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1.
Takumi Hiyoshi Hisanori Domon Tomoki Maekawa Kosuke Nagai Hikaru Tamura Naoki Takahashi Daisuke Yonezawa Tomohiro Miyoshi Akihiro Yoshida Koichi Tabeta Yutaka Terao 《Microbiology and immunology》2019,63(3-4):100-110
Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA‐treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA‐treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA‐induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis. 相似文献
2.
The effect of phosphate on the binuclear iron center of pink (reduced) uteroferrin was examined by magnetic resonance and optical spectroscopy. The purple (oxidized) protein, which contains 1 mol of tightly bound phosphate per mol of enzyme at isolation, does not give rise to a 31P NMR signal. Phosphate binding to phosphate-stripped pink uteroferrin is indistinguishable from that in the native purple phosphoprotein. As measured by EPR and optical spectroscopy, the rate of reaction between phosphate and pink uteroferrin is pH-dependent, decreasing as the pH increases. Phosphate is capable of binding to the reduced protein between pH 3 and 7.8, resulting in formation of the purple uteroferrin-phosphate complex. Evans susceptibility measurements at pH 4.9 indicate that the EPR silent species with a maximum absorption at 535 nm, generated upon phosphate addition to pink uteroferrin, is diamagnetic. Moreover, phosphate causes disappearance of the hyperfine-shifted resonances in the 1H NMR spectra of the reduced protein. We therefore have not been able to identify the paramagnetic "purple reduced enzyme-phosphate complex" reported by Pyrz et al. (Pyrz, J. W., Sage, J. T., Debrunner, P. G., and Que, Jr., L. (1986) J. Biol Chem. 261, 11015-11020) using Mossbauer spectroscopy and dithionite-reduced 57Fe-reconstituted uteroferrin. Our present data with native unmodified enzyme are in accord with our earlier results (Antanaitis, B. C., and Aisen, P. (1985) J. Biol. Chem. 260, 751-756) and with the results of Burman et al. (Burman, S., Davis, J. C., Weber, M. J., and Averill, B. A. (1986) Biochem. Biophys. Res. Commun. 136, 490-497) on bovine spleen phosphatase, suggesting that phosphate binding to reduced protein rapidly induces oxidation of the binuclear iron center. 相似文献
3.
M Ogata S Sato H Sano T Hamaoka H Doi K Nakanishi Y Asano T Itoh H Fujiwara 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(8):2675-2682
A recently established thymic stroma-derived cell line (TSCL) supported the growth of the interleukin (IL) 2-dependent, antigen-specific helper T cell (Th) clone, 9-16, without requirement for IL-2 and antigen, and such growth was substituted by a factor produced into cultures by this established TSCL. This substance, thymic stroma-derived T cell-growth factor (TSTGF), was capable of inducing the proliferation of various Th clones including 9-16 Th clone, but not of cytotoxic T cell clones. TSTGF-induced growth promotion was obtained in a dose-dependent fashion and in maintaining antigen specificity of Th clones. The culture supernatant from the TSCL did not contain detectable level of IL-1, IL-2, IL-3, IL-4, or interferon activity. The proliferation of 9-16 Th clone was stimulated by recombinant IL-2 and IL-4 as well as TSTGF, but not by IL-1, IL-3, or interferons. However, the proliferation of this Th clone by IL-2 or IL-4 was almost completely inhibited by anti-IL-2 receptor or anti-IL-4 monoclonal antibody, respectively, whereas TSTGF-induced growth of 9-16 Th clones was not affected by either type of antibody, demonstrating that TSTGF is functionally distinct from IL-2 and IL-4. In addition, TSTGF activity was also obtained from the culture supernatant of the primary thymic explant, which was freshly prepared. These results indicate that the primary thymic explant as well as an established TSCL produce factors capable of promoting the growth of helper but not cytotoxic type of T cells in the absence of T cell growth factors thus far defined. 相似文献
4.
The in vivo stability, maturation and aminoacylation of anticodon-substituted Escherichia coli initiator methionine tRNAs 总被引:1,自引:0,他引:1
H Grosjean S De Henau T Doi A Yamane E Ohtsuka M Ikehara N Beauchemin K Nicoghosian R Cedergren 《European journal of biochemistry》1987,166(2):325-332
We have constructed eight anticodon-modified Escherichia coli initiator methionine (fMet) tRNAs by insertion of synthetic ribotrinucleotides between two fragments ('half molecules') derived from the initiator tRNA. The trinucleotides, namely CAU (the normal anticodon), CAA, CAC, CAG, GAA, GAC, GAG and GAU, were joined to the 5' and 3' tRNA fragments with T4 RNA ligase. The strategy of reconstruction permitted the insertion of radioactive 32P label between nucleotides 36 and 37. tRNAs were microinjected into the cytoplasm of Xenopus laevis oocytes, and the following properties were evaluated: the stability of these eubacterial tRNA variants in the eukaryotic oocytes; the enzymatic modification of the adenosine at position 37 (3' adjacent to the anticodon) and aminoacylation of the chimeric tRNAs by endogenous oocyte aminoacyl-tRNA synthetases. In contrast to other variants, the two RNAs having CAU and GAU anticodons were stable and underwent quantitative modification at A-37. These results show that the enzyme responsible for the modification of A-37 to N-[N-(9-beta-D-ribofuranosylpurine-6-yl)carbamoyl]threonine (t6A) is present in the cytoplasm of oocytes and is very sensitive to the anticodon environment of the tRNA. Also, these same GAU and CAU anticodon-containing tRNAs are fully aminoacylated with the heterologous oocyte aminoacyl-tRNA synthetases in vivo. During the course of this work we developed a generally applicable assay for the aminoacylation of femtomole amounts of labelled tRNAs. 相似文献
5.
6.
A restricted cytoplasmic region of IL-2 receptor beta chain is essential for growth signal transduction but not for ligand binding and internalization 总被引:78,自引:0,他引:78
The functional, high affinity form of interleukin-2 receptor (IL-2R) is composed of two receptor components, the IL-2R alpha (p55) and IL-2R beta (p70-75) chains. Unlike the IL-2R alpha chain, the IL-2R beta chain contains a large cytoplasmic domain that shows no obvious tyrosine kinase motif. In the present study, we report the establishment of a system in which the cDNA-directed human IL-2R beta allows growth signal transduction in a mouse pro-B cell line. This system enabled us to identify a unique region within the cytoplasmic domain of the human IL-2R beta chain essential for ligand-mediated signal transduction. We also demonstrate that certain cytoplasmic deletion mutants in the IL-2R beta chain, although deficient in signal transduction, can still form high affinity IL-2R in conjunction with endogenous mouse IL-2R alpha chain; the mutants are still able to internalize the ligand as well. 相似文献
7.
Scale Arrangement Pattern in a Lepidopteran Wing. 1. Periodic Cellular Pattern in the Pupal Wing of Pieris rapae 总被引:1,自引:1,他引:0
In most species of lepidopteran insects, anteroposterior rows formed by scales are arranged at regular intervals in the adult wing; within each row two kinds of scales are alternately arranged. To investigate the cellular basis for the scale arrangement pattern, we examined cell arrangement in the epidermal monolayer of the pupal wing of a small white cabbage butterfly, Pieris rapae , by scanning electron microscopy and light microscopy.
The arrangement of scale precursor cells, closely resembling that of scales in the adult wing, was observed in the wing epidermis of the early pupa. Scale precursor cells are proximodistally elongated and form anteroposterior rows. Within a row two kinds of scale precursor cells are nearly alternately arranged, which is not so precise as the alternation of scales in the adult wing. Individual rows of scale precursor cells are separated by rows of single or double undifferentiated general epidermal cells. Occasionally, arrangement abnormalities occur both in the adult and the pupal wing. The cellular basis for the regular spacing of scale rows is discussed. 相似文献
The arrangement of scale precursor cells, closely resembling that of scales in the adult wing, was observed in the wing epidermis of the early pupa. Scale precursor cells are proximodistally elongated and form anteroposterior rows. Within a row two kinds of scale precursor cells are nearly alternately arranged, which is not so precise as the alternation of scales in the adult wing. Individual rows of scale precursor cells are separated by rows of single or double undifferentiated general epidermal cells. Occasionally, arrangement abnormalities occur both in the adult and the pupal wing. The cellular basis for the regular spacing of scale rows is discussed. 相似文献
8.
L F Wang R H Doi L F Chuang B I Osburn J Maisonnave E Benjamini R Y Chuang 《Biochemical and biophysical research communications》1989,162(2):892-899
The cDNA coding for the major nonstructural protein, NS1, of bluetongue serotype 17 (BTV-17) was cloned previously. Using pUC plasmids, we have successfully expressed the NS1 protein in Escherichia coli as a LacZ-NS1 fusion protein. The recombinant NS1 protein reacted with rabbit anti-BTV-17 antiserum, and was thus immunologically indistinguishable from the native BTV-17 NS1 protein. This was the first bluetongue viral protein to be produced in a bacterial system. 相似文献
9.
New mutations fts-36, lts-33, and ftsW clustered in the mra region of the Escherichia coli chromosome induce thermosensitive cell growth and division. 总被引:11,自引:7,他引:4
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F Ishino H K Jung M Ikeda M Doi M Wachi M Matsuhashi 《Journal of bacteriology》1989,171(10):5523-5530
Three new mutants of Escherichia coli showing thermosensitive cell growth and division were isolated, and the mutations were mapped to the mra region at 2 min on the E. coli chromosome map distal to leuA. Two mutations were mapped closely upstream of ftsI (also called pbpB), in a region of 600 bases; the fts-36 mutant showed thermosensitive growth and formed filamentous cells at 42 degrees C, whereas the lts-33 mutant lysed at 42 degrees C without forming filamentous cells. The mutation in the third new thermosensitive, filament-forming mutant, named ftsW, was mapped between murF and murG. By isolation of these three mutants, about 90% of the 17-kilobase region from fts-36-lts-33 to envA could be filled with genes for cell division and growth, and the genes could be aligned. 相似文献
10.
Riichi Tawa Tetsuya Ono Akihiro Kurishita Shigefumi Okada Shingo Hirose 《Differentiation; research in biological diversity》1990,45(1):44-48
DNA methylation in an adult mammalian body shows tissue-specificity. But when and how the specificity is established in the process of development has not yet been elucidated. Here we have investigated age-dependent changes in the amount of 5-methyldeoxycytidine (5mdC) that DNA of various mouse tissues contains during the late-fetal and postnatal periods, using high-performance liquid chromatography. The tissue-specificity in the 5mdC level was observed in the late-fetal stage, and the level continued to change during the subsequent periods. The most pronounced alterations were observed in brain and liver, where similar biphasic changes were seen, but at different ages. At maturation, the 5mdC levels were high in thymus, spleen and brain, intermediate in lung, and low in liver and sperm. The data demonstrate the importance of the peri- and postnatal periods in establishment of tissue-specificity in 5mdC content. 相似文献