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"Meyer, Ulf"
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Land-use intensity shapes kinetics of extracellular enzymes in rhizosphere soil of agricultural grassland plant species
Aims
The aim of this study was to identify how land-use intensity shapes the kinetic properties of extracellular hydrolytic enzymes (EHEs) in rhizosphere soil among and within plant species representing different i) resource acquisition strategies (exploitative (ex) vs. conservative (co) plant species) and ii) response types to land-use intensification (winner (Wi) vs. loser (Lo), i.e. species that increase in abundance due to land-use intensification vs. species that decrease in abundance).
Methods
The potential enzyme activities (V
max
) and the apparent substrate affinities (K
m
) of β-cellobiohydrolase (CBH), β-glucosidase (BG), xylanase (XYL), N-acetylglucosaminidase (NAG), and phosphomonoesterase (PH) were determined in rhizosphere samples of
Agrimonia eupatoria
(co, Lo)
, Dactylis glomerata
(ex, Wi)
, Lotus corniculatus
(co, Lo)
, Taraxacum sect. Ruderalia
(ex, Wi) and
Trifolium repens
(ex, Wi). Samples (
n
= 37) were taken on six permanent grasslands along a gradient in land-use intensity in central Germany.
Results
Plant species identity and performance of species to land-use intensity are less important for explaining enzyme kinetics than are land-use intensity and associated changes in soil properties (especially organic carbon, pH and C:N ratio) and composition of the surrounding plant community, i.e. the abundance of herbs and plant diversity. However, the rhizosphere of winner species of intensive land-use was characterized by higher K
m
of CBH and two out of the three winners were associated with lower K
m
of PH. Higher V
max
of XYL in the rhizosphere of winner species suggest higher production of hemicellulose-degrading enzymes in rhizospheres of higher land-use intensity.
Conclusions
This study demonstrates that both land-use intensity and to a lower degree the type of plants’ resource acquisition strategy affect EHEs of C-, N-, and P-cycles in the rhizosphere. Rhizospheres of common grassland species are hotspots of hemicellulose, chitin, and organic P degradation but not of cellulose degradation. Further studies should consider variations in the kinetics of EHEs as a function of root orders and soil depths.
Journal Article
Immunomodulatory Effects of Vitamin D on Innate and Adaptive Immune Responses to Streptococcus pneumoniae
Background. Streptococcus pneumoniae forms part of the normal nasopharyngeal flora but can also cause a broad spectrum of inflammatory diseases. Vitamin D has potent effects on human immunity, including induction of antimicrobial peptides and suppression of T-cell proliferation, but its ability to modulate the immune response to pneumococci is unknown. Methods. Monocyte-derived dendritic cells (DCs) were stimulated with pneumococcal peptidoglycan (PGN) in the presence or absence of vitamin D. Expression of maturation markers, cytokines, pattern recognition receptors, and antimicrobial peptides were measured with flow cytometry, enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. Stimulated DCs were cocultured with autologous T-helper cells, and concentrations of T-helper (Th) 1-, Th17-, and regulatory T-cell-related cytokines were measured with enzyme-linked immunosorbent assay. Results. Vitamin D enhanced DC maturation and expression of the migration marker C-C chemokine receptor type 7 (CCR7) in PGN-stimulated cells. It also enhanced expression of key pattern recognition receptors (Toll-like receptor 2, Nucleotide-binding oligomerization domain-containing protein 2 [Nod2]) and induced a synergistic upregulation of the inflammatory mediator IL-1β and the β-defensin Human Beta Defensin 3 (hBD-3). Furthermore, vitamin D skewed the DC-mediated T-helper response to PGN from an inflammatory Th1/Th17 phenotype toward a regulatory T-cell phenotype. Conclusion. Vitamin D modulates key elements of innate immunity while dampening adaptive immune responses in DCs after pneumococcal challenge, which may have implications for prevention and treatment of pneumococcusinduced inflammation.
Journal Article
The world's greenest buildings : promise versus performance in sustainable design
\"The World's Greenest Buildings provides the first way to compare building performance, using cost and energy use data that has been verified by independent third parties and to understand how building performance can be upgraded. The book provides: an overview of the rating systems and shows \"best in class\" building performance in North America, Europe, the Middle East, India, China, Australia and the Asia-Pacific region practical examples of best practices for greening both new and existing buildings, useful for architects and engineers, contractors, building owners and managers, facility professionals, developers, lenders and investors, brokers and appraisers, and everyone charged with managing commercial and institutional buildings a response to the intense need for a practical reference for design professionals, building owners, developers and facility managers on how green buildings actually perform at the highest level, one that takes them step-by-step through many different design solutions. interviews with architects, engineers, building owners and developers and industry experts, to provide added insight into the greening process a complete guide to world-class green building performance primarily for new buildings, including corporate, commercial, educational, governmental and other large building types a welath of exemplary case studies of successful green building projects using actual performance data from which to learn a \"recipe,\" based on others' experiences, for delivering successful green building projects in the various countries profiled\"-- Provided by publisher.
Book
The Antimicrobial Protein Psoriasin (S100A7) Is Upregulated in Atopic Dermatitis and after Experimental Skin Barrier Disruption
The innate defense of the skin against microbial threats is influenced by antimicrobial proteins (AMP). Staphylococcus aureus often colonizes the skin of patients with atopic dermatitis (AD). This was explained by diminished expression of AMP including cathelicidin/LL-37, human β-defensins-2 and -3, and dermcidin. The S100-protein psoriasin is an additional keratinocyte-derived AMP that preferentially kills E. coli. As E. coli infections are not observed in atopic skin we investigated the functional role of psoriasin in AD patients. Immunohistochemistry demonstrated enhanced epidermal psoriasin expression in AD. An up to 1500-fold increase in secreted psoriasin was detected by ELISA in vivo on the surface of AD skin compared to healthy control skin. Surprisingly, tumor necrosis factor-α-enhanced psoriasin release in primary keratinocytes was inhibited by the Th2-cytokines IL-4 and -13, whereas IL-17 and -22 induced psoriasin. Epidermal barrier disruption significantly enhanced psoriasin expression as demonstrated by tape stripping in healthy volunteers. The upregulation of psoriasin in AD maybe induced by the disrupted skin barrier offering a possible explanation why these patients do not suffer from skin infections with E. coli. This indicates that the antimicrobial response in AD is not generally impaired, but greatly differs according to the type of AMP produced by the skin.
Journal Article
Dissolved organic matter characteristics of deciduous and coniferous forests with variable management: different at the source, aligned in the soil
Dissolved organic matter (DOM) is part of the biogeochemical cycles of carbon and nutrients, carries pollutants and drives soil formation. The DOM concentration and properties along the water flow path through forest ecosystems depend on its sampling location and transformation processes. To improve our understanding of the effects of forest management, especially tree species selection and management intensity, on DOM concentrations and properties of samples from different ecosystem fluxes, we studied throughfall, stemflow, litter leachate and mineral soil solution at 26 forest sites in the three regions of the German Biodiversity Exploratories. We covered forest stands with three management categories (coniferous, deciduous age class and unmanaged beech forests). In water samples from these forests, we monitored DOC concentrations over 4 years and characterized the quality of DOM with UV-vis absorption, fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Additionally, we performed incubation-based biodegradation assays. Multivariate statistics revealed strong significant effects of ecosystem fluxes and smaller effects of main tree species on DOM quality. Coniferous forests differed from deciduous forests by showing larger DOC concentrations, more lignin- and protein-like molecules, and fewer tannin-like molecules in throughfall, stemflow, and litter leachate. Cluster analysis of FT-ICR-MS data indicated that DOM compositions, which varied in aboveground samples depending on tree species, become aligned in mineral soil. This alignment of DOM composition along the water flow path in mineral soil is likely caused by microbial production and consumption of DOM in combination with its interaction with the solid phase, producing a characteristic pattern of organic compounds in forest mineral soils. We found similarly pronounced effects of ecosystem fluxes on the biodegradability of DOM, but surprisingly no differences between deciduous and coniferous forests. Forest management intensity, mainly determined by biomass extraction, contribution of species, which are not site-adapted, and deadwood mass, did not influence DOC concentrations, DOM composition and properties significantly.
Journal Article
Focal targeting by human β-defensin 2 disrupts localized virulence factor assembly sites in Enterococcus faecalis
Virulence factor secretion and assembly occurs at spatially restricted foci in some Gram-positive bacteria. Given the essentiality of the general secretion pathway in bacteria and the contribution of virulence factors to disease progression, the foci that coordinate these processes are attractive antimicrobial targets. In this study, we show in Enterococcus faecalis that SecA and Sortase A, required for the attachment of virulence factors to the cell wall, localize to discrete domains near the septum or nascent septal site as the bacteria proceed through the cell cycle. We also demonstrate that cationic human β-defensins interact with E. faecalis at discrete septal foci, and this exposure disrupts sites of localized secretion and sorting. Modification of anionic lipids by multiple peptide resistance factor, a protein that confers antimicrobial peptide resistance by electrostatic repulsion, renders E. faecalis more resistant to killing by defensins and less susceptible to focal targeting by the cationic antimicrobial peptides. These data suggest a paradigm in which focal targeting by antimicrobial peptides is linked to their killing efficiency and to disruption of virulence factor assembly.
Journal Article
Molecular Identification and Expression Analysis of Filaggrin-2, a Member of the S100 Fused-Type Protein Family
Genes of the S100 fused-type protein (SFTP) family are clustered within the epidermal differentiation complex and encode essential components that maintain epithelial homeostasis and barrier functions. Recent genetic studies have shown that mutations within the gene encoding the SFTP filaggrin cause ichthyosis vulgaris and are major predisposing factors for atopic dermatitis. As a vital component of healthy skin, filaggrin is also a precursor of natural moisturizing factors. Here we present the discovery of a member of this family, designated as filaggrin-2 (FLG2) that is expressed in human skin. The FLG2 gene encodes a histidine- and glutamine-rich protein of approximately 248 kDa, which shares common structural features with other SFTP members, in particular filaggrin. We found that FLG2 transcripts are present in skin, thymus, tonsils, stomach, testis and placenta. In cultured primary keratinocytes, FLG2 mRNA expression displayed almost the same kinetics as that of filaggrin following Ca(2+) stimulation, suggesting an important role in molecular regulation of epidermal terminal differentiation. We provide evidences that like filaggrin, FLG2 is initially expressed by upper granular cells, proteolytically processed and deposited in the stratum granulosum and stratum corneum (SC) layers of normal epidermis. Thus, FLG2 and filaggrin may have overlapping and perhaps synergistic roles in the formation of the epidermal barrier, protecting the skin from environmental insults and the escape of moisture by offering precursors of natural moisturizing factors.
Journal Article