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91.
Genetics of tassel branch number in maize and its implications for a selection program for small tassel size 总被引:2,自引:0,他引:2
Dr. S. H. Schuetz Dr. J. J. Mock 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1978,53(6):265-271
Summary Tassel branch numbers of six crosses of maize (Zea mays L.) were analyzed to determine inheritance of this trait. Generation mean analyses were used to estimate genetic effects, and additive and nonadditive components of variance were calculated and evaluated for bias due to linkage. Both narrow-sense and broad-sense heritabilities were estimated. Additive genetic variance estimates were significant in five of the six crosses, whereas estimates of variance due to nonadditive components were significant in only three crosses. Additionally, estimates of additive variance components usually were larger than corresponding nonadditive components. There was no evidence for linkage bias in these estimates. Estimates of additive genetic effects were significant in four of six crosses, but significant dominance, additive × additive and additive × dominance effects also were detected. Additive, dominance, and epistatic gene action, therefore, all influenced the inheritance of tassel branch number, but additive gene action was most important. Both narrow-sense and broadsense heritability estimates were larger than those reported for other physiological traits of maize and corroborated conclusions concerning the importance of additive gene action inferred from analyses of genetic effects and variances. We concluded that selection for smalltasseled inbreds could be accomplished most easily through a mass-selection and/or pedigree-selection system. Production of a small-tasseled hybrid would require crossing of two small-tasseled inbreds. We proposed two genetic models to explain unexpected results obtained for two crosses. One model involved five interacting loci and the other employed two loci displaying only additive and additive × additive gene action.Journal Paper No. J-9231 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa 50011. Project No. 2152 相似文献
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Involvement of protein synthesis in frog pituitary homogenate (FPH)-induced progesterone production and/or accumulation in ovarian follicles was investigated. In amphibians, cycloheximide (C), an inhibitor of protein synthesis, inhibits progesterone and FPH-induced germinal vesicle breakdown (GVBD). However, the site and mechanisms of action of cycloheximide within ovarian follicles have not been elucidated. Intrafollicular progesterone produced by FPH is considered to mediate oocyte maturation; thus, cycloheximide may interfere with production and/or action of progesterone. Simultaneous treatment of FPH-stimulated follicles with cycloheximide inhibited FPH-induced progesterone accumulation (measured by RIA) and the accompanying-GVBD in a dose-dependent fashion. Inhibitory effects of cycloheximide on either FPH-induced progesterone production or GVBD were not reversed when follicles were washed and returned to fresh medium devoid of FPH and cycloheximide. However, subsequent restimulation of washed follicles with FPH resulted in increased progesterone levels and oocyte maturation. The extent of reversibility, in terms of GVBD and progesterone production, after FPH restimulation varied between animals. Pretreatment of follicles with cycloheximide for 6 hours, without FPH, had little or no effect on progesterone production when follicles were washed and treated with FPH. Delayed addition of cycloheximide to follicles following FPH stimulation blocked further progesterone accumulation as indicated by measurement of intrafollicular progesterone at the time of cycloheximide addition and at the end of the incubation period. The results indicate that cycloheximide rapidly inhibits progesterone production and that continuous protein synthesis is required for progesterone accumulation. Furthermore, protein synthesis does not appear to be required for progesterone metabolism since intrafollicular progesterone declined with prolonged culture even in the presence of cycloheximide. The nature of protein(s) involved in follicular progesterone production remains to be elucidated. FPH mediation of oocyte maturation within ovarian follicles appears to depend upon protein synthesis in somatic follicle cells, which is required for progesterone production, and in the oocyte, to mediate the response to the steroid trigger. 相似文献
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Schuetz A Allali-Hassani A Martín F Loppnau P Vedadi M Bochkarev A Plotnikov AN Arrowsmith CH Min J 《The EMBO journal》2006,25(18):4245-4252
Histone methylation at specific lysine residues brings about various downstream events that are mediated by different effector proteins. The WD40 domain of WDR5 represents a new class of histone methyl-lysine recognition domains that is important for recruiting H3K4 methyltransferases to K4-dimethylated histone H3 tail as well as for global and gene-specific K4 trimethylation. Here we report the crystal structures of full-length WDR5, WDR5Delta23 and its complexes with unmodified, mono-, di- and trimethylated histone H3K4 peptides. The structures reveal that WDR5 is able to bind all of these histone H3 peptides, but only H3K4me2 peptide forms extra interactions with WDR5 by use of both water-mediated hydrogen bonding and the altered hydrophilicity of the modified lysine 4. We propose a mechanism for the involvement of WDR5 in binding and presenting histone H3K4 for further methylation as a component of MLL complexes. 相似文献
98.
Ulrich DL Lynch J Wang Y Fukuda Y Nachagari D Du G Sun D Fan Y Tsurkan L Potter PM Rehg JE Schuetz JD 《The Journal of biological chemistry》2012,287(16):12679-12690
Abcb6 is a mammalian mitochondrial ATP-binding cassette (ABC) transporter that regulates de novo porphyrin synthesis. In previous studies, haploinsufficient (Abcb6(+/-)) embryonic stem cells showed impaired porphyrin synthesis. Unexpectedly, Abcb6(-/-) mice derived from these stem cells appeared phenotypically normal. We hypothesized that other ATP-dependent and/or -independent mechanisms conserve porphyrins. Here, we demonstrate that Abcb6(-/-) mice lack mitochondrial ATP-driven import of coproporphyrin III. Gene expression analysis revealed that loss of Abcb6 results in up-regulation of compensatory porphyrin and iron pathways, associated with elevated protoporphyrin IX (PPIX). Phenylhydrazine-induced stress caused higher mortality in Abcb6(-/-) mice, possibly because of sustained elevation of PPIX and an inability to convert PPIX to heme despite elevated ferrochelatase levels. Therefore, Abcb6 is the sole ATP-dependent porphyrin importer, and loss of Abcb6 produces up-regulation of heme and iron pathways necessary for normal development. However, under extreme demand for porphyrins (e.g. phenylhydrazine stress), these adaptations appear inadequate, which suggests that under these conditions Abcb6 is important for optimal survival. 相似文献
99.
Adam Csordas Fabian Nietlispach Philipp Schuetz Andreas Huber Beat Müller Francesco Maisano Maurizio Taramasso Igal Moarof Slayman Obeid Barbara E. St?hli Martin Cahenzly Ronald K. Binder Christoph Liebetrau Helge M?llmann Won-Keun Kim Christian Hamm Thomas F. Lüscher 《PloS one》2015,10(12)
Background
Conventional surgical risk scores lack accuracy in risk stratification of patients undergoing transcatheter aortic valve replacement (TAVR).Elevated levels of midregional proadrenomedullin (MR-proADM) levels are associated with adverse outcome not only in patients with manifest chronic disease states, but also in the general population.Objectives
We investigated the predictive value of MR-proADM for mortality in an unselected contemporary TAVR population.Methods
We prospectively included 153 patients suffering from severe aortic stenosis who underwent TAVR from September 2013 to August 2014. This population was compared to an external validation cohort of 205 patients with severe aortic stenosis undergoing TAVR. The primary endpoint was all cause mortality.Results
During a median follow-up of 258 days, 17 out of 153 patients who underwent TAVR died (11%). Patients with MR-proADM levels above the 75th percentile (≥ 1.3 nmol/l) had higher mortality (31% vs. 4%, HR 8.9, 95% CI 3.0–26.0, P < 0.01), whereas patients with EuroSCORE II scores above the 75th percentile (> 6.8) only showed a trend towards higher mortality (18% vs. 9%, HR 2.1, 95% CI 0.8–5.6, P = 0.13). The Harrell’s C-statistic was 0.58 (95% CI 0.45–0.82) for the EuroSCORE II, and consideration of baseline MR-proADM levels significantly improved discrimination (AUC = 0.84, 95% CI 0.71–0.92, P = 0.01). In bivariate analysis adjusted for EuroSCORE II, MR-proADM levels ≥1.3 nmol/l persisted as an independent predictor of mortality (HR 9.9, 95% CI (3.1–31.3), P <0.01) and improved the model’s net reclassification index (0.89, 95% CI (0.28–1.59). These results were confirmed in the independent validation cohort.Conclusions
Our study identified MR-proADM as a novel predictor of mortality in patients undergoing TAVR. In the future, MR-proADM should be added to the commonly used EuroSCORE II for better risk stratification of patients suffering from severe aortic stenosis. 相似文献100.
Ananworanich J Schuetz A Vandergeeten C Sereti I de Souza M Rerknimitr R Dewar R Marovich M van Griensven F Sekaly R Pinyakorn S Phanuphak N Trichavaroj R Rutvisuttinunt W Chomchey N Paris R Peel S Valcour V Maldarelli F Chomont N Michael N Phanuphak P Kim JH;RV/SEARCH Study Group 《PloS one》2012,7(3):e33948