Diversity,spatial variation,and temporal dynamics of virulences in the German leaf rust (<Emphasis Type="Italic">Puccinia recondita</Emphasis> f. sp. <Emphasis Type="Italic">secalis</Emphasis>) population in winter rye     

Thomas Miedaner  Bettina Klocke  Kerstin Flath  Hartwig H. Geiger  W. Eberhard Weber 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):23-35

A large collection of German rye leaf rust isolates was analysed to characterize the diversity, spatial variation and temporal dynamics of virulences. Virulence-avirulence phenotypes (=pathotypes) were determined on 23 host differentials. We found 93 pathotypes among 177 single-uredinial isolates in 2000, 201 pathotypes among 437 isolates in 2001, and 125 pathotypes among 213 isolates in 2002. In total, the 827 analyzed isolates represented 317 pathotypes. Frequency of virulences on the individual differentials varied from 2% to 97%. Eight of the differentials showed a high resistance level with virulence frequencies <10%. Virulence complexity of the isolates ranged from 3 to 21 with a mean of nine. The percentages of highly virulent isolates (>14 virulences) increased from 4 to 15% during the sampling period. A high level of virulence diversity was observed within and between individual sampling sites with Simpson indices around 0.9. Evenness indices ranged from 0.88 to 0.92. Four of the five most frequent pathotypes were found in each year but their frequency never exceeded 10%. Isolates with unusual virulence combinations could be clearly separated by principal component analysis. Location-specific pathotype frequencies were revealed in each year, but the frequency patterns varied across years. On four fields a considerable increase of highly virulent pathotypes occurred within 6 weeks during the epidemic. The high diversity of pathotypes as well as the fast accumulation of highly virulent pathotypes favour the adaptation of the pathogen to race-specific host resistances. More durable resistance might be achievable by combining new effective race-specific resistances with adult-plant and/or race-non-specific quantitative resistances.  相似文献   

Use of fatty acid profiles to identify food-borne bacterial pathogens and aerobic endospore-forming bacilli     

Whittaker P  Fry FS  Curtis SK  Al-Khaldi SF  Mossoba MM  Yurawecz MP  Dunkel VC 《Journal of agricultural and food chemistry》2005,53(9):3735-3742

Capillary gas chromatography (GC) with flame ionization detection was used to determine the cellular fatty acid profiles of various food-borne microbial pathogens and to compare the fatty acid profiles of spores and vegetative cells of the same endospore-forming bacilli. Fifteen bacteria, representing eight genera (Staphylococcus, Listeria, Bacillus, Yersinia, Salmonella, Shigella, Escherichia, and Vibrio) and 11 species were used to compare the extracted fatty acid methyl esters (FAMEs). Endospore-forming bacilli were processed to obtain pure spores and whole cell FAMEs for GC analysis. A data set for each bacterial agent was prepared using fatty acid profiles from five replicates prepared on different days. The results showed that these fatty acid intensity profiles were unique for each of the 11 species and that they could be used as a fingerprint for the organisms. The cellular fatty acid profiles for Bacillus anthracis and Bacillus cereus show that there are two branched chain fatty acids, iso 17:1 omega10c and 17:1 anteiso, which are unique in these species. Iso 17:1 omega10c is present in B. cereus vegetative cells and spores but is not observed in B. anthracis. The 17:1 anteiso fatty acid is present in B. anthracis cells but not in B. cereus cells. Fatty acids 16:0 2OH and 17:0 iso 3OH are present in B. anthracis and B. cereus spores but not in the vegetative cells. In summary, analysis of FAMEs from bacteria and spores can provide a sensitive procedure for the identification of food-borne pathogens.  相似文献   

Model‐based evaluation of agri‐environmental measures in the Federal State of Brandenburg (Germany) concerning N pollution of groundwater and surface water     

Kurt Christian Kersebaum  Bettina Matzdorf  Joachim Kiesel  Annette Piorr  Jrg Steidl 《植物养料与土壤学杂志》2006,169(3):352-359

GIS‐based modeling of soil‐crop interactions and hydrological processes is a valuable instrument to assess land‐use effects on N pollution of water resources from the agricultural sector. A case study is presented using spatial information on soils, climatic zones, land use, and distribution of agri‐environmental measures within the federal State of Brandenburg (Germany) to assess the reduction effect of EU‐funded measures on N pollution of water resources. In a first step, the area was classified concerning the risk for groundwater and surface‐water pollution. For this, spatially distributed model calculations of the soil‐solution exchange frequency were intersected to a vulnerability map for groundwater derived from geological data and zones of different transit times from the root zone into surface waters. In a second step, model calculations of water and N dynamics in the soil‐crop system for different crop and management systems were performed to calculate nitrate leaching from the root zone and to estimate the effect of present agri‐environmental measures to reduce N pollution on groundwater and surface waters. The results indicated that 75% of the agri‐environmental measures were placed in areas with low impact on groundwater and surface waters. Therefore, the effectiveness of the agri‐environmental measures concerning water‐protection aims was moderate.  相似文献   

Intact carbohydrate structures as part of the melanoidin skeleton   总被引：6，自引：0，他引：6  

Cämmerer B  Jalyschko W  Kroh LW 《Journal of agricultural and food chemistry》2002,50(7):2083-2087

Model melanoidins from monomeric, oligomeric, and polymeric carbohydrates, and amino acids formed under aqueous as well as water-free reaction conditions, were submitted to acidic catalyzed hydrolysis. Their degradation products were detected qualitatively and quantitatively by HPTLC and HPLC-DAD. A considerable amount of monomer carbohydrates from hydrolysis of model melanoidins formed under water-free reaction conditions was detected. It can be seen clearly that the amount of carbohydrates released increased with increasing degree of polymerization of the carbohydrates used as starting material. In comparison, the hydrolysis of melanoidins formed in aqueous condition resulted in only a small glucose release. It seems that in the Maillard reaction under water-free conditions, a significant amount of di- and oligomer carbohydrates were incorporated into the melanoidin skeleton as complete oligomer with intact glycosidic bond, forming side chains at the melanoidin skeleton. Additional side chains could be formed by transglycosylation reactions. With increasing water content, hydrothermolytic as well as retro-aldol reactions of the starting carbonyl components became significant, and therefore the possibility of forming side chains decreased. The results are consistent with the postulated melanoidin structure being built up mainly from sugar degradation products, probably branched via amino compounds.  相似文献   

Helicobacter pylori vacuolating cytotoxin inhibits T lymphocyte activation     

Gebert B  Fischer W  Weiss E  Hoffmann R  Haas R 《Science (New York, N.Y.)》2003,301(5636):1099-1102

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Evaluation of immune responses following infection of ponies with an EHV-1 ORF1/2 deletion mutant     

Soboll Hussey G  Hussey SB  Wagner B  Horohov DW  Van de Walle GR  Osterrieder N  Goehring LS  Rao S  Lunn DP 《Veterinary research》2011,42(1):23

ABSTRACT: Equine herpesvirus-1 (EHV-1) infection remains a significant problem despite the widespread use of vaccines. The inability to generate a protective immune response to EHV-1 vaccination or infection is thought to be due to immunomodulatory properties of the virus, and the ORF1 and ORF2 gene products have been hypothesized as potential candidates with immunoregulatory properties. A pony infection study was performed to define immune responses to EHV-1, and to determine if an EHV-1 ORF1/2 deletion mutant (ΔORF1/2) would have different disease and immunoregulatory effects compared to wild type EHV-1 (WT). Infection with either virus led to cytokine responses that coincided with the course of clinical disease, particularly the biphasic pyrexia, which correlates with respiratory disease and viremia, respectively. Similarly, both viruses caused suppression of proliferative T-cell responses on day 7 post infection (pi). The ΔORF1/ORF2 virus caused significantly shorter primary pyrexia and significantly reduced nasal shedding, and an attenuated decrease in PBMC IL-8 as well as increased Tbet responses compared to WT-infected ponies. In conclusion, our findings are (i) that infection of ponies with EHV-1 leads to modulation of immune responses, which are correlated with disease pathogenesis, and (ii) that the ORF1/2 genes are of importance for disease outcome and modulation of cytokine responses.  相似文献   

Intraocular nematodiasis in a llama (Lama glama)     

Dunkel B  Sweeney RW  Habecker PL  Komaromy AM 《The Canadian veterinary journal. La revue veterinaire canadienne》2011,52(2):181-183

This report describes a unique case of presumed migration of Parelaphastrongylus tenuis through the spinal cord into the eye of a llama where it survived and matured within the ocular environment. Blindness of the eye was most likely attributable to migration of the parasite through the central nervous tissue.  相似文献   

Evaluation of otoacoustic emissions in clinically normal alert puppies     

Schemera B  Blumsack JT  Cellino AF  Quiller TD  Hess BA  Rynders PE 《American journal of veterinary research》2011,72(3):295-301

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Molecular biology of Porcine circovirus: analyses of gene expression and viral replication   总被引：21，自引：0，他引：21  

Mankertz A  Caliskan R  Hattermann K  Hillenbrand B  Kurzendoerfer P  Mueller B  Schmitt C  Steinfeldt T  Finsterbusch T 《Veterinary microbiology》2004,98(2):81-88

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Influence of insecticidal plant materials used during storage on sensory attributes and instrumental hardness of dry edible beans (Phaseolus vulgaris L.)     

Florence V. Dunkel  Assumani Serugendo  William M. Breene  Shobha Sriharan 《Plant foods for human nutrition (Dordrecht, Netherlands)》1995,48(1):1-16

Three plant products with known insecticidal properties, a dry extract of flowers ofChrysanthemum cinerariaefolium (Trevir.) Vis. produced in Rwanda, an ethanol extract of seeds of neem,Azadirachta indica A. Juss., and crushed leaves ofTetradenia riparia Hochst Codd., a traditional Rwandan medicine, were mixed with beans,Phaseolus vulgaris L., for storage protection. These plant-protected beans were compared with off the shelf beans that were being sold to consumers by the Rwandan National Agricultural Products Marketing Organization (OPROVIA). A trained sensory panel determined that beans treated with neem andC. cinerariaefolium were as acceptable after 8 months storage as those being sold throughout Rwanda by the marketing organization. Beans marketed by this organization were all treated with the standard insecticide application in Rwanda, 0.01% weight/weight pirimiphos methyl in a powder formulation. Instrumental hardness (% hard-to-cook/mean gram force) after 20 months of storage was acceptable for beans stored with neem or withC. cinerariaefolium or with the conventional government application of pirimiphos methyl. Use of either neem orC. cinerariaefolium for storage protection should not affect consumer acceptance of dry beans.  相似文献