Summary Incorporation of Virazole into potato explant and meristem culture media results in a higher percentage of virus-free progeny
plants from virus-infected explant and meristem donor plants than are produced in tissue cultures in the absence of Virazole.
Viruses eliminated, singly and as complexes, include potato viruses X, Y, S and M.
The need for sensitive virus tests to distinguish between virus suppression and elimination is discussed and protein-A-linked
immunoelectron microscopy is described and quantified for potato virus X.
Zusammenfassung In der vorliegenden und einer früheren Arbeit (Cassells & Long, 1980) zeigte Kultivierung von Explantaten auf einem Medium
für Gewebekultur mit Virazole (Ribavirin) einen signifikanten Anstieg virusfreier Adventivschosse gegenüber der Kontrolle.
Diese Adventivschosse wie auch Kartoffelpflanzen zweiter Generation verhielten sich auch gegenüber den empfindlichsten immunoelektronen-mikroskopischen
Tests virusfrei.
In Gegenwart von Virazol ergab auch Meristemkultur einen h?heren Anteil virusfreier Pflanzen als bei Fehlen dieser Verbindung.
Die Kartoffelviren X, Y, M und S sowie Viruskomplexe konnten aus den Sorten May Queen, King Edward, Kerr's Pink und Golden
Wonder eliminiert werden (Tabellen 2 und 3).
Die Ergebnisse der Anwendung und der Quantifizierung der Protein A-gebundenen Immuno-Elektronenmikroskopie (PALIEM) werden
ebenfalls dargestellt (Abb. 1).
Résumé Cette étude a montré, comme d'autres travaux préliminaires (Cassels & Long, 1980), que le fait de cultiver des boutures sur
un milieu de culture de tissus contenant du virazole (ribavirine) permettait d'augmenter de fa?on significative le nombre
de tiges aventices indemmes de virus par rapport au témoin. Ces tiges adventices, dans le cas de plants de deuxième génération,
sont apparues indemmes de virus par l'analyse des tests les plus sensibles de microscopie immuno-électronique.
En présence du virazole, la culture de méristèmes montre également un taux plus élevé de plants indemmes de virus que sans
l'application de virazole.
Les virus concernés sont les virus X, Y, M, S ainsi, que les complexes viraux, provenant des variétés May Queen, King Edward,
Kerr's Pink et Golden Wonder (tableau 2 et 3).
Sont également indiqués les résultats qualificatifs et quantitatifs de la microcopie immunoélectronique avec utilisation de
la protéine A (PALIEM) (figure 1).
Gastrointestinal segments from 4 healthy, 17-, 21-, 22- and 23-day-old calves fed on whole cow’s milk were examined. Scanning electron microscopy showed that the anterior duodenum had short villi varying in shape from leaf-shaped to nodular; the middle duodenum had broad, tongue-shaped villi and the anterior, middle, and parts of the posterior jejunum had slender, finger-shaped or leaf-shaped villi. The villi of the mucosa covering Peyer’s patches in the posterior jejunum were short and either conical or tongue-shaped; there were also small “pseudovilli” caused by bulges in the lymphoid tissue. Morphometry showed that the villi were longer in the anterior jejunum than in the duodenum and the posterior parts of the jejunum (P < 0.005). Morphologically fat absorption was most heavy in the anterior third of the small intestine. Moderate amounts of fat were also found in the epithelium of the posterior jejunum and of the abomasum. Large fat droplets were seen in apical duodenal enterocytes, in contrast to the small epithelial droplets in other areas with fat absorption. Nile blue staining indicated that the fat in the large droplets was esterified. 相似文献
Out of a total of 224 bovine eye secretions, 126 Moraxella bovis and 64 Neisseria ovis strains were isolated. The pathogenesis and histological lesions caused by Neisseria ovis have been studied on the eyes of three calves naturally affected with IBK, using electron microscopy.
Neisseria ovis caused in 1–12 weeks old calves acute, transient and mostly benign serous conjunctivitis with only slight affection of the cornea. More rarely erosions and even ulceration of the cornea have been observed.
Moraxella bovis and Neisseria ovis strains proved nearly unanimously sensitive in vitro to chloramphenicol, neomycin, oxytetracyclin, nitrofurantoin, erythromycin and cefoperazone. Other antibiotics and chemotherapeutics inhibited the growth of these agents only partly or were ineffective.
Experimental therapy has been carried out using a single i.m. injection of Terramycin/LA inj. (Pfizer) in a dose of 20 mg/kg body mass, repeated if necessary after 72–96 h. This formulation proved more effective and practical than treatments used earlier. 相似文献
Hydrogen peroxide (H2O2) localization and roles of peroxidases, malondialdehyde and reduced glutathione were compared in leaves of apricot (Prunus armeniaca) plants asymptomatic, European Stone Fruits Yellows (ESFY)-symptomatic and recovered. Nested PCR analysis revealed that Candidatus Phytoplasma prunorum, is present in asymptomatic, symptomatic and recovered apricot trees, confirming previous observations on this species, in which recovery does not seem to be related to the disappearance of phytoplasma from the plant.H2O2was detected cytochemically by its reaction with cerium chloride, which produces electron-dense deposits of cerium perhydroxides. H2O2was present in the plasmalemma of the phloem cells of recovered apricot plant leaves, but not in the asymptomatic or symptomatic material. Furthermore, by labelling apricot leaf tissues with diaminobenzidine DAB, no differences were found in the localization of peroxidases.Protein content in asymptomatic, symptomatic and recovered leaves was not significantly different from one another. In contrast, guaiacol peroxidase activity had the following trend: symptomatic > recovered > asymptomatic, whereas reduced glutathione content followed the opposite trend: asymptomatic > recovered > symptomatic. Moreover, no differences were observed in malondialdehyde concentrations between asymptomatic, symptomatic and recovered leaves. The overall results suggest that H2O2 and related metabolites and enzymes appear to be involved in lessening both pathogen virulence and disease symptom expression in ESFY-infected apricot plants. 相似文献