Callus formation from protoplasts of Artemisia sphaerocephala Krasch and some factors influencing protoplast division

Round wormwood (Artemisia sphaerocephala Krasch) seeds were germinated on Murashige & Skoog (1962) medium without plant growth regulators. The hypocotyls of seedlings were sliced and cultured on M1 medium with 2,4-dichlorophenoxyacetic acid (9.05 M) to induce callus. The induced calluses were subcultured on the same medium. Ten day old calluses were used to isolate protoplasts in an enzyme solution with 0.65 M mannitol. Protoplast yield strongly depended upon the state of callus cultures. Certain amount of hemicellulase could improve protoplast isolation. Purified protoplasts were cultured in modified Kao & Michayluk (1975) medium with 0.60 M mannitol as osmoticum, suggesting that protoplasts of A. sphaerocephala need a high initial osmolarity. Protoplasts generally divided evenly and the percentage of first division could reach 10%. Kinetin exhibited a positive effect on initial cell division. Furthermore, we studied the effect of protoplast density and vitamin C on sustained growth of protoplasts. After forty days, 1 mm calluses in diameter formed.Abbreviations CH casein hydrolysate - 2,4-D 2,4-dichlorophenoxyacetic acid - KM8P Kao & Michayluk (1975) protoplast medium - MS Murashige & Skoog (1962) medium - MES-2 (N-morpholino)ethanesulfonic acid     

Variation of 423G>T in the Agouti Gene Exon 4 in Indigenous Chinese Goat Breeds

The Agouti gene plays an important role in pigment synthesis in domestic animals. A transversion of 423G>T recognized by BanII was found after a fragment (178 bp) of the goat Agouti gene exon 4 was amplified and sequenced. To investigate its genetic effect and diversity, 677 individuals from 12 indigenous Chinese goat breeds and one imported goat breed from South Africa (Boer goat) were analyzed by PCR-RFLP. Two alleles, T and G, and three genotypes, TT, TG, and GG, were detected. Allele T had a higher frequency in most goat breeds and, combined with the coat color phenotype, is believed to be responsible for the black phenotype or to be linked with the causative site in the goat. The results also indicate that the 423G>T transversion showed lower genetic diversity in goat breeds with black coat color in China. Genetic differentiation among the 13 goat populations was 0.2023. The clustering of populations based on the 423G>T site was basically consistent with the variation of coat color.     

沙葱(Allium mongolicum Regel)离体培养再生可育植株

以沙葱（Allium mongolicum Regel)的叶基切段作外植体,成功地诱导出愈伤组织和再生植株。诱导愈僵组织的培养基为附加2mgL^-22,4-D和0.2mgL^-1KT的MS培养基。愈伤组织转移到附加2mgL^-16BA和0.4mgL^-1NAA的MS培养基后分化出大量的苗;分化苗在含有IBA1mgL^-1的1/2MS培养基上生根最佳。再生植株移栽成活率在95%以上。移栽到田间的植株第二年以后可正常开花结实。     

甘薯质体中的乙酰辅酶A羧化酶亚基基因accD的克隆与序列分析

依据烟草质体全基因组序列设计引物,以甘薯质体基因组DNA为模板,PCR扩增包含质体accD基因完整编码区在内的一段序列（GenBank登录号为GQ395771）。序列分析表明：该片段全长为2209bp,包括1548bp的nccD基因编码序列,推测编码515个氨基酸的蛋白质,该蛋白序列具有异质型β-CT中保守的锌指结构和C末端5个基元。同时绘制了该DNA片段的限制性酶切图谱。相似性比较显示,甘薯accD基因与大豆、马铃薯、拟南芥、人参、莴苣、葡萄、海岛棉、甘蓝、辣椒、菠菜、番茄和烟草的accD基因核苷酸相似性为72％-87％,氨基酸相似性为58％-83％。     

野猪、家猪及野家杂种猪Leptin基因2、3外显子的SNPs分析

Leptin是一种内分泌激素（167个氨基酸）,主要在脂肪组织中表达,通过下丘脑对机体内能量的消耗和摄取起着重要的调节作用^[1]。鉴于此本文对野猪、家猪及野家杂种猪Leptin的2、3外显子进行了SNPs分析,并检测到了多态性。对纯合子片段进行克隆和测序,结果表明在编码区的214位碱基由T突变为C,编码的氨基酸没有发生改变;364位碱基由C突变为G,365位碱基由G突变为C,编码的Arg转变为Ala;426位由G突变为A,编码的氨基酸没有发生改变;451位插入碱基T,造成移码突变;462位由G突变为T。     

甘薯叶绿体rbcL基因的克隆与序列分析

根据烟草、水稻和菠菜叶绿体的全基因组序列设计引物,以甘薯的叶绿体基因组DNA为模板,PCR扩增包舍甘暑叶绿体rbcL完整基因(GenBank登录号为AY942199)在内的一段序列.序列分析表明:此片段的全长为1 627 bp,包括1 443bp的编码区序列在内.推测编码480个氨基酸,同时构建了此片段的限制性酶切图谱.相似性比较显示,此基因编码区序列与烟草、菠菜、小麦、水稻、玉米、矮牵牛、紫花苜蓿、拟南芥、莨菪、葡萄以及甜菜的rbcL基因核苷酸的同源性为85%～98%,氨基酸的同源性为92%～95%.     

胰岛素对PC12细胞神经型一氧化氮合酶表达及活性的影响

为探讨胰岛素对神经细胞中神经型一氧化氮合酶（nNOS）的表达及活性的影响,应用流式细胞术、原位杂交、电子自旋共振等技术方法研究胰岛素对PC12细胞中神经型一氧化氮合酶的影响.胰岛素作用PC12细胞9 h 后,神经型一氧化氮合酶的免疫荧光强度显著升高,且呈浓度依赖关系,其最大效应为对照的(155±13)%(P＜0.01, n=3, t-test).加入胰岛素(16 mU/L, 6 h)也能够显著上调nNOS mRNA的表达,为对照的(182±13)%(P＜0.01, n=3, t-test).另外加入胰岛素(16 mU/L)作用9 h后,神经型一氧化氮合酶的活性也显著升高,为对照的(167±15)%(P＜0.01, n=4, t-test).由上述结果可知,胰岛素对PC12细胞的神经型一氧化氮合酶的表达及活性有上调作用.     

砷对蓝藻光合作用和细胞生长的影响

在世界的许多地方, 砷污染是一个严重的问题, 尤其是水体中的污染程度更加严重。砷主要以As( V) 和As( ó ) 形式存在。由于AsO43- 在结构上与PO43-很相似, 它通过磷转运途径进入细胞, 因此砷的毒性主要是源于对磷代谢的干扰1 。砷对于人和动物的危害性是人所共知的, 它会引发细胞凋亡, 导致多种组织和器官发生癌变, 从而引起死亡。但是砷对于水体生态系统中的重要类群) 藻类的生理和生长的影响报道较少。       

Spectroscopic Comparison of Different DNA Structures Formed by Oligonucleotides

Abstract

Six different nucleic acid structures including duplex, triplex and quadruplex are formed by oligonucleotides. Their structural properties are studied in detail by four spectroscopic techniques, i.e. CD, UV, NMR and fluorescence. Results are: CD Spectra: The common characteristics is a negative band at 240 nm, and the spectra are different from each other in the range 260–300 nm. Many factors such as chain direction, sugar puckering, orientation of the glycosyl bond, base stacking and sequence can effect their conformation and then show diversity and complexity in the spectra. UV Spectra: The UV spectra of all forms are quite similar, all of them exhibit a sharp positive peak around 210 nm and a broad positive band in the region of 240–280 nm. Although the bands are different in absorbance, the spectra are not characteristic enough to distinguish these forms. In addition, their thermal denaturation is also observed by UV spectrum, different melting curves and points are shown and some thermodynamic information is provided. NMR Spectra: Since the G residues in the six samples all participate in hydrogen bond, the imino proton can not exchange with the solvent freely so as to allow an observable resonance to arise. The resonance number and chemical shift will vary with the change in base-pairing number and mode as well as the whole geometry of its molecule. Fluorescence Spectra: The interaction mechanisms between EB and these structures are different. B type duplex and triplex adopt an intercalative mode in which the efficiency of energy transfer is relatively high and the fluorescence of EB can not be quenched easily. While for the parallel duplex, outside binding is predominant in which energy transfer can hardly happen and most of its fluorescence can be quenched. As for the quadruplex, groove binding is possible, so the efficiency of energy transfer is higher than that in outside binding, but lower than that in intercalative binding, and fluorescence is quenched partly.