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  • 1
    Electronic Resource
    Electronic Resource
    Vorticella: “A Cell For All Seasons” (1998)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 45 (1998), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1998.tb05102.x
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  • 2
    Electronic Resource
    Electronic Resource
    A Method for the Synchronous Induction of Large Numbers of Telotrochs in Vorticella convallaria by Monocalcium Phosphate at Low pH (1999)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 46 (1999), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We have devised a two step method for the synchronous induction of telotrochs in the peritrich ciliate, Vorticella convallaria. The method is easy, reliable, and allows us to study the earliest events of telotroch formation at the ultrastructural, biochemical, and molecular levels. The steps involved are: (1) excising the cell body from the stalk in a large population (7.4 times 104 cells) of EDTA-treated, attached cells by the application of monocalcium phosphate monohydrate solution at pH 3.2, (2) rinsing and suspending the isolated cell bodies in inorganic medium. Within 90 min, 80% of the population forms telotrochs. Analysis of factors that are important for maximum stalk excision and transformation shows that the population must not be older than 2 d and the most effective concentration of monocalcium phosphate is 4.8 mM for a 20 min exposure. The most effective monocalcium phosphate is in the monohydrated form. A pH value of 3.2, produced by the addition of hydrochloric acid in the presence or absence of calcium is not sufficient to initiate stalk excision and telotroch formation. This observation leads us to conclude that stalk excision is dependent on monocalcium phosphate or its hydrolysis products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1999.tb04574.x
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  • 3
    Electronic Resource
    Electronic Resource
    An Analysis of Macrostome Production in Tetrahymena vorax Strain V2S-Type (1966)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 13 (1966), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Tetrahymena vorax is a small polymorphic holotrichous ciliate capable of transforming to macrostomes when microstomes are washed and suspended with prey in distilled water.Extrinsic factors having an effect on this transformation were examined; maximum yields of macrostomes (in excess of 90%) were obtained under the following conditions: populations of both prey, T. pyriformis, and potential predator, T. vorax microstomes, were grown on Loefer's medium for 48 hours prior to washing in distilled water. The density of the prey was adjusted to 300,000 cells/ml and the predator density to 2,000–3,000 cells/ml. Five ml of prey suspension and 5 ml of T. vorax microstome suspension were mixed together in a large petri dish because a high surface-volume ratio is important for high yields of macrostomes. The pH was adjusted to 6.0 and the petri dish was placed at 20 C for 12 hr. Macrostomes then appeared about 6 hr after addition of the prey.A dialyzable, heat stable substance released by the prey which can induce the microstome-macrostome transformation was isolated. This material was effective after being stored for weeks in the cold; its activity was not affected by the protein digesting enzymes pepsin or trypsin. This factor was called stomatin because its first visible effect in producing microstome-macrostome transformation appeared to be to incite reorganization of the oral structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1966.tb01934.x
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  • 4
    Electronic Resource
    Electronic Resource
    Localization by Indirect Immunofluorescence of Tetrin, Actin, and Centrin to the Oral Apparatus and Buccal Cavity of the Macrostomal Form of Tetrahymena vorax (2004)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 51 (2004), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . We have taken advantage of the size of the macrostomal oral apparatus of Tetrahymena vorax to investigate the immunofluorescent localization of three cytoskeletal proteins—tetrin, actin, and centrin. Tetrin and actin antibodies co-localize to cross-connectives that anchor the membranelles. These antibodies also recognize the coarse filamentous reticulum, a filament associated with the undulating membrane. Actin-specific localization extends beyond the coarse filamentous reticulum-undulating membrane complex into a region called the specialized cytoplasm. A centrin antibody localizes to the fine filamentous reticulum which, along with micro-tubules of the oral ribs, circumscribes the cytostomal opening. Models of phagocytic contraction based on these data are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2004.tb00556.x
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of Vorticella convallaria calcium-binding centrin proteins (2005)
    Oxford, UK : Blackwell Science Inc
    The @journal of eukaryotic microbiology 52 (2005), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The stalked ciliate, Vorticella convallaria, is a good model system to study mechanochemical motility because its contractile organelles (spasmoneme and myonemes) use a mode of contraction that differs from most other eukaryotic motile systems. Since calcium triggers this contraction, we have undertaken the molecular characterization of the calcium-binding proteins associated with these organelles. We have isolated and identified seven unique centrin-like cDNAs from V. convallaria. Each encodes an acidic protein of approximately 20-kDa, containing a unique N-terminus and four potential calcium-binding domains. We predict that each centrin has a distinct function within the cell. To define these functions, we have initiated immunofluorescence localization studies utilizing various anti-centrin antibodies. Western analysis indicates that each antibody recognizes a distinct protein or subset of proteins in Vorticella. Using these antibodies, we have localized centrin to various structures within the cell; myonemes, spasmoneme, and the oral apparatus. Because each of these antibodies recognizes a different protein on Westerern analysis, we conclude that a number of calcium-binding proteins are associated with the contractile organelles. To further characterize this gene family, we have initiated immunolocalization at the ultrastructural level. This will permit subcellular localization of all Vorticella centrins and enable us to dissect the function of this multi-gene family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_1_43.x
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  • 6
    Electronic Resource
    Electronic Resource
    Microstome-Macrostome Transformation in Tetrahymena vorax Strain V2 Type S Induced by a Transforming Principle, Stomatin (1967)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 14 (1967), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Microstome →macrostome transformation in Tetrahymena vorax was induced by suspending microstomes in a transforming principle, stomatin, released by a potential prey, T. pyriformis. It was found that 70–90% of the microstomes formed macrostomes within 7 hours following suspension in this transforming principle. Macrostome formation occurred by the process of oral replacement. This process involved resorption of the microstome oral apparatus and its replacement with a larger (macrostome) one, which arose from an anarchic field that formed behind the resorbing oral area. Ninety-five percent of those microstomes which were destined to form macrostomes were in some stage of oral replacement 195 minutes after their suspension in stomatin. Several commercially produced products were tested over a wide range of concentrations to determine their ability to act as an inducer of macrostomes. Only 2, Trypticase and Bactocasitone, had any activity, and it was too small to be considered really effective. An attempt was also made to destroy the activity of stomatin by using enzymes. RNAse was effective but only in very high concentrations, so it was suggested that this activity might be related to the destruction of RNA within the transforming cell and not related to hydrolysis of stomatin. None of the other enzymes tested had any effect in reducing the activity of stomatin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1967.tb02049.x
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  • 7
    Electronic Resource
    Electronic Resource
    Analysis of centrin-, actin-, and tetrin-containing filaments in the Tetrahymena vorax macrostomal oral apparatus and their relation to the microtubule cytoskeleton (2005)
    Oxford, UK : Blackwell Science Inc
    The @journal of eukaryotic microbiology 52 (2005), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Our laboratory studies how the contractile cytoskeleton contributes to the process of phagocytosis. Because of its larger size and ease of manipulation, we chose the macrostomal cell of Tetrahymena vorax as our model for analysis of the distribution of proteins of prominent filamentous structures within the large oral apparatus (OA). Previous work in our laboratory identified centrin as a component of the fine filamentous reticulum (FFR) and actin and tetrin as colocalizing components of the coarse filamentous reticulum (CFR) and cross-connectives (CC) (J. Eukaryot. Microbiol., 51:253–257). Our new data also show that actin coimmunoprecipitates with tetrin proteins, confirming our actin–tetrin colocalization results. Because of its positioning around the cytostome, the actin-containing CFR/CC is a logical candidate for involvement in phagosome “pinch-off” following prey ingestion. We have analyzed this process by employing an assay that uses the addition of calcium to induce phagosome formation. We show that inhibitors of actin are able to block this event, indicating that actin is necessary for phagosome “pinch-off”. The OA also contains precisely arranged arrays of microtubules. We have examined the spatial relationship of the microtubular arrays to the distribution patterns of centrin, actin and tetrin, and found that tubulin and centrin fluorescences overlap in the region of the undulating membrane (UM). Tubulin fluorescence overlaps with actin and tetrin labeling at the inner edge of the CFR, where the CFR and UM converge. In addition to ciliary and oral rib labeling, tubulin antibodies also recognize the outer microtubule bundle (OMB), which delineates the right and posterior boundary of the OA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_1_58.x
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  • 8
    Electronic Resource
    Electronic Resource
    Cloning and Expression of a cDNA Encoding a Vorticella convallaria Spasmin: an EF-Hand Calcium-Binding Protein (1999)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 46 (1999), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The stalked, ciliated protozoan Vorticella convallaria possesses a highly contractile cytoskeleton consisting of spasmonemes and myonemes. The major component of these contractile organelles is the calcium-binding protein(s) called spasmin. Cloning and characterization of spasmin would help elucidate this contractile system. Therefore, enriched spasmoneme protein preparations from these contractile stalks were used to produce a monoclonal antibody to spasmin. A monoclonal antibody, 1F5, was obtained that immunolocalized specifically to the spasmonemes and the myonemes and recognized a 20-kD calcium-binding protein in spasmoneme protein preparations. A putative spasmin cDNA was obtained from a V. convallaria cDNA library and the derived amino acid sequence of this cDNA revealed an acidic, 20-kD protein with calcium-binding helix-loop-helix domains. The physical properties of the putative spasmin were assessed by characterization of a recombinantly-produced spasmin protein. The recombinant spasmin protein was shown to bind calcium using calcium gel-shift assays and was recognized by the anti-spasmin antibody. Therefore, a V. convallaria spasmin was cloned and shown to be a member of the EF-hand superfamily of calcium-binding proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1999.tb04601.x
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  • 9
    Electronic Resource
    Electronic Resource
    Symposium Introductory Remarks: “From Calcium-Binding Proteins to Contractile Organelles” (1998)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 45 (1998), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1998.tb05062.x
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  • 10
    Electronic Resource
    Electronic Resource
    The Fine Structure of the Scopula-Stalk Region of Vorticella convallaria (1997)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 44 (1997), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . We examined by SEM and TEM the stalk-scopular junction, the stalk, and stalk formation in Vorticella convallaria Linnaeus, 1767. The stalk sheath is anchored to the walls of the scopular lip and to the scopular cilia by thin fibrils. Experimental extraction of these fibrils weakens this junction enough to separate the stalk from the cell body. Telotrochs escape from the stalk by means of violent contractions of the cell body, accelerated beating of the trochal band cilia, and twisting of the cell body against the stalk. The edges of the scopular lip spread over the scopular cilia after escape and, in some cases, fuse to enclose the entire, aboral scopular surface in a cupola-like structure. The sessile cells contain fewer and smaller scopular granules than telotrochs. The presence of disintegrating scopular granules in the stalk matrix of some sessile cells suggests that they contain material which is secreted over a period of time to form the stalk. Eruptive formation of the initial adhesive pad and quick elongation of the distal part of the stalk suggests a rapid exocytosis of the larger, more numerous granules of the telotroch. The stalk sheath is formed of fibrils making up complete and incomplete compartments peripherally arranged along the major stalk axis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1997.tb05724.x
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