Comparative genomic hybridization in detection of DNA changes in canine lymphomas

In this study, chromosomal imbalances in tumor tissues (lymphomas) and nucleotide changes in tumor suppressor TP53 were studied in a Bernese Mountain dog bitch and a cross breed bitch. Using comparative genomic hybridization, numerous chromosomal rearrangements were detected, which indicated the heterogeneity in tumor growth: in the cross breed bitch, a deletion on the chromosome 9, and duplications on chromosomes 5, 8 and 17 have been found. In the Bernese Mountain Dog bitch, losses on chromosomes 1, 5, 8, 12, 18, 22, 27, 29 and gains on chromosomes 1, 2, 9, 11, 15, 16, 18, 20, 23, 24, 25, 28, 29, 30, 34, 36, 37 and 38 were identified. With the sequencing of the TP53 gene, one silent mutation, transition A/G at position 138 in exon 5 was detected, without changing the amino acid.     

Nitrogen leaching from grassland ecosystems managed with organic fertilizers at different stocking rates

This study shows the effect of organic fertilizers at different stocking rates, on nitrogen (N) leaching, measured using zero-tension lysimeters under undisturbed grassland soil. The experiment included two organic fertilizer types – cow dung with dung water (D) and slurry (S), both at a range of stocking rates: 0.9 LU (livestock unit) ha^?1, 1.4 LU ha^?1, 2.0 LU ha^?1 (corresponding to 54, 84 and 120 kg N ha^?1, respectively) and a control (C) treatment. In percolated water, the contents of ammonia nitrogen (NH₄⁺–N) and nitrate nitrogen (NO₃^?–N) were studied. The average concentration of NH₄⁺–N ranged from 0.91 to 1.44 mg l^?1 on fertilized plots compared to 0.55 mg l^?1 on the control plot. The average concentration of NO₃^?–N ranged from 5.2 to 9.5 mg l^?1 on fertilized plots compared to 3.2 mg l^?1 on the control plot. The results of this study showed that the use of organic fertilizers at chosen stocking rates influenced N leaching, but the concentration of N did not exceed the limits for drinking water permitted by Czech legislation. Stocking rates at 2.0 LU ha^?1 and below do not result in elevated N concentrations in percolated water that pose environmental threat.     

Physiological response of culture media-grown barley (Hordeum vulgare L.) to titanium oxide nanoparticles

Since the fate of nanoparticles after their release in the environment and their possible transfer in plants and subsequent impacts is still largely unknown, this paper evaluates the potential phytotoxic effects of up to 20% w/w TiO₂ nanoparticles (nTiO₂) on barley cultivated in hydroponics and agar media. The X-ray diffraction analysis confirmed that nTiO₂ powder corresponds to anatase phase. On agar medium only high concentrations of nTiO₂ (10% and 20% w/w) induced significant inhibition of shoot growth. However, hydroponics treatment with nTiO₂ up to 1000?mg?L^?1 did not show any adverse effect on the shoot growth. In both experiments, (i) root growth inhibition effects became visible with increasing concentration of nTiO₂, (ii) plants treated with nTiO₂ showed no change in chlorophyll a and b content, even though the plants absorbed nTiO₂, (iii) weight of biomass treated with nTiO₂ was not significantly different compared to control. Therefore, we assume that transport of nTiO₂ into the aerial parts is limited due to the presence of effective mechanical or physiological barriers in roots. Overall, it appears that early root growth is a relevant indicator of potential effects of nTiO₂ exposure. Our results also indicate that synthesized nTiO₂ are not significantly toxic to the barley when applied at the concentrations used in this work, even though plants absorb titanium.     

Effect of NO3 and NH4 concentrations in nutrient solution on yield and nitrate concentration in seasonally grown leaf lettuce

The effect of suboptimal supply of nitrogen (N) and of replacing nitrate in the nutrient solution with ammonia on growth, yield, and nitrate concentration in green and red leaf lettuce was evaluated over two seasons (autumn and spring) using multiple regression analysis. The plants were grown in a greenhouse on a Nutrient Film Technique (NFT) system. Nitrogen concentrations in the nutrient solution were either 3?mM or 12?mM, and the form of N was varied as follows: 100% NO₃, 50% NO₃?+?50% NH₄, and 100% NH₄. In both seasons, the biomass (fresh weight) of lettuce heads increased with increasing NO₃ concentrations and in autumn, NO₃ even at 1.5?mM was sufficient for high yield. However, head dry weight was affected neither by the season nor by changes in the composition of the nutrient solution. The concentration of NO₃ had no effect on root dry weight, but it decreased at higher concentrations of NH₄. The number of leaves increased as the ratio of NO₃ to NH₄ in the nutrient solution increased and was higher in autumn because of the longer growth period. Increasing the concentration of NO₃ in nutrient solution increased both total N and nitrate concentration in lettuce heads (dry weight) but decreased the concentration of total C. Also, leaf nitrate concentration was lower in spring than in autumn and decreased with increasing NH₄ concentration. Nitrogen utilization efficiency was maximum when NH₄ levels in the nutrient solution were either 0% or 50% irrespective of the season. Our results thus show that suboptimal N supply in autumn will not affect lettuce yield, and that nitrate concentration in leaves is lower when NH₄ concentrations in nutrient solution are higher and also much lower in red lettuce than in green lettuce.     

Edge effect of low-traffic forest roads on bird communities in secondary production forests in central Europe

Worldwide forests fragmentation has lead to a massive increase of habitat edges, creating both negative and positive impacts on birds. While busy highways dissecting forested areas create edges which are known to reduce bird densities due to the disturbing effect of noise, the impacts of logging forest roads with low traffic volumes have rarely been studied. In this study, we compared species richness and similarity of canopy, cavity and shrub guilds of birds along low-traffic forest roads, in forest interior, and at forest edges in secondary forests in central Europe, where the forests have passed through extensive changes toward uniformly compact growths dominated by production conifers. Although we found tree diversity as positively affecting bird richness across all habitats, the bird richness along forest roads was higher than in forest interior but lower than along forest edges. The shrub guild of birds along forest roads resembled this guild along forest edges while canopy and cavity guilds at the roads were more similar to these guilds in forest interior. Forest interior had the highest probability for some guild to be absent. We conclude that low-traffic roads lead to increase of habitat heterogeneity in structurally poor forests and attract birds due to additional habitat attributes—including better light conditions—that are scarce in forest interior. Therefore, broader support for higher structural diversification of uniform plantations in central European production forests would benefit bird communities inhabiting these areas.     

Short term and long term effects of bibionid (Diptera: Bibionidae) larvae feeding on microbial respiration and alder litter decomposition

Temporal changes of microbial respiration of leaf litter during gut passage by two species of bibionid flies (Penthetria holosericae and Bibio marci) and immediately after defecation were studied as well as the effect of B. marci feeding on microbial respiration in the remaining consumed leaf litter. Respiration in the guts of both species was lower than respiration of the original leaves. Microbial respiration increased after defecation, but respiration was higher in comparison with the original litter only for B. marci. Later, microbial respiration in both species decreased dramatically over several hours. Respiration of the remains of consumed leaves, from which the excrements were removed, was significantly higher than the respiration of non-consumed leaves. Scanning electron microscopy indicated that plant cells in the unconsumed part of the litter were massively broken-up by feeding activity and potentially exposed to microbial colonisation from the surrounding soil and microflora coming from the excrements deposited on the consumed litter. Long term (11 months) exposure of leaf litter and excrements produced from this litter showed that the decomposition of excrements was significantly slower than that of leaves. These findings indicate that bibionid feeding activity causes a short term increase in microbial mineralization of litter, but slows it down in the long term.     

Determination of some phenolic acids in Majorana hortensis by capillary electrophoresis with online electrokinetic preconcentration

An online accumulation/mobilization preconcentration technique based on a dynamic pH junction technique and electrokinetic injection was employed for analysis of phenolic acids (sinapic, ferulic, coumarinic, caffeic, syringic, vanillic, and 4-hydroxybenzoic acid) in extracts from Majorana hortensis leaves. Samples were extracted by pressurized solvent extraction with acetone at 150 degrees C and 15 MPa. The capillary electrophoretic method employed 50 mmol.L (-1) sodium borate, pH 9.5, as the sample electrolyte, 50 mmol.L (-1) sodium phosphate, pH 2.5, as the background electrolyte, and 50 mmol.L (-1) sodium phosphate, pH 2.5, with 60 mmol.L (-1) sodium dodecyl sulfate as the mobilization electrolyte. The method allowed 720-fold to 5560-fold preconcentration of the phenolic acids during 30 min of electrokinetic accumulation with detection limits from 0.38 to 4.22 ng.mL (-1).     

Soil organic matter quality and microbial activities in spruce swamp forests affected by drainage and water regime restoration

The effect of spruce swamp forest (SSF) drainage and water regime restoration on soil organic matter (SOM) quality and soil microbial heterotrophic activities was studied in pristine, drained and restored SSF in the Bohemian Forest, Czech Republic. Sequential chemical SOM fractionation using cold and hot water and hot acid was used to separate SOM fractions according to their mobility and potential lability/recalcitrance, and Fourier transform infrared spectra were used for SOM characterization. Soil physicochemical parameters and heterotrophic microbial activities were also determined. Drainage of SSF had significant long‐term effects (more than 50 yr) on plant communities and SOM quality. On drained sites, cover of sphagnum moss and sedge was much smaller than on pristine locations. A greater proportion of recalcitrant compounds and a smaller proportion of labile compounds were found in drained SSF as compared to pristine sites, which first led to an energy limitation and was followed by a decrease in microbial biomass and heterotrophic microbial activities (CO₂ production, methanogenesis and methanotrophy). Restoration resulted in slow progressive changes in the vegetation cover, including the spread of sphagnum mosses, retreat of mosses typical of drier conditions and increased sedge cover compared with drained SSF. Moreover, soil physicochemical parameters (pH and bulk density), hot‐water‐extractable C and methanotrophic activity tended to evolve towards the pristine SSF and seem to be good indicators of the restoration process. No other SOM fractions changed significantly after restoration. Thus, to change significantly overall SOM quality and most microbial heterotrophic activities following restoration, more than 7 yr are required.