Habitat management: a tool to modify ecosystem impacts of nitrogen deposition? (1/9)

Atmospheric nitrogen deposition has been shown to affect both the structure and the function of heathland ecosystems. Heathlands are semi-natural habitats and, as such, undergo regular management by mowing or burning. Different forms of management remove more or less nutrients from the system, so habitat management has the potential to mitigate some of the effects of atmospheric deposition. Data from a dynamic vegetation model and two field experiments are presented. The first involves nitrogen addition following different forms of habitat management. The second tests the use of habitat management to promote heathland recovery after a reduction in nitrogen deposition. Both modelling and experimental approaches suggest that plant and microbial response to nitrogen is affected by management. Shoot growth and rates of decomposition were lowest in plots managed using more intensive techniques, including mowing with litter removal and a high temperature burn. Field data also indicate that ecosystem recovery from prolonged elevated inputs of nitrogen may take many years, or even decades, even after the removal of plant and litter nitrogen stores which accompanies the more intensive forms of habitat management.  (+info)

Use of multiplex terminal restriction fragment length polymorphism for rapid and simultaneous analysis of different components of the soil microbial community. (2/9)

A multiplex terminal restriction fragment length polymorphism (M-TRFLP) fingerprinting method was developed and validated for simultaneous analysis of the diversity and community structure of two or more microbial taxa (up to four taxa). The reproducibility and robustness of the method were examined using soil samples collected from different habitats. DNA was PCR amplified separately from soil samples using individual taxon-specific primers for bacteria, archaea, and fungi. The same samples were also subjected to a multiplex PCR with the primers for all three taxa. The terminal restriction fragment length polymorphism profiles generated for the two sets of PCR products were almost identical not only in terms of the presence of peaks but also in terms of the relative peak intensity. The M-TRFLP method was then used to investigate rhizosphere bacterial, fungal, and rhizobial/agrobacterial communities associated with the dwarf shrub Calluna vulgaris growing in either open moorland, a mature pine forest, or a transition zone between these two habitats containing naturally regenerating pine trees. Rhizosphere microbial communities associated with Vaccinium myrtillus collected from the native pine forest were also investigated. In this study, individual PCR products from the three taxa were also pooled before restriction digestion and fragment size analysis. The terminal restriction fragment length polymorphism profiles obtained with PCR products amplified individually and with multiplexed and pooled PCR products were found to be consistent with each other in terms of the number, position, and relative intensity of peaks. The results presented here confirm that M-TRFLP analysis is a highly reproducible and robust molecular tool for simultaneous investigation of multiple taxa, which allows more complete and higher resolution of microbial communities to be obtained more rapidly and economically.  (+info)

Implementation of a model for identifying Essentially Derived Varieties in vegetatively propagated Calluna vulgaris varieties. (3/9)

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'Who's who' in two different flower types of Calluna vulgaris (Ericaceae): morphological and molecular analyses of flower organ identity. (4/9)

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Chemopreventive effects of Calluna vulgaris and Vitis vinifera extracts on UVB-induced skin damage in SKH-1 hairless mice. (5/9)

Solar ultraviolet radiation (UV) is a major cause of non-melanoma skin cancer in humans. Photochemoprevention with natural products represents a simple but very effective strategy in the management of cutaneous neoplasia. The study investigated the protective activity of Calluna vulgaris (Cv) and red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on UVB-induced deleterious effects in SKH-1 mice skin. Forty SKH-1 mice were randomly divided into 4 groups (n=10): control, UVB irradiated, Cv + UVB irradiated, BM+UVB irradiated. Both extracts were applied topically on the skin in a dose of 4 mg/40 mul/cm(2) before UVB exposure - single dose. The effects were evaluated in skin 24 hours after irradiation through the presence of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 levels. The antioxidant activity of BM extract was higher than those of Cv extract as determined using stable free radical DPPH assay and ABTS test. One single dose of UVB generated formation of CPDs (p<0.0001) and sunburn cells (p<0.0002) and increased the cytokine levels in skin (p<0.0001). Twenty hours following irradiation BM extract inhibited UVB-induced sunburn cells (p<0.02) and CPDs formation (p<0.0001). Pretreatment with Cv and BM extracts resulted in significantly reduced levels of IL-6 and TNF-alpha compared with UVB alone (p<0.0001). Our results suggest that BM extracts might be a potential candidate in preventing the damages induced by UV in skin.  (+info)

Calluna vulgaris extract modulates NF-kappaB/ERK signaling pathway and matrix metalloproteinase expression in SKH-1 hairless mice skin exposed to ultraviolet B irradiation. (6/9)

Photochemoprevention with natural products represents a new concept in the attempt to reduce the occurrence of skin cancer. However, the molecular mechanisms caused by ultraviolet light exposure remain still unclear. The aim of the study was to assess the mechanisms involved in the action of a Calluna vulgaris (Cv) extract, administered in single or multiple doses (10 consecutive days), on UVB-induced skin damage in SKH-1 hairless mice. The extract was topically applied 30 min before each UVB exposure in two doses (2.5 and 4 mg total polyphenolic content/40 mul/cm(2)). At 24 hours after the last treatment, total mitogen-activated protein kinase (p44/42MAPkinase, ERK 1/2), nuclear factor-kappaB (phospho-NF-kappaB p65), matrix metalloproteinases (MMP-2, MMP-9) and metalloproteinase inhibitor 1 (TIMP-1) levels were measured in skin using enzyme-linked immunosorbent assay (ELISA). MMP-2 and -9 activities were additionally evaluated by zymography. One topical application of Cv extract reduced the secretion (p<0.004) and inhibited MMP-9 activity UVB-mediated (54% inhibition) via inhibition of NF-kappaB activation (68% inhibition). In multiple UVB exposures, both doses of Cv extract induced the increase of ERK 1/2 level in correlation with activation of NF-kappaB and reduced the secretion (p<0.04) and activation of MMP-9 (62% inhibition). Pretreatment with Cv diminished the MMP-2 protein secretion only in one dose UVB-irradiated group (p<0.0001) and decreased TIMP-1 level (p<0.001). These results demonstrated the dual behavior of Cv extract in skin protection against single versus multiple doses of UVB irradiation.  (+info)

Antimicrobial activity of different Finnish monofloral honeys against human pathogenic bacteria. (7/9)

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Nitrogen deposition reduces plant diversity and alters ecosystem functioning: field-scale evidence from a nationwide survey of UK heathlands. (8/9)

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