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21.
Heterosis is of utmost economic importance in plant breeding. However, its underlying molecular causes are still unknown. Given the numerous advantages of Arabidopsis thaliana as a model species in plant genetics and genomics, we assessed the extent of heterosis in this species using five hybrids derived from five ecotypes. Parents, F(1) and F(2), generations in both reciprocal forms were grown in a greenhouse experiment with four replications. Mid-parent heterosis (MPH) and best-parent heterosis (BPH) averaged across hybrids were surprisingly high for biomass yield (MPH: 60.3%; BPH: 32.9%) and rosette diameter (MPH: 49.4%; BPH: 34.8%), but smaller for flowering date (MPH: 27.5%; BPH: 18.5%), seed yield (MPH: 18.9%; BPH: 1.7%), and yield components. Individual hybrids varied considerably in their MPH and BPH values for all traits, one cross displaying 140.1% MPH for biomass yield. MPH was not associated with parental genetic distance determined from molecular markers. Reciprocal effects were significant only in a few cases. With a proper choice of hybrids, our results encourage the use of Arabidopsis as a model species for investigating the molecular causes of heterosis. 相似文献
22.
Molecular cloning, sequencing of the human genome, and other major advances in biomedical research have contributed substantially to our understanding of autoimmune disease. Nevertheless, to date, such advances have failed to reveal the etiology of or yield curative therapies for autoimmune disease. New approaches are needed. Proteomics, the large-scale study of expression and function of proteins that compose our tissues and mediate disease, represents a powerful and promising strategy. We developed protein and peptide arrays to profile autoantibody responses in autoimmune disease. Protein and peptide array analysis of autoimmune samples is revealing human and pathogen proteins involved in initiation and perpetuation of autoimmunity. Proteomic determination of autoantibody profiles can be utilized for diagnosis, prognostication, and guiding tolerizing therapy for autoimmune disease. 相似文献
23.
SMN-mediated assembly of RNPs: a complex story 总被引:18,自引:0,他引:18
Although many RNA-protein complexes or ribonucleoproteins (RNPs) assemble spontaneously in vitro, little is known about how they form in the environment of a living cell. Insight into RNP assembly has come unexpectedly from functional analyses of the survival motor neuron (SMN) protein, a gene product that is affected in the neuromuscular disease spinal muscular atrophy. These studies show that the assembly of spliceosomal U-rich small nuclear RNPs in vivo depends on the activity of two large protein complexes, one of which contains the SMN protein. These complexes might also facilitate the assembly of other cellular RNPs. 相似文献
24.
Protein arrays provide a powerful approach to study autoimmune disease. Autoimmune responses activate B cells to produce autoantibodies that recognize self-molecules termed autoantigens, many of which are proteins or protein complexes. Protein arrays enable profiling of the specificity of autoantibody responses against panels of peptides and proteins representing known autoantigens as well as candidate autoantigens. In addition to identifying autoantigens and mapping immunodominant epitopes, proteomic analysis of autoantibody responses will further enable diagnosis, prognosis, and tailoring of antigen-specific tolerizing therapy. 相似文献
25.
During apoptosis, the U1-70K protein, a component of the spliceosomal U1 snRNP complex, is specifically cleaved by the enzyme caspase-3, converting it into a C-terminally truncated 40-kDa fragment. In this study, we show that the 40-kDa U1-70K fragment is still associated with the complete U1 snRNP complex, and that no obvious modifications occur with the U1 snRNP associated proteins U1A, U1C and Sm-B/B'. Furthermore, it is described for the first time that the U1 snRNA molecule, which is the backbone of the U1 snRNP complex, is modified during apoptosis by the specific removal of the first 5 - 6 nucleotides including the 2,2, 7-trimethylguanosine (TMG) cap. The observations that U1 snRNA cleavage is very specific (no such modifications were detected for the other U snRNAs tested) and that U1 snRNA cleavage is markedly inhibited in the presence of caspase inhibitors, indicate that an apoptotically activated ribonuclease is responsible for the specific modification of U1 snRNA during apoptosis. 相似文献
26.
David J Bonfil Michal Ronen-Tarazi Dieter Sültemeyer Judy Lieman-Hurwitz Daniella Schatz Aaron Kaplan 《FEBS letters》1998,430(3):17199
Cyanobacteria possess an inducible mechanism which enables them to concentrate inorganic carbon (Ci) within the cells. An inactivation library was used to raise the high-CO2-requiring mutant of Synechococcus PCC 7942, IL-2, impaired in HCO−3 transport. Analysis of the relevant genomic DNA detected several modifications, probably due to the single crossover recombination, leading to inactivation of ORF467 (designated ictB) in IL-2. IctB contains 10 trans-membrane regions and is homologous to several transport-related proteins from various organisms. Kinetic analyses of HCO−3 uptake in the wild type and IL-2 suggested the presence of two or three HCO−3 carriers exhibiting different affinities to HCO−3. 相似文献
27.
Peter von Dassow Uwe John Hiroyuki Ogata Ian Probert El Mahdi Bendif Jessica U Kegel Stéphane Audic Patrick Wincker Corinne Da Silva Jean-Michel Claverie Scott Doney David M Glover Daniella Mella Flores Yeritza Herrera Magali Lescot Marie-José Garet-Delmas Colomban de Vargas 《The ISME journal》2015,9(6):1365-1377
Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers. 相似文献
28.
Daniella Braz Parente Fernando Fernandes Paiva Jaime Araújo Oliveira Neto Lilian Machado-Silva Fatima Aparecida Ferreira Figueiredo Valeria Lanzoni Carlos Frederico Ferreira Campos Pedro Emmanuel Alvarenga Americano do Brasil Marilia de Brito Gomes Renata de Mello Perez Rosana Souza Rodrigues 《PloS one》2015,10(5)
ObjectiveTo evaluate the capability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) to assess steatohepatitis and fibrosis determined by histopathology in type 2 diabetic patients.MethodsFifty-nine type 2 diabetic patients (49 women, 10 men; mean age, 54 ± 9 years) were submitted to liver biopsy for the evaluation of non-alcoholic fatty liver disease (NAFLD) and underwent DWI on a 3.0T MR system using 10 b values. Institutional approval and patient consent were obtained. Pure molecular-based (D), perfusion-related (D*), and vascular fraction (f) were calculated using a double exponential model and least squares curve fitting. D, D*, and f were compared between patients with and without steatohepatitis and between patients with and without fibrosis. The variables were compared by using the Ranksum test and Student t-test.ResultsSteatohepatitis was observed in 22 patients and fibrosis in 16 patients. A lower D median (0.70 s/mm2 vs. 0.83 s/mm2, p<0.05) and a lower D* median (34.39 s/mm2 vs. 45.23 s/mm2, p<0.05) were observed among those with steatohepatitis. A lower D median (0.70 s/mm2 vs. 0.82 s/mm2, p<0.05) and a lower D* median (35.01 s/mm2 vs. 44.76 s/mm2, p=0.05) were also observed among those with fibrosis.ConclusionIVIM-DWI has the potential to aid in the characterization of steatohepatitis and fibrosis. 相似文献
29.
Pay-for-performance programs are often aimed to improve the management of chronic diseases. We evaluate the impact of a local pay for performance programme (QOF+), which rewarded financially more ambitious quality targets (‘stretch targets’) than those used nationally in the Quality and Outcomes Framework (QOF). We focus on targets for intermediate outcomes in patients with cardiovascular disease and diabetes. A difference-in-difference approach is used to compare practice level achievements before and after the introduction of the local pay for performance program. In addition, we analysed patient-level data on exception reporting and intermediate outcomes utilizing an interrupted time series analysis. The local pay for performance program led to significantly higher target achievements (hypertension: p-value <0.001, coronary heart disease: p-values <0.001, diabetes: p-values <0.061, stroke: p-values <0.003). However, the increase was driven by higher rates of exception reporting (hypertension: p-value <0.001, coronary heart disease: p-values <0.03, diabetes: p-values <0.05) in patients with all conditions except for stroke. Exception reporting allows practitioners to exclude patients from target calculations if certain criteria are met, e.g. informed dissent of the patient for treatment. There were no statistically significant improvements in mean blood pressure, cholesterol or HbA1c levels. Thus, achievement of higher payment thresholds in the local pay for performance scheme was mainly attributed to increased exception reporting by practices with no discernable improvements in overall clinical quality. Hence, active monitoring of exception reporting should be considered when setting more ambitious quality targets. More generally, the study suggests a trade-off between additional incentive for better care and monitoring costs. 相似文献
30.
Gabriela B. Gomez Nicola Foster Daniella Brals Heleen E. Nelissen Oladimeji A. Bolarinwa Marleen E. Hendriks Alexander C. Boers Diederik van Eck Nicole Rosendaal Peju Adenusi Kayode Agbede Tanimola M. Akande Michael Boele van Hensbroek Ferdinand W. Wit Catherine A. Hankins Constance Schultsz 《PloS one》2015,10(9)