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61.
Ismael Galván Eduardo Aguilera Francisco Atiénzar Emilio Barba Guillermo Blanco José L. Cantó Verónica Cortés Óscar Frías István Kovács Leandro Meléndez Anders P. Møller Juan S. Monrós Péter L. Pap Rubén Piculo Juan C. Senar David Serrano José L. Tella Csongor I. Vágási Matthias Vögeli Roger Jovani 《Journal of avian biology》2012,43(3):273-279
Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative effects of feather mites on their hosts and others reporting positive or no effects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing‐dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). The overall effect size was only slightly positive (r =0.066). The effect of feather mite abundance explained <10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefit from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefit from the presence of feather mites. 相似文献
62.
C Garmendia A Bernad J A Esteban L Blanco M Salas 《The Journal of biological chemistry》1992,267(4):2594-2599
The bacteriophage phi 29 DNA polymerase, involved both in the protein-primed initiation and elongation steps of the viral DNA replication, displays a very processive 3',5'-exonuclease activity acting preferentially on single-stranded DNA. This exonucleolytic activity showed a marked preference for excision of a mismatched versus a correctly paired 3' terminus. These characteristics enable the phi 29 DNA polymerase to act as a proofreading enzyme. A comparative analysis of the wild-type phi 29 DNA polymerase and a mutant lacking 3',5'-exonuclease activity indicated that a productive coupling between the exonuclease and polymerase activities is necessary to prevent fixation of polymerization errors. Based on these data, the phi 29 DNA polymerase, a model enzyme for protein-primed DNA replication, appears to share the same mechanism for the editing function as that first proposed for T4 DNA polymerase and Escherichia coli DNA polymerase I on the basis of functional and structural studies. 相似文献
63.
PCR identification of durum wheat BAC clones containing genes coding for carotenoid biosynthesis enzymes and their chromosome localization. 总被引:8,自引:0,他引:8
Carotenoids are essential components in all plants. Their accumulation in wheat seed determines the endosperm colour, which is an important quality trait in wheat. In this study, we report the isolation of BAC clones containing genes coding for three different enzymes of the carotenoid biosynthesis pathway: phytoene synthase (PSY), phytoene desaturase (PDS), and zeta-carotene desaturase (ZDS). Primers were designed on the basis of wheat ESTs similar to the sequences of these three genes in other species, and used to screen a BAC library from Triticum turgidum var. durum (2n = 28, genomes AABB). Eight, six, and nine 384-well plates containing at least one positive clone were found for PSY, PDS, and ZDS, respectively. BACs selected for each of these genes were then divided in two groups corresponding to the A and B genomes of tetraploid wheat, based on differences in the length of the PCR amplification products, conformation-sensitive gel electrophoresis (CSGE), or cleavage amplification polymorphisms. Positive clones were then assigned to chromosomes using a set of D genome substitution lines in T. turgidum var. durum 'Langdon'. PSY clones were localized on chromosomes 5A and 5B, PDS on chromosomes 4A and 4B, and ZDS on chromosomes 2A and 2B. The strategies used for the PCR screening of large BAC libraries and for the differentiation of BAC clones from different genomes in a polyploid species are discussed. 相似文献
64.
Sandra Blanco Sabine Dietmann Joana V Flores Shobbir Hussain Claudia Kutter Peter Humphreys Margus Lukk Patrick Lombard Lucas Treps Martyna Popis Stefanie Kellner Sabine M Hölter Lillian Garrett Wolfgang Wurst Lore Becker Thomas Klopstock Helmut Fuchs Valerie Gailus‐Durner Martin Hrabĕ de Angelis Ragnhildur T Káradóttir Mark Helm Jernej Ule Joseph G Gleeson Duncan T Odom Michaela Frye 《The EMBO journal》2014,33(18):2020-2039
65.
Osteoarthritis (OA) is characterized by cartilage degradation. The chondrocyte is the only cell type present in mature cartilage, and it is important in the control of cartilage integrity. The aim of this study was to analyze, by a proteomic approach, the changes that are characteristic of OA chondrocytes, and to identify new OA-related proteins. Chondrocytes were isolated from the cartilage of ten OA patients undergoing joint replacement and ten donors with no history of joint disease. Whole-cell proteins were resolved by 2-DE and stained with SYPRO Ruby. Protein expression patterns of 2-DE gels from OA and normal chondrocyte proteins were analyzed with PDQuest 7.3.1 software. OA-related proteins were identified by MALDI-TOF or MALDI-TOF/TOF MS. The results were validated for ANXA1, GSTO1, GRP78, and HSP90beta in cells by Western blotting and in tissue cartilage by immunohistochemistry. Results showed an average of 700 protein spots that were present in the 2-DE gels. Compared to normal chondrocytes, 19 protein spots were found to be significantly increased in OA cells (ratio OA:N> or =2.0, p<0.05), whereas nine were decreased in OA chondrocytes (ratio OA:N< or =0.5, p<0.05). Three stress response proteins were increased (HSP90beta, GRP78, and GRP94) and three proteins involved in glycolysis were decreased (enolase, glyceraldehyde 3-phosphate dehydrogenase, and fructose biphosphate aldolase). Functionally, almost all proteins could be classified as proteins involved in cellular metabolism (33%), structure (21%), or protein targeting (21%). 相似文献
66.
The heterogeneity of an aspartic acid-containing thermal polymer population has been studied by anion exchange chromatography, amino acid analysis of the resulting fractions and data processing by the principal components method. By using stepwise or continuous gradients of ionic strength both saw-toothed or bell-shaped elution profiles were obtained. This behaviour and the amino acid composition of analyzed fractions suggest a relatively high degree of heterogeneity in the polymer population although less than theoretically expected. This conclusion is compared with the findings reported in proteinoids made by similar procedures. 相似文献
67.
Dendritic cells (DCs) produce cytokines and are susceptible to cytokine-mediated activation. Thus, interaction of resting immature DCs with TLR ligands, for example nucleic acids, or with microbes leads to a cascade of pro-inflammatory cytokines and skewing of T cell responses. Conversely, several cytokines are able to trigger DC activation (maturation) via autocrine, for example TNF and plasmacytoid DCs, and paracrine, for example type I IFN and myeloid DCs, pathways. By controlling DC activation, cytokines regulate immune homeostasis and the balance between tolerance and immunity. The increased production and/or bioavailability of cytokines and associated alterations in DC homeostasis have been implicated in various human inflammatory and autoimmune diseases. Targeting these cytokines with biological agents as already is the case with TNF and IL-1 represents a success of immunology and the coming years will expand the range of cytokines as therapeutic targets in autoinflammatory and autoimmune pathology. 相似文献
68.
69.
Julien Blanco Beatriz Belln Christo Fabricius Fabio de O. Roque Olivier Pays Franois Laurent Herv Fritz Pierre‐Cyril Renaud 《Global Change Biology》2020,26(3):1138-1154
Land‐use changes and the expansion of protected areas (PAs) have amplified the interaction between protected and unprotected areas worldwide. In this context, ‘interface processes' (human–nature and cross‐boundary interactions inside and around PAs) have become central to issues around the conservation of biodiversity and ecosystem services. This scientific literature review aimed to explore current knowledge and research gaps on interface processes regarding terrestrial PAs. At first, 3,515 references related to the topic were extracted through a standardized search on the Web of Science and analyzed with scientometric techniques. Next, a full‐text analysis was conducted on a sample of 240 research papers. A keyword analysis revealed a wide diversity of research topics, from ‘pure' ecology to sociopolitical research. We found a bias in the geographical distribution of research, with half the papers focusing on eight countries. Additionally, we found that the spatial extent of cross‐boundary interactions was rarely assessed, preventing any clear delimitation of PA interactive zones. In the 240 research papers we scanned, we identified 403 processes that were studied. The ecological effects of PAs were well documented and appeared to be positive overall. In contrast, the effects of PAs on local communities were understudied and, according to the literature focusing on these, were very variable according to local contexts. Our findings highlight key research advances on interface processes, especially regarding the ecological outcomes of PAs, the influence of human activities on biodiversity, and PA governance issues. In contrast, main knowledge gaps concern the spatial extent of interactive zones, as well as the interactions between local people and conservation actions and how to promote synergies between them. While the review was limited to terrestrial PAs, its findings allow us to propose research priorities for tackling environmental and socioeconomic challenges in the face of a rapidly changing world. 相似文献
70.