What can we learn from clubroots: alterations in host roots and hormone homeostasis caused by <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis>   总被引：1，自引：0，他引：1  

Jutta Ludwig-Müller  Astrid Schuller 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(3):291-302

The clubroot disease of cruciferous crops is caused by an obligate biotrophic protist, Plasmodiophora brassicae. The disease is characterized by the development of large root galls accompanied by changes in source-sink relations and the hormonal balance within the plant. Since the disease is difficult to control, it is of high economic interest to understand the events leading to gall formation. In this review we will give an overview on the current knowledge of changes brought about in the host root by this obligate biotrophic pathogen. Emphasis will be on the regulation of changes in plant hormone homeostasis, mainly auxins and cytokinins; the possible role of secondary metabolites, especially indole glucosinolates, in gall formation and auxin homeostasis will be discussed. Also, results from mutant analysis and microarrays using the model plant Arabidopsis thaliana are presented.  相似文献   

Genotypes and phenotypes of an <Emphasis Type="Italic">ex situ</Emphasis><Emphasis Type="Italic">Vitis vinifera</Emphasis> ssp. <Emphasis Type="Italic">sylvestris</Emphasis> (Gmel.) Beger germplasm collection from the Upper Rhine Valley     

Susanne Barth  Astrid Forneck  Fabienne Verzeletti  Rolf Blaich  Fritz Schumann 《Genetic Resources and Crop Evolution》2009,56(8):1171-1181

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Effects of C and N availability and soil-water potential interactions on N₂O evolution and PLFA composition     

Astrid J. Andersen  Søren O. Petersen 《Soil biology & biochemistry》2009,41(8):1726-23

Mitigation of agricultural N₂O emissions via management requires quantitative information about the regulation of the underlying processes. In this laboratory study, short-term evolution of N₂O from repacked soil was determined using an arable sandy loam soil adjusted to three water potentials (−15, −30 or −100 hPa) that were reached by adjustment of partly air-dried soil with nutrient solutions or water; a water retention curve of repacked soil had been determined prior to the incubation experiment. The amendments included a control treatment receiving water (CTL), and aqueous solutions of carbon in the form of glucose (C), ammonium sulfate (N), or both (CN). Rates of CO₂ and N₂O evolution were followed during 14 days. Soil inorganic N and phospholipid fatty acid (PLFA) composition were analyzed by the end of incubation. Across all nutrient treatments, the soil at the lower moisture content (−100 hPa) showed little or no N₂O evolution irrespective of nutrient treatment. Adding glucose alone reduced N₂O evolution relative to CTL. The addition of N alone had no effect on soil respiration, but significantly increased nitrate accumulation and N₂O evolution. The CN treatment resulted in higher respiration than with C amendment alone, but less N₂O evolution than with N alone, at least at −15 and −30 hPa. Whole-soil PLFA fingerprints at the end of incubation reflected the complex response of gaseous emissions. At −15 hPa growth of Gram negative bacteria, probably including denitrifiers, in the CN treatment was indicated by low cyclopropane-to-precursor ratios. At −100 hPa differentiation of branched-chain fatty acids was taken as evidence for an effect of C amendment on Gram positive bacteria. The highest potential for N₂O evolution was observed at the intermediate soil wetness level; the corresponding gas diffusivities indicated that this parameter may be a better predictor of N₂O emissions than water-filled pore space.  相似文献   

In Situ Production of Prebiotic AXOS by Hyperthermophilic Xylanase B from Thermotoga maritima in High‐Quality Bread     

Emmie Dornez  Priscilla Verjans  Willem F. Broekaert  Astrid M. Cappuyns  Jan F. Van Impe  Filip Arnaut  Jan A. Delcour  Christophe M. Courtin 《Cereal Chemistry》2011,88(2):124-129

In situ enrichment of bread with arabinoxylan‐oligosaccharides (AXOS) through enzymic degradation of wheat flour arabinoxylan (AX) by the hyperthermophilic xylanase B from Thermotoga maritima (rXTMB) was studied. The xylanolytic activity of rXTMB during breadmaking was essentially restricted to the baking phase. This prevented problems with dough processability and bread quality that generally are associated with thorough hydrolysis of the flour AX during dough mixing and fermentation. rXTMB action did not affect loaf volume. Bread with a dry matter AXOS content of 1.5% was obtained. Further increase in bread AXOS levels was achieved by combining rXTMB with xylanases from Pseudoalteromonas haloplanktis or Bacillus subtilis. Remarkably, such a combination synergistically increased the specific bread loaf volume. Assuming an average daily consumption of 180 g of fresh bread, the bread AXOS levels suffice to provide a substantial part of the AXOS intake leading to desired physiological effects in humans.  相似文献   

Evaluation of a commercially available human serum amyloid A (SAA) turbidometric immunoassay for determination of equine SAA concentrations     

Jacobsen S  Kjelgaard-Hansen M  Hagbard Petersen H  Jensen AL 《Veterinary journal (London, England : 1997)》2006,172(2):315-319

The aim of the present study was to evaluate whether equine serum amyloid A (SAA) concentrations could be measured reliably with a turbidometric immunoassay (TIA) developed for use with human serum. Intra- and inter-assay imprecision were evaluated by multiple measurements on equine serum pools. Assay inaccuracy was determined by linearity under dilution. The assay was subsequently used for measuring SAA concentrations in clinically healthy horses, horses with inflammatory diseases, horses with non-inflammatory diseases, and in horses before and after castration. In pools with low, intermediate and high SAA concentrations, the intra-assay imprecisions were 24.4%, 1.6% and 2.1%, and the inter-assay imprecisions were 33.2%, 4.6% and 6.5%. Slight signs of inaccuracy were observed, but these inaccuracies were negligible when considering the large dynamic range of the SAA response. The assay was able to detect the expected difference in SAA levels in different groups of horses. It was also able to demonstrate the expected dynamic changes in SAA after castration. In conclusion, equine SAA concentrations can be measured reliably using the TIA designed for human SAA.  相似文献   

Effects of meloxicam on renal function in dogs with hypotension during anaesthesia     

Boström IM  Nyman G  Hoppe A  Lord P 《Veterinary anaesthesia and analgesia》2006,33(1):62-69

OBJECTIVE: To evaluate the effects of meloxicam on renal function in dogs anaesthetized and rendered hypotensive with acepromazine-thiopental-isoflurane. ANIMALS: Eight healthy beagles, four males and four females, 25.6 +/- 19.3 months old and weighing 12.8 +/- 2.0 kg. MATERIALS AND METHODS: Either meloxicam suspension at a dose of 0.133 mL kg(-1) (0.2 mg kg(-1)) or 0.133 mL kg(-1) saline solution (control), were given by mouth (PO) in a randomized, cross-over fashion. The treatment or control was given 3 hours before anaesthesia. Dogs were sedated with intramuscular acepromazine 0.1 mg kg(-1). Anaesthesia was induced with intravenous thiopental, followed by tracheal intubation and maintenance with isoflurane in oxygen and air, delivered using a semi-closed breathing system. Renal function was quantified using serum biochemistry, urinalysis and glomerular filtration rate measured by scintigraphy. Analysis of variance or Friedman anova were used for statistical analysis. RESULTS: Values (mean +/- SD) for mean arterial blood pressure did not differ significantly between treatments but was low (54 +/- 7 mmHg) during anaesthesia. Glomerular filtration rate did not differ significantly between treatments or over time, and results of urine and serum analysis were within reference ranges after meloxicam treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Meloxicam caused no adverse effects on renal function when given to healthy dogs anaesthetized and rendered hypotensive with acepromazine, thiopental and isoflurane.  相似文献   

Changes in Plasma Bradykinin Concentration and Citric Acid Cough Threshold at High Altitude     

Nicholas P. Mason  Merete Petersen  Christian Mélot  Elena V. Kim  Almaz Aldashev  Akpay Sarybaev  Mirsaid M. Mirrakhimov  Robert Naeije 《The Forestry Chronicle》2009,20(4):353-358

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Vegetation competition effects on aboveground biomass and macronutrients,leaf area,and crown structure in 5-year old Douglas-fir     

Kyle S. Petersen  Adrian Ares  Thomas A. Terry  Robert B. Harrison 《New Forests》2008,35(3):299-311

Vegetation control (VC) in forest plantations often increases growth of crop trees but can also affect biomass and nutrient partitioning to tree components. We examined above-ground biomass and macronutrients, leaf area and crown structure in 5-year old Douglas-fir (Pseudotsuga menziessi (Mirb.) Franco) growing with VC and with no vegetation control (NVC) in coastal Washington, United States of America. Trees in VC had larger stem, branch, foliage and total biomass than trees of equal stem diameter at 1.3 m above ground in NVC. The difference in component biomass between treatments was in the order: branch > foliage > stem. Trees in the VC regime did not differ in macronutrient concentration in stem, branch and foliage except for branch N which was greater in NVC than in VC. Differences in tree macronutrient stores between VC and NVC ranged from 2.2 times for Mg to 2.6 times for N and K. The relationship between stem diameter and leaf area was linear in both VC treatments. The relationship between stem diameter and foliage biomass was curvilinear for both VC treatments. Results of this study support the need for separated allometric equations to estimate biomass for young Douglas-fir growing in areas with and without VC.  相似文献   

Crop coefficients for winter wheat in a sub-humid climate regime     

J.H. Kjaersgaard  F. Plauborg  M. Mollerup  C.T. Petersen  S. Hansen 《Agricultural Water Management》2008,95(8):918-924

Estimations of evapotranspiration (ET) from natural surfaces are used in a large number of applications such as agricultural water management and water resources planning. Lack of reliable, cheap and easy-to-use instruments, associated with the chaotic and varying nature of the meteorological and plant physiological factors influencing ET cause these estimations to be based on calculated values rather than the measured ones. The two-step approach where ET from a reference crop is calculated and multiplied by empirical crop coefficients to obtain ET from a crop has gained wide acceptance. Daily coefficients for a winter wheat crop growing under standard conditions, i.e. not short of water and growing under optimal agronomic conditions, were estimated for a cold sub-humid climate regime. One of the two methods used to estimate ET from a reference crop required net radiation (R_n) as input. Two sets of coefficients were used for calculating R_n. Weather data from a meteorological station was used to estimate R_n and ET from the reference crop. The winter wheat ET was measured using an eddy covariance system during the main parts of the growing seasons 2004 and 2005. The meteorological data and field measurements were quality controlled and discarded from the analysis if flagged for errors. Daily values of ET from the reference crop and winter wheat calculated from hourly values were used to calculate the crop coefficients. Average daily crop coefficients were in the 1.1–1.15 range during mid-season with standard deviations ranging from 0.13 to 0.23 for both years. These values exceed values used in some sub-humid climate regime studies, but agree well with values from the international literature.  相似文献   

Molecular markers linked to the <Emphasis Type="Italic">fin</Emphasis> gene controlling determinate growth habit in common bean   总被引：1，自引：1，他引：0  

Astrid Pañeda  Cristina Rodríguez-Suárez  Ana Campa  Juan José Ferreira  Ramón Giraldez 《Euphytica》2008,160(2):241-248

The S-genotypes of 16 apricot (Prunus armeniaca L.) cultivars native to China were determined by the S-allele PCR approach and the results were confirmed by cross-pollination tests among these cultivars. Primer combination EM-PC2consFD + EM-PC3consR, based on the conserved regions C2 and C3 of Rosaceous S-RNase genes, was the most useful primer combination for identifying Chinese apricot S-alleles. Twelve S-RNase alleles were identified using this primer combination, and they were defined as follows: S ₉ was 657 bp, S ₁₀ was 266 bp, S ₁₁ was 464 bp, S ₁₂ was 360 bp, S ₁₃ was 401 bp, S ₁₄ was 492 bp, S ₁₅ was 469 bp, S ₁₆ was 481 bp, S ₁₇ was 487 bp, S ₁₈ was 1337 bp, S ₁₉ was 546 bp and S ₂₀ was 1934 bp. S ₁₁–S ₂₀ were new S-RNase genes deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively. Our findings contribute to a more efficient breeding program of Chinese apricot and further studies on the S-RNase genes.  相似文献