O.S.S浅谈

Oncology Support System是荷兰PHI LIPS公司O.S.S的全称。这是一台在Treatment Planning System(T.P.S治疗计划系统)基础上发展而成、辅助CT诊断、设计三维放射治疗的专用计算机系统。我院放射治疗科于84年完成了SL 75—20医用电子直线加速器、模拟定位机、O.S.S等设备的安装     

枯草杆菌编码核糖体蛋白质S3、S5、S7、S12和S17的基因顺序

通过遗传转化和转导分析及核糖体蛋白质的双向凝肢电泳分析结果,表明编码枯草杆菌168核糖体30S小亚基五个核糖体蛋白质S3、S5、S7、S12和S17的基因顺序是rpsL-rpsC-rpsQ-rpsE-rpsG。     

大麦45S和5S rDNA定位及5S rDNA伸展纤维的FISH分析

用荧光原位杂交技术对45S和5SrDNA在大麦(Hordeum vulgare L．)有丝分裂中期染色体进行了确定分析,较强的45SrDNA信号共有2对,分别分布在大麦的第1染色体的短臂和第2染色体的长臂。而5SrDNA则只有1对杂交信号,位于第3染色体的长臂,但信号较弱。用伸展DNA纤维的荧光原位杂交(Fiber—FISH)技术测定了5SrDNA在大麦的基因组中的拷贝数,计算出5SrDNA的拷贝数约为408～416。对大麦品种中rDNA位点数目的可变性进行了讨论。     

基于12S,16S和28S rRNA基因序列的中国小毛瓢虫属系统发育分析

【目的】小毛瓢虫属Scymnus Kugelann昆虫主要捕食蚜虫、蚧虫等害虫,是一类经济上重要的天敌昆虫。目前针对小毛瓢虫属的系统发育研究尚属空白,亚属之间的系统演化关系尚不明确,为了建立合理的分类系统,亟需对小毛瓢虫属的亲缘关系进行研究和探讨。【方法】以华南农业大学馆藏的小毛瓢虫属5亚属共44种为研究对象,采用PCR技术对12S, 16S和28S rRNA基因的部分序列进行扩增;运用MEGA 7.0分析了小毛瓢虫属内12S, 16S和28S rRNA基因的碱基组成,基于K2P模型计算了小毛瓢虫属44种的种间遗传距离;采用最大似然法(maximum-likelihood, ML)和贝叶斯推断法(Bayesian-inference, BI)构建该属的系统发育树。【结果】扩增获得小毛瓢虫属44种的12S rRNA基因序列平均长度为356 bp, 16S rRNA基因序列平均长度为351 bp, 28S rRNA基因序列平均长度为315 bp;序列分析表明,12S rRNA基因的A, T, G和C平均含量分别为38.8%, 43.5%, 11.9%和5.8%, 16S rRNA基因的A, T, G和C平均含量分别为37.6%, 40.3%, 14.4%和7.7%, 28S rRNA基因的A, T, G和C平均含量分别为26.7%, 18.3%, 31.4%和23.5%;基于联合序列分析的种间遗传距离为0.004～0.276,平均遗传距离为0.115。系统发育分析结果表明,小毛瓢虫属为单系起源,而小毛瓢虫亚属Scymnus(Scymnus) Kugelann、毛瓢虫亚属Scymnus(Neopullus) Sasaji、小瓢虫亚属Scymnus(Pullus) Mulsant和拟小瓢虫亚属Scymnus(Parapullus) Yang均为并系起源。【结论】基于12S, 16S和28S rRNA基因序列的小毛瓢虫属系统发育分析显示传统的形态学分类体系与基于分子数据分析的结果部分不一致,这表明应该对该属内各亚属的鉴别特征进行全面检视,筛选并确立各亚属的形态指标,同时也表明该属内的亚属分类单元需重新厘定。     

短杆菌肽S的研究进展

短杆菌肽S是迄今为止研究得最详细的一种与细胞膜发生相互作用的环状肽类抗生素.它的作用机理是破坏细胞膜结构,导致细胞内含物的释放,而最终引起细胞的死亡.对短杆菌肽S的研究进展进行了综述.     

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蓖麻蚕核糖体核糖核酸基因上18S、28S和5.8S核糖体核糖核酸基因的定位

蓖麻蚕的核糖体核糖核酸(rRNA)的基因(rDNA)是多拷贝基因,其重复单位成线性方向排列。在每一重复单位中含有18S、28S和5.8S rRNA基因各一个。了解它们的排列状况是认识rDNA结构的基础。本文将无性繁殖的该rDNA用各种限制性内切酶水解后,制成Southern转移膜与放射性同位素标记的18S、28S和5.8S rRNA杂交;又将18S和28S rRNA制成Northern转移膜与放射性同位素标记的rDNA片段杂交,从而排出18S、28S和5.8S rRNA基因在rDNA上面的相对位置。     

洗衣粉S.S.琼脂培养基的初步应用报告

分离肠道病原菌的培养基种类繁多,但效果却不一致,其中效果较满意者当推3号胆盐S.S.琼脂及去氧胆酸钠-牛胆酸钠琼脂(简称郑氏S.S.琼脂)。我院试用的洗衣粉-去氧胆酸钠琼脂(简称洗衣粉S.S.琼脂)效果又较前者为优,这种培养基对肠道病原菌不但有很高的阳性检出率,而且痢疾杆菌在这种培养基上呈特殊的粘性菌落,可以在分离培养基上初步鉴别痢疾菌和沙门氏菌菌落,使肠道培养基更趋于完善。     

S100、S100α和S100β蛋白在乳腺癌中的表达及诊断意义

为了探讨Ｓ１００ 蛋白在乳腺癌表达的临床病理意义,采用Ｓ－Ｐ免疫组化法,检测了Ｓ１００ 和Ｓ１００α、Ｓ１００β和Ａｃｔｉｎ 在１１２ 例乳腺癌组织中的表达情况。发现Ｓ１００ 和Ｓ１００α在癌旁正常小叶和导管的肌上皮细胞中有明显表达, Ｓ１００β无表达。３ 种蛋白均可在癌细胞中表达, 表达的阳性率分别为８２．０６％ 、５７．９４％ 和６０．７４％ , Ｓ１００ 表达率明显高于Ｓ１００α和Ｓ１００β（Ｘ２＝ １４．１７, Ｐ＜ ０．０１）。Ａｃｔｉｎ 阳性率为２５．８９％ , 明显低于三种Ｓ１００ 蛋白（Ｘ２＝ ２９．８５, Ｐ＜ ０．０００１）。三种Ｓ１００蛋白的表达均与乳腺癌核分裂数、组织分级和淋巴结转移均无明显关系。研究显示乳腺癌Ｓ１００ 蛋白的表达不表明有肌上皮分化, Ｓ１００ 可作为乳腺癌的一种标志蛋白     

Chromosomal localization of 5S and 18S–5.8S–25S ribosomal DNA sites in five Asian pines using fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) was employed on mitotic metaphase chromosome preparations of five Asian Pinus species: Pinus tabuliformis, Pinus yunnanensis, Pinus densata, Pinus massoniana and Pinus merkusii, using simultaneously DNA probes of the 18S rRNA gene and the 5S rRNA gene including the non-transcribed spacer sequences. The number and location of 18S rDNA sites varied markedly (5-10 pairs of strong signals) among the five pines. A maximum of 20 major 18S rDNA sites was observed in the diploid genome (2n = 24) of P. massoniana. The 5S rDNA FISH pattern was less variable, with one major site and one minor site commonly observed in each species. The differentiation of rDNA sites on chromosomes among the five pines correlates well with their phylogenic positions in Pinus as reconstructed from other molecular data. P. densata, a species of hybrid origin, resembles its parents ( P. tabuliformis and P. yunnanensis), including some components characteristic of each parent in its pattern. However, the species is unique, showing new features resulting possibly from recombination and genome reorganization.     

Positions of the cytoplasmic end of BK α S0 helix relative to S1–S6 and of β1 TM1 and TM2 relative to S0–S6

The large-conductance, voltage- and Ca²⁺-gated K⁺ (BK) channel consists of four α subunits, which form a voltage- and Ca²⁺-gated channel, and up to four modulatory β subunits. The β1 subunit is expressed in smooth muscle, where it slows BK channel kinetics and shifts the conductance–voltage (G-V) curve to the left at [Ca²⁺] > 2 µM. In addition to the six transmembrane (TM) helices, S1–S6, conserved in all voltage-dependent K⁺ channels, BK α has a unique seventh TM helix, S0, which may contribute to the unusual rightward shift in the G-V curve of BK α in the absence of β1 and to a leftward shift in its presence. Such a role is supported by the close proximity of S0 to S3 and S4 in the voltage-sensing domain. Furthermore, on the extracellular side of the membrane, one of the two TM helices of β1, TM2, is adjacent to S0. We have now analyzed induced disulfide bond formation between substituted Cys residues on the cytoplasmic side of the membrane. There, in contrast, S0 is closest to the S2–S3 loop, from which position it is displaced on the addition of β1. The cytoplasmic ends of β1 TM1 and TM2 are adjacent and are located between the S2–S3 loop of one α subunit and S1 of a neighboring α subunit and are not adjacent to S0; i.e., S0 and TM2 have different trajectories through the membrane. In the absence of β1, 70% of disulfide bonding of W43C (S0) and L175C (S2–S3) has no effect on V₅₀ for activation, implying that the cytoplasmic end of S0 and the S2–S3 loop move in concert, if at all, during activation. Otherwise, linking them together in one state would obstruct the transition to the other state, which would certainly change V₅₀.     

Molecular analysis of 16S–23S spacer regions ofAcetobacter species

16S-23S rDNA internal transcribed spacer regions (ITS) similarities were determined in 8 Acetobacter and 1 Gluconacetobacter strains. ITS-PCR amplification of the 16S-23S spacers showed 2 products of similar size in 7 strains; only 1 product of similar size was found in the 2 remaining strains. Analysis of the PCR products using restriction endonucleases HaeIII, HpaII and AluI revealed 3 different restriction groups of A. pasteurianus for AluI and HaeIII, and 4 restriction groups for HpaII. ITS nucleotide sequences of all studied strains exhibited a 52-98% similarity.     

水稻45S rDNA和5S rDNA的染色体定位研究

45SrDNA和5SrDNA是水稻中与核糖体RNA合成有关的2个功能片段,有关这2个序列在水稻染色体上的位置,不同研究者的研究结果不尽相同,在获得水稻染色体清晰制片的基础上,通过FISH确定了45SrDNA序列位于水稻的第9号和第10号染色体的短臂末端,并且第9号染色体上的拷贝数多于第10号染色体,5SrDNA序列位于第11号染色体短臂靠近着丝点处。     

花生45S rDNA和5S rDNA的染色体定位研究

对四粒红和蜀花四号花生材料进行了核型分析,四粒红为2B核型,核型公式为2n=4x=40=38m＋2sm（4SAT）;蜀花四号为1B核型,核型公式为2n=4x=40=40 m（2SAT）。利用双色荧光原位杂交技术,对45S rDNA和5S rDNA这两个材料有丝分裂中期染色体上的物理位置进行了定位分析。定位结果表明,四粒红有6对45S rDNA位点,位于A2L、A7S、A9L、B3L、B7S、B8L（A和B分别代表基因组A和基因组B,L和S代表长臂和短臂,数字代表染色体序号,下同）;2对5S rDNA位点,位于A3S和B3S;蜀花四号有5对45S rDNA位点,位于A2L、A9L、B3L、B7S、B9L;2对5S rDNA位点,位于A3S和B3S。花生的45S rDNA位点具有可变性,5S rDNA则相对保守。