A comparison of the potency of several Brucella allergens used to detect brucellosis in cattle

The potency of Brucella allergens prepared from a smooth Brucella abortus strain S-99, mucoid strain Leewarden, rough strain 45/20, and rough Brucella melitensis strain B-115 was assessed. The potency of these allergens was compared with that of a standard allergen prepared from smooth Brucella abortus S-99 that efficiently detected bovine brucellosis in other studies. Eight cattle experimentally inoculated with Brucella abortus 544 were tested with the allergens 4 and 10 weeks after infection, and again 8 months after infection. All the allergens effectively detected infection but there was a clear distinction in the mean skin reactions 48 and 72 h after injection of the allergens. The skin reactions provoked by the allergens prepared from smooth or mucoid strains of Brucella were most pronounced 48 h after injection. Skin reactions provoked by allergens prepared from rough strains of Brucella were strongest 72 h after injection. Allergens prepared from smooth or mucoid Brucella strains were more potent in detecting brucellosis than those prepared from rough strains of Brucella.Abbreviations Bruc/OCB Brucellergen OCB - cfu colony-forming units - CFT complement fixation test - ID-DLO Institute voor Dierhouderij en Diergezondheid-Dienst Landbouwkundig Onderzoek - ICFTU international complement fixation units - IU international units - LPS lipopolysaccharide - SAT serum agglutination test - SDTH skin delayed-type hypersensitivity     

Prehaustorial Resistance against Alfalfa Rust (Uromyces striatus) in Medicago truncatula

The legume species Medicago truncatula is gaining interests as a plant for structural and functional genomics that can be used to identify agronomically important genes in crop legumes. Resistance to the alfalfa rust (Uromyces striatus) was studied in a germplasm collection of M. truncatula. Accessions varied in resistance, as expressed by disease severity, but none showed macroscopically visible necrosis. Histological investigations, in selected lines covering the whole range of resistance reactions, revealed little difference in spore germination and none in orientation of germtubes on the leaf surface. However, appressorium formation on the stoma was significantly reduced in some accessions. Differences in resistance among accessions were more evident once the stoma were penetrated by the infection structures. Resistance was mainly due to a restriction of haustorium formation with varying levels of early abortion of the colonies, a reduction in the number of haustoria per colony, and hampered colony growth. In addition, necrosis of the host cells associated with infection hyphae was detectable in some accessions from the beginning of colony development. This information will be useful for eventual mapping and cloning analyses of resistance genes in M. truncatula that will in turn be useful for understanding other legume/rust interactions.     

Evaluation of compound 48/80 as a model of immediate hypersensitivity in the skin of dogs

Abstract The macroscopic and histological effects of intradermal injection of compound 48/80 were investigated in dogs. Dose-dependent increases in skin-fold thickness were induced at injection sites and histopathological examination of skin biopsy specimens revealed evidence of mast cell degranulation and cellular infiltration. Intradermal compound 48/80 may form a useful model for studies of canine hypersensitivity disorders including atopic dermatitis. Résumé— Les effets macroscopiques et histologiques de l'injection intradermique du composé 48/80 ont étéétudiés chez le chien. Une augmentation dose-dépendante de l'épaisseur du pli de peau a été induite au niveau des points d'injection et l'examen histopathologique de biopsies cutanées a démontré une dégranulation mastocytaire et une infiltration cellulaire. L'injection du composé 48/80 peut constituer un modèle utile pour l'étude de réactions d'hypersensibilité chez le chien, comme la dermatite atopique. [Mason, I., Lloyd, D. Evaluation of compound 48/80 as a skin model of immediate hypersensitivity in the skin of dogs (Evaluation du compose 48/80 comme modele d'hypersensibilité cutanee immediate chez le chien). Veterinary Dermatology 1996; 7 : 81–83.] Resumen Se investigaron los efectos macroscópicos e histológicos de la inyección intradérmica del compuesto 48/80. Estas inyecciones provocaron engrosamiento del grosor cutáneo proporcional a la dosis administrada y el examen histopatológico de biopsias cutáneas reveló degranulación de mastocitos e infiltración celular. El compuesto 48/80 puede constituir un modelo útil para el estudio de las hipersensibilidades caninas, incluyendo la dermatitis atópica. [Mason, I., Lloyd, D. Evaluation of compound 48/80 as a skin model of immediate hypersensitivity in the skin of dogs (Evaluación del compuesto 48/80 como modelo de hipersensibilidad inmediata en la piel del perro). Veterinary Dermatology 1996; 7 : 81–83.] Zusammenfassung— Die makroskopischen und histologischen Auswirkungen der intradermalen Injektion von Compound 48/80 wurden bei Hunden untersucht. Dosisabhängige Anstiege in der hautfaltendicke wurden an den Injektionsstellen induziert. Die histopathologische Untersuchung von Hautbioptaten zeigte das Auftreten von Mastzelldegranulation und zellulärer Infiltration. Intradermales Compound 48/80 könnte ein nützliches Modell für Untersuchungen kaniner Hypersensibilitätsprobleme einschließlich der atopischen Dermatitis darstellen. [Mason, I., Lloyd, D. Evaluation of com-pound 48/80 as a skin model of immediate hypersensitivity in the skin of dogs (Die Auswertung von compound 48/80 als Modell für die sofortige hypersensibilität in der haut des hundes). Veterinary Dermatology 1996; 7 : 81–83.]     

Characterization of new sources of resistance to Uromyces viciae-fabae in a germplasm collection of Vicia faba

A collection of 648 accessions of Vicia faba was screened for resistance to faba bean rust ( Uromyces viciae-fabae ). Two distinct types of resistance were identified, both resulting in reduced disease severity (DS) and area under the disease progress curve (AUDPC), but differing in the expression of hypersensitivity. One should be regarded as incomplete nonhypersensitive resistance and the other as incomplete resistance with late hypersensitivity. The hypersensitive resistance, which has not been reported before, was not dependent on temperature or plant age. These two types of resistance were characterized by three macroscopic components of resistance: increased latent period (LP), decreased colony size (CS) and a relatively reduced infection frequency (IF), both on seedlings and on adult plants. LP and CS were the components of nonhypersensitive resistance most highly correlated with DS and AUDPC measured under field conditions. The presence of necrosis was an additional component in the hypersensitive resistant response.     

An immune-complex glomerulonephritis of Chinook salmon, Oncorhynchus tshawytscha (Walbaum)

Chinook salmon from New Zealand were shown to have a generalized membranous glomerulonephritis that was most severe in large fish. Marked thickening of the glomerular basement membrane was the most consistent lesion, with the presence of an electron-dense deposit beneath the capillary endothelium.Severely affected glomeruli also had expansion of the mesangium and loss of capillaries,synechiae of the visceral and parietal epithelium and mild fibrosis of Bowmans capsule. Chinook salmon from British Columbia, Canada with bacterial kidney disease caused by Renibacterium salmoninarum had similar histological lesions. They also had thickened glomerular basement membranes that were recognized by rabbit antiserum to rainbow trout immunoglobulin. This was true only when frozen sections of kidney were used and not formalin-fixed tissue. An attempt to experimentally produce a glomerulopathy in rainbow trout by repeated immunization with killed R. salmoninarum was not successful. Case records from the Fish Pathology Laboratory at the University of Guelph over a 10-year period revealed that a range of species were diagnosed with glomerulopathies similar to those seen in Chinook salmon. The majority of these cases were determined to have chronic inflammatory disease. This report has identified the presence of immunoglobulin within thickened basement membranes of Chinook salmon with glomerulonephritis and supports the existence of type III hypersensitivity in fish.     

An unrecognized species of the Culicoides obsoletus complex feeding on livestock in the Netherlands

In studies on Culicoides attacking livestock in the Netherlands, we chanced upon a species of the Obsoletus complex that we do not recognize, but whose dark wing pattern is distinctive. Nine cytochrome c oxidase (CO1) sequences of our so-called ‘dark obsoletus’ support its status as a separate species, the sequences differing significantly from those representing Culicoides obsoletus (Meigen) (90–91% homology) and Culicoides scoticus Downes & Kettle (87–88% homology). In the last decade, several research groups in Europe have encountered ‘mystery species’ related to C. obsoletus and in some instances have made their sequences for various genetic loci available in GenBank. These include a CO1 series submitted from Sweden in 2012 (annotated as ‘obsoletus 01, 02, or 03 MA-2012′) and of which some share a 99% identity with our sequences for ‘dark obsoletus’. Without doubt, the series from the Netherlands, along with a portion of the Swedish submissions, together represent a single species (‘dark obsoletus’). Whether this species is referable to the Russian Culicoides gornostaevae Mirzaeva recorded recently from Norway, Sweden and Poland, and based solely upon the external morphology of the male, is not clear. The presence in Western Europe of multiple undescribed species related to C. obsoletus means that the taxonomy of this important vector complex is not fully resolved; consequently, we know little about these cryptic species with regard to seasonality, geographic range and host preference. This is undesirable given that Culicoides-borne arboviruses causing disease in livestock are moving more regularly out of the tropics and spreading north into temperate latitudes.     

阿胶泡腾颗粒对小鼠免疫功能的影响

研究了阿胶泡腾颗粒对小鼠免疫功能的影响.通过免疫器官重量法,考察了阿胶泡腾颗粒对小鼠中枢免疫器官和外周免疫器官发育的影响;通过碳廓清试验,考察了阿胶泡腾颗粒对巨噬细胞吞噬功能的影响;通过迟发型变态反应试验,考察了阿胶泡腾颗粒对小鼠细胞免疫功能的影响.结果表明,阿胶泡腾颗粒能增加免疫抑制小鼠的脾脏、胸腺指数,与空白对照组...