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991.
A McKnight R A Weiss C Shotton Y Takeuchi H Hoshino P R Clapham 《Journal of virology》1995,69(5):3167-3170
The V3 loop of human immunodeficiency virus type 1 is both a determinant of viral cell tropism and a target for neutralizing antibodies. This relationship was investigated. Selection of a dual-tropic (T cells and macrophages) virus to replicate in CD4+ brain cells results in loss of macrophage tropism and of neutralization by an anti-V3 loop monoclonal antibody. Moreover, selection of the brain-selected variant to escape from V3 loop-specific neutralizing monoclonal antibodies results in the reduction or loss of brain cell tropism and the reacquisition of macrophage tropism. These data may indicate that the antigenic diversification of human immunodeficiency virus type 1 apparent after seroconversion can be selected either by immune responses or by colonization of new cell types. 相似文献
992.
A γ-pyronyl triterpenoid saponin termed chromosaponin 1 (CSI), a conjugate of soyasaponin I and γ-pyrone, was found at 3 mM to stimulate the growth of lettuce root ( Lactuca sativa L. ev. Grand Rapids) to about 190% of the control. Since CSI is an amphipathic reductant, the stimulating effect of this saponin was compared with other reductants and other surface-active compounds. Trolox (2-carboxy-2.5.7.8-tetraamethyl-6-chromanol). another amphipathic reductant, also stimulated root growth, while other hydrophilic reductants including ascorbate. NADPH, NADH and glutathione did not. Some surfactants promoted root growth but their stimulating effects were smaller than the optimum effect of CSI. These results suggest a possible Function of CSI as an amphipathic reductant in root growth regulation. 相似文献
993.
Effects of hypergravity on the elongation and morphology of protonemata of Adiantum capillus-veneris
Hirokazu Kasahara Kazumi Yanagiya Yuichi Takeuchi Masamichi Yamashita Mitsuhiro Yamada 《Physiologia plantarum》1995,93(2):352-356
Elongation growth of protonemata of Adiantum capillus-veneris , which can be controlled by light irradiation, was examined under acropetal and basipetal hypergravity conditions (from -13 to +20 g ) using a newly developed centrifugation equipment. Elongation of the protonemata under red light was inhibited by basipetal hypergravity at more than +15 g but was promoted by acropetal hypergravity from -5 to -8 g . Division of the protonemal cells that was induced by white light was inhibited under basipetal hypergravity at +20 g but was unaffected under acropetal hypergravity at -15 g . Upon exposure to continuous red light for 7 to 8 days, most of the protonemata grew as filamentous cells in the absence of a change in the normal gravitational force (control), but more than half of the protonemal cells were abnormal in terms of shape when maintained under hypergravity at +20 g . 相似文献
994.
The elongation growth of the hypocotyls of radish and cucumber seedlings was examined under hypergravity in a newly developed centrifuge (Kasahara et al. 1995). The effects of hypergravity on elongation growth differed between the two species. The rate of elongation of radish hypocotyls was reduced under basipetal hypergravity (H+2O g) but not under acropetal hypergravity (H-13 g), as compared to growth under the control conditions (C+1 g and C-1 g). In cucumber hypocotyls, elongation growth was inhibited not only by basipetal but also by acropetal hypergravity. Under these conditions, the reduction in the elongation growth of both radish and cucumber hypocotyls was accompanied by an increase in their thickness. Although no distinct differences in relative composition of neutral sugars were found, the amounts of cell-wall components (pectic substances, hemicelluloses and cellulose) per unit length of hypocotyls were increased by exposure to hypergravity. 相似文献
995.
Mitsuo Satoh Hiromasa Miyaji Tatsunari Nishi Tamio Mizukami Seiji Sato Seiga Itoh Mamoru Hasegawa 《Cytotechnology》1995,18(3):167-172
We have compared the level of expression of several enhancer/promoters in human lymphoblastoid Namalwa KJM-1 cells when fused to a common reporter gene. A cassette containing the pro-urokinase (pro-UK) coding sequence followed by the rabbit -globin and simian virus 40 (SV40) 3 nontranslated region was used for evaluation of the enhancer activity. Cells containing Moloney murine leukemia virus (Mo-MuLV) promoter had an average of 10–20 fold higher expression levels of pro-UK than those containing other promoters, such as SV40 early gene promoter, human cytomegalovirus (hCMV) major immediate-early gene promoter, Rous sarcoma virus (RSV) promoter and chicken -actin gene promoter. The expression level of pro-UK under the control of Mo-MuLV promoter was 2–3 g/106 cells/day and was constant for more than 6 months. Furthermore, the production of a high producer clone, obtained by using dhfr gene coamplification, reached 30–40 g/106 cells/day. Thus, Mo-MuLV promoter showed the desired characteristics for efficient expression of foreign genes in Namalwa KJM-1 cells.Abbreviations dhfr
dihydrofolate reductase
- G-CSF
granulocyte colony-stimulating factor
- hCMV
human cytomegalovirus
- LTR
long terminal repeat
- Mo-MuLV
Moloney murine leukemia virus
- MTX
methotrexate
- pro-UK
pro-urokinase
- RSV
Rous sarcoma virus
- SV40
simian virus 40
- T3
triiodo-thyronine
- TRE
thyroid-hormone responsive element 相似文献
996.
Hitoshi Komatsuzawa Motoyuki Sugai Seiji Nakashima Hidekazu Suginaka 《Microbiology and immunology》1995,39(8):629-633
Profiles of cell-associated bacteriolytic activities and those in the culture supernatant of Staphylococcus aureus FDA209P at various stages of growth were analyzed using sodium dodecyl sulfate-polyacrylamide gels containing Micrococcus luteus or S. aureus. In the logarithmic growth phase, the cell-associated bacteriolytic activities extracted with Triton X-100 contained a number of bacteriolytic proteins, the profiles of which were similar to those we reported elsewhere (Sugai, M., Akiyama, T., Komatsuzawa, H., Miyake, Y., and Suginaka, H.(1990) J. Bacteriol., 172, 6494-6498). The proteins include P1, P2, P7, P9, PX, P13, P18 and other minor components. At the stationary growth phase, the bacteriolytic band-profile of the Triton X-100 extract changed dramatically. P1, P7 and P9 disappeared, and the other minor bands had markedly decreased band intensities. On the other hand, P2, PX, P13, and P18 retained their band intensities during the stationary growth phase. The band intensities of P7, P13, PX, and P18 increased in the supernatant during the logarithmic growth phase. These results indicated that the bacteriolytic band-profile changes during growth. 相似文献
997.
Yoshihiro Masuda Seiji Mita Kiyoshi Sakamoto Takatoshi Ishiko Michio Ogawa 《Cancer immunology, immunotherapy : CII》1995,41(6):325-330
To investigate the influence of tumor producing interleukin-5 (IL-5) on growth kinetics of tumors, we transduced the murine IL-5 gene into murine colon C26 tumor cells. Two IL-5-secreting clones, low-level IL-5 producer C26-8B and high-level IL-5 producer C26-6F, were established. Both tumors, C26-6F and C26-8B, grew more slowly than the mock C26 tumor, although the in vitro growth rate of these IL-5 transfectants was much the same as that of the mock C26 cells. There was a significantly decreased number of colonies in the lung of mice given C26-6F or C26-8B tumors i.v. than in mice given mock C26 tumors i.v. Moreover, in mice given C26-6F cells i.v., a smaller number of tumor colonies in the lung was observed, as compared to the case with C26-6B cells. While the growth rate of C26-8B tumors in mice treated with anti-IL-5 mAb was more rapid than that seen in control mAb-treated mice, growth of C26-6F tumors in anti-IL-5-mAb-treated mice was slightly more rapid compared to findings in control mAb-treated mice. The isotypematched mAb did not alter the in vitro growth of mock-C26 cells or of the IL-5-gene-modified C26 cells. Growth of IL-5-secreting C26 tumors transplanted in nude mice was also inhibited. These results suggest that tumor-producing IL-5 inhibits growth of colon tumors mediated through T-cell-independent protective mechanisms of the host. 相似文献
998.
Seiji Kudoh Qiu Wang Oscar F. Hidalgo Pat Rayman Raymond R. Tubbs Mark G. Edinger Ronald Bukowski James H. Finke 《Cancer immunology, immunotherapy : CII》1995,41(3):175-184
T cells infiltrating (T-TIL) B cell non-Hodgkin's lymphomas (NHL) are thought to represent a local host response to the tumor. However, tumor progression in the presence of this T cell infiltrate suggests that the T-TIL may be functionally impaired. To address this issue we determined whether response to stimulation of T-TIL from 25 patients with NHL through the T cell receptor (TCR/CD3) and the interleukin-2 (IL-2) receptor (IL-2R) was intact, since activation of these receptors is important for proliferation and cytokine production. Our results demonstrate defects in response to stimulation via TCR/CD3 and the IL-2R in T-TIL cells from patients with NHL that were not observed with T cells from the peripheral blood. T-TIL showed minimal proliferation to anti-CD3 and only modest proliferation to IL-2 alone or when combined with anti-CD3. Moreover, cytokine production in T-TIL was impaired since stimulation through the TCR/CD3 complex did not induce mRNA for interferon (IFN), IL-2, IL-4 or IL-10. The functional unresponsiveness of these cells may be linked to altered signalling through the TCR/CD3 since an abnormal tyrosine phosphorylation pattern was detected in T-TIL after stimulation with anti-CD3. 相似文献
999.
Seiji Ichida Tetsuyuki Wada Takafumi Akimoto Yasunari Kasamatsu Miki Tahara Kiyo Hasimoto 《Neurochemical research》1995,20(4):467-473
Characteristic of [125I]-conotoxin (-CgTX) labeling using bifunctional cross linker (dithio bis[succinimidyl propionate]: DSP) was systematically investigated in crude membranes from chick whole brain. [125I]-CgTX specifically labeled 216 kDa as a main and 236 kDa as a minor bands in the crude membranes under non-reduced condition, but not labeled under reduced condition. We investigated the effect of various Ca channel antagonists on [125I]-CgTX labeling with DSP in detail, and found that there is a strong correlation between the effects of Ca channel antagonists on [125I]-CgTX labeling of the 216 kDa band and specific [125I]-CgTX binding. These results suggest that labeling of the 216 kDa band under non-reduced condition with [125I]-CgTX using DSP involves the specific binding sites of [125I]-CgTX, perhaps including one of the neuronal N-type Ca channel subunits in the crude membranes. 相似文献
1000.
Yasutomo Takeuchi Yumi Omigawa Masaru Ogasawara Koichi Yoneyama Makoto Konnai A. Douglas Worsham 《Plant Growth Regulation》1995,16(2):153-160
Brassinolide [2, 3, 22R,23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5--cholestan-6-one] and its related compounds, brassinosteroids, applied at the early stages of conditioning shortened the conditioning period required before clover broomrape seeds would germinate after exposure to germination stimulants, such as dl-strigol and natural stimulants from red clover (Trifolium pratense L.) root exudate. Brassinosteroids applied after conditioning increased the rate of the seed germination induced by these stimulants. The inhibitory effect of light on seed germination when it was induced by dl-strigol could be overcome by brassinosteroids. Brassinosteroids also eliminated the inhibitory effects of light and dl-strigol applied at the early stages of conditioning. GA3 was also effective in causing seed conditioning and increased the rate of the germination induced by these stimulants. There was a relationship between brassinosteroids and GA3 in many of the experiments conducted. These findings may have practical implications in increasing the effectiveness of applying germination stimulants in the field to soils for suicidal germination of broomrape seeds. 相似文献