奇异果甜蛋白及其基因工程

奇异果甜蛋白(thaumatin)是迄今为止最甜的物质之一,对其研究具有很重要的意义。奇异果甜蛋白的生化性质基本清楚,基因序列和氨基酸序列都已测定。它的甜味可能是由奇异果甜蛋白上特定基团和受体结合引起的。对奇异果甜蛋白的生理功能知之甚少。近二十年来,在奇异果甜蛋白的基因工程上取得了一定进展,但仍然存在许多困难。 Abstract:Thaumatin is one of the sweetest substances known to date,it is important to study the thaumatin.The biochemical properties of thaumatin have been clarified clearly.Thaumatin had been isolated and sequenced.The mechanism of the sweetness of thaumatin may be due to the combination of some special groups and the receptors.The exact function of thaumatin is still not clear.Although gene engineering of thaumatin has been carried out for 20 years,there are still some difficulties to be solved for using in the market.     

Insights into the fluoride-resistant regulation mechanism of <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis> ATCC 23270 based on whole genome microarrays

Acidophilic microorganisms involved in uranium bioleaching are usually suppressed by dissolved fluoride ions, eventually leading to reduced leaching efficiency. However, little is known about the regulation mechanisms of microbial resistance to fluoride. In this study, the resistance of Acidithiobacillus ferrooxidans ATCC 23270 to fluoride was investigated by detecting bacterial growth fluctuations and ferrous or sulfur oxidation. To explore the regulation mechanism, a whole genome microarray was used to profile the genome-wide expression. The fluoride tolerance of A. ferrooxidans cultured in the presence of FeSO₄ was better than that cultured with the S⁰ substrate. The differentially expressed gene categories closely related to fluoride tolerance included those involved in energy metabolism, cellular processes, protein synthesis, transport, the cell envelope, and binding proteins. This study highlights that the cellular ferrous oxidation ability was enhanced at the lower fluoride concentrations. An overview of the cellular regulation mechanisms of extremophiles to fluoride resistance is discussed.     

Synthesis of 2H-benzo[b][1,4]oxazin-3(4H)-one derivatives as platelet aggregation inhibitors

Novel 2H-benzo[b][1,4]oxazin-3(4H)-ones have been synthesized by condensation, reduction, O-alkylation and Smiles rearrangement using 3-bromo-4-hydroxy benzaldehyde, anilines, and chloroacetyl chloride as starting materials. All the synthesized compounds have been characterized by (1)H NMR, (13)C NMR, and HRMS, and tested for the inhibitory ability on platelet aggregation. The results have shown that the ADP (adenosine 5'-diphosphate)-induced platelet aggregation was inhibited by 7a-g with the IC(50) value at 10.14-18.83 μmol/L. Compound 7a exhibited the most potent inhibitory effect (IC(50)=10.14 μmol/L) among all the compounds, but less potent than the control drug ticlopidine (3.18 μmol/L) and aspirin (6.07 μmol/L). The preliminary structure-activity relationship (SAR) was initially investigated in the study.     

Positive Selection of CAG Repeats of the ATXN2 Gene in Chinese Ethnic Groups

The ataxin-2 （ATXN2） gene is located on human chromo-some 12q24.1. In normal individuals, the coding region in exon 1 of this gene has fewer than 31 CAG repeats （Yu et al., 2005： Laffita-Mesa et al., 2012）. However, an abnormal expansion of CAG trinucleotide repeats results in the aggre-gation of polyglutamine （polyQ）, which causes spinocer-ebellar ataxia type 2 （SCA2） （Pulst et al., 1996）. The expanded alleles have more than 32 repeats in the affected individuals, and generally there is an inverse correlation between CAG repeat length and age of onset （Pulst et al., 1996）. SCA2 is an autosomal dominant inheritance neurodegenerative disease, whose major clinical feature is progressive cerebellar ataxia. Atrophies of the brainstem and frontal lobe have been frequently detected by magnetic resonance imaging （MRI） （Yamamoto-Watanabe et al., 2010）. This disease has the strong effect on sensory and motor control.     

Moderate mechanical stimulation rescues degenerative annulus fibrosus by suppressing caveolin-1 mediated pro-inflammatory signaling pathway

Mechanical loading can induce or antagonize the extracellular matrix (ECM) synthesis, proliferation, migration, and inflammatory responses of annulus fibrosus cells (AFCs), depending on the loading mode and level. Caveolin-1 (Cav1), the core protein of caveolae, plays an important role in cellular mechanotransduction and inflammatory responses. In the present study, we presented that AFCs demonstrated different behaviors when subjected to cyclic tensile strain (CTS) for 24 h at a magnitude of 0%, 2%, 5% and 12%, respectively. It was found that 5% CTS had positive effects on cell proliferation, migration and anabolism, while 12% CTS had the opposite effects. Besides, cells exposed to interleukin-1β stimulus exhibited an increase expression in inflammatory genes, and the expression of these genes decreased after exposure to moderate mechanical loading with 5% CTS. In addition, 5% CTS decreased the level of Cav1 and integrin β1 and exhibited anti-inflammatory effects. Moreover, the expression of integrin β1 and p-p65 increased in AFCs transfected with Cav1 plasmids. In vivo results revealed that moderate mechanical stimulation could recover the water content and morphology of the discs. In conclusion, moderate mechanical stimulation restrained Cav1-mediated signaling pathway and exhibited anti-inflammatory effects on AFCs. Together with in vivo results, this study expounds the underlying molecular mechanisms on the effect of moderate mechanical stimulation on intervertebral discs (IVDs) and may provide a new therapeutic strategy for the treatment of IVD degeneration.     

靶向AXL克服肺腺癌EGFR-TKIs获得性耐药

目的:探索AXL在肺腺癌细胞(Lung adenocarcinoma cell, LAC)EGFR-TKIs获得性耐药中的作用,为肺癌临床治疗和新型药物的研发提供实验依据。方法:构建EGFR-TKIs获得性耐药的肺腺癌模型并通过CCK-8法检测耐药株对肺腺癌靶向治疗药物吉非替尼(Gefitinib)、厄洛替尼(Erlotinib)和奥希替尼(Osimertinib)的敏感性。基于基因组学分析筛选出潜在的克服耐药的靶点AXL,通过Western blot和qRT-PCR技术检测AXL的表达情况,并同时检测上皮-间质转化(Epithelial-mesenchymal transition,EMT)分子标志物。R428是AXL的小分子抑制剂,通过CCK-8法、Transwell以及划痕实验等探究靶向AXL对肺腺癌亲本及耐药株增殖和迁移能力的影响。结果:AXL在构建的耐药株中显著高表达,其蛋白表达水平上调15-20倍(P0.001),m RNA水平上调2-5倍(P0.01);EGFR-TKIs耐药株发生上皮间质转化(EMT);靶向AXL选择性抑制耐药株的增殖能力并且恢复了耐药株对EGFR-TKIs的敏感性(P0.001);靶向AXL显著抑制耐药株增强的迁移能力,与亲本株相比最高抑制率可达80%左右(P0.001)。结论:用遗传学和药理学手段靶向AXL可以显著逆转肺腺癌对EGFR-TKIs耐药,逆转耐药株所增强的迁移等肿瘤生物学特征,对克服EGFR-TKIs获得性耐药有着重要的临床治疗价值以及转化医学前景。     

沙地樟子松带状混交林土壤碳氮磷化学计量特征

探究不同沙地樟子松混交林土壤碳氮磷化学计量变化规律,为其混交经营提供科学依据.以沙地樟子松纯林为对照,在沙地樟子松×榆树及沙地樟子松×怀槐带状混交林中,沿沙地樟子松和伴生树种两个方向在距离混交中心0、1、2、3和4 m处的不同土层采集土样,分析土壤有机C、全N、全P、速效N、速效P含量及其计量比的特征.结果表明: 沙地樟子松混交林土壤有机C、全N和速效N含量高于纯林, 沙地樟子松与榆树混交主要增加了深层土壤有机C和全N含量,以及C/N和C/P, 沙地樟子松与怀槐混交提高了土壤N含量, 降低了P含量.随着远离混交林中心,沙地樟子松×榆树混交林中沙地樟子松林带的土壤C/N先升高后降低,全P和速效P含量下降,N/P增加;榆树林带土壤C/N下降,速效P含量先升高后降低.沙地樟子松×怀槐混交林土壤全N含量在沙地樟子松林带先降低后升高,在怀槐林带先升高后降低.沙地樟子松混交林提高了土壤C、N储量,沙地樟子松应与榆树行间混交,与怀槐间隔2行混交.     

24份甜樱桃材料自交不亲和S基因型鉴定

甜樱桃品种绝大部分自交不亲和,限制了甜樱桃的正确评价和合理利用,因此自交不亲和基因型的鉴定对于生产具有重要意义。以24个甜樱桃主栽品种为材料,用5对蔷薇科李属引物组合对24个甜樱桃品种进行了S等位基因的PCR扩增,克隆S基因的扩增片段,用核酸序列在Gen Bank上搜索,确定了5种S基因的核酸序列和大小。结果表明:Pru C2+Pru C4R引物组合扩增效果最好;在琼脂糖凝胶上位置相同的扩增带其核酸序列相同,是同一种S基因;5种S基因扩增片段的大小分别是S1为800 bp,S3为762 bp,S4为962bp,S5为300 bp,S6为456 bp,S9为650 bp;24个甜樱桃S基因型是红手球、早红宝石为S1S3,拉宾斯S1S4',红宝石S1S6,布鲁克斯S1S9,那翁S3S4,秦林、泰安大紫、先锋、早大果、丽珠、美早、5-106、左滕锦、桑提娜为S3S6,黑珍珠、红灯、萨米脱、秦樱为S3S9,胜利为S5S9,明珠、红蜜、雷尼、滨库为S6S9。     

Association between APOC1 Polymorphism and Alzheimer’s Disease: A Case-Control Study and Meta-Analysis

Background

Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer’s disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations.

Methods

To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies.

Results

Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ² = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01).

Conclusions

The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD.