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Symbiotic nodule formation on legume roots is characterized with a series of developmental reprograming in root tissues, including extensive proliferation of cortical cells. We examined a possible involvement of the target of rapamycin (TOR) pathway, a central regulator of cell growth and proliferation in animals and yeasts, during soybean nodule development. Our results show that transcription of both GmTOR and its key downstream effector, GmS6K1, are activated during nodulation, which is paralleled with higher kinase activities of these gene products as well. RNAi-mediated knockdown of GmS6K1 impaired the nodule development with severely reduced nodule weight and numbers. In addition, expression of a few nodulins including leghemoglobin was also decreased, and consequently nitrogen fixation was found to be reduced by half. Proteomic analysis of the GmS6K1-RNAi nodules identified glutamine synthetase (GS), an essential enzyme for nitrogen assimilation in nodules, as one of the proteins that are significantly down regulated. These results appear to provide solid evidence for a functional link between GmS6K1 and nodule development.

Although over 30 common genetic susceptibility loci have been identified to be independently associated with coronary artery disease (CAD) risk through genome-wide association studies (GWAS), genetic risk variants reported to date explain only a small fraction of heritability. To identify novel susceptibility variants for CAD and confirm those previously identified in European population, GWAS and a replication study were performed in the Koreans and Japanese. In the discovery stage, we genotyped 2123 cases and 3591 controls with 521 786 SNPs using the Affymetrix SNP Array 6.0 chips in Korean. In the replication, direct genotyping was performed using 3052 cases and 4976 controls from the KItaNagoya Genome study of Japan with 14 selected SNPs. To maximize the coverage of the genome, imputation was performed based on 1000 Genome JPT+CHB and 5.1 million SNPs were retained. CAD association was replicated for three GWAS-identified loci (1p13.3/SORT1 (rs599839), 9p21.3/CDKN2A/2B (rs4977574), and 11q22.3/ PDGFD (rs974819)) in Koreans. From GWAS and a replication, SNP rs3782889 showed a strong association (combined P=3.95 × 10(-14)), although the association of SNP rs3782889 doesn't remain statistically significant after adjusting for SNP rs11066015 (proxy SNP with BRAP (r(2)=1)). But new possible CAD-associated variant was observed for rs9508025 (FLT1), even though its statistical significance did marginally reach at the genome-wide a significance level (combined P=6.07 × 10(-7)). This study shows that three CAD susceptibility loci, which were previously identified in European can be directly replicated in Koreans and also provides additional evidences implicating suggestive loci as risk variants for CAD in East Asian.

Homeobox genes are essential regulators of plant development. ATHB23, a class I homeodomain leucine zipper gene of Arabidopsis, was found to be induced by treatment with the phytohormone gibberellin (GA). In order to clarify its role in development, we performed a histochemical analysis of transgenic plants containing a construct with a GUS::GFP reporter under the control of the 1.5 kb upstream region of ATHB23. The construct was mainly expressed in young leaves and the styles of flowers but not in mature leaves. Microscopic examination of young leaves revealed that it was expressed in the adaxial domain of leaf primordia and the rib meristem. Expression of ATHB23, like that of GA5 encoding GA 20-oxidase, was reduced in mutants related to adaxial-abaxial leaf polarity (phb-1d, se-2, and kan1 kan2). Reduced expression of the GUS::GFP reporter gene was also observed in an se-2 background. These results indicate that ATHB23 is under the control of GA and other activators such as PHB, and is involved in establishing polarity during leaf development.

The gamma prime precipitation strengthening behavior and oxide dispersion strengthening behavior of mechanically alloyed oxide dispersion strengthened (ODS) Ni-base superalloys have been investigated. The most important microstructural feature affecting the elevated temperature strength of ODS alloys was found to be the grain aspect ratio. Grain aspect ratio after zone annealing was sensitively related to the primary grain size in as-extruded Ni-base superalloy. There was a suitable range of primary grain size to obtain a coarse elongated grain structure after zone annealing. The large grain aspect ratio above a critical value of about 20 resulted in an increase in stress-rupture life more than two orders of magnitude at 950°C. The size and distribution of the gamma prime precipitates were dependent on the solution heat treatment conditions. The microstructural parameters on the gamma prime precipitates significantly affected on the stress-rupture property of ODS Ni-base superalloy at the intermediate temperature range.

Oxide dispersion strengthened (ODS) superalloys produced by mechanical alloying (MA) have attracted great attention as advanced high-temperature materials, because they can retain useful strength up to a relatively high fraction of their melting points. Mechanical alloying is a dry, high-energy ball-milling process that produces composite metal powders with controlled, extremely fine micostructures. Mechanically alloyed powders are sealed in a steel can and are consolidated by extrusion and then subjected to conventional hot and cold working processes, m The asextruded ODS superalloys usually have an equiaxed, finegrained structure resulting from the primary recrystallization during hot extrusion. A final annealing at very high temperature is required to develop a stable, coarse grain structure by secondary recrystallization, one that is suitable for the most demanding stress-rupture applications. The attractive high-temperature strengths of ODS superalloys are primarily due to the presence of uniformly dispersed fine oxide particles. These oxide particles produce a dispersion strengthening effect by acting as barriers to dislocation motion.tEl In addition to the dispersion strengthening from oxide particles, the other important microstructural features affecting the elevated temperature strength of ODS superalloys are the grain size and the grain shape represented by the grain aspect ratio (GAR), which is a ratio of grain length, L, to grain width, I47. The accumulation of creep damage on transverse boundaries of ODS superalloys