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Reaction Type (reaction + type)
Selected AbstractsRhizoctonia solani AG 2-1 as a causative agent of cotyledon rot on European beech (Fagus sylvatica)FOREST PATHOLOGY, Issue 6 2005A. M. Hietala Summary Rhizoctonia solani was frequently isolated in the Italian Alps from nursery-grown European beech (Fagus sylvatica) seedlings displaying symptoms of cotyledon rot. Koch's postulates were verified and mode of infection of the associated isolates was investigated with light and scanning electron microscopy. Population structure of the pathogen was investigated by scoring the anastomosis reaction type in pairings between different isolates from the same seedbed. One pathogen genotype showed a large distribution area within the seedbed, this implying that the inoculum had been building up in the seedbed over a longer time period. Hyphal anastomosis tests and sequence analysis of the internal transcribed spacer (ITS) region of ribosomal DNA indicated that the pathogen belongs to AG 2-1 of R. solani. ITS sequence analysis indicates that the isolates from beech are closely related to R. solani isolates causing a disease on tulip. The striking similarities between the two diseases are discussed. Résumé Rhizoctonia solani a fréquemment été isolé de semis de hêtre (Fagus sylvatica) présentant des symptômes de pourriture des cotylédons dans une pépinière forestière des Alpes italiennes. Les postulats de Koch ont été vérifiés et le mode d'infection étudié par microscopie optique et électronique à balayage. La structure de la population de l'agent pathogène a étéétudiée en examinant les réactions d'anastomoses dans les confrontations par paires des isolats d'un même lit de semences. Un génotype particulier s'est avéré largement distribué dans le lit de semence, suggérant soit une accumulation de l'inoculum pendant une longue période soit que ce génotype est capable de reproduction homocaryotique, favorisant sa dispersion. Les tests d'anastomose et l'analyse de la séquence de la région ITS de l'ADN ribosomal indiquent que l'agent pathogène appartient au groupe AG 2-1 de R. solani. L'analyse de la séquence de l'ITS montre que les isolats de hêtre sont proches d'isolats de R. solani pathogènes sur tulipe. Les ressemblances frappantes entre les deux maladies et la gestion de la maladie sur hêtre sont discutées. Zusammenfassung In einer Forstbaumschule in den italienischen Alpen wurde Rhizoctonia solani häufig aus Buchenkeimlingen (Fagus sylvatica) mit Symptomen einer Kotyledonenfäule isoliert. Die Koch'schen Postulate wurden erfüllt und die Art der Infektion der beteiligten Isolate wurde licht- und rasterelektronen-mikroskopisch untersucht. Die Populationsstruktur des Pathogens wurde anhand der Reaktionstypen (Anastomosierungsverhalten) in Paarungsversuchen mit den unterschiedlichen Isolaten aus demselben Saatbeet untersucht. Ein Kompatibilitätstyp war innerhalb des Saatbeetes weit verbreitet, was darauf hindeutet, dass sich das Inokulum über einen längeren Zeitraum dort angereichert hatte und/oder der Genotyp homokaryotisch fruchtet, was seine Ausbreitung fördert. Die Anastomosierungstests und die ITS-Sequenzanalyse der ribosomalen DNA ergaben, dass der Erreger zu der AG 2-1 Gruppe R. solani gehört. Die ITS-Sequenzen deuten darauf hin, dass die Isolate von Buche mit den R. solani, Isolaten verwandt sind, die an Tulpen pathogen sind. Die auffallende Ähnlichkeit der beiden Krankheiten und das Management der Erkrankung an Buche wird diskutiert. [source] Powdery Mildew Resistance in Barley Landraces from MoroccoJOURNAL OF PHYTOPATHOLOGY, Issue 5 2000J. H. Czembor Nineteen barley landraces collected from Morocco were screened for resistance to powdery mildew. The landraces originated from the collection at the Polish Gene Bank, IHAR Radzików, Poland. The fifteen landraces tested showed powdery mildew resistance reactions and 35 single plant lines were selected. Twenty-one of these lines were tested in the seedling stage with 30, four lines with 17 and another 10 lines with 23 differential isolates of powdery mildew, respectively. The isolates were chosen according to their virulence spectra observed on the Pallas isolines differential set. Nine lines (E 1029-1-1, E 1042-2-2, E 1050-1-1, E 1054-5-1, E 1056-2-5, E 1056-3-1, E 1061-1-1, E 1061-1-3 and E 1067-1-2) which originated from seven landraces showed resistance to all prevalent European powdery mildew virulence genes. The most frequent score was 2 and 16 lines showed this reaction for inoculation with most isolates used. The distribution of reaction type indicated that about 77% of all reaction types observed were classified as powdery mildew resistance (scores 0, 1 and 2). In all lines the presence of unknown genes alone or in combinations with specific ones was postulated. Four different resistance alleles (Mlat, Mla6, Mla14 and Mla12) were postulated to be present in 10 tested lines alone or in combination. Alleles Mlat, Mla6 and Mla14 were postulated to be present in four and Mla12 in two tested lines, respectively. The value of barley landraces for diversification of resistance genes for powdery mildew is discussed. Zusammenfassung Neunzehn Gerstenlandrassen aus Marokko wurden auf ihre Resistenz gegenüber dem Echten Mehltau untersucht. Diese Landrassen wurden in der Sammlung der Polish Gene Bank, IHAR, Radzikow, Polen aufbewahrt. Fünfzehn der geprüften Rassen zeigten Echte Mehltau-Resistenz und davon wurden 35 einzelne Pflanzenlinien selektiert. 21 dieser Linien wurden als Sämlinge gegenüber 30, 4 Linien gegenüber 17 und weitere 10 Linien gegenüber 23 differentialen Echten Mehltau-Isolaten geprüft. Diese Isolate wurden an Hand von ihren Virulenzspektren bei dem Pallas-Isoline-Differential-Set ausgewählt. Bei 9 Linien (E 1029-1-1, E 1042-2-2, E 1050-1-1, E 1054-5-1,E1056-2-5, E 10456-3-1, E 1061-1, E 1061-1-3 sowie E 1067-1-2), die von 7 Landrassen stammten, konnte eine Resistenz gegenüber allen bedeutenden europäischen Virulenzgenen festgestellt werden. Am häufigsten wurde die Resistenznote 2 vergeben, 16 Linien zeigten diese Reaktion nach einer Inokulation mit den meisten angewandten Isolaten. Die Verteilung des Reaktionstyps deutete daraufhin, dass ca. 77% der beobachteten Reaktionstypen als Echte Mehltau-Resistenz (die Note 0,1 und 2) eingestuft werden konnten. Das Vorkommen von unbekannten Genen, ob alleine oder in Kombination mit einem spezifischen Gen, wurde in allen Linien postuliert. Ebenfalls postuliert wurde das Vorhandensein von vier unterschiedlichen Resistenzallelen (Mlat, Mla6, Mla14 und Mla12), entweder alleine oder in Kombinationen, in den 10 geprüften Linien. Die Allele Mlat, Mla6 und Mla14 wurden in 4, das Allel Mla12 in 2 der getesteten Linien postuliert. Die Relevanz von Landrassen in der Erweiterung von Resitenzgenen gegenüber dem Echten Mehltau in der Gerste wird diskutiert. [source] Inhibition of the development of leaf rust (Puccinia recondita) by treatment of wheat with allopurinol and production of a hypersensitive-like reaction in a compatible hostPLANT PATHOLOGY, Issue 3 2000A. L. Ádám The effect of allopurinol [4-hydroxypyrazolo (3,4- d) pyrimidine], a purine analogue inhibitor of xanthine oxidase (XO) enzyme, was studied in the host,pathogen combination of Triticum aestivum,Puccinia recondita f.sp. tritici. Analysis of purines and pyrimidines in the allopurinol-treated wheat seedlings showed marked accumulation of xanthine, suggesting the inplanta inhibition of XO activity. In the incompatible wheat,rust interaction application of allopurinol as a drench, even at the highest concentration (50 ,m), did not change the hypersensitive reaction phenotype; only the number of lesions was slightly reduced. Allopurinol treatment decreased the augmented rate of electrolyte leakage and lipid peroxidation associated with the hypersensitive response (HR), an effect probably related to the inhibition of rust development by allopurinol. By contrast, in the case of the compatible wheat,leaf-rust combination the reaction type was strongly affected. The formation of uredia and production of uredospores were diminished or completely inhibited depending on the concentration of allopurinol, which was applied either as a drench (3.125,50 ,m) or as a foliar spray (100,400 ,m) to plants grown in perlite. At the highest allopurinol concentration in the drench, the compatible reaction type changed to a hypersensitive-like necrotic reaction. Significant increases in electrolyte leakage and lipid peroxidation (characteristic of the HR) were found 4,6 days after infection in susceptible plants treated with allopurinol. Staining of leaf slices from allopurinol-treated and compatible rust-infected plants with Evans blue indicated cell death surrounding the pustules, while at this stage no cell death was detected in infected leaves without allopurinol treatment. The above results suggest that XO is not the main source of the generation of active oxygen species in wheat during the HR to leaf rust. [source] A two-phase model for variable-density fluidized bed reactors with generalized nonlinear kineticsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2000Zahra M. Tafreshi Abstract A model based on the classical two-phase concept is developed for the simulation of variable-density reaction with generalized nonlinear kinetics in a bubbling fluidized bed. The influence of reaction density parameter on the fluidodynamics and performance of the reactor for four general types of reactions was explored. The results show that the expansion factor has a significant effect on both fluidodynamic characteristics and reaction conversion. In all types of reactions, higher values of hydro-dynamic variables were obtained when , , 0. Reaction conversion, however, dropped as the expansion factor increased. This trend was more pronounced for reaction orders higher than unity. This suggests that bubbling fluidized operations are probably not optimal and applicable for certain types of reactions. Comparative analysis between reaction type and implications for optimum fluidized bed reactor are discussed. On a mis au point un modèle basé sur le concept classique à deux phases pour la simulation de la réaction à densité variable avec les cinétiques non linéaires généralisées dans un lit fluidisé bouillonnant. L'influence du paramètre de densité de réaction sur la dynamique des fluides et la performance du réacteur a été étudiée pour quatre types généraux de réaction. Les résultats montrent que le facteur d'expansion a un effet significatif sur les caractéristiques de dynamique des fluides et la conversion de la réaction. Dans tous les types de réactions, de grandes valeurs de variables hydrodynamiques ont été obtenues pour , , 0. Cependant, la conversion de la réaction chute lorsque le facteur d'expansion augmente. Cette tendance est plus prononcée pour des ordres de réaction supérieurs à l'unite. Cela suppose que les opérations en lit fluidisé bouillonnant ne sont probablement pas optimales ni applicables à certains types de réaction. L'analyse comparative entre le type de réaction et les implications pour un réacteur à lit fluidisé bouillonnant est examinée. [source] Contact allergy to foodDERMATOLOGIC THERAPY, Issue 4 2004Ronald R. Brancaccio ABSTRACT:, Contact allergies to foods, spices, and food additives can occur to individuals in the workplace or at home. Seven different reaction types have been described. These include irritant contact dermatitis, allergic contact dermatitis, contact urticaria, protein contact dermatitis, phototoxic contact dermatitis, photo-allergic contact dermatitis, and systemic contact dermatitis. The causes of each of these are reviewed and an approach to the diagnosis and management of contact allergy to foods, spices, and food additives is formulated. [source] Powdery Mildew Resistance in Barley Landraces from MoroccoJOURNAL OF PHYTOPATHOLOGY, Issue 5 2000J. H. Czembor Nineteen barley landraces collected from Morocco were screened for resistance to powdery mildew. The landraces originated from the collection at the Polish Gene Bank, IHAR Radzików, Poland. The fifteen landraces tested showed powdery mildew resistance reactions and 35 single plant lines were selected. Twenty-one of these lines were tested in the seedling stage with 30, four lines with 17 and another 10 lines with 23 differential isolates of powdery mildew, respectively. The isolates were chosen according to their virulence spectra observed on the Pallas isolines differential set. Nine lines (E 1029-1-1, E 1042-2-2, E 1050-1-1, E 1054-5-1, E 1056-2-5, E 1056-3-1, E 1061-1-1, E 1061-1-3 and E 1067-1-2) which originated from seven landraces showed resistance to all prevalent European powdery mildew virulence genes. The most frequent score was 2 and 16 lines showed this reaction for inoculation with most isolates used. The distribution of reaction type indicated that about 77% of all reaction types observed were classified as powdery mildew resistance (scores 0, 1 and 2). In all lines the presence of unknown genes alone or in combinations with specific ones was postulated. Four different resistance alleles (Mlat, Mla6, Mla14 and Mla12) were postulated to be present in 10 tested lines alone or in combination. Alleles Mlat, Mla6 and Mla14 were postulated to be present in four and Mla12 in two tested lines, respectively. The value of barley landraces for diversification of resistance genes for powdery mildew is discussed. Zusammenfassung Neunzehn Gerstenlandrassen aus Marokko wurden auf ihre Resistenz gegenüber dem Echten Mehltau untersucht. Diese Landrassen wurden in der Sammlung der Polish Gene Bank, IHAR, Radzikow, Polen aufbewahrt. Fünfzehn der geprüften Rassen zeigten Echte Mehltau-Resistenz und davon wurden 35 einzelne Pflanzenlinien selektiert. 21 dieser Linien wurden als Sämlinge gegenüber 30, 4 Linien gegenüber 17 und weitere 10 Linien gegenüber 23 differentialen Echten Mehltau-Isolaten geprüft. Diese Isolate wurden an Hand von ihren Virulenzspektren bei dem Pallas-Isoline-Differential-Set ausgewählt. Bei 9 Linien (E 1029-1-1, E 1042-2-2, E 1050-1-1, E 1054-5-1,E1056-2-5, E 10456-3-1, E 1061-1, E 1061-1-3 sowie E 1067-1-2), die von 7 Landrassen stammten, konnte eine Resistenz gegenüber allen bedeutenden europäischen Virulenzgenen festgestellt werden. Am häufigsten wurde die Resistenznote 2 vergeben, 16 Linien zeigten diese Reaktion nach einer Inokulation mit den meisten angewandten Isolaten. Die Verteilung des Reaktionstyps deutete daraufhin, dass ca. 77% der beobachteten Reaktionstypen als Echte Mehltau-Resistenz (die Note 0,1 und 2) eingestuft werden konnten. Das Vorkommen von unbekannten Genen, ob alleine oder in Kombination mit einem spezifischen Gen, wurde in allen Linien postuliert. Ebenfalls postuliert wurde das Vorhandensein von vier unterschiedlichen Resistenzallelen (Mlat, Mla6, Mla14 und Mla12), entweder alleine oder in Kombinationen, in den 10 geprüften Linien. Die Allele Mlat, Mla6 und Mla14 wurden in 4, das Allel Mla12 in 2 der getesteten Linien postuliert. Die Relevanz von Landrassen in der Erweiterung von Resitenzgenen gegenüber dem Echten Mehltau in der Gerste wird diskutiert. [source] Tissue reaction of the rabbit urinary bladder to tension-free vaginal tape and porcine small intestinal submucosaBJU INTERNATIONAL, Issue 6 2002D.M. Rabah Objectives ,To compare the histological tissue reactions of urinary bladder in close contact with polypropylene mesh tension-free vaginal tape (TVT) or porcine small intestinal submucosal (SIS) grafts, as the commercial availability of various materials has considerably simplified sling procedures for treating urinary incontinence, but erosion and infection after using artificial sling materials remain an important concern. Materials and methods ,Thirty female New Zealand rabbits were randomized to three groups, i.e. group A (TVT, 12 animals), group B (SIS, 12) and group C (surgical control, six). Through a laparotomy under anaesthesia and an aseptic technique, the bladder was approached at its dome, where a 0.5 × 1 cm piece of TVT or SIS was fixed in direct contact with the bladder wall. The control group underwent only bladder manipulation with no material applied. Half the animals in each group were killed after 6 weeks and the other half after 12 weeks. The urinary bladder was harvested and examined histologically. Results ,The grafts in both groups were characterized by dense foreign-body type reactions and were mostly attached loosely to the bladder wall by a thin layer of fibrovascular tissue. More importantly, the bladder wall reactions showed no inflammation in all 12 animals in group A (TVT) but three of them had various grades of fibrosis. There was severe transmural inflammation in one animal in group B (SIS); one rabbit had grade I and two had grade II fibrosis. The controls, as expected, showed no bladder wall reactions. Conclusion ,In this descriptive analysis of reaction types elicited on the urinary bladder by these grafts, both materials appeared to be safe. Although TVT elicited fewer and less severe adverse reactions, no statistical conclusions can be drawn. The clinical significance of these findings should emerge from long-term clinical data when they become available. [source] | |||||||||||||