脂氧素A_4对大鼠急性肝衰竭的保护作用

目的观察脂氧素A4(LXA4)对大鼠急性肝衰竭的保护作用并初步探讨其机制。方法采用D-氨基半乳糖(D-GalN)+脂多糖(LPS)建立大鼠急性肝衰竭动物模型。30只大鼠随机分为四组:正常组、模型组、脂氧素组、四氢化吡咯二硫代氨基甲酸酯(PDTC)组。肝组织病理切片观察肝组织损伤情况;自动生化仪检测肝功能;ELISA法检测血清TNF-α及IL-6水平;免疫组化法检测肝组织核因子κB(NF-κB)表达。结果大鼠急性肝衰竭时,肝组织炎症坏死明显,肝脏转氨酶明显升高,血清IL-6及TNF-α水平显著升高,肝组织NF-κB表达明显增强;脂氧素组及PDTC组组织学改变均明显好转,肝脏转氨酶、细胞因子及NF-κB表达明显下降(与模型组比较,P0.01,);脂氧素组及PDTC组比较,上述指标之间P0.01。结论 LXA4对大鼠急性肝衰竭有明显的保护作用,这种保护作用部分是通过阻断肝组织NF-κB活化,减少促炎细胞因子的释放来实现的。     

抗逆相关基因GmAREB转基因小麦的获得与鉴定

从大豆中克隆一个抗逆相关的bZIP类转录因子基因GmAREB,功能分析表明:GmAREB基因的过表达可以显著提高转基因拟南芥和烟草的抗旱、耐盐和耐寒性。为了获得抗逆转基因小麦,本研究利用玉米的Ubiqutin启动子控制GmAREB基因表达,构建了用于小麦转化的载体pSK-GmAREB。采用基因枪共转化法转化小麦品种郑147和济麦22。通过PCR检测共获得T0代的阳性植株70株,转化率为1.37%。其中,郑147阳性植株共31株,转化率为2.14%;济麦22阳性植株39株,转化率为1.08%。目前,已经获得T1代转基因株系18个,其中以郑147为受体的株系4个,以济麦22为受体的株系14个。对部分株系进行Southern blotting分析,进一步证实GmAREB基因已经整合到小麦基因组中。在低温胁迫条件下,3个以济麦22为受体的转基因株系体内脯氨酸的积累与受体小麦相比有显著增加,初步证明在小麦中过表达GmAREB基因,可以促进渗透调节物质脯氨酸的积累,可能有助于转基因小麦抗逆性的提高。本研究为进一步筛选抗逆转基因小麦新材料奠定了基础。     

籼稻232蜡质基因转录起始位点的鉴定

Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交分析和蜡质基因ｃＤＮＡ的序列分析表明水稻蜡质基因的转录本可能延伸到翻译起始密码子（ＡＴＧ）上游１２ｋｂ处。据此设计了２１Ｎｔ的寡核苷酸引物,并以籼稻２３２胚乳ＲＮＡ为模板,以引物延伸法确定籼稻２３２蜡质基因的转录起始点,籼稻蜡质基因的转录起始旁邻顺序ＣＴＣＡＣＣＡ与高等植物基因的转录起始点一致顺序ＣＴＣＡＴＣＡ仅相差１个碱基。通过顺序比较,对东乡野生稻蜡质基因中的转录起始位点的位置,以及对此两稻种中ＴＡＴＡ盒的可能顺序进行了讨论。     

Bovine cumulus cell expansion does not depend on the presence of an oocyte secreted factor

Communication between the oocyte and its somatic cells has been shown to be important in oocyte development. Here we examined how the oocyte may be involved in bovine cumulus cell expansion. Intact bovine cumulus oocyte complexes (COC) were obtained by puncturing antral follicles. From the intact COC, oocytectomised complexes (OOX) were produced by micro surgical removal of the oocyte. Clumps of cumulus cells (CC) were obtained by micro-dissection. Intact or OOX complexes or CC were matured in the presence of fetal calf serum and hFSH (6 mlU/ml) for 24 hr and the degree of expansion measured. The presence of the oocyte is not essential to allow bovine cumulus expansion to occur as expansion occurred in all groups. Murine OOX complexes from eCG primed 35–40-day-old C57BL6/CBA F₁ hybrids (known to require the presence of an oocyte secreted factor for cumulus expansion) were cultured with or without denuded bovine oocytes (1 oocyte/μl). Murine OOX complexes expanded only in the presence of denuded bovine oocytes. Thus some factor produced by bovine oocytes enabled expansion of murine OOX complexes. To determine whether the factor is secreted by bovine oocytes, murine OOX were cultured with or without media conditioned by bovine oocytes (1 oocyte/μl for 4 hr). Significant expansion of murine OOX occurred in media conditioned by bovine oocytes. This shows that the cumulus expansion enabling effect of bovine oocytes is released into the surrounding media. Media conditioned by bovine oocytes and then frozen for up to 1 month showed that the activity by the factor can withstand freezing. © 1995 wiley-Liss, Inc.     

蚤数量与宿主数量和气象因子的关系

根据内蒙古自治区鄂托克旗和鄂托克前旗1975一1989年长爪沙鼠密度、蚤指数监测数据和本地区气象站的,项气象因子资料,分别求出了蚤指数与鼠密度的直线和曲线的回归模型,与气象因子的最优回因子集模型和标准回归模型,给出了鼠蚤因子和气象因子间的典型棺关分析。结论：宿主数量变化导致蚤指数变化;气象因子综合影响蚤指数;相对湿度和地表温度是影响蚤数量变动的重要因子;气象因于对蚤指数的影响大于对鼠密度的影响。     

肺癌的表皮生长因子受体分子靶向治疗与基因突变

肺癌分子靶向治疗近年来取得较大进展,特别是针对表皮生长因子受体（EGFR）分子靶向药物表现出确定的临床效果。临床应用表明,EGFR基因酪氨酸激酶域体细胞突变与非小细胞肺癌患者对酪氨酸激酶抑制剂吉非替尼的敏感性相关,本文就相关的研究进行了简述。     

植物的次生生长及其分子调控

植物的次生生长是一重要的生命活动, 特别是植物次生木质部的形成对人类生产和生活具有重大意义。次生生长包括维管组织形成、次生细胞壁形成、木质化、PCD以及心材形成等过程。生长素和多个转录因子家族如MYB、NAC、AP2/EREBP、homeobox、MADS等参与了这一过程的调控, 利用分子生物学手段特别是基因组学方法, 人们已分离到生长素信号途径基因以及转录因子家族中的相关调控基因。文章介绍了植物次生生长的活动过程, 并论述了次生生长过程中调控基因的研究情况。     

Early-stage litter decomposition and its influencing factors in the wetland of the Sanjiang Plain, China

Using the litter bag technique, the decomposition rates and their influencing factors were studied by investigating three wetland macrophytes, Calamagrostics angustifolia, Carex meyeriana and Carex lasiocapa, in Sanjiang Plain, Northeast China. It was revealed that C. lasiocapa lost 28.91% of its weight, C. angustifolia lost 31.98% and C. meyeriana lost 32.99% after 164 days. Another finding was that the amount of organic carbon in the litter of C. angustifolia and C. lasiocapa fluctuated, but continuously decreased in that of C. meyeriana. However, all the three types of litter released organic carbon. Nitrogen was released substantially from the litter of both C. angustifolia and C. meyeriana, but accumulated in the litter of C. lasiocapa. Phosphorus concentrations in all the three types of litter apparently decreased first and then slightly increased. Overall, P release was observed in all the three types of litter. The C/N and C/P ratios varied significantly in the decomposition process. The decomposition rates and nutrient content variations were simultaneously influenced by the quality of the litter as well as the environmental factors in the Sanjian Plain, but they were more strongly affected by the quality of the litter.