Disruption of microRNA Biogenesis Confers Resistance to ER Stress-Induced Cell Death Upstream of the Mitochondrion

Global downregulation of microRNAs (miRNAs) is a common feature of human tumors and has been shown to enhance cancer progression. Several components of the miRNA biogenesis machinery (XPO5, DICER and TRBP) have been shown to act as haploinsufficient tumor suppressors. How the deregulation of miRNA biogenesis promotes tumor development is not clearly understood. Here we show that loss of miRNA biogenesis increased resistance to endoplasmic reticulum (ER) stress-induced cell death. We observed that HCT116 cells with a DICER hypomorphic mutation (Exn5/Exn5) or where DICER or DROSHA were knocked down were resistant to ER stress-induced cell death. Extensive analysis revealed little difference in the unfolded protein response (UPR) of WT compared to Exn5/Exn5 HCT116 cells upon ER stress treatment. However, analysis of the intrinsic apoptotic pathway showed that resistance occurred upstream of the mitochondria. In particular, BAX activation and dissipation of mitochondrial membrane potential was attenuated, and there was altered expression of BCL-2 family proteins. These observations demonstrate a key role for miRNAs as critical modulators of the ER stress response. In our model, downregulation of miRNA biogenesis delays ER stress-induced apoptosis. This suggests that disrupted miRNA biogenesis may contribute to cancer progression by inhibiting ER stress-induced cell death.     

Single Intraperitoneal Injection of Monocrotaline as a Novel Large Animal Model of Chronic Pulmonary Hypertension in Tibet Minipigs

Objective

The purpose of this study was to establish an animal model of chronic pulmonary hypertension with a single-dose intraperitoneal injection of monocrotaline (MCT) in young Tibet minipigs, so as to enable both invasive and noninvasive measurements and hence facilitate future studies.

Methods

Twenty-four minipigs (8-week-old) were randomized to receive single-dose injection of 12.0 mg/kg MCT (MCT group, n = 12) or placebo (control group, n = 12 each). On day 42, all animals were evaluated for pulmonary hypertension with conventional transthoracic echocardiography, right heart catheterization (RHC), and pathological changes. Findings of these studies were compared between the two groups.

Results

At echocardiography, the MCT group showed significantly higher pulmonary arterial mean pressure (PAMP) compared with the controls (P<0.001). The pulmonary valve curve showed v-shaped signals with reduction of a-waves in minipigs treated with MCT. In addition, the MCT group had longer pulmonary artery pre-ejection phases, and shorter acceleration time and ejection time. RHC revealed higher mean pulmonary arterial pressure (mPAP) in the MCT group than in the control group (P<0.01). A significant and positive correlation between the mPAP values and the PAMP values (R = 0.974, P<0.0001), and a negative correlation between the mPAP and ejection time (R = 0.680, P<0.0001) was noted. Pathology demonstrated evidence of pulmonary vascular remodeling and higer index of right ventricular hypertrophy in MCT-treated minipigs.

Conclusion

A chronic pulmonary hypertension model can be successfully established in young minipigs at six weeks after MCT injection. These minipig models exhibited features of pulmonary arterial hypertension that can be evaluated by both invasive (RHC) and noninvasive (echocardiography) measurements, and may be used as an easy and stable tool for future studies on pulmonary hypertension.     

Effects of Forest Age on Soil Autotrophic and Heterotrophic Respiration Differ between Evergreen and Deciduous Forests

We examined the effects of forest stand age on soil respiration (SR) including the heterotrophic respiration (HR) and autotrophic respiration (AR) of two forest types. We measured soil respiration and partitioned the HR and AR components across three age classes ∼15, ∼25, and ∼35-year-old Pinus sylvestris var. mongolica (Mongolia pine) and Larix principis-rupprechtii (larch) in a forest-steppe ecotone, northern China (June 2006 to October 2009). We analyzed the relationship between seasonal dynamics of SR, HR, AR and soil temperature (ST), soil water content (SWC) and normalized difference vegetation index (NDVI, a plant greenness and net primary productivity indicator). Our results showed that ST and SWC were driving factors for the seasonal dynamics of SR rather than plant greenness, irrespective of stand age and forest type. For ∼15-year-old stands, the seasonal dynamics of both AR and HR were dependent on ST. Higher Q₁₀ of HR compared with AR occurred in larch. However, in Mongolia pine a similar Q₁₀ occurred between HR and AR. With stand age, Q₁₀ of both HR and AR increased in larch. For Mongolia pine, Q₁₀ of HR increased with stand age, but AR showed no significant relationship with ST. As stand age increased, HR was correlated with SWC in Mongolia pine, but for larch AR correlated with SWC. The dependence of AR on NDVI occurred in ∼35-year-old Mongolia pine. Our study demonstrated the importance of separating autotrophic and heterotrophic respiration components of SR when stimulating the response of soil carbon efflux to environmental changes. When estimating the response of autotrophic and heterotrophic respiration to environmental changes, the effect of forest type on age-related trends is required.     

转PvPGIP2基因小麦的获得与纹枯病抗性鉴定

多聚半乳糖醛酸酶抑制蛋白(PGIP)是一种植物防卫蛋白,可阻止一些病原真菌的侵害。本研究克隆出扁豆PvP-GIP2基因编码序列,构建了受玉米泛素(ubiquitin)启动子控制的PvPGIP2基因表达载体pA25-PvPGIP2;采用基因枪法将pA25-PvPGIP2转化小麦推广品种扬麦18幼胚愈伤组织4000块,获得了203株再生植株。PCR检测出阳性植株65株,转化率为1.625%。对转PvPGIP2基因小麦T1～T2植株,进行外源基因的PCR、RT-PCR、荧光定量RT-PCR(Q-RT-PCR)分析和小麦纹枯病抗性鉴定。结果表明,转入的PvPGIP2能够在转基因小麦中遗传、转录与表达;PvPGIP2基因的表达提高了转基因植株对小麦纹枯病的抗性。     

Cyclo-hexa-peptides at the water/cyclohexane interface: a molecular dynamics simulation

Molecular dynamic (MD) simulations have been performed to study the behaviors of ten kinds of cyclo-hexa-peptides (CHPs) composed of amino acids with the diverse hydrophilic/hydrophobic side chains at the water/cyclohexane interface. All the CHPs take the “horse-saddle” conformations at the interface and the hydrophilicity/hydrophobicity of the side chains influences the backbones’ structural deformations. The orientations and distributions of the CHPs at the interface and the differences of interaction energies (ΔΔE) between the CHPs and the two liquid phases have been determined. RDF analysis shows that the H-bonds were formed between the O_C atoms of the CHPs’ backbones and H_w atoms of water molecules. N atoms of the CHPs’ backbones formed the H-bonds or van der Waals interactions with the water solvent. It was found that there is a parallel relationship between ΔΔE and the lateral diffusion coefficients (D _xy ) of the CHPs at the interface. The movements of water molecules close to the interface are confined to some extent, indicating that the dynamics of the CHPs and interfacial water molecules are strongly coupled.

Use of biodiesel‐derived crude glycerol for vancomycin production by Amycolatopsis orientalis XMU‐VS01

Crude glycerol is a primary by‐product in the biodiesel industry. Microbial fermentation on crude glycerol for producing value‐added products provides opportunities to utilize a large quantity of this by‐product. This study investigates the potential of using the crude glycerol to produce vancomycin (glycopeptide antibiotics) through fermentation of Amycolatopsis orientalis XMU‐VS01. The results show that crude glycerol was the most effective carbon source for mycelium growth and vancomycin production, with 40–60 g/L glycerol concentration as optimal range. Among other culture medium components, potato protein (nitrogen source) and the phosphate concentration had significant effects (p<0.05) for vancomycin production. A Box‐Behnken design and response surface methodology were employed to formulate the optimal medium. Their optimal values were determined as 52.73 g/L of glycerol, 17.36 g/L of potato protein, and 0.1 g/L of dipotassium phosphate. A highest vancomycin yield of 7.61 g/L with biomass concentration of 15.8 g/L was obtained after 120 h flask fermentation. The yield of vancomycin was 3.5 times higher than with basic medium. The results suggest that biodiesel‐derived crude glycerol is a promising feedstock for production of vancomycin from A. orientalis culture.     

Tourettesyndrome免疫病因学研究进展

多发性抽动症（Tourette syndrome）是一种慢性神经精神性疾病,好发于儿童和青少年,主要表现为一个或多个部位肌肉运动性或发声性抽动,发作期持续超过一年,间歇期不超过3个月。TS的病因和发病机制至今仍未明确,目前认为其发病与免疫因素,环境心理因素,遗传因素,生物化学因素等多种因素有关,目前,A族B溶血性链球菌与Ts的发生跟发展的关系已有所报道,较多研究是关于链球茵感染的,一些免疫相关研究发现与链球菌感染有关的小儿自身免疫性神经精神疾病会引发或加重抽动症状。另外,过敏性变态反应性疾病与Ts患儿的自身免疫应答活跃的关系也有所报道。神经．内分泌一免疫网络学说认为,外周免疫系统跟中枢神经系统之间,可通过直接接触或通过产生并释放出来的生物活性因子进行信息交流。细胞因子正是两大系统间相互作用的信使,不仅可以调节免疫,而且还可以调控神经元和神经胶质细胞的功能。细胞因子与神经介质、内分泌激素共同组成机体细胞间的信号分子,参与免疫系统并激活神经递质及激素间的信息传递,与精神障碍和心理机体反应密切相关。因此,有关免疫病因学异常可能是部分易感患儿发病的机制,文章从感染免疫学,过敏性变态反应性疾病,以及细胞因子调节网络等与免疫相关的几个方面加以综述。     

38份晾晒烟种质资源遗传关系的SSR分析

利用SSR标记技术对38份晾晒烟种质资源的遗传关系进行了分析。从自己开发的近3000对烟草SSR引物中随机选出30对引物,在38份供试材料中共检测出173个等位基因,每对SSR引物可检测的等位基因数为2~11个,平均为5.77个。38份材料间遗传相似系数（GS）的变化范围为0.165-0.928,平均GS 为0.546。表明38份晾晒烟的遗传多样性丰富,遗传差异较大,亲缘关系较远。聚类分析表明,在L1（GS-0.165）处可将38个品种分为2大类,即晾晒烟类群和美国从烟草起源地收集的烟草（TI：Tobacco Instruction）类群;晾晒烟类群又可进一步分为4组,其聚类结果与所期望的结果基本一致。表明SSR是一种有效、稳定和可靠的分子标记,能较好地从分子水平上揭示烟草(尤其是晾晒烟)种质资源的遗传背景和亲缘关系。     

Unusual lipids and acylglucosylsterols from the roots of Livistona chinensis

A 70% ethanol extract from the roots of Livistona chinensis has been investigated, led to the isolation of 18 compounds, including two new 6′-O-acyl-β-d-glucosyl-β-sitosterols, 6′-O-(2″-hydroxyheptadecanoyl)-β-d-glucosyl-β-sitosterol (1) and 6′-O-(icosa-9″Z,12″Z-dienoyl)-β-d-glucosyl-β-sitosterol (2), two new keto esters, ethyl 16-(dodeca-4″′Z,7″′Z-dienyl)-29-oxo-15-(tetradeca-5″Z,8″Z,11″Z-trienyl) triacontanoate (7), and 16-hydroxy-8-oxohexadecyl tetradecanoate (9), a new unsaturated fatty acid, tetracosa-(11Z,14Z,18Z)-trienoic acid (8), as well as a new fatty alcohol, 10-decylnonadecane-1,19-diol (10). The structures of new compounds were elucidated, based on spectroscopic and chemical methods. The antiproliferative activity against four human tumor cell lines (K562, HL-60, HepG2, and CNE-1) was evaluated. Four compounds (1–3, 5) showed potent antiproliferative effects with the IC₅₀ of 10–100 μM. To our knowledge, this is the first report of the occurrence of 6′-O-acyl-β-d-glucosyl-β-sitosterol and 3-O-acyl-β-sitosterol in the genus Livistona. Keto fatty acids and their esters are also rare in higher plant.     

Flavonoids from the bark and stems of Cassia fistula and their anti-tobacco mosaic virus activities

Two new flavonoids, fistulaflavonoids B and C (1–2), together with five known flavonoids (3–7) were isolated from the bark and stems of Cassia fistula. Their structures were determined by means of HRESIMS, extensive 1D and 2D NMR spectroscopic studies and chemical evidences. The anti-tobacco mosaic virus (anti-TMV) activity of the isolated flavonoids was also evaluated. The results showed that compounds 1 and 2 showed high anti-TMV activity with inhibition rate of 28.5% and 31.3%, which is higher than that of Ningnanmycin (24.7%). Compounds 4–7 showed modest anti-TMV activity with inhibition rate of 18.5%, 22.7%, 16.4%, and 15.3%, respectively.