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891.
Resistance to Apo2 ligand (Apo2L)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis and constitutive expression of Apo2L/TRAIL in human T-cell leukemia virus type 1-infected T-cell lines
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Matsuda T Almasan A Tomita M Uchihara JN Masuda M Ohshiro K Takasu N Yagita H Ohta T Mori N 《Journal of virology》2005,79(3):1367-1378
Adult T-cell leukemia (ATL), a CD4+-T-cell malignancy caused by human T-cell leukemia virus type 1 (HTLV-1), is difficult to cure, and novel treatments are urgently needed. Apo2 ligand (Apo2L; also tumor necrosis factor-related apoptosis-inducing ligand [TRAIL]) has been implicated in antitumor therapy. We found that HTLV-1-infected T-cell lines and primary ATL cells were more resistant to Apo2L-induced apoptosis than uninfected cells. Interestingly, HTLV-1-infected T-cell lines and primary ATL cells constitutively expressed Apo2L mRNA. Inducible expression of the viral oncoprotein Tax in a T-cell line up-regulated Apo2L mRNA. Analysis of the Apo2L promoter revealed that this gene is activated by Tax via the activation of NF-kappaB. The sensitivity to Apo2L was not correlated with expression levels of Apo2L receptors, intracellular regulators of apoptosis (FLICE-inhibitory protein and active Akt). NF-kappaB plays a crucial role in the pathogenesis and survival of ATL cells. The resistance to Apo2L-induced apoptosis was reversed by N-acetyl-L-leucinyl-L-leucinyl-lLnorleucinal (LLnL), an NF-kappaB inhibitor. LLnL significantly induced the Apo2L receptors DR4 and DR5. Our results suggest that the constitutive activation of NF-kappaB is essential for Apo2L gene induction and protection against Apo2L-induced apoptosis and that suppression of NF-kappaB may be a useful adjunct in clinical use of Apo2L against ATL. 相似文献
892.
Importance of both the coding and the segment-specific noncoding regions of the influenza A virus NS segment for its efficient incorporation into virions 总被引:7,自引:0,他引:7
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Fujii K Fujii Y Noda T Muramoto Y Watanabe T Takada A Goto H Horimoto T Kawaoka Y 《Journal of virology》2005,79(6):3766-3774
The genome of influenza A virus consists of eight single-strand negative-sense RNA segments, each comprised of a coding region and a noncoding region. The noncoding region of the NS segment is thought to provide the signal for packaging; however, we recently showed that the coding regions located at both ends of the hemagglutinin and neuraminidase segments were important for their incorporation into virions. In an effort to improve our understanding of the mechanism of influenza virus genome packaging, we sought to identify the regions of NS viral RNA (vRNA) that are required for its efficient incorporation into virions. Deletion analysis showed that the first 30 nucleotides of the 3' coding region are critical for efficient NS vRNA incorporation and that deletion of the 3' segment-specific noncoding region drastically reduces NS vRNA incorporation into virions. Furthermore, silent mutations in the first 30 nucleotides of the 3' NS coding region reduced the incorporation efficiency of the NS segment and affected virus replication. These results suggested that segment-specific noncoding regions together with adjacent coding regions (especially at the 3' end) form a structure that is required for efficient influenza A virus vRNA packaging. 相似文献
893.
Suppression of thymic lymphoma induction by life-long low-dose-rate irradiation accompanied by immune activation in C57BL/6 mice 总被引:6,自引:0,他引:6
The induction of thymic lymphomas by whole-body X irradiation with four doses of 1.8 Gy (total dose: 7.2 Gy) in C57BL/6 mice was suppressed from a high frequency (90%) to 63% by preirradiation with 0.075 Gy X rays given 6 h before each 1.8-Gy irradiation. This level was further suppressed to 43% by continuous whole-body irradiation with 137Cs gamma rays at a low dose rate of 1.2 mGy/h for 450 days, starting 35 days before the challenging irradiation. Continuous irradiation at 1.2 mGy/h resulting in a total dose of 7.2 Gy over 258 days yielded no thymic lymphomas, indicating that this low-dose-rate radiation does not induce these tumors. Further continuous irradiation up to 450 days (total dose: 12.6 Gy) produced no tumors. Continuously irradiated mice showed no loss of hair and a greater body weight than unirradiated controls. Immune activities of the mice, as measured by the numbers of CD4+ T cells, CD40+ B cells, and antibody-producing cells in the spleen after immunization with sheep red blood cells, were significantly increased by continuous 1.2-mGy/h irradiation alone. These results indicate the presence of an adaptive response in tumor induction, the involvement of radiation-induced immune activation in tumor suppression, and a large dose and dose-rate effectiveness factor (DDREF) for tumor induction with extremely low-dose-rate radiation. 相似文献
894.
12-oxo-phytodienoic acid triggers expression of a distinct set of genes and plays a role in wound-induced gene expression in Arabidopsis
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895.
896.
Mahakkanukrauh P Tohno S Tohno Y Azuma C Ongkana N Moriwake Y Minami T 《Biological trace element research》2005,106(3):219-229
To examine whether there were differences between reces in regard to age-related changes of elements and the relationships
among elements in the arteries, the authors investigated both the renal arteries of Thai and Japanese. The Thai subjects consisted
of 27 men and 11 women, ranging in age from 27 to 88 yr, whereas the Japanese subjects consisted of 19 men and 26 women, ranging
in age from 61 to 99 yr. After the ordinary dissections at Chiang Mai University and Nara Medical University were completed,
the bilateral renal arteries were resected and the element contents were determined by inductively coupled plasma-atomic emission
spectrometry. In the Thai, a slight accumulation of calcium and phosphorus occurred in the fifties, but thereafter headly
increased. In contrast, in the Japanese, an accumulation of calcium and phosphorus began to occur in the seventies and increased
markedly in the eighties. The result reveraled that a higher accumulation of calcium and phosphorus occurred in the renal
arteries of the Japanese in old age compared with those of the Thai. Regarding the relationships among elements, extremely
or very significant direct correlations were found among the contents of calcium, phosphorus, magnesium, and sodium in both
the renal arteries of the Thai and Japanese, except for magnesium and sodium contents in the renal arteries of the Thai. 相似文献
897.
A growing body of evidence indicates that the mesolimbic dopaminergic (DAergic) pathway projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) play a critical role in the initiation of psychological dependence on morphine. As well as DAergic system, the involvement of non-DAergic neurotransmitter and neuromodulator systems in rewarding effects induced by morphine has been recently documented. We previously demonstrated that the morphine-induced rewarding effect was dramatically suppressed by co-treatment with NMDA receptor antagonists, such as dizocilpine (MK-801), ketamine and ifenprodil. Therefore, we propose here that inhibiting the N-methyl-D-aspartate (NMDA) receptor and its associated protein kinase in the N.Acc. is useful for the treatment for psychological dependence on morphine. The following review provides a summary of recent our findings regarding the role of NMDA receptor and its associated protein kinase in the development of psychological dependence on morphine. 相似文献
898.
899.
Tada Y Kusaka K Betsuyaku S Shinogi T Sakamoto M Ohura Y Hata S Mori T Tosa Y Mayama S 《Plant & cell physiology》2005,46(11):1787-1798
The host-selective toxin victorin is produced by Cochliobolus victoriae, the causal agent of victoria blight of oats. Victorin has been shown to bind to the P protein of the glycine decarboxylase complex (GDC) in mitochondria, and induce defense-related responses such as phytoalexin synthesis, extracellular alkalization and programmed cell death. However, evidence demonstrating that the GDC plays a critical role in the onset of cell death is still lacking, and the role of defense-like responses in the pathogenicity has yet to be elucidated. Here, cytofluorimetric analyses, using the fluorescein (VicFluor) or bovine serum albumin-fluorescein derivative of victorin (VicBSA), demonstrated that victorin-induced cell death occurs before these conjugates traverse the plasma membrane. As with native victorin, VicBSA clearly elicits apoptosis-like cell death, production of phytoalexin, extracellular alkalization, and generation of nitric oxide and reactive oxygen intermediates. These results suggest that the initial recognition of victorin takes place on the cell surface, not in mitochondria, and leads to the activation of a battery of victorin-induced responses. Pharmacological studies showed that extracellular alkalization is the essential regulator for both victorin- and VicBSA-induced cellular responses. We propose a model where victorin may kill the host cell by activating an HR-like response, independent of the binding to the GDC, through ion fluxes across the plasma membrane. 相似文献
900.
Ishikawa S Ohtsuki S Tomita K Arihara K Itoh M 《Biological trace element research》2005,105(1-3):249-256
It is known that nonheme iron accumulates and free radicals are generated in skin exposed to ultraviolet (UV) light. Iron
ions have a role in skin photodamage by participating in the formation of reactive oxygen species. In this study, we evaluated
the effect of egg yolk phosvitin on UV-light-induced oxidative stress. Mouse dorsal skin homogenate was exposed to UVA light
in the presence or absence of ferric nitrilotriacetate, (FeNTA). Lipid peroxidation was determined by measuring thiobarbituric
acid-reactive substances (TBARS). The TBARS concentration increased with increasing FeNTA concentration and UV-light-exposure
time. In the presence of FeNTA, phosvitin more effectively inhibited in vitro lipid peroxidation than did bovine serum albumin.
According to results of electron spin resonance studies using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent, phosvitin suppressed the formation of hydroxyl radicals. These results suggest that
UV-light-induced oxidative stress can be reduced by phosvitin. 相似文献