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1. Predation‐exclusion experiments have highlighted that top‐down control is pervasive in terrestrial communities, but most of these experiments are simplistic in that they only excluded a single group of predators and the effect of removal was evaluated on a few species from the community. The main goal of our study was to experimentally establish the relative effects of ants and birds on the same arthropod assemblage of canopy trees. 2. We conducted 1‐year long manipulative experiments in an organic citrus grove intended to quantify the independent effects of bird and ant predators on the abundance of arthropods. Birds were excluded with plastic nets whereas ants were excluded with sticky barriers on the trunks. The sticky barrier also excluded other ground dwelling insects, like the European earwig Forficula auricularia L. 3. Both the exclusion of ants and birds affected the arthropod community of the citrus canopies, but the exclusion of ants was far more important than the exclusion of birds. Indeed, almost all groups of arthropods had higher abundance in ant‐excluded than in control trees, whereas only dermapterans were more abundant in bird‐excluded than in control trees. A more detailed analysis conducted on spiders also showed that the effect of ant exclusion was limited to a few families rather than being widespread over the entire diverse spectrum of spiders. 4. Our results suggest that the relative importance of vertebrate and invertebrate predators in regulating arthropod populations largely depends on the nature of the predator–prey system.  相似文献   
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The Revised Classification of Eukaryotes   总被引:1,自引:0,他引:1  
This revision of the classification of eukaryotes, which updates that of Adl et al. [J. Eukaryot. Microbiol. 52 (2005) 399], retains an emphasis on the protists and incorporates changes since 2005 that have resolved nodes and branches in phylogenetic trees. Whereas the previous revision was successful in re‐introducing name stability to the classification, this revision provides a classification for lineages that were then still unresolved. The supergroups have withstood phylogenetic hypothesis testing with some modifications, but despite some progress, problematic nodes at the base of the eukaryotic tree still remain to be statistically resolved. Looking forward, subsequent transformations to our understanding of the diversity of life will be from the discovery of novel lineages in previously under‐sampled areas and from environmental genomic information.  相似文献   
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The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na+] and [K+] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na+‐selective class I‐HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single‐nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near‐isogenic lines (NILs): 157‐14 (double homozygote for the cheesmaniae alleles) and 157‐17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157‐14 in comparison with 157‐17. A significant difference between NILs was also found for [K+] and the [Na+]/[K+] ratio in leaf and stem but not for [Na+] arising a disagreement with the corresponding RIL population. Their association with leaf [Na+] and salt tolerance in tomato is also discussed.  相似文献   
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In developing CNS D1 dopamine receptor-imaging agents with improved specificity and longer brain retention, an iodinated D1 ligand was synthesized. In vitro and in vivo radiolabeling studies of a new iodinated benzazepine, TISCH [7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3- benzazepine], an analog of SCH 23390 (7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepin e), were investigated. After an intravenous injection, the R(+) isomer of TISCH showed high brain uptake in rats (2.20 and 0.57% dose per whole brain at 2 and 60 min, respectively). The striatum/cerebellum ratio increased progressively with time (12 at 60 min). Ex vivo autoradiography of rat brain sections, after intravenous injection of R(+)-[125I]TISCH, displayed the highest uptake in striatum and substantia nigra, regions known to have a high concentration of D1 receptors, whereas the S(-) isomer displayed no specific uptake. Furthermore, the specific uptake can be blocked by pretreatment with SCH 23390. In vitro binding studies using the rat striatum tissue preparation showed high specific and low nonspecific bindings (KD = 0.21 +/- 0.03 nM). The rank order of potency exhibiting high specificity to the D1 receptor was SCH 23390 greater than (+/-)-TISCH greater than (+)-butaclamol = (+/-)-FISCH [7-chloro-8-hydroxy-1-(4'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3-benzazepine] much greater than WB4101 = spiperone greater than dopamine, serotonin, (+/-)-propranolol, and naloxone. Imaging studies in a monkey with the resolved isomer, R(+)-[123I]TISCH, demonstrated a high uptake in the basal ganglia and prolonged retention. The preliminary data suggest that R(+)-TISCH is selective for the CNS D1 receptor and is potentially useful for in vivo and in vitro pharmacological studies. When labeled with iodine-123, it may be suitable for noninvasive imaging in humans.  相似文献   
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Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype.  相似文献   
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OBJECTIVE: This study was designed to characterize the reproducibility of measurement for tumor volumes and their longest tumor diameters (LDs) and estimate the potential impact of using changes in tumor volumes instead of LDs as the basis for response assessments. METHODS: We studied patients with advanced lung cancer who have been observed longitudinally with x-ray computed tomography in a multinational trial. A total of 71 time points from 10 patients with 13 morphologically complex target lesions were analyzed. A total of 6461 volume measurements and their corresponding LDs were made by seven independent teams using their own work flows and image analysis tools. Interteam agreement and overall interrater concurrence were characterized. RESULTS: Interteam agreement between volume measurements was better than between LD measurements (ı = 0.945 vs 0.734, P = .005). The variability in determining the nadir was lower for volumes than for LDs (P = .005). Use of standard thresholds for the RECIST-based method and use of experimentally determined cutoffs for categorizing responses showed that volume measurements had a significantly greater sensitivity for detecting partial responses and disease progression. Earlier detection of progression would have led to earlier changes in patient management in most cases. CONCLUSIONS: Our findings indicate that measurement of changes in tumor volumes is adequately reproducible. Using tumor volumes as the basis for response assessments could have a positive impact on both patient management and clinical trials. More authoritative work to qualify or discard changes in volume as the basis for response assessments should proceed.  相似文献   
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We describe a design of experiments (DoE) response surface modeling strategy to optimize the concentration of basal variables underpinning polyethylenimine (PEI) mediated transfection of different CHO-K1 derived parental cell populations in a chemically defined medium, specifically the relative concentration of linear 25 kD PEI, host CHO cells and plasmid DNA. Using recombinant secreted alkaline phosphatase (SEAP) reporter activity as the modeled response, a discrete simple maximum was predicted for each CHO host cell population. Differences between the modeled optima derived from host cell specific differences in PEI cytotoxicity, such that the PEI:cell interaction effectively limited PEI-DNA polyplex load at a relatively constant PEI:DNA ratio. However, across the three CHO host cell populations, SEAP reporter production was not proportional to plasmid DNA input at the host cell specific predicted basal variable optima. A 10-fold variation in SEAP reporter output per mass of plasmid DNA delivered was observed. To determine the cellular basis of this difference in transient productivity, host CHO cells were transfected with fluorescently labeled polyplexes followed by flow cytometric analysis. Each CHO host cell population exhibited a distinct functional phenotype, varying in the extent of PEI-DNA polyplex binding to the cell surface and degree of polyplex internalization. SEAP production was directly proportional to the level of polyplex internalization and heparan sulfate proteoglycan level. Taken together, these data show that choice of host CHO cell line is a critical parameter, which should rationally precede cell line specific transient production platform design using DoE methodology.  相似文献   
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