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51.
Kurdowska A  Alden SM  Noble JM  Stevens MD  Carr FK 《Cytokine》2000,12(7):1046-1053
The purpose of this study was to determine if interleukin 8 (IL-8) in complex with alpha2-macroglobulin (alpha-2-M) can be taken up by human alveolar macrophages. First, we demonstrated that human alveolar macrophages have receptors for alpha-2-M but not IL-8. The binding of(125)I-labeled alpha-2-M to the cells was specific and saturable, whereas(125)I-labeled recombinant human IL-8 (rhIL-8) did not bind to macrophages. However,(125)I-rhIL-8-alpha-2-M complexes bound to macrophages, and unlabeled alpha-2-M competed for the binding. We then cultured the cells in the presence of(125)I-rhIL-8-alpha-2-M complexes,(125)I-rhIL-8 alone or buffer for 24 h. Macrophages were lysed, and the released radioactivity measured. IL-8 concentrations in supernatants and cells were also measured using an IL-8 ELISA. When the macrophages were incubated with(125)I-rhIL-8-alpha-2-M complexes there was a significant amount of IL-8 associated with the cells. However, this was not the case when the cells were incubated with(125)I- rhIL-8 alone suggesting that only these complexes were taken-up by human alveolar macrophages. Furthermore, the clearance of complexes was specifically inhibited by a monoclonal antibody against the 515-kDa subunit of the alpha-2-M receptor (alpha-2-MR) but not by an isotopic mouse IgG1. The study shows an important clearance mechanism for IL-8 in the lung.  相似文献   
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Time-resolved resonance Raman spectroscopy is a valuable tool for the study of the dynamics of heme-protein interactions. In particular, the photolysis of a ligand by short laser pulses allows for the examination of the dynamic evolution of heme-protein interactions subsequent to ligand dissociation. To date, such studies have been confined largely to hemoglobins and myoglobins. Here we present the results of the first transient Raman study of a peroxidase. Resonance Raman spectra of horseradish peroxidase were obtained within 10 ns of ligand (CO) photolysis at a variety of pH values. We find that there is only minimal relaxation of the heme pocket of horseradish peroxidase in response to ligand photolysis. This relaxation is pH-dependent and most probably involves the heme vinyl substituents. Such behavior is in sharp contrast to the transient behavior of most hemoglobins and beef heart cytochrome oxidase.  相似文献   
54.
Recent discoveries of abundant fossil footprints from the new Grand Staircase‐Escalante National Monument of southern Utah, have important implications for the spatial and temporal distribution of Mesozoic vertebrates in Triassic and Jurassic time. Since the monument's creation in 1996, fossil footprints have been reported from at least seven formations in the Mesozoic (Triassic‐Cretaceous) within the monument. By far the most significant of these discoveries are sauropod and theropod tracks from the upper part of the Middle Jurassic Entrada Sandstone and a large Apatopus trackway from the Late Triassic Chinle Formation. Tracks in the Entrada Sandstone are found at the same stratigraphic level as those in the Moab megatracksite, and so considerably extend this large ichnological complex. A wide‐gauge sauropod trackway (cf. Brontopodus) from this unit represents the first reported from the Entrada Sandstone, and so is the oldest known from the western United States. This trackway also reveals a tail trace, which is the first reliable record of a sauropod tail trace.  相似文献   
55.
Sphingolipids are ubiquitous components of eukaryotic cells and sphingolipid metabolites, such as the long chain base phosphate (LCB-P), sphingosine 1 phosphate (S1P) and ceramide (Cer) are important regulators of apoptosis in animal cells. This study evaluated the role of LCB-Ps in regulating apoptotic-like programmed cell death (AL-PCD) in plant cells using commercially available S1P as a tool. Arabidopsis cell cultures were exposed to a diverse array of cell death-inducing treatments (including Cer) in the presence of S1P. Rates of AL-PCD and cell survival were recorded using vital stains and morphological markers of AL-PCD. Internal LCB-P levels were altered in suspension cultured cells using inhibitors of sphingosine kinase and changes in rates of death in response to heat stress were evaluated. S1P reduced AL-PCD and promoted cell survival in cells subjected to a range of stresses. Treatments with inhibitors of sphingosine kinase lowered the temperature which induced maximal AL-PCD in cell cultures. The data supports the existence of a sphingolipid rheostat involved in controlling cell fate in Arabidopsis cells and that sphingolipid regulation of cell death may be a shared feature of both animal apoptosis and plant AL-PCD.  相似文献   
56.
The Human Phenotype Ontology (HPO) is widely used in the rare disease community for differential diagnostics, phenotype-driven analysis of next-generation sequence-variation data, and translational research, but a comparable resource has not been available for common disease. Here, we have developed a concept-recognition procedure that analyzes the frequencies of HPO disease annotations as identified in over five million PubMed abstracts by employing an iterative procedure to optimize precision and recall of the identified terms. We derived disease models for 3,145 common human diseases comprising a total of 132,006 HPO annotations. The HPO now comprises over 250,000 phenotypic annotations for over 10,000 rare and common diseases and can be used for examining the phenotypic overlap among common diseases that share risk alleles, as well as between Mendelian diseases and common diseases linked by genomic location. The annotations, as well as the HPO itself, are freely available.  相似文献   
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Phenotypic plasticity is often considered important for invasive plant success, yet relatively few studies have assessed plasticity in both native and invasive populations of the same species. We examined the plastic response to temperature for Bromus tectorum populations collected from similar shrub-steppe environments in the Republics of Armenia and Georgia, where it is native, and along an invasive front in California and Nevada. Plants were grown in growth chambers in either ‘warm’ (30/20 °C, day/night) or ‘cold’ (10/5 °C) conditions. Invasive populations exhibited greater adaptive plasticity than natives for freezing tolerance (as measured by chlorophyll a fluorescence), such that invasive populations grown in the cold treatment exhibited the highest tolerance. Invasive populations also exhibited more rapid seedling emergence in response to warm temperatures compared to native populations. The climatic conditions of population source locations were related to emergence timing for invasive populations and to freezing tolerance across all populations combined. Plasticity in growth-related traits such as biomass, allocation, leaf length, and photosynthesis did not differ between native and invasive populations. Rather, some growth-related traits were very plastic across all populations, which may help to dampen differences in biomass in contrasting environments. Thus, invasive populations were found to be particularly plastic for some important traits such as seedling emergence and freezing tolerance, but plasticity at the species level may also be an important factor in the invasive ability of B. tectorum.  相似文献   
59.
BACKGROUND: Lung adenocarcinoma (LAD) has extreme genetic variation among patients, which is currently not well understood, limiting progress in therapy development and research. LAD intrinsic molecular subtypes are a validated stratification of naturally-occurring gene expression patterns and encompass different functional pathways and patient outcomes. Patients may have incurred different mutations and alterations that led to the different subtypes. We hypothesized that the LAD molecular subtypes co-occur with distinct mutations and alterations in patient tumors. METHODOLOGY/PRINCIPAL FINDINGS: The LAD molecular subtypes (Bronchioid, Magnoid, and Squamoid) were tested for association with gene mutations and DNA copy number alterations using statistical methods and published cohorts (n = 504). A novel validation (n = 116) cohort was assayed and interrogated to confirm subtype-alteration associations. Gene mutation rates (EGFR, KRAS, STK11, TP53), chromosomal instability, regional copy number, and genomewide DNA methylation were significantly different among tumors of the molecular subtypes. Secondary analyses compared subtypes by integrated alterations and patient outcomes. Tumors having integrated alterations in the same gene associated with the subtypes, e.g. mutation, deletion and underexpression of STK11 with Magnoid, and mutation, amplification, and overexpression of EGFR with Bronchioid. The subtypes also associated with tumors having concurrent mutant genes, such as KRAS-STK11 with Magnoid. Patient overall survival, cisplatin plus vinorelbine therapy response and predicted gefitinib sensitivity were significantly different among the subtypes. CONCLUSIONS/ SIGNIFICANCE: The lung adenocarcinoma intrinsic molecular subtypes co-occur with grossly distinct genomic alterations and with patient therapy response. These results advance the understanding of lung adenocarcinoma etiology and nominate patient subgroups for future evaluation of treatment response.  相似文献   
60.
Cooperative hunting is often assumed to be mutualistic, maintained through returns to scale, where, by working together, foragers can gain higher per capita return rates or harvest sizes than they can by hunting alone. We test this hypothesis among Martu hunters and find that cooperation only provides increased returns to poorer hunters while disadvantaging better hunters. Even so, better hunters still cooperate as frequently as poorer hunters. We ask whether better hunters are advantaged in secondary sharing distributions or whether they bias their partner choice to kin or household members. We find that better hunters are not more likely to pair up with kin and they do not gain consumption benefits from acquiring more. They share a greater proportion of their harvest than poorer hunters: no matter how much one produces — better hunter, worse hunter, cooperator, solitary hunter — all eat the same amount in the end. Such a result suggests the hypothesis that cooperation might be a costly signal of commitment to the public interest on the part of better hunters, which generates trust among camp members and facilitates strong social networks, particularly among women, who cooperate more than men. While some foragers may benefit through cooperation from returns to scale or risk reduction, others may benefit more through signaling commitment and generating trust.  相似文献   
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