鲤鱼卵黄发生期血钙水平调节初步研究

在雌鲤卵黄发生期的10月～次年1月和斯坦氏小体(CS)发育静止期进行升高细胞外钙浓度实验,分别用OCPC法测定血浆钙水平的变化,超微结构观察CS的组织学变化.结果表明,鲤鱼血钙水平在卵黄发生期存在一定性别差异,雄鲤水平普遍低于雌鲤,在11月达显著性水平.升高细胞外钙浓度的各处理组中CS的超微结构发生了不同程度的变化,均表现为细胞代谢活动增强.     

不同含湿率及加载条件对人皮质骨纳米压痕测试的影响

目的:探讨不同含湿率及加载条件对人皮质骨纳米压痕测试的影响。方法:采用美国Hysitron纳米压痕仪,设定不同加载模式(高峰载荷分别为300、400、500 nm;加载速度分别为6、8、10 nm/s)对不同含湿率(20‰、30‰、40‰、50‰、60‰)人皮质骨进行弹性模量及硬度测量。结果:在同一加载模式下,不同含湿率标本的测试值随着含湿率增高,弹性模量及硬度值均显著降低(P0.01);三种不同加载模式对含湿率为20‰标本测试值无明显变化;对含湿率60‰标本测试值有显著性影响(P0.02)。结论:纳米压痕仪测试骨微观力学特性时,测试值不仅受标本本身含湿率的影响,当测试条件改变,对湿润标本测试结果也完全不同。当使用纳米压痕技术时,通常采用脱水包埋处理的标本测试出的机械性能,对我们在微观层面认识人体骨在湿润的生理环境下的机械性能是不够全面的。     

Climatic signals in tree ring of Picea schrenkiana along an altitudinal gradient in the central Tianshan Mountains, northwestern China

Tree-ring samples of Picea schrenkiana (Fisch. et Mey) were studied along an altitudinal gradient in the central Tianshan Mountains, and ring-width chronologies were developed for three sites at different altitudes: low-forest border (1600–1700 m a.s.l.), interior forest (2100–2200 m a.s.l.), and upper treeline (2600–2700 m a.s.l.). Annual ring-width variations were similar among the three sites but variability was greatest at the low-forest border site. The statistical characters of the chronologies showed that mean sensitivity (MS) and standard deviation (SD) decreased with increasing elevation. In other words, the response of tree growth to environmental changes decreased with increasing altitude. To understand the differing response of trees at different elevations to the environmental changes, response function analysis was used to study the relationships between tree-ring widths and mean monthly temperature and total monthly precipitation from 1961 to 2000. The results showed that precipitation was the most important factor limiting tree radial growth in the arid central Tianshan Mountains, precipitation in August of the prior growth year played an important role on tree's radial growth across the entire altitudinal gradient even at the cold, high-elevation treeline site. It is expected that with increasing altitude air temperature decreased and precipitation increased, the importance of precipitation on tree growth decreased, and the response of tree growth to environmental changes decreased, too. This conclusion may be helpful to understand and research the relationship between climatic change and tree growth in arid and semiarid area.     

艾蒿精油对家蝇的忌避及熏蒸活性

应用“Y”型嗅觉仪对家蝇进行了生物测定。结果表明,艾蒿(Artemisia vulgars L．)精油20μL和25μL剂量对家蝇Musca domestica rieina有很强的忌避活性,平均忌避活力分别为86％和88％,显著高于5和10μL剂量。植物精油对家蝇成虫具有很好的熏蒸活性。随着精油浓度的升高和熏蒸时间的延长,试虫的死亡率显著增加。艾蒿精油浓度为20μL／mL时,家蝇成虫的死亡率在24h后即达到100％;对照在24,48,72和96h时家蝇成虫的死亡率分别为0,0,5％和11％。     

逆转录病毒载体介导胸苷磷酸化酶在胰腺癌细胞表达

人胸腺嘧啶核苷磷酸化酶（ＴＰ）在一些肿瘤组织中活性增高,但其功能目前了解尚少。构建了表达ＴＰ的重组逆转录病毒载体,直接导入人胰腺癌ＰＣ－２细胞,ｍＰＣＲ扩增、Ｓｏｕｔｈｅｒｎ及Ｎｏｒｔｈｅｒｎ印迹和原位杂交证实转染细胞有外源ＴＰ的整合及表达,酶活性检测发现含外源ＴＰ细胞ＴＰ活性比ＰＣ－２细胞的内源性ＴＰ活性高ＴＰ活性高４０－７０倍,生长曲线和＾３Ｈ－ＴｄＲ参入率检测未发现含外源ＴＰ细胞生物学行为的     

小麦胚芽蛋白的研究进展

小麦胚芽是面粉加工过程中的副产物,小麦胚芽蛋白具有良好的氮溶解度、起泡性、乳化性以及保水性、氨基酸比例平衡,不仅是饮料、食品以及医疗产品良好的添加剂,而且具有较强的产品开发潜力。对小麦胚芽蛋白的组成成分、理化性质、提取以及麦胚蛋白产品开发利用这四个方面进行简要的介绍,旨在为小麦胚芽蛋白的全面开发利用提供依据。     

Reticulon 3 interacts with NS4B of the hepatitis C virus and negatively regulates viral replication by disrupting NS4B self‐interaction

The non‐structural protein 4B (NS4B) of the hepatitis C virus (HCV) is an endoplasmic reticulum (ER) membrane protein comprising two consecutive amphipathic α‐helical domains (AH1 and AH2). Its self‐oligomerization via the AH2 domain is required for the formation of the membranous web that is necessary for viral replication. Previously, we reported that the host‐encoded ER‐associated reticulon 3 (RTN3) protein is involved in the formation of the replication‐associated membranes of (+)RNA enteroviruses during viral replication. In this study, we demonstrated that the second transmembrane region of RTN3 competed for, and bound to, the AH2 domain of NS4B, thus abolishing NS4B self‐interaction and leading to the downregulation of viral replication. This interaction was mediated by two crucial residues, lysine 52 and tyrosine 63, of AH2, and was regulated by the AH1 domain. The silencing of RTN3 in Huh7 and AVA5 cells harbouring an HCV replicon enhanced the replication of HCV, which was counteracted by the overexpression of recombinant RTN3. The synthesis of viral RNA was also increased in siRNA‐transfected human primary hepatocytes infected with HCV derived from cell culture. Our results demonstrated that RTN3 acted as a restriction factor to limit the replication of HCV.     

腐食酪螨在不同温度和营养条件下生长发育的比较研究

在12.5℃、15℃、20℃、25℃和30℃恒温下,用啤酒酵母粉和玉米粉为饲料,测定了不同温度和饲料条件下腐食酪螨Tyrophagus putrescentiae各个发育阶段和世代的发育历期,获得其在各条件下的发育起点温度和有效积温。结果表明,在本文的实验温度范围内,该螨的发育历期与温度呈负相关,即随着温度的升高发育历期缩短。在各发育阶段不同饲料条件下发育起点温度和有效积温都有所差异。用啤酒酵母粉作饲料时,腐食酪螨的全世代历期为48.04天（12.5℃下）和8.41天（30℃下）,发育起点温度为10.18℃,有效积温为155.44 d·℃; 用玉米粉作饲料时,全世代历期为78.79天（12.5℃下）和10.77天（30℃下）,发育起点温度为10.52℃,有效积温为208.33 d·℃。以成螨体长和体宽为指标,比较了在各温度条件及不同饲料条件对其生长的影响,结果表明不同饲料对螨体大小有显著影响,温度的影响不明显。     

Anthraquinone G503 Induces Apoptosis in Gastric Cancer Cells through the Mitochondrial Pathway

G503 is an anthraquinone compound isolated from the secondary metabolites of a mangrove endophytic fungus from the South China Sea. The present study elucidates the anti-tumor activity and the underlying mechanism of G503. Cell viability assay performed in nine cancer cell lines and two normal cell lines demonstrated that the gastric cancer cell line SGC7901 is the most G503-sensitive cancer cells. G503 induced SGC7901 cell death via apoptosis. G503 exposure activated caspases-3, -8 and -9. Pretreatment with the pan-caspase inhibitor Z-VAD-FMK and caspase-9 inhibitor Z-LEHD-FMK, but not caspase-8 inbibitor Z-IETD-FMK, attenuated the effect of G503. These results suggested that the intrinsic mitochondrial apoptosis pathway, rather than the extrinsic pathway, was involved in G503-induced apoptosis. Furthermore, G503 increased the ratio of Bax to Bcl-2 in the mitochondria and decreased the ratio in the cytosol. G503 treatment resulted in mitochondrial depolarization, cytochrome c release and the subsequent cleavage of caspase -9 and -3. Moreover, it is reported that the endoplasmic reticulum apoptosis pathway may also be activated by G503 by inducing capase-4 cleavage. In consideration of the lower 50% inhibitory concentration for gastric cancer cells, G503 may serve as a promising candidate for gastric cancer chemotherapy.