脊髓灰质炎病毒中Ⅰ9株基因组克隆及其部分结构分析

以脊髓灰质炎病毒RNA为模板,反转录合成了长链ds-cDNA。将合成的脊灰病毒中I9株ds—cDNA片段重组到质粒pAT153上,获得了约占脊灰病毒中I9基因组95％以上的cDNA克隆。对克隆的中I9cDNA部分片段作了限制性内切酶图谱分析和部分核酸的序列分析,发现脊灰病毒中I9部分核酸顺序有所改变。     

川滇生态屏障区景观生态风险评价及影响因素

探究重点生态功能区景观生态风险时空演变特征,揭示人类活动对景观生态风险恶化的潜在影响,对防范和化解景观生态风险、促进区域可持续发展具有重要意义。以2000、2010、2020年土地覆被数据为基础,运用ArcGIS 10.8和Fragstats 4.2等软件,基于景观格局指数和脆弱度指数构建景观生态风险评价模型,借助空间分析方法,揭示川滇生态屏障区景观生态风险时空演变特征,采用地理探测器测度不同区域范围的自然和社会经济因素对景观生态风险的影响。结果表明: 2000—2020年间,研究区人造地表、水体、灌木地面积总体呈上升趋势,林地、耕地、草地、湿地、裸地、冰川永久积雪面积总体呈下降趋势,景观类型转移以林地、草地、耕地间转移为主,其中,耕地转人造地表最显著;景观生态风险平均值有所下降,景观生态风险等级分布与景观类型变化及转移特征较为一致;研究区整体上以低生态风险、较低生态风险和较高生态风险等级为主;景观生态风险的时空演化特征总体受高程、降水等自然因素影响,经济社会及区域可达性对局部风险恶化区的影响较为突出。     

Stimulation of σ1-receptor restores abnormal mitochondrial Ca mobilization and ATP production following cardiac hypertrophy

Background

We previously reported that the σ₁-receptor (σ₁R) is down-regulated following cardiac hypertrophy and dysfunction in transverse aortic constriction (TAC) mice. Here we address how σ₁R stimulation with the selective σ₁R agonist SA4503 restores hypertrophy-induced cardiac dysfunction through σ₁R localized in the sarcoplasmic reticulum (SR).

Methods

We first confirmed anti-hypertrophic effects of SA4503 (0.1–1 μM) in cultured cardiomyocytes exposed to angiotensin II (Ang II). Then, to confirm the ameliorative effects of σ₁R stimulation in vivo, we administered SA4503 (1.0 mg/kg) and the σ₁R antagonist NE-100 (1.0 mg/kg) orally to TAC mice for 4 weeks (once daily).

Results

σ₁R stimulation with SA4503 significantly inhibited Ang II-induced cardiomyocyte hypertrophy. Ang II exposure for 72 h impaired phenylephrine (PE)-induced Ca^2 + mobilization from the SR into both the cytosol and mitochondria. Treatment of cardiomyocytes with SA4503 largely restored PE-induced Ca^2 + mobilization into mitochondria. Exposure of cardiomyocytes to Ang II for 72 h decreased basal ATP content and PE-induced ATP production concomitant with reduced mitochondrial size, while SA4503 treatment completely restored ATP production and mitochondrial size. Pretreatment with NE-100 or siRNA abolished these effects. Chronic SA4503 administration also significantly attenuated myocardial hypertrophy and restored ATP production in TAC mice. SA4503 administration also decreased hypertrophy-induced impairments in LV contractile function.

Conclusions

σ₁R stimulation with the specific agonist SA4503 ameliorates cardiac hypertrophy and dysfunction by restoring both mitochondrial Ca^2 + mobilization and ATP production via σ₁R stimulation.

General significance

Our observations suggest that σ₁R stimulation represents a new therapeutic strategy to rescue the heart from hypertrophic dysfunction.     

Soluble expression in Escherichia coli,purification and characterization of a human TF-1 cell apoptosis-related protein TFAR19

A novel human TF-1 cell apoptosis-related protein, TFAR19, cloned from a human leukemia cell line, TF-1, was first overexpressed in Escherichia coli with the sequence Met-Gly-His(6)-Gly-Thr-Asn-Gly, a hexahistidine sequence followed by a hydroxylamine cleavage site attached to its amino terminus. The resulting protein was soluble and single-step purified to homogeneity by metal chelating affinity chromatography. After cleavage of the purified His(6)-tagged TFAR19 sample with hydroxylamine, highly purified untagged TFAR19 protein was then obtained through an FPLC Resource Q column. The structural characteristics and function of the His(6)-tagged and untagged TFAR19 proteins were studied using circular dichroism, intrinsic fluorescence, and ANS-binding fluorescence spectra and apoptosis activity assay. The results show that alpha-helix is the main secondary structure of the proteins and the two forms of TFAR19 protein fold properly, which correspond well to their apoptosis activity expression. The results also indicate that the extra sequence including the His(6)-tag fused to the N-terminus of TFAR19 protein has a minimal effect on its structure and function, suggesting that the His(6)-tagged TFAR19 protein could be further used as an immobilized target for finding potential proteins which interact with TFAR19 from a cDNA library using in vitro ribosome display technique.     

深低温冻存组织工程化软骨在喉狭窄功能重建中的应用

目的:探讨低温保存组织工程化软骨在喉狭窄功能重建中的应用价值。方法:取3周龄新西兰兔关节软骨细胞,体外培养,取第2代对数生长期培养细胞,制成细胞悬液,调整软骨细胞悬液浓度约为5×107个/ml左右,接种于PGA三维支架材料上,复合物体外培养2周后冻存,冻存6个月后解冻复苏,再行体外培养观察,2周后接种于已建立的喉甲状软骨缺损模型的软骨缺损处,并设对照组。术后12周取材,行大体及组织学观察。结果:经低温冻存的组织工程化软骨生长良好,组织学观察有软骨形成,与周围软骨组织结合紧密,与非冻存组相比差异无统计学意义。结论:深低温冻存对组织工程化软骨的生物活性无明显的影响,低温冻存的组织工程化软骨可用于喉软骨缺损的修复,重建喉功能。     

骨转换生化指标的研究进展及选择依据

骨转化生化标志物的检测以其简便、快捷、无创等优点,在流行病学研究、长期跟踪监测、骨折风险评估等芳面独具优势.与骨影像学和骨形态计量学观察相比,其反映的是骨细胞活性的实时信息,因此是评价骨转换状况、观察药物早期疗效的重要手段.     

骨髓间充质干细胞在大鼠实验中的移植途径及比较

骨髓间充质干细胞是具有自我更新能力和分化潜能的一类成体干细胞,经过局部微环境的诱导,可在体内外进行扩展,到晚期可分化成为多种细胞系。当组织受损伤时,可迅速到达损伤部位,分化为特异的组织细胞,参与组织修复。骨髓间充质干细胞这种惊人的分化及组织修复能力,为治疗退行性疾病和器官损伤性疾病提供广阔前景,故成为科研热点。国内外相关实验研究多以大鼠为动物模型,而骨髓间充质干细胞如何进入大鼠体内并定植,是实验成功的重要前提。因此如何找到最合适、最安全的移植途径将骨髓间充质干细胞有效地移植进入大鼠疾病模型体内的受损区域,是研究者关心的重点。本文就目前骨髓间充质干细胞在大鼠实验中不同移植途径进行综述,并比较各种途径的优缺点,希望能对临床科研工作提供参考,并期待能有更成熟的移植手段来推动骨髓间充质干细胞实验研究的进展。     

同型半胱氨酸及甲状腺功能在他汀致冠心病患者肝功能异常中的研究

目的:研究同型半胱氨酸及甲状腺功能与他汀致冠心病患者肝功能异常的相关性。方法:服用阿托伐他汀钙(20mg,1次/日)后1-3个月肝功能正常组(ALT和AST均正常者)300例;肝功能轻度异常组(ALT或/和AST升高3倍以下者)300例;肝功能重度异常组(ALT或/和AST升高3倍以上者)300例。在转氨酶重度升高组中选取停用他汀药观察组和加用CoQ10(20mg,3次/日)治疗组各100例,对比两组转氨酶下降情况。结果:PCI术后服用他汀类药物治疗1-3个月后出现肝功能异常的冠心病患者,同型半胱氨酸水平升高,甲状腺功能降低;肝功能的异常与年龄及饮酒有相关性。转氨酶重度升高患者中,加用CoQ10治疗组较仅停药组转氨酶显著下降。结论:阿托伐他汀钙引起的冠心病患者同型半胱氨酸水平升高及甲状腺功能下降与肝功能损伤有明显相关性。CoQ10可显著降低转氨酶水平。