Foot-and-mouth disease virus: a first inter-laboratory comparison trial to evaluate virus isolation and RT-PCR detection methods     

Ferris NP  King DP  Reid SM  Hutchings GH  Shaw AE  Paton DJ  Goris N  Haas B  Hoffmann B  Brocchi E  Bugnetti M  Dekker A  De Clercq K 《Veterinary microbiology》2006,117(2-4):130-140

Five European reference laboratories participated in an exercise to evaluate the sensitivity and specificity of their routinely employed RT-PCR tests and cell cultures for the detection and isolation of foot-and-mouth disease (FMD) virus. Five identical sets of 20 coded samples were prepared from 10 vesicular epithelia, which were derived from submissions from suspect cases of FMD or swine vesicular disease (SVD). Sixteen samples were derived from six FMD virus positive epithelia representing four different serotypes (two each of types O and A and one each of types Asia 1 and SAT 2), two from samples which had been found to be negative by antigen ELISA and virus isolation (VI) in cell culture and two from SVD virus positive epithelia. Some of the FMD virus positive samples were prepared from 10-fold serial dilutions of three of the initial suspensions. Each laboratory tested the samples by one or more of its available RT-PCR procedures and inoculated cell cultures that it routinely uses for FMD diagnosis in attempts to isolate virus, the specificity of which was confirmed by antigen ELISA. The best of the RT-PCR assays used in each laboratory gave comparable results while the sensitivity of cell cultures was variable from high in one laboratory, moderate in two and low in two others. This prototype panel of samples would appear suitable for external quality assurance of these tests but would benefit from the inclusion of more negative samples and an extension in the serial dilution range of one or more of the FMD positive sample titration series.  相似文献   

Mammary health: breeding     

de Haas Y  de Jong G  Lam TJ 《Tijdschrift voor diergeneeskunde》2008,133(11):464-468

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The Purple Cross aid for wounded and sick Army horses     

Haas KB 《Veterinary heritage : bulletin of the American Veterinary History Society》1997,20(2):37-39

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Dynamics of post‐harvest pathogens Neofabraea spp. and Cadophora spp. in plant residues in Dutch apple and pear orchards          下载免费PDF全文

J. Köhl  M. Wenneker  B. H. Groenenboom‐de Haas  R. Anbergen  H. M. Goossen‐van de Geijn  C. H. Lombaers‐van der Plas  F. A. M. F. Pinto  P. Kastelein 《Plant pathology》2018,67(6):1264-1277

Post‐harvest diseases of apple and pear cause significant losses. Neofabraea spp. and Cadophora spp. infect fruits during the growing season and remain quiescent until disease symptoms occur after several months in storage. Epidemiological knowledge of these diseases is limited. TaqMan PCR assays were developed for quantification of N. alba, N. perennans, C. malorum and C. luteo‐olivacea in environmental samples. Various host tissues, dead weeds and grasses, soil and applied composts were collected in 10 apple and 10 pear orchards in May 2012. Neofabraea alba was detected in 73% of samples from apple orchards and 48% from pear orchards. Neofabraea perennans was present in a few samples. Cadophora luteo‐olivacea was detected in 99% of samples from apple orchards and 93% from pear orchards, whilst C. malorum was not detected in any sample. In apple orchards, highest concentrations of N. alba were found in apple leaf litter, cankers and mummies, and of C. luteo‐olivacea in apple leaf litter, mummies and dead weeds. In pear orchards, N. alba and C. luteo‐olivacea were found in highest concentrations in pear leaf litter and in dead weeds. Substrate colonization varied considerably between orchards. The temporal dynamics of pathogens was followed in four apple orchards and four pear orchards. In apple orchards the colonization by pathogens decreased from April until August and increased from September until December. This pattern was less pronounced in pear. Knowledge on population dynamics is essential for the development of preventative measures to reduce risks of fruit infections during the growing season.  相似文献   

Development and evaluation of Taqman assays for the differentiation of Dickeya (sub)species     

J. M. van der Wolf  B. H. de Haas  R. van Hoof  E. G. de Haan  G. W. van den Bovenkamp 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(4):695-709

TaqMan assays were developed for the detection of seven Dickeya species, namely D. dianthicola, D. dadantii, D. paradisiaca, D. chrysanthemi, D. zeae, D. dieffenbachiae and D. solani. Sequences of the gene coding for dnaX were used for the design of primers and probes. In studies with axenic cultures of bacteria, the assays were highly specific and only reacted with strains of the target species, and not with non-target bacteria, including those belonging to other Dickeya species and other genera. The detection thresholds for DNA extracted from pure cultures of target strains ranged from 10 to 100 fg. The TaqMan assays for D. dianthicola and D. solani were more extensively evaluated as part of a method validation procedure. The threshold level for target bacteria added to a potato peel extract diluted ten-times in a semi-selective broth, was strain dependent and ranged from 1,000 to 100,000 cfu/ml. The coefficients of variation for repeatability and reproducibility were low and results were largely independent of the type of substrate, i.e. potato tuber or carnation leaf extracts. However, during routine testing of seed potatoes, false-positive reactions were found with the assay for D. solani. The use of the TaqMan assays for inspection of plant propagation material, ecological studies and studies on the effect of control strategies in disease management strategies is discussed.  相似文献   

Obituary James (חיים, Jimmy) Krikun     

Jerry H. Haas  Leah Tsror  Jaacov Katan 《Phytoparasitica》2014,42(2):293-294

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C型肉毒梭菌肉毒毒素的提取与鉴定     

薛正坤  吴伟  张晶  李超毅  吴辉  李莲瑞 《新疆农业科学》2013,50(3):557

[目的]通过对C型肉毒梭菌肉毒毒素的提取与鉴定,为类毒素和抗毒素的制备及抗原性分析奠定基础.[方法]将分离鉴定得到的C型肉毒梭菌通过扩大培养、产毒培养后将产生的肉毒毒素采用除菌过滤、硫酸铵盐盐析、离心、透析、浓缩的方法从产毒培养基中分离提取出来.再将提取的肉毒毒素通过SDS-PAGE鉴定毒素蛋白的分子量.[结果]分离出来的毒素蛋白重链和轻链分别在98和53 KDa左右,与C型肉毒毒素的理论分子量相符.[结论]提取的肉毒毒素是C型肉毒毒素.  相似文献   

Epidemiology of dark leaf spot caused by Alternaria brassicicola and A. brassicae in organic seed production of cauliflower     

J. Köhl  C. A. M. Van Tongeren  B. H. Groenenboom‐de Haas  R. A. Van Hoof  R. Driessen  L. Van Der Heijden 《Plant pathology》2010,59(2):358-367

In organic seed production of Brassica vegetables, infections by Alternaria brassicicola and A. brassicae can cause severe losses of yield and seed quality. Four field experiments with or without artificial inoculation with A. brassicicola were conducted in organically managed seed‐production crops of cauliflower cv. Opaal RZ in 2005 and 2006 in the Netherlands. The development of A. brassicicola and A. brassicae on pod tissues and developing seeds was followed and seed quality was assessed. Alternaria brassicicola was externally present on 1·2% of the seeds 14 days after flowering and observed internally within 4 weeks after flowering. In both seasons, seed colonization by the pathogen increased slowly until maturation but sharply increased during maturation. A similar pattern was found for the colonization of pod tissues by A. brassicicola as quantified by TaqMan‐PCR. The incidence of A. brassicicola on mature seeds reached 70–90%. Internal colonization was found for 62–80% of the seeds. External and internal seed colonization by A. brassicae was much lower, with incidences below 3%. The quality of harvested seeds was generally low, with less than 80% of seeds able to germinate. Seed quality was not affected by warm water treatments. It was concluded that A. brassicicola and A. brassicae have the potential to infect pods and seeds soon after flowering. For the production of high quality seeds, producers must prevent such early infections. Therefore, new control measures are needed for use in organic cropping systems.  相似文献   

Esophageal foreign body in a 2-day-old calf     

Jackie Haas 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(4):406-408

A 2-day-old male Charolais crossbred calf presented with a section of an esophageal feeding tube partially obstructing his esophagus. External palpation of the neck confirmed the location of the obstruction to be within the cervical esophagus. A rumenotomy was performed and the foreign body was successfully removed.  相似文献   

Molecular identification of a 16SrIII-B phytoplasma associated with cassava witches’ broom disease     

Daniela Flôres  Isolda Cristina Haas  Maria Cristina Canale  Ivan Paulo Bedendo 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(2):237-242

Since its arrival in the British Isles in 1845 Phytophthora infestans has remained the most destructive pathogen of potato. In the ensuing period, the British and Irish P. infestans populations have undergone major displacements following the immigration of novel strains. Here we report the re-emergence of the Ib mitochondrial DNA haplotype in the British and Irish P. infestans populations associated with the 6_A1 genotype. Historically associated with the previously panglobally distributed clonal lineage US-1, the Ib haplotype has not been detected (with the exception of a single isolate in the mid 1990s) in the British or Irish P. infestans populations since the early 1980s. The 6_A1 isolates analysed possessed mtDNA Ib, but were otherwise quite unlike US-1, having the Pep allozyme genotype 96/96 and novel RG57 and SSR fingerprints. These genetic characteristics strongly suggest that the appearance of the 6_A1 genotype in these populations has resulted from migration (possibly after a recombination event elsewhere). This study highlights the advantages of utilising a range of different markers in pathogen monitoring.  相似文献