Overexpression of microRNA-99a Attenuates Cardiac Hypertrophy

Pathological cardiomyocyte hypertrophy is associated with significantly increased risk of heart failure, one of the leading medical causes of mortality worldwide. MicroRNAs are known to be involved in pathological cardiac remodeling. However, whether miR-99a participates in the signaling cascade leading to cardiac hypertrophy is unknown. To evaluate the role of miR-99a in cardiac hypertrophy, we assessed the expression of miR-99a in hypertrophic cardiomyocytes induced by isoprenaline (ISO)/angiotensin-II (Ang II) and in mice model of cardiac hypertrophy induced by transverse aortic constriction (TAC). Expression of miR-99a was evaluated in these hypertrophic cells and hearts. We also found that miR-99a expression was highly correlated with cardiac function of mice with heart failure (8 weeks after TAC surgery). Overexpression of miR-99a attenuated cardiac hypertrophy in TAC mice and cellular hypertrophy in stimuli treated cardiomyocytes through down-regulation of expression of mammalian target of rapamycin (mTOR). These results indicate that miR-99a negatively regulates physiological hypertrophy through mTOR signaling pathway, which may provide a new therapeutic approach for pressure-overload heart failure.     

Time-Staged Gamma Knife Stereotactic Radiosurgery for Large Cerebral Arteriovenous Malformations: A Preliminary Report

ObjectiveWe retrospectively analyzed our experience with time-staged gamma knife stereotactic radiosurgery (GKS) in treating large arteriovenous malformation(AVM)s;≥ 10 cm³).MethodsForty-five patients who underwent time-staged GKS (2-stage, n = 37;3-stage,n = 8) between March 1998 and December 2011 were included. The mean volume treated was 20.42±6.29 cm³ (range, 10.20–38.50 cm³). Obliteration rates of AVMs and the associated complications after GKS were evaluated.ResultsMean AVM volume (and median marginal dose) at each GKS session in the 37 patients who underwent 2-stage GKS was 19.67±6.08 cm³ (13 Gy) at session 1 and 6.97±6.92 cm³ (17 Gy) at session 2. The median interval period was 39 months. After follow-up period of 37 months, the complete obliteration rate was 64.9%. The mean AVM volume (and median marginal dose) at each GKS session in the 8 patients who underwent 3-stage GKS was 23.90±6.50 cm³ (12.25 Gy), 19.43±7.46 cm³ (13.5 Gy), 7.48±6.86 cm³ (15.5 Gy) at session 1, 2, and 3, respectively. The median interval duration between each GKS session was 37.5 and 38 months, respectively. After a median follow-up period of 47.5 months, 5 patients (62.5%) achieved complete obliteration. Postradiosurgical hemorrhage developed in 5 patients (11.1%) including one case of major bleeding and 4 cases of minor bleeding. No patient suffered from clinically symptomatic radiation necrosis following radiation.ConclusionTime-staged GKS could be an effective and safe treatment option in the management of large AVMs.     

源自大黄鱼肠道柠檬酸杆菌的外切几丁质酶的特性分析（英文）北大核心CSCD

【目的】从饲喂富含几丁质饲料的大黄鱼肠道分离具有几丁质分解功能的菌株并分离鉴定新的几丁质酶。【方法】利用胶体几丁质平板分离饲喂杂鱼的大黄鱼肠道中的几丁质分解菌。对几丁质酶基因chi-X进行了克隆并在大肠杆菌中表达。对CHI-X的酶学性质进行了分析。【结果】从饲喂杂鱼的大黄鱼肠道内容物中分离出1株具有几丁质分解功能的费氏柠檬酸杆菌,其中的几丁质酶基因编码1个含493个氨基酸残基的蛋白,其中包含一个糖苷水解酶18家族催化域。CHI-X对胶体几丁质具有分解功能。最适p H和温度分别是4.0和60°C。CHI-X具有很强的pH稳定性,在pH 3.0–11.0的范围培育1 h仍保留90%左右的活性。Mn^(2+),Li^+和K^+可促进CHI-X酶活,Ag^+对CHI-X有抑制作用。CHI-X对蛋白酶和石斑鱼肠道内容物有较强的抗逆性。CHI-X可分解胶体几丁质为N-乙酰葡萄糖胺和N-乙酰葡萄糖胺二聚体,表明它是一个几丁质外切酶。最后,CHI-X和另一个几丁质酶Chi565表现出酶活性的加和效应。【结论】分离自肠道菌的CHI-X能很好适应海水鱼类的肠道环境,可以作为温水海水养殖鱼类的饲料添加剂使用。     

荧光蛋白标签对gD囊膜蛋白在BHK-21细胞亚细胞定位的影响

【目的】探究荧光蛋白标签对马疱疹病毒I型(Equine herpes virus type 1,EHV-1)gD囊膜蛋白亚细胞定位的影响。【方法】以EHV-1基因组为模板利用PCR扩增gD全基因,分别克隆至pAcGFP1-C1和p Ds Red2-N1质粒,构建p Ac-GFP-gD(GFP-gD)和p Ds-gD-Red(gD-Red)重组质粒;将GFP基因插入gD基因信号肽序列之后并克隆至PVAX-1质粒,构建PVAX-S-GFP-gD’(S-GFP-gD’)重组质粒;将Flag标签序列与gD囊膜蛋白N端序列融合后并克隆至p VAX-1表达载体,构建p VAX-Flag-gD(Flag-gD)重组质粒。将4种不同重组真核表达质粒分别转染BHK-21细胞,通过激光共聚焦显微镜对不同融合蛋白gD进行亚细胞定位。【结果】成功构建4种不同的融合蛋白gD真核表达载体;在BHK-21细胞单独表达时,不同融合蛋白gD绝大部分都定位于高尔基体,极少量定位于细胞核内。【结论】不同插入位点的荧光蛋白标签对gD囊膜蛋白亚细胞定位无明显影响,这对今后研究其它蛋白亚细胞定位提供参考。     

一种具有高β-葡聚糖酶活性的几丁质外切酶基因的克隆、表达和性质鉴定

【目的】表达并鉴定来源于维氏气单胞菌的几丁质酶Chi92并研究其作为水产饲用酶的有效性。【方法】自A.veronii B565中克隆chi92基因并在Pichia pastoris GS115中进行表达,对表达成功的Chi92进行分离纯化和生化鉴定。最后将Chi92添加到含有毕赤酵母粉的饲料中饲喂斑马鱼2周,研究Chi92添加对斑马鱼生长、饲料利用率、肠道微绒毛形态和抗病性能的影响。【结果】chi92基因编码具有864个氨基酸残基的多肽。Chi92在p H 6.0和40°C时表现最佳酶活。Chi92对蛋白酶有抗性,同时酶活不受金属离子显著影响。Chi92具备高几丁质酶活(69.4 U/m L)。以胶体几丁质和β-1,3-1,4-葡聚糖作为底物时,比活力分别为809.2 U/mg和235.6 U/mg。薄层层析和电喷雾电离质谱联用技术均表明N-乙酰葡糖胺二聚体是Chi92酶解胶体几丁质的主要产物。Chi92在对酵母细胞壁的降解方面比其他几丁质酶性能更加优良。经过2周饲喂,添加有Chi92的饲料显著提高了斑马鱼肠道微绒毛的高度和密度,同时斑马鱼的生长,饲料利用率,以及抗病性能均得到了一定提高。【结论】Chi92具有p H稳定性、抗逆性和高酵母细胞壁降解功能,能较好地作为饲用酶用于温水水产养殖。     

Transformation from Organo-Cr (III) to Trivalent Chromium Mineral (Guyanaite/Grimaldiite) and its Environmental Implication

Remediation of heavy-metal contamination by biomineralization has become an environmentally very important issue in the last two decades. Here we describe the transformation of amorphous organo-Cr(III) to chromium hydroxide oxide (guyanaite/grimaldiite) by hydrothermal treatment (HTT). First, glycine-Cr(III) was synthesized to serve as a simple model for exploring the conditions favoring HTT. Cell-bound Cr(III) was obtained by the reduction of hexavalent chromium [Cr(VI)] to trivalent chromium [Cr(III)] by Bacillus cereus. Then the reduced Cr(III) was chelated by ligands at the cell surface, forming cell-bound Cr(III). Subsequently, HTT was applied to treat cell-bound Cr(III) at different temperatures and for different lengths of time. The results showed that, by this treatment at 200°C for 7 days or at 250°C for 1 day, glycine-Cr(III) was converted to trivalent chromium mineral (guyanaite/grimaldiite), having the form of nanosheets with a length of 10～20 nm and a width of 3～5 nm under the described conditions. Cell-bound Cr(III) could also be converted to guyanaite/grimaldiite at 250°C for 9 days if it was bound by an organic compound more complex than glycine. Our finding showed that organo-Cr(III) could be transformed into minerals by an appropriate hydrothermal process, which is applicable to bioremediation of heavy-metal pollution. Our findings also suggest that organo-Cr(III) may play an important role in the biogeochemistry of chromium.     

Dual‐function fluorescent probe for cancer imaging and therapy

To date, several fluorescent probes modified by a single targeting agent have been explored. However, studies on the preparation of dual‐function quantum dot (QD) fluorescent probes with dual‐targeting action and a therapeutic effect are rare. Here, a dual‐targeting CdTe/CdS QD fluorescent probe with a bovine serum albumin–glycyrrhetinic acid conjugate and arginine‐glycine‐aspartic acid was successfully prepared that could induce the apoptosis of liver cancer cells and showed enhanced targeting in in vitro cell imaging. Therefore, the as‐prepared fluorescent probe in this work is an efficient diagnostic tool for the simultaneous detection of liver cancer and breast cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.     

Carbon storage and potentials of the broad-leaved forest in alpine region of the Qinghai-Xizang Plateau,China北大核心CSCD

Aims Our objective was to explore the vegetation carbon storages and their variations in the broad-leaved forests in the alpine region of the Qinghai-Xizang Plateau that includes Qinghai Province and Xizang Autonomous Region. Methods Based on forest resource inventory data and field sampling, this paper studied the carbon storage, its sequestration rate, and the potentials in the broad-leaved forests in the alpine region of the Qinghai-Xizang Plateau. Important findings The vegetation carbon storage in the broad-leaved forest accounted for 310.70 Tg in 2011, with the highest value in the broad-leaved mixed forest and the lowest in Populus forest among the six broad-leaved forests that include Quercus, Betula, Populus, other hard broad-leaved species, other soft broad-leaved species, and the broadleaved mixed forest. The carbon density of the broad-leaved forest was 89.04 Mg•hm2, with the highest value in other hard broad-leaved species forest and the lowest in other soft broad-leaved species forest. The carbon storage and carbon density in different layers of the forests followed a sequence of overstory layer > understory layer > litter layer > grass layer > dead wood layer, which all increased with forest age. In addition, the carbon storage of broad-leaved forest increased from 304.26 Tg in 2001 to 310.70 Tg in 2011. The mean annual carbon sequestration and its rate were 0.64 Tg•a1 and 0.19 Mg•hm2•a1, respectively. The maximum and minimum of the carbon sequestration rate were respectively found in other soft broad-leaved species forest and other hard broad-leaved species forest, with the highest value in the mature forest and the lowest in the young forest. Moreover, the carbon sequestration potential in the tree layer of broad-leaved forest reached 19.09 Mg•hm2 in 2011, with the highest value found in Quercus forest and the lowest in Betula forest. The carbon storage increased gradually during three inventory periods, indicating that the broad-leaved forest was well protected to maintain a healthy growth by the forest protection project of Qinghai Province and Xizang Autonomous Region.     

氰酸盐诱导氧化应激促进肾小管上皮细胞上皮–间充质转化

该研究探讨氰酸盐(cyanate)诱导肾小管上皮细胞氧化应激损伤和促进肾纤维化的作用。氰酸盐作用HK-2肾小管上皮细胞后, CCK8法检测其对细胞活力的影响;倒置显微镜观察细胞形态的改变; DCFH-DA法检测细胞ROS水平;细胞免疫荧光和Western blot分别检测E-cadherin、Fibronectin、α-SMA的表达; Western blot检测TGF-β的表达水平。结果显示, 2 mmol/L氰酸盐明显下调HK-2细胞的活力(P<0.05),细胞形态变为长梭形。氰酸盐作用24 h后, HK-2细胞内ROS水平呈浓度依赖性升高。免疫荧光和Western blot结果均显示,氰酸盐作用24 h后, HK-2的Fibronectin、α-SMA表达升高, E-cadherin表达下降; TGF-β的表达水平随氰酸盐浓度升高而上调(P<0.05)。以上结果表明,氰酸盐诱导肾小管上皮细胞产生过量ROS,上调TGF-β水平促进细胞上皮–间充质细胞转化(epithelia-mesenchymal transition, EMT)。