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  • 1
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Some of the parameters affecting the staining of keratinized oral epithelium with the zinc iodide-osmium reaction were examined using light and electron microscopy and electron probe microanalysis. Factors examined were block size, incubation temperature and the effect of aldehyde prefixation. Large blocks (4 mm cube) were subdivided after incubation and the staining of the centre and edge compared. Generally the reaction was more variable at the edge than in the centre. Small blocks (1 mm cube) showed a more intense reaction when incubated at 24°C than at 4°C. In all these preparations, final reaction product was seen over Golgi systems, lysosome-like bodies, membrane-coating granules and, in the more intensely stained regions, over endoplasmic reticulum and nuclear membranes as well. In prefixed material, mitochondria were frequently stained in addition to the other organelles. Energy dispersive analysis showed the reaction product to be similar in all preparations and to contain high levels of zinc and osmium but not iodine.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0730-2312
    Keywords: calbindin-D28k ; 1,25-dihydroxyvitamin D3 ; messenger RNA ; organ culture ; polymerase chain reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Organ culture of 19-day-old chick embryo duodena was utilized to evaluate the mechanism of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3)-dependent calbindin-D28k (CaBP) expression. Duodenal CaBP and 1,25(OH)2D3 receptor (VDR) expression were assessed by Western blot analysis, while CaBP and VDR mRNA levels were determined by Northen blot analysis. In untreated duodena, both VDR protein and mRNA were present, while CaBP protein and mRNA were undetectable. Treatment of cultured duodena with 25 nM 1,25(OH)2D3 resulted in detectable CaBP mRNA after 4 h which continued to increase during a 24 h time period. Under these conditions, localization of [3H-1β]1α,25(OH)2D3 in duodenal chromatin is rapid (≤ 30 min). Thus, the delayed accumulation of detectable CaBP mRNA cannot be explained by slow nuclear binding of 1,25(OH)2D3. The inclusion of 1.6 μM actinomycin D in the organ culture partially inhibited the 1,25(OH)2D3-regulated increase in CaBP mRNA, which implies that there is a transcriptional component involved in the increased CaBP mRNA levels. Similarly, quantitative polymerase chain reaction studies allowed the detection of CaBP pre-mRNA and mRNA sequences 1 h after hormone treatment, suggesting that CaBP gene transcription is initiated rapidly. Treatment of cultures with 36 μM cycloheximide 1 h prior to 1,25(OH)2D3 addition resulted in superinduction of VDR mRNA levels but sharply reduced CaBP steady-state mRNA levels. This dramatic reduction in CaBP mRNA reveals that 1,25(OH)2D3-mediated CaBP expression is dependent on ongoing protein synthesis. Thus, we propose that a labile auxiliary protein or other cofactor, which may or may not be 1,25(OH)2D3-dependent, is necessary for 1,25(OH)2D3-mediated CaBP gene transcription in chick duodena.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2019-08-13
    Description: The importance of macrobenthos in benthic‐pelagic coupling and early diagenesis of organic carbon (OC) has long been recognized but has not been quantified at a regional scale. By using the southern North Sea as an exemplary area we present a modelling attempt to quantify the budget of total organic carbon (TOC) reworked by macrobenthos in seafloor surface sediments. Vertical profiles in sediments collected in the field indicate a significant but nonlinear correlation between TOC and macrobenthic biomass. A mechanistic model is used to resolve the bi‐directional interaction between TOC and macrobenthos. A novelty of this model is that bioturbation is resolved dynamically depending on variations in local food resource and macrobenthic biomass. The model is coupled to 3D hydrodynamic‐biogeochemical simulations to hindcast the mutual dependence between sedimentary TOC and macrobenthos from 1948 to 2015. Agreement with field data reveals a satisfactory model performance. Our simulations show that the preservation of TOC in the North Sea sediments is not only determined by pelagic conditions (hydrodynamic regime and primary production) but also by the vertical distribution of TOC, bioturbation intensity, and the vertical positioning of macrobenthos. Macrobenthos annually ingest 20%–35% and in addition vertically diffuse 11%–22% of the total budget of TOC in the upper‐most 30 cm sediments in the southern North Sea. This result indicates a central role of benthic animals in modulating the OC cycling at the sediment‐water interface of continental margins.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 4
    Publication Date: 2015-06-16
    Description: Background: Interleukin-27 (IL-27) has been described to be highly expressed during the very first days after birth, but secretion of IL-27 by dendritic cells during the course of childhood has not been described.FindingsIn our present study we enrolled children (n = 55) in the range from 1 day of to 18 years of age and asked for a small whole blood sample. The capacity of dendritic cells to produce IL-27 during childhood was measured after whole blood culture with or without inflammatory stimuli. Results support recent findings of high IL-27 levels after birth and lowest levels in adults. Interestingly, we detected an interim peak production level at early adolescence. Conclusion: These data hint to prominent roles of IL-27 at the very start of post-natal life. Furthermore, a link has been given to so far not described immunological events during puberty.
    Electronic ISSN: 1756-0500
    Topics: Biology , Medicine
    Published by BioMed Central
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  • 5
    In:  Supplement to: Meyer, Julia; Kröncke, Ingrid (submitted): Shifts in trait-based and taxonomic south-eastern North Sea macrofauna community structure along a 22-year time-series. PLoS ONE
    Publication Date: 2019-11-13
    Description: Current research revealed distinct changes in ecosystem functions, and thus in ecosystem stability and resilience, caused by changes in community structure and diversity loss. Even if benthic species play an important role in benthic-pelagic coupling e.g. through the remineralization of deposited organic material, the long-term variability of traits and functions is largely unknown. By using abundance and bioturbation potential of macrofauna samples, taken along a transect from the German Bight towards the Dogger Bank annually in May in 1990 and from 1995 to 2017, we analysed the taxonomic and trait-based macrofauna long-term community variability and diversity. Taxonomic and trait-based diversity remained stable over time, while three different regimes were found, characterised by changes in taxonomic and trait-based community structure. Min/max autocorrelation factor analysis revealed climatic variables, nitrite, and epibenthic abundance as most important environmental drivers for taxonomic and trait-based changes.
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 6
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