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Dragos G. Zaharescu Peter S. Hooda Carmen I. Burghelea Antonio Palanca-Soler 《Ecosystems》2016,19(6):1064-1079
An ecosystem is generally sustained by a set of integrated physical elements forming a functional landscape unit—ecotope, which supplies nutrients, microclimate, and exchanges matter and energy with the wider environment. To better predict environmental change effects on ecosystems, particularly in critically sensitive regions such as high altitudes, it is imperative to recognise how their natural landscape heterogeneity works at different scales to shape habitats and sustain biotic communities prior to major changes. We conducted a comprehensive survey of catchment physical, geological and ecological properties of 380 high-altitude lakes and ponds in the axial Pyrenees at a variety of scales, to formulate and test an integrated model encompassing major flows and interactions that drive lake ecosystems. Three composite drivers encompassed most of the variability in lake catchment characteristics. In order of total percentage of variance explained, they were (i) hydrology/hydrodynamics—responsible for type and discharge of inlets/outlets, and for waterbody size; (ii) bedrock geomorphology, summarising geology, slope and fractal order—all dictating vegetation cover of catchment slope and lake shore, and the presence of aquatic vegetation; and (iii) topography, that is, catchment formation type—driving lakes connectivity, and the presence of summer snow deposits. Although driver (i) appeared to be local, (ii) and (iii) showed gradient changes along altitude and latitude. These three drivers differentiated several lake ecotopes based on their landscape similarities. The three-driver model was successfully tested on a riparian vegetation composition dataset, further illustrating the validity and fundamental nature of the concept. The findings inform on the relative contribution of scale-dependent catchment physical elements to lake ecotope and ecosystem formation in high-altitude lakes, which should be considered in any assessment of potentially major deleterious effects due to environmental/climate change. 相似文献
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V F Dima A Petrovici S V Dima M Petrovici B Burghelea 《Archives roumaines de pathologie expérimentales et de microbiologie》1989,48(3):215-225
Experimental results of the present study evidenced the following aspects: a) the antigen, prepared from type I Escherichia coli purified fimbriae (H. 2946 strain), induced immunity at urinary tract level; b) the immunoprotection induced by oral vaccination with multiple doses of fimbriated antigen produced a significant decrease of acute pyelonephritis in newborn guinea pigs and at the same time, a local protection of the urinary tract; c) the immunoprophylaxis by vaccine prepared from fimbriae represents a preferential solution for urinary tract infections prevention in general and especially in children; d) the frequency distribution differences between "protected" and "non-protected" animals were evaluated by chi-square--test with YATES correction and proved to be statistically significant at probability levels. 相似文献
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Zhichao Pei Henrik Anderson Annica Myrskog Gunnar Dunér Teodor Aastrup 《Analytical biochemistry》2010,398(2):161-210
The performance of immunosensors is highly dependent on the amount of immobilized antibodies and their remaining antigen binding capacity. In this work, a method for immobilization of antibodies on a two-dimensional carboxyl surface has been optimized using quartz crystal microbalance biosensors. We show that successful immobilization is highly dependent on surface pKa, antibody pI, and pH of immobilization buffer. By the use of EDC/sulfo-NHS (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysulfosuccinimide) activation reagents, the effect of the intrinsic surface pKa is avoided and immobilization at very low pH is therefore possible, and this is important for immobilization of acidic proteins. Antigen binding capacity as a function of immobilization pH was studied. In most cases, the antigen binding capacity followed the immobilization response. However, the antigen-to-antibody binding ratio differed between the antibodies investigated, and for one of the antibodies the antigen binding capacity was significantly lower than expected from immobilization in a certain pH range. Tests with anti-Fc and anti-Fab2 antibodies on different antibody surfaces indicated that the orientation of the antibodies on the surface had a profound effect on the antigen binding capacity of the immobilized antibodies. 相似文献
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Kyle R. Ganz Liviu Clime Jeffrey M. Farber Nathalie Corneau Teodor Veres Brent R. Dixon 《Applied and environmental microbiology》2015,81(12):3925-3933
The sensitivity and specificity of current Giardia cyst detection methods for foods are largely determined by the effectiveness of the elution, separation, and concentration methods used. The aim of these methods is to produce a final suspension with an adequate concentration of Giardia cysts for detection and a low concentration of interfering food debris. In the present study, a microfluidic device, which makes use of inertial separation, was designed and fabricated for the separation of Giardia cysts. A cyclical pumping platform and protocol was developed to concentrate 10-ml suspensions down to less than 1 ml. Tests involving Giardia duodenalis cysts and 1.90-μm microbeads in pure suspensions demonstrated the specificity of the microfluidic chip for cysts over smaller nonspecific particles. As the suspension cycled through the chip, a large number of beads were removed (70%) and the majority of the cysts were concentrated (82%). Subsequently, the microfluidic inertial separation chip was integrated into a method for the detection of G. duodenalis cysts from lettuce samples. The method greatly reduced the concentration of background debris in the final suspensions (10-fold reduction) in comparison to that obtained by a conventional method. The method also recovered an average of 68.4% of cysts from 25-g lettuce samples and had a limit of detection (LOD) of 38 cysts. While the recovery of cysts by inertial separation was slightly lower, and the LOD slightly higher, than with the conventional method, the sample analysis time was greatly reduced, as there were far fewer background food particles interfering with the detection of cysts by immunofluorescence microscopy. 相似文献
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Pei Z Saint-Guirons J Käck C Ingemarsson B Aastrup T 《Biosensors & bioelectronics》2012,35(1):200-205
A novel approach to the study of molecular interactions on the surface of mammalian cells using a QCM biosensor was developed. For this study, an epidermoid carcinoma cell line (A-431) and a breast adenocarcinoma cell line (MDA-MB-468) were immobilized onto polystyrene-coated quartz crystals. The binding and dissociation between the lectin Con A and the cells as well as the inhibition of the binding by monosaccharides were monitored in real time and provided an insight into the complex avidic recognition of cell glycoconjugates. The real-time lectin screening of a range of lectins, including Con A, DBA, PNA and UEA-I, enabled the accurate study of the glycosylation changes between cells, such as changes associated with cancer progression and development. Furthermore, the kinetic parameters of the interaction of Con A with MDA-MB-468 cells were studied. This application provides investigators in the field of glycobiology with a novel tool to study cell surface glycosylation and may also have impacts on drug discovery. 相似文献
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A colostral proline-rich polypeptide complex (PRP) consisting of over 30 peptides shows beneficial effects in Alzheimer’s disease (AD) patients when administered in the form of sublinqual tablets called Colostrinin. The aim of the present studies was to investigate whether nanopeptide fragment of PRP (NP) - one of the PRP complex components can affect aggregation of amyloid β (Aβ1-42). The effect of NP on Aβ aggregation was studied using Thioflavin T (ThT) binding, atomic force microscopy, and analyzing circular dichroism spectra. Results presented suggest that NP can directly interact with amyloid beta, inhibit its aggregation and disrupt existing aggregates acting as a β sheet breaker and reduce toxicity induced by aggregated forms of Aβ. 相似文献
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Olaoluwa Okusaga Olesja Muravitskaja Dietmar Fuchs Ayesha Ashraf Sarah Hinman Ina Giegling Annette M. Hartmann Bettina Konte Marion Friedl Jason Schiffman Elliot Hong Gloria Reeves Maureen Groer Robert Dantzer Dan Rujescu Teodor T. Postolache 《PloS one》2014,9(1)