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Regeneration in Macrostomum lignano (Platyhelminthes): cellular dynamics in the neoblast stem cell system

Institute of Zoology, University of Innsbruck, Technikerstrasse 25, Innsbruck 6020, Austria.
Cell and Tissue Research (Impact Factor: 3.33). 04/2007; 327(3):637-46. DOI: 10.1007/s00441-006-0299-9
Source: PubMed

ABSTRACT Neoblasts are potentially totipotent stem cells and the only proliferating cells in adult Platyhelminthes. We have examined the cellular dynamics of neoblasts during the posterior regeneration of Macrostomum lignano. Double-labeling of neoblasts with bromodeoxyuridine and the anti-phospho histone H3 mitosis marker has revealed a complex cellular response in the first 48 h after amputation; this response is different from that known to occur during regeneration in triclad platyhelminths and in starvation/feeding experiments in M. lignano. Mitotic activity is reduced during the first 8 h of regeneration but, at 48 h after amputation, reaches almost twice the value of control animals. The total number of S-phase cells significantly increases after 1 day of regeneration. A subpopulation of fast-cycling neoblasts surprisingly shows the same dynamics during regeneration as those in control animals. Wound healing and regeneration are accompanied by the formation of a distinct blastema. These results present new insights, at the cellular level, into the early regeneration of rhabditophoran Platyhelminthes.

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    • "During anterior regeneration, pax-6 has been shown to be expressed in the developing central nervous system and ocelli (Loosli et al., 1996), otx is expressed in the developing central nervous system but not ocelli (Charpignon, 2007), and vision-related six and opsin genes are expressed in the brain and ocelli (Charpignon, 2007). "
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    The International Journal of Developmental Biology 12/2014; 58:623 - 634. DOI:10.1387/ijdb.140142ab
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    • "In M. lignano, the presence of a population of fast-cycling neoblasts has been described, additional to the main population of cycling neoblasts (Nimeth et al., 2007). These fast-cycling cells cycle through the whole S, and G2-phase in just 2 h. "
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    ABSTRACT: Platyhelminthes are highly attractive models for addressing fundamental aspects of stem cell biology in vivo. These organisms possess a unique stem cell system comprised of neoblasts that are the only proliferating cells during adulthood. We have investigated Ts (S-phase duration) of neoblasts during homoeostasis and regeneration in the flatworm, Macrostomum lignano. A double immunohistochemical technique was used, performing sequential pulses with the thymidine analogues CldU (chlorodeoxyuridine) and IdU (iododeoxyuridine), separated by variable chase times in the presence of colchicine. Owing to the localized nature of the fluorescent signals (cell nuclei) and variable levels of autofluorescence, standard intensity-based colocalization analyses could not be applied to accurately determine the colocalization. Therefore, an object-based colocalization approach was devised to score the relative number of double-positive cells. Using this approach, Ts (S-phase duration) in the main population of neoblast
    International Journal of Cell Biology 12/2011; 36:1251-1259. DOI:10.1042/CBI20120187
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    • "Our research focuses on the stem cell system of the flatworm Macrostomum lignano (Ladurner et al. 2005, 2008). Recent work on this species has demonstrated the advantage of M. lignano for studying stem cell biology and regeneration (Ladurner et al. 2000, 2008; Pfister et al. 2008; Nimeth et al. 2007; Pfister et al. 2007; Egger et al. 2006; De Mulder et al. 2009). The detailed morphological knowledge and transparency of M. lignano provides the opportunity to analyse the effects of various stress conditions at a morphological level. "
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    ABSTRACT: Stem cells are the only proliferating cells in flatworms and can be eliminated by irradiation with no damage to differentiated cells. We investigated the effect of fractionated irradiation schemes on Macrostomum lignano, namely, on survival, gene expression, morphology and regeneration. Proliferating cells were almost undetectable during the first week post-treatment. Cell proliferation and gene expression were restored within 1 month in a dose-dependent manner following exposure to up to 150 Gy irradiation. During recovery, stem cells did not cross the midline but were restricted within lateral compartments. An accumulated dose of 210 Gy resulted in a lethal phenotype. Our findings demonstrate that M. lignano represents a suitable model system for elucidating the effect of irradiation on the stem cell system in flatworms and for improving our understanding of the recovery potential of severely damaged stem-cell systems. Electronic supplementary material The online version of this article (doi:10.1007/s00441-009-0915-6) contains supplementary material, which is available to authorized users.
    Cell and Tissue Research 03/2010; 339(3):527-42. DOI:10.1007/s00441-009-0915-6
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