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91.
Larsen K Macleod D Nihlberg K Gürcan E Bjermer L Marko-Varga G Westergren-Thorsson G 《Journal of proteome research》2006,5(6):1479-1483
Haptoglobin is an acute-phase glycoprotein considered to be involved in tissue repair and is produced by fibroblasts and inflammatory cells. By using a gel-based proteomic approach, we show for the first time a possible role for haptoglobin in the differentiation of fibroblast progenitor cells, termed fibrocytes, in patients with mild asthma. Bronchoalveolar lavage fluid (BALF) was performed to sample circulating fibrocytes from patients with mild asthma and nonasthmatic control subjects. Fibrocytes from the airway lumen were characterized by triple staining of the markers CD34/CD45R0/alpha-smooth muscle actin, and subjected to confocal microscopy. The protein expression pattern was analyzed using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). Elevated levels of haptoglobin expression in BALF was reported in a sub-group of patients with mild asthma (p < 0.05) when compared to the other subjects. In addition, this increase in haptoglobin was accompanied by differentiation of fibrocytes into fibroblast-like cells. When further analyzing the expression pattern of haptoglobin isoforms, a heterozygous expression was detected in the patients where fibrocyte differentiation could be observed. These data raise the possibility that an acute and specific inflammatory state facilitates the differentiation of fibroblast progenitor cells into activated fibroblasts. Furthermore, this study proposes a novel role for haptoglobin in airway remodeling in patients with asthma. 相似文献
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94.
Background
It has been reported in the quantitative trait locus (QTL) literature that when testing for QTL location and effect, the statistical power supporting methodologies based on two markers and their estimated genetic map is higher than for the genetic map independent methodologies known as single marker analyses. Close examination of these reports reveals that the two marker approaches are more powerful than single marker analyses only in certain cases.Simulation studies are a commonly used tool to determine the behavior of test statistics under known conditions. We conducted a simulation study to assess the general behavior of an intersection test and a two marker test under a variety of conditions. The study was designed to reveal whether two marker tests are always more powerful than intersection tests, or whether there are cases when an intersection test may outperform the two marker approach.We present a reanalysis of a data set from a QTL study of ovariole number in Drosophila melanogaster.Results
Our simulation study results show that there are situations where the single marker intersection test equals or outperforms the two marker test. The intersection test and the two marker test identify overlapping regions in the reanalysis of the Drosophila melanogaster data. The region identified is consistent with a regression based interval mapping analysis.Conclusion
We find that the intersection test is appropriate for analysis of QTL data. This approach has the advantage of simplicity and for certain situations supplies equivalent or more powerful results than a comparable two marker test.95.
Multiple nuclear-gene phylogenies: application to pinnipeds and comparison with a mitochondrial DNA gene phylogeny 总被引:8,自引:1,他引:7
Phylogenetic analyses of closely related species should use information
from multiple, independent genes with relatively high rates of sequence
evolution. To investigate species for which there are few prior sequence
data for single-copy nuclear (scnDNA) genes, primers for gene amplification
can be designed to highly conserved regions of exons in order to amplify
both coding (exons) and noncoding (introns) sequences. We have explored
this approach in a phylogenetic analysis of six species of pinnipeds that,
together with terrestrial carnivore outgroups, encompass divergence times
< or = 40-50 Mya. We sequenced one intron from each of the aldolase A
(ALD-A), aldolase C (ALD-C), and histone H2AF genes; one exon from the
major-histocompatibility-complex DQA gene; a H2AF processed pseudogene (psi
H2AF); and, for comparison with the nuclear genes, the 5' portion of the
mitochondrial DNA (mtDNA) control region. The pinniped psi H2AF genes were
found to be of limited use because they were paralogous with the gene in
the outgroup. The rate of silent substitution in scnDNA (primarily introns)
was 5-10-fold lower than that for mtDNA control region I, and scnDNA
sequence divergence increased linearly with time < or = 40-50 Mya.
Alleles at three polymorphic scnDNA loci (ALD-A, H2AF, and DQA) in the
southern elephant seal were paraphyletic with respect to the allele from
the closely related northern elephant seal, while the more numerous mtDNA
alleles were monophyletic. This we attribute to the consequences of a
higher mutation rate rather than to a lower effective population size of
mtDNA compared with scnDNA. Within the short (i.e., < 500-bp) sequences
of individual scnDNA sequences, phylogenetically informative variation was
insufficient to obtain robust phylogenies. However, the combined scnDNA
sequences produced a well-supported phylogeny congruent with that derived
from mtDNA. This analysis illustrates the high resolution of mtDNA
sequences compared with a similar length of scnDNA sequence, but it also
demonstrates the utility of combining information from multiple short
scnDNA sequences obtained using broadly applicable primers.
相似文献
96.
J. Werner Zolg Alexander J. Macleod John G. Scaife Richard L. Beaudoin 《In vitro cellular & developmental biology. Plant》1984,20(3):205-215
Summary Synchronization ofPlasmodium falciparum cultured in vitro results in a one-step growth pattern that allows the study of stage-specific metabolic activities of the
parasites. Lactic acid (LA) was selected as a metabolic marker, and the concentration of this end product found in spent media
was correlated with the different erythrocytic stages of the parasites. When the medium was changed at 12 h intervals, cultures
containing predominantly trophozoites produced 3.66±0.55 μmol LA per 12 h per 107 parasitized cells (n=26), an amount of LA that is about 8 to 20 times higher than that found in corresponding cultures containing predominantly
ring forms. Depending on the stage of development, parasitized red blood cells produced between 5 and 100 times more LA than
uninfected erythrocytes (3.72±0.62 μmol LA per 12 hours per 109 red blood cells) (n=41) when cultured under identical conditions. The intraerythrocytic development of the parasites was not impaired by exposure
to extracellular concentrations of LA up to 12 mM over a 12 h period. The growth resulting in such cultures was described as uninhibited and was characterized by a multiplication
index of 10 or higher. Above the threshold of 12 mM of LA, progressive inhibition of parasite development occurred. The stage-specific LA production reported can be used to
predict the amount of LA that will have accumulated at the end of a subsequent 12 h incubation period during synchronized
in vitro growth ofPlasmodium falciparum. Using these values, it is possible to establish an optimal medium exchange schedule, thereby assuring uninhibited growth
and a correspondingly high parasite yield.
J. W. Z. was supported during part of this study by a long-term fellowship of the European Molecular Biology Organization,
Heidelberg, West Germany, followed by a Research Associateship from the National Research Council, Washington, D.C. The project
was supported by grants from the Medical Research Council to J. G. S. and by the Naval Research and Development Command, Work
Unit No. 3M 162 770 A871 AE 312. The opinions or assertions contained herein are the private ones of the authors and are not
to be construed as official or reflecting the views of the U.S. Navy Department or the naval service at large. 相似文献
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98.
Exchange diffusion of dopamine induced in planar lipid bilayer membranes by the ionophore X537A 下载免费PDF全文
RW Holz 《The Journal of general physiology》1977,69(5):633-653
The ionophore X537A causes a large increase in the [(14)C]dopamine (a catecholamine) permeability of planar bilayer membranes. Dopamine transport increases linearly with the ionophore concentration. At relatively high concentrations in the presence of dopamine, the ionophore omdices a conductance which is nearly ideally selective for the dopamine cation. However, the total dopamine flux as determined in tracer experiments is not affected by an electric field and is over 10(5) times larger than predicted from the estimated dopamine conductance. Increasing the dopamine concentration on the side containing radioactive dopamine (the cis side) saturates the dopamine transport. This saturation is relieved by trans addition of nonradioactive dopamine, tyramine, H(+), or K(+). With unequal concentrations of dopamine cis and trans (49 and 12.5 mM), the unidirectional dopamine fluxes are equal. Increasing H(+) cis and trans decreases dopamine transport. It is concluded that at physiological pH, the X537A-induced transport of dopamine occurs via an electrically silent exchange diffusion of dopamine cation with another cation (e.g., dopamine(+), H(+), or K(+)). X537A induces a Ca(++)-independent release of catecholamines from sympathetic nerves by interfering with intracellular storage within storage vesicles (R.W. Holz. 1975. Biochim. Biophys. Acta. 375:138-152). It is suggested that X537A causes an exchange of intravesicular catecholamine with a cytoplasmic cation (perhaps K(+) or H(+)) across the storage vesicle membrane. 相似文献
99.
Distribution of lipopolysaccharide and the detection of a new subfraction in the cell envelope of a marine pseudomonad. 总被引:3,自引:3,他引:0 下载免费PDF全文
The three outer layers of the cell envelope of marine pseudomonad B-16, the loosely bound outer layer, the outer membrane, and the periplasmic space layer, are the only ones containing appreciable amounts of both lipid and carbohydrate. These layers and a fraction released into the medium during growth of the cells were examined for the presence of common antigens by double immunodiffusion using anti-whole serum. Each of the layers, the medium fraction, and lipopolysaccharide (LPS) isolated from the organism were shown to contain two or more diffusible components showing reactions of identity. Thus LPS is found in each of the three outer layers of the cell envelope of this gram-negative bacterium. The periplasmic space layer was found to contain a fraction accounting for 20% of the dry weight of the layer, which was sedimentable at 30,000 x g and contained lipid, protein, and carbohydrate. Double-immunodiffusion tests indicated that the fraction contained at least one of the two antigens present in isolated LPS. A particulate material was released by the cells during growth which gave a positive test for 2-keto-3-deoxyoctulosonic acid and cross-reacted serologically with LPS. 相似文献