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991.
Hiroyuki Hamazaki Takayuki Abe Hidefumi Yamakawa Tomoyuki Yokota Shiro Shigeta Hiroshi Takaku 《Helvetica chimica acta》2002,85(7):2183-2194
We have demonstrated that a new type of circular dumbbell RNA/DNA chimeric oligonucleotide (CDRDON) with two closed nucleotide or alkyl loop structures (hexa‐ethylene glycol) inhibits influenza virus A replication in MDCK cells. The enzymatic synthesis of circular dumbbell RNA/DNA chimeric oligonucleotides was achieved by enzymatically ligating a self‐complementary phosphorylated oligonucleotide with T4‐RNA ligase. The CDRDON‐Al, with two closed alkyl loop structures, showed higher nuclease resistance, hybridization, and cellular uptake than the anti‐S‐ODN and the CDRDON, with two closed nucleotide hairpin‐loop structures. The circular dumbbell RNA/DNA chimeric oligonucleotide (CDRDON‐Al‐PB2‐as), containing an AUG initiation‐codon sequence as the target of PB2, showed highly inhibitory effects on influenza A virus RNA expression. The limited toxicity of unmodified phosphodiester oligonucleotides and the sequence‐specific binding to target mRNA indicate that circular dumbbell RNA/DNA chimeric phosphodiester oligonucleotides can be used with intact cells, and may prevent viral replication in culture. 相似文献
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Haruo Nishida Fumio Sanda Takeshi Endo Takeshi Nakahara Takayuki Ogata Koshi Kusumoto 《Journal of polymer science. Part A, Polymer chemistry》1999,37(24):4502-4509
The addition reaction of spiro orthoesters (SOEs) with electrophiles accompanying ring-opening isomerization was investigated as a model reaction for polyaddition of bifunctional SOEs with bifunctional electrophiles. Among several electrophiles such as carboxylic acids and carboxylic anhydrides, acid halides showed particularly high reactivities to SOEs. An equimolar reaction of SOEs with acid chlorides took place selectively, leading to the corresponding 1 : 1 adducts. SOEs with seven-membered cyclic ether rings—1,4,6-trioxaspiro[5.6]undecane derivatives—showed higher reactivities than SOEs with six- and five-membered cyclic ether rings. The reaction accompanied zero shrinkage in volume. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4502–4509, 1999 相似文献
1000.
Hiroyuki Asanuma Takanori Ito Takayuki Yoshida Xingguo Liang Makoto Komiyama 《Angewandte Chemie (International ed. in English)》1999,38(16):2393-2395
The duplex-forming activity of an oligonucleotide has been photoregulated by making use of the isomerization of an azobenzene moiety in the side chain. When the azobenzene moiety is isomerized from the trans form to the cis form upon photoirradiation, the melting temperature of the duplex between the oligonucleotide and its complementary counterpart is significantly lowered, and the duplex is largely dissociated into two single-stranded oligonucleotides (shown schematically). 相似文献