Characteristics of Pustula tragopogonis (syn. Albugo tragopogonis) Newly Occurring on Cultivated Sunflower in Germany

In temperate climates, Pustula tragopogonis is rarely found on cultivated sunflower. In Europe, it was so far of little economic impact on other Asteraceae, except for some regions in the Mediterranean. In 2003, P. tragopogonis was found for the first time in sunflower fields in southern Germany. The pathogen has a widespread occurrence there, especially in the region around Stuttgart, BW. Fatty acid profiling, ultrastructural investigation and ITS sequencing revealed a high similarity to an 2002 isolate from southern Africa and an 2005 isolate from Australia, but revealed significant differences to P. tragopogonis s.l. on Cirsium arvense, a common weed, growing on or in the vicinity of sunflower fields in Germany. P. tragopogonis from this host can therefore be excluded from being the source of the reported infection.     

Modeling of orthokinetic flocculation of Saccharomyces cerevisiae.

This study examined the flocculation behavior of two Saccharomyces cerevisiae strains expressing either Flo1 (LCC1209) genotype or NewFlo (LCC125) phenotype in a laminar flow field by measurement of the fundamental flocculation parameter, the orthokinetic capture coefficient. This orthokinetic capture coefficient was measured as a function of shear rate (5.95-223 s(-1)) and temperature (5-45 degrees C). The capture coefficients of these suspensions were directly proportional to the inverse of shear rate, and exhibited an increase as the temperature was increased to 45 degrees C. The capture coefficient of pronase-treated cells was also measured over similar shear rate and temperature range. A theory, which predicts capture coefficient values due to zymolectin interactions, was simplified from that developed by Long et al. [Biophys. J. 76: (1999) 1112]. This new modified theory uses estimates of: (1) cell wall densities of zymolectins and carbohydrate ligands; (2) cell wall collision contact area; and (3) the forward rate coefficient of binding to predict theoretical capture coefficients. A second model that involves both zymolectin interactions and DLVO forces was used to describe the phenomenon of yeast flocculation at intermediate shear ranges, to explain yeast flocculation in laminar flow.     

Blueberry flavonoids inhibit matrix metalloproteinase activity in DU145 human prostate cancer cells.

Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction, an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.     

Isolation of Actinobacillus suis from a Canada goose (Branta canadensis)

Blindness from conjunctivitis caused by Actinobacillus suis was found in a Canada goose (Branta canadensis) from a wildlife refuge in Kentucky. Lesions were not observed elsewhere and other body organs were grossly normal. Actinobacillus spp. in birds is rare and this is apparently the first report of conjunctivitis resulting from this infection in waterfowl.     

Beta-adrenergic agonists and cyclic AMP decrease intracellular resting free-calcium concentration in ileum smooth muscle

Intracellular free-calcium levels were measured in strips of longitudinal smooth muscle from guinea-pig ileum; fura-2 was used as a calcium monitor. At rest the calcium concentration was about 180 nM, and this rose to 300-400 nM following electrical stimulation and during spontaneous calcium transients (all measurements at 23-25 degrees C). Isoprenaline suppressed the spontaneous calcium transients, and reduced the resting calcium level to about 130 nM. This fall in resting calcium concentration was seen even in muscle strips which did not have spontaneous activity. Elevation of intracellular cyclic AMP levels, produced by forskolin or dibutyryl cyclic AMP, mimicked the actions of isoprenaline. We conclude that the relaxant effects of beta-adrenergic agonists of visceral smooth muscle may be explained partly by a fall in intracellular resting free-calcium level, mediated via an increase in cyclic AMP.     

Critical considerations in the development of an assay for sulfidopeptide leukotrienes in plasma

A sensitive and specific assay has been developed for measurement of total sulfidopeptide leukotrienes (LT) in plasma. LTC4 and LTD4 in plasma are converted to LTE4 which is then extracted by C18 Sep-Pak binding and elution. Total LTE4 is resolved by reverse phase high performance liquid chromatography (RP-HPLC) and quantitated by radioimmunoassay (RIA). A [3H]LTE4 internal standard is added to the starting plasma sample to allow overall recovery to be calculated and to define the fractions from RP-HPLC to be assayed for LTE4-like immunoreactivity. The correlation between the measured increase in LTE4 concentration after addition of incremental amounts of LTC4 and LTE4 to plasma was 0.989 and 0.978, respectively, with slopes of 1.05 and 1.11. Addition of 51 pg/ml LTE4 to 5 ml plasma was detectable; the measured increase was 48 +/- 12 pg/ml (mean +/- SE, n = 7). The intra-assay coefficient of variation for 341 pg/ml of added LTC4 was 3.2% (n = 6). Sulfidopeptide leukotrienes could not be detected in blood samples taken from 12 normal volunteers in whom the theoretical detection limit, calculated from the sensitivity of the RIA, the overall recovery of LTE4, and the volume of plasma extracted, was 83 +/- 4 pg LTE4/ml plasma (0.19 +/- 0.01 pmol sulfidopeptide leukotriene/ml plasma; mean +/- SE).