116 research outputs found

    Organic nitrogen enhances nitrogen nutrition and early growth of Pinus sylvestris seedlings

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    Boreal trees are capable of taking up organic nitrogen (N) as effectively as inorganic N. Depending on the abundance of soil N forms, plants may adjust physiological and morphological traits to optimize N uptake. However, the link between these traits and N uptake in response to soil N sources is poorly understood. We examined Pinus sylvestris L. seedlings' biomass growth and allocation, transpiration and N uptake in response to additions of organic N (the amino acid arginine) or inorganic N (ammonium nitrate). We also monitored in situ soil N fluxes in the pots following an addition of N, using a microdialysis system. Supplying organic N resulted in a stable soil N flux, whereas the inorganic N resulted in a sharp increase of nitrate flux followed by a rapid decline, demonstrating a fluctuating N supply and a risk for loss of nitrate from the growth medium. Seedlings supplied with organic N achieved a greater biomass with a higher N content, thus reaching a higher N recovery compared with those supplied inorganic N. In spite of a higher N concentration in organic N seedlings, root-to-shoot ratio and transpiration per unit leaf area were similar to those of inorganic N seedlings. We conclude that enhanced seedlings' nutrition and growth under the organic N source may be attributed to a stable supply of N, owing to a strong retention rate in the soil medium

    Organic nitrogen enhances nitrogen nutrition and early growth of Pinus sylvestris seedlings

    Get PDF
    Boreal trees are capable of taking up organic nitrogen (N) as effectively as inorganic N. Depending on the abundance of soil N forms, plants may adjust physiological and morphological traits to optimize N uptake. However, the link between these traits and N uptake in response to soil N sources is poorly understood. We examined Pinus sylvestris L. seedlings' biomass growth and allocation, transpiration and N uptake in response to additions of organic N (the amino acid arginine) or inorganic N (ammonium nitrate). We also monitored in situ soil N fluxes in the pots following an addition of N, using a microdialysis system. Supplying organic N resulted in a stable soil N flux, whereas the inorganic N resulted in a sharp increase of nitrate flux followed by a rapid decline, demonstrating a fluctuating N supply and a risk for loss of nitrate from the growth medium. Seedlings supplied with organic N achieved a greater biomass with a higher N content, thus reaching a higher N recovery compared with those supplied inorganic N. In spite of a higher N concentration in organic N seedlings, root-to-shoot ratio and transpiration per unit leaf area were similar to those of inorganic N seedlings. We conclude that enhanced seedlings' nutrition and growth under the organic N source may be attributed to a stable supply of N, owing to a strong retention rate in the soil medium.Peer reviewe

    Comparative evaluation of gene delivery devices in primary cultures of rat hepatic stellate cells and rat myofibroblasts

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    BACKGROUND: The hepatic stellate cell is the primary cell type responsible for the excessive formation and deposition of connective tissue elements during the development of hepatic fibrosis in chronically injured liver. Culturing quiescent hepatic stellate cells on plastic causes spontaneous activation leading to a myofibroblastic phenotype similar to that seen in vivo. This provides a simple model system for studying activation and transdifferentiation of these cells. The introduction of exogenous DNA into these cells is discussed controversially mainly due to the lack of systematic analysis. Therefore, we examined comparatively five nonviral, lipid-mediated gene transfer methods and adenoviral based infection, as potential tools for efficient delivery of DNA to rat hepatic stellate cells and their transdifferentiated counterpart, i.e. myofibroblasts. Transfection conditions were determined using enhanced green fluorescent protein as a reporter expressed under the transcriptional control of the human cytomegalovirus immediate early gene 1 promoter/enhancer. RESULTS: With the use of chemically enhanced transfection methods, the highest relative efficiency was obtained with FuGENEℱ6 gene mediated DNA transfer. Quantitative evaluation of representative transfection experiments by flow cytometry revealed that approximately 6% of the rat hepatic stellate cells were transfected. None of the transfection methods tested was able to mediate gene delivery to rat myofibroblasts. To analyze if rat hepatic stellate cells and myofibroblasts are susceptible to adenoviral infection, we have inserted the transgenic expression cassette into a recombinant adenoviral type 5 genome as replacement for the E1 region. Viral particles of this replication-deficient Ad5-based reporter are able to infect 100% of rat hepatic stellate cells and myofibroblasts, respectively. CONCLUSIONS: Our results indicate that FuGENEℱ6-based methods may be optimized sufficiently to offer a feasible approach for gene transfer into rat hepatic stellate cells. The data further demonstrate that adenoviral mediated transfer is a promising approach for gene delivery to these hepatic cells

    Milk Oligosaccharides From Different Cattle Breeds Influence Growth-Related Characteristics of Intestinal Cells

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    Oligosaccharides are present in human milk (HMO) in large amounts and in a high variety: Among other functions they are considered to influence the gut microbiota and gut maturation in infants. Due to the large volume of milk available bovine milk oligosaccharides (BMO) may be an alternative source of functional ingredients to potentially mimic HMO functions. Thus, we investigated direct effects of bovine milk oligosaccharides (BMO) from different cattle breeds on proliferation, differentiation and apoptosis in transformed (HT-29 and Caco-2) and non-transformed human intestinal cells (HIE cells). We observed a profound growth-inhibition effect induced by all BMO isolates in HT-29, Caco-2, and HIE cells in a dose-dependent manner. The effects varied not only between cell lines, i.e., HT-29 and Caco-2 cells were more sensitive than HIE cells, but also between the cattle breeds. Regarding the induction of differentiation, BMO induced differentiation only in HIE cells without affecting apoptosis. Cell cycle analysis via flow cytometry showed that growth inhibition was associated with a G2/M arrest in all cell lines. Expression levels detected by quantitative real-time RT-PCR revealed that this G2/M arrest was associated with changes in mRNA expression levels of cyclin A and B. Cyclin-dependent kinase inhibitors p21cip1 and p27kip1 and the tumor suppressor p53 were only enhanced in HIE cells necessary for arresting cells in the G2/M phase and induction of differentiation. In HT-29 and Caco-2 cells, a loss of p53 expression failed to induce G2/M associated induction of differentiation. The HIE cell specific differentiation induced by BMO was a result of influencing the phosphorylation states of EGFR (epidermal growth factor receptor) and MAP kinase, i.e., ERK1/2 (extracellular signal-regulated kinase 1/2), p38-α, and Akt2 phosphorylation. These results suggest that BMO inhibited intestinal cell proliferation and altered cell cycle dynamics by affecting corresponding regulator genes and mitogen-activated protein kinase signaling. As the development and maturation of digestive and absorptive processes depends on gut differentiation processes, our in vitro experiments show that breed-specific BMO are natural substances influencing various parameter which may be important in vivo in gastrointestinal development. This, however, needs to be proven in future studies

    Penestragania apicalis (Osborn & Ball, 1898), another invasive Nearctic leafhopper found in Europe: (Hemiptera: Cicadellidae, Iassinae)

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    Penestragania apicalis (Osborn & Ball, 1898), eine weitere invasive nearktische Zikade in Europa gefunden (Hemiptera: Cicadellidae, Iassinae). – Im Jahr 2010 wurde die nearktische Zikadenart Penestragania apicalis (Osb. & Ball) erstmalig in Europa gefunden. Insgesamt sind derzeit 16 Fundorte in Frankreich, der Schweiz, Deutschland und Österreich bekannt; daher ist davon auszugehen, dass die Art bereits seit lĂ€ngerer Zeit fest etabliert und in Europa und vielleicht weltweit weiter verbreitet ist. Wie in Nordamerika lebt sie an Gleditschie (Gleditsia triacanthos L.), ĂŒberwintert im Eistadium und hat eine oder zwei Generation pro Jahr, mit adulten Tieren von mindestens Ende Juni bis Anfang Oktober. Ob in Europa wirtschaftlich relevante SchĂ€den verursacht werden, ist noch unklar.In 2010 the Nearctic leafhopper Penestragania apicalis (Osb. & Ball) was found for the first time in Europe. Altogether there are now 16 known localities in France, Switzerland, Germany and Austria indicating that the species is well es‐ tablished for a rather long period and more widespread in Europe and perhaps worldwide. As in North America it lives on honeylocust (Gleditsia triacanthos L.), overwinters in the egg stage and probably has one or two generations a year, with adults at least from late June until early October. It is yet unclear if it causes relevant damage to the host plant in Europe

    Retrospective analysis of the uptake of active surveillance for low-risk prostate cancer in Zurich, Switzerland

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    OBJECTIVES Active surveillance for low-risk prostate cancer closely monitors patients conservatively instead of the pursuit of active treatment to reduce overtreatment of insignificant disease. Since 2009, active surveillance has been recommended as the primary management option in the European Association of Urology guidelines for low-risk disease. The present study aimed to investigate the use and uptake of active surveillance over 10 years in our certified prostate cancer centre (University Hospital of Zurich) compared with those derived from the cancer registry of the canton of Zurich, Switzerland. MATERIALS AND METHODS We retrospectively identified all men diagnosed with low-risk prostate cancer at our institution and from the cancer registry of the canton of Zurich from 2009 to 2018. The primary treatment of each patient was recorded. Descriptive statistics were used to analyze the use of different treatments in our centre. The results were compared with those derived from the cancer registry. RESULTS A total of 3393 men with low-risk prostate cancer were included in this study (University Hospital of Zurich: n = 262; cancer registry: n = 3131). In the University Hospital of Zurich and cancer registry cohorts, 146 (55.7%) and 502 (16%) men underwent active surveillance, respectively. The proportions of local treatment [115 (43.9%) vs 2220 (71%)] and androgen deprivation therapy [0 (0%) vs 43 (1.4%)] were distinctly lower in the University Hospital of Zurich cohort than in the cancer registry cohort. The uptake of active surveillance over the years was high in the University Hospital of Zurich cohort (35.4% in 2009 and 88.2% in 2018) but only marginal in the cancer registry cohort (12.2% in 2009 and 16.2% in 2018). CONCLUSION Despite clear guideline recommendations, active surveillance for low-risk prostate cancer is still widely underused. Our analysis showed that access to a certified interdisciplinary tumour board significantly increases the use of active surveillance

    Catanionic micelles as a model to mimic biological membranes in the presence of anesthetic alcohols

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    We show here the influence of n-alcohols (C2OH-C8OH) on the solubility behavior of cationic-anionic surfactant mixtures, so-called “catanionics”.Westudied catanionics of different compositions composed of sodium dodecyl sulfate (SDS)/cetyltrimethylammonium bromide (CTAB) and sodium dodecanoate (SDod)/CTAB mixtures. Interestingly, with a molar excess of SDS, long chain n-alcohols (C4OH-C8OH) significantly depress the solubility temperature of the SDS+CTAB catanionic and increase the kinetic stability of the solution. The visual observations of solubility temperatures of catanionics were further confirmed by differential scanning calorimetry (DSC) measurements. For the catanionics a multistep solubilization was observed by DSC, for which the sulfate headgroup is responsible. This was probed by replacing SDS by SDod. A remarkable analogy was found between the influence of the alcohols on the solubility patterns of the catanionic mixtures and on the anesthesia of tadpoles. Possible reasons for this analogy are discussed also in this paper

    Penestragania apicalis (Osborn & Ball,1898),another invasive Nearctic leafhopper found in Europe

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    In 2010 the Nearctic leafhopper Penestragania apicalis (Osb.& Ball) was found for the first time in Europe. Altogether there are now 16 known localities in France, Switzerland, Germany and Austria indicating that the species is well established for a rather long period and more widespread in Europe and perhaps worldwide. As in North America it lives on honeylocust (Gleditsia triacanthos L.), overwinters in the egg stage and probably has one or two generations a year, with adults at least from late June until early October. It is yet unclear if it causes relevant damage to the host plant in Europe
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