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1.
Thorsten Thye Genevieve Scarisbrick Edmund N. L. Browne Margaret Amanua Chinbuah John Gyapong Ivy Osei Ellis Owusu-Dabo Stefan Niemann Sabine Rüsch-Gerdes Christian G. Meyer Rolf D. Horstmann 《PloS one》2009,4(7)
The gene of Cytotoxic T Lymphocyte-associated Antigen 4 (CTLA4), a negative regulator of T lymphocytes, contains a single-nucleotide polymorphism (SNP) at position +6230A->G (ct60A->G), which has been found associated with several autoimmune diseases and appears to reduce T-cell inhibitory activity. In Ghana, West Africa, we compared the frequencies of CTLA4 +6230 A/G and 6 haplotype-tagging SNPs in 2010 smear-positive, HIV-negative patients with pulmonary tuberculosis (TB) and 2346 controls matched for age, gender and ethnicity. We found no difference in allele frequencies between cases and controls. However, +6230A and a distinct CTLA4 haplotype and a diplotype comprising the +6230A allele were significantly less frequent among cases with large opacities in chest radiographs compared to those with small ones (Pcorrected [cor] = 0.002, Pcor = 0.00045, P = 0.0005, respectively). This finding suggests that an increased T-cell activity associated with the CTLA4 +6230G allele contributes to pathology rather than to protection in pulmonary TB. 相似文献
2.
A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects, but substantial for QTL with over-dominance, for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For over-dominant QTL, maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing. 相似文献
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When both cotyledons of light-grown sunflower seedlings (Helianthusannuus L.) were darkened by covering them with aluminium foil,the resulting increase in the rate of elongation of the hypocotylwas closely proportional to the associated reduction in seedlingtranspiration and to the increase in xylem water potential (PX.Covering only one cotyledon induced curvature away from thatside. This response was associated with a higher PX in the vascularbundles connected directly with the covered cotyledon than inthose connected with the illuminated cotyledon. The water contentof peripheral tissues of the hypocotyl below the covered cotyledonwas also higher than that of similar samples from below theilluminated cotyledon. These results are consistent with thehypothesis that the effect of darkening the cotyledons on thegrowth and curvature of the hypocotyl is mediated by hydraulicsignalling, characterized by transmission to the hypocotyl ofan increase in PX resulting from the reduction in cotyledontranspiration. Key words: Cotyledons, Helianthus annuus, hydraulic signalling, hypocotyl, transpiration, water potential 相似文献
5.
Estimation of whole-plant resistance to gaseous exchange independent of leaf temperature measurement 总被引:1,自引:1,他引:0
For studies into the uptake of mercury vapor by wheat (Triticum aestivum), a simple theory and plant chamber were employed to estimate total leaf resistance of whole plants to water vapor exchange. The estimates were independent of leaf temperature, for which mean values were indirectly determined. The approach involved the measurement, at steady-state conditions, of the net change in water vapor flux per unit of leaf surface (Δqv) in response to a small induced change in absolute humidity (ΔCa). Assuming that total leaf resistance (rl) was constant and that change in leaf temperature (Tl) was negligible, total leaf resistance was calculated from the equation, [Formula: see text] 相似文献
6.
When the entire digital web space has been destroyed by burn scarring and there is a contracture of the volar aspect of the web as well as the dorsum, Z-plasties and skin grafts alone seldom produce a satisfactory web space. During the past 3 years, for the release of 46 contracted web spaces in 20 burned patients, we have turned a rectangular flap from the dorsal surface of the web through into an inverted-T incision in the palm. The adjacent sides of the defects have been skin grafted. In all these patients, we obtained satisfactory release of the contracture and restoration of the web space. 相似文献
7.
This paper describes the derivation and use of predictive retention coefficients for the reversed-phase high-performance liquid chromatography of peptides. The use of predicted elution positions in the isolation of peptides is illustrated by two examples where peptides, whose existence was postulated from cDNA sequence data, have been successfully isolated. The combination of the powerful chromatographic technology and the ability to predict the elution positions of peptides based on their composition provides a very potent method for the isolation of peptides from biological tissues. 相似文献
8.
Inhibition of mitosis in fertilized sea urchin eggs by inhibition of the cyclic AMP-dependent protein kinase 总被引:1,自引:0,他引:1
Inhibition of cAMP-dependent protein kinase activity by microinjection of a specific physiologic protein inhibitor into sea urchin eggs inhibits the first cleavage after fertilization. Inhibition apparently occurs at some time prior to or during formation of the mitotic spindle. Measurement of the total protein kinase activity of sea urchin egg homogenates after fertilization showed that cAMP-dependent phosphorylation increases after fertilization and then declines prior to or at the time of the first cleavage. It is concluded that a cAMP-dependent phosphorylation plays a significant role in events leading to regulation of mitotic spindle assembly. 相似文献
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