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981.
Ken-ichi Hisamatsu Tetsuya Ganbo Tsutomu Nakazawa Mayumi Nakajima Rei Goto Yosihiko Murakami 《Prostaglandins & other lipid mediators》1996,51(1):69-79
To clarify the effects of leukotriene C4 (LTC4) on human ciliated epithelium, ciliary activity of the ethmoid sinus mucosa was measured photoelectrically in tissue culture. At concentrations ranging from 10−6M to 10−9M, LTC4 showed minimal effects on the ciliated epithelium during the initial 30 minutes of exposure; thereafter, ciliary inhibition was observed in a concentration- and time-dependent manner. Irrigation of the mucosa with culture medium 15 minutes after exposure prevented the LTC4-induced ciliary inhibition. However, irrigation 60 minutes after exposure failed to inhibit 10−8M LTC4-induced ciliary dysfunction and mucosal damage. The LTC4-induced ciliary inhibition was blocked in the presence of FPL-55712 and/or Ly-171883, both leukotriene receptor antagonists. L-serine and sodium tetraborate complex (SBC), a γ-glutamyl transpeptidase (γ-GTP) inhibitor, also inhibited the LTC4-induced ciliary inhibition. These findings indicate that LTC4 is converted to LTD4 by γ-GTP during 60 minutes of exposure, and LTC4 itself has minimal direct effects on the ciliated cells. 相似文献
982.
A functional role for death proteases in s-Myc- and c-Myc-mediated apoptosis. 总被引:6,自引:0,他引:6 下载免费PDF全文
S Kagaya C Kitanaka K Noguchi T Mochizuki A Sugiyama A Asai N Yasuhara Y Eguchi Y Tsujimoto Y Kuchino 《Molecular and cellular biology》1997,17(11):6736-6745
Upon activation, cell surface death receptors, Fas/APO-1/CD95 and tumor necrosis factor receptor-1 (TNFR-1), are attached to cytosolic adaptor proteins, which in turn recruit caspase-8 (MACH/FLICE/Mch5) to activate the interleukin-1 beta-converting enzyme (ICE)/CED-3 family protease (caspase) cascade. However, it remains unknown whether these apoptotic proteases are generally involved in apoptosis triggered by other stimuli such as Myc and p53. In this study, we provide lines of evidence that a death protease cascade consisting of caspases and serine proteases plays an essential role in Myc-mediated apoptosis. When Rat-1 fibroblasts stably expressing either s-Myc or c-Myc were induced to undergo apoptosis by serum deprivation, a caspase-3 (CPP32)-like protease activity that cleaves a specific peptide substrate, Ac-DEVD-MCA, appeared in the cell lysates. Induction of s-Myc- and c-Myc-mediated apoptotic cell death was effectively prevented by caspase inhibitors such as Z-Asp-CH2-DCB and Ac-DEVD-CHO. Furthermore, exposing the cells to a serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), also significantly inhibited s-Myc- and c-Myc-mediated apoptosis and the appearance of the caspase-3-like protease activity in vivo. However, AEBSF did not directly inhibit caspase-3-like protease activity in the apoptotic cell lysates in vitro. Together, these results indicate that caspase-3-like proteases play a critical role in both s-Myc- and c-Myc-mediated apoptosis and that caspase-3-like proteases function downstream of the AEBSF-sensitive step in the signaling pathway of Myc-mediated apoptosis. 相似文献
983.
Takayoshi Suzuki Makoto Hayashi Xue Wang Kazuo Yamamoto Tetsuya Ono Brian C Myhr Toshio Sofuni 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》1997,395(1):13
We compared the induction of gene mutations and chromosomal aberrations by ethylating agents in lacZ transgenic mice (Muta™Mouse). Chromosomal aberrations were detected by the peripheral blood micronucleus assay. Gene mutations were detected in the lacZ transgene. A small amount of blood was sampled from a tail vessel during the expression time for fixation of gene mutations in vivo; this enabled us to detect and compare clastogenicity and gene mutations in the identical mouse. Single intraperitoneal injections of ENU (50–200 mg/kg) and EMS (100–400 mg/kg) strongly induced micronucleated reticulocytes (MN) detectable in peripheral blood 48 h after treatment. The maximum MN frequencies induced were 6.6% and 3.3% for ENU (100 mg/kg) and EMS (400 mg/kg), respectively (the control value was 0.3%). lacZ mutant frequency (MF) was analyzed in bone marrow and liver 7 days after treatment. Spontaneous MFs were 2.0–4.6x10−6. MF in bone marrow was increased by ENU to 3.4x10−5 at 200 mg/kg and induced by EMS to 1.8x10−5 at 400 mg/kg. In liver, however, both chemicals at their highest doses induced only slight increases in MF. The induction of both micronuclei and lacZ mutations in bone marrow by both ENU and EMS correlated better with O6-ethylguanine adducts than with N7-ethylguanine adducts. The mutants (19 for ENU and 12 for EMS) were subjected to DNA sequence analysis. Among EMS-induced mutations, 75% were GC to AT transitions, which were probably caused by O6-ethylguanine. Among ENU-induced mutations, in contrast, 40% occurred as AT base pair substitutions (6 AT to TA transversions and 2 AT to GC transitions) (no such mutations were induced by EMS). These results, together with the known reactivity of ENU to thymine suggest that thymine adducts play a significant role in the ENU mutagenesis. 相似文献
984.
Kasumi Noguchi Harushi Nakajima R. Aono 《Extremophiles : life under extreme conditions》1997,1(4):193-198
Escherichia coli and Pseudomonas aeruginosa grown in the presence of certain harmful organic solvents become susceptible to these solvents during the cultivation. This
susceptibility is conspicuous in the stationary phase of growth. The organic solvent tolerance levels of these microorganisms
were maintained when the oxygen concentration was kept high. The tolerance levels were maintained also when these organisms
were grown with nitrate present under anaerobic respiratory conditions.
Received: 21 March, 1997 / Accepted: July 20, 1997 相似文献
985.
Activating mechanism of CNTF and related cytokines 总被引:10,自引:0,他引:10
986.
Kobayashi Tetsuya Matsuno Kiyoshi Murai Masaaki Mita Shiro 《Neurochemical research》1997,22(9):1105-1109
Our previous studies have shown that three sigma () receptor ligands, (+)-N-allylnormetazocine ((+)-SKF-10,047), (±)-pentazocine and 1,3-di(2-tolyl)guanidine (DTG) differently regulated the dopamine (DA) transmission in the rat brain. In the present study, we attempted to clarify the role of 1 receptor subtype in the regulation of DA transmission using a novel and selective 1 receptor agonist, 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503) in the rat brain. Acute administration of SA4503 (1.0 mg/kg, p.o.) significantly increased DA and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the rat frontal cortex, but not in the other six regions, hippocampus, striatum, midbrain, cerebellum, medulla/pons and hypothalamus. The increase of cortical DA level elicited by SA4503 was fully reversed by N,N-dipropyl-2-(4-methoxy-3-(2-phenylethoxy)phenyl)ethylamine (NE-100) (0.25 mg/kg, p.o.), a putative 1 receptor antagonist. In addition, SA4503 (1.0 mg/kg, p.o.) showed an increase of cortical L-3,4-dihydroxyphenylalanine (L-DOPA) accumulation under the inhibition of dopa decarboxylase activity with m-hydrobenzylhydrazine (NSD-1015), suggesting that SA4503 has activated the cortical DA synthesis rate. These results suggest that the 1 receptor subtype plays an important role in the facilitation of cortical DA transmission. In addition, this phenomenon is partially involved in the augmentation of DA synthesis rate. 相似文献
987.
Lucidophyllous forest is the climax vegetation of the lowland and foothill areas of south-western Japan. We investigated the
myrmecofauna of lucidophyllous forests in different developmental stages in relation to the intensity of disturbance. The
less-disturbed lucidophyllous forests contained a greater variety of myrmecofauna. This pattern was explained by the condition
of the habitat. Richness in epigeal and/or hypogeal ant species is related to habitat structure, especially vegetation structure
expressed as summed vegetation cover, and the proportion of evergreen trees was a better predictor of ant species richness
than the depth of the soil organic layer. In disturbed stands, habitat conditions have deteriorated; subsequently, some silvicolous
ant species have disappeared. 相似文献
988.
Tetsuya Akamatsu Shigeo Daikoku Hideaki Nagamune Shigeru Yoshida Kenji Mori Akihiko Tsuji Y. Matsuda 《Histochemistry and cell biology》1997,108(2):95-103
PACE4 is a mammalian Kexin family protease that is involved in the maturation of precursor proteins. Four PACE4 isoforms
have been identified. We identified a novel PACE4 isoform, PACE4E, from a human cerebellum cDNA library, which possesses a
hydrophobic cluster in its C-terminus participating in membrane association. The size of PACE4E mRNA from adult rat brain
was estimated by Northern blotting to be 4.4 kb. In situ hybridization histochemistry revealed that the highest level of PACE4E
mRNA was expressed in the mitral cells of the adult rat olfactory bulb (OB). The OB is a unique sensory organ in that it has
a lifelong regenerating capacity and it affects brain development. We further analyzed the expression of PACE4E mRNA in the
developing olfactory system. On day 13.5 of gestation, PACE4E mRNA was expressed at high levels in the neuroepithelium of
the forebrain vesicle (FV), olfactory epithelium, and cells in the fiber bundles projecting to the FV. As development proceeded,
PACE4E mRNA was expressed in developing mitral cells but decreased in the olfactory epithelium. In the newborn, its expression
was confined to the mitral cells in both the main and accessory OB and in some periglomerular cells, as shown in adult rats.
The spatio-temporal expression of PACE4E suggests that it plays a role in the establishment and maintenance of the olfactory
receptor system.
Accepted: 15 April 1997 相似文献
989.
Masayuki Ezoe Toru Minami Yutaro Ogawa Shigeyuki Yagi Hiroyuki Nakazumi Tetsuya Matsuyama Kenji Wada Hiromichi Horinaka 《Photochemical & photobiological sciences》2005,4(8):641-646
Structurally controlled zinc porphyrin-anthracene dyads, syn-arranged 1 and anti-arranged 2, were newly synthesized employing a diarylurea linkage, and the excitation energy transfer (EET) from the anthracene to the zinc porphyrin chromophore was investigated by steady-state fluorescence emission spectroscopy as well as fluorescence lifetime measurement, especially focusing on the effect of the chromophoric orientation on the EET. In both of the dyads, intramolecular EET was facilitated upon excitation of the anthracene chromophore (lamda(ex)= 401 nm), and the zinc porphyrin S1-S0 emission (580-720 nm) was enhanced. The EET in the syn-arranged dyad 1 was more efficient than in the anti-arranged 2: the S1-S0 emission in 1 was 1.8 times larger than that in the zinc porphyrin reference compound 3, whereas that in 2 was enhanced by 1.6 times, compared to that in 3. In the fluorescence lifetime measurement, the quiet short-lived component assignable to the EET was observed for the dyads 1 and 2 beyond the analysis limit (<25 ps). The EET rate constants in the dyads 1 and 2 were estimated as not less than 4.0 x 10(10) s-1. However, in the case of 2, the residual long-lived component assigned to the anthracene emission was also observed at 425 nm. These results showed that the syn-arrangement of the zinc porphyrin and anthracene chromophores was more preferred for intramolecular EET to the anti-arrangement. 相似文献
990.
Atsuko Kushi Kiyotaka Akiyama Masato Noguchi Koji Edamura Takayuki Yoshida Hitoshi Sasai 《Experimental Animals》2004,53(5):437-443
Alpha-1-antitrypsin (alpha1-AT) is a member of the serine protease inhibitor family regulating numerous proteolytic processes. The genetic disorder, alpha1-AT deficiency, is well known as a cause of hereditary pulmonary emphysema and liver cirrhosis. To create an animal model of human alpha1-AT deficiency, we disrupted the major murine isoform PI2, which is similar to human alpha1-AT and is one of 7 alpha1-AT isoforms found in the mouse. The ability of the serum to inhibit the activities of human leukocyte elastase (HLE) and human chymotrypsin (CYT) was significantly lower in heterozygous mice (alpha1-AT/PI2 -/+) than wild-type (alpha1-AT/PI2 +/+) mice (73.2% vs. 100% for HLE and 67.8% vs.100% for CYT, respectively; P<0.05). The distribution of genotypes among F(2) progeny was not in accordance with Mendelian distribution (P<0.01), as the percentages of wild-type, heterozygotes and homozygotes were 47.8%, 37.3% and 14.9%, respectively. Thus, it is likely that impairment of the protease inhibitor had a critical effect on fetus development. The alpha1-AT/PI2 deficient mouse will be a useful animal model for elucidating the function of alpha1-AT in fetal development, studying the mechanisms of chronic inflammatory disease and evaluating therapeutic candidates for the treatment of inflammatory disease. 相似文献