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排序方式: 共有564条查询结果,搜索用时 15 毫秒
1.
Cloning and sequencing of Schizosaccharomyces pombe DNA topoisomerase I gene, and effect of gene disruption. 总被引:18,自引:7,他引:11
We cloned the structural gene topl+ for Schizosaccharomyces pombe DNA topoisomerase I (topo I) by hybridization. An eight-fold increase of topo I relaxing activity was obtained in S. pombe cells transformed with multicopy plasmid with topl+ insert. Nucleotide sequence determination showed a hypothetical coding frame interrupted by two short introns, encoding a 812 residue polypeptide (M.W. 94,000), 43 residues longer than and 47% homologous to Saccharomyces cerevisiae topo I. We show that the topl (null) strain made by gene disruption is viable, although its generation time is 20% longer than that of wild type. The topl locus is mapped in the long arm of chromosome II, using the Leu+ marker integrated with the cloned topl+ sequence. We constructed a double mutant topl (null) top2 (ts) and found its defective phenotype similar to that of previously obtained topl (heat sensitive) top2 (ts). The other double mutant topl (null) top2 (cs), however, was lethal. Our results suggest that topl+ gene of S. pombe is dispensable only if topo II activity is abundant. 相似文献
2.
Noriaki Murakami Yoshiyuki Tanaka Kunio Takishima Yuzo Minobe Makoto Matsuoka Sei-Ichiro Kiyota Shin-ichi Hatanaka Katsuhiro Sakano 《Journal of plant research》1990,103(4):419-434
We isolated the small subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO SSu) from a fern,Asplenium cataractarum and determined its 34 N-terminal amino acid sequence. We obtained a cDNA clone that contains the entire coding region of
the SSu from the same fern species, using synthetic oligonucleotide probes derived from the above amino acid sequence. It
contains a 525 bp open reading frame capable of coding for a polypeptide with 174 amino acids, 31 bp 5′-and 206 bp 3′-noncoding
regions. It was also elucidated that the precursor to the SSu contains a transit peptide of 53 amino acid residues and a mature
protein of 121 residues. We compared the deduced amino acid sequence of the fern SSu with those of 11 other vascular plant
species (including gymnosperms, monocots and dicots). As low as 55% homology was observed between those of a fern and seed
plants. Constancy of the amino acid substitution rate in RuBisCO SSu was supported by our relative rate test. Amino acid substitution
rate per year per site for RuBisCO SSu was calculated to be 0.81×10−9 assuming that the separation between pteridophytes and seed plants arose 380 million years ago. 相似文献
3.
Tazawa Masashi; Kurosawa Sachiko; Amino Shin-ichi; Tominaga Yoshito; Sakano Katsuhiro; Matsumoto Tomotaka 《Plant & cell physiology》1991,32(2):253-260
Rotational cytoplasmic streaming in leaves of Egeria densa wasinduced by light as well as by L-histidine (L-His). During bothtreatement with light and with L-His chloroplasts on the periclinalface were dislodged and moved to the anticlinal face where rotationalcytoplasmic streaming occurred. The effective concentrationof L-His was about 0.01 mM and the effect was almost saturatedat 0.1 mM. A derivative of L-His, 3-methyl-L-histidine, wasslightly less effective than L-His. By contrast, 1-methyl-L-histidinewas almost ineffective for induction of streaming, not onlyin Egeria but also in Vallisneria. Our resutlts are in markedcontrast to Fitting's result (1936) that 1-M-L-His is more effectivethan L-His. In Egeria, 1-methyl-L-His counteracted the stimulativeeffect of L-His. 1-Methyl-L-His penetrated into leaf cells ofEgeria to the same extent as 3-methyl-L-His and to a greaterextent than L-His. This observation excludes the possibilitythat the impermeability of leaves to 1-M-L-His might be responsiblefor its ineffectiveness. 1-M-L-His did not interfere with photodinesis.Differences in the mechanism of induction of rotational streamingby L-His and by light are discussed.
4 Present address: Fukui Institute of Technology, Gakuen, Fukui,910 Japan (Received July 16, 1990; Accepted December 20, 1990) 相似文献
4.
The fission yeast cut1+ gene regulates spindle pole body duplication and has homology to the budding yeast ESP1 gene 总被引:20,自引:0,他引:20
Mutations in the fission yeast cut1+, cut2+, and cut10+ genes uncouple normally coordinated mitotic events and deregulate, rather than arrest, mitosis. DNA synthesis continues, making polyploid nuclei with several spindles. Multiple, aberrant spindle pole bodies (SPBs) are produced in cut1 mutant cells. The cut1+ and cut2+ genes are cloned by transformation. High gene dosage of cut1+ also complements cut2 and cut10 mutants. The cut2+ gene, however, complements only cut2. The 210 kd cut1+ gene product contains putative ATP binding and helical coil regions followed by a COOH-terminal domain homologous to the S. cerevisiae gene ESP1. Mutations in the ESP1 gene also result in many SPBs. The cut1+ product is shown by anti-cut1 antibody to be a rare component of the insoluble nuclear fraction. It may play a key role in coupling chromosome disjunction with other cell cycle events and is potentially a component, regulator, or motor for the SPB and/or kinetochores. 相似文献
5.
Corrigendum
Upstream regulatory sequences from two -conglycinin genes 相似文献6.
Toshiro Matsui Miho Imamura Hiromi Oka Katsuhiro Osajima Ko-Ichi Kimoto Terukazu Kawasaki Kiyoshi Matsumoto 《Journal of peptide science》2004,10(9):535-545
The distribution of an antihypertensive dipeptide, Val-Tyr (VY), in the tissues of spontaneously hypertensive rats (SHR) was investigated in this study. A single oral administration of VY (10 mg/kg) to 18-week-old SHR resulted in a prolonged reduction of systolic blood pressure (SBP) up to 9 h (SBP0h 198.0+/-3.6 mmHg; SBP9h 154.6+/-3.5 mmHg). As a result of VY determination, a roughly 10-fold higher increment of plasma VY level was observed at 1 h than that at 0 h, whereas thereafter the level declined rapidly. In tissues, VY was widely accumulated in the kidney, lung, heart, mesenteric artery and abdominal aorta with the area under the curve over 9 h of more than 40 pmol h/g tissue; of these a higher VY level was observed in the kidney and lung. In addition, a mean resident time (MRT) for each tissue (>5 h except for liver) revealed that VY preferably accumulated in the tissues rather than in the plasma (MRT 3.8 h). Significant reductions of tissue angiotensin I-converting enzyme activity and angiotensin II level were found in the abdominal aorta as well as in the kidney, suggesting that these organs could be a target site associated with the antihypertensive action of VY. 相似文献
7.
Katsuhiro Kawashiro Hideki Sugahara Sigeru Sugiyama Hiromu Hayashi 《Biotechnology letters》1995,17(11):1161-1166
Summary The -chymotrypsin-catalyzed transesterification between N-trifluoroacetyl-DL-phenylalanine trifluoroethyl ester and 1-propanol was carried out in a variety of organic solvents. The addition of small quantities of water enhanced both the rate of reaction and enantioselectivity. A high enantioselectivity was achieved in ethyl acetate (E = 120), diethyl ether (86), or acetonitrile (60). The competing hydrolysis became significant at water content higher than 0.5% (w/w). 相似文献
8.
Cell walls of 4-day old rice seedlings were extracted successivelywith ammonium oxalate-oxalic acid, 4% KOH and 24% KOH. A rß-D-glucanpreparation and a xyloglucan preparation were isolated fromthe 4% KOH extract and 24% KOH extract, respectively. Methylationanalysis and enzymic degradation studies of the polysaccharidesshowed that the former was built up predominantly of repeating-oligosaccharideunits of 3-O-rß-cellobiosyl-D-glucose and 3-O-rß-cellotriosyl-D-glucosein a molar ratio of 2.6 : 1.0, and the latter was of repeating-oligosaccharideunits of -D-xylosyl-(16)-rß-D-glucosyl-(14)-[-D-xylosyl-(16)]-rß-D-glucosyl-(14)-D-glucose,-D-xylosyl-(16)-rß-D-glucosyl-(14)-D-glucose and cellobiose.
1 Present address: Department of Botany, Iowa State University,Ames, Iowa 50011, U.S.A. (Received August 29, 1981; Accepted January 12, 1982) 相似文献
9.
Sei-itsu Murota Midori Abe Katsuhiro Otsuka Wen-Chang Chang 《Prostaglandins & other lipid mediators》1977,13(4):711-717
Early effects of various prostaglandins on the production of hexosamine-containing substances by cultured fibroblasts, which were derived from a rat carrageenin granuloma, were studied. At the stationary phase, the cells were exposed for 6 h to one of the prostaglandin A1 (PGA1), A2, B1, B2, D2, F1α, F2α, E1, E2 or arachidonic acid in various concentrations ranging from 0.01 to 10 μg/ml for all the stimuli and from 10 pg to 10 μg/ml for PGF2α. The activity of the cells in incorporating 3H-glucosamine into hexosamine-containing substances (acidic) glycosaminoglycans and glycoproteins) during this period was compared with that of control cells. All the stimuli tested showed more or less stimulative effect on the synthesis of hexosamine-containing substances at their specific concentrations. PGF2α was found to be the most potent stimulant and its stimulative effect was found significant even at the low concentration of 100 pg/ml. PGD2, F1α and E2 were the next potent stimuli. Their optimum dose were around 1 μg/ml but they still had significant stimulation at the concentration of 0.01 μg/ml. Effect of PGE2 was rather mild. Stimulation by PGA1, A2, B1 and B2 or arachidonic acid was seen at high dose, and its seemed to be non-specific. The results suggested that these prostaglandins such as PGF2α, D2, F1α and E2 play some important role on regulating the production of intercellular ground substances. 相似文献
10.
Kazuhiro Watanabe Kaori Takanashi Susumu Imaoka Yoshihiko Funae Sumie Kawano Katsuhiro Inoue Tetsuya Kamataki Hidetoshi Takagi Itsuo Yoshizawa 《The Journal of steroid biochemistry and molecular biology》1991,38(6):737-743
For identification of microsomal cytochrome P-450 (P-450) enzymes which catalyze 2- or 4-hydroxylations of estrogens in the rat liver, estradiol (E2) and estradiol 17-sulfate (E2-17-S) were selected as the substrates and incubated with various kinds of purified P-450 enzymes: PB-1, PB-2, PB-4 and PB-5 obtained from phenobarbital-treated male rats (Sprague-Dawley); MC-1 and MC-5 from 3-methylcholanthrene-treated male rats; and UT-1, UT-2, UT-4 and UT-5 from untreated animals. The reactions were carried out under the P-450-reconstructed system, and the resulting products were determined by HPLC using electrochemical detection. All the enzymes tested were shown to have varying degrees of catalytic activities for 2-hydroxylation of the two substrates; UT-1 and UT-2 had the highest activity. Of the induced P-450 enzymes, PB-2 and MC-1 showed fairly high catalytic activity for 4-hydroxylation of E2. The P-450 enzymes obtained from the untreated male rats, especially UT-4, showed the highest catalytic activity for 4-hydroxylation of the two substrates. From these results and also from kinetic experiments, the P-450 enzymes which catalyze 2- and 4-hydroxylations of estrogen were considered to be different species. A part of E2 was converted to such metabolites as estrone and those having a hydroxyl group at positions 6β, 15 or 16, each production of which was estimated to be catalyzed by single or multiple P-450s. 相似文献