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  • 1
    ISSN: 1432-1254
    Keywords: Key words Skin tissue oxygen saturation ; Total hemoglobin ; Near-infrared spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  The oxygen saturation (StO2) and total hemoglobin volume in cutaneous blood are closely related to cutaneous metabolism and are important factors in determining the skin color. Most conventional apparatuses for the measurement of cutaneous metabolism have been designed to evaluate qualitative changes in the oxyhemoglobin volume, deoxyhemoglobin volume, and their sum (total Hb volume) relative to their baseline values. In this study, we developed an instrument for non-invasive evaluation of individual and regional differences in StO2 and Hb volume, a system unaffected by melanin (Kao PSA system model III), and examined the validity of its application. First, changes in StO2 and total Hb volume in the antebrachial region during venous occlusion and devascularization by compression of the brachial region were evaluated. Changes in total Hb volume following venous occlusion were found to reflect the cutaneous blood flow. Also, StO2 was considered to reflect the state of oxygen consumption by the skin, because it was markedly reduced during devascularization. Next, the subjects were exposed to graded hypobaric conditions, and the relationships among StO2, arterial blood oxygen saturation (SaO2), and venous blood oxygen saturation (SvO2) were studied. StO2 showed significant positive correlations with SaO2 (r=0.811, P〈0.001) and SvO2 (r=0.966, P〈0.001), and its correlation with SvO2 was particularly strong. Therefore, StO2 was found to be closely dependent on SvO2. Lastly, StO2, total Hb volume, and other parameters were measured in healthy women (aged 20–69 years), and their regional differences and age- associated changes were evaluated. These regional differences (angle of mouth 〉 cheek 〉 forehead) and age-associated decreases in StO2 are considered to be caused by the age-associated decreases in the cutaneous blood flow.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 44 (2000), S. 24-30 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  In this research, we hypothesized that, in rats, adaptation to high altitude (2500 m) plus training at low altitude (610 m), ”living high–training low”, improves physical performance at low altitude more than living and training at low altitude (610 m). Rats were divided into four groups: (1) living at low altitude (LL, n=12), (2) living and training at low altitude (LLTL, n=13), (3) living at high altitude (LH, n=12), (4) living at high altitude and training at low altitude (LHTL, n=13). The program for living at high altitude involved raising rats under hypobaric hypoxia (equivalent to 2500 m), and the training program consisted of running on a tread-mill at low altitude. All groups were raised at each altitude and trained to run at 35 m/min for 40 min/day, 6 days/week for 6 weeks. During this program, we measured heart rates both at rest and during exercise, and performed running-time trials. The mean heart rate during exercise was lower in groups with training than in groups without training, and the groups receiving training could run longer than the untrained groups. The LHTL group especially showed the lowest mean heart rate during exercise and the longest running time among all groups. After 6 weeks of the training program, all rats had a catheter implanted into the carotid artery, and the mean systemic arterial pressure was continuously measured during treadmill running. The rate of increase of this pressure as the running intensity increased was lower in groups with training than in groups without training, especially in the LHTL group. Finally, we anesthetized all the rats and extracted both the right and left ventricles, and the triceps surae and liver. Training increased the weight of the left ventricle, triceps surae, and liver. The increase in weight of the left ventricle and triceps surae was higher in the LHTL group than in the LLTL group in particular. It appeared that living high– training low may be an effective strategy to improve performance ability at low altitude.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1617-4623
    Keywords: Cyanidioschyzon merolae ftsZ Mitochondrial division Plastid division Primitive red alga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Two ftsZ homologues were isolated from the unicellular primitive red alga Cyanidioschyzon merolae (CmftsZ1 and CmftsZ2). Phylogenetic analysis revealed that CmftsZ1 is most closely related to the ftsZ genes of α-Proteobacteria, suggesting that it is a mitochondrial-type ftsZ gene, whereas CmftsZ2 is most closely related to the ftsZ genes of cyanobacteria, suggesting that it is a plastid-type ftsZ gene. Southern analysis indicates that CmftsZ1 and CmftsZ2 are both single-copy genes located on chromosome XIV in the C. merolae genome. Northern analysis revealed that both CmftsZ1 and CmftsZ2 are transcribed, and accumulate specifically before cell and organelle division. The results of Western analysis suggest that CmFtsZ1 is localized in mitochondria.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2145
    Keywords: Key words Erythrina ; Generative cell ; DNA-containing organelle ; Plumbago ; Preferential double fertilization ; Sperm cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The generative cell at anthesis in the mature pollen grain of Erythrina crista-galli (Fabaceae) was examined by 4,6-diamidino-2-phenylindole(DAPI)-fluorescence microscopy using the squash method. An unequal, polarized distribution of DNA-containing organelles (plastids and/or mitochondria) within the generative cell was observed in every mature pollen grain examined. Polarization of DNA-containing organelles is obvious when generative cells are freed and assume a spherical shape soon after microspore mitosis, as revealed by fluorescence-microscopic observations of specimens embedded in Technovit 7100 resin and thin-sectioned at different developmental stages. Early establishment of polarized localization of organelles in young generative cells of E. crista-galli and maintenance of this unequal distribution until pollen maturation strongly suggests that the organelles may still be clustered at pollen mitosis. Production of a dimorphic pair of sperm cells, as has been reported in Plumbago zeylanica, was observed in some pollen tubes germinated in vitro. The differentiation of the two sperm cells is discussed in relation to possible preferential double fertilization in angiosperms.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1615-6102
    Keywords: 3,3′-dihexyloxacarbocyanine iodide ; Male gametogenesis ; Mitochondria ; Nuclear envelope ; Pollen ; Pharbitis nil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in the number and distribution of mitochondria in microspores and pollen grains during male gametogenesis inPharbitis nil were examined with Technovit sections stained with 3,3′-dihexyloxacarbocyanine iodide. The number of mitochondria per microspore or pollen grain ofP. nil increased constantly and dramatically during male gametogenesis. During this process, mitochondria exhibited characteristic localizations: subpopulations of mitochondria covered the surface of the microspore and vegetative nuclei before and again just after postmeiotic mitosis I (9 and 5 days before flowering, respectively). The mitochondria also surrounded the generative nucleus 2 days after postmeiotic mitosis I (5 days before flowering), although the density of mitochondria on the nuclear surface was lower. Electron microscopy showed that the mitochondria were about 30 nm from the nuclear envelope and that each mitochondrion was located near a nuclear pore. The characteristic localization of mitochondria inP. nil pollen may serve as a model to analyze the mechanisms that control mitochondrial positioning within a cell and interactions between mitochondria and nuclei.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 214 (2000), S. 180-193 
    ISSN: 1615-6102
    Keywords: Amyloplast ; Coleoptile ; Development ; Mitochondrion ; Oryza sativa ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The coleoptile of rice (Oryza sativa L. cv. Nippon-bare) emerges from the imbibed seed on day 2 after sowing and ceases its growth on day 3. In cross section, the cells near the outer epidermis turn into green between days 2 and 3, while those near the inner epidermis remain colorless. In this study, the complete process of the development in the nongreening cells in the coleoptile was examined by fluorescence and electron microscopy. Embryonic morphology on day 0 was rapidly converted into the differentiated greening or nongreening cells between days 1 and 2. Senescence in the inner, nongreening region first appeared on day 4 in the third or fourth cell layer from the inner epidermis and then spread towards both the inner and the outer epidermis, and the inner cells collapsed completely before the outer cells senesced. Cells adjacent to the inner epidermis, which senesced slowly, followed a sequence of events during development: (1) degradation of plastid DNA; (2) dispersal of nuclear chromatin, differentiation of plastids into amyloplasts, degradation of mitochondrial DNA; (3) degradation of the starch in amyloplasts; (4) disorganization of plastids; (5) condensation of the nucleus, shrinkage of mitochondria; (6) complete loss of cellular components, distortion of cell walls. In the interior cells, the early events including degeneration of plastid DNA and mitochondrial DNA occurred in parallel with those in the cells adjacent to the inner epidermis, yet rapid collapse of all the cellular components proceeded between days 3 and 5, and nuclear condensation could not be detected.
    Type of Medium: Electronic Resource
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