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  • 1
    Electronic Resource
    Electronic Resource
    Stomatogenesis in Resting Cysts of Colpodidae (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. The reorganization in resting cysts which produce a single emerging individual was followed in 5 species of Colpodidae forming a possible evolutionary series with increasing numbers of kineties. Stomatogenesis in Colpoda maupasi and C. inflata was studied for the first time; that in C. steinii, C. cucullus and Tillina magna was reinvestigated with new observations. In all, the oral primordium is double and originates from segments of certain somatic kineties, constant for each species. The larger mouthparts in the larger ciliates are produced from a correspondingly greater number of kineties. Morphogenetic and evolutionary implications of this series of observations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1966.tb01925.x
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  • 2
    Electronic Resource
    Electronic Resource
    Localization of Ciliary Primordia in Induced Abnormal Cysts of Oxytricha. fallax (1964)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 11 (1964), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Precystic organisms embedded in agar become abnormal cysts. Some of them are excystable rod-like or ellipsoid forms and the others, non-excystable fiat ones. Major axis of the rod-like or ellipsoid cysts is parallel with the body axis of the previous precystic organisms, because when the cysts are formed the protoplast within the secreted cyst walls rotates or agitates slightly around the major axis but movement around the minor axis is precluded.The fibrillar structures appearing in excystment from abnormal cysts are bilaterally symmetrical, different from the normal spherical cysts showing radial symmetry. The two poles from which the fibrils radiate are situated opposite each other but not at the extremities of the cyst. The locus of the anterior pole corresponds to the site of oral primordia in dividers and reorganizers.When the anterior part of the original adoral membranelles (AZM) in the early precystic animals is removed, the ellipsoid cysts from the abbreviated animals show a disturbance of the anterior fibrillar arrangement. The primoidium of the future AZM runs straight from the anterior extremity of the cyst toward the uninjured posterior pole. Ellipsoid cysts from precystic animals after the posterior region is removed similarly have disturbed fibrils near the posterior extremity of the cyst. The AZM primordium then arising on excystment extends from the uninjured anterior pole toward the damaged posterior extremity of the cyst. Similar events are found also in spherical cysts from anterior and posterior fragments of precystic animals.In either case, though the initial phase of the AZM primordium shows irregular contour, leaf-like shape is accomplished later accompanying the increase of primordial granules, while the other ciliary primordia such as undulating membrane and cirri arise at their corresponding areas. All can produce normal excysted animals.The ciliary primordia appearing upon excystment, notably that of the AZM, therefore seem to have descended from the precystic stage or foregoing trophic one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1964.tb01722.x
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  • 3
    Electronic Resource
    Electronic Resource
    Formation of Ciliature in Excystment and Induced Re-encystment of Oxytricha fallax Stein (1963)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 10 (1963), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. In excystment the primordium of adoral membranelles (AZM) arises as one granular row stretching meridionally toward the cortical axial poles, growing to several rows. Then the AZM's primordial granules become compactly aggregated with a leaf-like form. A separate primordium for the undulating membrane also appears as well as cirral primordia, all in arrangement similar to that in dividers and regenerators of the present species. Though it is difficult clearly to decide from where all these primordia are derived, their formation seems to have a morphogenetic relation to the thickening of certain fibrillar structures appearing only in resting cystic stages.Re-encystment is induced when the excysting cysts after the appearance of a contractile vacuole are transferred to Osterhout's solution from hay infusion employed for excystment induction. Re-encystment follows after the final step of excystment differentiation is accomplished but with aborted rupture of cyst walls. In the resulting re-encysted cyst, the secondary cyst walls are enclosed within the original ones. Repeated treatment can produce cysts with further supernumerary cyst walls by additional formation of third walls.Protoplasts in re-encystment show characteristics similar to animals prior to and after precystic stages. When their original cyst walls are removed, the naked protoplasts obtained take any one of the following courses: 1. recovery of normal form; 2. physiological regeneration; 3. irreversible encystment. Case (1) occurs in naked protoplasts from early stages of re-encystment; case (2), in those prior to the extrusion of excretory granules seen in the course of re-encystment; and the case (3), in those after their extrusion. From these results, presumably the removal of an incipient state of physiological regeneration in the course of re-encystment may be essential for dedifferentiation of the ciliature that redifferentiated fully in the preceding excystment without escapement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1963.tb01655.x
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  • 4
    Electronic Resource
    Electronic Resource
    Relationships between Feeding Organelles and Encystment in Oxytricha fallax Stein (1962)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 9 (1962), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. In Oxytricha fallax, extrusion of all the excretory crystals and some refractile bodies occurs when food is with held. The precystic animals thus resulting become transparent and undergo dedifferentiation of organelles. First the undulating membrane and cytostome are entirely resorbed, producing astomial forms. Then the adoral membranelles vanish gradually, accompanying which the somatic ciliature such as the cirri comes to be resorbed. Occasionally, early precystic animals retaining the intact feeding organelles reorganize spontaneously (physiological regeneration), but they become irreversibly encystable by high-temperature treatment; for hastening resorption of feeding organelles accelerates encystment.When transparent animals at various precystic stages are cut in half the posterior fragment (PF) always encysts faster than the anterior one (AF) from the same parent, except that some of the AFs from early stages reorganize into normal vegetative forms. The time difference for completion of encystment between an AF and PF pair is at early stages larger than at later ones. If the anterior part of AF is further excised, the time difference for encystment between AF and PF from the same source becomes smaller or indistinguishable, with the exception that some AFs from early stages regenerate instead. Further, when the anterior part of whole precystic animals is removed, the time for their encystment is reduced. Also in this case, the fragments from early stages normally regenerate.From these results, it is presumed that the adoral membranelles tend to inhibit the encystment process as they do the initiation of an oral primordium in dividers and regenerants of Stentor and other ciliates. Accordingly, when resorption of membranelles becomes extensive as precystic processes progress, their dominance over and inhibition of cyst formation may be diminishing. From the fact that regeneration of fragments from early stages into normal forms may be due to retention of the undulating membrane, its resorption is considered to be an essential prerequisite for the initiation of irreversible encystment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1962.tb02601.x
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  • 5
    Electronic Resource
    Electronic Resource
    Stomatogenesis and Formation of Cirri in Fragments of Oxytricha fallax Stein (1961)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 8 (1961), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Of fragments involving a partial removal of the original adoral zone of membranelles (AZM), the monomacro-nucleate ones become reorganized monostomes resulting from a simple fusion of the remnant AZM to the oral primordium induced, and the binucleate ones become dividers by initiation of the oral primordium posteriorly from the posterior terminal of the remnant AZM. The cirral primordium in any fragment arises alongside its corresponding oral area. Weisz's idea of the dominance and inhibition of the original oral system extending over the oral primordium site is applicable in stomatogenesis of the present species. This application is found also in cirral formation.In fragments from early stage dividers, a formed oral primordium is easily absorbed by influence of the intact original AZM. This event also occurs after complete removal of the AZM. Such results led to the hypothesis that the oral primordium in the normal divider may be formed under some stoma-togenic activation of the AZM followed by escape from inhibition also arising from the same source. Irrevocable furrow formation and irreversibility of the oral primordium in stomatogenesis occur in later stages of division. Nevertheless division in these stages is blocked when certain operations are performed, forming monsters possessing the AZM of the opisthe translocated to the side opposite to that of the proter. In other monsters obtained from a fusion of the AZM of the proter to that of the opisthe, division occurs belatedly, prior to which secondary oral and cirral primordia are produced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1961.tb01239.x
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