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101.
Genes and enzymes involved in caffeic acid biosynthesis in the actinomycete Saccharothrix espanaensis 下载免费PDF全文
Berner M Krug D Bihlmaier C Vente A Müller R Bechthold A 《Journal of bacteriology》2006,188(7):2666-2673
The saccharomicins A and B, produced by the actinomycete Saccharothrix espanaensis, are oligosaccharide antibiotics. They consist of 17 monosaccharide units and the unique aglycon N-(m,p-dihydroxycinnamoyl)taurine. To investigate candidate genes responsible for the formation of trans-m,p-dihydroxycinnamic acid (caffeic acid) as part of the saccharomicin aglycon, gene expression experiments were carried out in Streptomyces fradiae XKS. It is shown that the biosynthetic pathway for trans-caffeic acid proceeds from L-tyrosine via trans-p-coumaric acid directly to trans-caffeic acid, since heterologous expression of sam8, encoding a tyrosine ammonia-lyase, led to the production of trans-p-hydroxycinnamic acid (coumaric acid), and coexpression of sam8 and sam5, the latter encoding a 4-coumarate 3-hydroxylase, led to the production of trans-m,p-dihydroxycinnamic acid. This is not in accordance with the general phenylpropanoid pathway in plants, where trans-p-coumaric acid is first activated before the 3-hydroxylation of its ring takes place. 相似文献
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A.-S. Pirson K. Van Laere J. George J. Jamart B. Krug Y. D’Asseler S. Minoshima T. Vander Borght 《Médecine Nucléaire》2009,33(10):625-631
Fully automated analysis programs have been applied more and more to aid for the reading of regional cerebral blood flow SPECT study. They are increasingly based on the comparison of the patient study with a normal database. In this study, we evaluate the ability of Three-Dimensional Stereotactic Surface Projection (3D-SSP) to isolate effects of age and gender in a previously studied normal population. The results were also compared with those obtained using Statistical Parametric Mapping (SPM99).MethodsEighty-nine 99mTc-ECD-SPECT studies performed in carefully screened healthy volunteers (46 females, 43 males; age 20–81 years) were analysed using 3D-SSP. A multivariate analysis based on the general linear model was performed with regions as intrasubject factor, gender as intersubject factor and age as covariate.ResultsBoth age and gender had a significant interaction effect with regional tracer uptake. An age-related decline (p < 0.001) was found in the anterior cingulate gyrus, left frontal association cortex and left insula. Bilateral occipital association and left primary visual cortical uptake showed a significant relative increase with age (p < 0.001). Concerning the gender effect, women showed higher uptake (p < 0.01) in the parietal and right sensorimotor cortices. An age by gender interaction (p < 0.01) was only found in the left medial frontal cortex. The results were consistent with those obtained with SPM99.Conclusion3D-SSP analysis of normal rCBF variability is consistent with the literature and other automated voxel-based techniques, which highlight the effects of both age and gender. 相似文献
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Fernanda Bernardes Calvo Dário Santos Junior Consuelo Junqueira Rodrigues Francisco José Krug Júlio Takehiro Marumo Nestor Schor Maria Helena Bellini 《Biological trace element research》2009,130(2):107-113
The development of cancer is a complex, multistage process during which a normal cell undergoes genetic changes that result
in phenotypic alterations and in the acquisition of the ability to invade other sites. Inductively coupled plasma optical
emission spectroscopy was used to estimate the contents of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, and Zn in healthy
kidney and renal cell carcinoma (RCC), and significant differences were found for all elements. Along with the progression
of the malignant disease, a progressive decrease of Cd and K was observed. In fact, for Cd, the concentration in stage T4
was 263.9 times lower than in stage T1, and for K, the concentration in stage T4 was 1.73 times lower than in stage T1. Progressive
accumulation was detected for P, Pb, and Zn in stage T4. For P, the concentration in stage T4 was 11.1 times higher than in
stage T1; for Pb, the concentration in stage T4 was 232.7 times higher than in T1; and for Zn, the concentration in T4 was
8.452 times higher than in T1. This study highlights the marked differences in the concentrations of selected trace metals
in different malignant tumor stages. These findings indicate that some trace metals may play important roles in the pathogenesis
of RCC. 相似文献
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Angus Burnett Peter O’Sullivan Joao Paulo Caneiro Roberto Krug Frank Bochmann Gry Wang Helgestad 《Journal of electromyography and kinesiology》2009,19(4):e229-e236
The flexion-relaxation phenomenon (FRP) is well documented at end-range lumbar spine flexion in both standing and sitting however, the FRP has been insufficiently investigated in cervico-thoracic musculature. The aim of this study was to determine whether the FRP occurs during forward flexion of the neck, in lumbo-pelvic sitting, amongst a pain-free population. Surface electromyography (EMG) was used to measure muscle activation in 20 (10 men, 10 women) asymptomatic subjects in selected cervico-thoracic muscles during four, 5-s phases (upright posture, forward flexion, full flexion and return to upright) while subjects were positioned in lumbo-pelvic sitting. Spinal kinematics were simultaneously measured using an electromagnetic motion tracking device. No FRP was observed in upper trapezius or thoracic erector spinae (T4). When using visual methods to determine the presence/absence of the FRP, five subjects were believed to show evidence of the FRP in the cervical erector spinae. However, when using various non-visual criteria to determine the existence of the FRP, substantial variations (0–13 subjects) were evident. We recommend that criteria based upon relatively large differences in muscle activation should be considered when defining the FRP. These findings are of significance for future investigations examining specific cervical pain disorders. 相似文献
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Goddert von Oheimb Sally A. Power Kirsten Falk Uta Friedrich Abdelmenam Mohamed Angelika Krug Nora Boschatzke Werner Härdtle 《Ecosystems》2010,13(2):317-327
There is growing evidence from different sources that prolonged high N deposition causes a shift from nitrogen (N) limitation
to nitrogen and phosphorus (P) co-limitation or even P limitation in many terrestrial ecosystems. However, the number of ecosystems
where the type of limitation has been directly tested by longer-term full-factorial field experiments is very limited. We
conducted a 5-year fertilization experiment with N and P in the Lüneburger Heide (NW Germany) to test the hypothesis that,
following decades of elevated atmospheric N inputs, plant growth in dry lowland heaths may have shifted from N to N–P co-limitation
or P limitation. We also tested whether the plant tissue N:P ratio reflects the type of nutrient limitation in a continental
lowland heathland. Experimental plots dominated by Calluna vulgaris received regular additions of N (50 kg N ha−1 y−1), P (20 kg P ha−1 y−1), a combination of both, or water only (control) from 2004 to 2008. Over the whole study period, a highly significant positive
N effect on shoot length was found, thus indicating N limitation. We conclude that a clear shift from N limitation to N–P
co-limitation or P limitation has not yet occurred. Tissue N:P ratios showed a high temporal variability and no relationship
between tissue N:P ratio and the shoot length response of Calluna to nutrient addition was found. The N:P tool is thus of limited use at the local scale and within the range of N:P ratio
observed in this study, and should only be used as a rough indicator for the prediction of the type of nutrient limitation
in lowland heathland on a larger geographical scale with a broader interval of N:P ratio. 相似文献
110.
Gursinsky T Ruhs S Friess U Diabaté S Krug HF Silber RE Simm A 《Biological chemistry》2006,387(10-11):1411-1420
Air pollution is associated with a variety of respiratory and cardiovascular disorders, including fibrosis. To understand the possible molecular mechanisms underlying this observation, we examined the effect of particulate matter on primary fibroblasts, the key regulators of the extracellular matrix. Fly ash collected in an experimental waste incinerator was used as model particles for fine and ultrafine pollution components. Brief treatment of fibroblasts isolated from adult male Wistar rat hearts with fly ash triggered the immediate formation of intracellular reactive oxygen species (ROS). Using phospho-specific antibodies we observed activation of p38 MAP kinase, p44/42 MAP kinase (ERK1/2) and p70(S6) kinase. Prolonged incubation with fly ash increased the expression of collagen 1 and TGF-beta1, but decreased mRNA levels of MMP9 and TNF-alpha. Cell proliferation was inhibited at high concentrations of fly ash. An increase in the level of advanced glycation endproduct (AGE) modification of various cellular proteins after long-term treatment of cultured fibroblasts with fly ash was observed. The results of our study demonstrate that direct activation of fibroblasts by combustion-derived particles is a mechanism that may contribute to the adverse health effects of particulate air pollution. 相似文献