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21.
22.
Erlend B. Nilsen Henrik Brøseth John Odden John D. C. Linnell 《European Journal of Wildlife Research》2012,58(1):325-333
Harvesting large carnivores is often a controversial issue and thus requires a higher precision than other types of recreational harvest. Despite this, management programmes are often initiated based on very limited knowledge about the state of the population and the composition and magnitude of the harvest. Here we analyse patterns of lynx harvest in Norway based on harvest data from 1994 to 2009. We found clear signs of sex-biased harvest rates, with males generally being more at risk. Further, harvest mortality rates increased with age among males but not among females. In general, the degree of quota filling was high, but there was a tendency for decreasing quota filling with increasing quotas. A population reconstruction of the Norwegian lynx population (1994–2004) based on a modified cohort analysis closely tracked the development in the official monitoring data, suggesting that the managers have access to relatively good information about the development of the population, at least at a larger spatial scale. Despite this, the population trajectory showed large temporal variation, and time lags in the management’s decision-making process are a likely cause of the observed patterns in the Norwegian lynx population. 相似文献
23.
Nielsen SY Hjøllund NH Andersen AM Henriksen TB Kantsø B Krogfelt KA Mølbak K 《PloS one》2012,7(2):e31909
Background and Aims
Q fever is a bacterial zoonosis caused by infection with Coxiella burnetii. It is well established that Q fever causes fetal loss in small ruminants. The suspicion has been raised that pregnant women may also experience adverse pregnancy outcome when the infection is acquired or reactivated during pregnancy. The purpose of this study was to assess the potential association between serologic markers of infection with C.burnetii and spontaneous abortion.Methods
A nested case-control study within the Danish National Birth Cohort, a cohort of 100,418 pregnancies recruited from 1996–2002. Women were recruited in first trimester of pregnancy and followed prospectively. Median gestational age at enrolment was 8 weeks (25 and 75 percentiles: 7 weeks; 10 weeks). During pregnancy, a blood sample was collected at gestational week 6–12 and stored in a bio bank. For this study, a case sample of 218 pregnancies was drawn randomly among the pregnancies in the cohort which ended with a miscarriage before 22 gestational weeks, and a reference group of 482 pregnancies was selected in a random fashion among all pregnancies in the cohort. From these pregnancies, serum samples were screened for antibodies against C. burnetii in a commercial enzyme-linked immunosorbent assay (ELISA). Samples that proved IgG or IgM antibody positive were subsequently confirmatory tested by an immunofluorescence (IFA) test.Results
Among cases, 11 (5%) were C. burnetii positive in ELISA of which one was confirmed in the IFA assay compared to 29 (6%) ELISA positive and 3 IFA confirmed in the random sample.Conclusions
We found no evidence of a higher prevalence of C.burnetii antibodies in serum samples from women who later miscarried and the present study does not indicate a major association between Q fever infection and spontaneous abortion in humans. Very early first trimester abortions were, however, not included in the study. 相似文献24.
Males of the predatory mirid bug Macrolophus caliginosus exploit plant volatiles induced by conspecifics as a sexual synomone 总被引:1,自引:0,他引:1
Hamid R. S. Moayeri Ahmad Ashouri Henrik F. Brødsgaard & Annie Enkegaard 《Entomologia Experimentalis et Applicata》2007,123(1):49-55
The olfactory responses of male and female Macrolophus caliginosus Wagner (Heteroptera: Miridae) adults towards volatiles from green bean plants previously exposed to feeding by conspecifics and to direct odours from conspecifics were tested in a Y-tube olfactometer. Female M. caliginosus did not respond to volatiles from plants exposed to mirid feeding or to odours emitted directly by adult mirids. In contrast, male mirid bugs were attracted both to volatiles from plants previously exposed to feeding by conspecific females and to odours emitted by conspecifics only with a marginally significant preference for the former. The gas chromatography-mass spectrometry analysis showed that mirid feeding induced the release of 11 additional compounds as compared to the volatiles emitted from clean plants. Three of these substances (5-ethyl-2(5H)-furanone, Z-3-hexenyl tiglate, and E,E-α-farnesene) were released only after feeding by females. Furthermore, 21 compounds were identified in volatiles emitted directly by mirids, 12 of which were unique to the mirids (i.e., not present in clean plants or plants previously exposed to mirid feeding). The results suggest that female-specific herbivore-induced plant volatiles play a role as mate-finding cues by the male mirids. The ecological implications of the findings are discussed, and the term ‘sexual synomone’ is introduced. 相似文献
25.
Franzyk H Jensen SR Olsen CE Rasmussen JH 《Nucleosides, nucleotides & nucleic acids》2002,21(1):23-43
Two enantiomerically pure hydroxymethyl substituted cyclopentene nucleoside analogues (42 and 53) related to carbovir and neplanocin A, respectively, were prepared from the chiral pool of iridoid glucosides. In addition two saturated hydroxymethylated analogues (44 and 45) were obtained from a protected intermediate. 相似文献
26.
Thurnher Martin; Wagner Ernst; Clausen Henrik; Mechtler Karl; Rusconi Sandro; Dinter Andre; Birnstiel Max L.; Berger Eric G.; Cotten Matt 《Glycobiology》1994,4(4):429-435
The mucin-type carbohydrate Tn cryptantigen (GalNAc1-O-Ser/Thr,where GalNAc is N-acetyl-D-galactosamine) is expressed in manycarcinomas, in haemopoietic disorders including the Tn syndrome,and on human immunodeficiency virus (HIV) coat glycoproteins,but is not expressed on normal, differentiated cells becauseof the expression of a Tn-processing galactosyltransferase.Using Jurkat T leukaemic cells which express high levels ofTn antigen due to deficient Tn galactosylation, we have establishedthe Tn antigen-mediated gene transfer and demonstrate the considerableefficiency of this approach. We used poly(L-lysine) conjugatesof the monoclonal antibody 1E3 directed against the Tn antigento deliver the luciferase and ß-galactosidase reportergenes to Jurkat cells by receptor-mediated endocytosis. Additionof unconjugated 1E3 reduced transfection efficiency in a concentration-dependentmanner and incubation with free GalNAc abolished DNA transfercompletely, indicating that gene delivery is indeed mediatedby the Tn antigen. Pre-treatment of Jurkat cells with Vibriocholerae sialidase, which uncovers additional Tn antigens, resultedin an improvement of gene transfection. Both human and chickenadenovirus particles attached to the DNA/polylysine complexstrongly augmented transgene expression. When the ß-galactosidase(lacZ) gene was delivered to Jurkat cells by Tn-mediated endocytosis,up to 60% of the cells were positive in the cytochemical stainusing 5-bromo-4-chloro-3-indolyl-ß-D-galactopyranoside(X-gal) as a chromogenic substrate. The efficiency of the transferrinreceptor-mediated DNA uptake into Jurkat cells was comparativelylow, although these cells were shown to express considerableamounts of transferrin receptor. We show here that a mucin-typecarbohydrate antigen mediates highly efficient DNA uptake byendocytosis into Jurkat T cells. This method represents a 50-foldimprovement of Jurkat cell transfection efficiency over otherphysical gene transfer techniques. Specific gene delivery toprimary cancer cells exhibiting Tn epitopes may especially bedesirable in immunotherapy protocols. adenovirus endocytosis gene transfer T cell Tn antigen 相似文献
27.
Katarzyna Weclewicz Maria Ekstrm Krister Kristensson Henrik Garoff 《Journal of virology》1998,72(4):2832-2845
In this work we have studied the intracellular localization properties of the Gag and Env proteins of Moloney murine leukemia virus (MLV) and human immunodeficiency virus (HIV) in dorsal root ganglion (DRG) neurons of rat. These neurons form thick bundles of axons, which facilitates protein localization studies by immunofluorescence analyses. When such neuron cultures were infected with recombinant Semliki Forest virus particles carrying the gag genes of either retrovirus, the expressed Gag proteins were localized to both the somatic and the axonal regions of the DRG neurons. In contrast, the Env proteins were confined only to the somatic region. When the Gag and Env proteins were coexpressed, the Gag proteins were also excluded from the axons. This effect of the Env proteins was shown to be dependent on the concentration of the Gag proteins in the neuron and also to be specific for homologous pairs of retrovirus proteins. Therefore, the results suggest that there are specific interactions between the Env and the Gag proteins of MLV and HIV in the DRG neurons. 相似文献
28.
Savinko T Lauerma A Lehtimäki S Gombert M Majuri ML Fyhrquist-Vanni N Dieu-Nosjean MC Kemeny L Wolff H Homey B Alenius H 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(12):8320-8326
Patients with atopic dermatitis (AD) have repeated cutaneous exposure to both environmental allergens and superantigen-producing strains of Staphylococcus aureus. We used a murine model of AD to investigate the role of staphylococcal enterotoxin B (SEB) in the modulation of allergen-induced skin inflammation. Mice were topically exposed to SEB, OVA, a combination of OVA and SEB (OVA/SEB), or PBS. Topical SEB and OVA/SEB exposure induced epidermal accumulation of CD8+ T cells and TCRVbeta8+ cells in contrast to OVA application, which induced a mainly dermal infiltration of CD4+ cells. SEB and OVA/SEB exposure elicited a mixed Th1/Th2-associated cytokine and chemokine expression profile within the skin. Restimulation of lymph node cells from OVA- and OVA/SEB-exposed mice with OVA elicited strong production of IL-13 protein, whereas substantial amounts of IFN-gamma protein were detected after SEB stimulation of cells derived from SEB- or OVA/SEB-exposed mice. Topical SEB treatment elicited vigorous production of SEB-specific IgE and IgG2a Abs and significantly increased the production of OVA-specific IgE and IgG2a Abs. The present study shows that topical exposure to SEB provokes epidermal accumulation of CD8+ T cells, a mixed Th2/Th1 type dermatitis and vigorous production of specific IgE and IgG2a Abs, which can be related to the chronic phase of atopic skin inflammation. 相似文献
29.
30.
At the edges of tropical rain forest fragments, altered abiotic and biotic conditions influence the structure and dynamics
of plant communities. In Neotropical rain forests, palms (Arecaceae) are important floristic and ecological elements. Palms’
responses to edge effects appear to be idiosyncratic and to depend on the level of disturbance at edges. This paper explores
how variation in forest structure at the edges of two old-growth forest fragments in a tropical rain forest in western Ecuador
affects palms of different species, life-forms, and size classes. We investigate (1) how edge effects influence the relative
proportion of palm adults and juveniles, (2) how distance from the forest edge affects palm density and species richness,
(3) how altered forest structure along edges affects palm density. We found that at edges (1) palm communities had a lower
proportion of adults relative to juvenile individuals compared to continuous forests, (2) the density of two species of palms
and the overall species richness of the palm community tended to decrease toward the edges within forest fragments, and, (3)
altered forest structure decreased the density of adult palms. Hence, edge effects on palms were controlled by the degree
of modification of the forest structure, and by species responses to edge-related disturbance. 相似文献