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971.
972.
The protein that binds to DNA base J in trypanosomatids has features of a thymidine hydroxylase
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Yu Z Genest PA ter Riet B Sweeney K DiPaolo C Kieft R Christodoulou E Perrakis A Simmons JM Hausinger RP van Luenen HG Rigden DJ Sabatini R Borst P 《Nucleic acids research》2007,35(7):2107-2115
Trypanosomatids contain an unusual DNA base J (beta-d-glucosylhydroxymethyluracil), which replaces a fraction of thymine in telomeric and other DNA repeats. To determine the function of base J, we have searched for enzymes that catalyze J biosynthesis. We present evidence that a protein that binds to J in DNA, the J-binding protein 1 (JBP1), may also catalyze the first step in J biosynthesis, the conversion of thymine in DNA into hydroxymethyluracil. We show that JBP1 belongs to the family of Fe(2+) and 2-oxoglutarate-dependent dioxygenases and that replacement of conserved residues putatively involved in Fe(2+) and 2-oxoglutarate-binding inactivates the ability of JBP1 to contribute to J synthesis without affecting its ability to bind to J-DNA. We propose that JBP1 is a thymidine hydroxylase responsible for the local amplification of J inserted by JBP2, another putative thymidine hydroxylase. 相似文献
973.
为了获得能够携带较大外源基因的犬2型腺病毒E3区缺失性载体,以犬2型腺病毒全基因组质粒pPolyⅡ-CAV-2及E3区重组质粒pVAX-E3为基础,缺失1381bp的E3区片段(92.6%的E3区全序列),插入Linker-NF(内含NotⅠ、ClaⅠ、FseⅠ多克隆位点),获得重组载体质粒pPolyⅡ-CAV-2-ΔE3(NF)(31.9kb)。以AscⅠ和PmeⅠ双酶切,游离重组基因组,在脂质体LipofectamineTM 2000介导下,转染MDCK细胞系,获得了E3区缺失的重组病毒CAV-2-ΔE3(NF)。通过病毒的形态学观察,血凝性、生长特性、感染性实验证明,该重组病毒与母源病毒没有差异。重组病毒CAV-2-ΔE3(NF)可以作为载体表达外源基因,其外源基因插入片段不小于3.3kb。 相似文献
974.
Species in the genus Oryza (Poaceae) contain 10 genomic types and are distributed in pan-tropics of the world. To explore phylogenetic relationships
of Oryza species having the AA-genome, DNA sequences of the chloroplast trnL intron and trnL-trnF spacer, mitochondrial nad1 intron 2, and nuclear internal transcribed spacer were analyzed, based on materials from 6 cultivated (O. sativa and O. glaberrima) and 13 wild accessions, in addition to a CC-genome species (O. officinalis) that was used as an outgroup. Analyses of the combined sequence data set from different sources provide a much better resolution
of the AA-genome species than the individual data set, indicating the limitation of a single gene in phylogenetic reconstruction.
The phylogeny based on the combined data set demonstrated an apparent grouping of the AA-genome Oryza species that was well associated with their geographic origin, although the Australian O. meridionalis showed its affinity with the African species. The geographic pattern of the phylogenetic relationship was probably attributed
to the frequent genetic exchange and introgression among the AA-genome species from the same continents. In addition, Asian
cultivated rice O. sativa showed its close relation to O. rufipogon and O. nivara, whereas African cultivated rice O. glaberrima was closely linked to O. barthii and O. longistaminata, indicating the independent domestication of the two cultivated species in different geographic locations. 相似文献
975.
转双价抗虫基因毛白杨无性系85号抗虫性研究 总被引:2,自引:0,他引:2
以优化的毛白杨无性系85号最适遗传转化体系为基础,通过农杆菌介导法将Bt(CryⅠAc)和API双价抗虫基因导入毛白杨无性系85号基因组.在高浓度卡那霉素的培养基上诱导不定芽和根,初步选择到200株转化植株,PCR检测显示,66株呈阳性反应.Southern杂交和ELISA检测进一步证明,Bt(CryⅠAc)和API双价抗虫基因已整合到毛白杨无性系85号基因组中,并得到了表达.对转化植株用舞毒蛾幼虫进行饲虫试验,结果显示昆虫幼虫的死亡率高达60.0%~77.8%,且存活幼虫的生长发育也受到了明显抑制.研究结果为杨树抗虫育种提供了新的种质资源. 相似文献
976.
苦杏仁精油的熏蒸杀虫活性研究 总被引:2,自引:0,他引:2
采用三角瓶密闭熏蒸法测定了苦杏仁精油对家蝇、白纹伊蚊、粘虫以及玉米象的熏蒸杀虫活性,结果显示:苦杏仁精油对各试虫均有较强的熏蒸杀虫活性,其中含HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.09、0.63、4.63、12.03μL/L;除去HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.53、0.52、4.08、23.46μL/L;熏蒸的时间效应试验结果表明,含有HCN的苦杏仁精油和不含HCN的苦杏仁精油对供试试虫的熏杀速度均较快,其中白纹伊蚊的反应最快,其次为家蝇、粘虫、玉米象.除玉米象外苦杏仁精油中所含的微量HCN对试虫的熏蒸活性影响不大,且2种处理的精油对同种试虫的致死中时差别范围不超过10 min.实验结果表明,苦杏仁精油可作为新型的杀虫活性物质,为苦杏仁精油作为植物源杀虫剂提供了依据. 相似文献
977.
978.
Stiff CM Zhong M Sarver RW Gao H Ho AM Sweeney MT Zurenko GE Romero DL 《Bioorganic & medicinal chemistry letters》2007,17(19):5479-5482
Previously we reported the discovery and initial optimization of a novel anthranilic acid derived class of antibacterial agents which suffered from extensive protein binding. This report describes efforts directed toward understanding the relationship of the acidity of the carboxylic acid with the extent of protein binding. The pK(a) of the acid was modified via the synthesis of a number of anthranilic acid analogs which vary the aromatic ring substituent at the 4-position. The pK(a) and HSA binding constants have been determined for each of the analogs. Our results indicate a correlation between pK(a) and HSA K(d). The physical properties and antibacterial activities will be discussed as well as how these results help address the protein binding issue with this series of compounds. 相似文献
979.
Xiang MA Rybczynski PJ Patel M Chen RH McComsey DF Zhang HC Gunnet JW Look R Wang Y Minor LK Zhong HM Villani FJ Demarest KT Damiano BP Maryanoff BE 《Bioorganic & medicinal chemistry letters》2007,17(23):6623-6628
We have continued to explore spirobenzazepines as vasopressin receptor antagonists to follow up on RWJ-339489 (2), which had advanced into preclinical development. Further structural modifications were pursued to find a suitable backup compound for human clinical studies. Thus, we identified carboxylic acid derivative 3 (RWJ-676070; JNJ-17158063) as a potent, balanced vasopressin V(1a)/V(2) receptor antagonist with favorable properties for clinical development. Compound 3 is currently undergoing human clinical investigation. 相似文献
980.
Zhong X Wei HL Liu WS Wang DQ Wang X 《Bioorganic & medicinal chemistry letters》2007,17(13):3774-3777
Mononuclear complexes of Cu(II), Ni(II), and Mn(II) with a new Schiff base ligand derived from indoline-2,3-dione and 2-hydroxybenzohydrazide, [Cu(II)(L)(2)], [Ni(II)(L)(2)], and [Mn(II)L.(AcO).2C(2)H(5)OH] [HL=(Z)-2-hydroxy-N'-(2-oxoindolin-3-ylidene)benzohydrazide], have been prepared. The complexes have been structurally characterized by X-ray crystallography. Among the three complexes, the Cu(II) complex had the novel highest antitumor activity. 相似文献