Differences in the tissue tropism to chicken oviduct epithelial cells between avian coronavirus IBV strains QX and B1648 are not related to the sialic acid binding properties of their spike proteins     

Ann-Kathrin Mork  Martina Hesse  Sahar Abd El Rahman  Silke Rautenschlein  Georg Herrler  Christine Winter 《Veterinary research》2014,45(1):67

The avian coronavirus (AvCoV) infectious bronchitis virus (IBV) is a major poultry pathogen. A characteristic feature of IBV is the occurrence of many different strains belonging to different serotypes, which makes a complete control of the disease by vaccinations a challenging task. Reasons for differences in the tissue tropism and pathogenicity between IBV strains, e.g. a predilection for the kidneys or the oviduct are still an open question. Strains of the QX genotype have been major pathogens in poultry flocks in Asia, Europe and other parts of the world. They are the cause of severe problems with kidney disease and reproductive tract disorders. We analysed infectivity and binding properties of the QX strain and compared them with those of the nephropathogenic strain B1648. As most IBV strains do not infect permanent cell lines and show infection only in primary chicken cells of the target organs, we developed a culture system for chicken oviduct explants. The epithelial cells of the oviduct showed a high susceptibility to infection by the QX strain and were almost resistant to infection by the nephropathogenic B1648 strain. Binding tests with isolated primary oviduct epithelial cells and soluble S1 proteins revealed that S1 proteins of two IBV strains bound with the same efficiency to oviduct epithelial cells. This attachment was sialic acid dependent, indicating that the sugar binding property of IBV spike proteins is not the limiting factor for differences in infection efficiency for the oviduct of the corresponding viruses.  相似文献   

Site-specific formation of Maillard, oxidation, and condensation products from whey proteins during reaction with lactose   总被引：1，自引：0，他引：1  

Meltretter J  Seeber S  Humeny A  Becker CM  Pischetsrieder M 《Journal of agricultural and food chemistry》2007,55(15):6096-6103

Heat treatment of dairy products leads to structural changes of proteins, which can severely decrease the nutritional value [Mauron, J. J. Nutr. Sci. Vitaminol. (Tokyo) 1990, 36 (Suppl. 1), S57-69]. In this study, model solutions of the two main whey proteins, alpha-lactalbumin and beta-lactoglobulin, respectively, were incubated with lactose, and modifications were monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Lactulosyl residues were the most abundant modifications of alpha-lactalbumin and beta-lactoglobulin. Up to four of these adducts were identified on the proteins. Enzymatical digest with endoproteinase AspN prior to mass spectrometric analysis allowed the detection of further modifications and their localization in the amino acid sequence. Most prominent modifications were lactulosyllysine, Nepsilon-carboxymethyllysine, oxidation of lysine to aminoadipic semialdehyde, oxidation of methionine to methionine sulfoxide, cyclization of N-terminal glutamic acid to a pyrrolidone, and oxidation of cysteine or tryptophan. The presence of methionine oxidation was deduced from a control protein that had been oxidized by hydrogen peroxide. These studies establish MALDI-TOF-MS as a reliable tool to monitor chemical modifications of nutritional proteins during food processing.  相似文献   

Inheritance of sesquiterpene lactone types within the Achillea millefolium complex (Compositae)*     

S. Vetter  Ch. Franz  S. Giasl  U. Kastner  J. Saukel  J. Jurenitsch 《Plant Breeding》1997,116(1):79-82

Successful crossing experiments between tetraploid individuals of Achillea ceretanica, A. collina, A. distans ssp. styriaca, and A. pratensis (A. millefolium complex, Compositae) were carried out. Sesquiterpenes of 1013 hybrid plants obtained from 13 crossings were studied by qualitative thin layer chromatography (TLC). F₁-progenies from parent plants with guaianolides (GU-type), as well as the offspring of a back-cross, uniformly contained proazulenes. Diallel crosses between plants exclusively with eudesmanolides (EU-type) resulted in a 7:1 segregation-ratio of EU- and GU-plants. Two reciprocal crossing experiments between EU- and GU-parents resulted in 28.6% and 89.3% EU-individuals, as well as GU-offspring. According to these findings, the qualitative marker ‘proazulene’ (GU-type) is thought to be a recessive character of the tetraploid Achillea species studied.  相似文献   

A gas chromatography/electron ionization-mass spectrometry-selected ion monitoring method for determining the fatty acid pattern in food after formation of fatty acid methyl esters     

Thurnhofer S  Vetter W 《Journal of agricultural and food chemistry》2005,53(23):8896-8903

A method using gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) in the selected ion monitoring (SIM) mode was developed for the analysis of fatty acids as methyl esters (FAMEs) in order to determine their percentage contribution to the fatty acid profile in food. In the GC/EI-MS-SIM mode, saturated fatty acids were determined with m/z 87, monoenoic fatty acids were determined with m/z 74, and polyenoic fatty acids were determined via the sum of m/z 79 and m/z 81. The ratios of these fragment ions and the GC retention data provided additional information for tentative structural assignments. The 28 FAME standards tested provided similar results for the novel GC/EI-MS-SIM method and GC/EI-MS in the full scan mode, both of which were slightly worse than GC/flame ionization detection (FID). Analysis of sunflower oil, suet, and cod liver oil verified that both major and minor fatty acids (20-60% and down to 0.001% contribution to the fatty acid pattern) were determined with sufficient quality that justifies application of the GC/EI-MS-SIM method for the analysis of food samples. Furthermore, the method was approximately 20- or approximately 10-fold more sensitive than GC/EI-MS in the full scan mode or GC/FID, respectively. The method is suited for both quantitative purposes and fatty acid identification in samples where only low amounts of lipids are available.  相似文献   

Limitations of faunal effects on soil carbon flow: density dependence, biotic regulation and mutual inhibition     

Silke Vetter  Oliver Fox  Klemens Ekschmitt  Volkmar Wolters 《Soil biology & biochemistry》2004,36(3):387-397

Soil animals are known to stimulate soil microbial activity and thereby to accelerate decomposition of soil organic matter. In this paper, we investigate potential limitations of soil animal effects on soil carbon flow by analysing how animal effects relate to the density of four major faunal groups. Specifically, we analyse the extent to which faunal effects are subject to biotic regulation or to mutual inhibition between groups under different levels of resource supply.In an extensive laboratory experiment, 96 microcosms established in three consecutive blocks were inoculated with nematodes, enchytraeids, microarthropods, and lumbricids. Each faunal group was inoculated in three densities, including combinations of groups. Introduced animal densities were within the natural range of densities in fallow soil. Bare agricultural soil and soil covered with maize litter were used as substrates. The microcosms were kept under constant conditions at 12 °C and 50% water holding capacity for 8 weeks. Soil CO₂ evolution was measured daily by means of gas chromatography.Animal effects were on an average relatively stronger in bare soil (+95% CO₂; R²=0.76) than in soil with litter (+14% CO₂; R²=0.40), where organic matter decomposition was seven times more intense. Higher animal densities generally led to accelerated decomposition up to three times that of the controls. However, beyond a specific density, decomposition rates stopped increasing or even declined, depending on the faunal group. In addition, animal effects were limited by mutual inhibition between groups in bare soil where effects were strong, while stimulatory interactions were prominent in the litter treatments where effects were generally weak.We interpret the limitation of soil faunal effects on soil carbon flow in terms of incomplete habitat exploitation and biotic regulation. Under conditions of substrate homogeneity, such as in the bare soil treatments, animal effects were stronger, but they were limited by overexploitation. Under conditions of substrate heterogeneity, such as in the litter treatments, animal effects were limited by incomplete habitat utilisation. We assume that complementary habitat colonisation by different faunal groups in the litter treatments gave rise to positive diversity effects, but that these effects did not compensate for reduced overall habitat utilisation. We infer that a knowledge of faunal resource utilisation and of mutual inhibition of faunal groups can be exploited for ecological soil management towards stabilisation of soil organic matter.  相似文献   

Structure of a persistent heptachlorobornane in toxaphene (b7-1000) agrees with molecular model predictions     

Vetter W  Scholz E  Luckas B  Maruya KA 《Journal of agricultural and food chemistry》2001,49(2):759-765

A Cl(7) component of technical toxaphene (CTT), previously detected in marine mammals and fish and referred to as "7-1", was isolated from contaminated estuarine sediment using preparative solid-liquid chromatography followed by reversed-phase HPLC. The structure of this compound, elucidated by GC/MS and (1)H NMR, was 2-endo,3-exo,5-endo,6-exo,8,8,10-heptachlorobornane (hereafter referred to as B7-1000). This newly identified CTT eluted in the nonpolar fraction from silica and shares the alternating endo-exo chlorine substitution pattern with other relatively nonpolar, persistent congeners (e.g., B8-1413 and B9-1679). Based on ECNI-MS response, levels of B7-1000 in tissue samples of various higher organisms including humans were as high as 16% of B8-1413. Enantioselective determination of B7-1000 using a modified cyclodextrin chiral stationary phase (beta-BSCD) resulted in enantiomer ratios that were depleted in adipose tissue of a marine bird (skua) and Weddell seal blubber (0.3 and 0.5, respectively), but not in elephant seal blubber (1.1). Elucidation of the structure of B7-1000 thus validates previous predictions of persistence based on structure-activity relationships, chromatographic properties, and molecular modeling.  相似文献   

Correlation of minimally invasive imaging techniques to assess intestinal mucosal perfusion with established markers of chronic inflammatory enteropathy in dogs     

Mazdak Salavati  Jorge Prez‐Accino  Yi Lin Tan  Tiziana Liuti  Sionagh Smith  Linda Morrison  Silke Salavati Schmitz 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2021,35(1):162-171

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Comparison of cardiopulmonary effects of etorphine and thiafentanil administered as sole agents for immobilization of impala (Aepyceros melampus)     

Silke Pfitzer  Leith Meyer  Liesel Laubscher  Kristin Warren  Rebecca Vaughan-Higgins  Jacobus P. Raath  Michael Laurence 《Veterinary anaesthesia and analgesia》2021,48(1):53-64

ObjectiveTo compare the cardiopulmonary effects of the opioids etorphine and thiafentanil for immobilization of impala.Study designTwo-way crossover, randomized study.AnimalsA group of eight adult female impala.MethodsImpala were given two treatments: 0.09 mg kg^–1 etorphine or 0.09 mg kg^–1 thiafentanil via remote dart injection. Time to recumbency, quality of immobilization and recovery were assessed. Respiratory rate, heart rate (HR), mean arterial blood pressure (MAP) and arterial blood gases were measured. A linear mixed model was used to analyse the effects of treatments, treatments over time and interactions of treatment and time (p < 0.05).ResultsTime to recumbency was significantly faster with thiafentanil (2.0 ± 0.8 minutes) than with etorphine (3.9 ± 1.6 minutes; p = 0.007). Both treatments produced bradypnoea, which was more severe at 5 minutes with thiafentanil (7 ± 4 breaths minute^–1) than with etorphine (13 ± 12 breaths minute^–1; p = 0.004). HR increased with both treatments but significantly decreased over time when etorphine (132 ± 17 to 82 ± 11 beats minute^–1) was compared with thiafentanil (113 ± 22 to 107 ± 36 beats minute^–1; p < 0.001). Both treatments caused hypertension which was more profound with thiafentanil (mean overall MAP = 140 ± 14 mmHg; p < 0.001). Hypoxaemia occurred with both treatments but was greater with thiafentanil [PaO₂ 37 ± 13 mmHg (4.9 kPa)] than with etorphine [45 ± 16 mmHg (6.0 kPa)] 5 minutes after recumbency (p < 0.001). After 30 minutes, PaO₂ increased to 59 ± 10 mmHg (7.9 kPa) with both treatments (p < 0.001).Conclusions and clinical relevanceThe shorter time to recumbency with thiafentanil may allow easier and faster retrieval in the field. However, thiafentanil caused greater hypertension, and ventilatory effects during the first 10 minutes, after administration.  相似文献   

Segmentation of conifer tree crowns from terrestrial laser scanning point clouds in mixed stands of Scots pine and Norway spruce     

Brunner  Andreas  Houtmeyers  Silke 《European Journal of Forest Research》2022,141(5):909-925

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Prevalence and characterization of hypoadrenocorticism in dogs with signs of chronic gastrointestinal disease: A multicenter study     

Christina Hauck  Silke S. Schmitz  Iwan A. Burgener  Astrid Wehner  Reto Neiger  Barbara Kohn  Thomas Rieker  Sven Reese  Stefan Unterer 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(4):1399-1405

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