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  • 1
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Schlinger Pseudomicrothorax dubius ingestiert innerhalb von 1–2 min ein großes Volumen fädiger Blaualgen. Die Nahrung ist unmittelbar nach dieser rapiden Phagocytose in einer einzigen, sehr großen Vakuole eingeschlossen, die fast den ganzen Ciliaten ausfüllt. Im Verlaufe der folgenden Stunde vesikuliert diese große Nahrungsvakuole über Zwischenstufen zu einer Vielzahl von Vakuolen mit 1–2 μm Durchmesser. Gleichzeitig erfolgt eine Kondensierung des Vakuoleninhaltes. Erst zu diesem Zeitpunkt setzt die Verdauung der Nahrung ein, wie an Hand von zahlreichen Dictyosomen belegt wird, die nun in unmittelbarer Nähe der Nahrungsvakuolen nachzuweisen sind. Durch die Vesikulation der großen Nahrungsvakuole in kleinere Einheiten sowie durch die Kondensierung der Nahrung wird bewirkt, daß die über Lysosomen in die Nahrungsvakuolen abgegebenen Verdauungsenzyme optimal eingesetzt werden. Nach Beendigung der Verdauung liegen viele leere Vakuolen vor, die durch eine stark gefaltete Kontur gekennzeichnet sind. Diese Vakuolen gehen allem Anschein nach wieder in den Membranhaushalt der Zelle ein.
    Notes: Summary The gulper Pseudomicrothorax dubius ingests a large volume of filamentous blue-green algae within 1–2 min. Immediately after this rapid phagocytosis, the food is enclosed in a single, extremely large food vacuole, which fills up the ciliate almost entirely. During the following hour this giant food vacuole vesiculates. Finally numerous small vacuoles are present, 1–2 μm in diam. Simultaneously the content of the vacuoles is noticeably condensed. At this time the digestion of the food starts as is indicated by numerous dictyosomes, which now surround the periphery of the food vacuoles. Due to both, the prior vesiculation of the food vacuole and the condensation of the food, the digestive enzymes can act very effectively. After 6–8 hours, when the digestion of the food is finished, numerous empty vacuoles are found. Each is characterized by a highly irregular, convoluted outline. Apparently these vacuoles are eventually recycled to the membrane pool of the cell.
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  • 2
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phagocytosis and digestion in Climacostomum virens were investigated using the flagellate Chlorogonium elongatum as food. The flagellates are pushed through the buccal tube to be enclosed in food vacuoles in the cytopharyngeal region at the base of the buccal tube. Cytopharyngeal vesicles contribute membrane to the forming food vacuoles. Within 3–5 min after ingestion, small vesicles, presumably primary lysosomes, surround the food vacuole and fuse with it. Electron-lucent folds develop in the food vacuole membrane 3–6 h after feeding. Electron dense evaginations from the vacuole are detected 9–24 h after ingestion. Folds and evaginations appear to be involved in the resorption and transport of digested material through the cytoplasm. Defecation of undigested residues at the cytoproct occurs 12–24 h after ingestion. The membrane of the defecation vacuole fragments to form numerous vesicles as the undigested residues are discharged.
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  • 3
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Es wird von monströsem Wachstum beim CiliatenPseudomicrothorax dubius berichtet, der die CyanophyceeOscillatoria formosa frißt. Die Ciliatenmonster treten vorwiegend dann auf, wenn die Algenfäden, die einen aggregierten oder einen gespreiteten Zustand einnehmen können, sich in der Spreitungsphase befinden. Die Spreitung und damit das Monsterwachstum können durch Verwendung von Petrischalen aus Plastik beschleunigt hervorgerufen werden. Die Spreitung tritt, wie experimentell abgeklärt wurde, infolge des Kontaktes der Algenfäden mit dem Plastiksübstrat ein. Durch Zusatz des Detergens Tween 80 kann diese Spreitung rückgängig gemacht werden. Die Rolle des Plastikmaterials und die der Algen wird hinsichtlich des Monsterwachstums diskutiert.
    Notes: Summary This paper deals with the monstrous growth of the blue-green algae feeding ciliatePseudomicrothorax dubius. The monstrous ciliates mainly appear, when the feed algae (Oscillatoria formosa), which can be found either in an aggregated or in an extended state, are spread. The spreading and with it the monstrous growth can be hastened by the use of Petri dishes made of plastic. The spreading chiefly occurs in consequence of the contact between algae and plastic. The application of the detergent Tween 80 effects a decline of this spreading. The role of the plastic and the algae is discussed with regard to the monstrous growth.
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  • 4
    ISSN: 1615-6102
    Keywords: Antibiotics ; Bacterial adhesion ; Devescovina glabra ; Ectobiote ; Flagellate ; Joenia annectens ; Lectin ; Microrhopalodina multinudeata ; Stephanonympha nelumbium ; Termite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many of the flagellates inhabiting the hindgut of lower termites are associated with ectobiotic, rod-like bacteria or spirochetes. Different types of attachment sites are present. Electron dense material underlies, e.g., the plasma membrane ofJoenia annectens at the contact site, whereas other attachment sites do not show any visible specializations. The host cell's glycocalyx may, however, be reduced at the attachment sites as it is the case inDevescovina glabra. The thick glycocalyx ofStephanonympha nelumbium is not changed at the sites where bacterial rods attach, but spirochetes penetrate to a certain extent. Bacteria which colonize the extracellular surface structures ofMicrorhopalodina multinucleata express their own glycocalyx to mediate a contact. In this study we focussed on the examination of one common mode of interaction between bacteria and their host cells, i.e., adhesion via lectins and sugars. The sugar composition was analysed by light and electron microscopic labelling experiments using the lectins Con A, WGA and SBA. In general, only the posterior body surface ofJoenia which is colonized with bacteria is labelled. The demonstrated sugars are found in fibrous glycocalyx portions surrounding the attachment sites of the bacteria. Such glycocalyx fibres in combination with the electron dense material supporting the attachment sites seem to be the prerequisites for bacterial attachment. InD. glabra, however, a role for sugars in mediating the attachment could not be demonstrated. Removal of the ectobiotes using antibiotics revealed that the specialized contact sites ofJoenia are present in the absence of bacteria and thus possibly serve to attract bacteria. Nothing, however, remains of the former attachment sites in bacteria-freeDevescovina cells. Attachment sites in this case could be induced by bacterial contact. There is not one general mechanism for bacterial attachment to termite flagellates; rather, adhesion seems to follow different strategies.
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  • 5
    ISSN: 0886-1544
    Keywords: amoebae ; actinopoda ; heliozoa ; Actinophrys ; phagocytosis ; pseudopodia ; membrane ; extrusomes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two phases of prey capture by the heliozoon Actinophrys sol are documented by electron microscopy. The phases are those of prey adhesion to the predator and enclosure of the prey by the predator. Adherence is brought about by numerous small pieces of adhesive membrane produced by the predator at the site of prey contact. Some of the heliozoan extrusomes expel their contents at this time, but the significance of this event is unclear. Enclosure of the prey is effected by a funnelshaped pseudopodium. This is drawn over the prey by the action of the leading margin. The ultrastructural appearance of the cytoplasm of the leading margin differs from the rest of the cell, being homogeneous and finely filamentous. Both force and traction for the progression of the pseudopod are generated primarily at the tip. During the development of the funnel-pseudopod, extrusomes expand and fuse with each other and with the plasma membrane. Their investing membrane is thereby made available as food vacuole membrane.
    Additional Material: 9 Ill.
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  • 6
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Stephanonympha nelumbium is a large trichomonad measuring 45–60 μm in length and 20–40 μm in width. It is a member of the multinucleate and multiflagellate family Calonymphidae. While the numerous flagella arise in groups of four at the anterior cell pole, the posterior body portion is covered with attached spirochetes and rod-like bacteria. Generally, in the apical body portion of S. nelumbium, 50–100 nuclei are arranged in five to seven circular rows. Each nucleus is associated with a typical mastigont system, comprised of three anterior flagella, one recurrent flagellum being attached to the cell surface for a certain distance, and several typical root structures. Akaryomastigonts and costas do not occur. The fine structure of S. nelumbium corresponds with that of other calonymphids. The main difference to Calonympha is that the axostyle does not embrace the nucleus but passes it in form of a flattened rod.
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  • 7
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The nuclei of trophozoites and digestive cysts as well as mitotic nuclei of several species of the vampyrellids Vampyrella, Gobiella, Hyalodiscus, Arachnula, and Leptophrys were investigated by electron microscopy. Except for some species of the genus Hyalodiscus, the vampyrellids are generally multinucleate. The nuclei of the trophozoite stage are in interphase. These nuclei are spherical, except for the genus Arachnula, which reveals elongated nuclei. In digestive cysts of all vampyrellids the nuclei enlarge and the pars granulosa of the nucleoli becomes prominent. Karyokineses take place synchronously in older digestive cysts, which transform into reproductive cysts. The nuclei divide by closed intranuclear orthomitosis. In telophase the old nuclear envelope disintegrates and a new one is rearranged. Only in the genus Leptophrys the nuclear envelope decomposes before telophase. Neither centrioles nor MTOC-plaques have been found in any stage of mitosis. After karyokinesis the cell divides inside the cyst or when leaving the cyst.
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  • 8
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The nuclear apparatus of H. vermiculare consists of a single moniliform macronucleus and about 25 micronuclei. the micronuclei are about 3 μm in diameter and characterized by a meshwork of thick condensed chromatin. Mitosis is intranuclear and acentric as in all other ciliates. In metaphase, interpolar and chromosomal microtubules are abundant and the length of the micronuclei increases to about 5 μm. In late anaphase, interzonal microtubules become prominent and the spindle elongates to about 50 μ. In meta- and anaphase, the microtubules of the spindle are attached to the polar vesicles, and in anaphase, chromosomes become attached to it. In contrast to most other eukaryotes, micronuclear mitosis is not strictly bound to cell division in H. vermiculare. While most of the micronuclei divide prior to cytokinesis, others retain their interphasic shape or degenerate. In addition, some micronuclei divide in the interdivision period, i.e. between two successive divisions of the cell and macronucleus. Mating cells of H. vermiculare become joined to each other in the cilia-free region covering the cytostome. In the course of conjugation, the cell membranes and the underlying oral filamentous sheaths of both cells fuse, thus uniting the endoplasm of both cells in the mouth region. Synaptonemal complexes in the meiotic chromosomes are more distinct in H. vermiculare than in most other dilates. the micrographs presented here depict dearly the central filament, transverse elements, and other substructures.
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  • 9
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The nuclear apparatus of Homalozoon vermiculare consists of a single moniliform macronucleus and about 25 micronuclei. The number of macronuclear segments depends (i) on the number of divisions of individual segments during the interphase and (ii) on the number of segments that arise prior to cytokinesis from the (temporary) filiform macronucleus. Precytokinetic changes of the macronucleus involve the fusion of individual segments followed by contraction and subsequent elongation of the entire macronucleus. The chromatin bodies uncoil into fine fibrils during macronuclear contraction. At the time when the division furrow appears, the macronucleus starts to renodulate. The interphase segment contains a more or less reticulated chromatin body partly attached to the nuclear envelope and about 30 polymorphous nucleoli. The latter consist of the pars granulosa, the pars fibrosa, and an additional fibrillar component. The nucleoli undergo drastic changes prior to division and the granular component disappears completely during macronuclear condensation. On the average, the macronucleus contains a 3,400-fold amount of DNA compared with a haploid micronucleus, but the intraspecific differences in the DNA content of the entire macronucleus are extremely large. In contrast, DNA content and size of an individual segment of the macronucleus are precisely regulated during interphase.
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  • 10
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The ultrastructure of the cortex of Homalozoon vermiculare is described. The ventral side bears 13–15 iongitudinal kineties composed of monokinetids. On the dorsal surface, there are 3 kineties, 2 of which are composed of dikinetids in the anteriormost part of the cell. Consequently there exist 3 different kinds of kinetids within the somatic cortex: 1) The monokinetids on the ventral side are associated with a kinctodesmal fibril, 2 transverse microtubular ribbons and 7 postciliary microtubules in a double-row configuration; 2) The monokinetids on the dorsal side are very similar but they are associated with just 3 very ‘short postciliary microtubules; 3) The posterior kinetosome of the dorsal dikinetids bears the same fibrillar associates as the dorsal monokinetid, but it lacks the second transverse ribbon. The anterior kinetosome of each pair is associated with a single postciliary’ microtubule. The kinetid organization of Homalozoon is compared to that of other members of the Haptorida. Their phylogeny is discussed. A monophyleiic taxon within the litostomate ciliates is characterized by data on the somatic kinetids, and the new subclass Ditransversalia n. subcl. is constituted. The new subclass comprises the genera Balantidium, Bryophyllum, Enchelydium, Homalozoon, Isotricha, Lacrymaria, Lepidolrachelophyllum, Spathidium and Vestibulongum.
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