RhNRG-1β Protects the Myocardium against Irradiation-Induced Damage via the ErbB2-ERK-SIRT1 Signaling Pathway

Radiation-induced heart disease (RIHD), which is a serious side effect of the radiotherapy applied for various tumors due to the inevitable irradiation of the heart, cannot be treated effectively using current clinical therapies. Here, we demonstrated that rhNRG-1β, an epidermal growth factor (EGF)-like protein, protects myocardium tissue against irradiation-induced damage and preserves cardiac function. rhNRG-1β effectively ameliorated irradiation-induced myocardial nuclear damage in both cultured adult rat-derived cardiomyocytes and rat myocardium tissue via NRG/ErbB2 signaling. By activating ErbB2, rhNRG-1β maintained mitochondrial integrity, ATP production, respiratory chain function and the Krebs cycle status in irradiated cardiomyocytes. Moreover, the protection of irradiated cardiomyocytes and myocardium tissue by rhNRG-1β was at least partly mediated by the activation of the ErbB2-ERK-SIRT1 signaling pathway. Long-term observations further showed that rhNRG-1β administered in the peri-irradiation period exerts continuous protective effects on cardiac pump function, the myocardial energy metabolism, cardiomyocyte volume and interstitial fibrosis in the rats receiving radiation via NRG/ErbB2 signaling. Our findings indicate that rhNRG-1β can protect the myocardium against irradiation-induced damage and preserve cardiac function via the ErbB2-ERK-SIRT1 signaling pathway.     

Magnesium enhances aluminum-induced citrate secretion in rice bean roots (Vigna umbellata) by restoring plasma membrane H+-ATPase activity

We demonstrated that magnesium (Mg) can alleviate aluminum (Al) toxicity in rice bean [Vigna umbellata (Thunb.) Ohwi & Ohashi] more effectively than is expected from a non-specific cation response. Micromolar concentrations of Mg alleviated the inhibition of root growth by Al but not by lanthanum, and neither strontium nor barium at the micromolar level alleviates Al toxicity. Aluminum also induced citrate efflux from rice bean roots, and this response was stimulated by inclusion of 10 microM Mg in the treatment solution. The increase in the Al-induced citrate efflux by Mg paralleled the improvement in root growth, suggesting that the ameliorative effect of Mg might be related to greater citrate efflux. Vanadate (an effective H+-ATPase inhibitor) decreased the Al-induced citrate efflux, while addition of Mg partly restored the efflux. Mg addition also increased the activity of Al-reduced plasma membrane H+-ATPase, as well as helping to maintain the Mg and calcium contents in root apices. We propose that the addition of Mg to the toxic Al treatment helps maintain the tissue Mg content and the activity of the plasma membrane H+-ATPase. These changes enhanced the Al-dependent efflux of citrate which provided extra protection from Al stress.     

Genetic diversity in Chinese modern wheat varieties revealed by microsatellite markers

Genetic diversity of 1680 modern varieties in Chinese candidate core collections was analyzed at 78 SSR loci by fluorescence detection system. A total of 1336 alleles were detected, of which 1253 alleles could be annotated into 71 loci. For these 71 loci, the alleles ranged from 4 to 44 with an average of 17.6, and the PIC values changed from 0.19 to 0.89 with an average of 0.69. (1) In the three genomes of wheat, the average genetic richness was B>A>D, and the genetic diversity indexes were B>D>A. (2) Among the seven homoeologous groups, the average genetic richness was 2=7>3>4>6>5>1, and the genetic diversity indexes were 7>3>2>4>6>5>1. As a whole, group 7 possessed the highest genetic diversity, while groups 1 and 5 were the lowest. (3) In the 21 wheat chromosomes, 7A, 3B and 2D possessed much higher genetic diversity, while 2A, 1B, 4D, 5D and 1D were the lowest. (4) The highest average genetic diversity index existed in varieties bred in the 1950s, and then it declined continually. However, the change tendency of genetic diversity among decades was not greatly sharp. This was further illustrated by changes of the average genetic distance between varieties. In the 1950s it was the largest (0.731). Since the 1960s, it has decreased gradually (0.711, 0.706, 0.696, 0.695). The genetic base of modern varieties is becoming narrower and narrower. This should be given enough attention by breeders and policy makers.     

日本血吸虫中国大陆株TPI基因的克隆及其表达产物特性

磷酸丙糖异构酶（ＴＰＩ）是血吸虫病疫苗重要的候选抗原基因之一。参考日本血吸虫已发表的ＴＰＩｃＤＮＡ序列,以日本血吸虫中国大陆株成虫ｍＲＮＡ为模板,用ＲＴ－ＰＣＲ法快速克隆出一大小约８００ｂｐ的ＤＮＡ片段。ＤＮＡ序列分析证实,所扩增到的ＤＮＡ片段即为日本血吸虫中国大陆株磷酸丙糖异构酶（ＳｊＴＰＩｃ）基因。将该基因重组到表达型质粒ｐＧＥＸ－４Ｔ中,表达的ＧＳＴ融合蛋白分子量约５４ｋＤ。用谷胱甘肽琼脂糖凝胶亲和层析柱纯化的重组蛋白不仅纯度好,而且得率高,纯化产量可达３０ｍｇ／Ｌ培养物。免疫试验结果表明该重组蛋白具有良好的抗原性,是一种较为理想的抗原分子。     

限制性内切酶EcoR的高效表达与纯化

Eco R 是最早被发现的需要底物 DNA分子上至少有两个识别序列 [CCWGG(W=A/ T) ]才显示酶活性的 类限制酶 [1 ] .这种底物要求类似于位点特异性重组和转座有关的酶类 [2 ,3 ] .最近有人 [4]提出 Eco R 的两个亚基与 DNA上两个识别序列相互作用形成活性复合体的动态模式 ,但对其如何识别底物以及如何行使水解功能等实质性问题仍不清楚 .高纯度 Eco R 限制酶的制备 ,不仅具有较高的应用价值 ,也为进一步研究该酶与核酸特殊的作用机制和功能打下良好基础 .Eco R 基因的克隆和表达已有报道 [5 ,6 ] .国外对 Eco R 的制备仍存在表…     

Cloning, sequencing and analysis of a gene encoding Escherichia coli proline dehydrogenase

Abstract Using a genomic subtraction technique, we cloned a DNA sequence that is present in wild-type Escherichia coli strain CSH4 but is missing in a presumptive proline dehydrogenase deletion mutant RM2. Experimental evidence indicated that the cloned fragment codes for proline dehydrogenase (EC 1.5.99.8) since RM2 cells transformed with a plasmid containing this sequence was able to survive on minimal medium supplemented with proline as the sole nitrogen and carbon sources. The cloned DNA fragment has an open reading frame of 3942 bp and encodes a protein of 1313 amino acids with a calculated M _r of 143 808. The deduced amino acid sequence of the E. colli proline dehydrogenase has an 84.9% homology to the previously reported Salmonella typhimurium putA gene but it is 111 amino acids longer at the C-terminal than the latter.     

Extremely Flexible Transparent Conducting Electrodes for Organic Devices

Extremely flexible transparent conducting electrodes are developed using a combination of metal‐embedding architecture into plastic substrate and ultrathin transparent electrodes, which leads to highly transparent (optical transmittance ≈93% at a wavelength of 550 nm), highly conducting (sheet resistance ≈13 Ω □^?1), and extremely flexible (bending radius ≈ 200 μm) electrodes. The electrodes are used to fabricate flexible organic solar cells and organic light‐emitting diodes that exhibit performance similar or superior to that of devices fabricated on glass substrates. Moreover, the flexible devices do not show degradation in their performance even after being folded with a radius of ≈200 μm.