Wheat TaMYB1A Negatively Regulates the Phenylpropanoid Pathway and Plant Height / 中国生物化学与分子生物学报

The phenylpropanoid pathway is one of the important pathways for synthesizing plant secondary metabolites, which can produce lignin, flavonoid, and sinapoylmalate. These compounds can not only affect the plant growth, development, and stress response, but also be used to produce perfume, pesticide, dye, medicine, feed, and biomass energy. R2R3-MYBs play important roles in regulating plant secondary metabolism, organ development, and in responding to environmental stresses. Wheat (Triticum aestivum L.) is an important food crop, but lots of straw will be produced accompanied by grain yields. Therefore, elucidating the function and regulatory mechanism of R2R3 MYBs of wheat is crucial for the effective utilization of the wheat straw. RT-PCR results showed that TaMYB1A was highly expressed in the wheat stems, and the GFP-TaMYB1A fusion protein was mainly localized in the nucleus of the N. benthamiana epidermal cells. TaMYB1A has transcriptional repressive activity in yeast cells. In this study, TaMYB1A-overexpressed transgenic Arabidopsis lines were generated to elucidate the effect of overexpression of TaMYB1A on the biosynthesis of lignin and flavonoid. Our results suggested that overexpression of TaMYB1A inhibited the plant height (P < 0. 05) and decreased the lignin (P < 0. 05) and flavonoid (P < 0. 05) biosynthesis of the transgenic Arabidopsis plants significantly. TaMYB1A could bind to the promoters of the Arabidopsis At4CL1, AtC4H, AtC3H, and AtCHS as well as the wheat Ta4CL1 and TaC4H1 revealed by yeast one-hybrid (Y1H) assasy, the transcriptional repressive effect of TaMYB1A on At4CL1, AtC4H, AtC3H, and AtCHS was confirmed by dual-luciferase reporter systems and also on Ta4CL1 and TaC4H1 by a genetic approach. Gene chip and quantitative RT-PCR (qRT-PCR) results showed that overexpression of TaMYB1A down-regulated the expression of most of the key genes involved in the phenylpropanoid metabolism and decreased the 4CL activity (P < 0. 05) of the transgenic Arabidopsis plants significantly. As suggested above, the wheat TaMYB1A belongs to the subgroup 4 R2R3 MYB transcription factors. TaMYB1A could bind to the promoters of the key genes involved in phenylpropanoid metabolism, repress their expression and negatively regulate the phenylpropanoid metabolism pathway and plant height.

Optimization of radiological protection of patients undergoing digital radiography / 中华放射医学与防护杂志

Objective To identify the necessity to carry out optimization procedure in routine digital radiography (DR) by evaluating changes of patient radiation dose and image waste ratio before and after optimization.Methods Two hundred patients with near-standard body build were enrolled in the study.Half of them undertook routine examination,and the others undertook the examination with bestlyoptimized protocol.The dose-area product (DAP) and entrance surface dose (ESD) were recorded.The image waste ratios in 2 groups were calculated and the reasons for image waste were analyzed.The radiation dose and image waste ratio before and after optimization were compared.Results The ESD,DAP and image waste ratio in bestly-optimized radiography were significantly lower than those in non-optimized radiography (z =9.31,16.22,P＜0.05; x2 =36.5,P ＜ 0.05).Conclusion Using the bestlyoptimized digital radiography,the patient radiation dose and image waste ratio are effectively reduced.

Factors influencing the choice of atrial septal occluder for transcatheter closure of secundum atrial septal defects / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze factors influencing the choice of atrial septal occluder (ASO) for transcatheter closure of patients with secundum atrial septal defect (ASD).</p><p><b>METHODS</b>A total of 1114 ASD patients [388 males, aged from 2 to 75 years, mean age (26.3 +/- 17.0) years] were enrolled. Patients were divided to adult (> 14 years, mean 34.4 years, n = 779) and child (< or = 14 years, mean 7.3 years, n = 335) groups. ASD size in different ultrasound cross-sections was determined by transthoracic echocardiography (TTE). ASO size was chosen on the basis of the maximum diameter of the defect (MD). Defect-shapes and rim lengths of ASD, the difference choice of ASO in the two groups were compared.</p><p><b>RESULTS</b>MD of the defects ranged from 5 to 40 mm [mean (19.7 +/- 7.8) mm]. ASD was successfully occluded in 1085 out of 1114 patients (97.4%). Occluder size ranged from 6 to 46 mm [mean (25.8 +/- 8.9) mm] and the difference between occluder size and MD ranged from 2 to 10 mm [mean (6.1 +/- 3.4) mm, ASO/MD ratio 1.3:1]. Though the diameter of the defect was similar between the 2 groups, the size of occluder was significantly larger in adult group than that in child group (ASO/MD ratio 1.1 - 1.6:1 vs. 1.2 - 1.8:1, P < 0.05). MD was significantly correlated with ASO in both groups (r = 0.911 and r = 0.944 in adults and child groups, respectively, all P < 0.01). The size and increment of the occluder used in patients with deficient anterior rims was significantly bigger than patients with sufficient anterior rims (P < 0.01).</p><p><b>CONCLUSION</b>The maximum diameter of the defect was the major determinant for selecting occluder size and choice of occluder size was also influenced by patient age, defect-shape and defect rim for transcatheter closure of secundum ASD.</p>