中国人精母细胞中XY配对形态和行为的研究

运用表面铺展硝酸银染色联会复合体的电镜技术，对中国人精母细胞中XY配对形态和行为进行电镜观察，根据XY配对复杂形态和行为变化将XY配对分为六个阶段，XY配对延迟至晚偶线期－早粗线期，在早粗线期阶段，配对长度占Y轴全长的30％－50％，到中粗线期配对区开始缩短，在晚粗线期－早双线期解联会，不配对片段常常撕裂成多股，在XY配对Ⅲ型精母细胞中，可见到X与Y长臂远端联合现象（称为次级联合），还对XY配对同源性问题作了进一步的讨论。     

小鼠精母细胞联会复合体RNA组分的电镜研究

邢苗副教授、景德章工程师、郝水教授在《遗传学报》1991年18卷第2期上,发表了题为《小鼠精母细胞联会复合体 RNA 组分的电镜研究》的学术论文.此文内容主要是说明联会复合体(Aynaptonemal complex.sc)被发现以来.大量研究结果表明,真核生物的 sc 结构基本相同,即都由侧生组分、中央组分和 L-C 纤维组成,但是不同种生物 SC 的结构细节可能有一些差异。关于 sc 化学成分的研究报道指出,sc 主要由蛋白质构成.这些蛋白质和核基质有关,其中一些组分是减数分裂前期核所特有的。另外,有些研究工作表明 sc 中存     

荞麦属植物RLKs基因序列分析与亲缘关系研究

从8个荞麦野生种中选取23份荞麦种质资源提取DNA,并根据类蛋白激酶基因(RLKs unigene)序列设计特征引物,进行PCR扩增,对获得的扩增片段进行基因测序与序列分析。结果发现:23份荞麦种质间RLKs基因片段的多态位点数占21.53%,11份野苦荞间RLKs基因片段多态位点数占3.42%,4份野甜荞间多态位点数占1.66%,说明荞麦属植物种内RLKs基因序列高度保守;对扩增序列进行遗传距离分析发现,左贡野甜荞与野甜荞种间遗传距离最小,野甜荞与金荞麦种间遗传距离最大;聚类分析发现,野甜荞与左贡野荞亲缘关系近,与毛野荞和大野荞次之,野苦荞与金荞麦、硬枝野荞和细柄野荞亲缘关系较近。     

杉木EST-SSR与基因组SSR引物开发

利用已经公布的杉木444条EST序列和未公布的杉木基因组文库中1 142条基因序列,进行引物开发效率的比较。去冗余后,利用MISA 搜索SSR 位点,分别得到109个和39个含有SSR的 位点。杉木EST序列中SSR分布密度为964.58个/Mbp,基因组中平均每Mbp出现1 037.24个SSR。在两个独立来源的数据库序列中,六核苷酸重复均为最多的重复类型,且AT-rich的重复类型占较大比例。AGC/CTG是杉木EST序列和基因组库中最多的三碱基重复,通过Primer 3.0分别设计出SSR引物95对和37对。为考察设计引物在杉木不同种源(群体)中的有效性,取12个种源(个体)的优良个体, 利用随机抽取的10个EST-SSR和8个gSSR(基因组SSR)进行引物筛选,结果表明:EST-SSR和gSSR各有4对引物在12个种源(个体)中表现出明显的多态性,多态率分别为40%和50%。8对多态性的SSR引物共扩增出 25 个多态性等位位点,平均每个引物产生 3.125 个多态性等位位点,平均有效的等位位点为2.399 5,PIC平均值为0.519 1; Hot平均为0.307 4。其中gSSR标记在检测群体间存在较大的分化,4个gSSR比4个EST-SSR扩增出更多的等位位点数、平均等位位点数,以及更大的PIC值。     

中国南部沿海条纹斑竹鲨遗传多样性研究

采用随机引物扩增多态性DNA(RAPD)技术分析了中国南部沿海闽东(MD)、闽南(MN)、粤西(YX)3个条纹斑竹鲨地理群体遗传多样性和遗传结构.结果表明,34个随机引物在这3个群体中共检测出316个位点,各群体检测出的位点数分别为308、308、303,其中多态位点数分别为49、52、42,多态位点比例分别为15.90%、16.88%、13.86%.3个群体的Shannon多样性指数分别为0.099 8、0.105 5、0.093 6;表明条纹斑竹鲨群体的遗传多样性水平较低.遗传距离和UPGMA聚类分析结果显示条纹斑竹鲨的基因交流模式属于沿海岸线的距离隔离模式,遗传差异大小与地理距离远近相关.进行分子方差分析(AMOVA)得到遗传变异固定指数(FST=0.044 04,p＜0.05),显示大部分变异(95.60%)发生在群体内部,群体间变异较小(4.40%).     

用45个SNP位点组合对国家啮齿类实验动物种子中心3个封闭群小鼠群体的遗传状况分析

摘要：目的 利用单核苷酸多态性位点对国家啮齿类实验动物种子中心3个封闭群小鼠群体进行群体遗传结构分析。方法 选取文献中45个SNP位点,采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术对来自国家啮齿类实验动物种子中心北京和上海分中心的ICR各1个群体,上海分中心的1个KM封闭群小鼠样本进行等位基因分型,分析群体遗传结构,并进行群体间遗传差异分析。结果 3个封闭群小鼠有效等位基因数(Ne)、观察杂合度(Ho)、期望杂合度(He)、平均杂合度(Ha)、多态信息含量(PIC)、香隆信息指数等遗传参数各不相同。同一群体的结果与微卫星DNA和生化位点的结果相比,SNP检测的参数值较低。但将3个群体中单态的SNP位点去除后参数值有所上升,尤其香隆指数值与STR检测结果接近。结论 所选SNP位点可用于封闭群小鼠遗传质量检测,所检测的3个群体遗传多样性用杂合度评价为SKM >BICR >SICR。     

联会复合体蛋白SYCP2 C-末端的表达、结晶及晶体初步分析

联会复合体蛋白2(SYCP2)作为减数分裂过程中表达的特异性蛋白,是联会复合体轴向组分之一.许多研究表明SYCP2对联会复合体正确组装/去组装可能起着重要作用,尤其是C末端,但具体机制尚不清楚.对鼠源的SYCP2-CTR进行了表达、纯化并用坐滴气相扩散法进行了结晶和优化.在日本PEK收集了1套分辨率为0.4 nm的数据.晶体的空间群为C2,晶胞参数a=16.325 1,b=7.426,7 c=14.823 nm;α=γ=90?,β=119.464?.1个不对称单位4个分子,其溶剂量约为46%.     

洞庭青鲫和洞庭青鲫(♀)×兴国红鲤()杂交F_1代的RAPD分析

以鱼的尾鳍为材料,采用苯酚—氯仿法提取鱼的基因组DNA.对提取的结果进行紫外分光光度、琼脂糖凝胶电泳方法的鉴定,筛选出浓度、纯度好的DNA样品进行进一步的RAPD扩增.采用上海生化工程有限公司的80个引物对洞庭青鲫和洞庭青鲫(♀)×兴国红鲤(♂)杂交F1代(简称“杂交鱼”)进行RAPD分析,筛选出9个引物对洞庭青鲫和杂交鱼进行了遗传多样性分析,这9个引物共检出洞庭青鲫89个位点、杂交鱼82个位点.其中多态性位点数:洞庭青鲫76个,杂交鱼71个分别占其总位点数的85.39%、86.58%.据RAPDdataanalyzer1.3v.exe数据分析程序计算,洞庭青鲫平均遗传相似度为0.6537;杂交鱼的平均遗传相似度为0.6218;两种群间的为0.5505.上述两项指标的初步分析表明,这两种鱼具有较为丰富的遗传多样性.     

BALB/c小鼠遗传污染对单克隆抗体制备的影响

目的检测BALB/c小鼠遗传污染对单克隆抗体制备实验的影响。加强近交系小鼠的饲养管理和重视实验动物的遗传质量检测。方法使用遗传生化标记方法对购进的两批BALB/c小鼠进行了碱性磷酸酶-1(Akp-1)等13个生化位点的检测。结果注射杂交瘤细胞后不产生腹水,经生化检测发现,购买的第一批BALB/c小鼠,在过氧化氢酶-2(Ce-2)等4个生化位点发现杂合基因,第二批BALB/c小鼠在过氧化氢酶-2(Ce-2)等8个生化位点发现杂合基因。结论本实验说明在实验动物的饲养管理上存在漏洞,上述两批BALB/c小鼠未严格按照国家实验动物管理操作规程操作,必须规范实验动物饲养管理,加强实验动物遗传检测,这是保证动物试验结果准确可靠不可或缺的重要环节。     

联会复合体的研究及其在细胞遗传学中的应用

联会复合体(Synaptonemal Complex)是减数分裂前期染包体配对时,同源染包体之间所形成的一种复合结构。最初是由 Moses,M.J.和 Fawcott D.W.于1956年分别在喇蛄、家鸽、猫及人的初级精母细胞的超薄切片中观察到的,Moses M·J·第一次将这种复合结构定名为联会复合体(SCs)。到目前为止,几乎所有观察过的真核生物如真菌、藻类、裸子植物、单子叶植物、双子叶植物、鞭毛虫纲、甲壳纲、昆虫纲、两栖纲、鸟纲和哺乳动物都观察到过这种结构,至于原核生物是否存住 SC_5,尚未见报导。     

褐家鼠染色体减数分裂联会复合体的研究

以界面铺张－硝酸银和磷钨酸（ＰＴＡ）染色技术，对褐家鼠（Ｒａｔｔｕｓｎｏｒｖｅｇｉｃｕｓ）减数分裂前期精母细胞联会复合体（ＳＣ）进行了显微和亚显微结构的观察．银染和ＰＴＡ染色都清楚地显示出褐家鼠ＳＣ的结构和减数分裂的行为，但ＰＴＡ染色的ＳＣ标本，着丝位区域较为明显．ＳＣｓ核型与有丝分裂染色体核型有较好的一致性．     

Adenovirus oncoproteins inactivate the Mre11-Rad50-NBS1 DNA repair complex

In mammalian cells, a conserved multiprotein complex of Mre11, Rad50 and NBS1 (also known as nibrin and p95) is important for double-strand break repair, meiotic recombination and telomere maintenance. This complex forms nuclear foci and may be a sensor of double-strand breaks. In the absence of the early region E4, the double-stranded DNA genome of adenovirus is joined into concatemers too large to be packaged. We have investigated the cellular proteins involved in this concatemer formation and how they are inactivated by E4 products during a wild-type infection. Here we show that concatemerization requires functional Mre11 and NBS1, and that these proteins are found at foci adjacent to viral replication centres. Infection with wild-type virus results in both reorganization and degradation of members of the Mre11-Rad50-NBS1 complex. These activities are mediated by three viral oncoproteins that prevent concatemerization. This targeting of cellular proteins involved in genomic stability suggests a mechanism for 'hit-and-run' transformation observed for these viral oncoproteins.     

Protection of repetitive DNA borders from self-induced meiotic instability

DNA double strand breaks (DSBs) in repetitive sequences are a potent source of genomic instability, owing to the possibility of non-allelic homologous recombination (NAHR). Repetitive sequences are especially at risk during meiosis, when numerous programmed DSBs are introduced into the genome to initiate meiotic recombination. In the repetitive ribosomal DNA (rDNA) array of the budding yeast Saccharomyces cerevisiae, meiotic DSB formation is prevented in part through Sir2-dependent heterochromatin formation. Here we show that the edges of the rDNA array are exceptionally susceptible to meiotic DSBs, revealing an inherent heterogeneity in the rDNA array. We find that this localized DSB susceptibility necessitates a border-specific protection system consisting of the meiotic ATPase Pch2 and the origin recognition complex subunit Orc1. Upon disruption of these factors, DSB formation and recombination increased specifically in the outermost rDNA repeats, leading to NAHR and rDNA instability. Notably, the Sir2-dependent heterochromatin of the rDNA itself was responsible for the induction of DSBs at the rDNA borders in pch2Δ cells. Thus, although the activity of Sir2 globally prevents meiotic DSBs in the rDNA, it creates a highly permissive environment for DSB formation at the junctions between heterochromatin and euchromatin. Heterochromatinized repetitive DNA arrays are abundant in most eukaryotic genomes. Our data define the borders of such chromatin domains as distinct high-risk regions for meiotic NAHR, the protection of which may be a universal requirement to prevent meiotic genome rearrangements that are associated with genomic diseases and birth defects.     

Microconversion between murine H-2 genes integrated into yeast

Patchwork homology observed between divergent members of polymorphic multigene families is thought to reflect evolution by short-tract gene conversion (nonreciprocal recombination), although this mechanism cannot usually be confirmed in higher organisms. In contrast to meiotic conversions observed in laboratory yeast strains, apparent conversions between polymorphic sequences, such as the class I loci of the major histocompatibility complex (MHC), are short and do not seem to be associated with reciprocal recombination (crossover, exchanges). We have now integrated two nonallelic murine class I genes into yeast to characterize their meiotic recombination. We found no crossovers between the MHC genes, but short-tract 'microconversions' of 1-215 base-pairs were observed in about 6% of all meioses. Strikingly, one of these events was accompanied by a single base-pair mutation. These results underscore both the importance of meiotic gene conversion and sequence heterology in determining conversion patterns between divergent genes.     

Direct growth of Fe3O4-MoO2 hybrid nanofilm anode with enhanced electrochemical performance in neutral aqueous electrolyte

To enhance the electrochemical energy storage performance of supercapacitors(SCs), the current researches are general directed towards the cathode materials. However, the anode materials are relatively less studied. In the present work, Fe_3O_4-MoO_2(FO-MO) hybrid nano thin film directly grown on Ti substrate is investigated, which is used as high-performance anode material for SCs in Li_2SO_4 electrolyte with the comparison to pristine Fe_3O_4 nanorod array. The areal capacitance of FO-MO hybrid electrode was initially found to be 65.0 m F cm~(-2)at 2 m Vs~(-1)and continuously increased to 260.0% after 50 cycles of activation. The capacitance values were considerably comparable or higher than many reported thinfilm iron oxide-based anodes in neutral electrolyte. With the protection of MoO_2 shell, the FO-MO electrode developed in this study also exhibited excellent cyclic stability(increased to 230.8% after 1000cycles). This work presents a promising way to improve the electrochemical performance of iron oxidebased anodes for SCs.     

云南松小孢子母细胞减数分裂的研究

以小孢子材料为对象,全程观察并分析了云南松减数分裂各个时期染色体行为及特征.云南松减数分裂构型为11.72II0 0.24II1 0.04I,配对指数为98.67%,环状二价体的频率和配对指数高于其他裸子植物.染色体交叉平均数目(2.42)和染色体异常分裂现象频率(4%)远低于其他裸子植物.云南松在减数分裂过程中染色体的行为表现出高度保守性,与其高度保守的有丝分裂核型较一致.这也说明云南松所在的松属是松科中较原始的类群.     

Clarifying the mechanics of DNA strand exchange in meiotic recombination

During meiosis, accurate separation of maternal and paternal chromosomes requires that they first be connected to one another through homologous recombination. Meiotic recombination has many intriguing but poorly understood features that distinguish it from recombination in mitotically dividing cells, and several of these features depend on the meiosis-specific DNA strand exchange protein Dmc1 (disrupted meiotic cDNA1). Many questions about this protein have arisen since its discovery more than a decade ago, but recent genetic and biochemical breakthroughs promise to shed light on the unique behaviours and functions of this central player in the remarkable chromosome dynamics of meiosis.     

A dynamin-like protein encoded by the yeast sporulation gene SPO15.

The tightly centromere-linked gene SPO15 is essential for meiotic cell division in the yeast Saccharomyces cerevisiae. Diploid cells without the intact SPO15 gene product are able to complete premeiotic DNA synthesis and genetic recombination, but are unable to traverse the division cycles. Electron microscopy of blocked cells reveals a duplicated but unseparated spindle-pole body. Thus cells are unable to form a bipolar spindle. Sequence analysis of SPO15 DNA reveals an open reading frame that predicts a protein of 704 amino acids. This protein is identical to VPS1, a gene involved in vacuolar protein sorting in yeast which has significant sequence homology (45% overall, 66% over 300 amino acids) to the microtubule bundling-protein, dynamin. The SPO15 gene product expressed in Escherichia coli can be affinity-purified with microtubules. SPO15 encodes a protein that is likely to be involved in a microtubule-dependent process required for the timely separation of spindle-pole bodies in meiosis.