针对性rDNA-ITS序列分析不支持冬虫夏草复合种假设

冬虫夏草是有名的中药材,作为滋补药物已有数百年历史。它主要分布于亚洲高纬度草甸地带,寄主为蝙蝠蛾幼虫。目前有许多证据尤其是在rDNA-ITS水平上支持中国被毛孢Hirsutella sinensis是冬虫夏草的唯一无性型。然而,除了那些属于明显的错误注册的序列以外,从NCBI数据库检索得到的多个已注册为"冬虫夏草"的序列彼此之间的差异十分显著。基于这些有差异的GenBank序列,有些作者提出了冬虫夏草种复合群体及其包含的三个隐存种的假设。为检验该假设,我们以单株冬虫夏草子实体为材料,开展了rDNA-ITS序列分析研究。冬虫夏草样品分别采自中国的四川和青海两省。结果显示只有‘冬虫夏草A组’应为真正的冬虫夏草,而B组和C组很有可能属于其他真菌,而非冬虫夏草的隐存种。     

丁酸钠至少部分通过NF-Y 依赖的TXNIP 表达诱导人肺癌细胞A549死亡

组蛋白去乙酰化酶（HDACs）抑制剂丁酸钠调节细胞分化、增殖和抑制肿瘤发生。硫氧还蛋白相互作用蛋白( thioredoxin-interacting protein,TXNIP)通过负性调控硫氧还蛋白的活性,调控细胞内的氧化还原平衡,抑制细胞生长。本研究证明,丁酸钠可通过激活依赖于转录因子NF-Y的TXNIP 表达,诱导人非小细胞肺癌细胞A549死亡。MTT法显示,5 mmol/L丁酸钠处理A549 细胞72 h可显著诱导其死亡;流式细胞分析发现,其中大部分细胞以凋亡形式死亡。表达芯片分析表明,在丁酸钠处理的A549 细胞中,TXNIP 的mRNA 水平显著提高30～50倍;实时定量PCR、免疫细胞化学和蛋白质印迹结果进一步证明,丁酸钠可显著上调TXNIP 表达。荧光素酶报告基因分析证明,与对照细胞比较,丁酸钠刺激的细胞内报告酶活性可提高约10 倍,提示丁酸钠可激活TXNIP 启动子的转录活性。TXNIP 启动子删除突变分析显示,删除NF-Y 结合的DNA 序列显著降低丁酸钠对TXNIP 启动子的激活能力, 表明NF-Y转录因子参与丁酸钠介导的TXNIP基因转录激活。为分析TXNIP 在A549 细胞中的定位和部分功能,在A549细胞 中过表达GFP TXNIP 融合蛋白及其截短突变体融合蛋白;结果显示,野生型和保留N 端1-281aa的截短突变体定位在细胞核,而删除N 端1-200aa 时,其定位在细胞核和细胞质,提示N 端1 200aa 可调节该蛋白质的定位。然而,丁酸钠刺激未发现表达的GFP TXNIP在细胞内定位改变。以上结果表明,丁酸钠可通过激活转录因子NF YC 依赖的TXNIP激活,诱导A549 细胞死亡,但不能改变TXNIP蛋白在细胞内的定位。上述结果还提示,TXNIP 的N 端1-200aa 可能在调节TXNIP 的细胞定位中发挥作用。是否丁酸钠刺激TXNIP表达导致的细胞死亡系通过改变细胞氧化压力,以及TXNIP在细胞中定位的详尽调节机制尚待进一步研究证明。     

Anti-inflammatory and Anti-apoptotic Effect of Combined Treatment with Methylprednisolone and Amniotic Membrane Mesenchymal Stem Cells After Spinal Cord Injury in Rats

This study was undertaken to investigate the synergistic effects of methylprednisolone (MP) administration and transplantation of amniotic membrane mesenchymal stem cells (AM-MSCs) following T11 spinal cord clip compressive injury in rats. The combination treatment with MP (50 mg/kg) and delayed transplantation of AM-MSCs after rat spinal cord injury, significantly reduced (1) myeloperoxidase activity, (2) the proinflammatory cytokines: tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-17, interferon-γ and (3) the cell apoptosis [terminal deoxynucleotidyl transferase, dUTP nick end labeling (TUNEL) staining, and caspase-3, Bax and Bcl-2 expressions]; increased: (1) the levels of the anti-inflammatory cytokines (IL-10 and transforming growth factor-β1) and (2) the survival rate of AM-MSCs in the injury site. The combination therapy significantly ameliorated the recovery of limb function (evaluated by Basso, Beattie and Bresnahan score). Taken together, our results demonstrate that MP in combination with AM-MSCs transplantation is a potential strategy for reducing secondary damage and promoting functional recovery following spinal cord injury.     

miR482介导的植物生物胁迫响应

植物在生长发育过程中会遇到各种生物胁迫,根据响应过程的不同,可将之分为基于蛋白质的生物胁迫和基于RNA的生物胁迫。miR482是一种植物特有的、已在23个物种中被证实存在的小RNA。miR482参与指导植物次级phasiRNA的合成,其主要靶标为植物庞大的Ⅳ=日§三R尺类家族抗病基因。本文通过整理近年来ETI（effector-triggeredimmunity）相关的NBS-LRR类抗病基因和抗RNA沉默抑制相关miR482级联调控的研究成果,总结出了miR482介导植物两类生物胁迫响应的调控机制。     

Cerebral Hemorrhage Increases Plasma Concentrations of Noradrenalin and Creatine Kinase MB Fraction with Induction of Cardiomyocyte Damage in Rats

The incidence of cardiac damage is high during acute cerebral hemorrhage. The animal data on the relationship between cerebral apoplexy and cardiac damage are lacking. Thus, the aim of the study was to evaluate the effects of cerebral hemorrhage on plasma concentrations of monoamine transmitter noradrenalin (NA), creatine kinase muscle and brain (CK-MB) isoenzyme fraction, and cardiomyocyte changes in the rat model. In this study, 140 Wistar rats were randomly and equally divided into experimental and control groups, and collagenase was injected into the right caudate nucleus to induce cerebral hemorrhage in the experimental group. Plasma NA was analyzed using high-performance liquid chromatography with electrochemical detection and serum CK-MB was measured by enzyme reaction rate method. We found that both NA and CK-MB were elevated (p < 0.05) at 6 h after cerebral hematoma formation; the levels were 2.46 ± 0.05 μg/L and 3.51 ± 0.23 μkat/L, respectively. NA and CK-MB concentrations reached peak levels at 24 h which were found to be 3.52 ± 0.06 μg/L and 5.47 ± 0.49 μkat/L, respectively. Thereafter, NA and CK-MB concentrations decreased gradually. Plasma NA declined to the preoperative level (1.66 ± 0.03 μg/L) at 72 h, while CK-MB level (2.71 ± 0.17 μkat/L) was found to be still higher than its preoperative level. It was, therefore, concluded that plasma NA might be involved in the induction and development of cardiomyocytes damage during cerebral hemorrhage.     

美洲大蠊中枢DUM神经元的分离和电压门控Na+电流的记录

【目的】建立美洲大蠊Periplaneta americana中枢神经系统背侧不成对中间神经元（dorsal unpaired median neurons, DUM neurons）的分离方法和DUM神经元电生理实验模型。【方法】IA型胶原酶法消化美洲大蠊末端腹神经节, 机械吹打得到DUM神经元细胞, 运用膜片钳技术记录DUM神经元细胞电压门控Na+电流。【结果】分离得到的DUM神经元细胞状态良好, 具有DUN神经元典型的梨状形态和表面特征。以膜片钳全细胞方式记录到的Na+电流符合钠通道电流特征。【结论】IA型胶原酶消化得到美洲大蠊DUM神经元细胞的方法可靠, 能稳定地记录到Na+电流。本文描述的方法为昆虫神经细胞的电生理机制研究提供一个可用的实验模型。     

杂交狗牙根不同品种(系)叶片解剖结构及耐磨性研究

以7个杂交狗牙根品种(系)的叶片进行解剖研究,结果表明,各品种(系)均具禾本科C₄植物叶片典型结构,其独特处是:中脉结构与平行脉相似;中脉维管束、平行脉大维管束的维管束鞘内侧韧皮部外有一层纤维细胞;泡状细胞外壁很少角化。综合比较7个品种(系)叶片的角质层厚度、机械组织含量、维管束排列密度,得出叶片耐磨性综合指数,可作为耐践踏性的指标之一。此指数最高的品种是"TifSport"。