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The A.T-DNA-binding domain of mammalian high mobility group I chromosomal proteins. A novel peptide motif for recognizing DNA structure. 总被引:37,自引:0,他引:37
We have determined the domains of the mammalian high mobility group (HMG)I chromosomal proteins necessary and sufficient for binding to the narrow minor groove of stretches of A.T-rich DNA. Three highly conserved regions within each of the known HMG-I proteins is closely related to the consensus sequence T-P-K-R-P-R-G-R-P-K-K. A synthetic oligopeptide corresponding to this consensus "binding domain" (BD) sequence specifically binds to substrate DNA in a manner similar to the intact HMG-I proteins. Molecular Corey-Pauling-Koltun model building and computer simulations employing energy minimization programs to predict structure suggest that the consensus BD peptide has a secondary structure similar to the antitumor and antiviral drugs netropsin and distamycin and to the dye Hoechst 33258. In vitro these ligands, which also preferentially bind to A.T-rich DNA, have been demonstrated to effectively compete with both the BD peptide and the HMG-I proteins for DNA binding. The BD peptide also contains novel structural features such as a predicted Asx bend or "hook" at its amino-terminal end and laterally projecting cationic Arg/Lys side chains or "bristles" which may contribute to the binding properties of the HMG-I proteins. The predicted BD peptide structure, which we refer to as the "A.T-hook," represents a previously undescribed DNA-binding motif capable of binding to the minor groove of stretches of A.T base pairs. 相似文献
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Quantification of Indole-3-Acetic Acid in Dark-Grown Seedlings of the Diageotropica and Epinastic Mutants of Tomato (Lycopersicon esculentum Mill.) 总被引:4,自引:4,他引:0 下载免费PDF全文
Endogenous indoleacetic acid (IAA) levels were examined in 7-day-old, dark-grown tomato seedlings (Lycopersicon esculentum Mill. cv VFN8), and in two single-gene mutants, Epinastic and diageotropica. Gas chromatography-mass spectrometry was employed to quantify IAA using 13C6-[benzene ring]indoleacetic acid as internal standard. IAA concentrations ranged from 89 to 134 nanograms per gram dry weight and were not significantly different for the three genotypes. Ethylene over-production by dark-grown Epi seedlings is not likely to result from increased IAA. Assuming similar recovery percentages for each genotype, indole-3-ethanol, a purported storage form of IAA, was identified by GC-MS and found to be more prevalent in the parent tomato, VFN8, with only trace amounts observed in Epi. No IEt was detected by high performance liquid chromatography/fluorescence in dgt (detection limit >100 picograms). 相似文献
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The effects of atmospheric CO2 enrichment and root restriction on photosynthetic characteristics and growth of banana (Musa sp. AAA cv. Gros Michel) plants were investigated. Plants were grown aeroponically in root chambers in controlled environment glasshouse rooms at CO2 concentrations of 350 or 1 000 μmol CO2 mol-1. At each CO2 concentration, plants were grown in large (2001) root chambers that did not restrict root growth or in small (20 1) root chambers that restricted root growth. Plants grown at 350 μmol CO2 mol-1 generally had a higher carboxylation efficiency than plants grown at 1 000 μmol CO2 mol-1 although actual net CO2 assimilation (A) was higher at the higher ambient CO2 concentration due to increased intercellular CO2 concentrations (Ci resulting from CO2 enrichment. Thus, plants grown at 1 000 μmol CO2 mol-1 accumulated more leaf area and dry weight than plants grown at 350 μmol CO2 mol-1. Plants grown in the large root chambers were more photosynthetically efficient than plants grown in the small root chambers. At 350 μmol CO2 mol-1, leaf area and dry weights of plant organs were generally greater for plants in the large root chambers compared to those in the small root chambers. Atmospheric CO2 enrichment may have compensated for the effects of root restriction on plant growth since at 1 000 μmol CO2 mol-1 there was generally no effect of root chamber size on plant dry weight. 相似文献
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Jesper Kj?rgaard Lone Graff Stensballe Nina Marie Birk Thomas N?rrelykke Nissen Kim Thestrup Foss Lisbeth Marianne Th?stesen Gitte Thybo Pihl Andreas Andersen Poul-Erik Kofoed Ole Pryds Gorm Greisen 《PloS one》2016,11(4)
ObjectivesTo assess the non-specific effect of Bacillus Calmette-Guérin (BCG) vaccination at birth on psychomotor development.DesignThis is a pre-specified secondary outcome from a randomised, clinical trial.SettingMaternity units and paediatric wards at three university hospitals in Denmark.ParticipantsChildren born at gestational age (GA) 32 weeks and above. All women planning to give birth at the three sites were invited during the recruitment period. Out of 4262 randomised children, 144 were premature (GA < 37 weeks). There were 2129 children (71 premature) randomised to BCG and 2133 randomised (73 premature) to the control group.InterventionsBCG vaccination 0.05 ml was given intradermally in the upper left arm at the hospital within seven days of birth. Children in the control group did not receive any intervention. Parents were not blinded to allocation.ResultsThe mean difference in ASQ score at 12 months adjusted for age and prematurity was -0.7 points (BCG vs. control, 95% confidence interval; -3.7 to 2.4), p = 0.67, corresponding to an effect size of Cohen’s d = -0.015 (-0.082 to 0.052). The mean difference in ASQ score for premature children at 22 months was -7.8 points (-20.6 to 5.0, p = 0.23), d = -0.23 (-0.62 to 0.15).ConclusionsA negative non-specific effect of BCG vaccination at birth on psychomotor development was excluded in term children.
Trial Registration
ClinicalTrials.gov NCT01694108相似文献68.
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Utilization of leaf, stem, root, and latex starch was monitored in Euphorbia esula L. plants. Leaf, stem, and root starch decreased rapidly during a 52 day light starvation period while latex starch did not. Scanning electron and light microscope studies provided additional evidence that no changes in latex starch granules had occurred. Amylase activity (6.6 units per milligram protein) could be isolated from latex. However, latex starch granules were extremely resistant to enzymic hydrolysis by latex amylases, Bacillus subtilis α-amylase, and by amyloglucosidase from Aspergillus niger. Results indicate that latex starch grains do not function as utilizable carbohydrate in this species under these conditions. 相似文献