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排序方式: 共有153条查询结果,搜索用时 62 毫秒
11.
Penttilä H Huttunen P von Smitten K Ashammakhi N Waris T 《Plastic and reconstructive surgery》2004,113(7):2057-2060
To investigate the changes in noradrenaline concentrations in transplanted arterial grafts in rats, 31 female rats 4 to 6 weeks old of the AO/Ks:OC strain were operated on. Femoral arterial grafts were anastomosed to carotid arteries and compared with control femoral segments. Six rats were included in each follow-up group at 0, 1, 4, and 12 weeks, and there were seven rats in the 20-week follow-up group. High-performance liquid chromatography was used to determine the concentrations of noradrenaline. The operation itself decreased noradrenaline concentrations in the grafts to 76 percent of that in the control segments. One week after the operation, the noradrenaline concentration had fallen to 1.7 percent of the control values and started to recover thereafter. One month after the operation, it was 23 percent; at 3 months, it was 31 percent; and at 5 months, it was 43 percent of control values. The decrease from time 0 to 1 week was significant (p = 0.001), as was the increase from 1 week to 20 weeks (p = 0.004). Noradrenaline concentrations had fallen significantly 1 week after the operation and thereafter they increased to levels comparable to those seen in the immediate postoperative period. 相似文献
12.
Here, a partial skeleton of Prodeinotherium bavaricum from Unterzolling (Southern Germany) is documented. The following elements are preserved and described for the first time: cervical vertebrae 1-2 and 5-7, the first thoracic vertebra, one lumbar vertebra, trapezium, metacarpals 1-5, tibia, calcaneus, endo- and mesocuneiform, cuboid, the fourth metatarsal, and some phalanges. Comparisons with the skeletons of P. bavaricum from Franzensbad (Czech Republic) and Deinotherium giganteum from Eserovo (Bulgaria) show osteological differences that are described and discussed. 相似文献
13.
The no-on-transient A (nonA) gene encodes a putative RNA-binding protein, and mutations in this gene are known to affect vision, male courtship song and viability in Drosophila melanogaster. Here we have sequenced the coding region of the nonA gene of Drosophila littoralis and compared it with those of Drosophila virilis and D. melanogaster. All portions of nonA appeared to be conserved between D. littoralis and D. virilis, while the 5' region of the gene of these two species showed high divergence from that of a more distantly-related species, D. melanogaster. The same was true for the glycine repeat regions. No significant deviation from neutrality was observed in the analysis of intraspecific nucleotide variation in 5' or 3' region of the nonA gene in D. littoralis population. Also, comparison of D. littoralis sequences with homologous sequence of D. virilis suggests that the gene is evolving neutrally in D. virilis group. Divergence of the 5' regions between D. virilis group species and D. melanogaster could be a result of positive selection, but this finding is obscured by the long divergence time of the species groups. 相似文献
14.
Structural studies of the exopolysaccharide produced by Lactobacillus rhamnosus strain GG (ATCC 53103) 总被引:1,自引:0,他引:1
The structure of the extracellular polysaccharide (EPS) from Lactobacillus rhamnosus strain GG has been investigated. In combination with component analysis, NMR spectroscopy shows that the polysaccharide is composed of hexasaccharide repeating units. Sequential information was obtained by two-dimensional (1)H,(1)H-NOESY, and (1)H,(13)C-HMBC NMR techniques. The structure of the repeating unit of the EPS from Lactobacillus rhamnosus strain GG was determined as: [carbohydrate structure: see text] 相似文献
15.
Fluxes of nitrous oxide and methane from drained peatlands following forest clear-felling in southern Finland 总被引:3,自引:1,他引:2
Jari T. Huttunen Hannu Nykänen Pertti J. Martikainen Mika Nieminen 《Plant and Soil》2003,255(2):457-462
Drainage of waterlogged sites has been part of the normal forestry practice in Fennoscandia, the Baltic countries, the British Isles and in some parts of Russia since the early 20th century, and currently, about 15 million hectares of peatlands and other wetlands have been drained for forestry purposes. The rate of forest clear-felling on drained peatlands will undergo a rapid increase in the near future, when a large number of these forests approach their regeneration age. A small-scale pilot survey was performed at two nutrient-rich and old peatland drainage areas in southern Finland to study if forest clear-felling has significant impacts on the exchange of nitrous oxide (N2O) and methane (CH4) between soil and atmosphere. The average N2O emissions from the two drainage areas during three growing seasons following clear-felling were 945 and 246 g m–2 d–1. The corresponding CH4 fluxes were –0.07 and –0.52 mg m–2 d–1. Clear-felling had impacts on the environmental factors known to affect the N2O and CH4 fluxes of peatlands, i.e. clear-felling raised the water table level and increased the peat temperature. However, no substantial changes in the fluxes of CH4 following clear-felling were observed. The results concerning N2O indicated a potential for increased emissions following clear-felling of drained peatland forests, but further studies are needed for a critical evaluation of the impacts of clear-felling on the fluxes of CH4 and N2O. 相似文献
16.
A viscous extracellular polysaccharide produced by Lactobacillus helveticus Lb161 isolated from raw milk has been investigated. Sugar and methylation analysis, and 1H and 13C NMR spectroscopy revealed that the polysaccharide is composed of a heptasaccharide repeating unit. The sequence of sugar residues was determined by use of two-dimensional nuclear Overhauser effect spectroscopy and heteronuclear multiple bond connectivity experiments. The structure of the repeating unit of the exopolysaccharide from L. helveticus Lb161 is as follows: carbohydrate structure [see text]. The polysaccharide contains approximately 0.6 equivalents of O-acetyl group per repeating unit (not located). 相似文献
17.
Roope J. Huttunen Tomás C. O'Riordan Pirkko L. Härkönen Juhani T. Soini Niko J. Meltola Pekka E. Hänninen Aleksi E. Soini 《Luminescence》2007,22(3):163-170
A method is introduced for quantitative detection of cell surface protein expression. The method is based on immunocytochemistry, the use of long decay time europium(III) chelate and platinum(II) porphyrin labels, and detection of photoluminescence emission from adhered cells by time-resolved fluorimetry. After immunocytochemistry, the assay wells are evaporated to dryness and measured in the dry state. This protocol allows repeated and postponed analysis and microscopy imaging. In order to investigate the performance of the method, we chose expression of intercellular adhesion molecule-1 (ICAM-1) of endothelial cell line EAhy926 as a research target. The expression of ICAM-1 on the cells was enhanced by introduction of a cytokine, tumour necrosis factor-alpha (TNFalpha). The method gave signal:background ratios (S:B) of 20 and 9 for europium and platinum labels, respectively, whereas prompt fluorescent FITC label gave a S:B of 3. Screening window coefficients (=Z'-factor) were >0.5 for all the three labels, thus indicating a score for an excellent screening assay. In conclusion, the method appears to be an appropriate choice for protein expression analysis, both in high-throughput screening applications, and for detailed sample investigation by fluorescent microscopy imaging. 相似文献
18.
Elin Säwén Eine Huttunen Xue Zhang Zhennai Yang Göran Widmalm 《Journal of biomolecular NMR》2010,47(2):125-134
The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in
situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects
of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides
were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT
experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 →, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently
are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two
terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined
using translational diffusion experiments which resulted in Mw = 62 kDa, corresponding to 64 repeating units in the EPS. 相似文献
19.
Do Insectivorous Birds use Volatile Organic Compounds from Plants as Olfactory Foraging Cues? Three Experimental Tests
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Tuuli‐Marjaana Koski Toni Laaksonen Elina Mäntylä Suvi Ruuskanen Tao Li Patricia Sarai Girón‐Calva Liisa Huttunen James D. Blande Jarmo K. Holopainen Tero Klemola 《Ethology : formerly Zeitschrift fur Tierpsychologie》2015,121(12):1131-1144
Some insectivorous birds orient towards insect‐defoliated trees even when they do not see the foliar damage or the herbivores. There are, however, only a few studies that have examined the mechanisms behind this foraging behaviour. Previous studies suggest that birds can use olfactory foraging cues (e.g. volatile organic compounds (VOCs) emitted by defoliated plants), indirect visual cues or a combination of the two sensory cues. VOCs from insect‐defoliated plants are known to attract natural enemies of herbivores, and researchers have hypothesized that VOCs could also act as olfactory foraging cues for birds. We conducted three experiments across a range of spatial scales to test this hypothesis. In each experiment, birds were presented with olfactory cues and their behavioural responses or foraging outcomes were observed. In the first experiment, two different VOC blends, designed to simulate the volatile emissions of mountain birch (Betula pubescens ssp. czerepanovii) after defoliation by autumnal moth (Epirrita autumnata) larvae, were used in behavioural experiments in aviaries with pied flycatchers (Ficedula hypoleuca). The second experiment was a field‐based trial of bird foraging efficiency; the same VOC blends were applied to mountain birches, silver birches (B. pendula) and European white birches (B. pubescens) with plasticine larvae attached to the trees to serve as artificial prey for birds and provide a means to monitor predation rate. In the third experiment, the attractiveness of silver birch saplings defoliated by autumnal moth larvae versus intact controls was tested with great tits (Parus major) and blue tits (Cyanistes caeruleus) in an aviary. Birds did not orient towards either artificial or real trees with VOC supplements or towards herbivore‐damaged saplings when these saplings and undamaged alternatives were hidden from view. These findings do not support the hypothesis that olfactory foraging cues are necessary in the attraction of birds to herbivore‐damaged trees. 相似文献
20.
Kari Taulavuori Henna Pihlajaniemi Satu Huttunen Erja Taulavuori 《Trees - Structure and Function》2011,25(2):231-236
Several deciduous woody plant species produce anthocyanins during leaf development in spring and again during leaf senescence
in autumn. The leaves of Betula pendula Roth (silver birch) commonly exhibit transient reddening in juvenile leaves under northern growing conditions, with the intensity
of the red colour varying among individual trees. The objective of our study was to test the hypothesis that the accumulation
of foliar anthocyanins during spring in leaves of B. pendula is an ecotypic response. Chlorophyll fluorescence ratio (Fv/Fm), leaf reflectance and anthocyanin concentrations were measured,
in relation to phenology in spring, summer and autumn from birches used for landscaping with either red or green-emergent
leaves. The results suggest that (1) the trees with green- or red-emergent juvenile leaves represent different populations,
and (2) that the red-emergent leaves senesced earlier, indicating that (3) trees with red-emerging leaves belong to a more
northern ecotype than the trees with green-emerging leaves. The role of anthocyanin synthesis in a northern radiation environment
is discussed. 相似文献