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951.
María Victoria Alarcón Alberto Lloret-Salamanca Pedro Gaspar Lloret Domingo José Iglesias Manuel Talón Julio Salguero 《Plant signaling & behavior》2009,4(12):1154-1156
During the first days of development, maize roots showed considerable variation in the production of ethylene and the rate of elongation. As endogenous ethylene increases, root elongation decreases. When these roots are treated with the precursor of ethylene aminocyclopropane- 1-carboxylic acid (ACC), or inhibitors of ethylene biosynthesis 2-aminoethoxyvinyl glycine (AVG) or cobalt ions, the root elongation is also inhibited. Because of root growth diminishes at high or reduced endogenous ethylene concentrations, it appears that this phytohormone must be maintained in a range of concentrations to support normal root growth. In spite of its known role as inhibitor of ethylene action, silver thiosulphate (STS) does not change significantly the root elongation rate. This suggests that the action of ethylene on root elongation should occur, at least partially, by interaction with other growth regulators.Key words: 2-aminoethoxyvinyl glycine, cobalt, ethylene, root elongation, silver thiosulphate, Zea mays 相似文献
952.
953.
Hannah Kuper Oluwarantimi Atijosan Dorothea Rischewski Victoria Simms Chris Lavy 《PloS one》2009,4(11)
Background
In 1994 there was a horrific genocide in Rwanda following years of tension, resulting in the murder of at least 800,000 people. Although many people were injured in addition to those killed, no attempt has been made to assess the lasting burden of physical injuries related to these events. The aim of this study was to estimate the current burden of musculoskeletal impairment (MSI) attributable to the 1994 war and related violence.Methodology/Principal Findings
A national cross-sectional survey of MSI was conducted in Rwanda. 105 clusters of 80 people were selected through probability proportionate to size sampling. Households within clusters were selected through compact segment sampling. Enumerated people answered a seven-question screening test to assess whether they might have an MSI. Those who were classed as potential cases in the screening test were examined and interviewed by a physiotherapist, using a standard protocol that recorded the site, nature, cause, and severity of the MSI. People with MSI due to trauma were asked whether this trauma occurred during the 1990–1994 war or during the episodes that preceded or followed this war. Out of 8,368 people enumerated, 6,757 were available for screening and examination (80.8%). 352 people were diagnosed with an MSI (prevalence = 5.2%, 95% CI = 4.5–5.9%). 106 cases of MSI (30.6%) were classified as resulting from trauma, based on self-report and the physiotherapist''s assessment. Of these, 14 people (13.2%) reported that their trauma-related MSI occurred during the 1990–1994 war, and a further 7 (6.6%) that their trauma-related MSI occurred during the violent episodes that preceded and followed the war, giving an overall prevalence of trauma-related MSI related to the 1990–1994 war of 0.3% (95% CI = 0.2–0.4%).Conclusions/Significance
A decade on, the overall prevalence of MSI was relatively high in Rwanda but few cases appeared to be the result of the 1994 war or related violence. 相似文献954.
Sílvia Castro Victoria Ferrero João Loureiro Xavier Espadaler Paulo Silveira Luis Navarro 《Plant Ecology》2010,207(2):359-372
This study assesses the dispersal mechanisms of the narrow endemic Polygala vayredae, analysing the functioning of its dispersal syndromes (anemochory and myrmecochory), the spatio-temporal variability of the
disperser assemblage, foraging behaviour and dispersal ability, and the role of the elaiosome in ant attraction and seed germination.
The dispersion of diaspores begins when either (1) capsules or seeds fall beneath the mother plant (barochory) or (2) the
seeds are directly collected in the suspended capsules by ants (myrmecochory). As capsules frequently open and expose/disseminate
seeds before leaving the mother plant, the adaptation for anemochory appears to be reduced and rarely functional, possibly
with only occasional events of long-distance dispersal (e.g. under extreme weather conditions). P. vayredae is essentially myrmecochorous and a diverse array of ant species are involved in seed manipulation, with the elaiosome playing
a major role in ant attraction. From the plant’s perspective for dispersal, the majority of ant species had a positive interaction
with the seeds, but negative and potential neutral interactions were also observed. Overall, dispersal distances were limited
and were mainly determined by ant body size. The frequency of interactions and the ant assemblage varied significantly both
spatially and temporally, and these factors may have an effect on directing or disrupting the selection of plant traits. Low
seed predation and similar germination rates of intact seeds compared with seeds without elaiosome indicate that seed predator
avoidance and seed germination improvement after ant manipulation are not among the selective advantages of myrmecochory operating
at present. Dispersal mechanisms that enhance seed dispersal within the population and only occasionally lead to long-distance
dispersal events, along with the rarity and patchiness of suitable habitats, may be the main factors explaining the actual
density and narrow distribution of this species. 相似文献
955.
956.
957.
Boys ML Schretzman LA Chandrakumar NS Tollefson MB Mohler SB Downs VL Penning TD Russell MA Wendt JA Chen BB Stenmark HG Wu H Spangler DP Clare M Desai BN Khanna IK Nguyen MN Duffin T Engleman VW Finn MB Freeman SK Hanneke ML Keene JL Klover JA Nickols GA Nickols MA Steininger CN Westlin M Westlin W Yu YX Wang Y Dalton CR Norring SA 《Bioorganic & medicinal chemistry letters》2006,16(4):839-844
We describe a series of 1,2,4-oxadiazoles, which are potent antagonists of the integrin alpha(v)beta3 and, in addition, show selectivity relative to the other beta3 integrin alpha(IIb)beta3. In whole cells, the majority of these analogs also demonstrated modest selectivity against other alpha(v) integrins such as alpha(v)beta1 and alpha(v)beta6. 相似文献
958.
Masterson LA Spanswick VJ Hartley JA Begent RH Howard PW Thurston DE 《Bioorganic & medicinal chemistry letters》2006,16(2):252-256
The design, synthesis and evaluation of four novel pyrrolo[2,1-c][1,4]benzodiazepine (PBD) prodrugs (1a,b and 2a,b; ) for potential use in carboxypeptidase G2 (CPG2)-based antibody-directed enzyme prodrug therapy (ADEPT) is reported. Although all four prodrugs were shown to be less cytotoxic than the released parent PBDs 3 and 4, the urea prodrugs 1b and 2b were found to be too unstable for use in ADEPT, whereas carbamates 1a and 2a are both stable in an aqueous environment and are good substrates for CPG2. 相似文献
959.
Peregrin S Jurado-Pueyo M Campos PM Sanz-Moreno V Ruiz-Gomez A Crespo P Mayor F Murga C 《Current biology : CB》2006,16(20):2042-2047
p38 Mitogen-activated protein kinases (MAPK) are a family of Ser/Thr kinases that regulate important cellular processes such as stress responses, differentiation, and cell-cycle control . Activation of MAPK is achieved through a linear signaling cascade in which upstream kinases (MAPKKs) dually phosphorylate MAPKs at a conserved 3-amino-acid motif (Thr-X-Tyr) . G-protein-coupled receptor kinases (GRKs) are known to selectively phosphorylate G-protein-coupled receptors (GPCRs) and thus trigger desensitization . We report that GRK2 is a novel inactivating kinase of p38MAPK. p38 associates with GRK2 endogenously and is phosphorylated by GRK2 at Thr-123, a residue located at its docking groove. Mimicking phosphorylation at this site impairs the binding and activation of p38 by MKK6 and diminishes the capacity of p38 to bind and phosphorylate its substrates. Accordingly, p38 activation is decreased or increased when cellular GRK2 levels are enhanced or reduced, respectively. Changes in GRK2 levels and activity can modify p38-dependent processes such as differentiation of preadipocytic cells and LPS-induced cytokine release, enhanced in macrophages from GRK2(+/-) mice. Phosphorylation of p38 at a region key for its interaction with different partners uncovers a new mechanism for the regulation of this important family of kinases. 相似文献
960.
A recent study suggests that the opportunistic pathogen Pseudomonas aeruginosa can actively monitor the host immune system. The P. aeruginosa outer membrane protein OprF was found to bind specifically to the cytokine interferon-gamma (IFN-gamma), and this interaction upregulated production of virulence factors through a cell-cell communication system known as quorum sensing (QS). Taken together with previous findings that P. aeruginosa QS can alter the host immune response (e.g. by activation of IFN-gamma), these data illustrate an exciting new element of bacteria-host interactions in which the P. aeruginosa quorum-sensing system both senses and modulates the host immune state. 相似文献