Journal ArticleDOI
Cell movement in intact and regenerating planarians. Quantitation using chromosomal, nuclear and cytoplasmic markers.
Emili Saló,Jaume Baguñà +1 more
Reads0
Chats0
TLDR
It is concluded that the so-called 'migration' of neoblasts is not a true cell migration but the result of the slow, even and progressive spreading of these cells mainly caused by random movements linked to cell proliferation.Abstract:
One of the tenets of Wolff and Dubois' 'neoblast theory' of planarian regeneration (Wolff & Dubois, 1948) is that blastema is mainly formed by the accumulation of undifferentiated parenchymal cells (neoblasts) that can migrate, if needed, over long distances to the wound. That neoblasts migrate was claimed by these authors after partial X-irradiation, and total X-irradiation and grafting using planarian strains of different pigmentation. From this they suggested that migration of neoblasts is stimulated by the wound and directed towards it. To study the nature and extent of such 'migration' in intact and regenerating organisms, and in order to avoid the flaws of using pigmentation as a marker, we made grafts between sexual and asexual races of Dugesia(S)mediterranea that differ in a chromosomal marker, and between diploid and tetraploid biotypes of Dugesia(S)polychroa that differ in nuclear size. Also, fluorescent latex beads were used as cytoplasmic markers to follow 'migration' of differentiated cells. The hosts were irradiated or non-irradiated intact and regenerating organisms. The results show that: 1) movement of graft cells into host tissues occurs in intact organisms at a rate of approximately equal to 40 micron/day, and that this increases up to approximately equal to 75 micron/day in irradiated hosts; 2) movement of cells occurs evenly in all directions; 3) regeneration does not speed up rate of movement nor drives cells preferentially to the wound; 4) spreading of cells is mainly due to the movement of undifferentiated cells (neoblasts); and 5) higher rates of movement are correlated with higher mitotic indexes. From this, it is concluded that the so-called 'migration' of neoblasts is not a true cell migration but the result of the slow, even and progressive spreading of these cells mainly caused by random movements linked to cell proliferation. The implications of these results for blastema formation and the origin of blastema cells are discussed.read more
Citations
More filters
Journal ArticleDOI
Fundamentals of planarian regeneration
TL;DR: The types of structures produced by blastemas on a variety of wound surfaces, the principles guiding the reorganization of pre-existing tissues, and the manner in which scale and cell number proportions between body regions are restored during regeneration are identified.
Journal ArticleDOI
Bromodeoxyuridine specifically labels the regenerative stem cells of planarians
TL;DR: The ability to label specifically the regenerative stem cells, combined with the recently described use of double-stranded RNA to inhibit gene expression in the planarian, should serve to reignite interest in the flatworm as an experimental model for studying the problems of metazoan regeneration and the control of stem cell proliferation.
Journal ArticleDOI
Role of Membrane Potential in the Regulation of Cell Proliferation and Differentiation
TL;DR: Understanding the molecular and mechanistic basis of biophysical regulation will point the way toward novel ways to rationally direct cell functions, allowing us to capitalize upon the potential ofBiophysical signaling for regenerative medicine and tissue engineering.
Journal ArticleDOI
Planarian regeneration involves distinct stem cell responses to wounds and tissue absence
TL;DR: In this article, the authors used the planarian Schmidtea mediterranea to study wound responses in regeneration initiation and found that there exist two functionally distinct signaling phases of the stem cell wound response that distinguish between simple injury and situations that require the regeneration of missing tissue.
Journal ArticleDOI
Regeneration and pattern formation in planarians: I. The pattern of mitosis in anterior and posterior regeneration in Dugesia (G) tigrina, and a new proposal for blastema formation
Emili Saló,Jaume Baguñà +1 more
TL;DR: The results obtained demonstrate that blastema formation in planarians occurs through mechanisms somewhat different to those shown to occur in the classical epimorphic models of regeneration, and suggest that planarian regeneration could represent an intermediate stage between morphallactic and epIMorphic modalities of regeneration.
References
More filters
Journal ArticleDOI
Regeneration and pattern formation in planarians: I. The pattern of mitosis in anterior and posterior regeneration in Dugesia (G) tigrina, and a new proposal for blastema formation
Emili Saló,Jaume Baguñà +1 more
TL;DR: The results obtained demonstrate that blastema formation in planarians occurs through mechanisms somewhat different to those shown to occur in the classical epimorphic models of regeneration, and suggest that planarian regeneration could represent an intermediate stage between morphallactic and epIMorphic modalities of regeneration.
Book ChapterDOI
Quantitative analysis of cell types during growth, degrowth and regeneration in the planarians Dugesia mediterranea and Dugesia tigrina
Jaume Baguñà,Rafael Romero +1 more
TL;DR: A method of tissue maceration (dissociation) of planarian tissues into single cells was used to characterize the basic cell types in the planarians Dugesia mediterranea and Dugesias tigrina and to determine the total cell number and distribution of cell types during growth, degrowth and regeneration.
Journal ArticleDOI
Sur la migration des cellules de régénération chez les Planaires
Étienne Wolff,F. Dubois +1 more
Journal ArticleDOI
Mitosis in the intact and regenerating planarian Dugesia mediterranea n.sp. II. Mitotic studies during regeneration, and a possible mechanism of blastema formation
TL;DR: It is suggested that neoblast proliferation could be under nervous tissue control through some stimulatory substance (s) released from the nerve terminals and the implications of this hypothesis for the maintenance of axial polarity are discussed.