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241.
Using the ecosystem services approach for better planning and conservation of urban green spaces: a Finland case study 总被引:6,自引:0,他引:6
Jari Niemelä Sanna-Riikka Saarela Tarja Söderman Leena Kopperoinen Vesa Yli-Pelkonen Seija Väre D. Johan Kotze 《Biodiversity and Conservation》2010,19(11):3225-3243
Ecosystem services are vital for humans in urban regions. However, urban development poses a great risk for the ability of
ecosystems to provide these services. In this paper we first address the most important ecosystem services in functional urban
regions in Finland. Well accessible and good quality recreational ecosystem services, for example, provided by urban nature,
are an important part of a high-quality living environment and important for public health. Vegetation of urban regions can
have a role in carbon dioxide sequestration and thus in climate change mitigation. For instance, estimates of carbon sinks
can be compared to total CO2 emissions of an urban region, and the municipality can aim at both increasing carbon sinks and decreasing CO2 emissions with proper land-use planning. Large and contiguous core nature areas, smaller green areas and ecological connections
between them are the essence of regional ecological networks and are essential for maintaining interconnected habitats for
species and thus biological diversity. Thus, both local and regional level ecological networks are vital for maintaining ecosystem
services in urban regions. The impacts of climate change coupled with land-use and land cover change will bring serious challenges
for maintaining ecosystem services in urban areas. Although not yet widely used in planning practices, the ecosystem services
approach can provide an opportunity for land-use planning to develop ecologically sustainable urban regions. Currently, information
on ecosystem services of urban regions is lacking and there is a need to improve the knowledge base for land-use planning. 相似文献
242.
Neuropeptide Y modulates the action of vasodilator agents in guinea-pig epicardial coronary arteries
S rgio Gulbenkian Lars Edvinsson Ole Saetrum Opgaard Angela Valen a John Wharton Julia M. Polak 《Regulatory peptides》1992,40(3):351-362
Recently, we have demonstrated that guinea-pig epicardial coronary arteries are supplied by numerous nerve fibres containing neuropeptide Y (NPY) immunoreactivity. However, examination of vasomotor responses revealed that NPY did not elicit a contractile response in these arteries. In contrast, acetylcholine (ACh), calcitonin gene-related peptide (CGRP), substance P and vasoactive intestinal polypeptide (VIP) all relaxed precontracted arteries. In the present study, we have used histochemical, immunohistochemical and in vitro pharmacological techniques, in order to further investigate the possible role of NPY in guinea-pig epicardial coronary arteries. A double-immunofluorescence staining technique revealed that CGRP and substance P were co-localized in nerve fibres distinct from those displaying NPY immunoreactivity. Furthermore, using a method combining immunofluorescence and histochemical techniques, we observed that putative cholinergic nerve fibres (identified by their acetylcholinesterase content) and NPY-immunoreactive nerve fibres are two different nerve populations. An in vitro pharmacological method demonstrated that NPY markedly inhibited the relaxant responses mediated by ACh, VIP, substance P and isoprenaline but had no effect on CGRP. These results suggest that NPY-containing nerves associated with guinea-pig epicardial coronary arteries may be predominantly involved in modulating the action of vasodilator agents. 相似文献
243.
Coagulation factor VIIa (FVIIa) belongs to a family of proteases being part of the stepwise, self-amplifying blood coagulation cascade. To investigate the impact of the mutation Met(298{156})Lys in FVIIa, we replaced the Gly(283{140})-Met(298{156}) loop with the corresponding loop of factor Xa. The resulting variant exhibited increased intrinsic activity, concurrent with maturation of the active site, a less accessible N-terminus, and, interestingly, an altered macromolecular substrate specificity reflected in an increased ability to cleave factor IX (FIX) and a decreased rate of FX activation compared to that of wild-type FVIIa. In complex with tissue factor, activation of FIX, but not of FX, returned to normal. Deconvolution of the loop graft in order to identify important side chain substitutions resulted in the mutant Val(158{21})Asp/Leu(287{144})Thr/Ala(294{152})Ser/Glu(296{154}) Ile/Met(298{156})Lys-FVIIa with almost the same activity and specificity profile. We conclude that a lysine residue in position 298{156} of FVIIa requires a hydrophilic environment to be fully accommodated. This position appears critical for substrate specificity among the proteases of the blood coagulation cascade due to its prominent position in the macromolecular exosite and possibly via its interaction with the corresponding position in the substrate (i.e. FIX or FX). 相似文献
244.
Determination of metformin in plasma by high-performance liquid chromatography after ultrafiltration
Ole Vesterqvist Fizal Nabbie Brian Swanson 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,716(1-2)
A rapid high-performance liquid chromatography (HPLC) method was developed for determination of metformin, an oral antidiabetic agent, in plasma. Sample preparation entailed a 30-min centrifugation of plasma through a micron filter with direct injection of the protein-free ultrafiltrate into an HPLC system consisting of a cation-exchange extraction column (7.5×4.6 mm), a column switching valve, and a cation-exchange analytical column (250×4.6 mm). The eluent was monitored at 232 nm. Metformin was well resolved at a retention time of about 5 min. There was less than 2% loss of metformin during ultrafiltration and good linearity was established from 0.10 to 40 mg/l of metformin hydrochloride. The lower limit of quantitation was about 0.05 mg/l, at which concentration the signal-to-noise was above 10. The intra- and inter-assay coefficients of variation at plasma concentrations of metformin hydrochloride between 0.25 and 25 mg/l were typically 0.8–1.4% and 3.5–6.4%, respectively. This method offers a rapid sample preparation time and achieves excellent sensitivity without resorting to extraction and evaporation techniques. 相似文献
245.
246.
Ole Olsen Rainer Borriss Ortwin Simon Karl Kristian Thomsen 《Molecular & general genetics : MGG》1991,225(2):177-185
Summary Hybrid (1-3,1-4)--glucanase genes were constructed by extension of overlapping segments of the (1-3,1-4)--glucanase genes from Bacillus amyloliquefaciens and B. macerans generated by the polymerase chain reaction (PCR). Four hybrid genes were expressed in Escherichia coli cells. The mature hybrid enzymes contain a 16, 36, 78, or 152 amino acid N-terminal sequence derived from B. amyloliquefaciens (1-3,1-4)--glucanase followed by a C-terminal segment derived from B. macerans (1-3,1-4)--glucanase. Biochemical characterization of parental and hybrid enzymes shows a significant increase in thermostability of three of the hybrid enzymes when exposed to an acidic environment thus combining two important enzyme characteristics within the same molecule. At pH 4.1, 85%-95% of the initial activity was retained after 1 h at 65° C in contrast to 5% and 0% for the parental enzymes from B. amyloliquefaciens and B. macerans. After 60 min incubation at 70° C, pH 6.0, the parental enzymes retained 5% or less of the initial activity whilst one of the hybrids still exhibited 90% of the initial activity. Of the parental enzymes B. macerans (1-3,1-4)--glucanase had the lower specific activity while the hybrid enzymes exhibited specific activities that were 1.5- to 3-fold higher. These experimental results demonstrate that exchange of homologous gene segments from different species may be a useful technique for obtaining new and improved versions of biologically active proteins.Abbreviations AMY
mature form of Bacillus amyloliquefaciens (1-3,1-4)--glucanase;
- MAC
mature form of B. macerans (1-3,1-4)--glucanase
- SUB
mature form of B. subtilis (1-3,1-4)--glucanase
- H(A16-M), H(A36-M), H(A78-M), H(A107-M), H(A152-M)
mature forms of hybrid enzymes having 16, 36, 78, 107, 152 N-terminal amino acids, respectively, derived from AMY with the remaining amino acids derived from MAC 相似文献
247.
Rafael Zárate Johan Memelink Robert van der Heijden Robert Verpoorte 《Biotechnology letters》1999,21(11):997-1002
In vitro propagation of Catharanthus roseus was achieved using nodal explants. Bud induction was best on medium containing 1.0 mg benzyl aminopurine l–1. Hardening of rooted shoots to soil was very successful with 98% survival. Genetically transformed C. roseus plantlets were obtained after bombardment of nodal explants, which were then micropropagated, with DNA coated particles with green fluorescent protein (GFP) or -glucuronidase (GUS) reporter genes. Histological studies showed that the gene insertion method proved effective with many cells and different tissues displaying the reporter gene signals, showing that gene expressions were rather stable. 相似文献
248.
249.
We report the chemical synthesis of Fuc(12)Gal-O(CH2)7CH3 (1) an analog of the natural blood group (O)H disaccharide Fuc(12)Gal-OR. Compound 1 was a good substrate for recombinant blood group B glycosyltransferase (GTB) and was used as a precursor for the enzymatic synthesis of the blood group B analog Gal(3)[Fuc(12)]Gal-O(CH2)7CH3 (2). To probe the mechanism of the GTB reaction, kinetic evaluations were carried out employing compound 1 or the natural acceptor disaccharide Fuc(12)Gal-O(CH2)7CH3 (3) with UDP-Gal and UDP-GalNAc donors. Comparisons of the kinetic constants for alternative donor and acceptor pairs suggest that the GTB mechanism is Theorell-Chance where donor binding precedes acceptor binding. GTB operates with retention of configuration at the anomeric center of the donor. Retaining reactions are thought to occur via a double-displacement mechanism with formation of a glycosyl-enzyme intermediate consistent with the proposed Theorell-Chance mechanism. 相似文献
250.