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11.
Ann Carla Staver Paulo M. Brando Jos Barlow Douglas C. Morton C.E. Timothy Paine Yadvinder Malhi Alejandro Araujo Murakami Jhon del Aguila Pasquel 《Ecology letters》2020,23(1):99-106
Understory fires represent an accelerating threat to Amazonian tropical forests and can, during drought, affect larger areas than deforestation itself. These fires kill trees at rates varying from < 10 to c. 90% depending on fire intensity, forest disturbance history and tree functional traits. Here, we examine variation in bark thickness across the Amazon. Bark can protect trees from fires, but it is often assumed to be consistently thin across tropical forests. Here, we show that investment in bark varies, with thicker bark in dry forests and thinner in wetter forests. We also show that thinner bark translated into higher fire‐driven tree mortality in wetter forests, with between 0.67 and 5.86 gigatonnes CO2 lost in Amazon understory fires between 2001 and 2010. Trait‐enabled global vegetation models that explicitly include variation in bark thickness are likely to improve the predictions of fire effects on carbon cycling in tropical forests. 相似文献
12.
Rodrigo S. Lacruz José María Bermúdez de Castro María Martinón-Torres Paul O’Higgins Michael L. Paine Eudald Carbonell Juan Luis Arsuaga Timothy G. Bromage 《PloS one》2013,8(6)
The modern human face differs from that of our early ancestors in that the facial profile is relatively retracted (orthognathic). This change in facial profile is associated with a characteristic spatial distribution of bone deposition and resorption: growth remodeling. For humans, surface resorption commonly dominates on anteriorly-facing areas of the subnasal region of the maxilla and mandible during development. We mapped the distribution of facial growth remodeling activities on the 900–800 ky maxilla ATD6-69 assigned to H. antecessor, and on the 1.5 My cranium KNM-WT 15000, part of an associated skeleton assigned to African H. erectus. We show that, as in H. sapiens, H. antecessor shows bone resorption over most of the subnasal region. This pattern contrasts with that seen in KNM-WT 15000 where evidence of bone deposition, not resorption, was identified. KNM-WT 15000 is similar to Australopithecus and the extant African apes in this localized area of bone deposition. These new data point to diversity of patterns of facial growth in fossil Homo. The similarities in facial growth in H. antecessor and H. sapiens suggest that one key developmental change responsible for the characteristic facial morphology of modern humans can be traced back at least to H. antecessor. 相似文献
13.
Cyril Rauch Stuart W. Paine Peter Littlewood 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Failure of treatment in over 90% of patients with metastatic cancer is due to acquired MDR. P-glycoprotein (Pgp) remains the archetypal drug membrane transporter expressed in many MDR cancer cells. Albeit the ATPase activity of Pgp is triggered by the presence of drug in the membrane, it is commonly assumed that when two drug molecules meet the same Pgp the protein cannot handle them efficiently due to steric effects and as a result the ATPase activity drops. However it is also possible that drug accumulating in the lipid-phase may affect the membrane in such a way that it imposes the mechanical closure of transporters by opposing the force mediated by ATP consumption. In this context, long range interactions between drug and membrane proteins could exist.Methods
Recent data concerning Pgp structure have allowed us to formalize this hypothesis and we present a physico-mathematical model that is not based on predictive QSAR or other empirical methods applied to experimental data.Results
Long range mechanical interactions between Pgp and drugs are predicted to occur at an external concentration of drug ~ 10–100 μM as previously determined experimentally at which concentration ~ 50% of transporters should be rendered inactive.Conclusion
Distance interaction(s) between Pgp and drugs exist explaining an ill-defined effect concerning the ability of any drug to inhibit Pgp once a threshold concentration in the membrane has been reached.General significance
Potential application of the theory in the field of pharmacology concentrating on the notion of molecular promiscuity and toxicity in drug discovery prediction is discussed. 相似文献14.
Peter Kivisto I.C. Jarvie J. Milton Yinger Marc V. Levine Robert Paine 《Ethnic and racial studies》2013,36(1):167-177
Andrew Hacker, TWO NATIONS: BLACK AND WHITE, SEPARATE, HOSTILE, UNEQUAL, New York: Charles Scribner's Sons, 1992, vii + 257 pp., $24.95. Catherine Silk and John Silk, RACISM AND ANTI‐RACISM IN AMERICAN POPULAR CULTURE, Manchester: Manchester University Press, 1990, x + 186 pp., £27.50. Therese Daniels and Jane Gerson (eds), THE COLOUR BLACK, BLACK IMAGES IN BRITISH TELEVISION, London: BFI Publishing, 1989, 160 pp., £4.95 (paper). Jim Pines and Paul Willemen (eds), QUESTIONS OF THIRD CINEMA, London: BFI Publishing, 1989, x + 246 pp., £7.95 (paper). David R. Roediger, THE WAGES OF WHITENESS: RACE AND THE MAKING OF THE AMERICAN WORKING CLASS, London: Verso, 1991, 191 pp., £12.95 (paper). William Cohen, AT FREEDOM'S EDGE: BLACK MOBILITY AND THE SOUTHERN WHITE QUEST FOR RACIAL CONTROL, 1861–1915, Baton Rouge: Louisiana State University Press, 1991, 340 pp., $42.50. Robert L. Cooper, LANGUAGE PLANNING AND SOCIAL CHANGE, Cambridge: Cambridge University Press, 1990, 216 pp., £27.50, £9.95 (paper). Emmanual Sivan and Menachem Friedman (eds), RELIGIOUS RADICALISM AND POLITICS IN THE MIDDLE EAST, Albany: State University of New York Press, 1990, 244 pp., n.p. Eliezer Ben‐Rafael and Stephen Sharot, ETHNICITY, RELIGION, AND CLASS IN ISRAELI SOCIETY, Cambridge: Cambridge University Press, 1991, 287 pp., £32.50. 相似文献
15.
Elodie A. Courtois Kyle G. Dexter Charles Eliot Timothy Paine Didier Stien Julien Engel Christopher Baraloto Jérôme Chave 《Ecology and evolution》2016,6(9):2854-2864
Plant responses to natural enemies include formation of secondary metabolites acting as direct or indirect defenses. Volatile terpenes represent one of the most diverse groups of secondary metabolites. We aimed to explore evolutionary patterns of volatile terpene emission. We measured the composition of damage‐induced volatile terpenes from 202 Amazonian tree species, spanning the angiosperm phylogeny. Volatile terpenes were extracted with solid‐phase micro extraction and desorbed in a gas chromatography–mass spectrometry for compound identification. The chemical diversity of the terpene blend showed a strong phylogenetic signal as closely related species emitted a similar number of compounds. Closely related species also tended to have compositionally similar blends, although this relationship was weak. Meanwhile, the ability to emit a given compound showed no significant phylogenetic signal for 200 of 286 compounds, indicating a high rate of diversification in terpene synthesis and/or great variability in their expression. Three lineages (Magnoliales, Laurales, and Sapindales) showed exceptionally high rates of terpene diversification. Of the 70 compounds found in >10% of their species, 69 displayed significant correlated evolution with at least one other compound. These results provide insights into the complex evolutionary history of volatile terpenes in angiosperms, while highlighting the need for further research into this important class of compounds. 相似文献
16.
There's no place like home: seedling mortality contributes to the habitat specialisation of tree species across Amazonia 总被引:1,自引:0,他引:1
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Claire Fortunel C. E. Timothy Paine Paul V. A. Fine Italo Mesones Jean‐Yves Goret Benoit Burban Jocelyn Cazal Christopher Baraloto 《Ecology letters》2016,19(10):1256-1266
Understanding the mechanisms generating species distributions remains a challenge, especially in hyperdiverse tropical forests. We evaluated the role of rainfall variation, soil gradients and herbivory on seedling mortality, and how variation in seedling performance along these gradients contributes to habitat specialisation. In a 4‐year experiment, replicated at the two extremes of the Amazon basin, we reciprocally transplanted 4638 tree seedlings of 41 habitat‐specialist species from seven phylogenetic lineages among the three most important forest habitats of lowland Amazonia. Rainfall variation, flooding and soil gradients strongly influenced seedling mortality, whereas herbivory had negligible impact. Seedling mortality varied strongly among habitats, consistent with predictions for habitat specialists in most lineages. This suggests that seedling performance is a primary determinant of the habitat associations of adult trees across Amazonia. It further suggests that tree diversity, currently mostly harboured in terra firme forests, may be strongly impacted by the predicted climate changes in Amazonia. 相似文献
17.
C. W. Bird B. C. Baculis J. J. Mayfield G. J. Chavez T. Ontiveros D. J. Paine A. J. Marks A. L. Gonzales D. Ron C. F. Valenzuela 《Genes, Brain & Behavior》2019,18(3)
Prenatal exposure to alcohol causes a wide range of deficits known as fetal alcohol spectrum disorders (FASDs). Many factors determine vulnerability to developmental alcohol exposure including timing and pattern of exposure, nutrition and genetics. Here, we characterized how a prevalent single nucleotide polymorphism in the human brain‐derived neurotrophic factor (BDNF) gene (val66met) modulates FASDs severity. This polymorphism disrupts BDNF's intracellular trafficking and activity‐dependent secretion, and has been linked to increased incidence of neuropsychiatric disorders such as depression and anxiety. We hypothesized that developmental ethanol (EtOH) exposure more severely affects mice carrying this polymorphism. We used transgenic mice homozygous for either valine (BDNFval/val) or methionine (BDNFmet/met) in residue 68, equivalent to residue 66 in humans. To model EtOH exposure during the second and third trimesters of human pregnancy, we exposed mice to EtOH in vapor chambers during gestational days 12 to 19 and postnatal days 2 to 9. We found that EtOH exposure reduces cell layer volume in the dentate gyrus and the CA1 hippocampal regions of BDNFmet/met but not BDNFval/val mice during the juvenile period (postnatal day 15). During adulthood, EtOH exposure reduced anxiety‐like behavior and disrupted trace fear conditioning in BDNFmet/met mice, with most effects observed in males. EtOH exposure reduced adult neurogenesis only in the ventral hippocampus of BDNFval/val male mice. These studies show that the BDNF val66met polymorphism modulates, in a complex manner, the effects of developmental EtOH exposure, and identify a novel genetic risk factor that may regulate FASDs severity in humans. 相似文献
18.
19.
Colin Umeda Michele Eatough Jones Timothy Paine 《Entomologia Experimentalis et Applicata》2019,167(9):820-825
Polyphagous shot hole borer (PSHB), Euwallacea whitfordiodendrus (Schedl) (Coleoptera: Curculionidae, Scolytinae), is an ambrosia beetle that has recently invaded southern California, USA. This beetle successfully attacks and reproduces in a multitude of tree species. As direct control methods are limited, we investigated cultural management options, and sought to determine whether irrigation affects the number of attacks host trees experienced. If irrigation plays a role, cultural control methods could be recommended to managers and growers. Three separate experiments were conducted that monitored the number of attacks on trees with different levels of irrigation. Two experiments examined PSHB attacks in established landscape trees where irrigation was either present or absent. A third experiment used young potted box elder with irrigation controlled with timed emitters. In all three experiments, the level of irrigation received by the trees did not affect the number of attacks. The results suggest that changes in irrigation practices do not affect risk from PSHB attack. 相似文献
20.