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91.
Hüttner K Seelmann M Feldhusen F 《Berliner und Münchener tier?rztliche Wochenschrift》2010,123(11-12):463-467
Despite indications of a considerable spread of Maedi-Visna among sheep flocks in Germany, prevalence studies of this important infection are hardly available. Prior to any health schemes and guidelines, knowledge about regional disease distribution is essential. Depending upon herd size, 70 farms were randomly selected, of which 41 cooperated. A total of 2229 blood samples were taken at random and serologically examined. For assessment of selected farm characteristics a questionnaire exercise was conducted at all farms involved. The average herd prevalence is 51.2%, the within-herd prevalence is 28,8%. In the unvariate analysis of risk factors, small (10-100 sheep) and large (> 250 sheep) farms are more MVV-affected than medium sized farms. The average stable and pasture space per sheep is larger at non-infected- compared to infected farms. Owners judgement on general herd health turns out to be better at non-infected compared to infected farms. Taking infected farms only, the risk of within-herd prevalence above 20% is significant higher in crossbred than in purebred flocks. 相似文献
92.
Herman W. Favoreel Céline Van den BroekeAnn Desplanques Matthias DeruelleGeert Van Minnebruggen Hans NauwynckSarah Glorieux Nina Van OpdenboschNick De Regge 《Veterinary microbiology》2010
Two major structural elements of a cell are the cytoskeleton and the lipid membranes. Actin and cholesterol are key components of the cytoskeleton and membranes, respectively, and are involved in a plethora of different cellular processes. This review summarizes and discusses the interaction of alphaherpesviruses with actin and cholesterol during different stages of the replication cycle: virus entry, replication and assembly in the nucleus, and virus egress. Elucidating these interactions not only yields novel insights into the biology of these important pathogens, but may also shed new light on cell biological aspects of actin and cholesterol, and lead to novel avenues in the design of antiviral strategies. 相似文献
93.
Sawa S Cherrier M Lochner M Satoh-Takayama N Fehling HJ Langa F Di Santo JP Eberl G 《Science (New York, N.Y.)》2010,330(6004):665-669
Lymphoid tissue-inducer (LTi) cells initiate the development of lymphoid tissues through the activation of local stromal cells in a process similar to inflammation. LTi cells express the nuclear hormone receptor RORγt, which also directs the expression of the proinflammatory cytokine interleukin-17 in T cells. We show here that LTi cells are part of a larger family of proinflammatory RORγt(+) innate lymphoid cells (ILCs) that differentiate from distinct fetal liver RORγt(+) precursors. The fate of RORγt(+) ILCs is determined by mouse age, and after birth, favors the generation of cells involved in intestinal homeostasis and defense. Contrary to RORγt(+) T cells, however, RORγt(+) ILCs develop in the absence of microbiota. Our study indicates that RORγt(+) ILCs evolve to preempt intestinal colonization by microbial symbionts. 相似文献
94.
Galaxy clusters form through a sequence of mergers of smaller galaxy clusters and groups. Models of diffusive shock acceleration suggest that in shocks that occur during cluster mergers, particles are accelerated to relativistic energies, similar to conditions within supernova remnants. In the presence of magnetic fields, these particles emit synchrotron radiation and may form so-called radio relics. We detected a radio relic that displays highly aligned magnetic fields, a strong spectral index gradient, and a narrow relic width, giving a measure of the magnetic field in an unexplored site of the universe. Our observations show that diffusive shock acceleration also operates on scales much larger than in supernova remnants and that shocks in galaxy clusters are capable of producing extremely energetic cosmic rays. 相似文献
95.
Characterization and quantitation of low and high molecular weight phenolic compounds in apple seeds
Fromm M Bayha S Carle R Kammerer DR 《Journal of agricultural and food chemistry》2012,60(5):1232-1242
The phenolic constituents of seeds of 12 different apple cultivars were fractionated by sequential extraction with aqueous acetone (30:70, v/v) and ethyl acetate after hexane extraction of the lipids. Low molecular weight phenolic compounds were individually quantitated by RP-HPLC-DAD. The contents of extractable and nonextractable procyanidins were determined by applying RP-HPLC following thiolysis and n-butanol/HCl hydrolysis, respectively. As expected, the results revealed marked differences of the ethyl acetate extracts, aqueous acetone extracts, and insoluble residues with regard to contents and mean degrees of polymerization of procyanidins. Total phenolic contents in the defatted apple seed residues ranged between 18.4 and 99.8 mg/g. Phloridzin was the most abundant phenolic compound, representing 79-92% of monomeric polyphenols. Yields of phenolic compounds significantly differed among the cultivars under study, with seeds of cider apples generally being richer in phloridzin and catechins than seeds of dessert apple cultivars. This is the first study presenting comprehensive data on the contents of phenolic compounds in apple seeds comprising extractable and nonextractable procyanidins. Furthermore, the present work points out a strategy for the sustainable and complete exploitation of apple seeds as valuable agro-industrial byproducts, in particular as a rich source of phloridzin and antioxidant flavanols. 相似文献
96.
Nitrogen is a major nutrient that frequently limits primary productivity in terrestrial ecosystems. Therefore, the physiological responses of plants to soil nitrogen (N) availability have been extensively investigated, and the study of the soil N-cycle has become an important component of ecosystem ecology and biogeochemistry. The bulk of the literature in these areas has, however, overlooked the fact that most plants form mycorrhizal associations, and that nutrient uptake is therefore mediated by mycorrhizal fungi. It is well established that ecto- and ericoid mycorrhizas influence N nutrition of plants, but roles of arbuscular mycorrhizas in N nutrition are less well established; perhaps even more importantly, current conceptual models ignore possible influences of arbuscular mycorrhizal (AM) fungi on N-cycling processes. We review evidence for the interaction between the AM symbiosis with microbes and processes involved in soil N-cycling. We show that to date investigations have rather poorly addressed such interactions and discuss possible reasons for this. We outline mechanisms that could potentially operate with regards to AM fungal – N-cycling interactions, discuss experimental designs aimed at studying these, and conclude by pointing out priorities for future research. 相似文献
97.
Matthias Vanmaercke Willem Maetens Jean Poesen Benediktas Jankauskas Genovaite Jankauskiene Gert Verstraeten Joris de Vente 《Journal of Soils and Sediments》2012,12(4):586-602
Purpose
This study aims to understand better the relationship between measured soil loss rates due to sheet and rill erosion (SL), predicted SL rates and measured catchment sediment yields (SY) in Europe. 相似文献98.
Jaine H. H. L. de Oliveira Mirna H. R. Seleghim Christoph Timm Achim Grube Matthias K?ck Gislene G.F. Nascimento Ana Claudia T. Martins Elissa G. O. Silva Ana Olívia de Souza Paulo R. R. Minarini Fabio C. S. Galetti Célio L. Silva Eduardo Hajdu Roberto G. S. Berlinck 《Marine drugs》2006,4(1):1-8
Cyclostellettamines A – F (1 – 6) isolated from the sponge Pachychalina sp. and cyclostellettamines G - I, K and L (7 – 11) obtained by synthesis were evaluated in bioassays of antimicrobial activity against susceptible and antibiotic-resistant Staphylococcus aureus, Pseudomonas aeruginosa and antibiotic-susceptible Escherichia coli and Candida albicans, as well as in antimycobacterial activity against Mycobacterium tuberculosis H37Rv bioassays. The results obtained indicated that cyclostellettamines display different antimicrobial activity depending on the alkyl-chain size, suggesting that, if a mechanism-of action is implied, it is dependent on the distance between the two pyridinium moieties of cyclostellettamines. 相似文献
99.
ABSTRACT: Single nucleotide polymorphisms (SNPs) in the genes for interleukin-4, -13 and interferon-gamma, and 21 additional SNPs which previously had been significantly associated with immune traits in the chicken, were genotyped in white and brown layer hens and analyzed for their association with helminth burden following natural infections. A nucleotide substitution located upstream of the promoter of the interferon-gamma gene was significantly associated with the log transformed number of Ascaridia galli in the brown layer line (genotype CC: 6.4 ± 1.0 worms; genotype CT: 11.7 ± 2.2 worms). Therefore, IFNG seems to be a promising candidate gene for further studies on helminth resistance in the chicken. 相似文献
100.
Völkel I Schmitz C Moors E Gauly M Czerny CP 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(1-2):71-77
During the fattening period of a broiler flock four different litter materials (peat, chopped straw, shavings, silage) were tested simultaneously.The separated sections were tested for the presence of Salmonella bacteria using the sock-sampling method as described in the regulation EC No. 646/2007 with slight modifications in the sampling technique and the laboratory protocol. In addition, some chemical and physical parameters regarding litter quality and house climate were analysed. Samples were taken at day 0 (housing of animals), day 14, and day 30. At the end of the fattening period Salmonella Paratyphi B (d-tartrate +), representing a common strain in German broiler flocks, were isolated from culture. According to the various types of bedding materials some differences in the frequency of Salmonella detection were found. With three samples out of six samples being positive, wood shavings showed the highest Salmonella prevalence, followed by peat with two positive results. Corn silage was found to be a suitable alternative for common litter materials and revealed only one positive sample. Chopped straw was found to be free of Salmonella in our study. However, the latter had a higher risk for negative side effects concerning animal health and house climate. The study showed that the choice of an appropriate litter material might be of considerable importance in order to decrease the Salmonella burden within poultry flocks. 相似文献