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Author (up) Ashoori, R.C. file  url
openurl 
  Title Electrons in artificial atoms Type Journal Article
  Year 1996 Publication Nature Abbreviated Journal Nature  
  Volume 379 Issue 6564 Pages 413-419  
  Keywords  
  Abstract Progress in semiconductor technology has enabled the fabrication of structures so small that they can contain just one mobile electron. By varying controllably the number of electrons in these 'artificial atoms' and measuring the energy required to add successive electrons, one can conduct atomic physics experiments in a regime that is inaccessible to experiments on real atoms.

Subject Headings: Atoms; Electrons; Artificial;

Keywords: Electrons in artificial atoms
 
  Call Number Serial 2738  
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Author (up) Beitel, G.J.; Clark, S.G.; Horvitz, H.R. file  url
openurl 
  Title Caenorhabditis elegans ras gene let-60 acts as a switch in the pathway of vulval induction Type Journal Article
  Year 1990 Publication Nature Abbreviated Journal Nature  
  Volume 348 Issue 6301 Pages 503-509  
  Keywords  
  Abstract The let-60 gene, an essential ras gene of the nematode Caenorhabditis elegans, acts as a switch in the inductive signalling pathway that initiates vulva formation. Recessive let-60 mutations that cause a vulvaless phenotype prevent let-60 function in response to the inductive signal. These mutations are clustered and define regions necessary either for the activation or for the action of the let-60 ras protein. Dominant let-60 mutations that cause a multivulva phenotype alter codon 13 and activate let-60 in vivo, rendering it independent of the inductive signal. The let-60 gene acts within an extensively defined genetic pathway, and other genes within this pathway seem likely to encode molecules that regulate let-60 function as well as molecules that are targets of let-60 action.

Subject headings: Alleles; Animals; Base Sequence; Caenorhabditis/*genetics/growth & development; Chromosome Mapping; Codon; Embryonic Induction; Female; GTP-Binding Proteins/*physiology; Molecular Sequence Data; Mutation; Phenotype; Proto-Oncogene Proteins p21(ras)/*physiology; Signal Transduction; Vulva/embryology

Keywords: Caenorhabditis elegans ras gene let-60 acts as a switch in the pathway of vulval induction
 
  Call Number Serial 2905  
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Author (up) Bieling, P.; Laan, L.; Schek, H.; Munteanu, E.L.; Sandblad, L.; Dogterom, M.; Brunner, D.; Surrey, T. file  url
openurl 
  Title Reconstitution of a microtubule plus-end tracking system in vitro Type Journal Article
  Year 2007 Publication Nature Abbreviated Journal Nature  
  Volume 450 Issue 7172 Pages 1100-1105  
  Keywords  
  Abstract The microtubule cytoskeleton is essential to cell morphogenesis. Growing microtubule plus ends have emerged as dynamic regulatory sites in which specialized proteins, called plus-end-binding proteins (+TIPs), bind and regulate the proper functioning of microtubules. However, the molecular mechanism of plus-end association by +TIPs and their ability to track the growing end are not well understood. Here we report the in vitro reconstitution of a minimal plus-end tracking system consisting of the three fission yeast proteins Mal3, Tip1 and the kinesin Tea2. Using time-lapse total internal reflection fluorescence microscopy, we show that the EB1 homologue Mal3 has an enhanced affinity for growing microtubule end structures as opposed to the microtubule lattice. This allows it to track growing microtubule ends autonomously by an end recognition mechanism. In addition, Mal3 acts as a factor that mediates loading of the processive motor Tea2 and its cargo, the Clip170 homologue Tip1, onto the microtubule lattice. The interaction of all three proteins is required for the selective tracking of growing microtubule plus ends by both Tea2 and Tip1. Our results dissect the collective interactions of the constituents of this plus-end tracking system and show how these interactions lead to the emergence of its dynamic behaviour. We expect that such in vitro reconstitutions will also be essential for the mechanistic dissection of other plus-end tracking systems.

Subject Heading: Cell-Free System; Heat-Shock Proteins/metabolism; Intermediate Filament Proteins/metabolism; Microscopy, Fluorescence; Microtubule-Associated Proteins/*metabolism; Microtubules/*chemistry/*metabolism; *Schizosaccharomyces/chemistry/cytology; Schizosaccharomyces pombe Proteins/metabolism
 
  Call Number Serial 2223  
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Author (up) Brakefield, P.M.; Gates, J.; Keys, D.; Kesbeke, F.; Wijngaarden, P.J.; Monteiro, A.; French, V.; Carroll, S.B. file  url
openurl 
  Title Development, plasticity and evolution of butterfly eyespot patterns Type Journal Article
  Year 1996 Publication Nature Abbreviated Journal Nature  
  Volume 384 Issue 6606 Pages 236-242  
  Keywords  
  Abstract The developmental and genetic bases for the formation, plasticity and diversity of eyespot patterns in butterflies are examined. Eyespot pattern mutants, regulatory gene expression, and transplants of the eyespot developmental organizer demonstrate that eyespot position, number, size and colour are determined progressively in a developmental pathway largely uncoupled from those regulating other wing-pattern elements and body structures. Species comparisons and selection experiments suggest that the evolution of eyespot patterns can occur rapidly through modulation of different stages of this pathway, and requires only single, or very few, changes in regulatory genes.

Subject Headings: Adaptation, Biological; Animals; *Biological Evolution; Body Patterning; Butterflies/*genetics/*growth & development/metabolism; Gene Expression Regulation, Developmental; *Genes, Insect; Genes, Regulator; Homeodomain Proteins/genetics/metabolism; Insect Proteins/genetics/metabolism; Larva/genetics/growth & development/metabolism; Mutation; Phenotype; Pigmentation; Seasons; Signal Transduction; Species Specificity; Transcription Factors/genetics/metabolism; Wings, Animal/anatomy & histology/*growth & development/metabolism/transplantation

Keywords: Development, plasticity and evolution of butterfly eyespot patterns
 
  Call Number Serial 2507  
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Author (up) Cai, W.-J.; Hu, X.; Huang, W.-J.; Murrell, M.C.; Lehrter, J.C.; Lohrenz, S.E.; Chou, W.-C.; Zhai, W.; Hollibaugh, J.T.; Wang, Y.; Zhao, P.; Guo, X.; Gundersen, K.; Dai, M.; Gong, G.-C. file  url
openurl 
  Title Acidification of subsurface coastal waters enhanced by eutrophication Type Journal Article
  Year 2011 Publication Nature Geoscience Abbreviated Journal Nature Geosci  
  Volume 4 Issue 11 Pages 766-770  
  Keywords  
  Abstract Human inputs of nutrients to coastal waters can lead to the excessive production of algae, a process known as eutrophication. Microbial consumption of this organic matter lowers oxygen levels in the water1,2,3. In addition, the carbon dioxide produced during microbial respiration increases acidity. The dissolution of atmospheric carbon dioxide in ocean waters also raises acidity, a process known as ocean acidification. Here, we assess the combined impact of eutrophication and ocean acidification on acidity in the coastal ocean, using data collected in the northern Gulf of Mexico and the East China Sea--two regions heavily influenced by nutrient-laden rivers. We show that eutrophication in these waters is associated with the development of hypoxia and the acidification of subsurface waters, as expected. Model simulations, using data collected from the northern Gulf of Mexico, however, suggest that the drop in pH since pre-industrial times is greater than that expected from eutrophication and ocean acidification alone. We attribute the additional drop in pH--of 0.05 units--to a reduction in the ability of these carbon dioxide-rich waters to buffer changes in pH. We suggest that eutrophication could increase the susceptibility of coastal waters to ocean acidification.

Subject Headings: Acidification; Subsurface coastal waters; eutrophication

Keywords: Acidification of subsurface coastal waters enhanced by eutrophication
 
  Call Number Serial 2469  
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Author (up) Caldeira, K.; Wickett, M.E. file  url
openurl 
  Title Oceanography: anthropogenic carbon and ocean pH Type Journal Article
  Year 2003 Publication Nature Abbreviated Journal Nature  
  Volume 425 Issue 6956 Pages 365  
  Keywords  
  Abstract Most carbon dioxide released into the atmosphere as a result of the burning of fossil fuels will eventually be absorbed by the ocean1, with potentially adverse consequences for marine biota2,3,4. Here we quantify the changes in ocean pH that may result from this continued release of CO2 and compare these with pH changes estimated from geological and historical records. We find that oceanic absorption of CO2 from fossil fuels may result in larger pH changes over the next several centuries than any inferred from the geological record of the past 300 million years, with the possible exception of those resulting from rare, extreme events such as bolide impacts or catastrophic methane hydrate degassing.

Subject Headings: Atmosphere/chemistry; Carbon Dioxide/*analysis; Ecosystem; Hydrogen-Ion Concentration; Models, Theoretical; Oceanography; Oceans and Seas; Seawater/*chemistry; Temperature; Time Factors
 
  Call Number Serial 2335  
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Author (up) Callaway, R.M.; Brooker, R.W.; Choler, P.; Kikvidze, Z.; Lortie, C.J.; Michalet, R.; Paolini, L.; Pugnaire, F.I.; Newingham, B.; Aschehoug, E.T.; Armas, C.; Kikodze, D.; Cook, B.J. file  url
openurl 
  Title Positive interactions among alpine plants increase with stress Type Journal Article
  Year 2002 Publication Nature Abbreviated Journal Nature  
  Volume 417 Issue 6891 Pages 844-848  
  Keywords Atmospheric Pressure; Biomass; *Ecosystem; Geography; Plant Development; *Plant Physiological Phenomena; Reproduction; Species Specificity; Temperature; Stress  
  Abstract Plants can have positive effects on each other. For example, the accumulation of nutrients, provision of shade, amelioration of disturbance, or protection from herbivores by some species can enhance the performance of neighbouring species. Thus the notion that the distributions and abundances of plant species are independent of other species may be inadequate as a theoretical underpinning for understanding species coexistence and diversity. But there have been no large-scale experiments designed to examine the generality of positive interactions in plant communities and their importance relative to competition. Here we show that the biomass, growth and reproduction of alpine plant species are higher when other plants are nearby. In an experiment conducted in subalpine and alpine plant communities with 115 species in 11 different mountain ranges, we find that competition generally, but not exclusively, dominates interactions at lower elevations where conditions are less physically stressful. In contrast, at high elevations where abiotic stress is high the interactions among plants are predominantly positive. Furthermore, across all high and low sites positive interactions are more important at sites with low temperatures in the early summer, but competition prevails at warmer sites.  
  Call Number Serial 2154  
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Author (up) Challinor, A. file  url
doi  openurl
  Title Agriculture: Forecasting food Type Journal Article
  Year 2011 Publication Nature Climate Change Abbreviated Journal Nature Climate change  
  Volume 1 Issue 2 Pages 103-104  
  Keywords Climate change; Food security; Adaptation; Food systems  
  Abstract Mounting evidence that climate change will impact food security demonstrates the need to adapt food systems to future conditions. New work sheds light on the measures that will be needed to do so, and what the gains of implementing them might be.  
  Call Number Serial 774  
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Author (up) Davidson, E.A.; Trumbore, S.E.; Amundson, R. file  url
openurl 
  Title Soil warming and organic carbon content Type
  Year 2000 Publication Nature Abbreviated Journal Nature  
  Volume 408 Issue 6814 Pages 789-790  
  Keywords  
  Abstract Soils store two or three times more carbon than exists in the atmosphere as CO2, and it is thought that the temperature sensitivity of decomposing organic matter in soil partly determines how much carbon will be transferred to the atmosphere as a result of global warming1. Giardina and Ryan2 have questioned whether turnover times of soil carbon depend on temperature, however, on the basis of experiments involving isotope analysis and laboratory incubation of soils. We believe that their conclusions are undermined by methodological factors and also by their turnover times being estimated on the assumption that soil carbon exists as a single homogeneous pool, which can mask the dynamics of a smaller, temperature-dependent soil-carbon fraction. The real issue about release of carbon from soils to the atmosphere, however, is how temperature, soil water content and other factors interact to influence decomposition of soil organic matter. And, contrary to one interpretation3 of Giardina and Ryan's results, we believe that positive feedback to global warming is still a concern.

Subject Headings: Carbon/*analysis; *Climate; Greenhouse Effect; *Soil; Temperature
 
  Call Number Serial 2324  
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Author (up) Davis, G.W.; Goodman, C.S. file  url
openurl 
  Title Synapse-specific control of synaptic efficacy at the terminals of a single neuron Type Journal Article
  Year 1998 Publication Nature Abbreviated Journal Nature  
  Volume 392 Issue 6671 Pages 82-86  
  Keywords Animals; Cell Adhesion Molecules, Neuronal/genetics/metabolism; Drosophila/embryology/genetics/physiology; Motor Neurons/*physiology; Muscles/innervation/*physiology; Mutagenesis; Neuromuscular Junction/*physiology; *Synapses  
  Abstract The regulation of synaptic efficacy is essential for the proper functioning of neural circuits. If synaptic gain is set too high or too low, cells are either activated inappropriately or remain silent. There is extra complexity because synapses are not static, but form, retract, expand, strengthen, and weaken throughout life. Homeostatic regulatory mechanisms that control synaptic efficacy presumably exist to ensure that neurons remain functional within a meaningful physiological range. One of the best defined systems for analysis of the mechanisms that regulate synaptic efficacy is the neuromuscular junction. It has been shown, in organisms ranging from insects to humans, that changes in synaptic efficacy are tightly coupled to changes in muscle size during development. It has been proposed that a signal from muscle to motor neuron maintains this coupling. Here we show, by genetically manipulating muscle innervation, that there are two independent mechanisms by which muscle regulates synaptic efficacy at the terminals of single motor neurons. Increased muscle innervation results in a compensatory, target-specific decrease in presynaptic transmitter release, implying a retrograde regulation of presynaptic release. Decreased muscle innervation results in a compensatory increase in quantal size.  
  Call Number Serial 1320  
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