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41.
Chie Tomikawa Takayuki Ohira Yasushi Inoue Takuya Kawamura Akihiko Yamagishi Tsutomu Suzuki Hiroyuki Hori 《FEBS letters》2013
Thermoplasma acidophilum is a thermo-acidophilic archaeon. We purified tRNALeu (UAG) from T. acidophilum using a solid-phase DNA probe method and determined the RNA sequence after determining via nucleoside analysis and m7G-specific aniline cleavage because it has been reported that T. acidophilum tRNA contains m7G, which is generally not found in archaeal tRNAs. RNA sequencing and liquid chromatography–mass spectrometry revealed that the m7G modification exists at a novel position 49. Furthermore, we found several distinct modifications, which have not previously been found in archaeal tRNA, such as 4-thiouridine9, archaeosine13 and 5-carbamoylmethyuridine34. The related tRNA modification enzymes and their genes are discussed. 相似文献
42.
Purified glycerol oxidase from Aspergillus japonicus AT 008 was homogeneous by ultracentrifugation and acrylamide gel electrophoresis. The molecular weight was determined to be 400,000 by sedimentation equilibrium, and the isoelectric point was found to be 4.9 by isoelectric focusing. The enzyme showed spectral characteristics of a heme protein. The reduced form possessed absorption maxima at 557 and 430 nm and the oxidized one at 557, 530, 420, 280, and 238 nm. The heme in the enzyme was identified as protoheme IX (one mol per mol of enzyme protein).Glycerol was the best substrate for the enzyme, and the Km value for glycerol was determined to be 10.4 mm. Dihydroxyacetone was oxidized at 59% of that for glycerol, but glycerol 3-phosphate, dihydroxyacetone phosphate, methanol, and ethanol were not oxidized at all. The enzyme had an optimal pH at 7.0 with glycerol as substrate, and the enzymatic activity increased by treatment in alkaline pH. The enzyme was also activated by addition of several divalent metal ions including Zn2+, Ni2+, and Mg2+. 相似文献
43.
Takayuki Oritani Sachio Kudo Kyohei Yamashita 《Bioscience, biotechnology, and biochemistry》2013,77(3):757-760
Asymmetric hydrolysis of acetate (10) of (±)-t-2,t-4-dimethyl-r-l-cyclohexanol with Bacillus subtilis var. niger gave (?)-(lS,2S,4S)-2,4-dimethyl-l-cyclohexanol (6a) and (+)-(1R,2R,4R)-acetate (10b) with high optical purities. Optically pure (?) and (+)-alcohols (6a and 6b) were prepared via corresponding 3,5-dinitrobenzoates. Oxidation of alcohols (6a and 6b) with chromic acid gave optically pure (?)-(2S,4S) and (+)-(2R,4R)-2,4-dimethyl-l-cyclohexanones (2a and 2b), respectively. 相似文献
44.
Photosensitized oxygenation of dehydro-β-ionylidene-ethanol afforded 1′-hydroxy-4′keto-α-ionylidene-ethanol, which was oxidized with active MnO2 to give 1′-hydroxy-4′-keto-α-ionylidene-acetaldehyde. The Wittig reaction of α-ionylideneacetaldehyde with carbethoxymethylenetriphenylphosphorane or the phosphorane prepared from ethyl γ-bromosenecioate gave ethyl α-ionylidene-crotonate or ethyl α-ionylidenesenecioate. Vitamin A2 acid ethyl ester was converted to the hydroxy-keto-ester by photosensitized oxygenation. About the above synthesized compounds were examined growth inhibitory activities on rice seedlings. 相似文献
45.
Sachio Kudo Takayuki Oritani Kyohei Yamashita 《Bioscience, biotechnology, and biochemistry》2013,77(10):2919-2923
(2R*,4S*,6S*,αS*)- and (2R,4R,6R,αS)-Streptovitacin-C2 (STV-C2) (1a and 1b) were synthesized by an aldol condensation of (2R*,4S*)- or (2R,4R)-2,4-dimethyl-2-trimethylsiloxy-1-cyclohexanone (15a or 15b) with 4-(2-oxoethyl)-2,6-piperidinedione (16), which was followed by desilylation of the products. The stereochemistry of the synthesized STV-C2 isomers (1a and 1b) was elucidated by NMR. STV-C2 isomers (1a and 1b) did not show strong antimicrobial activity against Saccharomyces cerevisiae and Pyricularia oryzae. 相似文献
46.
So called ambreinolal (IV),* a component of ambergris, was first synthesized by CrO3 oxidation of ambreinolol (III)* which was obtained from ambreinolide (II) by reduction with LiAlH4. Ambreinolol (III) was converted to the C17-saturated oxide (VII) in a good yield through the monotosylate (VIII) by treatment with p-toluenesulfonyl chloride in pyridine.Ambrein (I), a major constituent of ambergris, was easily converted to ambrein-tetrahydropyranylether (II), of which thermal decomposition gave back ambrein (I). The tetrahydropyranylether (II) was oxidized to ambreinolal-tetrahydropyranylether (V) in two steps. Ambreinolal-tetrahydropyranylether (V) was synthesized from ambreinolol (VII) in four steps and converted to the C17-unsaturated oxide (VI) on heating. 相似文献
47.
Shunya Takahashi Takayuki Oritani Kyohei Yamashita 《Bioscience, biotechnology, and biochemistry》2013,77(10):2711-2718
The total synthesis of ( + )-methyI phaseate (2b) and its epimer (25) is described. The known β- ketoester (8), which was prepared from ( — )-/f-pinene (4), was converted to a key intermediate (5) via a 1, 4-dioxoester (7). The reaction of 5 with a lithium reagent of the acetylene TBDMS ether (6) in THF-HMPA at — 70°C afforded the desired acetylene alcohol (17) and its epimer (18) in high yields. 17 was transformed into ( + )-methyl phaseate (2b). From this synthetic work, the absolute configuration of natural ( — )-phaseic acid (2a) was confirmed. 相似文献
48.
Takayuki Aoyama Yasukazu Nakakita Masahira Nakagawa Heiichi Sakai 《Bioscience, biotechnology, and biochemistry》2013,77(9):2369-2371
Asymmetric hydrolysis of (dl)-1-acyloxy-2-halo-1-phenylethanes by lipoprotein lipase Amano P from Pseudomonas fluorescens and the lipase from Chromobacterium viscosum afforded the optically active (R) residual substrates and (S)-2-halo-1-hydroxy-1-phenylethanes in 100% enantiomeric excess (e.e.). The length of acyl residues from acetyl to octanoyl in the substrates did not influence the enantioselectivity.Both enantiomers of optically active styrene oxides were synthesized from the enzymatic products. 相似文献
49.
Phyu Phyu Khine Zar Satoshi Yano Kozue Sakao Fumio Hashimoto Takayuki Nakano Makoto Fujii 《Bioscience, biotechnology, and biochemistry》2013,77(10):1731-1737
Fresh loquat leaves have been used as folk health herb in Asian countries for long time, although the evidence supporting their functions is still minimal. This study aimed to clarify the chemopreventive effect of loquat tea extract (LTE) by investigating the inhibition on proliferation, and underlying mechanisms in human promyelocytic leukemia cells (HL-60). LTE inhibited proliferation of HL-60 in a dose-dependent manner. Molecular data showed that the isolated fraction of LTE induced apoptosis of HL-60 as characterized by DNA fragmentation; activation of caspase-3, -8, and -9; and inactivation of poly(ADP)ribose polymerase. Moreover, LTE fraction increased the ratio of pro-apoptotic Bcl-2-associated X protein (Bax)/anti-apoptotic myeloid cell leukemia 1 (Mcl-1) that caused mitochondrial membrane potential loss and cytochrome c released to cytosol. Thus, our data indicate that LTE might induce apoptosis in HL-60 cells through a mitochondrial dysfunction pathway. These findings enhance our understanding for chemopreventive function of loquat tea. 相似文献
50.
Saki Inamine Shoko Onaga Takayuki Ohnuma Tamo Fukamizo 《Bioscience, biotechnology, and biochemistry》2013,77(8):1296-1304
Chitinase-A (EaChiA), molecular mass 36 kDa, was purified from the vegetative stems of a horsetail (Equisetum arvense) using a series of column chromatography. The N-terminal amino acid sequence of EaChiA was similar to the lysin motif (LysM). A cDNA encoding EaChiA was cloned by rapid amplification of cDNA ends and polymerase chain reaction. It consisted of 1320 nucleotides and encoded an open reading frame of 361 amino acid residues. The deduced amino acid sequence indicated that EaChiA is composed of a N-terminal LysM domain and a C-terminal plant class IIIb chitinase catalytic domain, belonging to the glycoside hydrolase family 18, linked by proline-rich regions. EaChiA has strong chitin-binding activity, however, no antifungal activity. This is the first report of a chitinase from Equisetopsida, a class of fern plants, and the second report of a LysM-containing chitinase from a plant. 相似文献