Rapid and sensitive plate method for detection of Aspergillus fumigatus.
(65/2075)
The routine identification of Aspergillus fumigatus in clinical samples involves, apart from direct examination, the isolation of the organism on a plate followed by its microscopic characterization. This approach lacks sensitivity, specificity, and speed. A new procedure has been developed combining microcolony formation on a nylon membrane filter at 45 degrees C with the detection of a specific 4-methylumbelliferyl-alpha-L-arabinopyranoside cleaving enzyme activity in digitonin permeabilized cells. The test takes approximately 14 h and has an efficiency of 98.2% and false-positive and -negative rates of 0 and 3.1%, respectively. When applied to 188 clinical samples taken from patients with proven or nonproven presence of Aspergillus species, a good agreement with the conventional plate-microscopy method was obtained. (+info)
Immunopharmacological activity of Echinacea preparations following simulated digestion on murine macrophages and human peripheral blood mononuclear cells.
(66/2075)
We have investigated the immunostimulatory, anti-inflammatory, and antioxidant activities of various Echinacea raw materials and commercially available products on murine macrophages and human peripheral blood mononuclear cells (PBMCs). To emulate oral dosing, a simulated digestion protocol was employed as a means of sample preparation. Echinacea-induced macrophage activation was used as a measure of immunostimulatory activity determined via quantitative assays for macrophage-derived factors including tumor necrosis factor alpha, interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10, and nitric oxide. Echinacea herb and root powders were found to stimulate murine macrophage cytokine secretion as well as to significantly enhance the viability and/or proliferation of human PBMCs in vitro. In contrast, Echinacea extracts chemically standardized to phenolic acid or echinacoside content and fresh pressed juice preparations were found to be inactive as immunostimulatory agents but did display, to varying degrees, anti-inflammatory and antioxidant properties. (+info)
Lifetime and rotational relaxation time of dansylgalactoside bound to the lac carrier protein.
(67/2075)
The results presented in this paper demonstrate that the excited state lifetime, anisotropy, and rotational relaxation time of 2'-(N-dansyl)aninoethyl 1-thio-beta-D-galactopyranoside (DG2) increase when the probe is bound specifically to the lac carrier protein in "energized" Escherichia coli membrane vesicles. Although the probe also binds nonspecifically to the vesicle membrane, such binding is independent of the lac carrier protein and is unaffected by "energization" of the vesicles. The experiments provide further evidence that the dansylgalactosides are useful probes for the beta-galactoside transport system and support the hypothesis that the changes in dansylgalactoside fluorescence observed on "energization" of membrane vesicles reflect changes in the binding of the probe. (+info)
Inactivation of a MAPK-like protein kinase and activation of a MBP kinase in germinating barley embryos.
(68/2075)
We provide evidence for involvement of two different 45 kDa protein kinases in rehydration and germination of barley embryos. In dry embryos, a myelin basic protein (MBP) phosphorylating kinase was detected, which could be immunoprecipitated with an anti-MAPK (mitogen-activated protein kinase) antibody. Rehydration of the embryo induced a decrease in activity of this 45 kDa MAPK-like protein kinase. In addition, activity of a MBP kinase of the same molecular weight was subsequently found to be induced. This second MBP kinase activity could not be immunoprecipitated with the anti-MAPK antibody and was induced only in germinating embryos, not in dormant embryos. (+info)
Simocyclinones, novel cytostatic angucyclinone antibiotics produced by Streptomyces antibioticus Tu 6040. I. Taxonomy, fermentation, isolation and biological activities.
(69/2075)
Two novel angucyclinone-type antibiotics, simocyclinones D4 and D8, were detected in the mycelium extract of Streptomyces antibioticus Tu 6040 by HPLC-diode-array and HPLC-electrospray-mass-spectrometry screening. The compounds show antibiotic activities against Gram-positive bacteria and cytostatic effects on various tumor cell lines. (+info)
Mechanisms underlying impaired GLUT-4 translocation in glycogen-supercompensated muscles of exercised rats.
(70/2075)
Exercise training induces an increase in GLUT-4 in muscle. We previously found that feeding rats a high-carbohydrate diet after exercise, with muscle glycogen supercompensation, results in a decrease in insulin responsiveness so severe that it masks the effect of a training-induced twofold increase in GLUT-4 on insulin-stimulated muscle glucose transport. One purpose of this study was to determine whether insulin signaling is impaired. Maximally insulin-stimulated phosphatidylinositol (PI) 3-kinase activity was not significantly reduced, whereas protein kinase B (PKB) phosphorylation was approximately 50% lower (P < 0.01) in muscles of chow-fed, than in those of fasted, exercise-trained rats. Our second purpose was to determine whether contraction-stimulated glucose transport is also impaired. The stimulation of glucose transport and the increase in cell surface GLUT-4 induced by contractions were both decreased by approximately 65% in glycogen-supercompensated muscles of trained rats. The contraction-stimulated increase in AMP kinase activity, which has been implicated in the activation of glucose transport by contractions, was approximately 80% lower in the muscles of the fed compared with the fasted rats 18 h after exercise. These results show that both the insulin- and contraction-stimulated pathways for muscle glucose transport activation are impaired in glycogen-supercompensated muscles and provide insight regarding possible mechanisms. (+info)
New 1-O-acyl alpha-L-rhamnopyranosides and rhamnosylated lactones from Streptomyces sp., inhibitors of 3 alpha-hydroxysteroid-dehydrogenase (3alpha-HSD).
(71/2075)
Chemical screening with extracts of Streptomyces sp. (strain GT 61150) resulted in the detection, isolation, and structure elucidation of two new acyl alpha-L-rhamnopyranosides (1 and 2) and three new rhamnosyllactones A, B1 and B2 (3 approximately 5). Rhamnosyllactones B1 and B2 were obtained as a 5:1 mixture. The structures were confirmed by spectroscopic analysis, especially 2D-NMR techniques. The rhamnosyltransferase of our strain is able to connect the sugar moiety to heteroaromatic carboxylic acids and enols. The metabolites 1 and 4/5 as well as previously reported acylrhamnosides 6 approximately 11 inhibit the enzyme 3alpha-hydroxysteroid-dehydrogenase (3alpha-HSD). (+info)
Mouse toxicity and cytokine release by verotoxin 1 B subunit mutants.
(72/2075)
The crystal structure of the verotoxin 1 (VT1) B subunit complexed with a globotriaosylceramide (Gb(3)) analogue showed the presence of three receptor binding sites per monomer. We wished to study the effects of altering the three sites, singly or in combination, on animal toxicity and cytokine induction in vitro. We found that while the site 1 and 2 mutants were modestly (two- to sevenfold) reduced in their ability to cause disease in BALB/c mice, the site 3 mutant, W34A, was as toxic as VT1. However, all the double-mutant proteins, irrespective of which two sites were mutated, exhibited approximately a 100-fold reduction in their 50% lethal doses for mice. These results suggest that multivalent receptor binding is important in vivo and that all three binding sites make a similar contribution to the latter process. The triple-mutant holotoxin, F30A G62T W34A, administered intraperitoneally without adjuvant, stimulated a strong antibody response in BALB/c mice, and the immune sera neutralized the activity of VT1 in vitro. Induction of tumor neurosis factor alpha release from differentiated human monocytes (THP-1 cells) was relatively impaired for site 1 and site 2 but not site 3 mutants, suggesting an auxiliary role for the latter site in mediation of cytokine release in vitro. Cytotoxicity assays on undifferentiated THP-1 cells have also demonstrated the importance of sites 1 and 2 and the relatively small role played by site 3 in causing cell death. These data suggest an association between the cytotoxicity of the protein and its ability to induce cytokine release. (+info)