Nature Press Release for 18th April IssueApril 18, 2002[416740] LIFELINES: LUNG BACTERIA MORPH INTO LETHAL FORM (pp740-743; N&V) Swathes of antibiotic-resistant bacteria known as biofilms frequently infect the lungs of patients suffering cystic fibrosis (CF), and are often fatal. In this week's Nature, Eliana Drenkard and Frederick Ausubel of Harvard Medical School in Boston suggest how the normally innocuous bacteria, Pseudomonas aeruginosa, change into a more dangerous state. They show that natural variations in the bacteria enable some of them to `phase-shift` into a form that can grow in the presence of antibiotics and which is adept at forming biofilms. The two properties appear to be switched on together. Conditions present in the lungs of CF patients means that there is a small population of bacteria in this naturally antibiotic-resistant form, suggests Ausubel. These survive drug treatment and proliferate into biofilms, which are themselves antibiotic-resistant. Importantly, the researchers identified a protein that regulates the phase-shift. A drug that targets this protein might shift the bacteria back into their antibiotic-susceptible state, says George O'Toole of Dartmouth Medical School in New Hampshire, in an accompanying News and Views article. CONTACT: Frederick M. Ausubel tel + 1 617 726 5969, e-mail ausubel@molbio.mgh.harvard.edu George O'Toole tel +1 603 650 1248, e-mail george.a.o'toole.jr@dartmouth.edu [416716] CHEMISTRY: SHINY NEW METAL OBJECT (pp716-719) An improved technique for coating objects with metal is described in this week`s Nature. Mirrored clothes and plastics could in theory be made this way. Electroplating uses an electric current to carry positively charged metal ions to a negatively charged object, where they gain electrons and are deposited as metal. But this application has previously been limited to substrates that conduct electricity. Vincent Fleury of the Ecole Polytechnique/CNRS in Palaise au Cedex, France, and colleagues have devised a way to coat non-conducting substrates. They positioned a plate next to the negatively charged cathode and devised current conditions that cause the metal film to spread from the cathode evenly over the plate. The team demonstrated its effectiveness with copper and tin on glass and Teflon. The process could be used to coat metal onto fibres, ribbons and plates, the authors suggest, and to mirror unusual surfaces. CONTACT: Vincent Fleury tel +33 1 69 33 42 87, e-mail vincent.fleury@polytechnique.fr [416729] ECOLOGY: FISH STOCKS NATURALLY SINK AND SWIM (pp729-733) Fish stocks can crash without human help, researchers have found. A 2,200-year record of Pacific salmon populations reveals that fish numbers went into decline between 100 BC and 800 AD, rose around 1200 and stayed high until about 1900, when climatic and human impacts began to reduce the population. The nutrients in salmons` bodies are released into their home lakes and rivers after they have spawned and died. The size of this fertilizing effect gives a measure of the salmon population of the time. Drilling into the sediment of lakebeds on Kodiak Island, Alaska, allowed Bruce Finney of the University of Alaska Fairbanks, and Irene Gregory-Eaves of Queen's University, Kingston, Ontario, Canada and colleagues to read this record. The changes in salmon numbers correspond to the dates of major climatic changes in the Pacific. The finding, reported in this week's Nature, shows the importance of incorporating an understanding of climate change into our attempts to manage fisheries. CONTACT: Bruce P. Finney tel +1 907 474 7724, e-mail finney@ims.alaska.edu Irene Gregory-Eaves +1 613 533 6147, e-mail gregoryr@biology.queensu.ca [416711] SPACE: ROCKS TWIRL IN REMOTE TWO-STEP (pp711-713; N&V) The Kuiper belt is the new `hot spot` of our Solar System. This region of space extends at least 70 astronomical units beyond Neptune`s orbit (the Sun-Earth distance is one astronomical unit) and contains the source of new short-period comets as well as bodies that blur the distinction between comets and asteroids. Because of their extreme distance, it is hard to determine the important physical properties, such as density, size and colour, of the Kuiper belt objects. Only if we can get completely independent information is it possible to sort out their properties. Christian Veillet of the Canada-France-Hawaii Telescope in Hawaii, and colleagues now provide the possibility of that independent information with the discovery that the Kuiper belt object named 1998 WW31 actually has its own tiny moon, which orbits surprisingly far away. This is very different from the only other known Kuiper-belt binary, which is the Pluto-Charon system. The WW31 companions follow an elongated, ellipse-shaped orbit that keeps them 22,000 kilometres apart, they report in this week`s Nature, and complete a rotation every 570 days. Mutual eclipses of the two bodies would allow determination of their individual sizes, and therefore densities, which would provide clues as to the compositions of the bodies. CONTACT: Christian Veillet tel +1 808 885 3161 , e-mail veillet@cfht.hawaii.edu [416719] CLIMATE: FAIRER 20 YEAR CLIMATE FORECAST (pp719-723; pp723-726; N&V) Two papers in this week`s Nature attempt to incorporate uncertainties surrounding global climate change into temperature forecasts for the next 2-3 decades. Peter Stott of the Met Office in Bracknell and Jamie Kettleborough of Rutherford Appleton Laboratory in Didcot, UK, estimate that the global mean temperature in 2020-2030 will be 0.3-1.3 °C warmer than the period between 1990-2000. Stott and Kettleborough also point out that, on the timescales of several decades, the greatest uncertainty lies with the responses of the climate system to greenhouse gas emissions, whereas different emission scenarios (in the absence of mitigation policies) render very similar results. Using an alternative model, Thomas F. Stocker and his team at the University of Bern in Switzerland present a consistent picture: they suggest a probable warming of 0.5-1.1°C over the same period. They also show that the indirect aerosol effect, which causes cooling of almost unknown magnitude, is restricted to the range between 0 and -1.2 W per m2. Both groups place a 5-95% probability on their prediction of medium-term temperature changes. This makes the figures more useful to policymakers attempting to assess the expected costs and benefits of their actions, says Francis Zwiers of the University of Victoria in Canada, in an accompanying News and Views article. CONTACT: Peter Stott tel +44 1344 854 011, e-mail peter.stott@metoffice.com Thomas F. Stocker +41 31 631 44 64/62, e-mail stocker@climate.unibe.ch Francis Zwiers +1 250 363 8229, e-mail Francis.Zwiers@ec.gc.ca [416726] EVOLUTION: A DATE WITH OUR LAST COMMON ANCESTOR (pp726-729) Biologists have estimated that the last common primate ancestor lived 81.5 million years ago. Their new model, reported in this week's Nature, suggests that no more than 7% of all primate species that have ever existed have been unearthed as fossils. According to previous studies, the lineage leading to primates diverged from other placental mammals about 90 million years ago. But these estimates, based on comparisons of modern genetic sequences, are considerably before recognizable primates appear in the fossil record 54-55 million years ago. Simon Tavare of the University of Southern California, Los Angeles and his team devised a computational model to resolve the discrepancy. Their method estimates the time gap between the oldest known fossils and the last common ancestor of a group. It is based on an estimate of the proportion of species actually preserved in the fossil record and the rate with which they diversified. CONTACT: Simon Tavare tel +1 213 740 8766, e-mail stavare@usc.edu [416701] LIFELINES: FEED-THE-WORLD GENE SUSSED (pp701-702) Millions of people born since the 1960s owe their lives to a single mutant gene. But the gene called sd1 doesn`t cure cancer or prevent heart disease - it reduces the height of rice plants to make a small area more productive and so became a cornerstone of the green revolution. Forty years after a rice strain containing mutant sd1 was created, M. Ashikari and colleagues at Nagoya University in Japan identify, in a Brief Communication to this week`s Nature, how sd1 works. The gene regulates the synthesis of giberellin, a plant hormone that stimulates growth. The mutant form of sd1 limits the production of giberellin in the leaves and stems to give a semidwarf plant whose rice yield is unaffected. Green-revolution crop varieties of wheat, on the other hand, contain mutations that affect the hormone function of giberellin. The findings indicate that the giberellin system is an important target for future improvement of crop varieties, made easier by the recent sequencing of the entire rice and other plant genomes. CONTACT: M. Ashikari tel +81 52 789 5225, e-mail ashi@nuagr1.agr.nagoya-u.ac.jp [416702] CHEMISTRY: POWDER TRANSFORMED TO FOAM (pp702) By mixing vanadium oxide with hydrogen peroxide and a surfactant polymer, chemists can convert a gram of a metal oxide gel into a voluminous 3 litres of foam, they announce in a Brief Communication to this week`s Nature. Oxygen produced once the hydrogen peroxide is added generates a bright yellow frothy mass, report Jaques Livage and colleagues at the University of Paris 6, France. The bubbles of the foam act as large pores and the surfactant molecules slot into the honeycomb structure of vanadium oxide. This bizarre foam could be a boon to chemists and industrialists as vanadium oxide is an important catalyst, and in foam-form could vastly increase the surface area for catalysing chemical reactions. The authors hope to make foams of molybdenum, titanium and zirconium oxides using the same technique. CONTACT: Jaques Livage tel +33 1 44 27 33 65, e-mail Livage@ccr.jussieu.fr [416733]AND FINALLY: SINGLE MOTHERS PROVIDE MORE (pp733-736) Ecologists have confirmed what every mum and dad know: parents compete to escape childcare. Ian Hartley of the University of Lancaster, UK, and colleagues observed one- and two-parent zebrafinch nests. Single-parent chicks get more food than those raised by mother and father, they found - and the well-fed males reared by a single mother were more sexually attractive as adults. The difference is due to a reduction in care provided by females with a partner, rather than laziness by males or more demanding chicks, say the researchers in this week's Nature. Their observations support the idea that sexual conflict between parents can affect the quality of offspring. This occurs because each carer would benefit - in evolutionary terms - by withholding parental investment and using it to have additional offspring with another mate. CONTACT: Ian Hartley tel +44 1524 592 566, e-mail i.hartley@lancaster.ac.uk ALSO IN THIS ISSUE Structure of the Cul1 - Rbx1 - Skp1 - FboxSkp2SCF ubiquitin ligase complex Electrical detection of spin precession in a metallic mesoscopic spin valve Direct cortical input modulates plasticity and spiking in CA1 pyramidal neurons RANKL maintains bone homeostasis through c-Fos-dependent induction of interferon-ß Cells compete for Decapentaplegic survival factor to prevent apoptosis in Drosophila wing development SWAP-70 is a guanine-nucleotide-exchange factor that mediates signalling of membrane ruffling A proteasomal ATPase subunit recognises the polyubiquitin degradation signal Geobacter metallireducens accesses insoluble Fe(lll) oxide by chemo Nature Publishing Group Reference | |||||||||||||||||||||
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