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81.
In Swedish boreal landscapes, the loss of species-rich semi-natural grasslands is largely due to a long history of agricultural abandonment. Large areas historically managed as meadows have become mature coniferous forest. This study focused on the potential biological legacy following a long period of grassland abandonment. The butterfly fauna in clear-cuts which was historically meadows and abandoned long enough to allow a generation of conifers to mature (70-90 years) was compared with clear-cuts which were historically coniferous forest. The results showed that clear-cuts historically managed as meadows were: (i) much richer in individuals, (ii) more species-rich, and (iii) contained many more grassland specialists than clear-cuts with a history as forest, with many of these species threatened in other parts of Europe.The results from our study demonstrate for the first time, to our knowledge, that the legacy of historical land-use in remnant plant communities can affect butterfly diversity in clear-cuts and hence the large-scale dynamics over a timescale of a full tree rotation. The results of this study have implications for forest management practices. Replanting clear-cuts on land that was previously meadows with deciduous trees or allowing the forest to regenerate naturally instead of planting conifers would make it possible to preserve a greater diversity of habitats for butterflies and other organisms.  相似文献   
82.
NaCl is an important contributor to the taste and texture of bread; therefore, it is challenging to reduce NaCl in bread without compromising quality. This study investigated sensory properties of bread with sourdough fermented with Lactobacillus reuteri accumulating glutamate or γ‐aminobutyrate (GABA). Sourdough was fermented with the GABA‐producing L. reuteri 100‐23 and LTH5448 as well as the glutamate‐accumulating L. reuteri 100‐23ΔgadB and TMW1.106. A consumer panel detected significant differences in the taste of bread with 6% addition of sourdough fermented with glutamate‐ or GABA‐producing L. reuteri. Remarkably, this difference was also detected when GABA‐producing L. reuteri 100‐23 was compared with its glutamate‐producing isogenic mutant L. reuteri 100‐23ΔgadB. The intensity of the salty taste of sourdough bread produced with 1% (flour basis) salt was equivalent to the intensity of the salty taste of reference bread produced with 1.5% salt. A trained panel found that sourdough breads (1 or 2% NaCl flour base) had a higher sour and umami taste intensity when compared with reference bread with the same salt content. Bread produced with sourdough fermented with L. reuteri 100‐23ΔgadB consistently had a higher umami taste intensity when compared with other sourdough breads. Neither sourdough addition nor NaCl level influenced bread volume or texture. In conclusion, the use of sourdough fermented with glutamate‐accumulating lactobacilli allowed reduction of NaCl without adverse effects on the taste or other quality attributes of bread.  相似文献   
83.
Parasites with high host specificity maximally depend on their hosts, which should increase the likelihood of coevolution. However, coevolution requires reciprocal selection exerted by the host and the parasite, and thus a considerable level of parasite virulence. In species of the monogenean ectoparasite genus Gyrodactylus consecutive generations are confronted with a single host, which may constrain the evolution of virulence. Transmission, which is often important in the ecology of Gyrodactylus species, may have the opposite effect, but may also lead to the avoidance of coevolutionary arms races. We investigated the potential outcome of coevolution between Gyrodactylus gasterostei Gl?ser, 1974 and its host, the three-spined stickleback (Gasterosteus aculeatus L.) by determining the strength of genotype by genotype (GxG) interactions on two levels: within and between sympatric and allopatric host populations. To do so, we compared the parasite's infection dynamics on laboratory-reared sympatric (Belgian) and allopatric (German) hosts. We found that a parasite line successfully infected a range of sympatric host genotypes (represented by families), while it failed to establish on allopatric hosts. Phylogeographic studies suggest that neutral genetic divergence between the host populations cannot explain this dramatic difference. Provided that this result can be generalised towards other parasite lines, we conclude that coevolution in this host-parasite system is more likely to lead to local adaptation on the population level than to GxG interactions within populations.  相似文献   
84.
85.
The S(+) enantiomer of ketoprofen is predominant in the plasma of pigs after administration of racemic ketoprofen, although the occurrence and extent of R(-)-to-S(+) inversion is uncertain. Plasma concentrations of both enantiomers were measured and percentages of S(+) ketoprofen were calculated at different time points after intravenous and oral dosing of pigs with 1.5mg/kg R(-) ketoprofen. S(+) ketoprofen was formed immediately after administration and concentrations exceeded R(-) concentrations after 1h. Absence of pre-systemic inversion was deduced from the lower S(+) percentages after oral administration. A rapid and increasing inversion, reaching a maximum of about 70%, occurred and appeared to be responsible for the predominance of S(+) ketoprofen in pig plasma after administration of the racemate.  相似文献   
86.
Two monoclonal antibodies (MAbs) conjugated with horseradish peroxidase were used independently in a competitive enzyme immunoassay (cEIA) to detect Brucella specific antibodies in 1120 sera from Brucella-free cattle, 61 from cattle known to be infected with B. abortus, and 207 sera from vaccinated calves. The results were compared to those obtained in the complement fixation test (CFT). The cEIA with both MAbs proved to be more sensitive than the CFT because no false-negative results were obtained. In addition, discrimination between sera from infected and vaccinated animals was more evident.  相似文献   
87.
88.
Since the amendment of the animal welfare law in Germany in April 2006, castration of piglets without anesthesia is only allowed in the first seven days of life. However, neonates are capable of feeling pain and react more sensitive to pain than adults. Accordingly we expect that castration without anesthesia will be unaccepted in Germany in the future as castration without anesthesia will be forbidden in Switzerland from 2009 on. Denmark and The Netherlands strive for an embargo of the castration without anesthesia and Norway is already asking for an elimination of pain during castration. In Switzerland castration under isoflurane-anesthesia is considered to be a good alternative for the castration without anesthesia. Whether isoflurane-anesthesia is able to reduce stress caused by castration adequately or anesthesia, especially anesthetization that often provokes defensive reaction, is stress for the animal itself was tested in the following investigation. To get an objective statement about the stress of the animals, concentrations of epinephrine and norepinephrine were detected before and immediately after castration/fixation with or without anesthesia. Five day old, healthy animals were divided into four groups. Animals of group A (n = 10) were only fixed without anesthesia, animals of group B (n = 10) were fixed and castrated without anesthesia. In group C (n = 10) the animals were only fixed under anesthesia and the animals of group D (n = 11) were fixed and castrated under anesthesia. Norepinephrine-concentrations and epinephrine-concentrations did rise significantly in all piglets handled without anesthesia (group A and B) independently if castrated or only handled. The values of these animals were significantly higher than the values of the anesthetized animals after fixation/castration (group C and D). In contrast the norepinephrine-concentrations and the epinephrine-concentrations of all anesthetized animals (group C and D) were significantly lower after castration than the concentrations before castration. The catecholamine peak did not differ significantly between the groups of anesthetized animals. The significant increase of the catecholamines of the non-anesthetized animals can be explained by the stress caused by fixation and/or castration without anesthesia. Because of the anesthesia the catecholamine-concentration was reduced considerably during the fixation and/or castration. The results show that fixation and/or castration under anesthesia causes no stress for the piglets.  相似文献   
89.
Differentiation of porcine T helper cells is still poorly investigated, partly due to a lack of monoclonal antibodies (mAbs) specific for molecules involved in this process. Recently, we identified a mAb specific for porcine CD27 and showed that CD27 is expressed by all naïve CD8α- T helper cells but divides CD8α+ T helper cells into a CD27+ and a CD27- subset. In the present study, detailed phenotypical and functional analyses of these T-helper cell subpopulations were performed. Naïve CD8α-CD27+ T helper cells predominantly resided in various lymph nodes, whereas higher proportions of CD8α+CD27+ and CD8α+CD27- T helper cells were found in blood, spleen and liver. Both CD8α+CD27+ and CD8α+CD27- T helper cells were capable of producing IFN-γ upon in vitro polyclonal stimulation and antigen-specific restimulation. Experiments with sorted CD8α-CD27+, CD8α+CD27+ and CD8α+CD27- T-helper cell subsets following polyclonal stimulation revealed the lowest proliferative response but the highest ability for IFN-γ and TNF-α production in the CD8α+CD27- subset. Therefore, these cells resembled terminally differentiated effector memory cells as described in human. This was supported by analyses of CCR7 and CD62L expression. CD8α+CD27- T helper cells were mostly CCR7- and had considerably reduced CD62L mRNA levels. In contrast, expression of both homing-receptors was increased on CD8α+CD27+ T helper cells, which also had a proliferation rate similar to naïve CD8α-CD27+ T helper cells and showed intermediate levels of cytokine production. Therefore, similar to human, CD8α+CD27+ T helper cells displayed a phenotype and functional properties of central memory cells.  相似文献   
90.
To gain a more comprehensive knowledge on whether, besides the well-known piperine, other compounds are responsible for the pungent and tingling oral impression imparted by black pepper, an ethanol extract prepared from black pepper (Piper nigrum L.) was screened for its key sensory-active nonvolatiles by application of taste dilution analysis (TDA). Purification of the compounds perceived with the highest sensory impact, followed by LC-MS and 1D/2D NMR experiments as well as synthesis, led to the structure determination of 25 key pungent and tingling phytochemicals, among which the eight amides 1-(octadeca-2E,4E,13Z-trienyl)piperidine, 1-(octadeca-2E,4E,13Z-trienyl)pyrrolidine, (2E,4E,13Z)-N-isobutyl-octadeca-2,4,13-trienamide, 1-(octadeca-2E,4E,12Z-trienoyl)-pyrrolidine, 1-(eicosa-2E,4E,15Z-trienyl)piperidine, 1-(eicosa-2E,4E,15Z-trienyl)pyrrolidine, (2E,4E,15Z)-N-isobutyl-eicosa-2,4,15-trienamide, and 1-(eicosa-2E,4E,14Z-trienoyl)-pyrrolidine were not yet reported in literature. Sensory studies by means of a modified half-tongue test revealed recognition thresholds ranging from 3.0 to 1150.2 nmol/cm2 for pungency and from 520.6 to 2162.1 nmol/cm2 for the tingling orosensation depending on their chemical structure.  相似文献   
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