波兰喀尔巴阡山麓漂白淋溶土中铁锰结核的分布、形态和化学组成研究

Iron and manganese oxides are common components of soils. They frequently occur in nodules constituting important soil sorbents and play a crucial role in a number of chemical reactions in the soil environment. In addition, the oxides are very sensitive to environmental changes (moisture, pH, Eh) constituting important indicators of soil-forming processes and water movement in the landscape. The objectives of the study were: i) to examine the distribution and size of Fe-Mn nodules in Albeluvisols containing a fragipan horizon; ii) to determine the morphology and chemical composition of the nodules, and iii) to estimate the effect of the fragipan horizon on water movement within the soil profile. An investigation was carried out on five soil profiles containing a fragipan horizon and classified as Fragic Albeluvisols within the Carpathian Foothills in Poland. In the Albeluvisols studied, the maximum concentration of Fe-Mn nodules occurred in the horizon lying directly on the fragipan horizon. This suggests that the pan acts as a natural barrier restricting water infiltration and leads to the seasonal development of a perched water table promoting redox processes. The most common are coarse (1--0.5 mm) and medium (0.5--0.25 mm) irregular Fe-Mn nodules showing a gradual boundary and undifferentiated internal fabric. Eluvial horizons contained also larger amounts of round and dense nodules with a sharp boundary, suggesting frequent oxidation and reduction. The fragipan horizon contained mainly irregular and soft nodules, suggesting longer saturation with water during the year. Concentrations of trace elements (Cu, Zn) and P were higher within Fe-Mn nodules than in the surrounding soil materials, showing that iron and manganese oxides adsorbed and immobilised these elements.     

Correction to: “Current-IPM-Fit”: a new proposal for enhanced efficacy labelling of plant protection products

Journal of Plant Diseases and Protection - In the original publication, old version of Table 1 was included by mistake. The correct version of Table 1 is given here.     

The importance of the soil skeleton for plant-available nutrients in sites of the Southern Black Forest,Germany

The skeletal fraction of forest soils in the Southern Black Forest has a cation exchange capacity (CEC) within the same order of magnitude as fine earth. As the base saturation in the skeleton is much higher than in the fine earth, stones provide a physiologically more favourable environment for nutrient uptake by plants. The fact that 70% of the skeleton grains showed adherent rhizomorphae and/or fine roots suggests that this potential is widely used by nutrient-adsorbing tissues. Therefore the ecological importance of this additional and, until now, unconsidered ion pool available to plants is probably higher than what is reflected by simple ion quantities. The effective CEC of the coarse fraction in forest sites with crystalline bedrock is reasonably predictable considering the water vapour adsorption of the 105°C dried skeleton at a suction of pF 4.6 (vapour pressure equilibrium with an oversaturated K₂SO₄ solution). The content of exchangeable base cations in the coarse fraction can be estimated using the content of exchangeable Mg in the fine earth. These stochastic relations are causally plausible. The regressions are a first approach to identify pedo-transfer functions predicting the skeletons nutrient potential with the aid of easily measurable site parameters.     

Seroprevalence of anaplasmosis among cattle in Switzerland in 1998 and 2003: no evidence of an emerging disease

Anaplasma marginale infection in Europe has been limited to the Mediterranean and eastern countries, to Austria and to very sporadic cases in Switzerland. There are no reports of its occurrence in the countries north of Switzerland. A severe outbreak of anaplasmosis in August 2002 in a cattle farm in the canton Grisons, Switzerland, north of the Alps, with more than 300 cattle that had to be culled, came unexpected and gave reason to hypothesize presence of an increased yet undetected prevalence of A. marginale in Switzerland. Randomly selected bovine serum samples collected in 1998 and 2003 were tested using a competitive inhibitory ELISA (cELISA) to test the hypothesis. Our validation of the diagnostic sensitivity and specificity of this test, done in the outbreak herd, yielded 99.2 and 83.3%, respectively, probably underestimating the true specificity. The true seroprevalence of anaplasmosis in Swiss cattle determined by cELISA was likely to be zero with upper 95% confidence limits of 2.49% in the canton Grisons and 1.17% in the rest of Switzerland, respectively, in 1998. For 2003, these estimates were even lower. There was no significant difference in apparent prevalences between 1998 and 2003. In search of a possible reservoir, three chamoises out of 46 free ranging wild ruminants from the Swiss National Park, Grisons, tested positive in the cELISA. This reaction is in accordance with A. marginale or a cross reacting agent such as Anaplasma ovis. From our results we conclude that the hypothesis of an increased prevalence of anaplasmosis in cattle in Switzerland must be rejected.     

Liquid crystalline networks composed of pentagonal, square, and triangular cylinders

T-shaped molecules are designed in such a way that they self-organize into nanoscale liquid crystalline honeycombs based on polygons with any chosen number of sides. One of the phases reported here is a periodic organization of identical pentagonal cylinders; the other one is a structure composed of square-shaped and triangular cylinders in the ratio 2:1. These two different packing motifs represent duals of the same topological class. The generalization of the concept applied here allows the prediction of a whole range of unusual complex liquid crystalline phases.     

Endosomal proteolysis of the Ebola virus glycoprotein is necessary for infection

Ebola virus (EboV) causes rapidly fatal hemorrhagic fever in humans and there is currently no effective treatment. We found that the infection of African green monkey kidney (Vero) cells by vesicular stomatitis viruses bearing the EboV glycoprotein (GP) requires the activity of endosomal cysteine proteases. Using selective protease inhibitors and protease-deficient cell lines, we identified an essential role for cathepsin B (CatB) and an accessory role for cathepsin L (CatL) in EboV GP-dependent entry. Biochemical studies demonstrate that CatB and CatL mediate entry by carrying out proteolysis of the EboV GP subunit GP1 and support a multistep mechanism that explains the relative contributions of these enzymes to infection. CatB and CatB/CatL inhibitors diminish the multiplication of infectious EboV-Zaire in cultured cells and may merit investigation as anti-EboV drugs.