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1.
Staphylococcal gamma-hemolysin and leukocidin are bi-component cytolysins, consisting of LukF (or Hlg1)/Hlg2 and LukF/LukS, respectively. Here, we purified serum inhibitors of gamma-hemolysin and leukocidin from human plasma. Protein sequencing showed that the purified inhibitors of 62, 57, 50 and 38 kDa were the vitronectin fragments with truncation(s) of the C-terminal or both N- and C-terminal regions. The purified vitronectin fragments specifically bound to the Hlg2 component of gamma-hemolysin and the LukS component of leukocidin to form high-molecular-weight complexes with them, leading to inhibition of the toxin-induced lysis of human erythrocytes and human polymorphonuclear leukocytes, respectively. Intact vitronectin also showed inhibitory activity to the toxins. The ability of gamma-hemolysin and leukocidin to bind vitronectin and its fragments is a novel function of the pore-forming cytolysins. 相似文献
2.
T Tobe S Minoshima S Yamase N H Choi M Tomita N Shimizu 《Cytogenetics and cell genetics》1991,57(4):193-195
SP-40,40 is a serum glycoprotein consisting of two different subunits (alpha and beta) assembled into a dimer by disulfide bonds. Northern blot hybridization, using total RNA from several cell lines, showed that SP-40,40 is expressed in glioblastoma and testicular tumor cells, as well as hepatoma cells. Spot blot hybridization of flow-sorted human chromosomes, using a SP-40,40 cDNA fragment as a probe, localized the gene for SP-40,40 to human chromosome 8. This gene has been given the designation CLI, for complement lysis inhibitor, by the Human Gene Nomenclature Committee. 相似文献
3.
4.
The advent of social media expands our ability to transmit information and connect with others instantly, which enables us to behave as “social sensors.” Here, we studied concurrent bursty behavior of Twitter users during major sporting events to determine their function as social sensors. We show that the degree of concurrent bursts in tweets (posts) and retweets (re-posts) works as a strong indicator of winning or losing a game. More specifically, our simple tweet analysis of Japanese professional baseball games in 2013 revealed that social sensors can immediately react to positive and negative events through bursts of tweets, but that positive events are more likely to induce a subsequent burst of retweets. We confirm that these findings also hold true for tweets related to Major League Baseball games in 2015. Furthermore, we demonstrate active interactions among social sensors by constructing retweet networks during a baseball game. The resulting networks commonly exhibited user clusters depending on the baseball team, with a scale-free connectedness that is indicative of a substantial difference in user popularity as an information source. While previous studies have mainly focused on bursts of tweets as a simple indicator of a real-world event, the temporal correlation between tweets and retweets implies unique aspects of social sensors, offering new insights into human behavior in a highly connected world. 相似文献
5.
M Tsubaki H Ohkubo Y Tsuneoka S Tomita A Hiwatashi Y Ichikawa 《Biochimica et biophysica acta》1987,914(3):246-258
Three fractions of cytochrome P-450scc (denoted as fractions a, b, and c) were purified by a new procedure from bovine adrenocortical mitochondria. The amino-acid content analyses of these three fractions showed no difference. NH2-terminal amino-acid sequences of cytochrome P-450scc fractions, a and b agreed completely with the sequence deduced by nucleotide sequence of cDNA of cytochrome P-450scc mRNA (Morohashi, K., Fujii-Kuriyama, Y., Okada, Y., Sogawa, K., Hirose, T., Inayama, S. and Omura, T. (1984) Proc. Natl. Acad. Sci. USA 81, 4647-4651), whereas the sequence of fraction c showed a missing of isoleucine at the NH2-terminal. COOH-terminal ámino-acid sequences of fractions a, b and c were -Gln-Ala-COOH, identical with the deduced sequence from the cDNA. Measurements of the enzymatic activities of cholesterol side-chain cleavage reaction revealed no distinct difference among these three fractions. Although each of these fractions appeared as a single protein staining band upon SDS-polyacrylamide gel electrophoresis, these fractions showed heterogeneities upon two-dimensional electrophoresis and chromatofocusing. Fraction a contained the major form of cytochrome P-450scc, and its isoelectric point was estimated to be pH 7.8 by isoelectric focusing under both native and denatured conditions, and this value was confirmed by chromatofocusing. Neither of the carbohydrate-specific stainings (such as periodic acid-Schiff staining and lectin-peroxidase stainings using concanavalin A, wheat-germ agglutinin, and soybean agglutinin) of purified cytochrome P-450scc fractions after the electrophoretic resolution on SDS-polyacrylamide gel could show cytochrome P-450scc fractions as glycoproteins, suggesting that the heterogeneities were not due to the glycosylation state. 相似文献
6.
Effects of calcium-antagonists and calmodulin inhibitors on DNA synthesis in cultured rat vascular smooth muscle cells 总被引:1,自引:0,他引:1
To investigate the role of intracellular Ca2+ in the mechanism of cellular proliferation of vascular smooth muscle cells (VSMC), the effects of Ca2+-antagonists and calmodulin (CaM) inhibitors on DNA synthesis stimulated by serum-derived growth factors were studied in cultured VSMCs derived from rat aorta. DNA synthesis assessed by incorporation of [3H]thymidine into the cells was significantly stimulated by epidermal growth factor (EGF), platelet-derived growth factor (PDGF) or fetal bovine serum (FBS), of which the effects were dose-dependently inhibited by a variety of Ca2+-antagonists, such as verapamil, diltiazem and nicardipine. Trifluoperazine and W-7, both specific CaM inhibitors, similarly inhibited DNA synthesis stimulated by EGF, PDGF or FBS in a dose-dependent manner, whereas W-5, a less specific CaM inhibitor, was minimally effective. These data suggest that the Ca2+-CaM system plays an important role in the mechanism of growth factor-induced DNA synthesis in VSMCs. 相似文献
7.
N Imanishi T Nakayama M Asano K Yatsunami K Tomita A Ichikawa 《Biochimica et biophysica acta》1987,928(2):227-234
Dexamethasone at a concentration as low as 10 nM significantly increased both the histamine content and histidine decarboxylase activity of cultured mastocytoma P-815 cells. Both effects were clearly seen using several glucocorticoids, which were as effective as dexamethasone. In contrast to that of histamine, the serotonin level of mastocytoma P-815 cells was decreased by treatment with dexamethasone. The dexamethasone-induced increases in histamine content and histidine decarboxylase activity were completely suppressed by the addition of cycloheximide and actinomycin D. Mastocytoma P-815 cells were found to possess binding sites for [3H]dexamethasone in the cytosol (Kd = 15.7 nM) and the nuclei (Kd = 1.26 nM). These results show that glucocorticoids significantly stimulate de novo synthesis of histidine decarboxylase. 相似文献
8.
Prostaglandin D2 receptor of mastocytoma P-815 cells--possible regulation by phosphorylation and dephosphorylation 总被引:1,自引:0,他引:1
S Yoshimura Y Mizuno K Kimura K Yatsunami J Fujisawa K Tomita A Ichikawa 《Biochimica et biophysica acta》1989,981(1):69-76
The 3H-labeled prostaglandin D2 [( 3H]PGD2) binding protein in the membrane fraction of mastocytoma P-815 cells was characterized. The specific binding of [3H]PGD2 to the cells or the membranes reached a maximum at pH 5.6, and was saturable, displaceable and of high affinity when incubated at 0 or 37 degrees C. The Bmax values for [3H]PGD2 binding in the two preparations at pH 5.6 were much higher at 0 degrees C than at 37 degrees C, whereas the Kd values were almost equal (85.3 nM for the cells and 80.5 nM for the membranes, respectively). High specific [3H]PGD2 binding activity in the mildly acid-treated cells was still observed when the external pH was raised from 5.6 to 7.2. Furthermore, specific [3H]PGD2 binding to the membranes (at 0 degrees C, pH 5.6) increased on addition of phosphatase inhibitors (NaF and molybdate) in the presence of 10 microM ATP, but practically disappeared on pretreatment of the membranes with phosphatase. On incubation of the membrane with [gamma-32P]ATP and molybdate, the stimulated incorporation of the [32P]phosphate into several peptides, including ones having an Mr of around 100,000-120,000, was observed. These results suggest that [3H]PGD2 binding in the mastocytoma P-815 cell membrane is controlled through phosphorylation-dephosphorylation of the receptor itself. 相似文献
9.
T Tsuchihashi M Ueno H Muratani Y Tomita S Takishita M Fujishima 《Endocrinologia japonica》1989,36(2):237-243
We investigated the effects of sodium depletion and orthostasis on the plasma concentration and urinary excretion of vasopressin (AVP) in eight normal female subjects. After 4 days on a sodium controlled diet (130 mEq/day), the subjects were placed on a low sodium diet (30 mEq/day) for 3 days and 120 mg of furosemide was administered orally on the first day of the low sodium regimen. Sodium depletion in the present study reduced body weight by 1.6 kg and increased hematocrit by 3.5%. A significant (p less than 0.05) increase in plasma AVP and a significant (p less than 0.05) decrease in 24-h urinary excretion of AVP were observed during sodium depletion. One-hour ambulation significantly increased plasma AVP in both control and sodium depleted phases (p less than 0.01). The percent change in plasma AVP tended to correlate with that in mean blood pressure in the control phase (r = 0.69, 0.05 less than p less than 0.1), and significantly correlated in the sodium depleted phase (r = 0.86, p less than 0.01). The present results suggest that AVP may play an important role in the maintenance of blood pressure during orthostasis in the sodium depleted state. 相似文献
10.
M Furukawa S Arai T Munakata K Kuwano H Inoue K Tomita 《Nihon saikingaku zasshi. Japanese journal of bacteriology》1989,44(6):817-821
Several species of mycoplasmas including M. pneumoniae, the causative agent of human respiratory infection, were investigated for tumor necrosis factor-alpha (TNF-alpha) induction. The cytotoxic activity to Meth A cells of peritoneal macrophages purified from BALB/c mice was enhanced markedly when cultured with either viable or nonviable mycoplasmas. The supernatant of macrophage culture mixed with mycoplasmas, M. pneumoniae or A. laidlawii, showed a potent cytotoxic activity to TNF-alpha-sensitive but not to TNA-alpha-insensitive L cells. Addition of anti-TNA-alpha antiserum inhibited completely the cytotoxic activity of the supernatant, indicating that the cytotoxic activity is due mostly to TNF-alpha. These results strongly suggest that mycoplasmas possess an activity to induce TNF-alpha, which enhances the cytotoxic activity of macrophages and prevent infection with mycoplasmas in vivo. 相似文献