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81.
Rejection of B16 melanoma induced by expression of a transfected major histocompatibility complex class I gene. 总被引:1,自引:0,他引:1
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Transfection of a functional major histocompatibility complex class I gene into certain tumor cells, induced by oncogenic viruses or chemical carcinogens, can effectively abrogate their tumorigenic activity. Since experimentally induced tumors possess strong tumor-specific transplantation antigens, expression of cell surface class I antigens may present the tumor cells to appropriate immune effector cells. Most spontaneously arising tumors do not possess tumor-specific transplantation antigens, and their tumorigenicity may not be affected by the expression of a transfected class I gene. We demonstrate that the poorly immunogenic B16-BL6 melanoma can be rendered nontumorigenic in syngeneic mice by the expression of the class I H-2K antigen but not the class II I-A antigen. Furthermore, the poorly tumorigenic, class I-expressing B16-BL6-transfected cells can effectively immunize syngeneic C57BL/6 mice against the highly tumorigenic, class I-deficient B16-BL6 parental cells. Our success in experimentally manipulating the tumorigenicity of a spontaneously derived neoplasm offers hope for a potential modality for the effective treatment of human cancer. 相似文献
82.
Anaerobic bacteria degrading 2-methoxyethanol were enriched from freshwater sediments, and three strains were isolated in pure culture. Two of them were Grampositive non-spore-forming rods and grew strictly anaerobically by acetogenic fermentation. Optimal growth occurred at 30°C, initial pH 7.5–8.0. 2-Methoxyethanol and 2-ethoxyethanol were fermented to acetate and corresponding alcohols. Hydrogen plus carbon dioxide, formate, acetoin, l-malate, lactate, pyruvate, fructose, and methoxyl groups of 3,4,5-trimethoxybenzoate and 3,4,5-trimethoxycinnamate were fermented to acetate. 1,2-Propanediol was fermented to acetate, propionate, and propanol. Strain MuME1 was described as a new species, Actetobacterium malicum. It had a DNA base composition of 44.1 mol% guanine plus cytosine. The third strain, which was identified as Pelobacter venetianus, fermented 2-methoxyethanol to methanol, ethanol, and acetate. 相似文献
83.
Summary In colchicine-pretreated cells of sympathetic ganglia, intensely NPY-immunoreactive material was localized within vacuoles and vesicles of the disorganized, widely dispersed Golgi apparatus. Intensely positive large granular vesicles, which are known to be one of major storage sites of various peptides in the autonomic nerve endings, were essentially unobserved in the perikaryal cytoplasm. The present finding provides evidence that one pool of NPY-like immunoreactivity is localized in the Golgi apparatus of colchicine-pretreated as well as normal sympathetic ganglion cells. It is also clear that visualization of NPY-immunoreactive somata by colchicine-pretreatment in the sympathetic ganglia is due to the accumulation of the neuropeptide in the disorganized Golgi stacks instead of increased amount of the large granular vesicles containing NPY. 相似文献
84.
The protein factor which binds to the upstream activating sequence of Saccharomyces cerevisiae ENO1 gene. 总被引:11,自引:2,他引:9
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Using a gel retardation assay it was shown that the 87 bp DNA fragment (UAS87) containing the upstream activating sequence (UAS) of S. cerevisiae EN01 gene and a nuclear extract gave rise to three migration-retarded species specific to UAS87. Heat- or proteinase-treatment of the nuclear extract revealed that these species were protein-DNA complexes. The precise binding region of the protein identified by DNaseI protection analysis was found to include a CCAAACA sequence which forms a dyad-symmetrical structure. The amount of one of the three migration-retarded species significantly increased when cells were grown in medium containing a gluconeogenic carbon source. The introduction of pGCR8, a multicopy plasmid containing GCR1 gene, a regulatory gene controlling the expression of several glycolytic enzymes, showed no effect on the amount of three migration-retarded species. 相似文献
85.
The complete nucleotide sequence of the gene for batroxobin, a thrombin-like snake venom enzyme. 总被引:1,自引:0,他引:1
N Itoh N Tanaka I Funakoshi T Kawasaki S Mihashi I Yamashina 《Nucleic acids research》1988,16(21):10377-10378
86.
J Mashimo C Tanaka S Arata Y Akiyama S Hata T Hirayama K Egawa N Kasai 《Microbiology and immunology》1988,32(7):653-666
The relation of chemical structure to local Shwartzman activity of lipid A preparations purified by thin-layer chromatography from five bacterial strains was examined. Two lipid A fractions from E. coli F515--Ec-A2 and Ec-A3--exhibited strong activity, similar to that of previous synthetic E. coli-type lipid A (compound 506 or LA-15-PP). The Ec-A3 fraction contained a component that appeared to be structurally identical to compound 506, and the main component of Ec-A2 fraction was structurally similar to compound 506 except that it carried a 3-hydroxytetradecanoyl group at the C-3' position of the backbone in place of a 3-tetradecanoyloxytetradecanoyl group. Free lipid A (12 C) and purified lipid A fractions, Ec-A2 (12 C) and Ec-A3 (12 C), respectively, obtained from bacteria grown at 12 C, exhibited activity comparable to Ec-A2 or Ec-A3. In these preparations, a large part of the 3-dodecanoyloxytetradecanoyl group might be replaced by 3-hexadecenoyloxytetradecanoyl group. Salmonella minnesota R595 free lipid A also contained at least two active lipid A components as seen in E. coli lipid A, but the third component corresponding to the synthetic Salmonella-type lipid A (compound 516 or LA-16-PP) exhibited low activity. A lipid A fraction, Cv-A4 from Chromobacterium violaceum IFO 12614, which was proposed to have two acyloxyacyl groups at the C-2 and C-2' positions with other acyl groups, exhibited weaker activity than the free lipid A or LPS. The purified lipid A fractions from Pseudomonas diminuta JCM 2788 and Pseudomonas vesicularis JCM 1477 contained an unusual backbone with 2,3-diamino-2,3-dideoxy-D-glucose disaccharide phosphomonoester, and these lipid A (Pd-A3 and Pv-A3) exhibited strong activity comparable to the E. coli lipid A. Thus, the present results show that the local Shwartzman reaction can be expressed by partly different lipid A structures in both hydrophilic backbone and fatty acyl residues; when they have the same backbone the potency varies markedly depending on the structure of the acyl residues. 相似文献
87.
88.
Isamu Tanaka Akio Horie Joji Haratake Yasushi Kodama Kenzaburo Tsuchiya 《Biological trace element research》1988,16(1):19-26
There are few inhalation studies of nickel carcinogenesis. In this study, Wistar male rats were exposed to green nickel oxide
(NiO(G)) aerosols (mass median aerodynamic diameter, 0.6 μm) for 7 h/d, 5 d/wk for up to 12 mo. The average exposure concentration
was controlled at 0.3 and 1.2 mg/m3 during the exposure. For histopathological examination and measurement of the nickel concentration in rat organs, the rats
were sacrificed at 3, 6, and 12 mo of exposure and 8 mo clearance period following 12 mo of exposure.
The nickel content in rat lungs that was observed up to 2.6 mg after 12 mo exposure, was proportional to the exposure concentration
during the exposure. The clearance of the nickel from the lungs was very slow and the biological half time was determined
7.7 mo.
Although the rats were exposed continuously to NiO(G), for 12 mo and kept for 8 mo clearance period, there were no malignant
tumors in any of the exposed animals. 相似文献
89.
Reinhard Renneberg Kenji Sonomoto Shigeo Katoh Atsuo Tanaka 《Applied microbiology and biotechnology》1988,28(1):1-7
Summary The oxygen-diffusivity (D
m
) of 16 different gels formed with synthetic prepolymers (photo-crosslinkable resins, urethane resins and photosensitive resins), and that of calcium alginate (for comparison) was determined, using an oxygen electrode covered by the gel membranes with stepwise enzymatic removal of O2 from the buffer solution. The water content of the gels was found to be decisive for the O2-diffusivity of the gels: gels with the highest water content showed also the highest D
m
. From these findings, the suitability of different polymeric gels for substrate conversion and biosensor systems could be predicted.Abbreviations
A
surface area of the cathode
-
c
O2-concentration in the membrane
-
d
m
total thickness of the membrane
-
D
m
O2-diffusivity in the membrane
- ENT, ENTP
polymers prepared from hydroxyethylacrylate
- ENTA, ENTC
isophorone diisocyanate and linear skeleton of different molecular weight of poly(ethylene glycol) (ENT) or poly(propylene glycol) (ENTP), resp. ENTA in addition bears anionic groups, ENTC cationic groups
-
F
Faraday's constant
-
i
s
steady-state O2 reduction current
-
N
number of electrons per mole unit of reaction
- PU
polyurethane polymers with poly(ethylene glycol) and poly(propylene glycol) parts in the diol moiety and isocyanate functional groups at both terminals of the prepolymer
- PVA-SbQ
polyvinyl alcohol stilbazolium polymer 相似文献
90.
Effects of denaturation with HCl on the immunological staining of bromodeoxyuridine incorporated into DNA 总被引:2,自引:0,他引:2
Immunochemical procedures for detection of BrdUrd incorporated into DNA require a denaturation step of DNA. Denaturation with HCl is widely used for flow cytometric analysis of the cell cycle and for histological preparations. This brief communication describes an attempt to standardize a denaturation procedure with HCl. Various denaturation conditions at 20 degrees C were examined for human promyelocytic leukemia cells (HL-60 cells) fixed in ethanol. After denaturation of DNA, the cells were stained by an indirect immunofluorescence method using a commercially available monoclonal anti-BrdUrd antibody or by propidium iodide. The relative fluorescence intensities of stained BrdUrd and double-stranded DNA were altered reciprocally by changing HCl concentration and/or denaturation time. Treatment with 4N HCl for 10-20 min at 20 degrees C allowed denaturation of more than 80% of DNA and the maximum BrdUrd-linked immunofluorescence. Under this condition, the coefficient of variation of the DNA histograms remained relatively small. 相似文献