Investigations on long-term persistence of Corynephorus canescens populations in a large restoration area in an alluvial landscape (NW Germany)

Offene Sandvegetation auf Binnendünen zählt zu den am stärksten bedrohten Vegetationstypen Mitteleuropas. Zu den Pionierarten subatlantisch geprägter Sandstandorte gehört das konkurrenzschwache Silbergras (Corynephorus canescens). In Randbereichen von zwei Mäanderschleifen der Hase (Emsland, NW-Deutschland), die früher zum Teil unter intensiver landwirtschaftlicher Nutzung standen, wurden im Rahmen von Restitutionsmaßnahmen Silbergrasfluren (Spergulo vernalis-Corynephoretum canescentis) auf neu geschaffenen, nährstoffarmen Dünenstandorten angesiedelt. Die „Neodünen“ wurden hierzu mit Mahdgut aus einer Leitbildfläche (nahegelegenes Naturschutzgebiet) inokuliert und vorwiegend mit Rindern (selten mit Pferden) extensiv beweidet. Auch zehn Jahre nach den Restitutionsmaßnahmen sind Corynephorus-Horste auf allen einst inokulierten Flächen und in den Altbeständen vorhanden, jedoch kommen sie in unterschiedlicher Vergesellschaftung vor. Nur einmal konnte eine Neuansiedlung von C. canescens auf einer offenen Sandfläche in Flussnähe festgestellt werden. Unterschiede an den Wuchsorten im Offensandanteil, Humusgehalt des Substrates sowie in der Anzahl und Zusammensetzung konkurrierender Pflanzenarten beeinflussen die Vitalität einzelner Corynephorus-Individuen und die Größe ihrer Populationen. Die Horste variieren in Frequenz, Größe, Vitalität und Anzahl ihrer Ausbreitungseinheiten. Die inokulierten Bestände der neu angelegten Dünen unterscheiden sich in diesen Parametern am stärksten von denen der fragmentierten Altdüne und solchen, die sich spontan neu gebildet haben. Die Ergebnisse zeigen, dass die Größe der Horste mit der Anzahl der Blütenstände und damit mit dem Ausbreitungspotenzial von C. canescens korreliert. Die Größe der Horste hängt von den jeweiligen Wuchsbedingungen ab. Eine dauerhafte Etablierung von C. canescens ist von einem komplexen Wirkungsgefüge mehrerer Faktoren abhängig. Über eine erfolgreiche Ausbreitung entscheidet eine möglichst große Phytomasse des Horstes, da diese die Anzahl der Blütenstände und Diasporen positiv beeinflusst. Das längerfristige Bestehen von C. canescens-Populationen ist im Bereich der „Neodünen“ unter den derzeitigen Bedingungen (z. B. Konkurrenz anderer Pflanzenarten, höhere Humus-Akkumulation, Fehlen stärkerer Offenboden-Dynamik) nicht gesichert. Ein höherer Beweidungsdruck sollte eine Re-Dynamisierung fördern.Open sand vegetation on inland dunes is among the most endangered vegetation types of Central Europe. Weakly competitive pioneer species with subatlantic distribution, such as the grey-hair grass (Corynephorus canescens), are the first colonizers. In two restoration areas in the border zone of meanders of the Hase river (Emsland, NW Germany), in part formerly under intensive agricultural management, Corynephorus pioneer vegetation (Spergulo vernalis-Corynephoretum canescentis) has been established by restoration measures. Newly created dune areas (“neodunes”) with low soil-nutrient conditions were created, inoculated and extensively grazed mainly by cattle (seldom horses). Inoculation was implemented by the transfer of mown and raked plant material from a target area (nature reserve area nearby). Ten years after the restoration measures C. canescens is still growing on all inoculated sites of the new dune systems and on old dune fragments, but the plant communities differ. A new settlement of C. canescens was observed on one open sandy site near the river. Differences in coverage of open sand, humus content of substrate as well as number and composition of competing plant species influence the vitality of Corynephorus individuals and the size of their populations. The tufts vary in frequency, size, vitality and number of dispersal units. With regard to these parameters the inoculated newly created dune areas differ significantly from the old dune fragment and the site with new spontaneous settling. The size of the tufts is correlated with the number of inflorescences and dispersal units. Tuft size corre- sponds to current growing conditions. Long-term persistence depends on a complex interacting network of several factors. High individual phytomass guarantees successful dispersal by influencing the numbers of inflorescences and diaspores. Long-term persistence of C. canescens populations in the complex of the new dune systems cannot be ensured under the current conditions (e. g. competition with other plant species, relatively high humus accumulation, lack of stronger dynamics). A higher grazing impact should enhance re-dynamization

Using 13C in cattle hair to trace back the maize level in the feeding regime-A field test.

Sections from cattle hair serve as an isotopic archive-they contain information on the cattle diet from different time periods. We tested the reliability of 13C signatures (δ13C) in cattle tail switch hair to retrospectively trace back the annual dietary proportion of maize of different production systems without having to sample and analyze the feed. Furthermore, we investigated if differences in dietary proportion of maize during summer and winter feeding can be detected in a single tail switch hair by sampling hair only once a year. We sampled hair and obtained information on management and annual composition of diets on 23 cattle farms in northern Germany. Farms differed in dietary proportions of maize, grass and concentrates as well as in grazing regime (year-round grazing, summer grazing, no grazing). We found that the annual mean δ13C values (δ13CY) of two hair sections that contain the isotopic information of summer and winter feeding is a robust indicator for the annual proportion of maize in cattle diet on a farm. The grazing regimes could clearly be distinguished by analyzing seasonal mean δ13C values (δ13CS). We could also demonstrate short term changes in the diet changes by means of δ13CS. We conclude that the method can be used in different cattle production systems to check on dietary proportions of maize for a period of one year before sampling of hair

Flow-cytometric detection of changes in the physiological state of E. coli expressing a heterologous membrane protein during carbon-limited fedbatch cultivation

The key to optimizing productivity during industrial fermentations is the ability to rapidly monitor and interpret the physiological state of single microbial cells in a population and to recognize and characterize different sub-populations. Here, a flow cytometry-based method for the reproducible detection of changes in membrane function and/or structure of recombinant E. coli JM101 (pSPZ3) expressing xylene monooxygenase (XMO), was developed. XMO expression led to compromised but not permeabilized cell membranes. This was deduced from the fact that recombinant cells only stained with ethidium bromide (EB) and not with propidium iodide (PI). During the glucose-limited fedbatch cultivation, an increase from 25% to 95% of EB-stained cells was observed, occurring between 2 and 5 h after induction. Control experiments confirmed that this increase was due to the recombinant protein production and not caused by any possible effects of varying substrate availability, high cell density, plasmid replication or the presence of the inducing agent. We hypothesize that the integration of the recombinant protein into the cell membrane physically disrupted the functionality of the efflux pumps, thus resulting in EB-staining of the recombinant cells. This method enabled us to detect changes in the physiological state of single cells 2-4 h before other indications of partial cell damage, such as unbalanced growth, acetate accumulation and an increased CO(2) production rate, were observed. This method therefore shows promise with respect to the further development of an early-warning system to prevent sudden productivity decreases in processes with recombinant E. coli expressing heterologous membrane proteins

Relationship between δ¹³CY values in cattle hair and annual dietary proportion of maize (% dry matter).

<p>Each point refers to a farm. The letters A-W indicate the farms (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188926#pone.0188926.t001" target="_blank">Table 1</a>). The solid and dotted lines refer to regression line and 95% confidence interval (CI), respectively (RSE = 0.98).</p

Correlation coefficients between δ¹³CY values in cattle hair of each farm and selected parameters of cattle production systems and location of the farms.

<p>Correlation coefficients between δ¹³CY values in cattle hair of each farm and selected parameters of cattle production systems and location of the farms.</p

Box plots of δ¹³CS values of cattle hair sections analyzed for summer and winter of the three grazing regimes.

<p>The box represents the middle 50% of the data (between the 25th and 75th percentiles); the line in the box represents the median, the upper and lower lines represent the extreme values. Circles indicate outliers (>1.5 interquartile range) in the δ¹³CS value distributions within each season of each grazing regime. Annual dietary proportion (%) of maize, grass and concentrates are indicated in the three boxes above each grazing regime.</p

Effects of stepping exergames under stable versus unstable conditions on balance and strength in healthy community-dwelling older adults: A three-armed randomized controlled trial

This non-blinded, three-armed randomized controlled trial aimed at comparing the effects of volitional step training under stable and unstable conditions on balance, mobility and strength adaptations. Fifty-one healthy and active older adults (age = 69.4 ± 5.6 years; BMI = 27.4 ± 4.6, physical activity = 9.2 ± 5.1 h/week) were allocated to either volitional stepping (VOL), volitional stepping under unstable conditions (VOL + US) or a control group (CON) using the minimization method. Participants underwent eight weeks of exergames based step training with three sessions per week. Pre- and Post-testing included reactive balance (postural sway upon perturbation), functional balance (Y-balance test) and mobility (timed up and go test) to compare the effects of both intervention groups. Strength was tested using the heel rise test and isometric leg extension and leg curl assessment to compare transfer effects of the intervention groups. Data of 45 participants was finally analyzed. Adherence was 87 ± 5% in the VOL + US group and 86 ± 6% in the VOL group. No adverse events occurred. Increased reactive balance was observed in VOL + US only (p  0.05). Explosive strength (rate of force development) showed insignificant but medium interaction effects of the leg extensors in favor of VOL + US (p = 0.08, η2p = 0.12, SMD = 0.2). Volitional step training is an appealing and effective training tool to improve functional balance and calf strength in healthy older adults. Unstable volitional stepping seems to be superior in improving reactive balance and functional mobility under dual-task conditions. It appears that the volitional stepping under unstable conditions requires motor skills relevant for preventing falls since it is more tasks specific when compared to volitional stepping under stable conditions

Recorded variables, source and range.

<p>Recorded variables, source and range.</p

Details of the production systems of cattle farms in the survey on a gradient from west to east.

<p>Details of the production systems of cattle farms in the survey on a gradient from west to east.</p