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101.
The dielectric dispersion of isolated intact mitochondria in suspension has been measured between 10 kHz and 500 MHz. In isotonic KCI media at 4°C, the mitochondria maintained their characteristic ‘double membrane’ structure as examined by electron microscopy, and the observed dispersion curves were successfully simulated in terms of a superposition of two sub-dispersions having different characteristic frequencies and different permittivity magnitudes. Taking these observations into account we analyzed the dispersion data on the basis of a ‘double-shell’ model in which two concentric shells are meant to represent the mitochondrial outer and inner membranes. The analyses by a computerized curve-fitting method revealed that: (i) electric capacities for the outer and the inner membrane are 1.7 and 0.5 μF/cm2, respectively, (ii) relative permittivity for the inner compartment (or the equivalent homogeneous matrical space) = 50–60, (iii) outer compartment-to-external conductivity ratio = 0.4–0.6, and (iv) inner compartment-to-external conductivity ratio = 0.14. The implications of these parameter values are discussed with due attention paid to the limitations inherent in our ‘double-shell’ model approach. 相似文献
102.
Relation between Nitrogen and Ribulose-1,5-bisphosphate Carboxylase in Rice Leaves from Emergence through Senescence 总被引:24,自引:0,他引:24
The relation between N content and ribulose-l,5-bisphosphate(RuBP) carboxylase protein was examined in the 12th leaf bladeof rice. Plants were grown under different amounts of N afterthe emergence of the 12th leaf blade. RuBP carboxylase proteinincreased with leaf N during leaf expansion. The synthesis ofRuBP carboxylase predominated during this period, and changesin the amounts of carboxylase synthesized until leaf death paralleledchanges in the N influx to the leaves. When the carboxylasereached its maximum content, the proportion of RuBP carboxylaseto leaf N was 27 to 28% irrespective of N treatment. As theleaf senesced, however, this proportion differed significantlywith the treatment. It was higher in the N-deficient leaf thanin the N-sufficient leaf. This was due to different patternsof RuBP carboxylase degradation for the treatments during senescence.RuBP carboxylase was degraded actively during the early stageof senescence in the N-sufficient leaf, whereas its degradationproceeded almost constantly in the N-deficient leaf during senescence. (Received October 17, 1983; Accepted January 27, 1984) 相似文献
103.
T. Takizawa H. Fujii S. Takegawa K. Takahashi A. Hirono T. Morisaki H. Kanno R. Oka H. Yoshioka S. Miwa 《Human genetics》1984,68(1):70-72
Summary A new glucose 6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was discovered in Japan. The patient showed hemolytic crises after upper respiratory infections. The enzyme activity was about 3.8% of the normal. The partially purified enzyme revealed slow anodal electrophoretic mobility, high Km NADP, marked thermal-instability, and increased affinity for a substrate analogue (deamino-NADP). A particular characteristic of this enzyme was a biphasic pH curve with a greatly increased activity at low pH values. From these results, this variant was clearly different from hitherto observed G6PD variants, and was designated G6PD Asahikawa. 相似文献
104.
M. Tachibana H. Morioka M. Machino W. Oshima F. Mizukoshi O. Mizukoshi T. Yoshioka 《Histochemistry and cell biology》1984,81(2):157-160
Summary Triphosphoinositide (TPI) has been demonstrated to be a receptor for aminoglycosides in the cochlea and may regulate ionic permeability by its binding with Ca++. This phospholipid was localized by a protein A-gold technique in the cochlea at the electronmicroscopic level. TPI was prepared by a neomycin column and antibodies to it were raised in rabbits. The antibody used in this study reacted virtually only to TPI among the tested lipids. TPI was localized mainly at stereocilia, cuticular plates, head plates of Deiter's cells, plasma membrane, and mitochondria of various cells in the organ of Corti. In the vascular stria, TPI was found mainly at the plasma membrane of basal infoldings of the marginal cells. Possible physiological and pathophysiological roles of TPI in the cochlea are briefly discussed. 相似文献
105.
Phototransformation of the far-red light absorbing form (PFR)of large pea phytochrome to the red-light absorbing form (PR)was examined at 2?C after a 715 nm laser flash excitation usinga custom-built multichannel transient spectra analyzer. Themaximum amount of phototransformation intermediates was producedby a pulse of about 50 mJ, which resulted in ca. 65% of PR obtainedat the photostationary equilibrium. Some flash-induced intermediateswere assumed to return to PFR in the dark. A difference spectrummeasured at 10 µsec after the flash showed an absorbanceincrease at 651 nm and a decrease at 724 nm. When the samplewas left in darkness after the flash light irradiation, absorbancein the red and far-red region gradually increased, but thatin the green region rapidly decreased. The decay curve of intermediatesmeasured at 554 nm could be resolved into three reaction componentshaving rate constants of 2,500, 590 and 48 sec1, respectively.Difference spectra also indicated that a small but significantincrease in absorbance between 370 and 380 nm and a decreasearound 415 nm took place 10310 µsec after a flash. (Received February 13, 1982; Accepted April 21, 1982) 相似文献
106.
The position of the gametophytic bud was examined in relationto the development of protonema in the moss, Physcomitrium sphaericum. Positions of protrusion formation, of the development of protrusionsinto lateral filaments, and of the differentiation of protrusionsinto buds are restricted within the narrow regions of the filaments.The number of cells from the apical cell of the filament tothese positions are constant in any size filament. The growth pattern of the protonema is shown as follow. As afilament grows one-dimensionally through divisions of the apicalcell, new protrusions are produced successively on the 5th cellfrom the apical cell or on its vicinity. The cells which intervenebetween the apical cell and this protrusion increase in numberas the apical cell divides. When this protrusion is positionedat the 8th or 9th cell from the apex, it differentiates intoa bud or a lateral filament. This growth pattern is common toboth the main and lateral filaments. Buds are differentiated not only on caulonema cells in the mainand lateral filament, but also on chloronema cells at the baseof the lateral filaments. (Received December 14, 1981; Accepted April 24, 1982) 相似文献
107.
When thiamine concentration in subculture medium was rapidlylowered to nil, soybean cells in suspension became necroticand stopped growing entirely. When it was gradually lowered,cell growth was vigorous until the concentration was reducedto 7.8?103 mg/liter. The cells at this level of thiamineceased growing for a time, but prolonged culture in the samemedium resulted in the appearance of fresh white cells whichcould be easily distinguished from the old brown, necrotic cellsin the aggregates. These new cell lines could be subculturedwith further reduction in the thiamine supply, growing as largeraggregates of about 4 mm in diameter. New cell lines were similarly obtained by prolonged culturesin media containing a thiamine precursor; three lines appearedto be habituated to the pyrimidine moiety and one to the thiazolemoiety. The latter cell line could be subcultured without thiamineand its precursors for at least eight passages. These habituatedcells were characterized by the increase of the dry to freshweight ratio and by their growth in large aggregates.
1Present address: Section of Phytochemical Research, Eisai Co.,Ltd., Kawashima, Gifu 483, Japan. (Received December 15, 1978; ) 相似文献
108.
On the basis of recent neurophysiological findings on the mammalian visual cortex, a selforganizing neural network model is proposed for the understanding of the development of complex cells. The model is composed of two kinds of connections from LGN cells to a complex cell. One is direct excitatory connections and the other is indirect inhibitory connections via simple cells. Inhibitory synapses between simple cells and complex cells are assumed to be modifiable. The model was simulated on a computer to confirm its behavior. 相似文献
109.
Immunological responses of hamsters in the acquired immune state to Mycoplasma pneumoniae infection 总被引:1,自引:0,他引:1
E Hayatsu Y Kawakubo M Yayoshi M Araake M Wakai A Yoshida M Yoshioka Y Nishiyama 《Microbiology and immunology》1981,25(12):1255-1263
Protective effects of vaccination of hamsters against Mycoplasma pneumoniae infection, evaluated according to the recovery of mycoplasmas and histopathological changes in the respiratory tract after challenge infection, persisted for at least 6 months after the final vaccination. Serum antibody levels reached a maximum in the second week after the last vaccination and decreased markedly between the first and the third months, but increased again in sera obtained from animals given booster injections. Metabolism-inhibiting antibodies were detected in bronchial washings of animals showing high resistance obtained by vaccinal or passive immunization. Antiserum transfer was also effective for protection but cell-mediated immune responses were not demonstrated in any animals up to 6 months after the vaccination. Even after 10 months, suppression of both mycoplasmal proliferation and lung lesions was apparent, and a single dose of the vaccine induced a significant booster effect. These findings suggest that (1) humoral immunity is more important than cell-mediated immunity in resistance of hamsters to M. pneumoniae pneumonia, and (2) the antibody secreted in the respiratory tract may be involved in the local defense mechanisms. 相似文献
110.
The structure for trichoclin, (E)-8-(3-methyl-4-hydroxy-2-butenyloxy)-psoralen, a new furocoumarin isolated from Trichocline incana, has been established. Phellopterin and isopimpinellin were also obtained. The new side chain of trichoclin was confirmed by synthesis. 相似文献