哌替啶对心室肌收缩的抑制作用及其机制

为明确哌替啶对心脏收缩的直接效应 ,并探讨其相关机制。采用Langendorff灌流心脏模型 ,观察了哌替啶对大鼠心室收缩功能的影响 ,并用荧光测钙技术和膜片钳技术探讨了哌替啶作用的钙离子机制。结果显示 ,哌替啶剂量依赖性地降低离体灌流心脏的LVDP×HR、 +dP/dt和 -dP/dt,而升高LVEDP。在酶解分离的心室肌细胞上 ,哌替啶剂量依赖性地降低细胞收缩时的钙瞬变幅度 ,并升高舒张末期的钙水平。哌替啶不影响高浓度咖啡因诱导的内钙释放。哌替啶使L 型钙电流强度降低到给药前的 67 4± 10 1% ,而不改变钙通道的激活和失活电位。哌替啶减弱钙电流的作用并不能被阿片受体阻断剂纳洛酮所阻断。以上结果表明 ,哌替啶能通过非阿片受体介导的途径阻断细胞外钙离子的内流 ,对心室收缩产生直接的抑制作用     

Bone marrow-derived stem cells contribute skin regeneration in skin and soft tissue expansion

Skin and soft tissue expansion stimulates the proliferation of skin epidermal basal cells and increase the dermal collagen deposition and angiogenesis. To explore the contribution of bone marrow‐derived stem cells (BMSCs) to the generation of “new” skin during the expansion, we used a chimeric mouse model in which the donor C57BL mice were engrafted with the bone marrow of enhanced green fluorescent protein (EGFP) transgenic mice. BMSCs were collected from the tibia and femur of EGFP⁺ transgenic mice, and then injected into normal C57BL mice via the tail vein (chimeric mice). Skin was obtained at different times (days 0, 7, 14, 21, 28, and 35). Skin stromal‐derived factor‐1 (SDF‐1) expression was evaluated. The number, distribution, and phenotype changes of EGFP⁺ cells in the skin were also evaluated by means of fluorescent microscopy. EGFP⁺ cells were present stably in the normal skin. The number of EGFP⁺ cells of the Group A mice changed with the tension, and reached the peak on day 21(17.1 ± 6.7%), as compared with either Group B (5.5 ± 1.0%) or Group C (5.1 ± 0.9%). The SDF‐1 expression in the expanded skin was significant increased (≈11‐fold, P < 0.01) compared to non‐expanded skin on day 21. Immunofluorescence showed EGFP⁺ cells were converted into vascular endothelial cells, epidermal cells, and spindle‐shaped dermal fibroblasts. Strain can promote the expression of SDF‐1 and facilitate the differentiation and proliferation of BMSCs in the expanded skin. J. Cell. Physiol. 226: 2834–2840, 2011. © 2011 Wiley‐Liss, Inc.     

一种定量检测人血清高敏C反应蛋白的化学发光免疫方法

旨在建立一种可定量检测人血清高敏CRP的化学发光检测方法 (High-sensitivity C-reactive protein quantifiable chemiluminescent immunoassay,hs-CRP CLIA)。首先利用亲和层析和离子交换层析技术从肝硬化病人腹水中纯化出高纯度的天然CRP作为免疫原制备了22株CRP单克隆抗体 (单抗),其中13株单抗在磷酸胆碱配体捕获ELISA中呈阳性,然后利用方正滴定法筛选出单抗10C5和10C11建立了hs-CRP CLIA。试剂盒评估结果显示：该方法对血清中干扰物质IgG、血红蛋白、甘油三酯等无非特异性反应;该方法检测灵敏度高,在0.04~20.38 mg/L范围内定量检测人血清CRP标准品呈良好线性关系 (R2＞0.993);该方法准确性高、可重复性好,平均回收率为99％,批内差为4.2％~5.8％,批间差为9.0％~11.5％;该方法与进口商品化高敏CRP ELISA试剂盒平行比较检测90份血清标本,结果显示两者有良好的可比性 (r=0.968)。综上,建立的hs-CRP CLIA是一种准确、可靠、可定量的高灵敏C反应蛋白检测方法,该方法的临床应用,有利于改善我国心脏病风险评估及肠炎性疾病预后判断。     

基于临界氮浓度的小麦地上部氮亏缺模型

基于3年的大田试验,选择代表性的中蛋白小麦品种（扬麦16）和低蛋白小麦品种（宁麦13）,分别构建了小麦地上部干物质临界氮浓度(N_cnc)稀释曲线模型、氮营养指数（NNI）模型和氮亏缺(N_and)模型.结果表明： 小麦地上部干物质临界氮浓度稀释曲线模型具有明确的生物学意义,小麦临界氮浓度与地上部最大干物质（DM）符合幂函数关系（扬麦16为N_cnc=4.65DM^-0.44;宁麦13为N_cnc=4.33DM^-0.45）;小麦地上部氮营养指数模型可以准确诊断氮素营养状况;小麦地上部氮亏缺模型可以定量调控氮肥管理措施.利用2007-2008年的独立试验资料对小麦地上部干物质临界氮浓度稀释模型、氮营养指数模型和氮亏缺模型进行检验和测试,结果表明模型的准确性较高,普适性较强.本文所构建模型可以直接用于诊断调控小麦氮素营养,为小麦生产中精确施肥管理提供了较好的技术途径和理论基础.     

发酵麸皮多糖酶辅助提取工艺优化及其生物活性研究

通过响应面法优化提取发酵麸皮多糖的工艺,并评价其体外益生和抗氧化活性。以发酵麸皮多糖的得率为响应值,采用纤维素酶酶解与水浴浸提相结合的方法提取发酵麸皮多糖,以纤维素酶添加量、料液比、水浴浸提温度、水浴浸提时间为试验因素建立数学模型,筛选最佳提取工艺条件。通过测定还原力、DPPH和·OH自由基的清除能力对比发酵和未发酵麸皮多糖的体外抗氧化活性,并通过测定嗜酸乳杆菌、植物乳杆菌、两歧双歧杆菌的生长对比发酵和未发酵麸皮多糖的体外益生活性。结果表明,发酵麸皮多糖最佳提取工艺为:料液比1∶16(w/v),酶添加量1 000 U/g,水浴浸提温度90℃,水浴浸提时间60 min,在此条件下发酵麸皮多糖的得率实测值为73. 35%。发酵麸皮多糖具有较强的DPPH和·OH自由基的清除能力,可促进嗜酸乳杆菌、植物乳杆菌和两歧双歧杆菌的生长。     

鸡传染性法氏囊病毒实时qRT-PCR检测方法的建立及初步应用

根据高效培养鸡传染性法氏囊病毒（IBDV）时对病毒滴度检测的需要,本文针对BDV的VP4基因的保守序列设计并合成了一对引物,以所构建的重组质粒作为阳性标准品,建立了检测IBDV核酸载量的SYBR Green I荧光定量实时RT-PCR(qRT-PCR)方法,结果表明,其Ct值与标准品模板在4.03×1E1～1E9 拷贝/μL范围内呈良好的线性关系,对IBDV核酸的最低检出量为40拷贝/μL,灵敏度是常规RT-PCR检测方法的1000倍;该方法不与其它禽源病毒发生交叉反应,批内变异系数小于0.05%。应用本方法对DF-1细胞中IBDV的增殖滴度进行了测定,并与经典的TCID50测定方法进行了比较。结果显示两种方法测定的IBDV在微载体悬浮培养和方瓶静态培养条件下DF-1细胞上的增殖曲线都具有一定的平行关系,且qRT-PCR方法比TCID50方法更加快速和敏感,更适合于对IBDV增殖滴度的实时快速测定。     

表面活性剂对土壤中多环芳烃生物有效性影响的研究进展

表面活性剂能够改变多环节烃(Polycyclic aromatic hydrocarbons,PAHs）在土壤中的溶解度、吸附/解吸平衡和与土壤微生物的相互作用,从而改变PAHs的生物有效性,表面活性剂主要通过降低土壤-水之间的界面张力,增加PAHs的溶解度、促进PAHs的运输等方式来加强PAHs的生物有效性,但由于表面活性剂本身对微生物的毒害作用或无毒的表面活性剂优先作为微生物的生长基质,可能会对PAHs的生物有效性起到抑制作用,另外,表面活性剂对土壤中不同形态的PAHs生物有效性的影响不同,表面活性剂、PAHs和土壤微生物的类型浓度以及土壤的物理化学条件等都对PAHs的生物有效性有影响。     

The polysaccharides from Ganoderma lucidum: Are they always inhibitors on human hepatocarcinoma cells?

The antitumor activity of intracellular polysaccharides from submerged fermentation of Ganoderma lucidum was investigated focusing on the inhibition on human liver cancer cells. The polysaccharides inhibited human hepatocarcinoma cell HepG2 during earlier phase with lower dosage but obviously became less functional in later phase regardless of the dosage applied. However, apoptosis of the drugged HepG2 cells appeared in later incubation phase with high dosage, and the apoptosis could be enhanced by supplemental dose of the intracellular polysaccharides. Nevertheless, the intracellular polysaccharides inhibited other human hepatocarcinoma cells such as BEL-7402 and Huh-7 but luckily stimulated human normal liver cell L02 only in a positive dose- and time-dependent manner; so did the sulfated extracellular polysaccharides when it inhibited HepG2 and L02 cells. However, the toxicity of sulfated extracellular polysaccharides to L02 cells can be eliminated by the intracellular polysaccharides.     

Biochemical characterization of indole prenyltransferases: filling the last gap of prenylation positions by a 5-dimethylallyltryptophan synthase from Aspergillus clavatus

The putative prenyltransferase gene ACLA_031240 belonging to the dimethylallyltryptophan synthase superfamily was identified in the genome sequence of Aspergillus clavatus and overexpressed in Escherichia coli. The soluble His-tagged protein EAW08391 was purified to near homogeneity and used for biochemical investigation with diverse aromatic substrates in the presence of different prenyl diphosphates. It has shown that in the presence of dimethylallyl diphosphate (DMAPP), the recombinant enzyme accepted very well simple indole derivatives with L-tryptophan as the best substrate. Product formation was also observed for tryptophan-containing cyclic dipeptides but with much lower conversion yields. In contrast, no product formation was detected in the reaction mixtures of L-tryptophan with geranyl or farnesyl diphosphate. Structure elucidation of the enzyme products by NMR and MS analyses proved unequivocally the highly regiospecific regular prenylation at C-5 of the indole nucleus of the simple indole derivatives. EAW08391 was therefore termed 5-dimethylallyltryptophan synthase, and it filled the last gap in the toolbox of indole prenyltransferases regarding their prenylation positions. K(m) values of 5-dimethylallyltryptophan synthase were determined for L-tryptophan and DMAPP at 34 and 76 μM, respectively. Average turnover number (k(cat)) at 1.1 s(-1) was calculated from kinetic data of L-tryptophan and DMAPP. Catalytic efficiencies of 5-dimethylallyltryptophan synthase for L-tryptophan at 25,588 s(-1)·M(-1) and for other 11 simple indole derivatives up to 1538 s(-1)·M(-1) provided evidence for its potential usage as a catalyst for chemoenzymatic synthesis.