基质金属蛋白酶MMP-26能有效促进人绒毛膜上皮癌细胞JEG-3浸润能力

胚胎植入过程中,滋养层细胞浸润与肿瘤的迁移过程非常相似,但显著的区别在于前者是受严格调控的有节制的浸润,基质金属蛋白酶(MMPs)的许多成员在其中起重要的作用.MMP-26是近年来发现的MMPs家族的新成员,它在滋养层细胞中的作用所知甚少.利用国际常用的人滋养层细胞模型——人绒毛膜上皮癌细胞系(JEG-3)作为体外实验模型,探讨MMP-26在人滋养层细胞浸润调节中的作用.将含有MMP-26全长cDNA的pCR3.1质粒转染到JEG-3细胞中,获得过量表达MMP-26基因的稳定细胞系JEG-3/MMP-26;细胞浸润分析表明JEG/MMP-26细胞的浸润能力较母本细胞明显增强;RT-PCR和明胶酶谱分析显示JEG-3/MMP-26细胞中MMP-9的表达和分泌水平提高;双荧光免疫细胞化学进一步显示MMP-26和MMP-9蛋白在细胞中有共定位现象.上述结果表明MMP-26能有效促进人滋养层细胞浸润,其作用可能是通过与其他MMP分子(如MMP-9)的协调来实现的.     

家蚕血液过氧化氢酶活力及其与蚕体抗逆性的关系

家蚕召Bombyx mori(L.)血液过氧化氢酶(CAT)活力随发育时期呈现有规律的动态变化。在幼虫期,CAT活力以龄初、龄末较高,而龄中较低;化蛹后,CAT活力迅速上升,至中期达到峰值,随后迅速下降直至羽化。不同性别间CAT活力均以雄性较高;不同蚕品种间CAT活力有很大差异;饲料对CAT活力有一定影响,人工饲料育蚕CAT活力略大于桑叶育的;高温冲击和氟化物添食都能引起CAT活力的显著变化,但变化的幅度因品种、性别、时期和添食剂量而有所不同。研究认为,家蚕血液CAT活力与其发育变态、体内代谢均具有密切关系,逆境条件下CAT活力变化幅度的大小可以作为家蚕抗逆性强弱的一个重要生理指标。     

HDAC6 inhibitor WT161 performs anti-tumor effect on osteosarcoma and synergistically interacts with 5-FU

Background: WT161, as a selective HDAC6 inhibitor, has been shown to play anti-tumor effects on several kinds of cancers. The aim of the present study is to explore the roles of WT161 in osteosarcoma and its underlying mechanisms.Methods: The anti-proliferative effect of WT161 on osteosarcoma cells was examined using MTT assay and colony formation assay. Cell apoptosis was analyzed using flow cytometer. The synergistic effect was evaluated by isobologram analysis using CompuSyn software. The osteosarcoma xenograft models were established to evaluate the anti-proliferative effect of WT161 in vivo.Results: WT161 suppressed the cell growth and induced apoptosis of osteosarcoma cells in a dose- and time-dependent manner. Mechanistically, we found that WT161 treatment obviously increased the protein level of PTEN and decreased the phosphorylation level of protein kinase-B (AKT). More importantly, WT161 showed synergistic inhibition with 5-FU on osteosarcoma cells in vitro and in vivo.Conclusions: These results indicate that WT161 inhibits the growth of osteosarcoma through PTEN and has a synergistic efficiency with 5-FU.     

利用叶绿素荧光评估草原植物羊草缺磷缺氮状况

羊草(Leymus chinensis)是北方草原的重要牧草。准确评估其营养状况,对维护羊草草原的生产力具有重要意义。以羊草幼苗为材料,利用能同时表征2个光系统光化学活性的叶绿素荧光检测技术,对缺氮和缺磷处理下的叶片光化学活性进行分析。结果表明,缺氮处理20天后羊草叶片叶绿素含量降低近50%。同期缺磷及缺氮处理对PSⅡ功能的影响总体大于PSⅠ。与对照相比,缺氮叶片的Φ(Ⅱ)和Φ(Ⅰ)分别比对照降低了30.3%与38.5%;ETR(Ⅱ)与ETR(Ⅰ)分别降低30.8%和28.9%。缺磷处理组Φ(Ⅱ)和ETR(Ⅱ)的降低幅度约为缺氮的1/2。这些定量研究结果对及时有效地诊断和区分羊草植物氮磷缺乏状况具有重要的参考价值。     

湘西河流表层沉积物重金属污染特征及其潜在生态毒性风险

花垣河和峒河是湘西地区受到锰矿和铅锌矿生产影响严重的两条河流。通过表层沉积物采样分析了Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量,根据BCR连续提取程序分析沉积物样品中重金属的地球化学赋存形态,采用内梅罗指数法和地积累指数法评价了沉积物重金属污染特征,根据重金属的富集程度探讨了重金属污染来源,采用淡水生态系统沉积物质量基准(SQGs,TEL/PEL)和毒性单位评价了花垣河和峒河沉积物中重金属元素的生态毒性风险。结果表明,花垣河和峒河绝大多数位点的表层沉积物中Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量高于参照点,形成严重的复合污染,花垣河沉积物中重金属的污染水平明显高于峒河,但沿程变化规律不明显,而峒河沉积物中重金属的沿程变化较有规律,即上游含量低,中下游含量较高。两条河流表层沉积物中富集程度居前列的均为Cd、Pb、Zn和Mn。花垣河和峒河沉积物重金属污染主要来源于矿业生产所产生废渣和废水的点排放。在花垣河和峒河的大多数位点,Cd、Pb和Mn的形态具有共同特征,其生物可利用态均较大程度地超过生物不可利用态,而且Mn和Cd的生物可直接利用态所占比例远高于其它重金属,而Cu和Cr的生物可直接利用态所占比例很低。花垣河沉积物中Cd、Pb和Zn在所有位点极大地超过PEL,在峒河中下游,Cd、Pb、Ni和Zn超过PEL,具有较大的潜在生物毒性。除上游S1位点外,花垣河的其余各位点都具有明显的急性毒性,峒河中下游各位点具有明显的急性毒性,这些河段需要重点治理。     

白粉菌属一新种——南非金钟花白粉菌

寄生于南非金钟花（PhygeliuscapensisE.May）上的白粉菌属新种:南非金钟花白粉菌ErysiphephygeliiWangetZhangsp.nov.。模式标本分别保存于云南农业大学植病所真菌标本室（MHYAU）和中科院微生物所真菌标本室（HMAS）。     

Molecular isolation and sequence determination of the cDNA for the mouse sperm-specific lactate dehydrogenase-X gene

Several cDNA clones for the mouse lactate dehydrogenase-X (LDH-X), a sperm-specific glycolytic enzyme, were isolated from mouse testicular cDNA libraries constructed in the bacteriophage vectors, lambda gt11 and gt10. The largest cDNA clone contains an insert of 1135 base pairs in length and an open reading frame that encodes a 332 amino acid polypeptide with a molecular weight of 35.89 kD. The deduced amino acid sequence of this protein is in close agreement with the published sequence of mouse LDH-X obtained by direct protein sequencing. Northern analysis of RNA isolated from different tissues detected a single size mRNA of 1.5 kilobases in mouse testis but not in brain or liver. The Ldh-x structural gene was estimated to be about 12 kb in size as demonstrated by Southern hybridization analysis of mouse genomic DNA using the full-length cDNA as a probe.     

Purification and characterization of human colony-stimulating factor 1 from human pancreatic carcinoma (MIA PaCa-2) cells

Colony-stimulating factor 1 (CSF-1) was purified from the serum-free conditioned medium of a human pancreatic carcinoma cell line (MIA PaCa-2) by a combination of conventional chromatography and high-performance liquid chromatography. The purity of human CSF-1 was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with a diffuse single band of Mr 42,000-50,000 and by N-terminal amino acid analysis of glutamate residue. The CSF-1 was stable at 50 degrees C for 30 min. It is sensitive to treatment with trypsin, chymotrypsin, and subtilisin but less sensitive to papain digestion. Treatment of CSF-1 with different glycosidases did not affect the biological activity. Sulfhydryl reagents such as dithiothreitol (DTT), iodoacetic acid, and N-ethylmaleimide did not affect the biological activity at the concentration of 1 mM. However, CSF-1 activity was inhibited totally by the combination of 10 mM DTT and 1 mM SDS. Under denaturing and reducing conditions, CSF-1 appeared on SDS-PAGE as a single protein band of Mr 21,000-25,000 and concurrently lost its activity, indicating that human CSF-1 possibly consists of two similar subunits and that the intact quaternary structure is essential for the biological activity. When treated with neuraminidase and endo-beta-D-N-acetylglucosaminidase D, the molecular weight of CSF-1 was reduced to 36,000-40,000, and to 18,000-20,000 in the presence of mercaptoethanol. Because of the specificity of endo-beta-D-N-acetylglucosaminidase D, it is suggested that the carbohydrate moieties are Asn-linked "complex-type" units.