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1.
Takabe Teruhiro; Ishikawa Hiroshi; Iwasaki Yukimoto; Inoue Hirofumi 《Plant & cell physiology》1989,30(1):85-90
Three types of PS I Chl-protein complex, PS I 180, PS I 65,and PS I 30, have been prepared and the kinetic properties ofthe transfer of electrons from plastocyanin to P700 in the PSI complexes with different sized antennae were examined. ThePS I 180 complex, which consists of 180 Chi per P700, showedthe almost same rate constant and effects of cations for thetransfer of electrons from plastocyanin to P700 as those obtainedwith PS I-enriched membrane fragments. The rate constant increasedwith the addition of low concentrations of monovalent and divalentcations, but decreased with high concentrations of cations.However, the rate was severely reduced in the case of the PSI 65 and PS I 30 complexes, and quite different effects of cationswere observed. Given the presence of additional 25- to 28-kDapolypeptides in the PS I 180 complex as compared to the PS I65 and PS I 30 complexes, we discuss a possible function forthese polypeptides in the regulation of the reaction betweenplastocyanin and P700.
1This work was supported in part by a Grant-in-Aid for ScientificResearch from the Ministry of Education, Science and Cultureof Japan. (Received May 27, 1988; Accepted November 7, 1988) 相似文献
2.
Hajime Otani Hitomi Otan Masao Morita Dipak K. Das 《Molecular and cellular biochemistry》1989,90(2):111-120
We investigated the effect of Ca2+ overload on the phospholipase C-catalyzed hydrolysis of phosphoinositides in the rat left ventricular papillary muscle. Ca2+ overload on the papillary muscle was induced by treatment with 0.3 mM ouabain in Ca2+-containing medium following either Ca2+-containing or Ca2+-free superfusion. The phosphoinositide breakdown was evaluated by determining accumulations of [3H]inositol phosphates ([3H]IPs) in the tissues prelabeled with [3H]inositol. Ca2+ repletion following Ca2+-free superfusion resulted in a rapid but small increase in resting tension that was not followed by contracture, nor was it associated with a significant increase in [3H]IPs accumulations. Treatment with ouabain following Ca2+-containing superfusion increased resting tension after a lag period of several minutes and produced contracture associated with an increase in [3H]IPs accumulations. The ouabain induced increases in resting tension, and accumulations of [3H]IPs were significantly potentiated by prior Ca2+-free superfusion instead of Ca2+-containing superfusion. There was a significant positive correlation between increases in resting tension and the phosphoinositide breakdown. The increased resting tension and the accumulations of [3H]IPs were not antagonized by treatments with prazosin plus atropine or indomethacin, but were abolished by superfusion with Ca2+-free buffer solution. Although the enhanced phospholipase C-catalyzed hydrolysis of phosphoinositides appears to be a consequence rather than a cause of increased intracellular Ca2+, such a biochemical change may provoke a positive feedback mechanism to develop the muscle contracture through the putative intracellular messenger action of inositol triphosphate and diacylglycerol.Abbreviations [3H]IPs
[3H]Inositol Phosphates
- IP
Inositol Phosphate
- IP2
Inositol Bisphosphate
- IP3
Inositol Trisphosphate
- PI
Phosphatidylinositol
- PI-4-P
Phosphatidylinositol-4-phosphate
- PI-4,5-P2
Phosphatidylinositol 4,5-bisphosphate
- PRZ
Prazosin
- ATR
Atropine
- INDO
Indomethacin
- min
Minutes 相似文献
3.
Masanori Ito Kazuhiro Yoshida Eikai Kyo Ayse Ayhan Hirofumi Nakayama Wataru Yasui Hisao Ito Eiichi Tahara 《Virchows Archiv. B, Cell pathology including molecular pathology》1990,59(1):173-178
We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), EGF
receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma
cell lines and 18 human colorectal carcinomas.
In surgically resected specimens of the 18 colorectal tumors, TGF-α, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various
levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly,
EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically
in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics.
All the colorectal carcinoma cell lines expressed TGF-α mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production
of TGF-α protein by DLD-1 and CoLo320DM cells was confirmed by TGF-α specific monoclonal antibody binding assay. The spontaneous3H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-α monoclonal antibody. PDGFA and PDGFB mRNA were also expressed
in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express
multi-loops of growth factors and that TGF-α produced by tumor cells functions as an autocrine growth factor in human colonic
carcinoma. 相似文献
4.
Summary In colchicine-pretreated cells of sympathetic ganglia, intensely NPY-immunoreactive material was localized within vacuoles and vesicles of the disorganized, widely dispersed Golgi apparatus. Intensely positive large granular vesicles, which are known to be one of major storage sites of various peptides in the autonomic nerve endings, were essentially unobserved in the perikaryal cytoplasm. The present finding provides evidence that one pool of NPY-like immunoreactivity is localized in the Golgi apparatus of colchicine-pretreated as well as normal sympathetic ganglion cells. It is also clear that visualization of NPY-immunoreactive somata by colchicine-pretreatment in the sympathetic ganglia is due to the accumulation of the neuropeptide in the disorganized Golgi stacks instead of increased amount of the large granular vesicles containing NPY. 相似文献
5.
Akihiro Hara Hiroyuki Hashimoto Hirofumi Morota Hiroshi Harada Hirofumi Uchimiya 《Journal of plant research》1988,101(2):131-140
Tobacco mesophyll protoplasts were treated with plasmids, pCT2 (17.1 kbp) or pCT2T3 (18.3 kbp), which contained a chimeric aminoglycoside phosphotransferase II (APH(3′)II) gene and an intact nopaline synthase gene. Expression of two marker enzymes, APH(3′)II and nopaline synthase, were analyzed in transformed plants. Four out of 16 transformants obtained by pCT2T3 possessed both enzymes. Upon self-pollination, the progeny of one of transformants (T2) segregated to 153∶4 in terms of resistant and susceptible character to kanamycin, suggesting insertion of foreign genes into three independent chromosomes. The kanamycin resistant character in the rest of transformants showed 3∶1 segregation. DNA blot analysis of the T2 transformant and progenies indicated the presence of two marker genes. 相似文献
6.
Komeda Yoshibumi; Yamashita Hirofumi; Sato Naoki; Tsukaya Hirokazu; Naito Satoshi 《Plant & cell physiology》1991,32(6):737-743
The 5'-upstream region (2.4 kb) of the gene for phytochromeI from Pisum sativum (phyl) was fused to the uidA gene fromEscherichia coli that encodes ß-glucuronidase (GUS).The resulting PHY-GUS fusion was introduced into Petunia hybridaand was used as a reporter of the expression of the phyI genewhich was recognized by GUS activity. The PHY-GUS fusion wasexpressed at a relatively high level when transgenic plantswere grown in the dark, while leaves and stems of light-grownplants showed background activity. Flowers of light-grown plantswere shown to have significant levels of GUS activity but rootsdid not have such activity. When light-grown transgenic plantswere transferred to the dark, they expressed the activity atlevels that corresponded to those of dark-grown plants. Lighttreatment prior to growth in darkness revealed red/far-red reversibilityof recovery of the activity. Thus, the 2.4-kb fragment fromthe 5' region of the phyI gene carries the information necessaryfor the light-repressible autoregulation. (Received March 30, 1991; Accepted May 20, 1991) 相似文献
7.
Shiraishi Tomonori; Araki Miwa; Yoshioka Hirofumi; Kobayashi Issei; Yamada Tetsuji; Ichinose Yuki; Kunoh Hitoshi; Oku Hachiro 《Plant & cell physiology》1991,32(7):1067-1075
A pathogenic fungus of pea, Mycosphaerella pinodes, secretesa so-called "suppressor" in its pycnospore germination fluid.The suppressor blocks the defense responses and induces localsusceptibility (accessibility) in pea plants to agents thatare not pathogenic in pea. The suppressor nonspecifically inhibitsthe ATPase activity in plasma membranes prepared from pea, soybean,kidney bean, cowpea and barley plants. However, cytochemicalstudies by electron microscopy indicate that the suppressorspecifically inhibits the ATPase in pea cell membranes, butnot in those of four other plant species tested. That is, thespecificity of the suppressor appears at the cell and/or tissuelevel, but is not evident in vitro. Furthermore, the inhibitoryeffect of the suppressor is temporary because the ATPase activityrecovers 9 h after the treatment. A similar effect was observedafter inoculation with M. pinodes but not with a nonpathogenof pea, M. ligulicola. The role of the suppressor in host-parasitespecificity is discussed. (Received April 9, 1991; Accepted August 6, 1991) 相似文献
8.
In vitro binding of nuclear proteins from wheat germ to the5'-upstream region of the rolC gene of Ri plasmid was investigated.The specific DNA sequences interacting with proteins were detectedby DNase I footprinting. (Received October 8, 1990; Accepted November 30, 1990) 相似文献
9.
10.
Hirofumi Ogawa Yoshihisa Ishiguro Motoji Fujioka 《Archives of biochemistry and biophysics》1983,226(1):265-275
Guanidoacetate methyltransferase (EC 2.1.1.2) has been purified about 800-fold from rat liver. The purified preparation shows a single protein band on polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. The molecular weight of the enzyme is estimated to be 25,000 and 26,000 by Sephadex gel molecular-exclusion chromatography and by electrophoresis in polyacrylamide gradient gel, respectively. The sodium dodecyl sulfate-denatured enzyme also has a molecular weight of 26,000; thus, the enzyme is a monomeric protein. Guanidoacetate methyltransferase as isolated is catalytically inactive, but is readily reactivated by incubation with a thiol. The reactivated enzyme, which contains 3 mol of sulfhydryl groups/mol of enzyme, is again inactivated by oxidized glutathione. This inactivation is accompanied by the disappearance of two sulfhydryl residues. The relationship between the loss of enzyme activity and the number of residues disappeared indicates that the integrity of these sulfhydryl residues is critical for activity. The oxidized enzyme fails to bind the substrate S-adenosylmethionine as evidenced by the equilibrium dialysis study. Alkylation of the nonoxidizable sulfhydryl by N-ethylmaleimide shows that this residue is also essential for activity. UV absorption, fluorescence, and CD spectra show no difference between the reduced and oxidized enzymes, but the former is more susceptible to proteolytic attack by trypsin. The enzyme has an isoelectric pH of 5.3, and is most active at pH 9.0. From the CD spectrum, an α helix content of 15% is calculated. The Km values for guanidoacetate and S-adenosylmethionine are 97.5 and 6.73 μm, respectively, at pH 8.0 and 37 °C. 相似文献