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  • 1
    Electronic Resource
    Electronic Resource
    Substructure of paramyosin filaments prepared by freeze-substitution technique (1973)
    Springer
    Cellular and molecular life sciences 29 (1973), S. 469-471 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung In den Paramyosinfilamenten des Byssusretraktors vonMytilus edulis wurde eine komplizierte Substruktur beobachtet, wenn das Gewebe nicht fixiert, sondern gefriersubstituiert wurde. Längsgetroffene Filamente zeigen ein netzartiges oder quergebändertes Aussehen, quergeschnittene Filamente weisen häufig eine scheibenartige Struktur auf.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01926788
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  • 2
    Electronic Resource
    Electronic Resource
    Ca2+-Dependent deposits at the plasmalemma of Chara internodal cells (1983)
    Springer
    Histochemistry and cell biology 79 (1983), S. 69-75 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron dense deposits (EDD) were observed on the extracellular side of the plasmalemma of Chara internodal cells by a calcium-glutaraldehyde fixation technique. The number and size of EDD were greatly increased when cells had been preincubated in Ca2+-enriched medium before fixation. The addition of Na+, Mg2+, or La3+ instead of Ca2+ in incubation and fixation media produced no deposits at all, Sr2+ caused deposits with similar distribution to those formed by Ca2+, and Ba2+ addition resulted in deposits localized at different sites within the cell. Microprobe analysis of single EDD from Ca2+ incubated cells ascertained the presence of calcium in these deposits. Possible functions of the Ca2+-binding sites at the plasma membrane of Chara cells are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00494343
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  • 3
    Electronic Resource
    Electronic Resource
    Microwave-stimulated glutaraldehyde and osmium tetroxide fixation of plant tissue: ultrastructural preservation in seconds (1992)
    Springer
    Histochemistry and cell biology 97 (1992), S. 341-347 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microwave-enhanced fixation of animal tissues for electron microscopy has gained in interest in recent years. Attempts to use microwave irradiation for the preparation of plant tissues are rare. In this study, I report on microwave conditions which allow a high quality preservation of plant cell structure. Tissues used were: internodes of Chara vulgaris, leaves of Hordeum vulgare, root tips of Lepidium sativum. Microwave irradiation was done with a commercial microwave oven (Sharp R-5975). Fixatives used were: 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and 1% osmium tetroxide in veronal/acetate buffer, pH 7.2. Conventional fixations with glutaraldehyde/osmium were compared with microwave fixations. Examinations of thin sections showed that microwave fixation (glutaraldehyde or sequential aldehyde/osmium) is an attractive and rapid alternative method for processing plant tissues for electron microscopy. The optimal conditions found were: microwave oven at power level 50 W, 6.5 ml of fixative solution, irradiation times between 32–34 s, final temperature between 40° C and 47° C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270036
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  • 4
    Electronic Resource
    Electronic Resource
    A regular actin filament lattice in a vertebrate smooth muscle (1970)
    Springer
    Cellular and molecular life sciences 26 (1970), S. 1131-1132 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung In den glatten Muskelfasern aus dem Dickdarm der Maus wurde eine charakteristische Verteilung der Aktinfilamente gefunden. Die Filamente sind zu BÜndeln zusammengelagert, die parallel zur Faserlängsachse ausgerichtet sind. Innerhalb der BÜndel liegen die Filamente in dichter hexagonaler Packung. Die Dimensionen des gefundenen Filamentmusters stimmen sehr gut mit den durch Röntgenbeugungsanalysen ermittelten Überein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112718
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  • 5
    Electronic Resource
    Electronic Resource
    Are intermediate filaments of vertebrate smooth muscle cells and tonofilaments of epithelial cells identical cell structures? (1978)
    Springer
    Cellular and molecular life sciences 34 (1978), S. 649-650 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In epithelial and smooth muscle cells of the urinary bladder of the frog, a class of filaments exists which is partly disintegrated by glycerol treatment and very resistant to potassium solutions of high ionic strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01937013
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  • 6
    Electronic Resource
    Electronic Resource
    High concentration of plasma membrane H+-ATPase in root caps ofLepidium sativum L. (1993)
    Springer
    Naturwissenschaften 80 (1993), S. 317-319 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01141903
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of heavy metals on growth and ultrastructure ofChara vulgaris (1987)
    Springer
    Protoplasma 136 (1987), S. 37-48 
    Details
    ISSN: 1615-6102
    Keywords: Chara ; Fine structure ; Growth ; Heavy metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The toxicity of some heavy metals to the common macrophytic freshwater algaChara vulgaris was studied under laboratory conditions. For experiments, apical tips of algae containing two internodes were cultivated for fourteen days in the presence of various concentrations of cadmium, mercury or lead (as triethyl lead or lead nitrate). Fifty percent growth inhibition occurred with concentrations of 8.5×10−8 M (9.5 ppb) cadmium, 7.5×10−7M (150ppb) mercury, 1.6×10−6 M (330ppb) organic lead or 4× 10−5 M (8000 ppb) inorganic lead. Sublethal concentrations of these metals caused alterations in the fine structure of internodal cells which turned out to be at least partly metal-specific or in the case of lead, the effects depended on whether the lead was ionic or organically bound. Cadmium and inorganic lead induced disorders of cell wall microfibrils which resulted in local wall protuberances. Mercury affected the chloroplasts which mostly showed considerably increased grana stacks. In addition, mercury caused a dilation of the endoplasmic reticulum and of the mitochondrial tubuli. Organic lead damaged the membrane system of chloroplasts; sheet- or tubule-like thylakoids were disarranged and showed whorl-like structures. At higher concentrations of organic lead, tubular invaginations of the plasmalemma (“charasomes”) disappeared. The fine structure of nuclei was not altered by any of the metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276316
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  • 8
    Electronic Resource
    Electronic Resource
    Über die Funktionsweise glatter Muskelfasern Elektronenmikroskopische Untersuchungen am Byssusretraktor (ABRM) von Mytilus edulis (1968)
    Springer
    Cell & tissue research 85 (1968), S. 534-551 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die glatten Fasern aus dem vorderen Byssusretraktor (ABRM) der Miesmuschel Mytilus edulis wurden elektronenmikroskopisch untersucht. Unsere besondere Aufmerksamkeit richtete sich dabei auf die Veränderungen, die beim Übergang des erschlafften Zustands in den kontrahierten eintreten. Der kontraktile Apparat, der fast das gesamte Faservolumen einnimmt, besteht aus dicken (170–800 Å) und dünnen (etwa 60 Å) Myofilamenten sowie aus länglichen Z-Elementen, an deren Schmalseiten die dünnen Myofilamente ansetzen. Auf Längsschnitten ist außer einer Parallelorientierung der Myofilamente keinerlei Regelmäßigkeit zu erkennen. Querschnitte zeigen das Vorhandensein von undeutlich umrissenen „A-Zonen“ und „I-Zonen“. Die Kontraktion ist mit einer erheblichen Vermehrung der Myofilamente im Faserquerschnitt und der Dichte ihrer Packung verbunden. Dies kann als ein Anzeichen für eine Verkürzung durch einen Gleitmechanismus angesehen werden. Im Gegensatz zu den erschlafften Fasern sind die kontrahierten uneinheitlich strukturiert. Im Hinblick auf Anordnung und Verteilung der beiden Myofilamenttypen wurden drei verschiedene Muster beobachtet: 1. Dicke und dünne Myofilamente liegen ziemlich gleichmäßig über den ganzen Querschnitt verteilt. 2. Die dicken Myofilamente bilden unregelmäßige und unvollständig voneinander abgegrenzte Gruppen, innerhalb derer die Einzelfilamente vor allem mit ihren Mittelteilen so eng aneinandergelagert sind, daß sich ihr Umriß häufig nur schwierig erkennen läßt. Die Masse der dünnen Filamente liegt in den Zwischenräumen zwischen den Gruppen der dicken. 3. Die dicken Myofilamente finden sich nur in einer zentralen Zone der Faser. Sie liegen hier ebenfalls eng aneinandergepreßt („aggregiert“). Die meisten dünnen Myofilamente sind in eine periphere Zone verlagert. Diese Befunde werden im Hinblick auf mögliche Korrelationen mit den verschiedenen Funktionszuständen des ABRM, also der phasischen Kontraktion und dem Sperrtonus diskutiert.
    Notes: Summary The fine structure of the smooth fibers from the anterior byssus retractor muscle (ABRM) of the mussel Mytilus edulis was investigated in the relaxed and in the contracted state. Most of the fiber volume is occupied by the contractile apparatus. There are thick (between 170 and 800 Å) and thin (about 60 Å diameter) myofilaments. The last ones are attached to spindle shaped Z-elements which lie among the myofilaments at irregular intervals and sometimes appear to be connected with the plasma-membrane. The myofilaments run parallel to each other, but no other regularity is apparent from longitudinal sections. Cross-sections, however, show the presence of irregular “A zones” and “I zones” in these smooth muscle fibers. Contraction leads to a considerable increase in the number of myofilaments per cross-sectional area. This indicates that shortening takes place according to the sliding filament theory. Relaxed fibers seem to be uniform, while contracted ones may differ in their appearence. In those three distinct patterns were observed in the distribution of myofilaments: 1. Thick and thin myofilaments are distributed rather evenly across the whole cross-sectional area. 2. The thick myofilaments are arranged in irregular groups. In each group the filaments touch each other especially in their middle portions. Therefore, it is sometimes difficult to recognize the outline of a particular single filament. Most of the thin filaments occupy the space between the groups of thick filaments. 3. The thick myofilaments are crowded in a central area of the fiber. Here they aggregate, so that little or no interval is left between individual filaments. Most of the thin filaments are found in a peripheral zone of the fiber. These observations are discussed in view of possible correlations to the different functional states of the ABRM: phasic and tonic contraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324747
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  • 9
    Electronic Resource
    Electronic Resource
    Die Feinstruktur der tarsalen Schmeckhaare der Fliege Phormia terraenovae Rob.-Desv. (1971)
    Springer
    Cell & tissue research 117 (1971), S. 419-442 
    Details
    ISSN: 1432-0878
    Keywords: Taste hairs ; Insects ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Schmeckhaare der Fliege Phormia terraenovae enthalten fünf Rezeptorzellen (vier Kontaktchemo- und eine Mechanorezeptorzelle), die von zwei Hüllzellen unter Aussparung von Lymphräumen („Vakuole“) umgeben sind. Die Rezeptorzellen gliedern sich in Axon, Zellkörper und Dendrit, der aus Innenglied, Übergangsabschnitt und Außenglied besteht. Der Übergangsabschnitt hat die 9+0-Struktur der modifizierten Cilien mit zwei Basalkörpern. Im Plasma der Außenglieder sind nur Mikrotubuli zu erkennen. Die Außenglieder der Kontaktchemorezeptoren ziehen durch die röhrenförmige Dendritenscheide und den Kanal I des Haarschafts bis zu einem Porus in der Haarspitze, durch den sie mit den Schmeckstoffen in Kontakt kommen (Ort der Primärprozesse). Das Außenglied der Mechanorezeptorzelle enthält einen tubulären Körper und setzt an der Haarbasis an. Die Hüllzelle II (tormogene Zelle) bildet zum großen Sensillenlymphraum hin ein stark gefaltetes Membransystem aus. Der Feinbau wird in Beziehung zur Funktion der Schmeckhaare gesetzt.
    Notes: Summary The tarsal taste hairs of the blowfly contain five receptor cells: four contact chemoreceptors and one mechanoreceptor. These cells are surrounded concentrically by two sheath cells with fluid-filled spaces (“vacuoles”) between them. The receptor cell parts are the axon, the cell body, and the dendrite. The latter has an inner segment, a transitional region, and an outer segment. The transitional region shows the 9+0 configuration of a modified cilium with two basal bodies. In the outer segment only microtubules are found. The outer segments of contact chemoreceptors pass through the tube-like dendrite sheath, then through “canal I” of the hair shaft, to reach the pore at the tip of the hair. The outer segment of the mechanoreceptor contains a “tubular body” and terminates at the hair base. The “sheath cell II” (tormogene cell) forms a folded membrane system toward the main liquor space. The fine structure of the tarsal taste hairs is discussed in relation to their function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324812
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  • 10
    Electronic Resource
    Electronic Resource
    The subcellular localization of calcium in vertebrate smooth muscle: Calcium-containing and calcium-accumulating structures in muscle cells of mouse intestine (1976)
    Springer
    Cell & tissue research 169 (1976), S. 221-231 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Calcium ; Sarcoplasmic reticulum ; Mitochondria ; Microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intracellular localization of calcium by means of cytochemical techniques was studied in smooth muscle cells of mouse intestine. When the lead acetate method according to Carasso and Favard (1966) was used calcium was found in mitochondria and sarcoplasmic reticulum and occasionally between the myofilaments. The active ATP-dependent accumulation of calcium into cell structures was investigated by the oxalate method (Heumann and Zebe, 1967). After appropriate treatment the only structures of smooth muscle cells which contained calcium oxalate (identified by microprobe analysis) were elements of the sarcoplasmic reticulum. The results are discussed in relation to the role of calcium in the control of muscle activity during the contraction-relaxation cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214210
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