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81.
82.
Complete genome structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids. 总被引:5,自引:0,他引:5
Yasukazu Nakamura Takakazu Kaneko Shusei Sato Mamoru Mimuro Hideaki Miyashita Tohru Tsuchiya Shigemi Sasamoto Akiko Watanabe Kumiko Kawashima Yoshie Kishida Chiaki Kiyokawa Mitsuyo Kohara Midori Matsumoto Ai Matsuno Naomi Nakazaki Sayaka Shimpo Chie Takeuchi Manabu Yamada Satoshi Tabata 《DNA research》2003,10(4):137-145
83.
We examined energy transfer dynamics in phycobilisomes (PBSs) of cyanobacteria in relation to the morphology and pigment compositions of PBSs. We used Gloeobacter violaceus PCC 7421 and measured time-resolved fluorescence spectra in three types of samples, i.e., intact cells, PBSs, and rod assemblies separated from cores. Fremyella diplosiphon, a cyanobacterial species well known for its complementary chromatic adaptation, was used for comparison after growing under red or green light. Spectral data were analyzed by the fluorescence decay-associated spectra with components common in lifetimes with a time resolution of 3 ps/channel and a spectral resolution of 2 nm/channel. This ensured a higher resolution of the energy transfer kinetics than those obtained by global analysis with fewer sampling intervals. We resolved four spectral components in phycoerythrin (PE), three in phycocyanin (PC), two in allophycocyanin, and two in photosystem II. The bundle-like PBSs of G. violaceus showed multiple energy transfer pathways; fast ( approximately 10 ps) and slow ( approximately 100 ps and approximately 500 ps) pathways were found in rods consisting of PE and PC. Energy transfer time from PE to PC was two times slower in G. violaceus than in F. diplosiphon grown under green light. 相似文献
84.
The evolutionary route from anoxygenic photosynthetic bacteria to oxygenic cyanobacteria is discontinuous in terms of photochemical/photophysical reaction systems. It is difficult to describe this transition process simply because there are no recognized intermediary organisms between the two bacterial groups. Gloeobacter violaceus PCC 7421 might be a model organism that is suitable for analysis because it still possesses primordial characteristics such as the absence of thylakoid membranes. Whole genome analysis and biochemical and biophysical surveys of G. violaceus have favored the hypothesis that it is an intermediary organism. On the other hand, species differentiation is an evolutionary process that could be driven by changes in a small number of genes, and this process might give fair information more in details by monitoring of those genes. Comparative studies of genes, including those in Acaryochloris marina MBIC 11017, have provided information relevant to species differentiation; in particular, the acquisition of a new pigment, chlorophyll d, and changes in amino acid sequences have been informative. Here, based on experimental evidence from these two species, we discuss some of the evolutionary pathways for the appearance and differentiation of cyanobacteria. 相似文献
85.
Reaction center (RC) complexes isolated from a Zn-bacteriochlorophyll (BChl) a-containing purple bacterium, Acidiphilium rubrum, were characterized by absorption, circular dichroism, and magnetic circular dichroism (MCD) spectroscopy. The oxidized-minus-reduced difference spectra indicated that, in this RC, the Zn-BChl a is the primary electron donor. The molecular structure of the donor was examined by measuring the ratio of the MCD intensity of the Faraday B-term (B) to the dipole strength (D). In the Q(y) region, B/D for the donor was about half those of bacteriopheophytin a and the accessory Zn-BChl a, indicating that the primary electron donor is a dimer. The magnitude of bleach of the Q(x) band was half that observed in Rhodobacter sphaeroides, suggesting the cation is localized on a single Zn-Bchl a. The absorption intensity of the higher-energy Q(y) exciton band was approximately 28% of that of the lower-energy band, and the exciton splitting was approximately 570 cm(-1), smaller than that in Rb. sphaeroides. These results indicate that, in A. rubrum, the primary electron donor is a Zn-BChl a dimer but that the interaction between the two molecules is rather weak. On the basis of these results, an adaptive strategy for changes in BChl a species is discussed from an evolutionary perspective. 相似文献
86.
N-terminus conservation in the terminal pigment of phycobilisomes from a prokaryotic and eukaryotic alga 总被引:7,自引:3,他引:4
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High molecular weight polypeptides from phycobilisomes, believed to be involved in facilitating the energy flow from phycobilisomes to thylakoids, are conserved in the prokaryote Nostoc sp. and the eukaryote Porphyridium cruentum. Partial N-terminal sequence analysis of the phycobilisome-polypeptides of Nostoc (94 kilodalton) and Porphyridium (92 kilodalton) revealed 55% identity in the first 20 residues, but no significant homology with sequences of other phycobiliproteins or phycobilisome-linkers. Polypeptides (94 and 92 kilodalton) from Nostoc thylakoids free of phycobilisomes, previously presumed to be involved in the phycobilisome-thylakoid linkage (M Mimuro, CA Lipschultz, E Gantt 1986 Biochim Biophys Acta 852: 126) exhibit the same immunocrossreactivity but are different from the 94 kilodalton-phycobilisome polypeptide by having blocked N-termini and a different amino acid composition. 相似文献
87.
Type 1 plasminogen activator inhibitor (PAI-1) binds to the extracellular matrix of cultured bovine aortic endothelial cells. Bovine plasma and bovine lung extract contain protein(s) that bind to PAI-1 and prevent this interaction. One of these proteins was purified approximately 425-fold from ammonium sulfate-fractionated plasma using standard chromatographic procedures together with affinity chromatography on PAI-1-Sepharose. The final product consisted of a major polypeptide of Mr 65,000 and two minor polypeptides of Mr 80,000 and 57,000. NH2-terminal amino acid sequence analysis of the Mr 65,000 polypeptide revealed that it was homologous with vitronectin, and antiserum against this purified binding protein recognized vitronectin and vice versa. Immunological analysis using these antisera demonstrated that the three peptides were immunologically related, and that vitronectin was present in the extracellular matrix of bovine endothelial cells and also in bovine lung. 相似文献
88.
Fibrinolytic components in nasal mucosa and nasal secretion 总被引:1,自引:1,他引:0
Toyotoshi Yasuda Y. Sakata Seiji Madoiwa Jun Mimuro Michio Matsuda Ken Kitamura 《Histochemistry and cell biology》1998,110(5):449-455
We evaluated a possible role for fibrinolytic components in nasal secretion by tissue localization with immunohistochemical
techniques and by measuring their antigen concentrations in nasal discharge by means of ELISA and fibrin autography. Nasal
mucosa was obtained surgically from the inferior turbinate. Urokinase-type plasminogen activator (u-PA) specific staining
was observed in pseudostratified ciliated epithelium and was predominant in mucous cells of the seromucinous gland, while
serous cells were almost devoid of stain. The pattern of staining of plasminogen activator inhibitor-2 was similar to that
of u-PA. In contrast, plasminogen activator inhibitor-1(PAI-1) immunoreactive material was localized exclusively in serous
cells of seromucinous glands. Positive staining for tissue-type plasminogen activator (t-PA) was observed in endothelial cells
and basal cells, which differentiate into either ciliated or goblet cells. Nasal secretions were partially fractionated by
immunospecific antibody-immobilized Sepharose. Subsequent fibrin autography patterns indicated the presence of u-PA, PAI-1,
and t-PA. After methacholine provocation, the level of t-PA increased transiently but decreased rapidly with subsequent challenges.
These differential stainings of fibrinolytic components and the existence of PAs and PAI-1 in the nasal discharge suggest
that the fibrinolytic system may play a role in the movement and fluidity of nasal secretion.
Accepted: 25 May 1998 相似文献
89.
K Miki T Ezoe A Masui T Yoshisaka M Mimuro T Fujiwara-Arasaki N Kasai 《Journal of biochemistry》1990,108(4):646-649
C-Phycocyanin from a red alga, Porphyra tenera, has been crystallized by the vapor-diffusion procedure. Both orthorhombic and hexagonal forms were obtained from ammonium sulfate solutions, whereas only the orthohombic form was selectively grown from sodium citrate solutions. The orthorhombic crystals are more suitable for further crystallographic work; their space group is P2(1)2(1)2(1), with unit-cell dimensions of a = 105, b = 121, and c = 184 A. The asymmetric unit comprises two (alpha beta)3 trimer molecules of C-phycocyanin. These crystals diffract X-rays up to about 3 A resolution. 相似文献
90.
The majority of type 1 plasminogen activator inhibitor associated with cultured human endothelial cells is located under the cells and is accessible to solution-phase tissue-type plasminogen activator 总被引:9,自引:4,他引:5
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R R Schleef T J Podor E Dunne J Mimuro D J Loskutoff 《The Journal of cell biology》1990,110(1):155-163
The interactions between exogenously added tissue-type plasminogen activator (t-PA) and the active form of type 1 plasminogen activator inhibitor (PAI-1) produced by and present in cultured human umbilical vein endothelial cells (HUVECs) were investigated. Immunoblotting analysis of the conditioned media obtained from monolayers of HUVECs treated with increasing concentrations of t-PA (less than or equal to 10 micrograms/ml) revealed a dose-dependent formation of both t-PA/PAI-1 complexes, and of a 42,000-Mr cleaved or modified form of the inhibitor. Immunoradiometric assays indicated that t-PA treatment resulted in a fourfold increase in PAI-1 antigen present in the conditioned media. This increase did not result from the release of PAI-1 from intracellular stores, but rather reflected a t-PA-dependent decrease in the PAI-1 content of the Triton X-100 insoluble extracellular matrix (ECM). Although the rate of t-PA-mediated release of PAI-1 was increased by the removal of the monolayer, similar quantities of PAI-1 were removed in the presence or absence of the cells. These results suggest that the cells only represent a semipermeable barrier between ECM-associated PAI-1 and exogenous t-PA. Treatment of HUVECs with t-PA (1 microgram/ml, 2 h) to deplete the ECM of PAI-1 did not affect the subsequent rate of PAI-1 production and deposition into the ECM. Immunogold electron microscopy of HUVECs not only confirmed the location of PAI-1 primarily in the region between the culture substratum and ventral cell surface but failed to demonstrate significant (less than 1%) PAI-1 on the cell surface. Thus, the majority of PAI-1 associated with cultured HUVEC monolayers is present under the cells in the ECM and is accessible to solution-phase t-PA. 相似文献