Human DNA helicase IV is nucleolin, an RNA helicase modulated by phosphorylation

The cDNA encoding human DNA helicase IV (HDH IV), a 100-kDa protein which unwinds DNA in the 5′ to 3′ direction with respect to the bound strand, was cloned and sequenced. It was found to be identical to the human cDNA encoding nucleolin, a ubiquitous eukaryotic protein essential for pre-ribosome assembly. HDH IV/nucleolin can unwind RNA-RNA duplexes, as well as DNA-DNA and DNA-RNA duplexes. Phosphorylation of HDH IV/nucleolin by cdc2 kinase and casein kinase II enhanced its unwinding activity in an additive way. The Gly-rich C-terminal domain possesses a limited ATP-dependent duplex-unwinding activity which contributes to the helicase activity of HDH IV/nucleolin.     

猕猴桃种质资源保存及育种研究

收集保存猕猴桃属植物３５种或变种、变型,并将它们分为抗寒?喜凉、喜温３种类型。从保存的中华猕猴桃优株中系统选育出“武植２号”、“武植３号”２个优良品种。以中华猕猴桃为母本,毛花猕猴桃为父本进行种间杂交,从杂种Ｆ１代中培养出“江山娇”、“满天星”、“重瓣”３个具有园艺观赏价值的优良株系。这些研究工作为猕猴桃种质资源的保存及新品种的培育奠定了工作基础。     

兰属(Cymbidium)5种植物叶结构特征

采用光学显微镜和体视镜,对兰属5种植物（春兰、蕙兰、建兰、寒兰、墨兰）的叶结构特征（叶脉结构、叶表皮结构、解剖结构）进行了观察和测量。结果显示,兰属5种植物的叶脉结构相似,叶表皮结构和解剖结构存在较大差异,其中最主要的差异是皮下纤维束的多少和边缘角质层锯齿形态。依据叶结构特征聚类分析结果,5种兰可分为春兰组、建兰组和墨兰组3组。本研究表明叶结构特征对兰属5种植物的分类具有重要意义。     

木姜子叶精油的化学成分研究

采用气相色谱-质谱联用仪对产于秦岭太白山的木姜子叶的挥发油成分进行分析鉴定,从分离出的79个峰中鉴定了32种成分,其含量占挥发油总量的90.59％,主要成分为1,3,3-三甲基-乙-氧杂双环[2,2,2]辛烷(59.96％),1,8-桉油醇(8.96％),香茅醛(6.86％),2-甲基-5-(1-甲基乙烯基)环己酮(4.34％)和澄花醇乙酯(3.19％)。     

江苏省海滩植被演替的研究

江苏省海滩植被可分为滨海盐土植被、盐沼植被及海滩沙生植被三个基本类型。本文论述了这些植被类型的演替规律。滨海盐土植被与盐沼植被的演替,外因于土壤盐分含量递减与有机质含量的递增;海滩沙生植被的演替,外因于土壤沙颗粒大小及其相应的土壤含水量的变化,所以海滩植被演替为外因动态演替。     

荧光显微镜观察大蒜油对腹水癌细胞的影响

用吖啶橙染色,荧光显微镜观察大蒜油对—S180,昆明小鼠,U14 C57BL/6J小鼠和L1210DBA小鼠的癌细胞作用的影响,结果表明大蒜油有直接破坏癌细胞的DNA,RNA和分裂中期染色体的作用。给药后2—6小时作用最强,12小时后癌细胞数逐渐恢复,因此给药间隔不应超过12小时。我们研究证实大蒜油有明显的抗癌作用,为临床应用提供有力的依据。     

Expression of a gene encoding a rabbit sperm membrane protein in mammalian cells.

A general mammalian expression vector designated pSV2-EP was reconstructed by inserting an oligonucleotide fragment into pSV2-dhfr. This vector allowed insertion of cDNAs with EcoRI cohesive ends. The pSV2-EP contains a simian virus 40 (SV40) early promoter, origin for DNA replication, SV40 poly-A site, splicing site, an initiator ATG downstream from the promoter and an EcoRI site for the insertion of cDNA fragment screened from lambda gt11 expression libraries. A recombinant plasmid (pS-VRS-1) was constructed by inserting RSD-1, a cDNA encoding a rabbit sperm tail protein, into the EcoRI site of the pSV2-EP vector. Chinese hamster ovarian (CHO) dhfr-negative cells were cotransformed with pSV2-dhfr and pSVRS-1 by the calcium phosphate method. In selective culture medium without thymidine and hypoxanthine, several cell lines were obtained containing mRNA and DNA that hybridized with RSD-1. One of these transformed cell lines stained intensely with anti-rSMP-B antibodies, demonstrating that the RSD-1 was expressed in the transformed CHO cells.     

元谋新第三纪食肉动物化石的初步观察

本文对云南元谋盆地产古猿化石地点的部分食肉类化石进行了初步观察分类,认为它们的时代似应稍晚于禄丰,相当上新世早期,估计距今5-6百万年.     

Relation between veratridine reaction dynamics and macroscopic Na current in single cardiac cells

Veratridine modification of Na current was examined in single dissociated ventricular myocytes from late-fetal rats. Extracellularly applied veratridine reduced peak Na current and induced a noninactivating current during the depolarizing pulse and an inward tail current that decayed exponentially (tau = 226 ms) after repolarization. The effect was quantitated as tail current amplitude, Itail (measured 10 ms after repolarization), relative to the maximum amplitude induced by a combination of 100 microM veratridine and 1 microM BDF 9145 (which removes inactivation) in the same cell. Saturation curves for Itail were predicted on the assumption of reversible veratridine binding to open Na channels during the pulse with reaction rate constants determined previously in the same type of cell at single Na channels comodified with BDF 9145. Experimental relationships between veratridine concentration and Itail confirmed those predicted by showing (a) half-maximum effect near 60 microM veratridine and no saturation up to 300 microM in cells with normally inactivating Na channels, and (b) half-maximum effect near 3.5 microM and saturation at 30 microM in cells treated with BDF 9145. Due to its known suppressive effect on single channel conductance, veratridine induced a progressive, but partial reduction of noninactivating Na current during the 50-ms depolarizations in the presence of BDF 9145, the kinetics of which were consistent with veratridine association kinetics in showing a decrease in time constant from 57 to 22 and 11 ms, when veratridine concentration was raised from 3 to 10 and 30 microM, respectively. As predicted for a dissociation process, the tail current time constant was insensitive to veratridine concentration in the range from 1 to 300 microM. In conclusion, we have shown that macroscopic Na current of a veratridine-treated cardiomyocyte can be quantitatively predicted on the assumption of a direct relationship between veratridine binding dynamics and Na current and as such can be successfully used to analyze molecular properties of the veratridine receptor site at the cardiac Na channel.