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Shinji Yamasaki Zaw Lin Hiromasa Shirai Akito Terai Yuichi Oku Hideaki Ito Mari Ohmura Tadahiro Karasawa Teizo Tsukamoto Hisao Kurazono Yoshifumi Takeda 《Microbiology and immunology》1996,40(5):345-352
To identify the type of Verotoxins (VT) produced by Verocytotoxin-producing Escherichia coli (VTEC), a sensitive bead-enzyme-linked immunosorbent assay and polymerase chain reaction with common and specific primers to various VTs (VT1, VT2, VT2vha, VT2vhb, and VT2vp1) were developed. Together with colony hybridization tests with oligo- and polynucleotide probes, these methods were applied to VTEC isolates to type the VT produced. The toxin types of 26 of 37 strains were identified, but the reaction profiles in assays of the remaining 11 strains suggested the existence of new VT2 variants. The application of these identification procedures may be useful as a tool for clinical and epidemiological studies of VTEC infection. 相似文献
4.
Zhao Ying Hiromasa Tojo Takanori Komatsubara Manabu Nakagawa Masami Inada Sumio Kawata Yuji Matsuzawa Mitsuhiro Okamoto 《生物化学与生物物理学报:疾病的分子基础》1994,1226(2):201-205
Enzyme activity, protein contents, and mRNA contents of group II phospholipase A2 (PLA2) in hepatocellular carcinoma (HCC) surgically obtained from 8 patients were compared with those in either its neighboring liver tissues or control liver tissues. The PLA2 specific activity towards the mixed micelles of 1-palmitoyl-2-oleoyl-phosphatidylglycerol and cholate was significantly greater in the tumor tissues (6.62 ± 1.46 nmol/min/mg) than those in the surrounding liver tissues (1.33 ± 0.22 nmol/min/mg) and controls (0.43 ± 0.04 nmol/min/mg). The results of immunoblot analysis using a specific anti-human group II PLA2 antibody and of Northern blot analysis using a human group II PLA2 cDNA as a probe demonstrated that group II PLA2 was responsible for the increased enzyme activity. The contents of immunoreactive group II PLA2 in the tumor tissues (8.81 ± 1.24 ng/mg) were significantly higher than those in the surrounding liver tissues (1.77 ± 0.27 ng/mg); those in the control tissues were below the analytical range of the method used. The group II PLA2 mRNA was also significantly increased in the tumor tissues, compared with that in the surrounding liver tissues, whereas it was not detectable in th controls. This indicates that group II PLA2 in HCC is induced at the pretranslational level. 相似文献
5.
Shinji Hosoi Mitsuo Satoh Hiromasa Miyaji Tatsunari Nishi Tamio Mizukami Mamoru Hasegawa Seiga Itoh Tatsuya tamaoki 《Cytotechnology》1995,19(1):1-10
Pro-UKS1 was designed as a thrombin-resistant derivative of pro-urokinase (pro-UK) by introducing a glycosylation site using site-directed mutagenesis. An expression plasmid for pro-UKS1, pMo1UKS1SEd1-5, was constructed and introduced into Namalwa KJM-1 cells (Hosoiet al., 1988), and cells resistant to G418 and Methotrexate (MTX) were obtained. Amongst them, the highest pro-UKS1 producer (resistant to 500 nM of MTX), clone 41-8, was selected and further characterized. Clone 41-8 was cultured in serum-free ITPSGF medium (Hosoiet al., 1988). Under the conventional conditions, the concentration of pro-UKS1 reached 26 g ml–1. Addition of glucose and tri-iodothyronine (T3) improved productivity, and the maximal productivity of pro-UKS1 was 67 g ml–1 day–1. In this conditioned medium, content of pro-UKS1 was above 80% of total proteins.Abbreviations BSA
bovine serum albumin
- dhfr
dihydrofolate reductase
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- kb
kilobase pairs
- kDa
kilodaltons
- MTX
Methotrexate
- PBS
phosphate buffered saline
- pro-UK
pro-urokinase
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- T3
tri-iodothyronine
- Tween-PBS
phosphate buffered saline containing 0.05% Tween 80 相似文献
6.
Hiromasa Kijima Taisaku Amakawa Michio Nakashima Hiromichi Morita 《Journal of insect physiology》1977,23(4):469-479
Previously reported PII-type α-glucosidase located in the precipitate of the labellar homogenate of the blowfly Phormia regina was solubilized by sodium deoxycholate (DOC) and further separated into three isozymes with different molecular weight: PII-M (mol. wt 9 × 104). PII-D (mol. wt 2 × 105) and PII-T (mol. wt 8 × 105) by molecular sieve chromatography on Biogel P-300 or Ultragel AcA-34. These three isozymes had almost the same Km's and relative values of Vm's for several substrates, suggesting that they had the same common active site.PII-D and PII-T are more strongly embedded in the membrane than PII-M, because the proportion of PII-D and PII-T was much increased when the remaining glucosidase in the precipitate after the first solubilization was reextracted by DOC. A large peak of α-glucosidase isozyme P-IV which preferentially hydrolyze sucrose eluted just after P-II (soluble P-II) when the supernatant fraction of the labellar homogenate was chromatographed on DEAE-Sephadex A-50. P-IV was scarcely present in the precipitate fraction.Soluble P-II had the same mol. wt as PII-M and had similar properties to PII-M except for the ratio of Vm's.A large proportion of PII-D was contained in the well washed labellar integuments, a preparation rich in labellar chemosensilla. It suggests that most of the insoluble α-glucosidase contained in the dendrite in labellar chemosensilla is PII-D. PII-D (and PII-T) are possible sites of the pyranose receptor molecule because their properties and localization agree well with those of the receptor. 相似文献
7.
What is the precise molecular mechanism of semi-conservative DNA replication? After the great efforts of the past 20 years, molecular biology has now established the discontinuous syntheses of daughter DNA on both of the parental strands. In order to explain this type of discontinuous replication, we introduce the concept of a palindromic primer.First we focus our attention on various oligomers (RNA or DNA) which appear usually or occasionally in the process of replication. Then we propose the palindromic nature of these oligomers so as to serve as the primer of DNA synthesis. This postulation gives a theoretical reasoning for the discontinuities of both new strands in the fork region of replication.Subsequently we consider Watson's concatemeric intermediate theory, proposed for the explanation of replicative synthesis of phage T7 DNA. By considering the contribution of some sequence-specific endonuclease(s), we suggest the existence of partial palindromic sequences of bases at the connecting region(s) in which the redundant ends of the respective phage DNA molecules are overlapping. Another theory on the replication of linear chromosomal DNA including the concept of the terminal palindromic sequence of bases is also analyzed from the viewpoint of palindromic primer. Further, some recent experimental approaches, especially on the origin(s) of DNA replication, are shown to favour the concept of a palindromic primer. 相似文献
8.
The lattice-model of Changeux, Thiery, Tung & Kittel (1966) was extended in order to examine the co-operative response of chemically excitable membrane and the exact mathematical correspondence to the Ising model was shown. In this model, two conformational states S and R with different affinities for the ligand are assumed to be accessible to each protomer, which is interacting with the nearest-neighbor protomers. The model is applicable to any kind of symmetrically interacting system consisting of oligomers and lattices and is an extension of previously proposed models of allosteric protein. It includes the model of Monod, Wyman, & Changeux (1965) and that of Koshland, Némethy & Filmer (1966) as the extreme cases of the oligomer. By assuming that a state-transition from S to R in a protomer is accompanied by a unit increase in conductance, the characteristics of dose-response curves of chemically excitable membrane are examined. The Hill's coefficient nH of dose-response curve, the measure of the co-operativity, is shown to be proportional to the square of the mean fluctuation of the state function, the fraction of protomers in R state. 相似文献
9.
Based on statistical variance as an index of electroencephalogram (EEG) parameters, we monitored slow-wave sleep in both humans and rats in real time and on-line with a widely used personal computer. This EEG variance method may be a useful tool to carry out biological rhythm research, including sleep studies. 相似文献
10.
The tautomerism of sugars showing complex mutarotation has been analyzed mathematically based on a scheme of three components. More-complete but complex schemes are shown to be reducible to the three-component scheme, because the supposed intermediates of interconversion can be neglected in the kinetics when their equilibrium contents are very small and because two furanose tautomers can be regarded as one component under appropriate conditions. The kinetics of the three-component scheme have been fully studied and are shown to explain successfully the tautomerism of most of the sugars. The tautomerism of D-galactose has been analyzed in especial detail. From the polarimetric data and the equilibrium content of α-pyranose, the kinetic rate-constants for D-galactose were determined and found consistent with all other experimental data. The slow and fast processes of complex mutarotation of D-galactose are shown to correspond approximately to pyranose-pyranose and pyranose-furanose interconversions, respectively. 相似文献