Pathogenicity of morphologically different isolates of <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis> with <Emphasis Type="Italic">Brassica napus</Emphasis> and <Emphasis Type="Italic">B. juncea</Emphasis> genotypes

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is a serious threat to oilseed production in Australia. Eight isolates of S. sclerotiorum were collected from Mount Barker and Walkway regions of Western Australia in 2004. Comparisons of colony characteristics on potato dextrose agar (PDA) as well as pathogenicity studies of these isolates were conducted on selected genotypes of Brassica napus and B. juncea. Three darkly-pigmented isolates (WW-1, WW-2 and WW-4) were identified and this is the first report of the occurrence of such isolates in Australia. There was, however, no correlation between pigmentation or colony diameter on PDA with the pathogenicity of different isolates of this pathogen as measured by diameter of cotyledon lesion on the host genotypes. Significant differences were observed between different isolates (P ≤ 0.001) in two separate experiments in relation to pathogenicity. Differences were also observed between the different Brassica genotypes (P ≤ 0.001) in their responses to different isolates of S. sclerotiorum and there was also a significant host × pathogen interaction (P ≤ 0.001) in both experiments. Responses between the two experiments were significantly correlated in relation to diameter of cotyledon lesions caused by selected isolates (r = 0.79; P < 0.001, n = 48). Responses of some genotypes (e.g., cv. Charlton) were relatively consistent irrespective of the isolates of the pathogen tested, whereas highly variable responses were observed in some other genotypes (e.g., Zhongyou-ang No. 4, Purler) against the same isolates. Results indicate that, ideally, more than one S. sclerotiorum isolate should be included in any screening programme to identify host resistance. Unique genotypes which show relatively consistent resistant reactions (e.g., cv. Charlton) across different isolates are the best for commercial exploitation of this resistance in oilseed Brassica breeding programmes.     

Oriented, multimeric biointerfaces of the L1 cell adhesion molecule: an approach to enhance neuronal and neural stem cell functions on 2-D and 3-D polymer substrates

This article focuses on elucidating the key presentation features of neurotrophic ligands at polymer interfaces. Different biointerfacial configurations of the human neural cell adhesion molecule L1 were established on two-dimensional films and three-dimensional fibrous scaffolds of synthetic tyrosine-derived polycarbonate polymers and probed for surface concentrations, microscale organization, and effects on cultured primary neurons and neural stem cells. Underlying polymer substrates were modified with varying combinations of protein A and poly-D-lysine to modulate the immobilization and presentation of the Fc fusion fragment of the extracellular domain of L1 (L1-Fc). When presented as an oriented and multimeric configuration from protein A-pretreated polymers, L1-Fc significantly increased neurite outgrowth of rodent spinal cord neurons and cerebellar neurons as early as 24 h compared to the traditional presentation via adsorption onto surfaces treated with poly-D-lysine. Cultures of human neural progenitor cells screened on the L1-Fc/polymer biointerfaces showed significantly enhanced neuronal differentiation and neuritogenesis on all protein A oriented substrates. Notably, the highest degree of βIII-tubulin expression for cells in 3-D fibrous scaffolds were observed in protein A oriented substrates with PDL pretreatment, suggesting combined effects of cell attachment to polycationic charged substrates with subcellular topography along with L1-mediated adhesion mediating neuronal differentiation. Together, these findings highlight the promise of displays of multimeric neural adhesion ligands via biointerfacially engineered substrates to "cooperatively" enhance neuronal phenotypes on polymers of relevance to tissue engineering.     

A rapid high-precision flow cytometry based technique for total white blood cell counting in chickens

The automated analysis of total white blood cell count and white blood cell differentials is routine in research and clinical diagnosis in mammalian species. In contrast, in avian haematology these parameters are still estimated by conventional microscopic procedures due to technical difficulties associated with the morphological peculiarities of avian erythrocytes and thrombocytes. Both cell types are nucleated and fairly resistant to cell lysis, a prerequisite for automated leukocyte quantification and differentiation by commercial instruments. By using an anti-CD45 monoclonal antibody in combination with selected subset specific markers we have established a simple (no-lyse no-wash single-step one-tube) flow cytometry based technique for high precision chicken blood cell quantification. EDTA-blood samples are diluted, spiked with fluorescence beads and incubated with a mixture of fluorochrome conjugated chicken leukocyte specific antibodies. We demonstrate that total leukocyte numbers as well as thrombocyte, monocyte, T-cell, B-cell and heterophilic granulocyte numbers can be determined by flow cytometry in a single step without prior cell lysis, cell separation or cell washing steps. Importantly, we also show that blood samples can be fixed prior to cell staining which enables shipping of samples making the technology widely available. Comparison of this technique with conventional microscopy revealed superior precision. By comparing leukocyte differentials of two chicken populations and during immune system development after hatch we demonstrate that large sample numbers can be analysed within hours. This technique will help to overcome previous restrictions in immune status analysis in chickens in experimental systems, during vaccine testing and health status monitoring in chicken flocks. Advances in avian genomics should facilitate the development of appropriate tools for other avian species in the future which will make this technique broadly applicable.     

Antimicrobial susceptibility of bacterial isolates from 233 horses with musculoskeletal infection during 1979-1989.

Bacterial culture and susceptibility results were analysed from 233 horses with septic arthritis/tenosynovitis or osteomyelitis that developed after fracture repair. Antibiotics were deemed highly effective, effective or ineffective if > or = 85%, 70-84.9% or < 70% of the isolates were susceptible respectively. In total, 424 bacterial types were isolated; 386 were aerobic or facultative and 38 were anaerobic. Enterobacteriaceae (28.8%) were the most common bacterial group isolated, followed by non-beta-haemolytic streptococci (13.0%), coagulase-positive staphylococci (11.8%), beta-haemolytic streptococci (9.4%), and coagulase-negative staphylococci (7.3%). The remainder of the organisms were other Gram-negative (15.8%), other Gram-positive (2.3%) and miscellaneous (2.6%) bacteria. Penicillin and ampicillin were highly effective against beta-haemolytic streptococci, but were ineffective against other bacteria. Ampicillin was no more effective than penicillin against most bacteria. Amikacin was the most effective antibiotic against the wide range of bacteria isolated in this study. Amikacin was highly effective against coagulase-positive staphylococci, Enterobacteriaceae and Pseudomonas and was effective against coagulase-negative staphylococci and Actinobacillus. Gentamycin was not highly effective against any bacterial group; but was effective against coagulase-positive and negative staphylococci, Pseudomonas, Salmonella and Actinobacillus. Kanamycin was ineffective against all bacteria with the exception of Actinobacillus. Cephalothin was highly effective against beta-haemolytic streptococci, coagulase-positive staphylococci and Actinobacillus and was effective against coagulase-negative staphylococci.(ABSTRACT TRUNCATED AT 250 WORDS)     

Failure of pH to predict ionized calcium percentage in healthy horses

Blood, serum, and plasma total calcium concentrations and plasma and serum ionized calcium concentrations were anaerobically determined by use of a calcium-specific electrode for samples obtained from 39 healthy horses. Mean (+/- SD) serum ionized calcium concentration was 6.6 +/- 0.3 mg/dl (1.6 +/- 0.1 mmol/L) and the mean serum ionized calcium percentage was 58.2 +/- 3.4%. Serum ionized calcium percentage was not significantly correlated with serum pH. Plasma ionized calcium percentage was weakly correlated with plasma pH (r = -0.480; P less than or equal to 0.05). Ionized calcium concentration was determined in serum samples manipulated in vitro by additions of 1 to 80 microliters of 0.1N hydrochloric acid or sodium hydroxide to yield 6 to 10 pH values between 6.8 and 8.2. In all horses, the relationship between serum ionized calcium percentage and serum pH at these pH values was then examined by use of a repeated-measures multiple regression analysis. Correlations between serum ionized calcium percentage and adjusted serum pH value for each horse were highly significant (P less than or equal to 0.05); however, analysis of pooled data from all horses indicated that a statistically significant relationship between serum pH and ionized calcium percentage did not exist. Lack of a significant relationship between these variables was most likely attributable to heterogeneity of variance of ionized calcium percentage among horses, reflecting variation in undefined biochemical constituents of serum that affect the equilibrium of calcium binding. When it is essential to evaluate the calcium status of a horse, direct measurement of serum ionized calcium concentration is recommended.     

Radula Tooth Structure of the Gastropod Conus imperialis Elucidated by Scanning Electron Microscopy

Scanning electron microscopy of the hollow, harpoon-like radula tooth of the toxoglossan gastropod Conus has elucidated the structure and relationships of its component parts: apex, cutting edge, barbs, serration, adapical and basal openings of the lumen, external and internal folds of the shaft, and base. The functional roles of these components in prey capture are proposed.     

Gaschromatographische Untersuchungen an elektronenbestrahlten Fetten

Zusammenfassung Untersuchungen über die chemischen Veränderungen in Fetten, die mit 100 Mrad bestrahlt wurden, ergaben, daß Verbindungen mit mittelkettigen Fettsäuren entstehen. Neben einer Abspaltung endständiger Methylgruppen tritt besonders eine Trennung der mittelständigen C-C-Bindungen auf, wodurch gesättigte und ungesättigte C₆- bis C₁₁-Bruchstücke nachweisbar werden. Die Doppelbindungen selbst sind relativ stabil, doch werden die der Doppelbindung benachbarten C-C-Einfachbindungen bevorzugt gespalten. Neben der Bildung von Fettsäuren findet auch eine solche von Carbonylverbindungen statt. Mehr als 20 verschiedene Ketone und Aldehyde konnten gaschromatographisch nachgewiesen werden. Die Aufspaltung der Ester-C-O-C-Bindung ist meist von einer Zerstörung der Fettsäurekette begleitet, wodurch Carbonylverbindungen mit 6 bis 12 C-Atomen entstehen. Relativ große Mengen von ungesättigten C₉-Ketonen und geringe Menge von Ketonen mit mehr als 13 C-Atomen werden in bestrahltem Tripalmitin sowie in bestrahlter Palmitinsäure gefunden. In ungesättigten Ölen treten diese Verbindungen nicht auf, dagegen enthalten diese mehr C₁₁-und C₁₂-Ketone.

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Summary Experiments on the chemical transformation of fats irradiated at 100 Mrads have shown the formation of fatty acid, median-branched bonds.Besides a separation of terminal branchings of methyl groups appears more particularly a scission of the median branchings C-C, following which saturated and unsaturated fragments from C₆ to C₁₁ have been made apparent. The double bonds themselves are relatively stable, while the single bonds adjacent to the double one, are in majority separated. Aside from the formation of fatty acids occurs also the formation of carbonyl bonds.More than 20 different ketones and aldehydes have been detected by gas chromatography. The scission of the bond ester-C-O-C is generally accompanied by a destruction of the fatty acid chain, following which appears the carbonyl bonds, with 6 to 12 atoms of carbon.Relatively great quantities of unsaturated C₉ ketones and small quantities of ketones with more than 13 atoms of carbon have been found in irradiated tripalmitin and in irradiated palmitic acid. In unsaturated oils these compounds are not found, but, on the other hand these oils have a greater content in C₁₁ and C₁₂ ketones.

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Résumé Des expériences sur les transformations chimiques des matières grasses, irradiées à 100 Mrad, ont montré la formation de liaisons à branchements médians d'acides gras.A côté d'une séparation de branchements terminaux de groupes méthyles, apparait en particulier une scission des branchements médians C-C, à la suite de laquelle des fragments saturés et non saturés de C₆ jusqu'à C₁₁ ont été mis en évidence. Les liaisons doubles mêmes sont relativement stables, cependant les liaisons simples, voisines à la liaison double, se trouvent en prédominance séparées.A côté de la formation d'acides gras, la formation de liaisons carbonylées a également lieu.Plus de 20 différents cétones et aldéhydes ont pu être mis en évidence par la chromatographie en phase gazeuse. La scission de la liaison ester-C-O-C-est généralement accompagnée d'une destruction de la chaîne d'acide gras, à la suite de laquelle naissent les liaisons carbonylées de 6 à 12 atomes de carbone.Des quantités relativement grandes des cétones C₉ non saturés et de petites quantités de cétones avec plus de 13 atomes de carbone ont été trouvées dans la tripalmine irradiée, ainsi que dans l'acide palmitique irradié. Dans les huiles non saturées, ces combinaisons ne se trouvent pas, par contre ces huiles contiennent davantage de cétones C₁₁ et C₁₂.

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mit 3 Fig.