Genetic variability and molecular evolution of arabis mosaic virus based on the coat protein gene sequence

Arabis mosaic virus (ArMV) is an important pathogen infecting a wide range of plant species worldwide. In the present study, we carried out exhaustive phylogenetic analyses based on the coat protein (CP) sequence of ArMV isolates originating from different host plants and geographic regions. Maximum-likelihood reconstruction revealed the presence of three distinct, well-supported phylogroups. BaTS analyses indicated that the diversity of ArMV isolates may be correlated with both host plant and geographic origin. Moreover, population genetic analyses showed significant differences in the level of genetic diversity among variants within ArMV that originated from rhubarb plants, as expected by quasispecies. Further analysis revealed that both selection and recombination are shaping the population structure of ArMV. In total 14 groups of residues were detected as coevolving for different amino acid properties.     

Characterization of two distinct Polish isolates of Pepino mosaic virus

In Poland in 2002 and 2005 two different isolates of Pepino mosaic virus signed PepMV-SW and PepMV-PK were obtained. Both isolates were compared on the basis of their symptomatology on a series of plant species. In addition, the isolates were characterized by the nucleotide sequence analysis of the triple gene block, coat protein and a part of the polymerase genes. The studies showed that the Polish isolates differ from each other and belong to two strains. PepMV-SW was highly similar to European isolates, showing extensive sequence identity, ca. 99%. Pairwise comparisons of PepMV-PK with other PepMV isolates from the GenBank database showed that the highest nucleotide sequence identity was with two isolates: Ch2 from Chile and US2 from the USA.     

Scots pine (Pinus sylvestris L.) roots and soil moisture did not affect soil thermal sensitivity

Through their effects on microbial metabolism, temperature and moisture affect the rate of decomposition of soil organic matter. Plant roots play an important role in SOM mineralization and nutrient cycling. There are reports that rhizosphere soil exhibits higher sensitivity to temperature than root-free soil, and this can have implications for how soil CO₂ efflux may be affected in a warmer world. We tested the effects of 1-week incubation under different combinations of temperature (5, 15, 30 ^°C) and moisture (15, 50, 100% WHC) on the respiration rate of soil planted with Scots pine and of unplanted soil. Soil respiration in both soils was the highest at moderate moisture (p < 0.0001) and, increased with temperature (p < 0.0001). There was also marginally significant effect of soil kind on respiration rate (p < 0.055), but the significant interaction of temperature effect with soil kind effect, indicated, that soil respiration of planted soil was higher than unplanted soil only at 5 ^°C (p < 0.05). The soil kind effect was compared also as Q₁₀ coefficients for respiration rate, showing the relative change in microbial activity with increased temperature. However, there was no difference in the thermal sensitivity of soil respiration between planted and unplanted soils (p = 0.99), irrespective of the level of soil moisture. These findings were similar to the latest studies and confirmed, that in various models, being useful tools in studying of soil carbon cycling, there is no need to distinguish between planted and unplanted soil as different soil carbon pools.     

Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants

During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χ_fd), and temperature dependence of magnetic susceptibility. Mineralogical and geochemical analyses included scanning electron microscopy with energy dispersive spectroscopy, microprobe analysis and X-ray diffraction. The TMPs in fly ash from hard coal combustion have the form of typical magnetic spherules with a smooth or corrugated surface as well as a skeletal morphology, composed of iron oxides (magnetite, maghemite, and magnesioferrite) that occurred in the form of incrustation on the surface of mullite, amorphous silica, or aluminosilicate particles. The TMPs observed in fly ash from lignite combustion have a similar morphological form but a different mineralogical composition. Instead of magnetite and magnesioferrite, maghemite and hematite with lower χ values were the prevailing magnetic minerals, which explains the much lower magnetic susceptibility of this kind of ash in comparison with the ash from hard coal combustion, and probably results from the lower temperature of lignite combustion. Morphology and mineralogical composition of TMPs in cement dust is more diverse. The magnetic fraction of cement dust occurs mostly in the form of angular and octahedral grains of a significantly finer granulation (<20 μm); however, spherules are also present. A very characteristic magnetic form for cement dust is calcium ferrite (CaFe₃O₅). The greatest impact on the magnetic susceptibility of cement dust results from iron-bearing additives (often waste materials from other branches of industry), which should be considered the most dangerous to the environment. Stoichiometric analysis of micro-particles confirmed the presence of heavy metals such as Pb, Mn, Cd, and Zn connected with TMPs, which are carriers of magnetic signals in atmospheric dust. Therefore, in some cases, their presence in topsoil when detected by magnetic measurement can be treated as an indicator of inorganic soil contamination.     

Leaf surface sesquiterpene alcohols of the potato (Solanum tuberosum) and their influence on colorado beetle (Leptinotarsa decemlineata Say) feeding

The structures of two previously unknown sesquiterpene alcohols of the potato (Solanum tuberosum) were assigned. The potato alcohols were obtained by steam-distillation, preparative column chromatography, and separation into fractions by HPLC on a silica gel column. The fractions were studied by GC-FID, GC-MS, and NMR spectroscopy. The potato sesquiterpene alcohols were identified as kunzeaol (6-alpha-hydroxygermacra-1(10),4-diene) and ledol. These two compounds were used in feeding tests with larvae and beetles of the Colorado potato beetle (Leptinotarsa decemlineata Say). In a bioassay, kunzeaol was found to act as a feeding attractant for the beetles.     

Applying Chemometrics to Determine Dispersion of Mine Tailing-Affected Sediments from Submarine Tailing Disposal in Bøkfjorden,Northern Norway

Mine tailing management is one of the largest environmental issues related to mining operation. This study uses chemometrics to assess the dispersion of iron mine tailing-affected sediments in Bøkfjorden, Northern Norway. Metal concentrations (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and physico-chemical sediment characteristics (conductivity, organic matter, sulphate, chloride, grain size, CaCO₃, pH) were analysed in seven sediment cores collected in a transect out of the fjord along with two reference cores. Results of hierarchical cluster analysis and principal component analysis allowed to distinguish between mine tailing-affected and non-affected sediments. Non-affected sediments were especially characterised by high levels of organic matter whilst mine tailing-affected sediments varied significantly in sediment characteristics depending on location in the fjord. Crucial parameters to reveal mine tailing-affected sediments varied between the target metal Fe along with metals of Cd and Mn, albeit less significant. Variations in mine tailing-affected sediment characteristics could be attributed to other anthropogenic activities in the fjord. Despite potential disturbances, chemometrics made it possible to identify dispersion of mine tailing-affected sediments to cover the inner and middle parts of the fjord. The study demonstrates the advantage of applying chemometrics on complex fjord systems, which in this case was used to distinguish mine tailing-affected sediments from areas with elevated levels of metals not necessarily related to the mine.     

Synthesis and insect antifeedant activity of precocene derivatives with lactone moiety

Starting from precocenes I and II, four of their derivatives with a lactone moiety were obtained. The compounds have been assessed as antifeedants against several diverse insect species including the storage pests the confused flour beetle (Tribolium confusum Duv., larvae and adults), the granary weevil beetle (Sitophilus granarius L., adults), and the khapra beetle (Trogoderma granarium Ev., larvae) and against the herbivorous pest insects Colorado potato beetle (Leptinotarsa decemlineata Say, adults and larvae) and aphids (Myzus persicae Sulz.). Precocenes, especially precocene II, showed a very strong antifeedant effect against all storage pests and aphids. The introduction of a lactone moiety caused a decrease in antifeedant activity against these species. Both precocenes were moderately active against L. decemlineata adults. The best antifeedants to this species were precocene derivatives, especially iodolactones. The introduction of iodine into a molecule had a great effect on the antifeedant activity of those compounds.     

Ion Equilibrium in the Soil Solution in Long-term Fertilization Experiment on Sandy Soil

In the conditions of long-term experiment carried out in the experimental field of Warsaw Agricultural University - SGGW at _ yczyn, ion concentration in the soil solution were examined as well as the relationships shaped between ions in the soil solution due to long-term diversified mineral and organic fertilization. Soil solution was obtained by the vacuum method and the concentration of particular ions in the soil solution was determined by the ICP method. Mineral and organic fertilization and liming significantly affected chemical composition of the soil solution and the relationships between particular ions in the soil solution. The lowest concentration of ions in the soil solution was observed in the control plots (not fertilized). Mineral and organic fertilization as well as liming caused the increase of ion concentration in the soil solution. In the plots with mineral fertilization alone K + and NH + 4 ions predominated in the cation structure in the soil solution. In the case of liming the share of Ca 2+ ions increased. Independently from the system of fertilization used, CI m and HCO m 3 ions predominated in the anion structure. The application of organic fertilization affected to the highest degree the concentration of aluminium ion in the soil solution significantly limiting the share of this ion in the cation structure.