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51.
de O Manes CL Beeckman T Ritsema T Van Montagu M Goethals K Holsters M 《Journal of plant research》2004,117(2):139-145
Arabidopsis thaliana (L.) Heynh. plants were challenged with Rhodococcus fascians at several developmental stages and using different inoculation procedures. A variety of morphological alterations was scored on the infected plants; some of them resembled phenotypes of A. thaliana mutants in their shoot apical meristem (SAM) organization. Infection with R. fascians did not affect SAM organization in wild type nor in SAM mutants. Anatomical studies on the new organs formed after infection with R. fascians demonstrated extensive bacterial colonization. Colonization and concomitant production of specific signals are the likely cause of malformations. 相似文献
52.
A systematic analysis of the N-glycosylation of the catalytic domain of cellobiohydrolase I (Cel7A or CBH I) isolated from several Trichoderma reesei strains grown in minimal media was performed. Using a combination of chromatographic, electrophoretic, and mass spectrometric methods, the presence of glucosylated and phosphorylated oligosaccharides on the three N-glycosylation sites of Cel7A core protein (from T. reesei strains Rut-C30 and RL-P37) confirms previous findings. With N-glycans isolated from other strains, no end-capping glucose could be detected. Phosphodiester linkages were however found in proteins from each strain and these probably occur on both the alpha1-3 and the alpha1-6 branch of the high-mannose oligosaccharide tree. Evidence is also presented for the occurrence of mannobiosyl units on the phosphodiester linkage. Therefore the predominant N-glycans on Cel7A can be represented as (ManP)(0-1)GlcMan(7-8)GlcNAc2 for the hyperproducing Rut-C30 and RL-P37 mutants and as (Man(1-2)P)(0-1-2)Man(5-6-7)GlcNAc2 for the wild-type strain and the other mutants. As shown by ESI-MS, random substitution of these structures on the N-glycosylation sites explains the heterogeneous glycoform population of the isolated core domains. PAG-IEF separates up to five isoforms, resulting from posttranslational modification of Cel7A with mannosyl phosphodiester residues at the three distinct sites. This study clearly shows that posttranslational phosphorylation of glycoproteins is not atypical for Trichoderma sp. and that, in the case of the Rut-C30 and RL-P37 strains, the presence of an end-capped glucose residue at the alpha1-3 branch apparently hinders a second mannophoshoryl transfer. 相似文献
53.
de Groot P Weterings K de Been M Wittink F Hulzink R Custers J van Herpen M Wullems G 《Plant molecular biology》2004,55(5):715-726
54.
The process of cytokinesis can be divided into two stages: the assembly and constriction of an actomyosin ring giving rise to a narrow intracellular canal and the final breaking and resealing of this canal. Mutations in several genes of Caenorhabditis elegans disrupt the spindle midzone (anti-parallel microtubules and associated proteins that form between the spindle poles) and give rise to failures in the completion of cytokinesis. We show that loss of function of spd-1 causes midzone disruptions, although cytokinesis generally completes. SPD-1 is a conserved microtubule-bundling protein that localizes to the midzone and also to microtubule bundles in the cytoplasm. The midzone localization of SPD-1 is perturbed in embryos depleted of other midzone components, yet the cytoplasmic bundles are not affected. We found that two other midzone components also localize to the ingressing furrow in wild-type embryos; when SPD-1 is depleted, there is no visible midzone, and only this furrow localization remains. SPD-1 differs from other midzone components in that it is essential for the integrity of the midzone, yet not for cytokinesis. Also, it can localize to the midzone when other midzone components are depleted, suggesting that SPD-1 may play an early role in the pathway of midzone assembly. 相似文献
55.
56.
de Feyter P Mollet N Nieman K Arampatzis A Cademartiri F Pattynama P Serruys P 《Cardiovascular radiation medicine》2004,5(1):49-56
Computed Tomography (Electron Beam Tomography: EBCT and multislice computed tomography: MSCT) have recently emerged as non-invasive diagnostic modalities that can quantify coronary calcium which is not only as indicator of coronary risk, but also permits assessment of the coronary lumen. The 16-slice MS-CT, the most recent CT-scanner has a very high resolution, which allows non-invasive assessment of coronary plaques. This has led to a stimulus for further research to assess the role of MSCT coronary plaque imaging in the identification of high-risk coronary plaques. 相似文献
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58.
Lemmink KA Visscher C Lambert MI Lamberts RP 《Journal of strength and conditioning research / National Strength & Conditioning Association》2004,18(4):821-827
The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to measure intermittent endurance capacity was examined. During the ISRT, participants alternately run for 30 seconds and walk for 15 seconds. The running speed is increased from 10 km.h(-1) every 90 seconds until exhaustion. Within a 2-week period, 17 intermittent sport players (i.e., 10 men and 7 women) performed the ISRT twice in a sports hall under well-standardized conditions. Heart rates per speed and total number of runs were assessed as submaximal and maximal performance measures. With the exception of the heart rates at 10.0 km.h(-1) for men and 10.0, 12.0, and 13.5 km.h(-1) for women, zero lay within the 95% confidence interval of the mean differences, indicating that no bias existed between the outcome measures at the 2 test sessions (absolute reliability). The results illustrate that it is important to control for heart rate before the start of the ISRT. Relative reliability was high (intraclass correlation coefficient > or = 0.86). We conclude that the reliability of the ISRT as a submaximal and maximal field test for intermittent sport players is supported by the results. 相似文献
59.
Lamberts RP Lemmink KA Durandt JJ Lambert MI 《Journal of strength and conditioning research / National Strength & Conditioning Association》2004,18(3):641-645
A change in heart rate at a controlled submaximal exercise intensity is used as a marker of training status. However, the standard error of measurement has not been studied systematically, and therefore a change in heart rate, which can be considered relevant, has not been determined. Forty-four subjects (26.5 +/- 5.4 years; mean +/- standard deviation) participated in a submaximal running test at the same time of day for 5 consecutive days. Heart rates were determined during each of the 4 exercise intensities (2 minutes each) of increasing intensity and during the 1-minute recovery period after each stage. The repeatability of the heart rate on a day-to-day basis during the stages and recovery periods were high (intraclass correlation coefficient: 95% confidence interval R = 0.94- 0.99). The lowest variation in heart rate occurred in the fourth stage ( approximately 90% maximum heart rate) with heart rate varying 5 +/- 2 b.min(-1) (95% confidence interval for coefficient of variation = 1.1-1.4%). In conclusion, the standard error of measurement of submaximal heart rate is 1.1-1.4%. This magnitude of measurement error needs to be considered when heart rate is used as a marker of training status. 相似文献
60.
Cleavage of DNA without loss of genetic information by incorporation of a disaccharide nucleoside 下载免费PDF全文
Nauwelaerts K Vastmans K Froeyen M Kempeneers V Rozenski J Rosemeyer H Van Aerschot A Busson R Lacey JC Efimtseva E Mikhailov S Lescrinier E Herdewijn P 《Nucleic acids research》2003,31(23):6758-6769
A ribose residue inserted between the 3′-OH of one nucleotide and the 5′-phosphate group of the next nucleotide, functions as a site-specific cleavage site within DNA. This extra ribose does not interrupt helix formation and it protects duplex DNA against cleavage by restriction enzymes. Cleavage can be obtained with periodate and all ribose fragments can be removed with sodium hydroxide. As a result of this, an intact natural oligodeoxynucleotide is obtained after ligation reaction, which means that site-specific cleavage and recovering of intact DNA occurs without loss of genetic information. 相似文献