H2株甲肝减毒活疫苗K7的核苷酸全序列分析

应用ＲＴ－ＰＣＲ获取Ｈ２株甲肝减毒活疫苗（Ｋ７）的ｃＤＮＡ片段，经末端终止测序ＰＣＲ试剂盒和全自动测序仪（ＡＢＩ３７７）作序列测定，用Ｍａｘｔｒｉｇｅｎｅ软件进行计算机分析，Ｋ７疫苗病毒的核苷酸全长含７４４３个碱基．Ｋ７对比其亲代Ｈ２株，减毒的ＨＭ１７５株以及ＨＭ１７５野毒株，同源性分别为９９．７５％，９９．９５％和９９．６１％；彼此间在Ｐ１和Ｐ２连接区１６８个碱基的同源性为９９．４％～１００％，均为ⅠＢ基因亚型．前三者在５’非编码区均有１３１～１３４位和２０３位５个碱基缺失，且结构蛋白基因区序列完全一致．本文用分子病毒学方法证实了Ｋ７疫苗的优异纯毒水平，也为开展甲型肝炎分子流行病学工作提供了基础资料     

关于带m-增生算子扰动的非线性方程具误差的强收敛迭代序列

研究了在任意Banach空间,形如f∈Tx+Ax+Cx的非线性方程的解的逼近问题.其中T:E→2E为m-增生的,A:E→E是增生的,C:E→E是一个满足适当条件的非线性映射.构造了一个新的迭代序列,求得这一迭代序列的极限即为该方程的逼近解,从而推广了有关文献中的某些结果.     

Thymidine kinase gene mutation leads to reduced virulence of pseudorabies virus

To explore correlation between the tk gene structure of pseudorabies virus (PRV) and its virulence, to study the effect of the gene mutation on PRV biological properties, and to investigate mechinism of reduced virulence, thymidine kinase (TK)-deficient mutant of pseudorabies virus strain Hubei (PRV HB) was isolated by selection for resistance to 5-bromodeoxyuridine. The tk genes of PRV HB and its TK^― mutant were cloned and sequenced. 1587 base pairs of the tk gene and flanking regions of wild-type (wt) virus were sequenced, which included an open reading frame (ORF) of 1098 bp encoding a protein of 366 amino acids. The ORF contained two 137-bp repeated sequences, which were connected by an adenosine. 1458 bp of the tk and flanking regions of TK^― mutant were sequenced. Analysis of the tk gene sequence of TK^― mutant indicated that one of 137 bp repeated sequence and the connecting adenosine in the tk gene of the wt virus was deleted and a repeated sequence of 8 nucleotides (GCGCGCC) was inserted. All other nucleotides of TK^―mutant were identical to that of wt virus. Deletion and insertion of the nucleotide sequence resulted in a frameshift and a premature chain termination, and the resultant TK protein was not active. Analysis of the amino acid sequence revealed that TK protein of PRV HB contained the conserved consensus sequence of herpesviral TKs and an additional conserved-DHR-motif. The results of this work also indicated that TK^― mutant was genetically stable. Compared to PRV HB, virulence of TK^― mutant was greatly decreased. Mice vaccinated with TK^― mutant were completely protected against a lethal challenge with virulent PRV (HB).     

Analysis of the characteristic sequence of intein and revision of its motifs

Since the first intein (Sce VMA) was found inSaccharomydes cerevisiae ATPases gene in 1990, more and more inteins were identified. It is necessary to analyze the new inteins to understand the sequence charateristics of inteins. By searching protein and nucleic acid database systematically, 101 inteins were found, of which 69 inteins contain homing endonuclease motifs. We only analyze the 69 inteins since most inteins are the classic inteins with homing endonuclease motifs. We found that the distribution of these inteins is particular among species and protein. By multiple sequence alignment, some new sequence characteristics were found and the motifs described previously were revised.     

毛冠鹿p16^INK4基因第二外显子序列分析

采用PCR扩增技术首次克隆毛冠鹿p16^INK4基因第二外显子，DNA杂交和序列分析发现，在307个碱基的第二外显子中仅有5个碱基的差异，同源性达98．4％，p16^INK4基因的第二外显子是高度保守的区域，在其功能中起重要作用。     

关于John Beebee的一个问题

回答了John Beebee关于不相交同余覆盖的一个问题。     

一种OFDM系统载波频率同步的改进方法

载波频率同步是OFDM系统的关键技术.对Schmid方法进行了改进,提出了利用PN序列迭代的载波频率同步方法,即将频偏估计分成粗估计和精估计两个步骤,在复杂度相同的情况下提高了频偏估计的精度和范围.     

一个有较大倒数和的B2(i≠j)序列

如果所有的两项和ai aj都不同,就称正整数序列a1＜a2＜…是一个B2-序列.Mian-Chwla序列是用贪婪算法得到的B2-序列,它的倒数和S*曾被猜测为所有B2-序列倒数和的最大值.根据是否允许i=j,相应有两个问题.在允许i=j时,张振祥证明了S*＜2.1596及M＞2.1597,从而推翻了这个猜测.本文研究不允许i=j(或简称i≠j)的情形.我们给出一个有较大倒数和的B2(i≠j)序列:它的前9项由贪婪算法得到,第10项是54,从第11项起继续用贪婪算法.我们新序列的前200项倒数和大于Main-Chowla(i≠j)序列的倒数和.     

沉积地球化学在层序地层分析中的应用

对于层序地层学研究来说最基本的、也是最关键的问题是层序的识别,而层序的识别包括两个方面的内容,一是层序界面的识别,二是层序内体系域构成的识别.层序界面和层序内体系域的识别除宏观的沉积记录分析方法外,还可通过微观的沉积地球化学分析资料来识别.研究表明,在层序界面的形成过程中,伴随着风化作用的进行,在层序界面上的Fe元素以高价Fe的氧化物形式出现;Al含量高,主要为Al的氧化物;K的含量大于Na元素的含量;Th/U比值很大.体系域与REE和微量元素、常量元素含量密切相关,LST(或SMST)期REE含量最低,TST期REE含量逐渐增高至最大,海泛期达到最高, HST期又逐渐下降.LST期,微量元素含量最低,TST期微量元素含量逐渐增高直至最高,HST期微量元素含量又逐渐下降.