Screening and identification of resistance to Leptosphaeria maculans (stem canker) in Brassica napus accessions

The occurrence of race-specific resistance genes to the stem canker fungus, Leptosphaeria maculans, was analysed in 453 accessions of B. napus, mainly originating from the Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) GeneBank. Major resistance genes Rlm1, Rlm2, Rlm4 and the putative RlmBBA gene were investigated using genetically improved strains of the fungus harbouring as few corresponding avirulence genes as possible. In addition, a screening with fully virulent isolates was used to uncover novel resistance sources. Major resistance genes were rarer in frequency and diversity in spring-type cultivars compared to winter types. In the former, 65.7% of the accessions were fully susceptible to all isolates, whereas only 12.2% of the winter types were devoid of at least one R gene. In spring cultivars, the most common R gene, Rlm4 was found in 26.6% of accessions, whereas the other R genes were rare. In winter cultivars, the most common R genes were Rlm2 (more than 45.9–54.0% of the accessions) and Rlm4 (26.4–27.7% of the genotypes). In winter types however, the improvement of the quality of oils, through the generation of single- and double-low genotypes improved the homogeneity of the cvs, whereas it impoverished R gene diversity, including the loss of complete resistance that was harboured by 18.4% of the less advanced accessions, and a reduction in the ratio of accessions harbouring Rlm1. Correlation between the R gene(s) present in the accessions and their field resistance is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Tree microhabitats at the stand scale in montane beech–fir forests: practical information for taxa conservation in forestry

Recent studies have highlighted the key role of tree microhabitats in forest habitat complexity and have suggested using them as surrogates for local taxonomic biodiversity. However, few practical guidelines have been published to help foresters in managing microhabitats at the stand scale. This paper provides scientific background information to help to develop such guidelines. We surveyed trees in nine long-unmanaged beech–fir forests to model tree microhabitat occurrence and diversity at the tree level. Data were upscaled to a size range of tree cluster, i.e., at the tree population scale, by aggregating observed values of microhabitat occurrence. Accumulation curves were used to estimate the minimum number of trees required to make all the microhabitat types available. Two managed forests were then studied to quantify management effects on microhabitats. Diameter at breast height (dbh) and tree species, respectively, explained 16 and 10 % of the variations in the number of microhabitat-bearing trees, and 21 and 10 % for the number of microhabitat types. Beech trees and firs with a dbh of less than dbh 50 and 65 cm, respectively, did not ensure the provision of all microhabitat types. At least 20 ha of unmanaged forest were necessary to conserve all the microhabitat types. Current management practices have reduced the number of microhabitat-bearing beeches both by reducing the number of very large trees (dbh > 67.5 cm) and by tree selection within mid-size diameters. For fir, only the logging of very large trees (dbh > 62.5 cm) negatively affected microhabitats. These figures may inspire guidelines for conservation-friendly forestry.     

Randomized, controlled study of inhaled fluticasone propionate, oral administration of prednisone, and environmental management of horses with recurrent airway obstruction

OBJECTIVE: To determine whether administration of glucocorticoids provides additional benefits to environmental management of horses with recurrent airway obstruction (RAO). ANIMALS: 28 horses with RAO. PROCEDURE: Horses were classified as having mild, moderate, or severe RAO. Within each category, horses were randomly assigned to receive inhaled fluticasone propionate, inhaled control substance, or oral administration of prednisone. During the 4-week study, horses were maintained outdoors and fed a pelleted feed. Clinical scores, pulmonary function, results of cytologic examination of bronchoalveolar lavage fluid (BALF), and adrenal gland function were determined before and 2 and 4 weeks after initiation of treatment. RESULTS: Clinical score and pulmonary function of all RAO-affected horses improved during the treatment period. After 4 weeks, clinical scores and pulmonary function of horses treated with a glucocorticoid were not different from those for the control treatment. In horses with severe RAO, treatment with fluticasone for 2 weeks resulted in significantly greater improvement in pulmonary function, compared with pulmonary function after treatment with prednisone or the control substance. Treatment with a glucocorticoid for 4 weeks and a low-dust environment did not have any effect on cellular content of BALF Treatment with prednisone for 2 weeks resulted in a significant decrease in serum cortisol concentration, compared with concentrations after administration of fluticasone or the control substance. CONCLUSIONS AND CLINICAL RELEVANCE: Environmental management is the most important factor in the treatment of horses with RAO. Early treatment with inhaled fluticasone can help accelerate recovery of horses with severe RAO.     

Suppurative spinal meningomyelitis in a dog with intra-neutrophilic cerebrospinal fluid cells Ehrlichia canis morulae

A 2-year-old castrated male Creole Shepherd mixed dog was presented for non-ambulatory paraparesis of the pelvic limbs. The magnetic resonance imaging and cerebrospinal fluid (CSF) analysis were consistent with meningomyelitis. Positive serology for Ehrlichia canis/Ehrlichia ewingii suggested exposure to a pathogen; qPCR on the serum and the CSF confirmed active infection. Ehrlichial morulae were observed within CSF and peripheral blood polymorphonuclear neutrophils; a species-specific PCR confirmed E. canis infection. This is an interesting report of E. canis infection in a dog with morulae observed in neutrophils both in the peripheral blood and CSF.     

Comparison of three ultrasound guided approaches to the lumbar plexus in dogs: a cadaveric study

ObjectiveTo assess the accuracy of contrast material injection and the dispersion of injectate following ultrasound guided injections at the level of L6 and L7, in canine cadavers.Study designProspective, randomized, experimental study.AnimalsTwenty nine mixed breed canine cadavers (28.9 ± 6.0 kg).MethodsThree ultrasound-guided approaches to the lumbar plexus (LP) were compared: 1) a dorsal pre-iliac approach at the level of L6; 2) a lateral paravertebral approach at mid-L6; and 3) a lateral paravertebral approach at mid-L7. An isovolumic mixture of iodine-based contrast with new methylene blue (0.1 mL kg⁻¹) was injected bilaterally in the juxta-foraminal region along the L6 or L7 nerve root. Computed tomography was performed followed by segmentation and 3D reconstruction of the lumbar spine and contrast material volumes using dedicated software. Distances between contrast material and the fifth through seventh lumbar foraminae, and length of femoral (FN) and obturator (ON) nerve staining were measured and compared between approaches (p < 0.05).ResultsInjectate moved cranial and caudal to the site of injection, and dispersed into an ovoid shape between the quadratus lumborum, iliopsoas and psoas minor muscles. Injections at L7 resulted in significantly closer contrast proximity to the L6 and L7 foraminae (p < 0.001). Femoral nerve staining was similar for all approaches, ON staining was more consistent after L7 injections (p < 0.001).Conclusion and clinical relevanceAn ultrasound-guided lateral paravertebral approach to the LP proved very practical and accurate, with easy visualization of the plexus and associated nerves. To ensure that the ON is covered by injectate, an approach at the level of L7 is recommended. Further studies are necessary to determine if this correlates with clinically effective local anesthesia.