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The antioxidant effect of aqueous methanolic herb extracts of Serratula coronata, S. wolffii and S. tinctoria was investigated using both enzyme-dependent and enzyme-independent systems. The extracts displayed concentration-dependent inhibition of lipid peroxidation. Flavonoids and ecdysteroids present in the extracts were evaluated as antioxidant components. The flavonoid-containing fraction of the herb extract of S. coronata was more effective in lipid peroxidation than the ecdysteroid-containing fraction. This paper also reports the isolation of quercetin 3-O-methyl ether, apigenin, luteolin, quercetin, luteolin 4'beta-D-glucoside and quercetin 4'beta-D-glucoside from S. coronata. 相似文献
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The first results of the Hungarian sheep prion protein (PrP) genotyping programme are discussed in this paper. To obtain initial genotype frequency data 10 commercial (Hungarian Merino, German Mutton Merino, Merino Landschaf, German Blackheaded, Suffolk, Texel, Ile de France, Charollais, Lacaune, British Milksheep) and 4 indigenous (Gyimes Racka, Hortobágy Racka, Tsigaja, Cikta) breeds were sampled in 2003 and 2004, and the PrP genotypes were determined by microsequencing analysis with capillary electrophoresis. In all commercial breeds, a higher number of sheep were genotyped in 2005 (3648) and in 2006 (3834) within the breeding programme to increase scrapie resistance, and the estimated frequency data were compared to the initial figures to evaluate the efficiency of selection. The new developments arising from the identification of the so-called 'atypical' scrapie cases are also discussed. 相似文献
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Smith KW Smith PR Furó I Pettersson ET Cain FW Favre L Talbot G 《Journal of agricultural and food chemistry》2007,55(21):8585-8588
The crystallization and recrystallization of fats have a significant impact on the properties and quality of many food products. While crystallization has been the subject of a number of studies using pure triacylglycerols (TAG), recrystallization in similarly pure systems is rarely studied. In this work, perdeuterated tripalmitoylglycerol ( (2)H-PPP) was dissolved in medium chain triacylglycerol oil (MCT) to yield a saturated solution. The solution was heated to cause partial melting of the solid and dissolution of the molten fraction of (2)H-PPP in MCT and was then cooled to the original temperature to induce recrystallization from the supersaturated solution. (2)H NMR was used to monitor the disappearance of (2)H-PPP from the solution and showed that recrystallization occurred in two steps. The first step was rapid, taking place over a few minutes, and accounted for more than two-thirds of the total recrystallization. The second step was much slower, taking place over a remarkably long timescale of hours to days. It is proposed that dissolution occurs from all parts of the crystals, leaving an etched and pitted surface. The first step of crystallization is the infilling of these pits, while the second step is the continued growth on the smoothed crystal faces. 相似文献
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Long polar fimbriae (Lpf) are recently discovered adhesins and increasingly important genetic markers of pathogenic Escherichia coli strains. The presence and genotype diversity of Lpf operons was screened in a collection of 97 Escherichia coli O157 strains representing different pathotypes, isolated from healthy cattle (n = 43) and human patients (n = 54) in several countries. Individual structural genes of Lpf were scanned by PCR, and allelic variants were detected with a recently developed typing scheme. Ninety-five strains carried at least one whole Lpf operon (genes lpfABCD and/or lpfABCDE). The 64 enterohaemorrhagic (EHEC) and 24 enteropathogenic (EPEC) strains all carried two Lpf operons, allele 3 of lpfA1 and allele 2 of lpfA2, a combination characteristic of the O157:H7/NM serotype. Out of the 9 bovine atypical (AT; stx-, eae-) strains, 7 carried one complete Lpf operon, allele 1 of lpfA2. The atypical strains belonged to main phylogenetic groups A and B1, while the EHEC and EPEC strains were from group D. Lpf variants carried by the 72 strains of the Escherichia coli Reference Collection (ECOR) were determined with the same typing scheme. Alleles were detected in 25 strains, of which 6 were found negative for the respective Lpf operons in earlier studies. The marker value of the Lpf allelic combination for the O157:H7/NM serotype was confirmed, and further evidence was given for the presence of at least two different genetic lineages of atypical bovine E. coli O157 strains. 相似文献
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In studies of vegetation dynamics, data points describing the changes are often sparse, because changes were not recognized
in early stages or investigations were part of different projects. The snapshots at hand often leave the nature of the dynamics
unrevealed and only give a rough estimation of the directions of changes. Extrapolation of the dynamics with traditional cellular
automaton modeling is also complicated in such cases, because rules often cannot be deduced from field data for each interaction.
We developed a Bayesian MCMC method, using a discrete time stochastic cellular automaton model to reconstruct vegetation dynamics
between vegetation maps available and provide estimation of vegetation pattern in years not surveyed. Spread capability of
each vegetation type was characterized by a lateral spread parameter and another for establishment from species pool. The
method was applied to a series of three vegetation maps depicting vegetation change at a grassland site following abandonment
of grazing in north-eastern Hungary. The Markov chain explored the missing data space (missing maps) as well as the parameter
space. Transitions by lateral expansion had a greater importance than the appearance of new vegetation types without spatial
constraints at our site. We estimated the trajectory of change for each vegetation type, which bore a considerable non-linear
element in most cases. To our best knowledge, this is the first work that tries to estimate vegetation transition parameters
in a stochastic cellular automaton based on field measurements and provides a tool to reconstruct past dynamics from observed
pattern. 相似文献
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Péter Sály Péter Takács István Kiss Peter Bíró Tibor Erős 《Ecology of Freshwater Fish》2011,20(2):251-262
Abstract – Environmental factors act in a hierarchical manner at multiple spatial scales to influence the organisation of ecological assemblages; however, the relative influence of the different scale‐related factor groups is poorly known. We evaluated the importance of catchment‐scale and site‐scale environmental variables, as well as the spatial context of the sampling sites, in shaping stream fish assemblages in an agriculture‐dominated landscape in Hungary. Beside the variables describing spatial context (principal coordinates of a truncated distance matrix among sites), altogether 60 environmental variables were used to predict variability using a variance‐partitioning procedure in redundancy analysis. Presence–absence‐ and relative abundance‐based data were examined at two assemblage levels (entire assemblage and native assemblage) at 54 stream sites. Incorporation of spatial variables increased largely the total explained variability in case of relative abundance, but not for presence–absence data. Of the environmentally explained variance, catchment‐scale variables (e.g., land cover types, patch density) were relatively more influential for the native assemblage‐level analyses, than for analyses at the entire assemblage level, where site‐scale variables (e.g., altitude, depth) proved to be more influential. In addition, pure catchment‐ and pure site‐scale variables have the primary role in determining fish assemblage patterns, whereas the influence of shared variance and that of site‐scale riparian variables proved to be less important. Our findings demonstrate the importance of incorporating the spatial context of the sampling sites in predicting fish assemblage patterns and the effects of channelisation (dikes) in shaping assemblage–environment relationships in this human‐influenced landscape. 相似文献
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Bényei B Komlósi I Pécsi A Kulcsár M Huzsvai L Barros CW Huszenicza G 《Acta veterinaria Hungarica》2011,59(4):485-495
Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL. 相似文献
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Katalin Berecz István Ragasits Sándor Hoffmann 《Archives of Agronomy and Soil Science》2013,59(5-6):381-388
The protein quality of wheat is closely correlated with its amino composition. Consequently, when conducting a N fertilization experiment, it is important to know how the ratio of essential amino acids determining the nutritional quality, especially that of the most important limiting amino acids of wheat within the increased protein content, works out. The effect of nitrogen fertilizer applied at different times and/or doses (0–200 kg/ha) was investigated on grain protein and amino acid contents and yields of a Hungarian bread wheat variety on a soil type of medium ? status (eutric cambisol) in Western Hungary for three years. 160 kg N/ha was necessary to reach the highest possible crude protein content and the split application of this dose proved to be the most beneficial to the crude protein yield on the three years’ average. Though most of the treatments seemed to be disadvantageous from the point of view of amino acid composition considering the nutritional quality, the amount of essential amino acids, especially that of lysine harvested per hectare showed a considerable increase (up to 28.4%). 相似文献