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951.
Takashi Yokochi Yoshiko Inoue Guo-zhi Jiang Yutaka Kato Tsuyoshi Sugiyama Makoto Kawai Masako Fukada Kazuko Takahashi 《Microbiology and immunology》1994,38(11):901-903
A polymyxin B (PXB)-resistant mutant of Klebsiella pneumoniae O3 was isolated. Lipopolysaccharide (LPS) extracted from the PXB-resistant isolate bound little PXB, although LPS from the parental strain did. The 31P nuclear magnetic resonance (NMR) spectrum of PXB-resistant type LPS showed that it contained much less of the phosphomonoesters and the pyrophosphate esters, and an increased amount of the phosphodiesters, compared to the parental type LPS. The decrease in the binding of PXB might be due to altered phosphate groups on the PXB-resistant type LPS, suggesting that it might explain the PXB-resistance of the mutant. 相似文献
952.
Coordination of karyokinesis of two nuclei in individual filamentous binucleate cells of the fern,Adiantum capillus-veneris was investigated. To induce binucleate cells, the protonemata were treated with caffeine, which is known as an inhibitor
of plant cytokinesis, during the first synchronous division of cells that was induced by blue light (BL). The next synchronous
division of cells in the resultant binucleate cells was analysed.
In most cases, the two nuclei were associated with each other and were located in the apical region of the long protonemal
cells (approximately 400–600 μm in length, 20 μm in width). In some cells, one nucleus was located in the apical region and
the other was located in the middle of the cylinderical region. In such cells, karyokinesis of the apical nucleus preceded
that of the basal nucleus, even though karyokinesis of associated nuclei progressed synchronously. Mitotic binucleate cells
were centrifuged in order to gather two dissociated heterophasic nuclei. Progression of karyokinesis in the re-associated
nuclei became coordinated within 1 h in most cells.
These results suggest that mitosis-regulating factor(s) may diffuse to only limited distances inAdiantum protonemata. 相似文献
953.
A maximum cell density of 8×106 viable human fibroblast cells/ml was obtained on microcarriers at a perfusion rate of 0.6 mL/min — a rate which maintained a quasi-steady state. The maximum tPA production was approximately 1.2 g/ml and obtained when the cell density was relatively constant during the later periods of cultivation. Specific UTP and tPA production rates had a correlation factor of 0.85, and cell growth to oxygen consumption had an 0.92 correlation factor. ATP generation was strongly correlated to glutamine consumption, with a lower correlation to oxygen utilization. 相似文献
954.
Masami Watanabe Tatsuo Kiyohara Ken-Ichirou Murata Junji Yodoi Hideyo Itakura 《Microbiology and immunology》1993,37(4):317-323
Cytolytic process which was affected by cholera toxin (CT) resulting in the loss of natural killer (NK) cell activity was analyzed. Conjugate formation assay, membrane phospholipid methylation assay and serine esterase (granzyme A) release assay were used to determine the stage of the CT-induced inhibition of NK cell-mediated cytotoxicity. A human NK cell line YT cell-mediated cytotoxicity was completely abolished by CT pretreatment or addition of CT to the assay system. The conjugate formation assay revealed that the binding between YT cells and target cells was not affected by CT. The defined triggering stage which is coupled with membrane phospholipid methylation was not affected by CT treatment, either. On the other hand, the lethal hit stage which is represented by serine esterase (SE) release was completely inhibited by CT treatment of YT cells. Therefore, CT inhibits the stage after binding and triggering—i.e., lethal hit stage of NK cell-mediated cytotoxicity. The results also suggest that there exists a CT-sensitive negative cytotoxic signal transduction pathway as well as usual positive signal transduction pathway and these pathways might cross talk each other in the NK cell cytotoxic process. 相似文献
955.
Yukiji Yamada Shunji Tomatsu Kazuko Sukegawa Yasuyuki Suzuki Naomi Kondo John J. Hopwood Tadao Orii 《Human genetics》1993,92(2):110-114
Southern blot analysis of the iduronate sulfatase (IDS) gene in 52 unrelated Japanese patients with mucopolysaccharidosis type II was carried out using a cDNA probe, and mutations in 13 patients (25%) were identified. Of these, 3 had partial gene deletions (in 2 the normal 9.4-kb fragment was absent and in 1 the normal 7.4-kb fragment was absent, as determined by Southern blot analysis using EcoRI-digested DNA, respectively), 2 had gene insertions (in 1 there was a unique 11.2kb fragment and in the other there was a unique 5kb fragment, determined by Southern blot analysis using EcoRI digested DNA), and 8 had rearrangements (in 6 the normal 9.4kb and 7.0kb fragments were absent and a unique 11.2kb fragment was present; in the remaining 2 patients there were different rearrangements). In these 13 patients, the similar Southern blot patterns were indicative of structural alterations of the IDS gene, as revealed when their DNA was digested with HindIII or PstI and probed with IDS cDNA. All patients with these structural alterations were in a clinically severe state, except for 1 with an intermediate clinical phenotype. Our analyses of four families among those of the 13 patients revealed that all four mothers were carriers. The detection of structural abnormalities led to a precise identification of Hunter heterozygotes and revealed one de novo rearrangement in a germ cell of one of the maternal grandparents. 相似文献
956.
Mitsuo Masuno Shunji Tomatsu Yoshihiro Nakashima Toshinori Hori Seiji Fukuda Michiya Masue Kazuko Sukegawa Tadao Orii 《Genomics》1993,16(3)
Plasmid clones of three independent genomic fragments of the gene for human N -acetylgalactosamine-6-sulfate sulfatase (GALNS; EC 3.1.6.4) were utilized in a fluorescence in situ suppression hybridization study to assign the locus to chromosome 16q24. Enzyme assay for GALNS in a patient with del(16)(q22.1) confirmed this finding. 相似文献
957.
The rplI gene encoding the ribosomal protein L9 was found 4 kbp downstream from the desA gene, but on the opposite strand, in the genome of the cyanobacterium Synechocystis PCC6803. The deduced amino acid sequence is homologous to the sequences of the L9 proteins from Escherichia coli and chloroplasts of Arabidopsis and pea. The gene is present as a single copy in the chromosome and is transcribed as a mRNA of 0.64 kb. An open reading frame of unknown function (ORF291) was found in the upstream region of the rplI gene. 相似文献
958.
The desA gene of the cyanobacterium Synechocystis sp. strain PCC6803 is the structural gene for delta 12 desaturase. 总被引:2,自引:0,他引:2
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The desA gene of the cyanobacterium Synechocystis sp. strain PCC6803 was expressed in Escherichia coli, which does not contain any fatty acid desaturase. The product of the desA gene catalyzed the desaturation of fatty acids at the delta 12 position. This result demonstrates that desA is the structural gene for a delta 12 desaturase. 相似文献
959.
Ariyuki Kagaya† Masahiko Mikuni Shin-ichiro Muraoka Kazuko Saitoh Tetsuo Ogawa Hideto Shinno† Shigeto Yamawaki† Kiyohisa Takahashi 《Journal of neurochemistry》1993,61(3):1050-1056
Abstract: Serotonin 5-HT2 receptor-mediated intracellular Ca2+ mobilization was investigated in rat glioma C6BU-1 cells. The receptors became desensitized after previous exposure to 5-HT in a time-and concentration-dependent manner. The desensitization of 5-HT2 receptor-mediated intracellular signaling appeared to be homologous because previous exposure to 5-HT did not alter the response to other transmitters such as thrombin or isoproterenol and because previous exposure to thrombin or isoproterenol did not diminish the response to 5-HT. The desensitization induced by pretreatment with 5-HT was potently prevented by the naphthalenesulfonamide derivative W-7, a calmodulin antagonist, when it was cosupplied with 5-HT. Furthermore, the preventive effect of W-7 was greater than that of W-5, a weak analogue of W-7, and than that of H-7, a nonselective inhibitor of protein kinases. These results suggest that 5-HT2 receptor-mediated Ca2+ mobilization can be desensitized homologously after prolonged exposure to 5-HT in a calmodulin-dependent manner in rat glioma C6BU-1 cells. 相似文献
960.
Mitochondrial DNA(mtDNA) analysis with restriction enzymes, Hae III, Hind III and Msp I was performed in 17Exophiala moniliae strains. The results were as follows: (1)E. moniliae could be classified into 10 types based on restriction patterns, (2)E. moniliae is suggested to be a complex organism because of extensive mtDNA polymorphism among strains likeE. jeanselmei and (3) two types ofE. moniliae are identical with two types ofE. jeanselmei. These results suggest thatE. moniliae is not genetically defined fromE. jeanselmei and the taxonomical status ofE. moniliae requires reevaluation 相似文献