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31.
Kvaløy K Nilsen H Steinsbekk KS Nedal A Monterotti B Akbari M Krokan HE 《Mutation research》2001,461(4):325-338
32.
Antigen-specific regulatory T cells develop via the ICOS-ICOS-ligand pathway and inhibit allergen-induced airway hyperreactivity 总被引:41,自引:0,他引:41
Akbari O Freeman GJ Meyer EH Greenfield EA Chang TT Sharpe AH Berry G DeKruyff RH Umetsu DT 《Nature medicine》2002,8(9):1024-1032
Asthma is caused by T-helper cell 2 (Th2)-driven immune responses, but the immunological mechanisms that protect against asthma development are poorly understood. T-cell tolerance, induced by respiratory exposure to allergen, can inhibit the development of airway hyperreactivity (AHR), a cardinal feature of asthma, and we show here that regulatory T (T(R)) cells can mediate this protective effect. Mature pulmonary dendritic cells in the bronchial lymph nodes of mice exposed to respiratory allergen induced the development of T(R) cells, in a process that required T-cell costimulation via the inducible costimulator (ICOS-ICOS-ligand pathway. The T(R) cells produced IL-10, and had potent inhibitory activity; when adoptively transferred into sensitized mice, T(R) cells blocked the development of AHR. Both the development and the inhibitory function of regulatory cells were dependent on the presence of IL-10 and on ICOS-ICOS-ligand interactions. These studies demonstrate that T(R) cells and the ICOS-ICOS-ligand signaling pathway are critically involved in respiratory tolerance and in downregulating pulmonary inflammation in asthma. 相似文献
33.
Azadeh?BadieeEmail author Hans?Geir?Eiken Vidar?M?Steen Roger?L?vlie 《BMC biotechnology》2003,3(1):23
Background
Several different cDNA labeling methods have been developed for microarray based gene expression analysis. We have examined the accuracy and reproducibility of such five commercially available methods in detection of predetermined ratio values from target spike mRNAs (A. thaliana) in a background of total RNA. The five different labeling methods were: direct labeling (CyScribe), indirect labeling (FairPlay? – aminoallyl), two protocols with dendrimer technology (3DNA® Array 50? and 3DNA® submicro?), and hapten-antibody enzymatic labeling (Micromax? TSA?). Ten spike controls were mixed to give expected Cy5/Cy3 ratios in the range 0.125 to 6.0. The amounts of total RNA used in the labeling reactions ranged from 5 – 50 μg.Results
The 3DNA array 50 and CyScribe labeling methods performed best with respect to relative deviation from the expected values (16% and 17% respectively). These two methods also displayed the best overall accuracy and reproducibility. The FairPlay method had the lowest total experimental variation (22%), but the estimated values were consistently higher than the expected values (36%). TSA had both the largest experimental variation and the largest deviation from the expected values (45% and 48% respectively).Conclusion
We demonstrate the usefulness of spike controls in validation and comparison of cDNA labeling methods for microarray experiments.34.
Drosophila meridionalis is a cactus-breeding species with a wide distribution in South America. Most populations of this species are geographically isolated, what provides a promising scenario for studying evolution. Former studies of this species revealed a remarkable karyotypic variation among its populations. Up to six distinct metaphase chromosomes were described, showing that this species is polymorphic at least at the chromosomal level. In order to elucidate the taxonomic status of populations showing different metaphase chromosomes, we analyzed the courtship song of five populations of D. meridionalis in South and Southeastern Brazil. In addition, we analyzed the metaphase chromosomes of each population. Our results show that, despite the two karyotype observed, most courtship song parameters did not vary among the populations. Altogether, our results suggest that D. meridionalis from South and Southeastern Brazil represents one species with an inter-population chromosomal variability. 相似文献
35.
Titanium carbide-graphite (TiC/C) composite was successfully synthesized from Ti and C starting elemental powders using self-propagating high-temperature synthesis technique in an ultra-high plasma inert medium in a single stage. The TiC was exposed to a high-temperature inert medium to allow recrystallization. The product was then characterized using field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), Rietveld refinement, nanoindentation, and micro-hardness to determine the product’s properties. The recorded micro-hardness of the product was 3660 HV, which is a 14% enhancement and makes is comparable to TiC materials. 相似文献
36.
Rogério P. Mateus Luciana P.B. Machado Evandro M. Moraes Fábio M. Sene 《Biochemical Systematics and Ecology》2010
Drosophila antonietae and Drosophila gouveai are allopatric, cactophilic, cryptic and endemic of South America species, which aedeagus morphology is considered the main diagnostic character. In this work, single close populations from the edge distributions of each species, located in an “introgressive corridor”, were analyzed regarding temporal isozenzymatic genetic variability. Isocitrate dehydrogenase (Idh) appeared as a diagnostic locus between D. antonieate and D. gouveai because each population was fixed for different alleles. Moreover, several polymorphic loci showed accentuated divergence in the allele frequency, as evidenced by Nei’s I (0.3188) and D (1.1432), and also by Reynolds’ genetic distance and identity (1.3207 and 0.7331, respectively). Our results showed that, in spite of the very similar external morphology, related evolutionary histories, close distributions, and events of introgression in the studied area, these cryptic species have high allozymatic differentiation, and this is discussed here. 相似文献
37.
El-Armouche A Wahab A Wittköpper K Schulze T Böttcher F Pohlmann L King SB DuMond JF Gerloff C Böger RH Eschenhagen T Carrier L Donzelli S 《Biochemical and biophysical research communications》2010,397(2):340-344
Haplotype, which is the sequence of SNPs in a specific chromosome, plays an important role in disease association studies. However, current sequencing techniques can detect the presence of SNP sites, but they cannot tell which copy of a pair of chromosomes the alleles belong to. Moreover, sequencing errors that occurred in sequencing SNP fragments make it difficult to determine a pair of haplotypes from SNP fragments. To help overcome this difficulty, the haplotype assembly problem is defined from the viewpoint of computation, and several models are suggested to tackle this problem. However, there are no freely available web-based tools to overcome this problem as far as we are aware. In this paper, we present a web-based application based on the genetic algorithm, named HapAssembler, for assembling a pair of haplotypes from SNP fragments. Numerical results on real biological data show that the correct rate of the proposed application in this paper is greater than 95% in most cases. HapAssembler is freely available at http://alex.chonnam.ac.kr/~drminor/hapHome.htm. Users can choose any model among four models for their purpose and determine haplotypes from their input data. 相似文献
38.
A major limitation for the use of Cre recombinase is its toxicity and a lack of temporal control over its activity. We have
developed a new recombination system using Cre recombinase α-complementation. Cre recombinase was divided and one fragment
(β) was introduced into cells between two loxP sites with a CMV promoter in the upstream. The gene of interest (EGFP) was
positioned just downstream of this construct. Cre recombinase activity was recovered by adding the other part of the molecule
(α) to cells as a protein fragment, as evidenced by the expression of EGFP under the control of the CMV promoter. The activity
of fragmented cre reached 68% of that of the wild type enzyme at 1 μM α-protein. 相似文献
39.
The fabrication of Bacillus subtilis endospore imprinted conducting polymer films and subsequent electrochemical detection of bound spores is reported. Imprinted films were prepared by absorbing spores on the surface of glassy carbon electrodes upon which a polypyrrole, followed by a poly(3-methylthiophene), layer were electrochemically deposited. Spore template release was achieved through soaking the modified electrode in DMSO. Binding of endospores to imprinted films could be detected via impedance spectroscopy by monitoring changes in Y' (susceptance) using Mn(II)Cl2 (0.5M pH 3) as the supporting electrolyte. Here, the change in Y' could be correlated to spore densities between 10(4) and 10(7)cfu/ml. More sensitive detection of absorbed spores was achieved by following endospore germination via changes in film charge as measured using cyclic voltammetry. Here, imprinted films were submerged in spore suspensions to permit absorption, heat activated at 70 degrees C for 10 min prior to transferring to an electrochemical cell containing germination activators. By using the assay format it was possible to detect 10(2)cfu/ml. The observed changes in film charge could be attributed to the interaction of the supporting conducting polymer with dipicolinic acid (DPA) and other constituents released from the core in the course of germination. In all cases, it was not possible to regenerate the imprinted films without losing electrode response. In summary, the study has provided proof-of-concept for fabricating microbial imprinted films using conducting polymers. 相似文献
40.
Tsinkalovsky O Smaaland R Rosenlund B Sothern RB Hirt A Steine S Badiee A Abrahamsen JF Eiken HG Laerum OD 《Journal of biological rhythms》2007,22(2):140-150
Time-dependent variations in clock gene expression have recently been observed in mouse hematopoietic cells, but the activity of these genes in human bone marrow (BM) has so far not been investigated. Since such data can be of considerable clinical interest for monitoring the dynamics in stem/progenitor cells, the authors have studied mRNA expression of the clock genes hPer1 , hPer2, hCry1, hCry2, hBmal1, hRev-erb alpha, and hClock in human hematopoietic CD34-positive (CD34( +)) cells. CD34(+) cells were isolated from the BM samples obtained from 10 healthy men at 6 times over 24 h. In addition, clock gene mRNA expression was analyzed in the whole BM in 3 subjects. Rhythms in serum cortisol, growth hormone, testosterone, and leukocyte counts documented that subjects exhibited standardized circadian patterns. All 7 clock genes were expressed both in CD34(+) cells and the whole BM, with some differences in magnitude between the 2 cell populations. A clear circadian rhythm was shown for hPer1, hPer2, and hCry2 expression in CD34(+) cells and for hPer1 in the whole BM, with maxima from early morning to midday. Similar to mouse hematopoietic cells, h Bmal1 was not oscillating rhythmically. The study demonstrates that clock gene expression in human BM stem/progenitor cells may be developmentally regulated, with strong or weaker circadian profiles as compared to those reported in other mature tissues. 相似文献