Soil microbial community characteristics along an elevation gradient in the Laguna Mountains of Southern California

We sampled soil at four sites in the Laguna Mountains in the western Sonoran Desert to test the effects of site and sample location (between or beneath plants) on fatty acid methyl ester (FAME) and carbon substrate ulilization (Biolog) profiles. The four sites differed in elevation, soil type, plant community composition, and plant percent cover. Soil pH decreased and plant density increased with elevation. Fertile islands, defined as areas beneath plants with greater soil resources than bare areas, are present at all sites, but are most pronounced at lower elevations. Consistent with this pattern, fertile islands had the greatest influence on FAME and Biolog profiles at lower elevations. Based on the use of FAME biomarker and principal components analyses, we found that soil microbial communities between plants at the lowest elevation had proportionally more Gram-negative bacteria than all other soils. At the higher elevation sites there were few differences in FAME profiles of soils sampled between vs. beneath plants. Differences in FAME profiles under plants among the four sites were small, suggesting that the plant influence per se is more important than plant type in controlling FAME profiles. Since microbial biomass carbon was correlated with FAME number (r=0.85,P<0.0001) and with FAME named (r=0.88,P<0.0001) and total areas (r=0.84,P<0.0001), we standardized the FAME data to ensure that differences in FAME profiles among samples were not the result of differences in microbial biomass. Differences in microbial substrate utilization profiles among sampling locations were greatest between samples taken under vs. between plants at the two lower elevation sites. Microbial substrate utilization profiles, therefore, also seem to be influenced more by the presence of plants than by specific plant type.     

Contagious ecthyma in the live sheep export industry

Objective: To investigate control options for contagious ecthyma (scabby mouth) in Australian sheep exported live to the Middle East.
Design: Prevalence, vaccination and modelling studies.
Procedure: One hundred and forty weaner sheep (less than 1 year old) on each of 106 farms in Western Australia (WA) and 18 farm groups of adult wethers received at a WA commercial feedlot were examined for lesions of scabby mouth. Sheep on a total of 26 farms in 3 States were divided into treatment and control groups for the vaccination study. A simple deterministic compartmental model was developed to establish which parameters had the greater effect on disease prevalence.
Results: The proportion of farms with evidence of scabby mouth in weaner sheep was 23.6% and, on those farms with the disease, the overall prevalence was 6.1%. At the feedlot, 4 out of 18 farm groups had 5 or more sheep with lesions on arrival. The overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccinated on farm before trucking to the feed-lot had a lower prevalence of scabby mouth at the end of simulated shipping than controls. The main determinant of scabby mouth prevalence was the proportion of sheep immune to the disease.
Conclusion: A program of vaccination for scabby mouth will reduce the prevalence of disease during live export. However, using current technology it is not possible to deliver shipments of sheep to the Middle East that are guaranteed completely free of scabby mouth.     

Metabolism of benomyl in carrot,strawberry and apple

The metabolism of benomyl was studied in carrots treated with high rates of benomyl, and in strawberries and apples treated at normal rates. The same metabolites were observed in both cases though, at normal rates, their concentrations were low but significant. Detected by means of gas-liquid chromatography they were: carbendazim, 2-aminobenzimidazole (2-AB), benzimidazole, 2-aminobenzonitrile, o-phenylene-diamine and the conjugates of carbendazim and 2-AB. o-Phenylenediamine has not hitherto been reported as a metabolite of benomyl. Two unidentified compounds were also observed by gas-liquid chromatography; their mass spectra were obtained by means of combined gas-liquid chromatography and mass spectrometry.     

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.