4种红豆杉属植物遗传多样性和遗传关系的RAPD分析

采用RAPD标记研究了分属于4种红豆杉属(Taxus Linn.)植物的68个单株的遗传多样性,并采用UPGMA方法分析68个单株的遗传关系.结果表明:12条RAPD引物共扩增出109条带,其中多态性条带108条,多态性条带百分率为99.1％;平均每条引物扩增出9.1条带.南方红豆杉[T.wallichiana var.mairei (Lemée et Lévl)L.K.Fu et Nan Li.]种内的多态性条带百分率和观察等位基因数均最高;欧洲红豆杉(T.baccata Linn.)种内的有效等位基因数、Nei's基因多样度和Shannon's信息指数均最高;须弥红豆杉(T.wallichiana Zucc.)种内的各项遗传多样性指数均最低.供试4种植物的种内遗传多样度、种间遗传多样度、基因流和种间遗传分化系数分别为0.1745、0.358 6、0.401 7和0.554 5,表明55.45％的遗传变异发生在种间.南方红豆杉和须弥红豆杉遗传距离最近;曼地亚红豆杉(Taxus×media Rehd.)和须弥红豆杉的遗传距离最远.通过聚类分析可将68个单株分为3组,欧洲红豆杉的18个单株和曼地亚红豆杉的18个单株分别各自聚为1组;须弥红豆杉的16个单株和南方红豆杉的16个单株聚为1组,其中须弥红豆杉的16个单株和南方红豆杉的16个单株又各自聚为1个亚组,且南方红豆杉的雌、雄单株也分别聚在同一分支上,表明须弥红豆杉和南方红豆杉遗传关系较近,而欧洲红豆杉与其他3种植物的遗传关系较远.     

Dieckol,a natural polyphenolic drug,inhibits the proliferation and migration of colon cancer cells by inhibiting PI3K,AKT, and mTOR phosphorylation

This study investigated that dieckol (DKL), a natural drug, inhibits colon cancer cell proliferation and migration by inhibiting phosphoinositide-3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) phosphorylation in HCT-116 cells. The cells were treated with DKL in various concentrations (32 and 50 μM) for 24 h and then analyzed for various experiments. MTT (tetrazolium bromide) and crystal violet assay investigated DKL-mediated cytotoxicity. Dichlorodihydrofluorescein diacetate staining was used to assess the reactive oxygen species (ROS) measurement, and apoptotic changes were studied by dual acridine orange and ethidium bromide staining. Protein expression of cell survival, cell cycle, proliferation, and apoptosis protein was evaluated by western blot analysis. Results indicated that DKL produces significant cytotoxicity in HCT-116, and the half-maximal inhibitory concentration was found to be 32 μM for 24-h incubation. Moreover, effective production of ROS and enhanced apoptotic signs were observed upon DKL treatment in HCT-116. DKL induces the expression of phosphorylated PI3K, AKT, and mToR-associated enhanced expression of cyclin-D1, proliferating cell nuclear antigen, cyclin-dependent kinase (CDK)-4, CDK-6, and Bcl-2 in HCT-116. In addition, proapoptotic proteins such as Bax, caspase-9, and caspase-3 were significantly enhanced by DKL treatment in HCT-116. Hence, DKL has been considered a chemotherapeutic drug by impeding the expression of PI3K-, AKT-, and mTOR-mediated inhibition of proliferation and cell cycle-regulating proteins.     

青藏高原三个盐碱湖的产甲烷菌群和产甲烷代谢途径分析

【目的】分析青藏高原不同类型盐碱湖中的优势产甲烷菌群和优势产甲烷代谢途径。【方法】以不同盐度和植被类型的公珠错、昆仲错和无植被的兹格塘错的沉积物为研究对象,通过高通量测序和q PCR定量古菌16S r RNA多样性分析优势古菌类群;模拟原位盐浓度及p H,比较不同产甲烷底物(甲醇、三甲胺、乙酸和H_2/CO_2)富集沉积物的产甲烷速率,分析其优势产甲烷菌代谢类型。通过添加产甲烷抑制剂(2-溴乙烷磺酸盐),检测沉积物中产甲烷底物积累,确定不同盐碱湖中主要的产甲烷途径。【结果】昆仲错的优势菌群包括甲基/乙酸型的甲烷八叠球菌科(Methanosarcinaceae,11%),乙酸型的甲烷鬃菌科(Methanosaetaceae,7.9%)和氢型甲烷菌甲烷杆菌目(Methanomicrobiales,7.4%);公珠错和兹格塘错的优势菌群为甲烷鬃菌科(Methanosaetaceae)分别占15%和15.3%,及甲烷杆菌属(Methanobacterium)和甲基型的甲烷叶菌属(Methanolobus)。公珠错和昆仲错分别以乙酸和甲醇产甲烷速率最高,而兹格塘错从不同底物产甲烷速率无差异。抑制甲烷产生后,公珠错主要积累乙酸,昆仲错主要积累甲醇;兹格塘错不仅甲烷排放低,也无产甲烷物质显著积累。【结论】昆仲错沉积物中的甲烷主要来自甲醇,公珠错中的甲烷主要来自乙酸,而兹格塘错产甲烷和底物积累不活跃。因而推测高原盐碱湖主要的产甲烷途径和菌群可能与周围植被类型的相关性更高,而与盐度的直接相关性较低。     

Electrically Control Lateral Shift Owning to Guided-Wave Surface Plasmon Resonance with a Lithium Niobate Prism

Electrically controlled lateral shift by an electro-optic crystal prism is studied theoretically. The resonance point of excitation of guided-wave surface plasmon resonance (GWSPR) can be controlled by altering the refractive index of the prism. That is to say, the positions corresponding to the least reflectivity and the largest lateral shift could be conveniently modulated while the lithium niobate prism is operated in an external electric field. The maximal lateral shift is obtained at the excitation of GWSPR when the thickness of the silver film is optimized. The results of numerical simulations confirm theoretical calculation.

     

Phosphorylation of elongation factor-2 kinase differentially regulates the enzyme's stability under stress conditions

Chronic infection with hepatitis B virus (HBV) is associated with the majority of cases of hepatocellular carcinoma (HCC) in China. Despite this, there is no effective method for the early detection of HBV-induced liver cancer. Aberrant fucosylation is known to occur during the development of HCC. We, therefore, developed a method of applying matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze the relationship between aberrant fucosylation, tumor genesis and progression of HBV-associated HCC, and to establish proteomic profiling of serum for early diagnosis of HCC. The MALDI-TOF MS was based on Lens culinaris agglutinin (LCA) lectin magnetic beads and their affinity for separation. The method was applied initially to a 'training' cohort of 111 serum samples obtained from subjects in China with no liver disease (n=26), chronic hepatitis B without cirrhosis (n=21), HBV-infected cirrhosis (n=32), or HBV-infected HCC (n=32). In contrast to previous findings, the results of our profiling analysis demonstrated defucosylation on some of the glycoproteins involved in HCC. HCC was then diagnostically classified in a 'blind test' cohort (n=96). In this group we demonstrated that, HCC could be distinguished from all serum samples, HBV-associated chronic liver disease, and HBV-associated cirrhosis with a sensitivity/specificity of 70%/70%, 78%/74%, and 81%/82%, respectively. When combined with serum alpha-fetoprotein detection (AFP>20 ng/mL), the sensitivity/specificity improved to 78%/88%, 85%/88%, and 89%/91%, respectively. In conclusion, serum glycoprotein fucosylation abnormalities have diverse forms in patients with HCC. MALDI-TOF MS profiling of aberrant serum fucosylated glycoproteins distinguished HCC from controls with high accuracy.     

Autotaxin and its product lysophosphatidic acid suppress brown adipose differentiation and promote diet-induced obesity in mice

Brown adipose tissue is a thermogenic organ that dissipates stored energy as heat to maintain body temperature. This process may also provide protection from development of diet-induced obesity. We report that the bioactive lipid mediator lysophosphatidic acid (LPA) markedly decreases differentiation of cultured primary brown adipocyte precursors, whereas potent selective inhibitors of the LPA-generating enzyme autotaxin (ATX) promote differentiation. Transgenic mice overexpressing ATX exhibit reduced expression of brown adipose tissue-related genes in peripheral white adipose tissue and accumulate significantly more fat than wild-type controls when fed a high-fat diet. Our results indicate that ATX and its product LPA are physiologically relevant negative regulators of brown fat adipogenesis and are consistent with a model in which a decrease in mature peripheral brown adipose tissue results in increased susceptibility to diet-induced obesity in mice.     

Morphological and molecular characterization of fertile tetraploid somatic hybrids produced by protoplast electrofusion and PEG-induced fusion between Lycopersicon esculentum Mill. and Lycopersicon peruvianum Mill.

Summary Mesophyl protoplasts of two genotypes of cultivated tomato (Lycopersicon esculentum Mill.) and one of its wild relative species (Lycopersicon peruvianum Mill.) were fused by using electrofusion and polyethyleneglycol-induced fusion. Forty-three fertile tetraploid somatic hybrid plants, each deriving from separate calli, were recovered from both fusion procedures. Electrofusion appeared more efficient than chemical fusion for the production of somatic hybrids. These plants appeared morphologically similar, whatever the fusion procedure and tomato genotype. They had intermediate leaf, inflorescence, and flower morphology. After self-pollination, the hybrids set fruit of intermediate size and color. The hybrid nature of these plants was confirmed by isoelectric focusing of the Rubisco small subunits used as nuclear markers. L. esculentum and L. peruvianum were distinguished by means of two chloroplast markers: CF1-ATPase subunit as analyzed by isoelectro-focusing and ct DNA restriction patterns. All hybrids displayed both ct markers of only one parent with no biased transmission. Mitochondrial (mt) DNAs were prepared from flower buds by using miniaturized CsCl gradients. Preliminary analysis indicated that mt genomes from the hybrids all differed from those of both parents. mt DNA Sall restriction enzyme analysis revealed that all but two hybrids contained one novel fragment of 13.5 kb. Gene mapping experiments showed that the mt apocytochrome b and ATPase subunit 9 homologies in the somatic hybrid mt DNA resembled L. esculentum and L. peruvianum, respectively; the mt nad5 probe distinguished at least four distinct patterns in the hybrids. These results indicated that mt DNA rearrangements involving intergenomic recombinations occurred through protoplast fusion. A greater mt DNA polymorphism was induced with chemical fusion than with electrofusion.     

Combinatorial and synergistic properties of CaMV 35S enhancer subdomains.

We have analyzed expression conferred by five subdomains of the cauliflower mosaic virus (CaMV) 35S enhancer in mature transgenic plants. Expression was detected from subdomains that gave no expression at earlier stages of development indicating developmental regulation of expression and confirming the modular organization of the enhancer. In several cases the expression patterns are highly restricted in cell type, providing useful markers for developmental studies. Comparison of expression patterns conferred by various combinations of 35S enhancer cis-elements suggests that synergistic interactions among cis-elements may play an important role in defining tissue-specific expression. This has implications for the nature of a cis-element combinatorial code that could define expression throughout development.