Evaluating the effectiveness of isolation distances for field plots of oilseed rape (Brassica napus) using a herbicide-resistance transgene as a selectable marker

The effectiveness of 200- and 400-m isolation distances were evaluated for small-scale trials of oilseed rape (Brassica napus L.). These distances have been used for previous transgenic release experiments and are commonly adopted for production of basic and certified breeders seed. A 400-m² donor plot contained plants with a dominant transgene conferring resistance to the herbicide glufosinate-ammonium. This character was used as a selectable marker to measure the frequency of hybrid formation in 400-m² target plots of non-transgenic rape. Seeds produced by the non-transgenic plants were permitted to fall onto the plots and allowed to germinate. At the first true-leaf stage, the plants were sprayed with glufosinate-ammonium. Surviving plants were resprayed, and a subsample assayed for the presence of the transgene using a colorimetric assay and Southern-blot analysis. The average frequency of hybridization over two replicates was 0.0156% at 200 m and 0.0038% at 400 m. These estimates are within the limits established for the production of basic seed (0.1%). Results indicated that bees were the most likely agent for long-distance pollen dispersal.     

Effects of methanol on the microflora of an arctic soil

The effect of 36 lm^?2 of 20% and 100% methanol spillage on the microflora of a soil near Inuvik, N.W.T. was assessed. Gas-liquid chromatography was used to monitor the residual methanol in the soil. Associated with residual methanol determination were measurements of changes in numbers of bacteria, fungal standing crop, respiration and isolation of methanol utilizing bacteria. Twenty percent methanol spillage had two different effects on the surface vegetation, in that the vegetation was killed in some plots and not others. The applied methanol disappeared completely between 1 and 4 weeks. No increased soil activity (as indicated by respiration, bacterial numbers, fungal standing crop) was detected when methanol was present in the soil. Because only one bacterium (i.e. pink gram negative rods) metabolized only very small concentrations of methanol, it was concluded that biodegradation of methanol was not a significant agent affecting methanol loss from the soil.     

The diagnosis and treatment of a thoracic abscess in an alpaca

A 6-month-old alpaca presented for lethargy, failure to thrive and leucocytosis. Diagnostic procedures, including thoracic ultrasound, radiographs and a computed tomography scan, were used to document a thoracic mass. Based on appearance and ultrasound-guided aspiration of purulent material, the mass was determined to be a large abscess. The abscess was treated with surgical drainage and long-term antibiotic therapy. The origin of this thoracic abscess was felt to be the caudal mediastinum, secondary to bacterial seeding of the caudal mediastinal lymph nodes. Although an aetiological agent was not definitively determined, the most likely was Actinomyces spp or Arcanobacterium pyogenes. The alpaca made a complete recovery following treatment.