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  • 1
    ISSN: 0741-0581
    Keywords: 3-D reconstruction ; Computer graphics ; Serial sections ; Yeast target cell ; Tooth movement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A computer graphics system for reconstruction from serial section micrographs was applied to intracellular details of a yeast target cell (Saccharomyces cerevisiae cell) induced by the α factor mating pheromone and was also applied to a periodontal structure of a dog tooth moved orthodontically. In the former, intracellular organelles and a distribution of vesicles could be clearly observed through the cell membrane using the transparent display method in which the smoothing of the reconstructed outer cell membrane surface by computer processing was applied to the transparent display. In the latter case, by cutting through a reconstructed dog tooth and its periodontal tissues, labiolingual and mesiodistal cut surfaces of the tooth and of adjacent alveolar bone could be observed with fine details (232 sections were used).
    Additional Material: 6 Ill.
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  • 2
    ISSN: 0741-0581
    Keywords: STEM ; On-line computer system ; Digital image processing ; Unstained biological specimen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Recently, the reliability of field-emission electron guns has increased. In addition, the cost of computer systems for on-line processing has dropped. Hence, we should now consider the use of scanning transmission electron microscopy (STEM) for routine work, especially, in the field of biology where one may expect to utilize digital image processing techniques.An STEM has been constructed, without disturbing the original functions, by converting a commercial scanning electron microscope equipped with a fieldemission gun. The STEM is generally operated at accelerating voltage 30 kV, focal length 7.5 mm, and beam current 1-2 × 10-10 A. Several improvements have been incorporated for removing the effects of vibration, contamination, and stray magnetic fields. Also, an adjustable detector aperture was utilized. The modified instrument was connected to an on-line digital image processing system for utilizing the information obtained from STEM images. The advantages of the modified system were studied from various viewpoints.
    Additional Material: 14 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 475-489 
    ISSN: 0886-1544
    Keywords: digital image processing ; flagella ; cilia ; bends ; Hemicentrotus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A novel method of digital image analysis of the bends of eukaryotic flagella and cilia was devised. In the analysis system, all image pixels were systematically extracted and processed to measure angular direction and curvature. Simulation experiments on theoretical model pictures of flagella with sine-generated or arcstraight line bending waves demonstrated that the method can be used with considerable high accuracy. This method then revealed abrupt changes in slope of the curvature in sperm flagella and embryo cilia of the sea urchin, Hemicentrotus pulcherrimus. This indicates that the digital image processing used may be helpful in the study of flagellar and ciliary movements.
    Additional Material: 7 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 374-379 
    ISSN: 0886-1544
    Keywords: flagellar movement ; reactivation ; sea urchin sperm ; pH jump ; sliding-bending conversion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of rapid pH drop on the flagellar movement of reactivated sea urchin sperm were studied by video microscopy and by a newly developed pH jump method. Triton-demembranated sperm were reactivated in a thin layer of the reactivation medium containing ATP and potassium acetate and supported by a ring-shaped Millipore filter stuck to the lower surface of a supported coverslip. The pH of the medium was lowered rapidly by dissolving acetic acid vapor abruptly introduced into a gap between the cover and slide. Flagellar beating ceased immediately when the pH of the reactivation medium was lowered. At least two types of cessation were distinguished: (1) “instantaneous” cessation in a bent form closely resembling those characteristic of steady-state beating before pH drop (waveform freeze), and (2) flagellar quiescence in a cane-shaped form resembling those characteristic of Ca-induced quiescence (cane-shaped quiescence). The flagellum again began beating if the pH was raised to normal but eventually was disintegrated by tubule sliding if the pH was left lowered. Field-by-field analysis of the transient movement of flagella becoming quiescent upon pH drop demonstrated that the proximal bend of the cane-shaped form corresponded to the principal bend of the steady-state beating in some flagella, but in others, to the reverse bend. These observations indicate that low pHs affect flagellar beating by interfering with sliding-bending conversion by a mechanism different from that previously reported.
    Additional Material: 3 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 198-208 
    ISSN: 0886-1544
    Keywords: high-speed microcinematography ; Hemicentrotus ; primitive response ; ciliary reversal ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Transient ciliary movement during responses to electric stimulation of embryos of the sea urchin, Hemicentrotus pulcherrimus, was analyzed in terms of angular direction with a time resolution of approximately 2 ms with high-speed microcinematography. In the primitive response, which can be induced only in the early stages of development of the embryo, bending transients always started with a short pause in the middle of the effective stroke, irrespective of beat position on stimulation. In the reversal response, induced only in the late stages of development, bending transients occurred with a delay as short as some 10 ms from stimulation, and with a transient sharp deviation from the normal beat before the cilium took the position of the beginning of the recovery stroke of the reversed beat. The delay was significantly shorter at the base than at the tip, suggesting that some form of signal travels along the cilium; the speed was ten times higher than that of propagating bends in the normal beat. These facts indicate that the sensitivity to internal changes resulting from stimulation of the axoneme may vary with development, ciliary beat positions, and regions along the cilium.
    Additional Material: 7 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 351-352 
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 1 Ill.
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  • 7
    ISSN: 1040-452X
    Keywords: Acrogranin ; Spermatogenesis ; Acrosomal marker ; Sperm ; Testis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Spermatogenesis is a unique system of differentiation involving cellular remodeling and the biogenesis of sperm-specific organelles. To study the biogenesis of one such organelle, the acrosome, we have been examining the gene expression, biosynthesis, and targeting of specific acrosomal proteins during mammalian spermatogenesis. An acrosomal marker that we recently purified and began characterizing is acrogranin, a 67,000-molecular-weight glycoprotein originally isolated from guinea pig testes. This glycoprotein is detected in pachytene spermatocytes and is found later in the acrosomes of developing spermatids and sperm. Immunoblotting of several tissues and immunofluorescent localization in frozen sections of guinea pig testes suggested that acrogranin was a germ cell-specific glycoprotein that was expressed meiotically and post-meiotically. However, Northern blot analysis demonstrated that the mRNA for acrogranin was ubiquitously expressed in all guinea pig and mouse tissues examined. Furthermore, the primary structures of guinea pig and mouse acrogranins, deduced from the cDNA sequences, reveal that this glycoprotein is a cysteine-rich molecule with a motif that is tandemly repeated seven times, very similar to that of the human epithelin/granulin precursor. We conclude that guinea pig and mouse acrogranins are homologues of the precursor of the human and rat epithelin/granulin peptides previously demonstrated to have growth-modulating properties. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 437-457 
    ISSN: 1059-910X
    Keywords: Dystrophin ; Actin ; Spectrin ; Dystrophin related protein ; Quick-freezing ; deep-etching method ; Muscle culture ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We studied the developmental changes of localization of dystrophin and other cytoskeletal proteins, especially actin, spectrin and dystrophin related protein (DRP) using immunocytochemistry and quick-freezing and deep-etching (QF-DE) method.In development studies of mouse and human muscle cultures, some myoblasts had positive reactions to spectrin, DRP, and F-actin, but not dystrophin. In aneurally cultured myotubes, dystrophin, DRP, and spectrin were localized diffusely in the cytoplasm and later in discontinous patterns on the plasma membrane, when myotubes became mature. Spectrin and DRP had more positive reactions in immature myotubes, compared with those of dystrophin.In some areas of myotubes, dystrophin/spectrin and spectrin/actin were localized reciprocally. In innervated cultured human muscle cells, dystrophin and DRP were localized in neuro-muscular junctions, which were co-localized with clusters of acetylcholine receptors.By using the QF-DE method, dystrophin was localized just underneath the plasma membrane, and closely linked to actin-like filaments (8-10 nm in diameter), most of which were decorated with myosin subfragment 1. In actin-poor regions, spectrin was detected as well-organized filamentous structures in highly interconnected networks with various diameters. DRP was distributed irregularly with granular appearance inside the cytoplasm and also under the plasma membrane in immature mouse myotubes.Our present studies show that dystrophin, spectrin, and DRP are localized differently at the developmental stages of myotubes. These results suggest that dystrophin, spectrin, and DRP are organized independently in developing myotubes and these cytoskeletal proteins might play different functions in the preservation of plasma membrane stability in developing myotubes. © 1995 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 331-340 
    ISSN: 0741-0581
    Keywords: Digital image processing ; Laplacin filter ; Scanning electron microscopy ; High-resolution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Certain digital image-processing methods, which are useful for nonperiodic structural images, have been applied to high-resolution SEM images for the improvement of resolution. Samples utilized in the present study consisted of magnetic tape coated with gold, T4 phage coated with gold-palladium, and uncoated specimens of Prolamellar body (PLB) in Cucurbita moschata. These images were blurred and otherwise disturbed by electronic noise, though the images were taken at the limit of efficiency of intrinsic instrument. The major image-processing tool was the Laplacian filter, which subtracts the Laplacian from the original image. Noise, which is a serious problem in digital processing of high-resolution SEM images, was suppressed by the nonlinear type smoothing method. Also, the noise was evaluated by an autocorrelation function and a power spectrum of the image. By using these methods of “deblurring” and noise removal, we achieved better resolution, and structural details of our biological specimens were revealed.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986), S. 113-125 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 9 Ill.
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