01834nas a2200217   4500008004100000020001400041245009100055210006900146260000800215300001200223490000700235520121100242100001501453700001601468700002201484700001401506700001701520700001601537700001701553856004601570       2009                        eng d  a0531-556500aThe free-living flatworm Macrostomum lignano: A new model organism for ageing research0 afreeliving flatworm Macrostomum lignano A new model organism for  cApr  a243-2490 v443 aTo study the several elements and causes of ageing, diverse model organisms and methodologies are required. The most frequently used models are Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster and rodents. All have their advantages and disadvantages and allow studying particular aspects of the ageing process. During the last few years, several ageing studies focussed on stem cells and their role in tissue homeostasis. Here we present a new model organism which can study this relation where other model systems fail. The flatworm Macrostomum lignano possesses a dynamic population of likely totipotent somatic stem cells known as neoblasts. Several characteristics qualify M. lignano as a suitable model system for ageing studies in general and more specifically for gaining more insight in the causal relation between stem cells, ageing and rejuvenation. In this review, we will briefly describe the species and its life history, and discuss the role of its stem cells in ageing and rejuvenation. We also give an overview of the available experimental tools that allow a multidisciplinary approach for studying ageing in M. lignano. (C) 2008 Elsevier Inc. All rights reserved.1 aMouton, S.1 aWillems, M.1 aBraeckman, B., P.1 aEgger, B.1 aLadurner, P.1 aScharer, L.1 aBorgonie, G.  uhttps://nematodes.myspecies.info/node/11502245nas a2200181   4500008004100000020001400041245008800055210006900143260000800212490000600220520170800226100001501934700001601949700001301965700002201978700001702000856004602017       2009                        eng d  a1742-999400aDemographic analysis reveals gradual senescence in the flatworm Macrostomum lignano0 aDemographic analysis reveals gradual senescence in the flatworm   cJul0 v63 aFree-living flatworms ("Turbellaria") are appropriate model organisms to gain better insight into the role of stem cells in ageing and rejuvenation. Ageing research in flatworms is, however, still scarce. This is partly due to culture difficulties and the lack of a complete set of demographic data, including parameters such as median lifespan and age-specific mortality rate. In this paper, we report on the first flatworm survival analysis. We used the species Macrostomum lignano, which is an emerging model for studying the reciprocal influence between stem cells, ageing and rejuvenation. This species has a median lifespan of 205 +/- 13 days (average +/- standard deviation [SD]) and a 90(th) percentile lifespan of 373 +/- 32 days. The maximum lifespan, however, is more than 745 days, and the average survival curve is characterised by a long tail because a small number of individuals lives twice as long as 90% of the population. Similar to earlier observations in a wide range of animals, in M. lignano the age-specific mortality rate increases exponentially, but levels off at the oldest ages. To compare the senescence of M. lignano with that of other ageing models, we determined the mortality rate doubling time, which is 0.20 +/- 0.02 years. As a result, we can conclude that M. lignano shows gradual senescence at a rate similar to the vertebrate ageing models Rattus norvegicus and Mus musculus. We argue that M. lignano is a suitable model for ageing and rejuvenation research, and especially for the role of stem cells in these processes, due to its accessible stem cell system and regeneration capacity, and the possibility of combining stem cell studies with demographic analyses.1 aMouton, S.1 aWillems, M.1 aBack, P.1 aBraeckman, B., P.1 aBorgonie, G.  uhttps://nematodes.myspecies.info/node/11602479nas a2200193   4500008004100000020001400041245008300055210006900138260000800207300001200215490000700227520192200234100001502156700001602171700001802187700001302205700002202218856004502240       2011                        eng d  a0531-556500aLack of metabolic ageing in the long-lived flatworm <i>Schmidtea polychroa</i>0 aLack of metabolic ageing in the longlived flatworm iSchmidtea po  cSep  a755-7610 v463 aFreshwater planarians have a large totipotent stem cell population allowing high rates of cell renewal and morphological plasticity. It is often suggested that they are able to rejuvenate during fission, regeneration and starvation. These features, together with the rapidly expanding molecular toolset, make planarians such as Schmidtea polychroa and S. mediterranea interesting for ageing research. Yet, the basic demographic and physiological data are lacking or still based on fragmentary observations of one century ago. Here, we present the first longitudinal physiological study of the species S. polychroa. Survival, size and metabolic rate, measured by microcalorimetry, of a cohort of 28 individuals were followed over a period of three years. Sexual maturity was reached during the second month after which the worms continued growing up to 5 months. This initial growth phase was followed by alternating periods of synchronised growth and degrowth. Although mass-specific metabolic rates declined during the initial growth phase, no changes were found later in life. The absence of metabolic ageing may be explained by the very high rate of cell renewal during homeostasis and alternating phases of degrowth and growth during which tissues are renewed. Surprisingly, all deaths occurred in pairs of worms that were housed in the same culture recipient, suggesting that worms did not die from ageing. Taking into account the metabolic and demographic data, we suggest that S. polychroa shows negligible ageing. Detailed analyses of size and metabolic rate revealed a remarkable biphasic allometric scaling relation. During the initial growth phase (months 1-5) the allometric scaling exponent b was 0.86 while later in life, it increased to an unusually large value of 1.17, indicating that mass-specific metabolic rate increases with size in adult S. polychroa. (C) 2011 Elsevier Inc. All rights reserved.1 aMouton, S.1 aWillems, M.1 aHouthoofd, W.1 aBert, W.1 aBraeckman, B., P.  uhttps://nematodes.myspecies.info/node/7900534nas a2200205   4500008004100000020001400041245004100055210004100096260000800137300001200145490000800157100001500165700001700180700001600197700001500213700001500228700002200243700001800265856004500283       2010                        eng d  a0777-627600aEstablishing a flatworm ageing model0 aEstablishing a flatworm ageing model  cJul  a195-1970 v1401 aMouton, S.1 aVerdoodt, F.1 aWillems, M.1 aDhondt, I.1 aCrucke, J.1 aBraeckman, B., P.1 aHouthoofd, W.  uhttps://nematodes.myspecies.info/node/9301303nas a2200193   4500008004100000020001400041245012400055210006900179300001200248490000700260520069400267100001700961700002200978700001701000700001301017700001801030700001601048856004501064       2011                        eng d  a1388-554500aThe importance of feeding status and desiccation rate in successful anhydrobiosis of <i>Panagrolaimus detritophagus</i>0 aimportance of feeding status and desiccation rate in successful   a185-1910 v133 aWe examined the effect of nutritional status and desiccation rate on the ability of Panagrolaimus detritophagus to undergo anhydrobiosis, as well as to survive high temperatures in the dried state. Both nutrition and drying rate were found to be important, with starvation and slow drying providing better success at anhydrobiosis. The upper temperature for survival of dried animals in laboratory studies was 80 degrees C. Starved worms recovered from drying more successfully when the starvation period was followed by a smooth, gradual dry period prior to undergoing desiccation. Thus, the ability of these worms to enter and leave anhydrobiosis is dependent on critical stress signals.1 aSalehian, S.1 aBraeckman, B., P.1 aBeladjal, L.1 aBert, W.1 aClegg, J., S.1 aMertens, J.  uhttps://nematodes.myspecies.info/node/77