Impact of time between field application of Bacillus subtilis strains SB01 and SB24 and inoculation with Sclerotinia sclerotiorum on the suppression of Sclerotinia stem rot in soybean

This study evaluated the impact of time between the application of cell suspensions or cell-free filtrates of Bacillus subtilis strains SB01 or SB24 on soybean plants under field conditions and inoculation with Sclerotinia sclerotiorum on their effectiveness for suppression of S. sclerotiorum. The results showed that the cell suspensions of two strains provided greater effectiveness than the cell-free filtrates, but the suppression effectiveness decreased as the time between application in the field and S. sclerotiorum inoculation increased. The B. subtilis cell suspensions applied on soybean leaves for up to 10 days under field conditions were able to provide a significant (P < 0.01) reduction in disease severity by approximately 20–90% at 5 days after the S. sclerotiorum inoculation. When rated 15 days after S. sclerotiorum inoculation, plants treated with bacterial cells for ≤6 days reduced Sclerotinia stem rot severity by 15–70%. Most effectiveness was provided by the cell suspensions present on soybean leaves for <3 days under field conditions, which significantly (P < 0.01) reduced disease severity by 40–70% over 15 days. In comparison, the cell-free filtrates remaining on leaves for <6 days significantly (P < 0.01) reduced disease severity during the first 5 days after the inoculation, while the best cell-free filtrate treatments were those with ≤1-day intervals, which significantly (P < 0.01) reduced disease severity by 10–40% during 15 days after the inoculation. The effectiveness of B. subtilis was reduced when it rained after application.     

Spatial and Seasonal Variations in Nitrogen Leaching and Acidity across Four Acid-impacted Regions of the UK

This study examines the seasonal variability in levels of nitrogen (N) leaching and acidity in four acid impacted upland regions of the UK: the South Pennines, Snowdonia, Galloway and the Mourne Mountains. All regions are acidified, with median pH values of <5.5. The South Pennines exhibit excess sulphate concentrations an order of magnitude higher than those for other regions and have the lowest pH values of all the regions. Nitrate concentrations are highest in the South Pennines (seasonal medians 20–26 μeq l^?1) and the Mourne Mountains (seasonal medians 9–26 μeq l^?1). Surface water in the Mourne Mountains is the most highly N impacted in terms of the proportional contribution of N to acidity. All N species exhibit seasonality, with greater retention by catchment soils and vegetation in August. This seasonality is most marked in Snowdonia and least marked in the South Pennines. This implies that the South Pennines have reached an advanced stage of N saturation. Despite the reductions in S deposition, xSO₄ is the dominant anion for all sites in the South Pennine and Snowdonia regions. A strong negative relationship between the contribution of NO₃ to total acidity and DON was observed for all regions except the South Pennines. It is hypothesized that catchments dominated by organic rich soils produced more DON and have an increased capacity to immobilise NO₃. Seasonal nitrogen budgets show that over 60% of the N inputs are retained within catchments, and no site retains all incoming N throughout the year.     

Eradication of over-wintering mildew (Podosphaera leucotricha) in apple buds by nitrogen-containing surfactants

The eradicant activities of 24 nitrogen-containing preparations, comprising primary, secondary or tertiary amines, amine acetates, diamines, amine oxides or quaternary ammonium salts, were assessed in trials with potted dormant apple rootstocks, heavily infected with the powdery mildew fungus Podosphaera leucotricha. The surfactants consisted of mixtures in which C₁₂/C₁₄ or C₁₆/C₁₈ alkyl or alkenyl compounds predominated. Of the amine acetates (at 50g litre^?1), only the formulation containing C₁₂/C₁₄ primary amine acctates was considered worthy of further evaluation. Some amine oxides and quaternary ammonium compounds (at 35 g litre^?1) were good eradicants and were as effective as ‘PP222’ a (nonylphenol-ethoxylate mixture) which was included for comparison. All the compounds showing good activity contained one C₁₂/C₁₄ alkyl group whereas C₁₆/C₁₈ compounds, whether saturated or unsaturated, were relatively inactive. In a field trial, C₁₂/C₁₄ (dimethyl) amine oxide, C₁₂/C₁₄bis (2-hydroxyethyl) amine oxide, and C₁₂/C₁₄ amine acetate (35 g litre^?1) greatly reduced the amount of primary mildew on trees that were previously heavily infected, but there were signs that the fruit yield was reduced.     

Using 3D animations to teach intracellular signal transduction mechanisms: taking the arrows out of cells

Traditional methods of teaching intracellular biological processes and pathways use figures or flowcharts with the names of molecules linked with arrows. Many veterinary students, presented with such material, simply memorize the names or chemical structures of the molecules and are then likely to forget the material once the examination is completed. To address this problem, the authors designed, created, and field-tested new teaching media that incorporate realistic three-dimensional (3D) animations depicting the dynamic changes that occur in intracellular molecules during cellular activation. Testing found that veterinary students taught using traditional teaching media (e.g., lectures, handouts, textbooks) are proficient in memorizing the names and order of intracellular molecules but unable to appreciate the interactions between these elements or their spatial relationships within cells. In contrast, more than 90% of veterinary students taught using 3D animations not only recall the facts about the intracellular elements but also develop accurate mental images of the interactions among these molecules and their spatial relationships. These findings strongly suggest that the comprehension of complex biological processes by veterinary students can be enhanced by the use of dynamic 3D depictions of these processes in the classroom.     

Evaluation of a point-of-care immunodot assay for predicting results of allergen-specific intradermal and immunoglobulin E serological tests

Immunotherapy to prevent recurrence of clinical signs of atopic dermatitis (AD) is based on intradermal or serological tests that assist in identifying allergen-specific immunoglobulin E hypersensitivities. Unfortunately, the results of such tests can be negatively influenced by several factors, which include the age of the patients, the season of testing and the administration of anti-allergic drugs. Screening to predict when these expensive tests will be useful would benefit owners of dogs with AD. The objectives of this study were to determine whether a point-of-care allergen-specific immunodot assay (Allercept E-Screen, Heska Corp., Ft Collins, CO, USA) could predict results of either intradermal or Allercept full panel serological tests in atopic dogs. Thirty dogs living in the south-eastern USA were diagnosed with AD in accordance with current standards. Allergen-specific intradermal, serological and E-Screen tests were performed in all subjects. For flea, house dust mite and pollen allergens altogether, results of the E-Screen assay agreed with those of intradermal and serological tests in 26/30 dogs (87%) and 25/30 dogs (83%), respectively. In this group of dogs, the probabilities of obtaining intradermal or serological tests positive for these allergens were 70 and 67%, respectively. If either skin or serum tests were performed only in dogs with positive E-Screen tests, the probability of obtaining positive results would be increased from 70 to 95% and from 67 to 90%, respectively. In this population of dogs with AD, results of the E-Screen point-of-care immunodot assay was found to often agree with those of allergen-specific intradermal or Allercept tests for selected allergen groups.