大肠杆菌

Glioma is still one of refractory disease in the neurosurgical field; the development of new primary and adjuvant treatment is vital. Recently, the gene therapy of glioma is developed rapidly and there are many methods about the gene therapy that include: suicide gene therapy, immunologic gene therapy, drug resistangce gene therapy, angiostatin gene therapy and so on. The sucide gene therapy is the most potential approach of antitumer, these nonmammalian genes encode enzyme that convert nontoxic prodrugs into highly toxic metablites. Cells transfected with suicide genes are targeted for specific negative selection, witch can be induced by administrtion of the corresponding produg. Among the enzyme/produg combinations, two of the best characterized system are herpes simplex virus thymidine kinase /ganciclovir and Escherichia coli cytosine deaminase /5-flourocytosine (5-FC). The formor can convert the antiviral nucleoside analogs acyclovir , ganciclovir to their nucleoside monophosphate derivatives, the monophosphate forms are subsequently phosphorylated by endogenus cellular kinases to triphosphates, these molecules are potent inhibitors of DNA synthesis.

近年来脑胶质瘤的基因治疗发展迅速，应运而生的方法有自杀基因、免疫基因、多药耐药基因以及抗血管生成基因等，其中自杀基因被认为是最有前景的基因治疗方法，它又称病毒介导的酶／药物前体疗法，是利用转基因技术将哺乳动物细胞中所不含有的自杀基因转入到哺乳动物肿瘤细胞中，该基因表达的产物可将无毒的药物前体转化为毒性药物，从而选择性杀伤该肿瘤细胞，常用的自杀基因有单纯疱疹病毒-胸苷激酶基因和大肠杆菌胞嘧啶脱氨酶基因，前者催化无毒性抗病毒核苷类似物如丙氧鸟苷、无环鸟苷等成为单磷酸核苷衍生物，然后在内源性细胞激酶作用下转化为具有明显毒性的三磷酸核苷，作为DNA合成链的终止剂和DNA合成酶的抑制剂，干扰细胞DNA的合成；后者编码的胞嘧啶脱氨酶可催化5-氟胞嘧啶（5-FC）脱氨成为5-氟尿嘧啶（5-FU），然后代谢为有毒性的5-氟尿嘧啶-5′三磷酸（5-FUTP）和5-氟-2′脱氧尿嘧啶-5′磷酸（5-FdUTP），5-FUTP通过与UTP竞争性结合而抑制mRNA和tRNA的合成，5-FdUTP则作用于胸苷合成酶，导致TMP衰竭而阻止DNA的合成，最终诱导肿瘤细胞凋亡。

E.coli RNA polymerase can transcribe all the genes of E.coli, but the three eukaryotic RNA polymerases transcribe only specific, nonoverlapping subsets of eukaryotic genes.

eukaryotic genes 大肠杆菌的RNA聚合酶能够转录所有的基因，但真核生物的三种RNA聚合酶各自只能转录特定的、不相重叠的一组基因。

The in vitro and in vivo activity of these specific IgY and their opsonization to phagocytes were estimated.Specific IgY were produced by hens immunized with formaldehyde killed S.aureus or E.

本研究制备了抗奶牛乳腺炎主要致病菌——金黄色葡萄球菌和大肠杆菌特异性卵黄抗体，考察了抗体的体外抑菌活性、对吞噬细胞的吞噬调理作用及对奶牛乳腺炎的治疗作用。

In chapter 6, the recognition of ORF and exon in several representative lower organisms, E. coli, S. cerevisiae and C.

第六章讨论了大肠杆菌、酵母和线虫这几种低等生物中ORF和外显子的识别。

In this study, the structure sequences of Shiga toxin 2B(stx2B) and Shiga toxin 1B(stx1B) were respectively amplified from EHEC O157:H7 by PCR. stx2B-L-stx1B fusion gene was constructed by a 12 bp linker ligating these two fragments. After digested with restriction endonuclease Nco Ⅰ and EcoR Ⅰ, the fusion gene was orientally inserted into expression vector pET28a.

利用PCR方法，从肠出血性大肠杆菌O157：H7的基因组DNA中，分别扩增出Stx1B和Stx2B亚基的结构基因片段，然后再通过PCR将这2个片段连接起来，并定向克隆到表达质粒pET28a的NcoⅠ和EcoRⅠ位点之间，构建了重组表达质粒pMB1。

Objective To overexpress human acidic fibroblast growth factor in Escherichia coli and study the biological activities of recombinant aFGF.

目的：探讨人酸性成纤维细胞生长因子（acidic fibroblast growth factor， aFGF）在大肠杆菌中高效表达的方法及重组人aFGF的生物学活性。

According to the sequence and functional analysis result some ORFs was selected to overexpress in E. coli. Cloning of the endogenous plasmid SLP3 of S.

随后根据测序的结果以及复制区和接合转移功能区鉴定的结果，选择对一些重要的功能蛋白进行在大肠杆菌中的过量表达。

The effects of panD mutation on the production of EPS and extracellular enzymes were also determined.

这一结果表明，Xcc 8004中泛酸合成途径与大肠杆菌存在一定的差异。

The E. coli, Pasteurella and Salmonella media were used to culture the isolated pathogenic bacteria in vitro. After culturing for some time, the growth of enteric pathogen colony on the 3 kinds of media was most obvious.

分别用大肠杆菌培养基、巴氏杆菌培养基和沙门氏菌培养塞对分离出的病原菌进行体外培养试验，培养一段时间后，来自肠道的病原菌在3种培养基上的菌落生长最明显。

Through comparison of 16S rRNA gene sequence of Riemerella anatipestifer serotype 1 to 19 with that of Escherichia coli,Salmonella,Pasteurella and Staphylococci,a pair of specific primers was designed.

根据 GenBank中的鸭疫里默氏杆菌1～19型16S rRNA基因序列，分别与大肠杆菌、沙门氏菌、葡萄球菌、巴氏杆菌的16S rRNA基因序列对比，设计特异性引物，建立了基于鸭疫里默氏杆菌16S rRNA的PCR检测方法。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。