 643 5585; E-mail: [email protected]
News: Cheap IVF could help tackle Africa's infertility problem (pp 975-977)
Fertility treatment isn't something most westerners associate with sub-Saharan Africa. But infertility is in fact a huge problem on that subcontinent, affecting up to a third of couples. According to a News Feature in Nature this week, scientists are trying to develop cheap alternatives to conventional IVF to combat it.
Conventional treatments cost thousands of dollars and are beyond the reach of most Africans. The new low-cost methods include cheap alternatives to the drugs used to make a woman ovulate and basic lab equipment that costs just a tenth of the high-tech western equivalent. But these need to be clinically tested, and a lack of awareness, money and political will means this has yet to happen.
One big problem is prejudice. Governments worldwide believe Africa has an over-fertility problem, and plough money into family planning schemes rather than infertility treatments. Within sub-Saharan Africa, the stigma surrounding infertility is immense, and women are usually blamed. Many are thrown out of their homes, ostracised by relatives, or encouraged to sleep with their brothers in law to cover up their husbands' infertility. Few receive proper medical treatment.
Much of this infertility is caused by sexually transmitted diseases and could be reduced by promoting condom use and proper treatment of infections. But this relies on improving the status of women and access to medical facilities.
CONTACT
Helen Pilcher (Journalist, UK)
E-mail: [email protected]
[2], [3], [4] & [5] Astrophysics: Big bursts from smaller stars (pp1008-1020; N&V)
The intense cosmic outbursts of high-energy radiation known as gamma-ray bursts (GRBs) - among the most energetic astrophysical processes known - are thought to arise from the collapse of massive stars in a supernova. But not all supernovae generate GRBs, and it remains unclear what causes some but not others to produce these bursts. Four international teams of astronomers report in Nature this week different views of a burst event that occurred in February 2006, which promises to yield new insights into the process.
This burst, GRB060218, which occurred 440 million light years away in the constellation of Aries, was a mild type of GRB known as an X-ray flash. These are not as bright as normal GRBs, and don’t produce as many gamma rays. It was previously unclear whether X-ray flashes were generated by the same basic process of stellar collapse during a supernova. But the new results seem to make that link secure. A team led by Elena Pian, and another headed by Sergio Campana, show that GRB060218 was associated with a supernova called SN2006aj. The researchers think that this supernova was less energetic than those that produce fully fledged GRBs, but brighter than supernovae that don’t generate such bursts at all.
Alicia Soderberg and her colleagues have used observations of GRB060218 at radio and X-ray wavelengths to deduce that it was around a hundred times less energetic than ordinary GRBs - but they think such events should be ten times more common. The burst was unusual in that it went on producing X-rays for several weeks, which the researchers say was the result of high-energy debris thrown out by the explosion.
But what kind of collapsing star created the event? Campana and colleagues calculate that it was probably smaller than the stars of normal GRB-producing supernovae. And Paolo Mazzali and his colleagues use the observations of Pian’s team to deduce that the progenitor star had a mass only about 20 times that of our Sun. Whereas it has been suggested that stars that generate full GRBs as they collapse end up as black holes, the progenitor of SN2006aj and GRB060128 is thus too small to have done so, and instead probably collapsed to form a neutron star. So black-hole formation does not seem to be an essential component of GRBs.
CONTACT
Elena Pian (INAF Astronomical Observatory of Trieste, Italy) Author paper [2]
Tel: +39 040 319 9219; E-mail: [email protected]
Sergio Campana (INAF Osservatorio Astronomico di Brera, Merate, Italy) Author paper [3]
Tel: +39 999 1177; E-mail: [email protected]
Alicia Soderberg (California Institute of Technology, Pasadena, CA, USA) Author paper [4]
Tel: +1 626 395 4095; E-mail: [email protected]
Paolo Mazzali (Max-Planck Institute, Garching, Germany) Author paper [5]
Tel: +49 89 300 002 221; E-mail: [email protected]
Contact for press in Japan for paper [5]:
Ken'ichi Nomoto (University of Tokyo)
Tel: +81 03 5841 4255; E-mail: [email protected]
Timothy R Young (University of North Dakota, ND, USA) N&V author
Tel: +1 701 777 4709; E-mail: [email protected]
[6] Spectroscopy: Making light of magnetic resonance (pp1021-1024; N&V)
A new way of conducting nuclear magnetic resonance (NMR) that could have a significant impact on fundamental scientific research and practical applications is reported in Nature this week.
NMR is an important tool for analysing the structures of molecules, and is also the basis of the medical technique of magnetic resonance imaging (MRI). It takes advantage of the fact that some atomic nuclei are magnetic. Placed in a strong magnetic field, such nuclei will absorb electromagnetic radiation at certain radio frequencies. This provides information about the molecular-scale environment in which the nuclei sit, while the way that the NMR signal changes over time reveals aspects of their dynamical behaviour, such as their tumbling in fluid flow.
But if we want to know about the positions of the atoms in space - to make a compositional map, or to determine the structure of a molecule - it is generally necessary to modify the experiments in complex ways. Mike Romalis and colleagues developed a new way of capturing the information, by looking at the way the nuclear magnetic fields affect polarized light. Thanks to the Faraday effect, the plane of polarized light can be rotated by a magnetic field. The researchers have now shown that this effect can be used to measure an NMR signal by shining a polarized laser beam through a liquid sample and observing how much the polarization is rotated as it passes through. This technique, which the team has demonstrated for liquid xenon and for water, allows the NMR measurement to be made at a spatial scale limited only by the size of the spot into which the laser can be focused.
CONTACT
Michael Romalis (Princeton University, NJ, USA)
Tel: +1 609 258 5586; E-mail: [email protected]
Warren S Warren (Duke University, Durham, NC, USA)
Tel: +1 919 660 1604; E-mail: [email protected]
[7] And finally…Plankton carbon storage was overestimated (pp1025-1028)
The amount of carbon taken up by plant plankton in the tropical Pacific Ocean each year may be as much as 2.5 billion tonnes less than previous estimates, say oceanographers who have completed the most comprehensive survey of nutrient dynamics in this region. The difference exceeds the [severe] decrease in tropical Pacific productivity that accompanied the largest El Niño to La Niña transition on record
Michael Behrenfeld and his colleagues spent 12 years gathering data from some 58,000 kilometres of ship transects to evaluate the growth of plankton in the region. They used the characteristics of the fluorescence produced by plankton to determine the various factors that limit plankton growth in different areas.
The results indicate that plankton growth is limited by the amount of iron in the water in equatorial and more southerly regions. Further north, growth is limited by nitrogen levels and grazing by tiny animals. They also show that satellite estimates of productivity may over-estimate the amount of carbon sequestered by plankton in this area, which releases more carbon into the atmosphere than any other ocean region in the world.
CONTACT
Michael Behrenfeld (Oregon State University, Corvallis, OR, USA)
Tel: +1 541 737 5280; E-mail: [email protected]
ALSO IN THIS ISSUE…
[8] Discovery of a magma chamber and faults beneath a Mid-Atlantic Ridge hydrothermal field (pp 1029-1032)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 30 August at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 31 August, but at a later date.***
[9] Structure of a bacterial multidrug ABC transporter
DOI: 10.1038/nature05155
[10] Crystal structure of an H/ACA box ribonucleoprotein particle
DOI: 10.1038/nature05151
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. 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
Western Creek: 4
CANADA
Victoria: 2
CHILE
Santiago: 2
CHINA
Beijing: 2, 5, 10
Nanjing: 2, 3
DENMARK
Copenhagen: 2
FRANCE
Paris: 8
GERMANY
Garching: 2, 5
Tautenbug: 2
ISRAEL
Jerusalem: 4
Rehovot: 3
ITALY
Bologna: 2
Ferrara: 2
Florence: 3
Merate: 3
Milan: 3
Padua: 2
Palermo: 3
Rome: 3
Trieste: 2, 3, 5
JAPAN
Hiroshima: 2
Tokyo: 2, 5
PORTUGAL
Lisbon: 8
SPAIN
Granada: 2
SWEDEN
Stockholm: 2
SWITZERLAND
Zurich: 9
THE NETHERLANDS
Amsterdam: 2
UNITED KINGDOM
Cambridge: 4
Hatfield: 2
Leicester: 2, 3
Surrey: 3
Swindon: 3
UNITED STATES OF AMERICA
Alabama
Huntsville: 2
California
Berkeley: 1, 2, 5
Claremont: 4
La Jolla: 1
Moss Landing: 7
Pasadena: 4
Rohnert Park: 3
San Francisco: 1
Santa Barbara: 2, 3, 5
Santa Cruz: 2
Delaware
Wilmington: 1
District of Columbia
Washington: 3
Hawaii
Honolulu: 4
Maryland
Baltimore: 2
Columbia: 3
Greenbelt: 3, 4, 7
Massachusetts
Woods Hole: 8
Nevada
Las Vegas: 3
New Jersey
Brunswick: 7
Princeton: 2, 6
New Mexico
Los Alamos: 3
Socorro: 4
Oregon
Corvallis: 7
Pennsylvania
University Park: 3, 4
Virginia
Charlottesville: 4
Washington
Seattle: 7
PRESS CONTACTS…
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Helen Jamison, Nature London
Tel: +44 20 7843 4658; E-mail [email protected]
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