Studien über die Regeneration von Stylonychia mytilus

Dembowska, W. S.

doi:10.1007/bf02108498

Cited by 14 publications

(7 citation statements)

References 8 publications

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“…18-2 1) is obviously not completely identical in the two species because of the already mentioned differences in the arrangement of the posterior frontal cim and the transverse cim in the non-dividing specimens (Figs. 3,9). "True" transverse cim are formed at the posterior tip of the anlagen Development of the dorsal primordia.…”

Section: Cortical Development During Cell Divisionmentioning

confidence: 99%

Morphological, Biometric, and Morphogenetic Comparison of Two Closely Related Species, Stylonychia vorax and S. pustulata (Ciliophora: Oxytrichidae)1

Wirnsberger

Foissner

Adam

1985

The Journal of Protozoology

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Differences in the morphology of Stylonychia vorax Stokes, 1885 and S. pustulata (Müller, 1786) Ehrenberg, 1838 recognizable in vivo are the shape, the ventral cirral pattern, the caudal cirri, and the mode of moving. The dorsal‐bristle complexes are distinguishable by the length of dorsal kinety four and the spaces among the pairs of basal bodies. When the ranges of variation of different populations and clones are compared by biometric analyses, S. vorax shows a relatively stable cortical pattern whereas in S. pustulata the cortical elements are regulated depending on the size of the body and the number of adoral membranelles. In S. vorax morphogenesis begins with a proliferation of basal bodies close to the transverse cirri. In contrast, in S. pustulata, the oral primordium appears de novo between the left marginal row and the postoral cirri. All other morphogenetic events are the same for both species. In proters and opisthes the six anlagen of the frontal‐ventral‐transverse cirri are of different origin and evolve independently. Three anlagen of the opisthe separate from the oral primordium, two originate from the right, and one from the left postoral cirrus. Three anlagen of the proter evolve from the posteriormost cirrus in the frontal area, one from the parental undulating membranes, one from the buccal cirrus, and one from the cirrus below the buccal cirrus. The anlagen one to six generate one, three, three, three, four, and four cirri. The characteristic arrangement of the undulating membranes and the participation of only two postoral cirri in the formation of primordia provide features that distinguish between the often confused genera Oxytricha and Stylonychia.

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Section: Cortical Development During Cell Divisionmentioning

confidence: 99%

Morphological, Biometric, and Morphogenetic Comparison of Two Closely Related Species, Stylonychia vorax and S. pustulata (Ciliophora: Oxytrichidae)1

Wirnsberger

Foissner

Adam

1985

The Journal of Protozoology

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“…In addition, the remaining population (-24 cells) in the petri dish was at last fixed at 4 h (yielding 5 reorganizers). The second time, 7 reorganizers were collected from 76 cells (9%) during a 5.5-h starvation period: 3 cells were fixed at 1.5 h after the cell shape changed. The remaining population of about 70 cells was fixed at 3 h (yielding 4 reorganizers).…”

Section: Methodsmentioning

confidence: 99%

Physiological Reorganization and Post‐Traumatic Regeneration in Stylonychia mytilus: Reflections on Developmental Constraints and the Evolutionary Origin of Alternative Modes of Asexual Morphogenesis

Zou

1991

The Journal of Protozoology

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We investigated development of cortical ciliature in Stylonychia mytilus during starvation‐induced physiological reorganization, and during regeneration following amputation of the anterior part of the cell. Cortical reorganization in the two processes is generally similar. The posterior part of the adoral zone of membranelles is resorbed and replaced with newly assembled membranelles. The pre‐existing set of ventral cirri and dorsal bristles is entirely resorbed and replaced with new ones. Regenerants exhibit posterior displacement of the frontal‐ventral‐transverse cirri primordium and the undulating membrane primordium, and recruit basal bodies from ectopic locations for the development of these ciliature. This illustrates flexibility in the initiation site of ciliary primordia, and opportunism in utilizing building blocks. Such morphogenetic versatility of hypotrichs provides the basis for the operation of a global control of pattern formation, which governs cortical reorganization in dividers, and additionally, in the absence of the prerequisites for binary fission, alternative modes of cortical development such as physiological reorganization or regeneration. These considerations suggest that the three processes are homologous and that physiological reorganization and regeneration have evolved from binary fission. In physiological reorganization and regeneration, the micro‐ and macronuclei reorganize to resemble that in binary fission; these nuclear events are considered evolutionary relics of the nuclear development of binary fission. Tetrahymena also exhibits such morphogenetic flexibility; stomatogenesis is under global control, so that asexual cells can replace its oral apparatus without undergoing binary fission. Paramecium, on the other hand, adopts a more rigid strategy in relying heavily on pre‐existing structures for morphogenetic cues; this could have imposed constraints in the exploration of alternative modes of asexual development.

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“…There is an extensive literature indicating that quantitative regulation does occur, to bring about at least an approximate proportionality between the dimensions of the ciliary structures and the size of the whole cell, over an immense range of total cell volume. Dembowska showed in Stylonychia (33) and Tartar showed in Stentor (201) that tiny nucleated fragments, 1/100 or less of the typical cell volume, became normal both in shape and in ciliary pattern after regeneration. Proportional adjustments were also observed during the course of sequential spontaneous replacements of the ciliature.…”

Section: Properties Of the "Determinative Region"mentioning

confidence: 99%

“…If one pursues the problem of size-adjusted regulation to a finer level of detail, one perceives an important difference in conceptions of how such regulation is achieved. Dembowska (33,34) noted that development in diminutive stylonychias produced a normal number of major ventral cirri, but that each cirrus was of a reduced size, implying a reduction in both number and length of the cilia making up the cirri. Tartar, on the other hand, observing the adoral membranelle band of tiny stentors, concluded that the number of individual membranelles in each band became reduced but that the size of each membranelle remained the same (201, p. 120-123).…”

Section: Properties Of the "Determinative Region"mentioning

confidence: 99%