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排序方式: 共有556条查询结果,搜索用时 46 毫秒
1.
Henk-jan Schoonbeek Johannes G.M. van Nistelrooy Maarten A. de Waard 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(9):1003-1011
The role of multiple ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporter genes from the plant pathogenic fungus Botrytis cinerea in protection against natural fungitoxic compounds was studied by expression analysis and phenotyping of gene-replacement mutants. The expression of 11 ABC (BcatrA–BcatrK) and three MFS genes (Bcmfs1, Bcmfs2 and Bcmfs4) was studied. All genes showed a low basal level of expression, but were differentially induced by treatment with cycloheximide and the plant defence compounds camptothecin, eugenol, psoralen, resveratrol and rishitin. The latter compounds induced expression of BcatrB at a high level. Eugenol was more toxic to BcatrB gene-replacement mutants than to the control isolates. Eugenol also caused an instantaneous increase in mycelial accumulation of the fungicide fludioxonil, a known substrate of BcatrB. However, there was no difference in virulence between the wild-type and BcatrB gene-replacement mutants on Ocimum basilicum, a plant known to contain eugenol. The results indicate that BcatrB is a transporter of lipophilic compounds, such as eugenol, but its role in virulence remains uncertain. 相似文献
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Johannes Papajoannou 《Forstwissenschaftliches Centralblatt》1934,56(23):769-782
Ohne ZusammenfassungHerr Professor Fabricius hat mir das Versuchsgelände, Herr Professor Schmausz, als Vorstand des Forstmeteorologischen Institutes, die Meszgeräte in liebenswürdiger Weise zur Verfügung gestellt. Herr Professor Geiger und Herr Regierungsforstrat Woelfle haben mich miederholt mit Rat und Hilfe unterstübt. Jhnen allen spreche ich zum Schlusz meinen besten Dank aus. 相似文献
4.
Junfeng Wang Yujie Shi Yunna Ao Dafu Yu Jiao Wang Song Gao Johannes M. H. Knops Chunsheng Mu Zhijian Li 《Journal of Agronomy and Crop Science》2019,205(6):554-561
Extreme drought events can directly decrease productivity in perennial grasslands. However, for rhizomatous perennial grasses it remains unknown how drought events influence the belowground bud bank which determines future productivity. Ninety‐day‐long drought events imposed on Leymus chinensis, a rhizomatous perennial grass, caused a 41% decrease in the aboveground biomass and a 28% decrease in belowground biomass. Aboveground biomass decreased due to decrease in both the parent and the daughter shoot biomass. The decreases in daughter shoot biomass were due to reductions in both the shoot number and each individual shoot weight. Most importantly, drought decreased the bud bank density by 56%. In addition, drought induced a bud allocation change that decreased by 41% the proportion of buds that developed into shoots and a 41% increase in the buds that developed into rhizomes. Above results were supported by our field experiment with watering treatments. Thus, a 90‐day‐long summer drought event decreases not only current productivity but also future productivity, because the drought reduces the absolute bud number. However, plasticity in plant development does partly compensate for this reduction in bud number by increasing bud development into rhizomes, which increases the relative allocation of buds into future shoots, at the cost of a decrease in current shoots. 相似文献
5.
Margaret L. Musser Austin K. Viall Rachel L. Phillips Jesse M. Hostetter Chad M. Johannes 《Canadian journal of veterinary research》2021,85(1):68
In many human cancers, the expression of the prostaglandin receptor EP4 (EP4R) is associated with the development of malignancy and a poor prognosis. The expression of EP4R has not yet been evaluated in canine tumors. The objective of this study was to characterize the messenger RNA (mRNA) expression of EP4R in canine osteosarcoma (OSA). Gene expression of EP4R was evaluated using RNA in-situ hybridization (RNAscope). In all canine OSA samples evaluated, strong universal positive expression of EP4R was identified. Gene expression was significantly higher in OSA tissue samples than in normal nasal turbinate bone, possibly implicating EP4R in the pathogenesis of canine OSA. 相似文献
6.
Thomas R. De Ridder Justine E. Campbell Cheryl Burke‐Schwarz David Clegg Emily L. Elliot Samuel Geller Wendy Kozak Stephen T. Pittenger Jennifer B. Pruitt Jocelyn Riehl Julie White Melissa L. Wiest Chad M. Johannes John Morton Pamela D. Jones Peter F. Schmidt Victoria Gordon Paul Reddell 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2021,35(1):415-429
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Hampel V Schwarz B Kempf C Köstlin R Schillinger U Küchenhoff H Fenske N Brill T Hirschberger J 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(6):1340-1346
BACKGROUND: Recombinant feline interferon-omega (rFeIFN-omega) was tested as a treatment option for cats with fibrosarcoma to assess safety and feasibility. HYPOTHESIS: Treatment with rFeIFN-omega in cats with fibrosarcoma is safe and feasible. ANIMALS: Twenty domestic cats. METHODS: In an open-labeled uncontrolled clinical trial 12 injections of 1 x 10(6) U/kg rFeIFN-omega were administered over a 5-week period: the 1st through 4th injections were given intratumorally, and the 5th through 12th injections were administered subcutaneously at the tumor excision site. Wide surgical excision of the tumors was carried out after the 4th injection and before the 5th injection of rFeIFN-omega. A Common Terminology Criteria for Adverse Events (CTCAE) analysis was conducted. Flow cytometry of fibrosarcoma cells after incubation with rFeIFN-omega and recombinant feline interferon-gamma was performed to assess the biological effect of rFeIFN-omega. RESULTS: Changes in blood cell count, increases in serum aspartate-amino-transferase activity, serum bilirubin concentration, serum creatinine and serum electrolyte concentrations, weight loss, anorexia, increased body temperature, and reduced general condition were observed but were mostly minor (grade 1 and 2) and self limiting. Eosinophilia (P = .025), neutropenia (P = .021), and weight loss (P < .001) were statistically correlated with rFeIFN-omega-treatment (analysis of parameters before treatment and after 3 injections of rFeIFN-omega). Flow cytometry of 5 unrelated feline fibrosarcoma cell lines showed increased expression of major histocompatibility complex (MHC) class I molecules (P = .026) in response to in vitro incubation with rFeIFN-omega, whereas expression of MHC class II molecules was not affected significantly. CONCLUSIONS AND CLINICAL IMPORTANCE: RFeIFN-omega for the treatment of feline fibrosarcoma is safe, well tolerated, and can be easily performed in practice. To assess the efficacy of the treatment, it should be tested in a placebo-controlled trial. 相似文献
9.
Johannes Makadho 《Irrigation and Drainage Systems》1996,10(4):367-376
Timing of supply of irrigation water is an important measure of water management performance. Yet despite this widely accepted importance of timeliness, few studies have attempted to quantify this performance indicator. This paper suggests a methodology for quantifying timeliness. The indices thus generated are used to compare the performance of some types of smallholder irrigation schemes in Zimbabwe. Results indicate that applying measures of timeliness helps to assess water management practices across scheme types.The methodology given in this paper differentiates between timely irrigation deliveries which meet Crop Water Requirements (CWR) and surplus water supplies due to poor timeliness which cannot be used by the crop, hence denoting wastage. The timeliness indices provide more information regarding management practices than simple measures of total water applications over a given season. 相似文献
10.
In low-intensity grazing systems, patch grazing leads to a mosaic structure of short (frequently defoliated) and tall (rarely defoliated) patches, with the stocking rate determining the proportion of these patch types on the pasture. Little is known about the long-term effects of patch grazing on the productivity of contrasting sward height patches developed under varying stocking rates. On a 12-year low-intensity cattle pasture we investigated aboveground net primary productivity (ANPP) and its seasonal variation in different patch types (‘short’, ‘medium’ and ‘tall’) under three stocking rates (‘moderate’, ‘lenient’ and ‘very lenient’) over two years. Additionally, we determined stocks of soil phosphorus, potassium and magnesium as well as soil pH. ANPP was affected by an interaction of patch type and stocking rate and ranged from less than 300 g/m2 in short patches under very lenient stocking to more than 1,000 g/m2 in medium patches under moderate stocking. In contrast with observations at the start of the experiment, ANPP in short patches was similar to or less than that in medium and tall patches. As topsoil phosphorus and potassium stocks were lowest in short patches, this indicates a long-term redistribution of nutrients by grazing animals, which limits short-patch productivity. Productivity of medium patches increased with stocking rate, and soil potassium concentration showed a similar trend, pointing towards enhanced nutrient cycling under more intensive stocking. We conclude that nutrient redistribution may lead to increasing trade-offs between ecological and agronomic aims in long-term low-intensity grazing systems. 相似文献