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41.
Toshio Hirano Osamu Teraoka Tsuyoshi Teranishi Izuo Tsityuguchi Hiroko Tohda Atsushi Oikawa 《Microbiology and immunology》1980,24(9):879-886
Autoantibody-producing B cell lines were established from peripheral blood lymphocytes of patients with systemic lupus erythematosus. Peripheral blood lymphocytes obtained from five of seven patients were successfully transformed by Epstein-Barr virus. Two of four established B lymphoblastoid cell lines examined in this study produced anti-nuclear factor antibodies and one of them produced anti-single-stranded DNA and anti-double-stranded DNA antibodies. These results indicate that B cell clones committed to self antigens are transformed by Epstein-Barr virus and continue to produce autoantibodies. In order to establish a monoclonal autoantibody-producing B cell line, the cells were cloned by a limiting dilution method. The data suggest that it is possible to establish a monoclonal autoantibody-producing B cell line by the combination of transformation of B cells by Epstein-Barr virus and extensive cloning. 相似文献
42.
T Sekiguchi M Tosu M C Yoshida A Oikawa K Ishihara H Fujiki M Tumuraya T Kameya 《Somatic cell genetics》1982,8(5):605-622
Chloramphenicol-resistant (CAPr) reconstituted cells and cybrids were isolated by fusion of karyoplasts (or intact cells) of mouse amelanotic melanoma B16 cells with cytoplasts of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) -deficient, CAPr rat myoblastic cells, L6TG.CAPr, and double selection in HAT medium containing CAP. Reconstituted cells or cybrids exhibited unique cellular arrangement, and about one third of the isolated clones expressed high tyrosinase activity and marked melanin synthesis, although the parental mouse cells expressed low tyrosinase activity and the parental rat cells did not express tyrosinase activity. These phenotypic changes have been stable for more than a year. The phenotypic reversions of these clonal cells were induced by treatment with a tumor promoter. There were changes in the morphology of the treated cells to that of the mouse B16 cells and extinction of tyrosinase activity and melanin synthesis in pigmented clonal cells. These phenotypic changes and reversions induced by a promoter were repeatedly reversible. 相似文献
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Antitumour glucans (GU) from the fungus Grifora umbellata have been subjected to periodate oxidation, Smith degradation, methylation analysis, and treatment with endo-(1 leads to 6)-beta-D-, endo-(1 leads to 3)-beta-D-, and exo-(1 leads to 3)-beta-D-glucanases, and alpha-amylase; the following structural features were revealed. GU-2 contains a backbone involving (1 leads to 6)-beta- and () leads to 3)-beta linkages, and two kinds of branches involving (1 leads to 6)-beta and (1 leads to 4)-alpha linkages. GU-3 has a (1 leads to 3)-beta-linked backbone and branches involving (1 leads to 6)-beta linkages or (1 leads to 4)-alpha and (1 leads to 6)-beta linkages. GU-4 also contains a (1 leads to 3) beta-D-glucan backbone and a small number of (1 leads to 6)-beta-linked branches. Probable structural units of these glucans are proposed. 相似文献
45.
When added to Eagle's Minimum Essential Medium supplemented with 10% bovine serum (MEM-10BS), 1mM cysteine was highly toxic to cultured cells. This toxicity was eliminated by (a) preincubation of the medium at 37 degrees C for 24 hr before use, or (b) presence of 5mM pyruvate. Similar results were obtained with freshly prepared CMRL 1066 supplemented with 10% bovine serum (CMRL-10BS), which contains 1.5 mM cysteine as an original ingredient. Medium L 15 supplemented with 10% bovine serum (L-10BS), which contains both 1 mM cysteine and 5 mM pyruvate, supported cell growth. On incubation of MEM-10BS supplemented with 1 mM cysteine (MEM-10BS-1CySH) or CMRL-10BS without cells for one day, the cysteine concentrations decreased to about one-tenth or less of the original concentrations. The cysteine concentration in L-10BS did not decrease so much on similar incubation. Pyruvate reduced the rate of disappearance of the cysteine in MEM-10BS-1CySH or CMRL-10BS as assayed with p-chloromercuribenzoate, although less than that in L-10BS. This effect of pyruvate was concentration dependent. These paradoxical effects of pyruvate on cysteine, i.e. the reduction of its cytotoxicity and the stabilization as an SH compound, are probably due to the formation of a dissociable complex between these two compounds, which is not cytotoxic and resistant to oxidation. 相似文献
46.
An endo-(1→6)-β-D-glucanase (EC 3.2.1), isolated from the culture filtrate of Mucor hiemalis, was purified by ammonium sulphate fractionation and gel filtration. The homogeneity of the enzyme was confirmed by disc electrophoresis. The enzyme had a wide range of temperature and pH stability, high substrate specificity, and an action pattern of the endo-type. 相似文献
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48.
The ultraviolet circular dichroism of muscle proteins 总被引:4,自引:0,他引:4
49.
Extracellular d-glucosyltransferases (GTase) and d-fructosyltransferases (FTase) were isolated from Streptococcus mutans IB (serotype c), B14 (e), and OMZ175 (f) by chromatofocusing, followed by hydroxyapatite column chromatography. The GTases isolated from serotypes c, e, and f are basic proteins (pI 7.4). The serotype c and e enzymes have two protein components having Mr 173 000 and 158 000 and the enzyme of the serotype f one component having Mr 156 000. The GTases of all the serotypes showed a Km value for sucrose of 10–14mm and an optimum pH 5.5–6.0 for enzyme activity, and their activities were enhanced by the presence of primer Dextran T10. The α-d-glucans synthesized by the purified GTases are water soluble and primarily consist of (1→6)-α-d-glucosidic linkage (41–66 mol/100 mol) and α-d-(1→3,6)-branch linkage (6–20 mol/100 mol), but significant proportions of α-d-(1→3), α-d-(1→4), and α-d-(1→3,4) linkages (11, 6, and 14 mol/100 mol, respectively) were detected in the serotype c α-d-glucan. The isolated FTases of the serotypes c, e, and f are acidic enzymes (pI 4.6) and consist of two components having Mr 84 000 and 76 000 for the serotype c enzyme, and 106 000 and 84 000 for the serotypes e and f enzymes, respectively. The Km value for sucrose was 6, 10, and 17mm for the serotypes c, e, and f enzymes, respectively, and the optimum pH of enzymic activity 5.5–6.0. Reactivity with Concanavalin A, susceptibility to acid hydrolysis, and paper chromatography of the hydrolyzates suggested that the water-soluble β-d-fructans synthesized by the purified FTases were of the inulin-type and had chemical structures somewhat different among the serotypes. 相似文献
50.
We studied the life cycle of the riffle beetle Leptelmis gracilis Sharp, 1888 from a population located in a river stream with lotic environments. Samples were collected monthly, between September 2018 and August 2019, from a tributary of the Hiikawa River in Izumo city, Shimane Prefecture, Honshu, Japan. Larvae were separated into five distinct groups based on size. The first and last instar larval sizes were identified through rearing methods. From these results, we determined that the larval stage of this species consists of five instars. From the monthly evaluations, the number of individuals corresponding to each instar period suggested that last-instar larvae were dominant in May and that new adults emerged from July to August. Landing and pupation were estimated to occur from May to June. Monthly observations revealed that mature eggs were present in the female abdomen from April to June, as well as from August to September. It is, therefore, predicted that overwintering adults mainly oviposit from spring to early summer, while new adults oviposit from late summer to early autumn. 相似文献