Investigation of the influence of EPs 7630, a herbal drug preparation from Pelargonium sidoides, on replication of a broad panel of respiratory viruses

The Pelargonium sidoides extract EPs^® 7630 is an approved drug for the treatment of acute bronchitis in Germany. The postulated mechanisms underlying beneficial effects of EPs^® 7630 in bronchitis patients include immunomodulatory and cytoprotective effects, inhibition of interaction between bacteria and host cells, and increase of cilliary beat frequency on respiratory cells. Here, we investigated the influence of EPs^® 7630 on replication of a panel of respiratory viruses. Determination of virus-induced cytopathogenic effects and virus titres revealed that EPs^® 7630 at concentrations up to 100 μg/ml interfered with replication of seasonal influenza A virus strains (H1N1, H3N2), respiratory syncytial virus, human coronavirus, parainfluenza virus, and coxsackie virus but did not affect replication of highly pathogenic avian influenza A virus (H5N1), adenovirus, or rhinovirus. Therefore, antiviral effects may contribute to the beneficial effects exerted by EPs^® 7630 in acute bronchitis patients.     

Hydrodynamic experiments on dacryoconarid shell telescoping

It is not uncommon that small conical dacryoconarid shells are found inserted one into another. Although this phenomenon has been studied for decades, and interparticle collisions in turbulent flows have largely considered to be responsible, no satisfactory explanation has been provided. We performed experiments under laboratory conditions using narrow aluminium cones as replicas of these shells. Two different flow regimes were tested to mimic the probable hydrodynamic conditions in the ocean. First, large‐scale rhythmic back and forth coherent motion of water over the seabed was reproduced in an oscillating sloshing tank (sloshing mode). Second, small‐scale irregular stirring motion in turbulent bulk was imitated in cylindrical containers placed into a shaker (mixing mode). With sloshing, a high production of irreversibly telescoped cones was present in clear water and at driving frequencies comparable to the upper limits known for sea waves. With shaking, both coalescence and break‐up of the cones were observed, as the quasi‐random hydrodynamic forces generated by vigorous liquid motion were roughly comparable with the mechanical forces holding the cones together. However, the stability of the clusters of telescoped cones in the shaker could be enhanced with the addition of fine solid particles (suspended silt). In addition, a simple mathematical model was suggested for the flow interaction with a submerged conical particle in the case of the sloshing mode, providing an interesting insight into the evolution of strong deceleration zones.     

Pyranose 2-dehydrogenase, a novel sugar oxidoreductase from the basidiomycete fungus Agaricus bisporus

A novel C-2-specific sugar oxidoreductase, tentatively designated as pyranose 2-dehydrogenase, was purified 68-fold to apparent homogeneity (16.4 U/mg protein) from the mycelia of Agaricus bisporus, which expressed maximum activity of the enzyme during idiophasic growth in liquid media. Using 1,4-benzoquinone as an electron acceptor, pyranose 2-dehydrogenase oxidized d-glucose to d-arabino-2-hexosulose (2-dehydroglucose, 2-ketoglucose), which was identified spectroscopically through its N,N-diphenylhydrazone. The enzyme is highly nonspecific. d-,l-Arabinose, d-ribose, d-xylose, d-galactose, and several oligosaccharides and glycopyranosides were all converted to the corresponding 2-aldoketoses (aldosuloses) as indicated by TLC. d-Glucono-1,5-lactone, d-arabino-2-hexosulose, and l-sorbose were also oxidized at significant rates. UV/VIS spectrum of the native enzyme (λ_max 274, 362, and 465 nm) was consistent with a flavin prosthetic group. In contrast to oligomeric intracellular pyranose 2-oxidase (EC 1.1.3.10), pyranose 2-dehydrogenase is a monomeric glycoprotein (pI 4.2) incapable of reducing O₂ to H₂O₂ (> 5 × 10⁴-fold lower rate using a standard pyranose oxidase assay); pyranose 2-dehydrogenase is actively secreted into the extracellular fluid (up to 0.5 U/ml culture filtrate). The dehydrogenase has a native molecular mass of ∼79 kDa as determined by gel filtration; its subunit molecular mass is ∼75 kDa as estimated by SDS-PAGE. Two pH optima of the enzyme were found, one alkaline at pH 9 (phosphate buffer) and the other acidic at pH 4 (acetate buffer). Ag⁺, Hg²⁺, Cu²⁺, and CN^– (10 mM) were inhibitory, while 50 mM acetate had an activating effect. Received: 19 August 1996 / Accepted: 21 November 1996