毛草龙化学成分及其细胞毒活性研究

为探究毛草龙(Ludwigia octovalvis)中的活性成分,该研究采用硅胶、Sephadex LH-20、C₁₈中低压和半制备液相等色谱方法对毛草龙的80%乙醇提取物进行分离纯化,根据理化性质及波谱数据鉴定化合物结构,并通过MTS法检测单体化合物对5种肿瘤细胞增殖的抑制活性。结果表明:(1)从毛草龙中分离得到20个化合物,分别鉴定为(-)-南烛木树脂酚(1)、8, 8''-bisdihydrosiringenin(2)、5-甲氧基-(-)-异落叶松脂素(3)、(-)-isolariciresinol(4)、3,4''-二甲氧基鞣花酸(5)、3,3'',4''-三甲氧基鞣花酸(6)、1,3,6-tri-O-galloyl-β-glucospyranose(7)、柯里拉京(8)、没食子酸甲酯(9)、没食子酸乙酯(10)、terminaliate A(11)、丁香酸(12)、3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone(13)、木犀草素(14)、山柰酚(15)、5,8-dihydroxy-7-methoxyflavone(16)、川陈皮素(17)、桔皮素(18)、α-托可醌(19)、5-O-(E)-p-coumaroyl quinic acid ethyl ester(20)。其中,化合物1-5、7、8、11、13、16-20为首次从该属植物中分离得到,化合物6、9、10、12、15为首次从该植物中分离得到。(2)化合物19对白血病HL-60细胞显示细胞毒活性,IC₅₀为10.31 μmol·L^-1; 化合物6-8、19对非小细胞肺癌细胞A549显示细胞毒活性,IC₅₀分别为25.82、42.05、36.94、17.54 μmol·L^-1; 化合物6、7、11、14、19对肝癌SMMC-7721显示细胞毒活性,IC₅₀分别为24.24、26.35、26.51、33.34、20.44 μmol·L^-1; 化合物6和化合物19对乳腺癌MDA-MB-231显示细胞毒活性,IC₅₀分别为34.91、21.13 μmol·L^-1; 化合物6、7、19对结肠癌SW480显示细胞毒活性,IC₅₀分别为36.03、39.97、5.52 μmol·L^-1。该研究结果丰富了毛草龙的化学成分,为毛草龙抗肿瘤活性研究奠定了基础。     

Microcalorimetric studies of the action of Na2SeO3 on the growth of Halobacterium halobium R1

The effect of Na₂SeO₃ on the growth of Halobacterium halobium R1 was investigated by means of microcalorimetry at 37°C. The biological response to toxicants is observed as the inhibition of the rate constant of growth of living cells. A low concentration of Na₂SeO₃ stimulated the growth of H. halobium R1, and a high concentration of Na₂SeO₃ inhibited the growth of H. halobium R1. Toxicity may be expressed as the half-inhibition concentration (IC₅₀). The rate constants of growth (k) and the concentrations of Na₂SeO₃ (c) shows a linear relationship: k=1.790 × 10⁻⁶ − 2.27 × 10⁻³ c. The value of IC₅₀ obtained from the accompanying figure of I-c is 679 μg/mL.     

铁筷子提取物对肿瘤细胞增殖及COX-2 mRNA表达的抑制作用

研究不同铁筷子提取物对肿瘤细胞增殖及 COX-2 mRNA 表达的抑制作用。以铁筷子醇总提取物(TKZ1)、正丁醇萃取部位(TKZ2)、乙酸乙酯萃取部位(TKZ3)分别作用于 DU145、PC3、HeLa、HT-29、HepG2等肿瘤细胞,应用噻唑蓝实验(MTT 法)计算其对细胞增殖的抑制作用,应用荧光定量 PCR 技术检测TKZ1、TKZ2、TKZ3处理后的各肿瘤细胞中 COX-2 mRNA 的表达情况。结果表明：TKZ1、TKZ2、TKZ3均能显著抑制多种肿瘤细胞的增殖,与阴性对照组比较,其可以在 mRNA 水平上抑制 COX-2的表达,且呈明显的量效关系。说明铁筷子提取物对体外肿瘤细胞的增殖具有显著的抑制作用,其抗瘤机制可能与抑制肿瘤细胞中 COX-2 mRNA 的表达有关。     

超氧化物歧化酶模拟化合物的生物活性研究

根据天然超氧化物歧化酶(SOD)活性部位结构合成了含苯并咪唑的5种配体及其32种分别含Cu（Ⅱ）、Fe（Ⅲ）、Mn（Ⅱ）、Co（Ⅱ）的模拟化合物.经光谱、电化学测试证明这些化合物具有拟S3D活性,其50％抑制率浓度（IC50）为10-6～10-8mol·L-1,催化超氧离子自由基（O-·2）歧化的反应速率常数kq为106～108mol-1·L·s-1.同时观察到几种模拟化合物有抗肿瘤活性或增强水稻抗寒性.     

渗透胁迫和离子毒害对转Bt基因棉幼苗生长及离子分布的影响

研究了渗透和盐胁迫处理对转Bt基因抗虫棉(Gossypium hirsutum) 99B种子的萌发和幼苗生长的影响,以及幼苗不同器官离子吸收和分配的差异。结果表明:渗透和盐胁迫均对转Bt基因抗虫棉幼苗的生长有抑制作用,其中PEG的抑制作用最强,而3种盐的抑制程度以CaCl₂>NaCl>Na₂SO₄,且在Na⁺含量相同时,Cl^-的毒害大于SO₄^2-。渗透胁迫下使根、茎和叶中的Na⁺和Cl^-含量提高,K⁺、Ca²⁺、SO₄^2-含量和K⁺/Na⁺、Ca²⁺/Na⁺和SO₄^2-/Cl^-比值降低,且地上部的变化幅度大于地下部的,其中以PEG的影响最为显著,其次是CaCl₂,Na₂SO₄处理最弱。这些说明,转Bt基因抗虫棉99B的耐盐性较弱。     

桐花树活性内生真菌筛选及其抗菌化学成分的研究

为了探究桐花树内生真菌在抑菌方面的价值,该文以内生真菌发酵产物的抑菌作用为评价指标筛选活性菌株,采用生物活性跟踪方法结合多种色谱技术分离活性菌株的化学成分,通过波谱与文献数据比对鉴定单体化合物结构,并利用微孔板法测定单体化合物的抑菌活性。结果表明:(1)从桐花树分离得到的16株内生真菌分属2纲7目10科10属,镰刀菌属(Fusarium)为优势菌属。内生真菌GXIMD02029和GXIMD02039的发酵产物对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌、藤黄微球菌、粘性放线菌和金黄色葡萄球菌有不同程度的抑制作用,GXIMD02038发酵产物对耐甲氧西林金黄色葡萄球菌、藤黄微球菌和金黄色葡萄球菌有抑制作用。(2)7个化合物从内生真菌Phomopsis sp. GXIMD02029中被分离并鉴定为(15R)-acetoxydothiorelone A(1)、cytosporone B(2)、pestalotiopsone H(3)、pestalotiopsone B(4)、4-Hydroxybenzaldehyde(5)、p-Hydroxybenzoic acid(6)、N-(2-phenylethyl)acetamide(7)。(3)化合物1和2有不同程度的抑菌作用,化合物1对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌的MIC值为16.25 SymbolmA@ g·mL^-1,对藤黄微球菌和粘性放线菌的MIC值为7.812 5 SymbolmA@ g·mL^-1,对金黄色葡萄球菌的MIC值为31.25 SymbolmA@ g·mL^-1。化合物2对藤黄微球菌的MIC值为62.5 SymbolmA@ g·mL^-1,对枯草芽孢杆菌、表皮葡萄球菌、耐甲氧西林金黄色葡萄球菌、粘性放线菌的MIC值为125 SymbolmA@ g·mL^-1,对金黄色葡萄球菌的MIC值为250 SymbolmA@ g·mL^-1。该文筛选了3株活性菌株,首次报道化合物1具有抗菌活性,为桐花树内生真菌在抗菌价值方面提供了依据。     

苄基异喹啉类化合物 D20抑制钙调素激活磷酸二酯酶的研究

苄基异喹啉化合物是一类钙调素拮抗剂.对新合成的双苄基异喹啉化合物 D₂₀对钙调素依赖的磷酸二酯酶的抑制作用进行了研究,IC₅₀=5μmol/L,表明其拮抗作用大于三氟啦嗪,是强的拮抗剂.荧光分析表明,钙调素与化合物 D₂₀的结合常数为2.64(μmol/L)^-1,一个化合物 D₂₀分子与两个钙调素分子结合,并显示了结合方向性及空间位阻影响.     

碳酸氢盐处理下桑树和构树的生长、光合和抗逆性差异

为探究喀斯特生境中,在碳酸氢盐的胁迫下HCO^-₃对植株生长及生理特性的影响,该文以构树和桑树幼苗为研究对象,对不同浓度NaHCO₃溶液(0、15、30 mmol·L^-1)处理下植株的生长情况、光合能力、抗氧化酶活性、渗透调节物质含量和细胞膜系统损伤情况进行研究。结果表明:(1)在HCO^-₃处理下,构树和桑树的生长和光合能力均受到抑制,叶片细胞内均发生显著的抗氧化和抗渗透胁迫生理响应。(2)HCO^-₃对构树和桑树生长的抑制作用与其浓度有关,并有显著差异性(P<0.05)。(3)30 mmol·L^-1 HCO^-₃处理对植株生长、光合、抗氧化酶系统和渗透调节系统的抑制作用以及植物细胞的损伤情况要显著强于15 mmol·L^-1 HCO^-₃处理的效果。(4)同等浓度的HCO^-₃处理下,构树的生长、光合能力、抗氧化酶活性、渗透调节物质含量显著高于桑树,其叶片细胞损伤情况显著低于桑树。综上结果均表明,构树对碳酸氢盐胁迫的耐受能力要优于桑树。该研究为阐明桑科植物对喀斯特环境适应机制提供科学支撑。     

干旱条件下外源蔗糖对高表达玉米C4型pepc水稻种子萌发的影响

为揭示外源蔗糖参与干旱胁迫下高表达转玉米C₄ 型磷酸烯醇式丙酮酸羧化酶(phosphoenolpyruvate carboxylase, PEPC)基因(C₄ pepc)水稻(简称：PC)种子萌发的生理机制,该研究以 PC及其未转基因野生型受体‘Kitaake’(简称：WT)的种子为材料,研究外施不同浓度蔗糖联合模拟干旱(10% PEG 6000)处理下,其种子发芽参数、总可溶性糖及可溶性蛋白含量、蔗糖非发酵1 (sucrose nonfermenting 1, SNF1)相关蛋白激酶(SNF1 related protein kinase 1s, SnRK1s)基因以及PEPC基因表达等参数的变化。结果表明：(1)PEG 6000模拟干旱处理均显著抑制两材料发芽,但明显促进胚根的生长;外施蔗糖则呈现浓度效应,高浓度蔗糖(>150 mmol·L^-1)进一步加剧了干旱对发芽的抑制效应,而低浓度(<30 mmol·L^-1)则可缓解干旱的抑制,但与WT(<30 mmol·L^-1)相比,促进PC水稻萌发的外施蔗糖浓度(<6 mmol·L^-1)更低,且各处理的发芽表现与其α 淀粉酶活性的动态表现一致。(2)与WT相比,外施3 mmol·L^-1蔗糖联合干旱处理下,显著提高了PC种子的发芽率,且伴随PC内源蔗糖含量、总可溶糖和可溶性蛋白含量显著增加;且外施3 mmol·L^-1蔗糖使PC中内源C₃ pepc基因表达下调,而外源导入C₄ pepc基因表达显著增加。(3)与WT相比,干旱处理下外施3 mmol·L^-1蔗糖,PC的糖信号相关基因SnRKs亚家族基因(包括SnRK1s：OsK1a OsK24 OsK35和SnRK2s:SAPK6)的表达也显著增加。研究发现,外施低浓度蔗糖通过上调PC水稻种子中可溶性糖和可溶性蛋白含量,增强SnRK1s亚家族基因和外源C₄ pepc基因的表达,提高了α 淀粉酶活性,从而缓解了干旱胁迫对PC种子萌发的抑制。     

有机锗对巨噬细胞激活与磷脂代谢转换的影响

有机锗(CGS、DGS、Ge-132)于活体内能激活小鼠腹腔巨噬细胞(Mφ),后者于体外对肿瘤细胞Hca-16H₃和J6-2表达Mφ介导的肿瘤细胞毒(MTC),CGS与DGS的激活效应高于Ge-132,CGS为最强.它们激活的Mφ磷脂PC代谢转换较常驻Mφ(R-Mφ)明显增高,表现在［³H］胆碱掺入PC增加,CGS的增加效应最强.Ge-132激活的Mφ(Ge-12-Mφ)与R-Mφ比较,增加［³²P］Pi掺入PC,降低［³²P］Pi或［³H］肌醇掺入PI,但［³²P］Pi或［³H］肌醇掺入PIP、PIP₂未有显著差异.PC代谢转换的增加很可能是有机锗激活Mφ表达MTC的信息传递所需要的.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.