Fifty years of change in Central European grassland vegetation: Large losses in species richness and animal-pollinated plants

There is growing concern that biodiversity loss in European agricultural landscapes is having negative effects on functional trait diversity. Long-term studies examining vegetation changes from the period before agricultural industrialisation are however rare. Here, we ask how management intensification and increased nutrient input initiated in the 1950/1960s have altered grassland plant community composition, species diversity and functional trait composition using comprehensive datasets from five floodplain regions (plus one protected reference region) in northern Germany. Sites with available historical relevés and vegetation maps (1950/1960s, 1990s) were resampled in 2008 to facilitate the analysis of a period spanning four to five decades.Plant community composition changed tremendously in all study regions during the 50 year period, which was related to increasing Ellenberg indicator values for nutrient availability. Species richness at the plot-level fell by 30–50% over the period, and losses in functional diversity were equally large. A non-formal comparison with the results from the protected reference study region indicates that the changes may mostly be attributable to local nutrient input rather than to supra-regional climate change. Our results indicate a consistent trend towards much more species-poor communities dominated by mow-tolerant, N-demanding competitive grasses, whereas species with more ruderal strategies, species flowering early in the season and, in particular, insect-pollinated herbs have all decreased. The substantial loss of nectar-producing grassland herbs is likely to have negative effects on the abundance of pollinating insects, with consequences for the grassland animal communities. This highlights the growing need for adequate grassland management schemes with low N input to preserve high-nature-value grassland.     

Preparation and comparative release characteristics of three anthocyanin encapsulation systems

Bilberries (Vaccinium myrtillus L.) and their major polyphenolic constituents, anthocyanins, have preventive activities inter alia against colon cancer and inflammatory bowel diseases. However, anthocyanins are sensitive to environmental conditions; thus their bioavailability in the gastrointestinal tract is an important determinant of their in vivo activity. In the study reported here, the potential benefits of encapsulating an anthocyanin rich bilberry extract (BE) on anthocyanin stability were investigated. Nonencapsulated BE and three different BE loaded microcapsule systems were incubated in simulated gastric fluid (SGF) and fed state simulated intestinal fluid (FeSSIF). After exposure to these media, released anthocyanins were identified and quantified by HPLC with UV/Vis detection. Although a rapid release of anthocyanins was observed within the first 20 min, encapsulation of anthocyanins doubled the amount of available anthocyanins after 150 min of incubation. These results illustrate the ability of encapsulation to inhibit early degradation of anthocyanins in the intestinal system.     

Plant Extracts of Winter Savory, Purple Coneflower, Buckwheat and Black Elder Activate PPAR-γ in COS-1 Cells but do not Lower Blood Glucose in Db/db Mice In vivo

The aim of this study was to investigate possible blood glucose-lowering effects of plant extracts in vivo for which prior to this a peroxisome proliferator-activated receptor-γ activity in vitro was observed. The ability of extracts of winter savory, purple coneflower, buckwheat and black elder to dose-dependently activate peroxisome proliferator-activated receptor-γ was determined in a reporter gene assay in COS-1 cells. For evaluation of glucose-lowering effects in vivo, db/db mice were fed a diet containing either rosiglitazone (0.02 g/kg diet, positive control) or one of the plant extracts (0.1 and 1 g/kg diet) for four weeks. Apart from glucose, insulin, triacylglycerols, non-esterified fatty acids, cholesterol and adiponectin were determined in plasma. All plant extracts showed a dose-dependent peroxisome proliferator-activated receptor-γ-activating effect in vitro. In db/db mice none of the plant extracts exerted glucose-lowering effects at the used dosages compared to rosiglitazone. Non-esterified fatty acids, triacylglycerols, cholesterol, insulin and adiponectin in plasma were not altered by the plant extracts as well. Although dose-dependent peroxisome proliferator-activated receptor-γ activity could be shown in COS-1 cells, the experiments in db/db mice lacked to confirm any anti-diabetic effect of the plant extracts in vivo and emphasizes the importance of verifying cell culture data using an appropriate in vivo model.     

Distribution,structure and function of Nordic eelgrass (Zostera marina) ecosystems: implications for coastal management and conservation

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Effects of treatment with ivabradine and atenolol on reproducibility of echocardiographic indices of left heart size and function in healthy cats

ObjectivesData on reproducibility of echocardiographic indices in cats are commonly derived from studies in healthy, non-treated animals. However, medical treatment may alter reproducibility of such data possibly influencing interpretation of results of clinical trials assessing the effects of drugs on cardiovascular function. The objectives were therefore to investigate the effects of ivabradine and atenolol on reproducibility of echocardiographic indices of left heart function.AnimalsEight healthy cats.MethodsRepeated echocardiographic examinations were performed by two observers in mildly sedated cats at baseline and after four weeks of treatment (Group 1, ivabradine 0.3 mg/kg q12 h PO, n = 4; Group 2, atenolol 6.25 mg/cat q12 h PO, n = 4) in a prospective, double-blind, randomized study. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day intraobserver variability of all echocardiographic indices. Variability was expressed as coefficient of variation (CV) and the absolute value below which the difference between two measurements lay with 95% probability. Effects of treatments on variability were compared using linear mixed effects models ANOVA and Fisher's exact test.ResultsOverall, CVs ranged from 0.5 to 50.6% at baseline, 0.5–45.5% after ivabradine, and 0.5–23.3% after atenolol. Reproducibility of all variables determined did neither improve nor worsen consistently after either treatment although atenolol exhibited a tendency toward higher reliability with none of the CVs exceeding 24% as compared to ivabradine.ConclusionsTreatment of healthy cats with either atenolol or ivabradine had only minor effects on reproducibility of echocardiographic data. Whether these findings can be extrapolated to cats with hypertrophic cardiomyopathy deserves further study.     

The exceptionality of stress response in Magnaporthe oryzae: a set of “salt stress-induced” genes unique to the rice blast fungus

Journal of Plant Diseases and Protection - The ability of pathogens to signal perception and adaptation to environmental changes is an important prerequisite for successful colonization of the host...     

Indicators for assessing anthropogenic impact on urban surface and groundwater

Background, Aim and Scope  Our study focuses on the indication of anthropogenic impacts on the urban surface and groundwater in large cities, demonstrated for the cities of Halle/Saale and Leipzig (Germany). For the study we selected indicator substances such as xenobiotics, trace elements, and stable isotopes which are connected to human activities in urban areas. The xenobiotics reported here are the pharmaceutical carbamacepine, the polycylic musk compounds galaxolide and tonalide, the life style product caffeine, and industrial chemicals such as bisphenol A and t-nonylphenol. The investigated xenobiotics pose largely unknown risks to human health and the aquatic ecosystem. Trace elements are represented by the rare earth element gadolinium (Gd), used as magnetic resonance imaging contrast substance. Nitrogen isotopes in dissolved nitrate characterize the origin of nitrogen compounds, mixing and reaction processes. Methodology  River water was sampled along the flow path of the rivers Saale and Weisse Elster through the city of Halle/Saale, the rivers Luppe and Weisse Elster through the city of Leipzig. Separate samples were collected from the effluent of the local waste water treatment plants. Groundwater from Quaternary plain aquifers along the rivers and from different urban locations was collected at the same time. The indicators were analysed and assessed according to their sources, concentration and distribution patterns. Results and Discussion  Based on the nitrogen isotopic signature, dissolved nitrate in river water of the Saale was referred mainly to two sources: the effluent of the water treatment plant and a mixture of diffusive inputs from rain water channels, sewage leakages and agriculture activities along the rivers. The Gd anomaly was recognized in surface water of both cities, particularly in the effluent of the water treatment plants, but clearly attenuated in groundwater. We measured concentrations of xenobiotics in river and sewer water between 10 and 60,000 ng L⁻¹, and, in groundwater, one order of magnitude lower. Distinctions of xenobiotic patterns were found in river water before and after the effluent of treated waste water into the rivers. Degradation of endocrine disrupters and fragrances, but also persistence of carbamacepine were recognized as essential processes during waste water treatment. At the study site Halle/Saale, mass balances were set up for xenobiotics and water fluxes. Conclusions  At both sites, we demonstrated that indicators such as xenobiotics, gadolinium, and nitrogen isotopes are suitable for assessing anthropogenic impacts on urban water. However, the behaviour of these indicators in surface and groundwater has to be considered according to the different geochemical environments.     

Precipitation of enzymes and organic matter by aluminum—Impacts on carbon mineralization

The precipitation of dissolved organic matter (DOM) by aluminum (Al) results in a stable soil organic matter (OM) fraction. Extracellular enzymes can also be removed from soil solution by sorption or precipitation, but whether this affects their activity and their importance for carbon (C) mineralization is largely unknown. We studied the activity of eight extracellular enzymes, precipitated by Al together with DOM, in relation to C mineralization of the precipitated OM. Dissolved OM was obtained from the Oi and Oa horizon of two forest soils and precipitated at different Al : C ratios and pH values to achieve a large variation in composition and C mineralization of precipitated OM. All eight enzymes were present in a functional state in precipitated OM. On average 53% of DOM was precipitated, containing on average 17%–41% of the enzyme activity (EA) involved in C degradation (chitinase, cellobiohydrolase, β‐glucosidase, glucuronidase, lacasse, and xylosidase) previously present in soil solution. In contrast, on average only 4%–7% of leucine‐aminopeptidase and acid‐phosphatase activity was found in precipitated OM. The EA found in precipitates significantly increased the percentage of C mineralized of precipitated OM, with a stronger influence of C‐degrading enzymes than enzymes involved in N and P cycling. However, after 8 weeks of incubation the correlations between EA and C mineralization disappeared, despite substantial EA being still present and only 0.5%–7.7% of C mineralized. Thus, degradation of precipitated OM seems to be governed by EA during the first degradation phase, but the long‐term stability of precipitated OM is probably related to its chemical properties.     

黄土区几种土壤培养过程中可溶性有机碳、氮含量及特性的变化

对不同地域农田和林地土壤进行35 d好气培养研究,结果表明:不同土壤培养过程中可溶性有机碳(SOC)含量呈明显下降,而可溶性有机氮(SON)含量却呈明显增加趋势。不同农田土壤相比,在培养起始时和培养过程中红油土SOC和SON的平均含量均高于黑垆土和淋溶褐土;同为黑垆土,林地土壤SOC和SON含量均明显高于相应农田土壤。与起始值相比,土壤培养后提取的可溶性有机物的UV280和HIXem(Hu-mification index)值均明显增加,其中HIXem值在培养的第8天和第35天时呈显著增加趋势。随着培养过程的持续,SOC/SON比值逐渐下降。相关分析发现,培养第35天时SOC的减少幅度与UV 280增加比例呈显著正相关;培养第8天时SOC的减少比例与起始HIXem值呈显著负相关。说明UV280和HIXem值可以在一定程度上反映可溶性有机物种类和结构特性的变化。     

Impact of land use on soil organic carbon stocks in the humid tropics of NE Tanzania

The conversion of tropical forests to agricultural land use is considered as a major cause for a decline in soil organic carbon (SOC) stocks. However, the extent and impact of different land uses on SOC stock development is highly uncertain, especially for tropical Africa due to a lack of reliable data. Interactions of SOC with the soil mineral phase can modify the susceptibility of SOC to become mineralized. Pedogenic Fe‐, Al‐oxides and clay potentially affect SOC stabilization in highly weathered soils typically found in the humid tropics. The aim of our study was to determine the impact of different land uses on SOC stock on such soils. For that purpose, 10 pedologically similar, deeply weathered acidic soils (Acrisols, Alisols) in the Eastern Usambara Mountains (Amani Nature Reserve, NE Tanzania) under contrasting land use were sampled to a depth of 100 cm. The calculated mean SOC stocks were 17.5 kg C m^?2, 16.8 kg C m^?2, 16.9 kg C m^?2, and 20.0 kg C m^?2 for the four forests, two tea plantations, three croplands, and one homegarden, respectively. A significant difference in mean SOC stock of 1.3 kg C m^?2 was detected between forest and cropland land use for the 0–10 cm depth increment. No further significant impacts of land use on SOC stocks were observed. All soils have a clearly clay‐dominated texture. They are characterized by high content of pedogenic oxides with 29 to 47 g kg^?1 measured for the topsoils and 36 to 65 g kg^?1 for the subsoils. No positive significant relationship was found between SOC and clay content. Statistically significant positive relationships existed between oxalate‐extractable Fe, Al, and SOC content for cropland soils only. Compared to data published in literature the SOC stocks determined in our study were generally high independent of the established land use. It appears that efficient SOC stabilization mechanisms are counteracting the higher disturbance regime under agricultural land use in these highly weathered tropical soils.