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71.
Nishiyama Yoshitaka; Kovcs Eszter; Lee Chin Bum; Hayashi Hidenori; Watanabe Tadashi; Murata Norio 《Plant & cell physiology》1993,34(2):337-343
Photosynthetic adaptation to high temperature was investigatedin intact cells and isolated thylakoid membranes of the cyanobacterium,Synechococcus PCC7002. In intact cells, the thermal stabilityof photosynthesis and photosystem 2-mediated electron transportfrom H2O to 1,4-benzoquinone changed in concert with growthtemperature. The photosystem 2-mediated electron transport fromH2O to phenyl-1,4-benzoquinone showed greater thermal stabilityin thylakoid membranes isolated from cells which had adaptedto high temperature than in those from non-adapted cells. Enhancedthermal stability was also observed in the thylakoid membranesin the transport of electrons from H2O to 2,6-dichlorophenolindophenolbut not in the transport of electrons from diphenylcarbazideto 2,6-dichlorophenolindophenol. These observations suggestthat oxygen-evolving sites acquire enhanced thermal stability,and that factors which are responsible for thermal stabilityremain in isolated thylakoid membranes. (Received October 30, 1992; Accepted December 18, 1992) 相似文献
72.
Yoshiharu Inoue Yoshitaka Iba Hiroshi Yano Kousaku Murata Akira Kimura 《Applied microbiology and biotechnology》1993,38(4):473-477
A high expression system of the -glutamylcysteine synthetase gene (gshl) of Escherichia coli B was constructed, and rapid purification of GSH-I was performed. The active site of GSH-I was analysed by chemical modification, and Lys, Arg and His residues seemed to be involved in the active site of the enzyme. Among them, His residues were substituted to Ala by site-directed mutagenesis, and His-150 was found to be essential for the activity of GSH-I.
Correspondence to: A. Kimura 相似文献
73.
Fragment X (LMrFX) was obtained as low molecular weight preparations from a late stage 2 plasmin digest of human fibrinogen. The thrombin-treated LMrFX preparations, which resulted in impaired polymerization, were further subfractionated into polymerized and non-polymerized components. The fractions were examined by SDS-PAGE and immunochemical methods. In polymerized fractions, more peptide bands were observed on SDS-PAGE in the reduced state than in non-polymerized fractions. Both fractions contained a similar number of internal cleavages in the A, Bβ and γ chains, which are linked by disulfide bonds. Thus, the partial deficiencies in polymerization sites of the carboxy terminal region of the γ chain and the amino terminal portions of the Bβ chain, as well as internal cleavage, were considered to participate in the impairment of the thrombin-induced polymerization of LMrFX. 相似文献
74.
M Murata S Takahashi Y Shirai S Kagiwada R Hishida S Ohnishi 《Biophysical journal》1993,64(3):724-734
We have synthesized five amphiphilic anionic peptides derived from E5 peptide [Murata, M., Takahashi, S., Kagiwada, S., Suzuki, A., Ohnishi, S. 1992. Biochemistry 31:1986-1992. E5NN and E5CC are duplications of the N-terminal and the C-terminal halves of E5, respectively, and E5CN is an inversion of the N- and the C-terminal halves. E5P contains a Pro residue in the center of E5 and E8 has 8 Glu residues and 9 Leu residues. We studied fusion of dioleoylphosphatidylcholine (DOPC) large unilamellar vesicles assayed by fluorescent probes. The peptides formed alpha-helical structure with different degrees; E5NN, E5CN, and E8 with high helical content and E5CC and E5P with low helical content. These peptides bound to DOPC vesicles at acidic pH in proportion to the helical content of peptide. The peptides caused leakage of DOPC vesicles which increased with decreasing pH. The leakage was also proportional to the helicity of peptide. Highly helical peptides E5NN, E5CN, and E8 caused hemolysis at acidic pH but not at neutral pH. The fusion activity was also dependent on the helicity of peptides. In fusion induced by an equimolar mixture of E5 analogues and K5 at neutral pH, E8, E5NN, and E5CN were most active but E5CC did not cause fusion. In fusion induced by E5-analogue peptides alone, E5CN was active at acidic pH but not at neutral pH. Other peptides did not cause fusion. Amphiphilic peptides also appear to require other factors to cause fusion. 相似文献
75.
Yoshio Oka Tetsuro Kobayashi Shoichi Fujita Nariaki Matsuura Shigeru Okamoto Hideki Asakawa Atsuo Murata Takesada Mori 《In vitro cellular & developmental biology. Animal》1993,29(7):537-542
Summary A human anaplastic thyroid cancer cell line K-119, derived from a 77-yr-old woman who had developed marked neutrophilia and
underwent surgery for anaplastic thyroid cancer, has been established. The spindlelike and polygonal cells in shape are stably
proliferating since the beginning of its culture 2 yr ago. The cells grow rapidly and the population doubling time is 26 h.
The chromosomes show many abnormalities and many marker chromosomes have been observed. Heterotransplantation of the cells
into nude mice has resulted in the formation of tumors that are histologically interpreted as anaplastic cancer. The most
noteworthy characteristics of the cell line are the many Ki-67-positive cells (86.3%) and that the cell line spontaneously
secretes granulocyte colony-stimulating factor (G-CSF) and releases increased amounts of G-CSF in response to the stimulation
of tumor necrosis factor, interleukin 1α, and interleukin 1β. The conditioned medium obtained from K-119 cells contains an
autocrine factor stimulating the proliferation of themselves. 相似文献
76.
Oxygen uptake measurements have shown that pressurized gas transport, resulting from the physical effect of thermo-osmosis
of gases, improves oxygen supply to the roots of the seedlings in two alder speciesAlnus japonica (Thunb.) Steud. andAlnus hirsuta (Spach) Rupr., which are both native in Japan. When gas transport conditions were established by irradiation of the tree
stems the internal aeration was increased to a level nearly equal to the oxygen demand of the root system in leafless seedlings
ofA. hirsuta, but was higher inA. japonica so that excess oxygen was excreted into the environment. An increase of superoxide dismutase (SOD) activity, which protects
plants from toxic oxygen radicals and post-anoxic injury, has been observed in root tissues ofA. japonica when the seedlings were flooded for 3 days. The increase of SOD activity, in concert with high gas transport rates, may enable
this tree species to grow in wet sites characterized by low oxygen partial pressure in the soil and by varying water tables.
A less effective gas transport, flood-induced reduction of SOD activity in root tissues, and reduced height growth in waterlogged
soil may be responsible for the fact thatA. hirsuta is unable to inhabit wettland sites. 相似文献
77.
Organization of microtubules (MTs) in relation to the behavior of nuclei was examined in dividing binucleate cells ofAdiantum capillus-veneris L. To induce binucleate cells, caffeine, an inhibitor of formation of the cell plate, was applied at 4 mM to synchronously
dividing protonemal cells during cytokinesis (Murata and Wada 1993). Formation of the preprophase band (PPB) during the next
cell cycle was examined in non-centrifuged and centrifuged cells. The two nuclei were separated or associated with one another
in both non-centrifuged and centrifuged cells, although the location of the nuclei in the cylindrical protonemal cells was
different (Murata and Wada 1993). Irrespective of centrifugation, a single PPB was formed around the nuclei in cells with
associated nuclei. Two PPBs were formed in cells with separated nuclei in centrifuged cells. Patterns of mitosis and cytokinesis
varied, depending on the location of the PPB and the distribution of the nuclei. The role of the nucleus in formation of the
PPB is discussed. 相似文献
78.
79.
Cosmid and plasmid clones containing 11 kb, or more, of genomic DNA sequences were mapped with high efficiencies using fluorescence in situ hybridization (FISH) to mitotic metaphase chromosomes prepared from floral tissues of Arabidopsis thaliana. The chromosomal locations were correlated with the map positions determined by RFLP (restriction fragment length polymorphism) analyses. Almost no signals were detected on the chromosomes of root meristematic tissues when FISH was performed with the same clones as probes. This discrepancy in efficiency of detection is possibly caused by the differences in chromatin structure between the root meristematic tissues and the floral tissues. 相似文献
80.
Nishijima K Hisatsune T Kato H Kohyama M Kakehi M Hachimura S Kaminogawa S 《Cytotechnology》1997,25(1-3):89-100
Feeding of a whole casein diet, which abolished the αs1-casein-specific proliferation and IFN-γ productivity of CD4+ T cells, did not affect the proliferative response of CD8+ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity,
as well as IFN-γ production. To assess the characteristics of the CD8+ T cells, we established αs1-casein-specific CD8+ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10,
and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced
considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8+ T cells in oral tolerance is discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献