Rapid surface plasmon resonance-based inhibition assay of deoxynivalenol

Deoxynivalenol belongs to a group of highly toxic fungal metabolites produced by Fusarium species that may contaminate food and animal feed, mostly grains. Three different monoclonal mouse anti-deoxynivalenol antibodies were compared for the development of a surface plasmon resonance (SPR)-based immunoassay for the selective and quantitative determination of deoxynivalenol in naturally contaminated matrices. A conjugate of deoxynivalenol with the protein casein was prepared and immobilized on the sensor chip surface. An excess of antibody was added to each test solution before the measurement. The assay was based on the competition for antibody binding between the immobilized deoxynivalenol conjugate on the sensor and the free deoxynivalenol molecules in the test solution. The deoxynivalenol-casein sensor could be reused more than 500 times without significant loss of activity using 6 M guanidine chloride solution for regeneration. The cross-reactivity of the three antibodies in the SPR assay was tested with other trichothecene mycotoxins (3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, nivalenol, HT2-toxin, and T2-toxin). The only sample preparation was extraction with max 80 vol % acetonitrile and 10-fold dilution with the running buffer. The assay had an optimal range between 2.5 and 30 ng/mL deoxynivalenol in the test solution. Most results of the SPR-based assay were in agreement with liquid chromatography/tandem mass spectrometry measurements of naturally contaminated wheat samples.     

Characterization of commercial kava-kava herbal drug and herbal drug preparations by means of nuclear magnetic resonance spectroscopy

The efficiency of one- and two-dimensional NMR experiments in characterizing the content of the constituents of both herbal drugs and herbal drug preparations is demonstrated for kava-kava. These experiments directly detect active constituents represented by kavalactones in both a finely powdered herbal drug and a commercial extract. In addition, NMR spectroscopy can detect all other compounds present in the extract. As previously evidenced, NMR experiments can represent a generally applicable technique for rapid screening and are a complement to the classical analytical techniques such as high-performance thin-layer chromatography, high-performance liquid chromatography, capillary gas chromatography, and electrophoresis. These experiments can be considered a very simple and fast analytical method to obtain a fingerprint of the herbal drugs and their preparations, and to quantify the content of the active principles of the extract.     

Breeding bird response to partially harvested riparian management zones

We compared avian communities among three timber harvesting treatments in 45-m wide even-age riparian management zones (RMZs) placed between upland clearcuts and along one side of first- or second-order streams in northern Minnesota, USA. The RMZs had three treatments: (1) unharvested, (2) intermediate residual basal area (RBA) (targeted goal 11.5 m²/ha, realized 16.0 m²/ha), and (3) low RBA (targeted goal 5.7 m²/ha, realized 8.7 m²/ha). Surveys were conducted one year pre-harvest and three consecutive years post-harvest. There was no change in species richness, diversity, or total abundance associated with harvest but there were shifts in the types of birds within the community. In particular, White-throated Sparrows (Zonotrichia albicollis) and Chestnut-sided Warblers (Dendroica pensylvanica) increased while Ovenbirds (Seiurus aurocapilla) and Red-eyed Vireos (Vireo olivaceus) decreased. The decline of avian species associated with mature forest in the partially harvested treatments relative to controls indicates that maintaining an unharvested RMZ adjacent to an upland harvest may aid in maintaining avian species associated mature forest in Minnesota for at least three years post-harvest. However, our observations do not reflect reproductive success, which is an area for future research.     

Effects of liming on chemical properties of soil, needle nutrients and growth of Scots pine transplants

The effects of limestone (2.0 and 4.0 Mg ha⁻¹) on chemical properties of soil, nutrient concentrations of needles and growth of Scots pine (Pinus sylvestris L.) transplants were investigated on three reforestation areas on infertile acidic sites in southern Finland. The limestone was applied either on the soil surface (unploughed plots) or was mixed into the topsoil (ploughed plots). All the treatments were replicated four times. Surface broadcast of lime elevated the pH in the organic layer and in the 0-10 cm layer of mineral soil. The increase in the pH of the organic layer after 21 years was, on average, 0.7 and 1.1 pH units, with a dose of lime 2 and 4 Mg ha⁻¹, respectively. On the ploughed plots, the pH in the uppermost 0-10 cm soil layer was 0.4-0.5 units higher than on the corresponding unlimed plots. Both doses of lime significantly increased the amount of exchangeable Ca and the base saturation (BS) in the topsoil on the ploughed plots, and the amount of exchangeable Ca and Mg, as well as the base saturation (BS) in the organic layer + the 0-10 cm layer of mineral soil on the unploughed plots. Regardless of the techniques used for application of lime, after 21 growing seasons the Ca and Mg concentrations in needles were significantly higher on the limed plots than on the controls. In needles, the Ca/Mn ratio was the best indicator for measuring the response to liming. Only on the unploughed plots did liming increase stand volume and dominant diameter of pines. Intensive disc ploughing produced significantly more stems and increased both stand volume and the dominant height of pines compared to unploughed plots.     

Effects of grassland abandonment, restoration and management on butterflies and vascular plants

When semi-natural pastures are abandoned, specialized grassland species are lost as a consequence of succession. As a counter-measure, previously abandoned grasslands may be restored by clearing shrubs and trees and re-introducing grazing livestock. In order to examine the effects of this type of habitat restoration, we compared species richness of plants and of specialized plants thought to be dependent on continuous management and species richness and abundance of butterflies and red-listed butterflies in 12 sets of matched continuously managed, abandoned and restored grassland in southern Sweden. We found no differences in species richness or abundance between the three grassland types. There were, however, some negative effects of abandonment. The number of management-dependent plants decreased with increasing cover of trees and shrubs, and in restored sites species richness of all groups decreased with increasing cover of trees and shrubs before restoration. Also the present management significantly affected both butterflies and plants. Species richness of both groups increased with increasing vegetation height and differed between sites depending on the species of grazers, with negative effects of sheep compared to cattle or horses. Our study indicates that for grassland management to be efficient, the restoration actions should mainly be directed towards sites where the post-abandonment succession has not proceeded too far.     

Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of the organophosphorus pesticide parathion-methyl

A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the detection of parathion-methyl (PM) was developed and optimized. Fluorescein-labeled PM derivatives (tracers) with different structures were synthesized and purified by thin-layer chromatography. The influence of immunogen and tracer structures on the assay characteristics was investigated. PM concentration determinable by the FPIA ranged from 25 to 10000 ppb. The detection limit was 15 ppb. Methanol extracts of vegetable, fruit, and soil samples were diluted 1/10 for the analysis. Recovery in spiked samples averaged between 85 and 110%. The method developed is characterized by high specificity and reproducibility (CV ranged from 1.5 to 9.1% for interassay and from 1.8 to 14.1% for intra-assay). The FPIA method can be applied to the screening of food and environmental samples for PM residues without complicated cleanup.