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1.
Haruhide Kawabe Hiroshi Naganawa Shinichi Kondo Hamao Umezawa Susumu Mitsuhashi 《Microbiology and immunology》1978,22(9):515-521
A clinical isolate of Staphylococcus aureus resistant to gentamicin, kanamycin and 3′,4′-dideoxykanamycin B contained two enzymes capable of inactivating gentamicin, i.e., an aminoglycoside 2″-phosphotransferase and aminoglycoside acetyltransferase. 相似文献
2.
Shinichi Ikemoto Seiji Wada Masato Kamizuru Nobuyuki Hayahara Taketoshi Kishimoto Masanobu Maekawa 《Cancer immunology, immunotherapy : CII》1992,34(5):289-293
Summary The authors examined interleukin-2 (IL-2) production and interferon (IFN) production of peripheral blood mononuclear cells in 28 patients with renal cell carcinoma and 17 control subjects. The peripheral blood was obtained prior to the initiation of therapeutic procedures. The patients were divided into two groups according to tumor size, 5 cm and >5 cm. The production of IL-2 and IFN was measured by immunoradiometric assay. As a result, in the patients with tumors >5 cm, IL-2 and IFN production was impaired. However, in the patients with tumors 5 cm, IFN production was enhanced, though IL-2 production was not significantly different from that of the control subjects. There was no significant correlation between IL-2 production and IFN production. 相似文献
3.
The mutagenicity of the base analogue, 2-amino-N6-hydroxyadenine (AHA), was tested in Salmonella typhimurium TA100 and TA98 and in Chinese hamster lung (CHL) cells. AHA showed very potent mutagenicity in TA100 without S9 mix, inducing 25,000 revertants/micrograms. The mutagenicity increased about 2-fold upon addition of S9 mix containing 10 microliters S9. AHA was found to be one of the strongest mutagens for TA100. Addition of S9 mix containing 100 microliters S9 induced no significant increase of revertants with AHA at amounts up to 50 ng per plate. AHA was also mutagenic for the frameshift mutant, TA98, without S9 mix, the mutagenicity for TA98 being about 1/1000 of that for TA100. When the mutagenicity of AHA was tested in CHL cells, with diphtheria toxin resistance (DTr) as a selective marker in the absence of S9 mix with a 3-h treatment of cells, DTr mutants increased dose-dependently at concentrations of 2.5-15 micrograms/ml. When cells were incubated with AHA for 24 h, a 200-fold increase in the number of DTr mutants was observed; the mutagenicity was 500-fold higher than that of ethyl methanesulfonate. This marked increase of mutagenicity by prolonged incubation may indicate that AHA induces mutations mainly after incorporation into DNA. The addition of a small amount of S9 increased the mutagenicity obtained with a 3-h treatment 2-fold, but a larger amount of S9 decreased the mutagenicity as was found with S. typhimurium TA100. 相似文献
4.
Nalidixic acid-resistant mutations of the gyrB gene of Escherichia coli 总被引:41,自引:0,他引:41
Jun-ichi Yamagishi Hiroaki Yoshida Michiko Yamayoshi Shinichi Nakamura 《Molecular & general genetics : MGG》1986,204(3):367-373
Summary DNA fragments of 3.4 kb containing the gyrB gene were cloned from Escherichia coli KL-16 and from spontaneous nalidixic acid-resistant mutants. The mutations (nal-24 and nal-31) had been determined to be in the gyrB gene by transduction analysis. Nucleotide sequence analysis of the cloned DNA fragments revealed that nal-24 was a G to A transition at the first base of the 426th codon of the gyrB gene, resulting in an amino acid change from aspartic acid to asparagine, and nal-31 was an A to G transition at the first base of the 447th codon, resulting in an amino acid change from lysine to glutamic acid. This indicates that mutations in the gyrB gene are responsible for nalidixic acid resistance. 相似文献
5.
Summary Dynamic change of plastid nucleoids (pt nucleoids) was followed by fluorescence microscopy after staining with 46-diamidino-2-phenyl indole (DAPI). The fluorescence image was quantified with a supersensitive photonic microscope system based on photon counting and image analysis. The results showed that small pt nucleoids located in the center of proplastids in the dry seed increased in size after imbibition and formed highly organized ring structures in the dark, which divided into ca. 10 pieces within 3 days. Corresponding to this morphological change, DNA content of a plastid multiplied 7.5 fold. Total increase in DNA content of pt nucleoids per cell was 34 times as that of dry seed, as plastid multiplied 4.6 times in the average during this period. Upon light illumination small pt nucleoids having basic genome size were separated from divided pt nucleoids, suggesting a relationship with the formation of thylakoid system. The significance of the procedure established in this study is discussed in analysing the dynamic changes of intracellular small genomes.On leave from Department of Biology, Faculty of Science, Nagoya University, Furocho, Chikusaku, Nagoya 464, Japan. 相似文献
6.
Duško Ili? Satoshi Kanazawa Yasuhide Furuta Tadashi Yamamoto Shinichi Aizawa 《Experimental cell research》1996,222(2):298
Focal adhesion kinase (FAK) is a novel nonreceptor protein tyrosine kinase that localizes in focal adhesions. It is expressed in a variety of cell types, and we reported earlier that its deficiency causes a decrease of mobility in mesodermal cells with enhanced formation of focal adhesions. With embryoid bodies generated from embryonic stem cells, we also observed a decrease of mobility in FAK-deficient endodermal cells with enhanced focal adhesion formation. 相似文献
7.
The in-gel competitive reassociation (IGCR) procedure was successfullyapplied to construct a comprehensive library enriched in DNAfragments containing C5mCGG sequences from mouse liver and braingenomic DNA. For IGCR, methylation-insensitive restriction enzyme(Msp I) digests were used as target DNA and methylation-sensitiverestriction enzyme (Hpa II) digests as competitor DNA. Southernblot analysis indicated that 60 to 70% of the clones in thelibrary were derived from the methylated sites and overall enrichmentwas 200- to 1000-fold. IGCR was further applied to constructa library for the sites differentially methylated between brainand liver DNA. In the library, approximately 20% of the HpaII sites exhibited different degrees of methylation betweenthese tissues. 相似文献
8.
We re-examined the distribution of chloroplast DNA (ct-DNA) in the pyrenoid core of Caulerpa okamurae Weber van Bosse and C. lentillifera J. Agardh by fluorescence microscopy after staining the squashes and Technovit sections with DNA fluorochromes such as 4′6-diamidino-2-phenylmdole (DAPI), ethidium bromide, Hoechst 33258 and chromomycin A3. All fluorochromes stained specifically the pyrenoid core on the squashes and Technovit sections. In addition, we present new data on the localization of ct-DNA in the pyrenoid core of two other species of the genus Caulerpa: C. cactoides (Turner) Agardh and C. geminata Harvey. 相似文献
9.
Shinichi Kitamura Takashi Hirano Kenichi Takeo Mitsuru Mimura Kanji Kajiwara Bjrn T. Stokke Tsutomu Harada 《International journal of biological macromolecules》1994,16(6)
The conformation and dilute solution properties of (2→1)-β-d-fructan in aqueous solution were studied by gel permeation chromatography, low-angle laser light-scattering photometry, viscometry, small-angle X-ray scattering and electron microscopy. Fractions covering a broad range of weight-average molecular weights (Mw) from 1.49 × 104 to 5.29 × 106 were obtained from a native sample by ultrasonic degradation and fractional precipitation. For Mw < 4 × 104, the intrinsic viscosity [η] varies with Mw0.71, indicating that the fructan chain behaves as a random coil expanded by an excluded-volume effect in this molecular weight region. For Mw > 105, [η] exhibits an unusually weak dependence on Mw and finally becomes almost independent of molecular weight. This behaviour is interpreted in terms of a globular conformation of the high-molecular-weight fructan molecules. Small-angle X-ray-scattering measurements and electron microscopic observations support this interpretation of the values of [η] observed. 相似文献
10.
We examined the dose response, time course and reversibility of the effect of methyl 2-tetradecylglycidate (McN-3716, methyl palmoxirate or MEP), an inhibitor of -oxidation of fatty acids, on incorporation of radiolabeled palmitic acid ([U-14C]PA) from plasma into brain lipids of awake rats. MEP (0.1, 1 and 10 mg/kg) or vehicle was administered intravenously from 10 min to 72 hr prior to infusion of [U-14C]PA. Two hr pretreatment with MEP (0.1 to 10 mg/kg) increased brain organic radioactivity 1.2 to 1.8 fold and decreased brain aqueous radioactivity by 1.2 to 3.0 fold when compared to control values. At 10 mg/kg, MEP significantly increased brain organic fraction from 40% in controls to 85%, 30 min to 6 hr pretreatment, and resulted in a redistribution of the radiolabeled fatty acid toward triacylglycerol. MEP changed the lipid/aqueous brain ratio of incorporated [U-14C]PA from 0.67 to 5.7. The incorporation rate coefficient, k*, was significantly increased by MEP (10 mg/kg) at 2 hr (31%), 4 hr (59%) and 6 hr (34%). All effects were reversed by 72 hr, consistent with a half-life of 2 days for carnitine palmitoyl transferase I. These results indicate that intravenous MEP may be used with [1-11C]palmitic acid for studying brain lipid metabolism in vivo by positron emission tomography, as it significantly reduces the large unincorporated aqueous fraction that would result in high background radioactivity. 相似文献