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Sample records for planarians platyhelminthes tricladida

  1. First report of the land planarian Diversibipalium multilineatum (Makino & Shirasawa, 1983) (Platyhelminthes, Tricladida, Continenticola) in Europe.

    PubMed

    Mazza, Giuseppe; Menchetti, Mattia; Sluys, Ronald; Solà, Eduard; Riutort, Marta; Tricarico, Elena; Justine, Jean-Lou; Cavigioli, Luca; Mori, Emiliano

    2016-01-01

    Introduction of alien species may significantly affect soil ecosystems, through predation or disruption of components of native ecosystems (Winsor et al. 2004; Álvarez-Presas et al. 2014; Justine et al. 2014). Land planarians have been reported as alien species in soils throughout the world and, among those, some species are considered to be successful invaders, e.g. Platydemus manokwari de Beauchamp, 1963, Arthurdendyus triangulatus (Dendy, 1894), Bipalium adventitium Hyman, 1943, Bipalium kewense Moseley, 1878 and Dolichoplana striata Moseley, 1877 (Winsor et al. 2004; Álvarez-Presas et al. 2014; Justine et al. 2014, 2015). Soil moisture status seems to be an important element for their successful invasion (Fraser & Boag 1998). In Europe at least 18 species of alien land planarians have been recorded since now and some of them are considered as invasive ones, e.g. P. manokwari (cf. Justine et al. 2014). Although the alien land planarian B. kewense has been reported to occur in many greenhouses in Italy (Bello et al. 1995), no data are available on its establishment and/or impact on natural environments. On 28th September 2014, 20 specimens (~1 individual/m2) of the land planarian Diversibipalium multilineatum (Makino & Shirasawa, 1983) (Fig. 1), native to Japan, were collected under pots, branches and plastic materials in a private garden located in the center of Bologna (Emilia Romagna, Central Italy), near the urban park Giardini Margherita (44°29' N, 11°21' E; WGS84). Thirty plant species (both indigenous and alien), mainly cultivated as bonsai (e.g. Lagerstroemia indica L., Juniperus procumbens (Siebold ex Endl.) Miquel), were present in this shady, wet garden (25 m2). Between March 2014 and June 2015, 70 more specimens of D. multilineatum were collected at the same site, mainly at dusk and dawn after rain. Reproduction by fission and regeneration processes were observed in several of those specimens, which were kept for

  2. Evolutionary history of the Tricladida and the Platyhelminthes: an up-to-date phylogenetic and systematic account.

    PubMed

    Riutort, Marta; Álvarez-Presas, Marta; Lázaro, Eva; Solà, Eduard; Paps, Jordi

    2012-01-01

    Within the free-living platyhelminths, the triclads, or planarians, are the best-known group, largely as a result of long-standing and intensive research on regeneration, pattern formation and Hox gene expression. However, the group's evolutionary history has been long debated, with controversies ranging from their phyletic structure and position within the Metazoa to the relationships among species within the Tricladida. Over the the last decade, with the advent of molecular phylogenies, some of these issues have begun to be resolved. Here, we present an up-to-date summary of the main phylogenetic changes and novelties with some comments on their evolutionary implications. The phylum has been split into two groups, and the position of the main group (the Rhabdithophora and the Catenulida), close to the Annelida and the Mollusca within the Lophotrochozoa, is now clear. Their internal relationships, although not totally resolved, have been clarified. Tricladida systematics has also experienced a revolution since the implementation of molecular data. The terrestrial planarians have been demonstrated to have emerged from one of the freshwater families, giving a different view of their evolution and greatly altering their classification. The use of molecular data is also facilitating the identification of Tricladida species by DNA barcoding, allowing better knowledge of their distribution and genetic diversity. Finally, molecular phylogenetic and phylogeographical analyses, taking advantage of recent data, are beginning to give a clear picture of the recent history of the Dugesia and Schmidtea species in the Mediterranean. PMID:22450992

  3. Anatomical deviation of male organs of land planarians from Rio de Janeiro, Brazil, with description of two new species of Cratera (Platyhelminthes, Tricladida).

    PubMed

    Carbayo, Fernando

    2015-01-01

    Two new land planarian species, collected in the State of Rio de Janeiro, Brazil, are described. Their external aspect is similar to that of Imbira marcusi Carbayo et al., 2013 and Pseudogeoplana theresopolitana (Schirch, 1929), respectively. The analysis of the internal organs, however, revealed they belong to the genus Cratera. The male copulatory organs of one species is very different from any other geoplaninid, for the penis papilla holds a large, distal cavity receiving the ejaculatory duct and, furthermore, the papilla projects vertically downwards from the roof of the male atrium. Thus we consider it as a new species, Cratera cuarassu sp. nov. The second species differs from its congeners in that the dorsal insertion of the penis papilla is anterior to the ventral one, and in that the female atrium is narrowed in the anterior portion. The species was found in the type locality of Pseudogeoplana theresopolitana (Schirch, 1929) and compares well with it in the external features. However, since its internal organs are unknown and the type material of the species is seemingly lost, we describe it as Cratera anamariae Carbayo, sp. nov. PMID:25781812

  4. Integrative taxonomy of a new species of planarian from the Lake Ohrid basin, including an analysis of biogeographical patterns in freshwater triclads from the Ohrid region (Platyhelminthes, Tricladida, Dugesiidae)

    PubMed Central

    Stocchino, Giacinta Angela; Sluys, Ronald; Deri, Paolo; Manconi, Renata

    2013-01-01

    Abstract A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of the Balkan Peninsula, forming the first fully documented species description for this genus in the Ohrid area. The morphological species delimitation is supported by complementary molecular, karyological, and cytogenetic data available from the literature. Therefore, species delineation is based on a truly integrative approach. Further, a short account on the degree of freshwater planarian endemicity in the Ohrid region is provided. PMID:23840163

  5. Integrative taxonomy of a new species of planarian from the Lake Ohrid basin, including an analysis of biogeographical patterns in freshwater triclads from the Ohrid region (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Stocchino, Giacinta Angela; Sluys, Ronald; Deri, Paolo; Manconi, Renata

    2013-01-01

    A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of the Balkan Peninsula, forming the first fully documented species description for this genus in the Ohrid area. The morphological species delimitation is supported by complementary molecular, karyological, and cytogenetic data available from the literature. Therefore, species delineation is based on a truly integrative approach. Further, a short account on the degree of freshwater planarian endemicity in the Ohrid region is provided. PMID:23840163

  6. The complete mitochondrial genome of Dugesia japonica (Platyhelminthes; order Tricladida).

    PubMed

    Sakai, Masato; Sakaizumi, Mitsuru

    2012-10-01

    We used two sequencing methods, namely long polymerase chain reaction (PCR) and primer walking, to determine the complete mitochondrial DNA (mtDNA) sequence of Dugesia japonica and most of the mtDNA sequence of Dugesia ryukyuensis. The genome of D. japonica contained 36 genes including 12 of the 13 protein-coding genes characteristic of metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. The genome of D. ryukyuensis contained 33 genes, including 12 protein-coding genes, two ribosomal RNA genes, and 19 transfer RNA genes. The gene order of the mitochondrial genome from the Dugesia species showed no clear homology with either the Neodermata or other free-living Rhabditophora. This indicates that the platyhelminths exhibit great variability in mitochondrial gene order. This is the first complete sequence analysis of the mitochondrial genome of a free-living member of Rhabditophora, which will facilitate further studies on the population genetics and genomic evolution of the Platyhelminthes. PMID:23030340

  7. Investigation of the ultrastructure of Dendrocoelum constrictum (Platyhelminthes, Tricladida) spermatogenesis and mature spermatozoa.

    PubMed

    Harrath, Abdel Halim; Gammoudi, Mehrez; Mansour, Lamjed; Ahmed, Mukhtar; Sirotkin, Alexander V; Al Omar, Suliman Y; Ibrahim, Khalid E; Alwasel, Saleh H

    2014-09-01

    To add to our understanding of dendrocoelid spermatozoa and to describe additional phylogenetic characters, the ultrastructure of the testis was investigated in the subterranean freshwater planarian Dendrocoelum constrictum. This is the first study investigating spermatogenesis and spermatozoon ultrastructure in a subterranean freshwater planarian species. We found that the basic structure of spermatozoa in D. constrictum is similar to that of other Tricladida that have been studied previously. In fact, D. constrictum spermatozoa possess an elongated nucleus, one giant mitochondrion, and two subterminal flagella with a 9+'1' pattern. The flagella emerge together from one side of the spermatozoon. However, D. constrictum has some characteristics that have not yet been described for other freshwater planarians. In fact, the number of cortical microtubules reaches the maximum number in the anterior and middle part of region I, and then decrease until they disappear towards the posterior extremity of the spermatozoon. The extreme tip of the anterior region of the spermatozoon exhibits a specific external ornamentation of the plasma membrane. PMID:25242690

  8. The power of regeneration and the stem-cell kingdom: freshwater planarians (Platyhelminthes).

    PubMed

    Saló, Emili

    2006-05-01

    The great powers of regeneration shown by freshwater planarians, capable of regenerating a complete organism from any tiny body fragment, have attracted the interest of scientists throughout history. In 1814, Dalyell concluded that planarians could "almost be called immortal under the edge of the knife". Equally impressive is the developmental plasticity of these platyhelminthes, including continuous growth and fission (asexual reproduction) in well-fed organisms, and shrinkage (degrowth) during prolonged starvation. The source of their morphological plasticity and regenerative capability is a stable population of totipotent stem cells--"neoblasts"; this is the only cell type in the adult that has mitotic activity and differentiates into all cell types. This cellular feature is unique to planarians in the Bilateria clade. Over the last fifteen years, molecular studies have begun to reveal the role of developmental genes in regeneration, although it would be premature to propose a molecular model for planarian regeneration. Genomic and proteomic data are essential in answering some of the fundamental questions concerning this remarkable morphological plasticity. Such information should also pave the way to understanding the genetic pathways associated with metazoan somatic stem-cell regulation and pattern formation. PMID:16615086

  9. Fine-scale differences in diel activity among nocturnal freshwater planarias (Platyhelminthes: Tricladida)

    PubMed Central

    2011-01-01

    Background Although most freshwater planarias are well known photonegative organisms, their diel rhythms have never been quantified. Differences in daily activity rhythms may be particularly important for temperate-climate, freshwater planarias, which tend to overlap considerably in spatial distribution and trophic requirements. Methods Activity of stress-free, individually tested young adults of three common planarian species was recorded at 3-h intervals in a 10-d experiment under natural sunlight and photoperiod during autumnal equinox (D:L ~12:12). Individual activity status was averaged over the 10-d experiment, each tested individual thus serving as a true replicate. Twelve individuals per species were tested. Food was provided every 36 h, resulting in alternating day- and nighttime feeding events. Activity during the first post-feeding h was recorded and analyzed separately. Statistical procedures included ANOVAs, correlations, and second-order analyses of angles. Results Dugesia (= Girardia) tigrina Girard 1850 exhibited clear nocturnal behavior, Dugesia (= Schmidtea) polychroa Schmidt 1861 was predominantly but not exclusively nocturnal, and Polycelis tenuis Ijima 1884 was relatively more active from midnight through noon. Species-specific activity peaks were statistically similar, with peaks at dawn for P. tenuis and just before midnight for the two dugesiids; however, D. tigrina was comparatively more active in the early night hours, while D. polychroa was more active than D. tigrina during daytime. D. tigrina also responded less readily to daytime food addition. P. tenuis remained poorly active and unresponsive throughout the experiment. Individual variability in diel behavior was highest for D. polychroa and lowest for D. tigrina. P. tenuis's general low degree of activity and late activity peak in the experiment may be related to a strong reliance on external stimuli. Conclusions The tested species are mainly nocturnal, consistent with their

  10. Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida)

    NASA Astrophysics Data System (ADS)

    Iwai, Noriko; Sugiura, Shinji; Chiba, Satoshi

    2010-11-01

    Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.

  11. Dugesia sicula (Platyhelminthes, Tricladida): the colonizing success of an asexual Planarian

    PubMed Central

    2013-01-01

    Background Dugesia sicula is the only species of its genus not presenting an endemic or restricted distribution within the Mediterranean area. It mostly comprises fissiparous populations (asexual reproduction by body division and regeneration), most likely sexually sterile, and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion. However, its fissiparous reproduction can result in an apparent lack of diversity within the species, since genetic variation within individuals can be as large as between them because most individuals within a population are clones. We have estimated haplotype and nucleotide diversity of cytochrome oxidase I within and among individuals along the species distribution of a broad sample of D. sicula, including asexual and the two only sexual populations known today; and predicted its potential distribution based on climatic variables. Our aim was to determine the centre of colonisation origin, whether the populations are recent, and whether the species is expanding. Results The species presents 3 most frequent haplotypes, differing in a maximum of 11 base pairs. As expected from their fissiparous mode of reproduction, in half of all the analysed localities many individuals have multiple heteroplasmic haplotypes. The distribution of haplotypes is not geographically structured; however, the distribution of haplotypes and heteroplasmic populations shows higher diversity in the central Mediterranean region. The potential distribution predicted by climatic variables based modelling shows a preference for coastal areas and fits well with the observed data. Conclusions The distribution and frequency of the most frequent haplotypes and the presence of heteroplasmic individuals allow us to gain an understanding of the recent history of the species, together with previous knowledge on its phylogenetic relationships and age: The species most probably originated in Africa and dispersed through the central Mediterranean. After one or multiple populations became triploid and fissiparous, the species colonized the Mediterranean basin, likely both by its own means and helped by human activities. Its present distribution practically fulfils its potential distribution as modelled with climatic variables. Its prevalence in coastal regions with higher water temperatures predicts a likely future expansion to northern and more interior areas following the increase in temperatures due to climate change. PMID:24330464

  12. Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Solà, Eduard; Sluys, Ronald; Gritzalis, Konstantinos; Riutort, Marta

    2013-03-01

    In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2Mya ago, when the current Mediterranean

  13. Planarians.

    ERIC Educational Resources Information Center

    Hummer, Paul J.

    1991-01-01

    Describes the easy collection procedures and classroom uses of live planarians. Suggests that the use of live animals in the classroom will allow students to observe different biological processes exhibited by living organisms. (ZWH)

  14. First report of the exotic blue land planarian, Caenoplana coerulea (Platyhelminthes, Geoplanidae), on Menorca (Balearic Islands, Spain)

    PubMed Central

    Breugelmans, Karin; Cardona, Josep Quintana; Artois, Tom; Jordaens, Kurt; Backeljau, Thierry

    2012-01-01

    Abstract In April 2009 two specimens of a terrestrial flatworm were collected from under a rock in an orchard at Ciutadella de Menorca on the easternmost Balearic island of Menorca (Spain). Their external morphology suggested that both specimens belonged to the invasive blue planarian Caenoplana coerulea, a species which is native to eastern Australia. Sequence data of a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) and of the entire 18S ribosomal RNA confirm its identification. This is one of the first records of the species in Europe where it has only been found in one locality in the United Kingdom, France and NE Spain. PMID:22711997

  15. The invasive land planarian Platydemus manokwari (Platyhelminthes, Geoplanidae): records from six new localities, including the first in the USA.

    PubMed

    Justine, Jean-Lou; Winsor, Leigh; Barrière, Patrick; Fanai, Crispus; Gey, Delphine; Han, Andrew Wee Kien; La Quay-Velázquez, Giomara; Lee, Benjamin Paul Yi-Hann; Lefevre, Jean-Marc; Meyer, Jean-Yves; Philippart, David; Robinson, David G; Thévenot, Jessica; Tsatsia, Francis

    2015-01-01

    The land planarian Platydemus manokwari de Beauchamp, 1963 or "New Guinea flatworm" is a highly invasive species, mainly in the Pacific area, and recently in Europe (France). We report specimens from six additional countries and territories: New Caledonia (including mainland and two of the Loyalty Islands, Lifou and Maré), Wallis and Futuna Islands, Singapore, Solomon Islands, Puerto Rico, and Florida, USA. We analysed the COI gene (barcoding) in these specimens with two sets of primers and obtained 909 bp long sequences. In addition, specimens collected in Townsville (Australia) were also sequenced. Two haplotypes of the COI sequence, differing by 3.7%, were detected: the "World haplotype" found in France, New Caledonia, French Polynesia, Singapore, Florida and Puerto Rico; and the "Australian haplotype" found in Australia. The only locality with both haplotypes was in the Solomon Islands. The country of origin of Platydemus manokwari is New Guinea, and Australia and the Solomon Islands are the countries closest to New Guinea from which we had specimens. These results suggest that two haplotypes exist in the area of origin of the species, but that only one of the two haplotypes (the "World haplotype") has, through human agency, been widely dispersed. However, since P. manokwari is now recorded from 22 countries in the world and we have genetic information from only 8 of these, with none from New Guinea, this analysis provides only partial knowledge of the genetic structure of the invasive species. Morphological analysis of specimens from both haplotypes has shown some differences in ratio of the genital structures but did not allow us to interpret the haplotypes as different species. The new reports from Florida and Puerto Rico are firsts for the USA, for the American continent, and the Caribbean. P. manokwari is a known threat for endemic terrestrial molluscs and its presence is a matter of concern. While most of the infected territories reported until now were

  16. The invasive land planarian Platydemus manokwari (Platyhelminthes, Geoplanidae): records from six new localities, including the first in the USA

    PubMed Central

    Winsor, Leigh; Barrière, Patrick; Fanai, Crispus; Gey, Delphine; Han, Andrew Wee Kien; La Quay-Velázquez, Giomara; Lee, Benjamin Paul Yi-Hann; Lefevre, Jean-Marc; Meyer, Jean-Yves; Philippart, David; Robinson, David G.; Thévenot, Jessica; Tsatsia, Francis

    2015-01-01

    The land planarian Platydemus manokwari de Beauchamp, 1963 or “New Guinea flatworm” is a highly invasive species, mainly in the Pacific area, and recently in Europe (France). We report specimens from six additional countries and territories: New Caledonia (including mainland and two of the Loyalty Islands, Lifou and Maré), Wallis and Futuna Islands, Singapore, Solomon Islands, Puerto Rico, and Florida, USA. We analysed the COI gene (barcoding) in these specimens with two sets of primers and obtained 909 bp long sequences. In addition, specimens collected in Townsville (Australia) were also sequenced. Two haplotypes of the COI sequence, differing by 3.7%, were detected: the “World haplotype” found in France, New Caledonia, French Polynesia, Singapore, Florida and Puerto Rico; and the “Australian haplotype” found in Australia. The only locality with both haplotypes was in the Solomon Islands. The country of origin of Platydemus manokwari is New Guinea, and Australia and the Solomon Islands are the countries closest to New Guinea from which we had specimens. These results suggest that two haplotypes exist in the area of origin of the species, but that only one of the two haplotypes (the “World haplotype”) has, through human agency, been widely dispersed. However, since P. manokwari is now recorded from 22 countries in the world and we have genetic information from only 8 of these, with none from New Guinea, this analysis provides only partial knowledge of the genetic structure of the invasive species. Morphological analysis of specimens from both haplotypes has shown some differences in ratio of the genital structures but did not allow us to interpret the haplotypes as different species. The new reports from Florida and Puerto Rico are firsts for the USA, for the American continent, and the Caribbean. P. manokwari is a known threat for endemic terrestrial molluscs and its presence is a matter of concern. While most of the infected territories reported

  17. [Regeneration of planarians: experimental object].

    PubMed

    Sheĭman, I M; Kreshchenko, I D

    2015-01-01

    We discuss the expediency of using invertebrates, such as flatworms and planarians, as experimental objects. Free-living planarian flatworms (phylum Platyhelminthes, class Turbellaria) are invertebrate animals in which a bilateral symmetry appears for the first time in evolution and organs and tissues form. As the highest ecological link of the food chain--predators--these animals are characterized by a set of behavioral reactions controlled by a differentiated central nervous system. Planarians have unsurpassed ability to regenerate lost or damaged body parts. Owing to the ease of their breeding and their convenience for manipulations, these animals are used to study the influence of chemical and physical factors on the processes of life, growth, and reproduction. Currently, planarians are recognized as a model for biological research in the field of regeneration, stem cell biology, study of their proliferation and differentiation, as well as the regulatory mechanisms of morphogenetic processes. The genome of the planarian Schmidtea mediterranea was fully sequenced, which opened up the opportunity to work with this object at the molecular biological level. Furthermore, planarians are used in neurobiological and toxicological studies, in studying the evolutionary aspects of centralization of the nervous system, mechanisms of muscle contraction, and in the development of new antiparasitic drugs. This review aims to demonstrate the relevance and diversity of research conducted on simple biological objects--planarians--to awider audience to show the historical continuity of these studies and their wide geographical distribution and to focus on the studies carried out in Russia, which, as a rule, are not included in the foreign reviews on planarian regeneration. PMID:25898529

  18. Planarians Sense Simulated Microgravity and Hypergravity

    PubMed Central

    Adell, Teresa; Saló, Emili; van Loon, Jack J. W. A.

    2014-01-01

    Planarians are flatworms, which belong to the phylum Platyhelminthes. They have been a classical subject of study due to their amazing regenerative ability, which relies on the existence of adult totipotent stem cells. Nowadays they are an emerging model system in the field of developmental, regenerative, and stem cell biology. In this study we analyze the effect of a simulated microgravity and a hypergravity environment during the process of planarian regeneration and embryogenesis. We demonstrate that simulated microgravity by means of the random positioning machine (RPM) set at a speed of 60 °/s but not at 10 °/s produces the dead of planarians. Under hypergravity of 3 g and 4 g in a large diameter centrifuge (LDC) planarians can regenerate missing tissues, although a decrease in the proliferation rate is observed. Under 8 g hypergravity small planarian fragments are not able to regenerate. Moreover, we found an effect of gravity alterations in the rate of planarian scission, which is its asexual mode of reproduction. No apparent effects of altered gravity were found during the embryonic development. PMID:25309918

  19. Neurobehavioral toxicity of cadmium sulfate to the planarian Dugesia dorotocephala

    SciTech Connect

    Grebe, E.; Schaeffer, D.J. )

    1991-05-01

    The authors are developing bioassays which use planarians (free-living platyhelminthes) for the rapid determination of various types of toxicity, including acute mortality, tumorigenicity, and short-term neurobehavioral responses. Their motivation for using these animals is due to their importance as components of the aquatic ecology of unpolluted streams their sensitivity to low concentrations of environmental toxicants and the presence of a sensitive neurological system with a true brain which allows for complex social behavior. A previous paper described the results of a neurobehavioral bioassay using phenol in a crossover study. This paper reports a similar crossover study using cadmium sulfate.

  20. Spliced-leader trans-splicing in freshwater planarians.

    PubMed

    Zayas, Ricardo M; Bold, Tyler D; Newmark, Phillip A

    2005-10-01

    trans-Splicing, in which a spliced-leader (SL) RNA is appended to the most 5' exon of independently transcribed pre-mRNAs, has been described in a wide range of eukaryotes, from protozoans to chordates. Here we describe trans-splicing in the freshwater planarian Schmidtea mediterranea, a free-living member of the phylum Platyhelminthes. Analysis of an expressed sequence tag (EST) collection from this organism showed that over 300 transcripts shared one of two approximately 35-base sequences (Smed SL-1 and SL-2) at their 5' ends. Examination of genomic sequences encoding representatives of these transcripts revealed that these shared sequences were transcribed elsewhere in the genome. RNA blot analysis, 5' and 3' rapid amplification of cDNA ends, as well as genomic sequence data showed that 42-nt SL sequences were derived from small RNAs of approximately 110 nt. Similar sequences were also found at the 5' ends of ESTs from the planarian Dugesia japonica. trans-Splicing has already been described in numerous representatives of the phylum Platyhelminthes (trematodes, cestodes, and polyclads); its presence in two representatives of the triclads supports the hypothesis that this mode of RNA processing is ancestral within this group. The upcoming complete genome sequence of S. mediterranea, combined with this animal's experimental accessibility and susceptibility to RNAi, provide another model organism in which to study the function of the still-enigmatic trans-splicing. PMID:15972844

  1. Two new species of freshwater flatworms (Platyhelminthes: Tricladida: Continenticola) from South American caves.

    PubMed

    Souza, Stella; Morais, Ana Laura; Bichuette, Maria Elina; Leal-Zanchet, Ana

    2016-01-01

    The diversity of freshwater triclads in the Neotropical region is considered to be low, but extensive areas of South America remain almost unexplored. Herein we describe two cave-dwelling, new species of Girardia, one from a transition zone of the Cerrado and Caatinga phytophysiognomies and the other from the Cerrado phytophysiognomy. The species from the Cerrado-Caatinga transition is a troglobite, eyeless and whitish; the species from the Cerrado area is possibly a troglophile, since it shows heavily pigmented body and eyes. Each species is easily recognized by a unique combination of features in its external morphology and copulatory apparatus. The two new species of Girardia show a restricted distribution, even the troglophile, and occur in caves without legal protection. Therefore, they must be considered as vulnerable organisms in a conservation context. PMID:27394369

  2. Histological and histochemical aspects of the penial glands of Girardia biapertura Sluys, 1997 (Platyhelminthes, Tricladida, Paludicola).

    PubMed

    Souza, S T; Leal-Zanchet, A M

    2002-08-01

    Girardia biapertura was described with sperm ducts penetrating the penis bulb, subsequently opening separately at the tip of the penis papilla and receiving the abundant secretion of penial glands. In the present work, the penial glands of this species have been histologically and histochemically analysed, and four types of secretory cells are distinguished. The openings of the penial glands into the intrabulbar and intrapapillar sperm ducts, designated here as intrapenial ducts, allow for the distinction between three histologically differentiated regions. The most proximal region possibly corresponds to the bulbar cavity of other freshwater triclads whereas the median and distal portions correspond to the ejaculatory duct. The proximal region of the intrapenial ducts receives mainly the openings of a secretory cell type (type I) that produces a proteinaceous secretion. A second type of secretory cell (type II) that secretes neutral mucopolyssacharides opens into the median region of the intrapenial ducts. The distal portion of the ducts receives two types of secretory cells (types III and IV) which secret glycoprotein and glycosaminoglycans, respectively. Types III and IV open also directly into the male atrium through the epithelium of the penis papilla. A comparison with the results presented here and those of other authors for species of Girardia is provided and the importance of the study of the penial glands for taxonomic characterisation of freshwater triclads is emphasised. PMID:12530192

  3. A quantitative metabolomics peek into planarian regeneration.

    PubMed

    Natarajan, Nivedita; Ramakrishnan, Padma; Lakshmanan, Vairavan; Palakodeti, Dasaradhi; Rangiah, Kannan

    2015-05-21

    The fresh water planarian species Schmidtea mediterranea is an emerging stem cell model because of its capability to regenerate a whole animal from a small piece of tissue. It is one of the best model systems to address the basic mechanisms essential for regeneration. Here, we are interested in studying the roles of various amines, thiols and nucleotides in planarian regeneration, stem cell function and growth. We developed mass spectrometry based quantitative methods and validated the differential enrichment of 35 amines, 7 thiol metabolites and 4 nucleotides from both intact and regenerating planarians. Among the amines, alanine in sexual and asparagine in asexual are the highest (>1000 ng/mg) in the intact planarians. The levels of thiols such as cysteine and GSH are 651 and 1107 ng mg(-1) in planarians. Among the nucleotides, the level of cGMP is the lowest (0.03 ng mg(-1)) and the level of AMP is the highest (187 ng mg(-1)) in both of the planarian strains. We also noticed increasing levels of amines in both anterior and posterior regenerating planarians. The blastema from day 3 regenerating planarians also showed higher amounts of many amines. Interestingly, the thiol (cysteine and GSH) levels are well maintained during planarian regeneration. This suggests an inherent and effective mechanism to control induced oxidative stress because of the robust regeneration and stem cell proliferation. Like in intact planarians, the level of cGMP is also very low in regenerating planarians. Surprisingly, the levels of amines and thiols in head regenerating blastemas are ∼3 times higher compared to those for tail regenerating blastemas. Thus our results strongly indicate the potential roles of amines, thiols and nucleotides in planarian regeneration. PMID:25815385

  4. Comparative Analysis of Cystatin Superfamily in Platyhelminths

    PubMed Central

    Guo, Aijiang

    2015-01-01

    The cystatin superfamily is comprised of cysteine proteinase inhibitors and encompasses at least 3 subfamilies: stefins, cystatins and kininogens. In this study, the platyhelminth cystatin superfamily was identified and grouped into stefin and cystatin subfamilies. The conserved domain of stefins (G, QxVxG) was observed in all members of platyhelminth stefins. The three characteristics of cystatins, the cystatin-like domain (G, QxVxG, PW), a signal peptide, and one or two conserved disulfide bonds, were observed in platyhelminths, with the exception of cestodes, which lacked the conserved disulfide bond. However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported. Tertiary structure analysis of Taenia solium cystatin, one of the cestode cystatins, demonstrated that the N-terminus of T. solium cystatin formed a five turn α-helix, a five stranded β-pleated sheet and a hydrophobic edge, similar to the structure of chicken cystatin. Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin. However, the two models were not similar regarding the location of the second disulfide bridge of chicken cystatin. These results showed that T. solium cystatin and chicken cystatin had similarities and differences, suggesting that the biochemistry of T. solium cystatin could be similar to chicken cystatin in its inhibitory function and that it may have further functional roles. The same results were obtained for other cestode cystatins. Phylogenetic analysis showed that cestode cystatins constituted an independent clade and implied that cestode cystatins should be considered to have formed a new clade during evolution. PMID:25853513

  5. Dynamics of asexual reproduction in planarians

    NASA Astrophysics Data System (ADS)

    Schoetz, Eva-Maria; Lincoln, Bryan; Quinodoz, Sofia

    2011-03-01

    Planaria research is experiencing a resurgence due to the development of molecular tools, the Planarian genome project and database resources. Despite the resulting progress in planarian biology research, an extensive study of their physical properties remains to be undertaken. We developed a method to collect a large amount of data on the dynamics of clonal reproduction in the freshwater planarian S.mediterranea. The capability of planarians to regenerate an entire organism from a minuscule body part is based on a homogeneously distributed stem cell population that comprises 25-30% of all cells. Due to this stem cell contingent, planarians can reproduce spontaneously by dividing into a larger head and a smaller tail piece, which then will rebuild the missing body parts, including a central nervous system, within about a week. Time-lapse imaging allows us to characterize the fission process in detail, revealing the stages of the process as well as capturing the nature of the rupture itself. A traction force measurement setup is being developed to allow us to quantify the forces planarians exert on the substrate during reproduction, a macroscopic analog to the Traction Force Microscopy setups used to determine local cellular forces. We are particularly interested in the molecular processes during division and the interplay between tissue mechanics and cell signaling.

  6. Nociception and escape behavior in planarians

    NASA Astrophysics Data System (ADS)

    Schoetz Collins, Eva-Maria

    2015-03-01

    Planarians are famous and widely studied for their regenerative capabilities. When a moving planarian is cut through the middle, the resulting head and tail pieces instantaneously retract and exhibit a characteristic escape response that differs from normal locomotion. In asexual animals, a similar reaction is observed when the planarian undergoes fission, suggesting that reproduction through self-tearing is a rather traumatic event for the animal. Using a multiscale approach, we unravel the dynamics, mechanics, and functional aspects of the planarian escape response. This musculature-driven gait was found to be a dominating response that supersedes the urge to feed or reproduce and quantitatively differs from other modes of planarian locomotion (gliding, peristalsis). We show that this escape gait constitutes the animal's pain response mediated by TRP like receptors and the neurotransmitter histamine, and that it can be induced through adverse thermal, mechanical, electrical or chemical stimuli. Ultimately, we will examine the neuronal subpopulations involved in mediating escape reflexes in planarians and how they are functionally restored during regeneration, thereby gaining mechanistic insight into the neuronal circuits required for specific behaviors. Supported by BWF CASI and Sloan Foundation.

  7. [Own Chemiluminescence of Planarian Neoblasts during Regeneration].

    PubMed

    Tiras, H P; Gudkov, S V; Emelyanenko, V I; Aslanidi, K B

    2015-01-01

    We investigated the kinetics of the luminescence induced by reactive oxygen species in planarians during regeneration process. It was found that regeneration is accompanied with changes in the concentration of reactive oxygen species correlating with energy-intensive processes such as oxidative stress, caused by damage to cell membranes in the dissection of the planarian, phagocytosis of dying cells and mitosis of neoblasts. We showed for the first time that there is an opportunity of registering the physiological state of pluripotent stem cells at the level of the organism in vivo. PMID:26591608

  8. Scrunching: a novel escape gait in planarians

    NASA Astrophysics Data System (ADS)

    Cochet-Escartin, Olivier; Mickolajczyk, Keith J.; Collins, Eva-Maria S.

    2015-10-01

    The ability to escape a predator or other life-threatening situations is central to animal survival. Different species have evolved unique strategies under anatomical and environmental constraints. In this study, we describe a novel musculature-driven escape gait in planarians, ‘scrunching’, which is quantitatively different from other planarian gaits, such as gliding and peristalsis. We show that scrunching is a conserved gait among different flatworm species, underlying its importance as an escape mechanism. We further demonstrate that it can be induced by a variety of physical stimuli, including amputation, high temperature, electric shock and low pH. We discuss the functional basis for scrunching as the preferential gait when gliding is impaired due to a disruption of mucus production. Finally, we show that the key mechanical features of scrunching are adequately captured by a simple biomechanical model that is solely based on experimental data from traction force microscopy and tissue rheology without fit parameters. Together, our results form a complete description of this novel form of planarian locomotion. Because scrunching has distinct dynamics, this gait can serve as a robust behavioral readout for studies of motor neuron and muscular functions in planarians and in particular the restoration of these functions during regeneration.

  9. Scrunching: a novel escape gait in planarians.

    PubMed

    Cochet-Escartin, Olivier; Mickolajczyk, Keith J; Collins, Eva-Maria S

    2015-10-01

    The ability to escape a predator or other life-threatening situations is central to animal survival. Different species have evolved unique strategies under anatomical and environmental constraints. In this study, we describe a novel musculature-driven escape gait in planarians, 'scrunching', which is quantitatively different from other planarian gaits, such as gliding and peristalsis. We show that scrunching is a conserved gait among different flatworm species, underlying its importance as an escape mechanism. We further demonstrate that it can be induced by a variety of physical stimuli, including amputation, high temperature, electric shock and low pH. We discuss the functional basis for scrunching as the preferential gait when gliding is impaired due to a disruption of mucus production. Finally, we show that the key mechanical features of scrunching are adequately captured by a simple biomechanical model that is solely based on experimental data from traction force microscopy and tissue rheology without fit parameters. Together, our results form a complete description of this novel form of planarian locomotion. Because scrunching has distinct dynamics, this gait can serve as a robust behavioral readout for studies of motor neuron and muscular functions in planarians and in particular the restoration of these functions during regeneration. PMID:26356147

  10. Muscle Cells Provide Instructions for Planarian Regeneration

    PubMed Central

    Witchley, Jessica N.; Mayer, Mirjam; Wagner, Daniel E.; Owen, Jared H.; Reddien, Peter W.

    2014-01-01

    Regeneration requires both potential and instructions for tissue replacement. In planarians, pluripotent stem cells have the potential to produce all new tissue. The identities of the cells that provide regeneration instructions are unknown. Here, we report that position control genes (PCGs) that control regeneration and tissue turnover are expressed in a subepidermal layer of nonneoblast cells. These subepidermal cells coexpress many PCGs. We propose that these subepidermal cells provide a system of body coordinates and positional information for regeneration, and identify them to be muscle cells of the planarian body wall. Almost all planarian muscle cells express PCGs, suggesting a dual function: contraction and control of patterning. PCG expression is dynamic in muscle cells after injury, even in the absence of neoblasts, suggesting that muscle is instructive for regeneration. We conclude that planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of any body region. PMID:23954785

  11. Planarian brain regeneration as a model system for developmental neurotoxicology

    PubMed Central

    Hagstrom, Danielle; Cochet‐Escartin, Olivier

    2016-01-01

    Abstract Freshwater planarians, famous for their regenerative prowess, have long been recognized as a valuable in vivo animal model to study the effects of chemical exposure. In this review, we summarize the current techniques and tools used in the literature to assess toxicity in the planarian system. We focus on the planarian's particular amenability for neurotoxicology and neuroregeneration studies, owing to the planarian's unique ability to regenerate a centralized nervous system. Zooming in from the organismal to the molecular level, we show that planarians offer a repertoire of morphological and behavioral readouts while also being amenable to mechanistic studies of compound toxicity. Finally, we discuss the open challenges and opportunities for planarian brain regeneration to become an important model system for modern toxicology. PMID:27499880

  12. Germline Defects Caused by Smed-boule RNA-Interference Reveal That Egg Capsule Deposition Occurs Independently of Fertilization, Ovulation, Mating, or the Presence of Gametes in Planarian Flatworms

    PubMed Central

    Steiner, Jessica Kathryne; Tasaki, Junichi; Rouhana, Labib

    2016-01-01

    Few animals are known to lay eggs in the absence of ovulation or copulation, as it is presumably energetically wasteful and subjected to negative selection. Characterization of Smed-boule, a member of the DAZ family of germline RNA-binding proteins, revealed that egg capsule (or capsule) production and deposition occurs independently of the presence of gametes in the planarian flatworm Schmidtea mediterranea. Reduction of Smed-boule expression by RNA-interference (RNAi) causes ablation of spermatogonial stem cells and the inability of ovarian germline stem cells to undergo oogenesis. Although animals subjected to Smed-boule RNAi lose their gametes and become sterile, they continue to lay egg capsules. Production of sterile capsules is even observed in virgin Smed-boule(RNAi) and control planarians maintained in complete isolation, demonstrating that egg production in S. mediterranea occurs independently of ovulation, fertilization, or mating. Evidence suggests that this is a conserved feature amongst Platyhelminthes, and therefore relevant to the pathology and dissemination of parasitic flatworms. These findings demonstrate that Smed-boule functions at different stages during male and female germline stem cell development, and also demonstrate that egg capsule production by planarian flatworms occurs independently of signals produced by mating or ova. PMID:27149082

  13. Germline Defects Caused by Smed-boule RNA-Interference Reveal That Egg Capsule Deposition Occurs Independently of Fertilization, Ovulation, Mating, or the Presence of Gametes in Planarian Flatworms.

    PubMed

    Steiner, Jessica Kathryne; Tasaki, Junichi; Rouhana, Labib

    2016-05-01

    Few animals are known to lay eggs in the absence of ovulation or copulation, as it is presumably energetically wasteful and subjected to negative selection. Characterization of Smed-boule, a member of the DAZ family of germline RNA-binding proteins, revealed that egg capsule (or capsule) production and deposition occurs independently of the presence of gametes in the planarian flatworm Schmidtea mediterranea. Reduction of Smed-boule expression by RNA-interference (RNAi) causes ablation of spermatogonial stem cells and the inability of ovarian germline stem cells to undergo oogenesis. Although animals subjected to Smed-boule RNAi lose their gametes and become sterile, they continue to lay egg capsules. Production of sterile capsules is even observed in virgin Smed-boule(RNAi) and control planarians maintained in complete isolation, demonstrating that egg production in S. mediterranea occurs independently of ovulation, fertilization, or mating. Evidence suggests that this is a conserved feature amongst Platyhelminthes, and therefore relevant to the pathology and dissemination of parasitic flatworms. These findings demonstrate that Smed-boule functions at different stages during male and female germline stem cell development, and also demonstrate that egg capsule production by planarian flatworms occurs independently of signals produced by mating or ova. PMID:27149082

  14. Planarian Immobilization, Partial Irradiation, and Tissue Transplantation

    PubMed Central

    Guedelhoefer IV, Otto C.; Sánchez Alvarado, Alejandro

    2012-01-01

    The planarian, a freshwater flatworm, has proven to be a powerful system for dissecting metazoan regeneration and stem cell biology1,2. Planarian regeneration of any missing or damaged tissues is made possible by adult stem cells termed neoblasts3. Although these stem cells have been definitively shown to be pluripotent and singularly capable of reconstituting an entire animal4, the heterogeneity within the stem cell population and the dynamics of their cellular behaviors remain largely unresolved. Due to the large number and wide distribution of stem cells throughout the planarian body plan, advanced methods for manipulating subpopulations of stem cells for molecular and functional study in vivo are needed. Tissue transplantation and partial irradiation are two methods by which a subpopulation of planarian stem cells can be isolated for further study. Each technique has distinct advantages. Tissue transplantation allows for the introduction of stem cells, into a naïve host, that are either inherently genetically distinct or have been previously treated pharmacologically. Alternatively, partial irradiation allows for the isolation of stem cells within a host, juxtaposed to tissue devoid of stem cells, without the introduction of a wound or any breech in tissue integrity. Using these two methods, one can investigate the cell autonomous and non-autonomous factors that control stem cell functions, such as proliferation, differentiation, and migration. Both tissue transplantation5,6 and partial irradiation7 have been used historically in defining many of the questions about planarian regeneration that remain under study today. However, these techniques have remained underused due to the laborious and inconsistent nature of previous methods. The protocols presented here represent a large step forward in decreasing the time and effort necessary to reproducibly generate large numbers of grafted or partially irradiated animals with efficacies approaching 100 percent. We

  15. Planarian Phototactic Assay Reveals Differential Behavioral Responses Based on Wavelength

    PubMed Central

    Paskin, Taylor R.; Jellies, John; Bacher, Jessica; Beane, Wendy S.

    2014-01-01

    Planarians are free-living aquatic flatworms that possess a well-documented photophobic response to light. With a true central nervous system and simple cerebral eyes (ocelli), planarians are an emerging model for regenerative eye research. However, comparatively little is known about the physiology of their photoreception or how their behavior is affected by various wavelengths. Most phototactic studies have examined planarian behavior using white light. Here, we describe a novel planarian behavioral assay to test responses to small ranges of visible wavelengths (red, blue, green), as well as ultraviolet (UV) and infrared (IR) which have not previously been examined. Our data show that planarians display behavioral responses across a range of wavelengths. These responses occur in a hierarchy, with the shortest wavelengths (UV) causing the most intense photophobic responses while longer wavelengths produce no effect (red) or an apparent attraction (IR). In addition, our data reveals that planarian photophobia is comprised of both a general photophobic response (that drives planarians to escape the light source regardless of wavelength) and wavelength-specific responses that encompass specific behavioral reactions to individual wavelengths. Our results serve to improve the understanding of planarian phototaxis and suggest that behavioral studies performed with white light mask a complex behavioral interaction with the environment. PMID:25493551

  16. Collecting Planarians: A Good Choice for a Field Trip.

    ERIC Educational Resources Information Center

    Cha, Heeyoung

    2001-01-01

    Describes a field trip to collect planarians as successful in generating interest in the sciences. This activity is suitable for all grade levels as a field trip or biology lab. Planarians can be easily collected from streams across the United States. Once in the classroom, planaria are easily fed and cared for. (SAH)

  17. On-chip immobilization of planarians for in vivo imaging

    PubMed Central

    Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

    2014-01-01

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

  18. Identification of planarian homeobox sequences indicates the antiquity of most Hox/homeotic gene subclasses.

    PubMed Central

    Balavoine, G; Telford, M J

    1995-01-01

    The homeotic gene complex (HOM-C) is a cluster of genes involved in the anteroposterior axial patterning of animal embryos. It is composed of homeobox genes belonging to the Hox/HOM superclass. Originally discovered in Drosophila, Hox/HOM genes have been identified in organisms as distantly related as arthropods, vertebrates, nematodes, and cnidarians. Data obtained in parallel from the organization of the complex, the domains of gene expression during embryogenesis, and phylogenetic relationships allow the subdivision of the Hox/HOM superclass into five classes (lab, pb/Hox3, Dfd, Antp, and Abd-B) that appeared early during metazoan evolution. We describe a search for homologues of these genes in platyhelminths, triploblast metazoans emerging as an outgroup to the great coelomate ensemble. A degenerate PCR screening for Hox/HOM homeoboxes in three species of triclad planarians has revealed 10 types of Antennapedia-like genes. The homeobox-containing sequences of these PCR fragments allowed the amplification of the homeobox-coding exons for five of these genes in the species Polycelis nigra. A phylogenetic analysis shows that two genes are clear orthologues of Drosophila labial, four others are members of a Dfd/Antp superclass, and a seventh gene, although more difficult to classify with certainty, may be related to the pb/Hox3 class. Together with previously identified Hox/HOM genes in other flatworms, our analyses demonstrate the existence of an elaborate family of Hox/HOM genes in the ancestor of all triploblast animals. Images Fig. 4 PMID:7638172

  19. Berberine exposure triggers developmental effects on planarian regeneration

    PubMed Central

    Balestrini, Linda; Isolani, Maria Emilia; Pietra, Daniele; Borghini, Alice; Bianucci, Anna Maria; Deri, Paolo; Batistoni, Renata

    2014-01-01

    The mechanisms of action underlying the pharmacological properties of the natural alkaloid berberine still need investigation. Planarian regeneration is instrumental in deciphering developmental responses following drug exposure. Here we report the effects of berberine on regeneration in the planarian Dugesia japonica. Our findings demonstrate that this compound perturbs the regenerative pattern. By real-time PCR screening for the effects of berberine exposure on gene expression, we identified alterations in the transcriptional profile of genes representative of different tissues, as well as of genes involved in extracellular matrix (ECM) remodeling. Although berberine does not influence cell proliferation/apoptosis, our experiments prove that this compound causes abnormal regeneration of the planarian visual system. Potential berberine-induced cytotoxic effects were noticed in the intestine. Although we were unable to detect abnormalities in other structures, our findings, sustained by RNAi-based investigations, support the possibility that berberine effects are critically linked to anomalous ECM remodeling in treated planarians. PMID:24810466

  20. The Retinoblastoma pathway regulates stem cell proliferation in freshwater planarians.

    PubMed

    Zhu, Shu Jun; Pearson, Bret J

    2013-01-15

    Freshwater planarians are flatworms of the Lophotrochozoan superphylum and are well known for their regenerative abilities, which rely on a large population of pluripotent adult stem cells. However, the mechanisms by which planarians maintain a precise population of adult stem cells while balancing proliferation and cell death, remain to be elucidated. Here we have identified, characterized, and functionally tested the core Retinoblastoma (Rb) pathway components in planarian adult stem cell biology. The Rb pathway is an ancient and conserved mechanism of proliferation control from plants to animals and is composed of three core components: an Rb protein, and a transcription factor heterodimer of E2F and DP proteins. Although the planarian genome contains all components of the Rb pathway, we found that they have undergone gene loss from the ancestral state, similar to other species in their phylum. The single Rb homolog (Smed-Rb) was highly expressed in planarian stem cells and was required for stem cell maintenance, similar to the Rb-homologs p107 and p130 in vertebrates. We show that planarians and their phylum have undergone the most severe reduction in E2F genes observed thus far, and the single remaining E2F was predicted to be a repressive-type E2F (Smed-E2F4-1). Knockdown of either Smed-E2F4-1 or its dimerization partner Dp (Smed-Dp) by RNAi resulted in temporary hyper-proliferation. Finally, we showed that known Rb-interacting genes in other systems, histone deacetylase 1 and cyclinD (Smed-HDAC1; Smed-cycD), were similar to Rb in expression and phenotypes when knocked down by RNAi, suggesting that these established interactions with Rb may also be conserved in planarians. Together, these results showed that planarians use the conserved components of the Rb tumor suppressor pathway to control proliferation and cell survival. PMID:23123964

  1. Bioaccumulation and toxicodynamics of cadmium to freshwater planarian and the protective effect of N-acetylcysteine.

    PubMed

    Wu, Jui-Pin; Chen, Hon-Cheng; Li, Mei-Hui

    2012-08-01

    Although toxic responses of freshwater planarians after exposure to environmental toxicants can be observed through external toxicological end points, physiological responses inside the bodies of treated planarians have rarely been investigated. The present study was designed, using cadmium (Cd) as a reference toxicant, to determine its bioaccumulation and toxicodynamics in the freshwater planarian, Dugesia japonica, after acute toxicity was obtained. Accumulated Cd concentrations, metallothionein levels, and the oxidative status in planarians were determined after exposure to Cd. Furthermore, we hypothesized that the acute death of Cd-treated planarians was associated with increased oxidative stress. After Cd-treated planarians were coexposed to antioxidant, N-acetylcysteine (NAC), we found that NAC protected planarians from Cd lethality by maintaining the oxidative status and decreasing the bioaccumulation of Cd. The results of the present study support planarians being used as a practical model for toxicological studies of environmental contaminants in the future. PMID:22481525

  2. Slo1 regulates ethanol-induced scrunching in freshwater planarians.

    PubMed

    Cochet-Escartin, Olivier; Carter, Jason A; Chakraverti-Wuerthwein, Milena; Sinha, Joydeb; Collins, Eva-Maria S

    2016-01-01

    When freshwater planarians are exposed to a low-percentage (0.5%-1%) alcohol solution, they display a characteristic 'drunken' phenotype. Here we show that this drunken phenotype is a mixture of cilia-mediated gliding and scrunching, a muscular-based planarian gait which we recently demonstrated to be triggered by adverse environmental stimuli. At exogenous ethanol concentrations ≥2% (v/v), planarians become gradually immobilized and ultimately die. Using RNA interference (RNAi) for targeted gene knockdown, we elucidate the molecular basis for ethanol sensing and show that the big potassium ion channel SLO1 is necessary for ethanol sensitivity in planarians. Because slo1(RNAi) animals maintain their ability to scrunch in response to other adverse triggers, these results suggest that slo1 specifically regulates ethanol sensitivity and not the scrunching gait per se. Furthermore, this study demonstrates the ease of performing pharmacological studies in planarians. Combined with the worms' amenability to quantitative behavioral assays and targeted gene knockdown, planarians are a valuable model organism for studying the effect of neuroactive compounds on brain function and behavior. PMID:27609598

  3. GPCRs Direct Germline Development and Somatic Gonad Function in Planarians

    PubMed Central

    Saberi, Amir; Beets, Isabel; Schoofs, Liliane; Newmark, Phillip A.

    2016-01-01

    Planarians display remarkable plasticity in maintenance of their germline, with the ability to develop or dismantle reproductive tissues in response to systemic and environmental cues. Here, we investigated the role of G protein-coupled receptors (GPCRs) in this dynamic germline regulation. By genome-enabled receptor mining, we identified 566 putative planarian GPCRs and classified them into conserved and phylum-specific subfamilies. We performed a functional screen to identify NPYR-1 as the cognate receptor for NPY-8, a neuropeptide required for sexual maturation and germ cell differentiation. Similar to NPY-8, knockdown of this receptor results in loss of differentiated germ cells and sexual maturity. NPYR-1 is expressed in neuroendocrine cells of the central nervous system and can be activated specifically by NPY-8 in cell-based assays. Additionally, we screened the complement of GPCRs with expression enriched in sexually reproducing planarians, and identified an orphan chemoreceptor family member, ophis, that controls differentiation of germline stem cells (GSCs). ophis is expressed in somatic cells of male and female gonads, as well as in accessory reproductive tissues. We have previously shown that somatic gonadal cells are required for male GSC specification and maintenance in planarians. However, ophis is not essential for GSC specification or maintenance and, therefore, defines a secondary role for planarian gonadal niche cells in promoting GSC differentiation. Our studies uncover the complement of planarian GPCRs and reveal previously unappreciated roles for these receptors in systemic and local (i.e., niche) regulation of germ cell development. PMID:27163480

  4. Toxicity of tributyltin (TBT) to the freshwater planarian Schmidtea mediterranea.

    PubMed

    Ofoegbu, Pearl U; Simão, Fátima C P; Cruz, Andreia; Mendo, Sónia; Soares, Amadeu M V M; Pestana, João L T

    2016-04-01

    The freshwater planarian Schmidtea mediterranea, one of the best characterized animal models for regeneration research and developmental biology, is being recognised as a useful species for ecotoxicological studies. Sensitive endpoints related to planarians' behaviour and regeneration can be easily evaluated after exposure to environmental stressors. In this work the sensitivity of S. mediterranea to a gradient of environmentally relevant concentrations of TBT was studied using multiple endpoints like survival, locomotion, head regeneration and DNA damage. In addition, a feeding assay based on planarian's predatory behaviour was performed. Results indicated that TBT is toxic to planarians with LC50's of 1.87 μg L(-1) Sn and 1.31 μg L(-1) Sn at 48 h and 96 h of exposure respectively. Sub-lethal exposures to TBT significantly reduced locomotion and feeding, delayed head regeneration and caused DNA damage in planarians. The behavioural endpoints (feeding and locomotion) and head regeneration were the most sensitive parameters followed by DNA damage. Similar to other aquatic model organisms, S. mediterranea showed high sensitivity towards TBT exposure. Based on our results, and though further research is required concerning their sensitivity to other pollutants, the use of freshwater planarians as a model species in ecotoxicology is discussed. PMID:26802264

  5. GPCRs Direct Germline Development and Somatic Gonad Function in Planarians.

    PubMed

    Saberi, Amir; Jamal, Ayana; Beets, Isabel; Schoofs, Liliane; Newmark, Phillip A

    2016-05-01

    Planarians display remarkable plasticity in maintenance of their germline, with the ability to develop or dismantle reproductive tissues in response to systemic and environmental cues. Here, we investigated the role of G protein-coupled receptors (GPCRs) in this dynamic germline regulation. By genome-enabled receptor mining, we identified 566 putative planarian GPCRs and classified them into conserved and phylum-specific subfamilies. We performed a functional screen to identify NPYR-1 as the cognate receptor for NPY-8, a neuropeptide required for sexual maturation and germ cell differentiation. Similar to NPY-8, knockdown of this receptor results in loss of differentiated germ cells and sexual maturity. NPYR-1 is expressed in neuroendocrine cells of the central nervous system and can be activated specifically by NPY-8 in cell-based assays. Additionally, we screened the complement of GPCRs with expression enriched in sexually reproducing planarians, and identified an orphan chemoreceptor family member, ophis, that controls differentiation of germline stem cells (GSCs). ophis is expressed in somatic cells of male and female gonads, as well as in accessory reproductive tissues. We have previously shown that somatic gonadal cells are required for male GSC specification and maintenance in planarians. However, ophis is not essential for GSC specification or maintenance and, therefore, defines a secondary role for planarian gonadal niche cells in promoting GSC differentiation. Our studies uncover the complement of planarian GPCRs and reveal previously unappreciated roles for these receptors in systemic and local (i.e., niche) regulation of germ cell development. PMID:27163480

  6. Toxic effects of selenium and copper on the planarian, Dugesia dorotocephala

    SciTech Connect

    Rauscher, J.D.

    1988-01-01

    Aquatic toxicologists have become increasingly concerned with the effects of sublethal concentrations of toxicants on aquatic organisms. Sublethal effects of toxicants on freshwater invertebrates were reviewed. Selenium (Se) and copper (Cu) are both essential trace elements and toxicants. Se has been reported to alter the toxicity of heavy metals. Planarians, Dugesia dorotocephala, were used as test animals. The objectives of this study were to determine: (1) acute toxicity of Se on planarians and the effect of the number of planarians per test chamber, (2) interaction of the acute toxicity of Se and Cu on planarians, and (3) sublethal effects of Se and Cu on planarians.

  7. Mitochondrial genome data support the basal position of acoelomorpha and the polyphyly of the platyhelminthes

    SciTech Connect

    Ruiz-Trillo, Inaki; Riutort, Marta; Fourcade, H. Matthew; Baguna, Jaume; Boore, Jeffrey L.

    2004-05-01

    We determined 9.7, 5.2, and 6.8 kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels + nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum.

  8. Optical coherence tomography: A new strategy to image planarian regeneration

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Sheng; Chu, Chin-Chou; Lin, Jen-Jen; Chang, Chien-Cheng; Wang, Chun-Chieh; Wang, Chiao-Yin; Tsui, Po-Hsiang

    2014-09-01

    The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from -0.2 dB/μm to -0.05 dB/μm, between Day 1 and Day 6, and then increased to -0.2 dB/μm on Day 14. The intensity ratios decreased to approximately 0.8 on Day 6, and increased to between 0.8 and 0.9 on Day 14. The texture parameters of contrast, correlation, and homogeneity exhibited trends similar to the signal attenuation rates and intensity ratios during the planarian regeneration. The proposed OCT parameters might provide biological information regarding cell apoptosis and the formation of a mass of new cells during planarian regeneration. Therefore, OCT imaging is a potentially effective method for planarian studies.

  9. Planarian regeneration under micro- and hyper-gravity simulated contexts

    NASA Astrophysics Data System (ADS)

    Auletta, Gennaro; Van Loon, ing.. Jack J. W. A.; Adell, Teresa; Salo, Emili

    Planarians are non-parasitic flatworms of the Turbellaria class, some of which show the striking ability to regenerate any part of their body, even the head, in few days. Planarians are common to many parts of the world, living in both saltwater and freshwater, as well as in terrestrial areas. Due to their plasticity Planarians have been a classical model for the study of the mechanisms of regeneration. Currently, their cheap and easy maintenance, as well as the establishment of robust genetic tools, have converted them into an essential system in the field of stem cells and regenerative medicine. The aim of our project is to study the effect that micro- and hyper- gravity could exert during the process of planarians regeneration. The reason for planarians extreme regenerative capability is the maintenance until adulthood of a population of totipotent stem cells as well as the continuous activation of the cell-cell communication molecular pathways. Our prediction is that the alteration of the forces could affect planarians regeneration at different levels: 1) To regenerate, planarians must activate both proliferative and apoptotic responses, in order to create new tissue and to remodel the pre-existing one, respectively. Both cellular processes have been reported to be altered in several models under differential gravitational forces; 2) In planarians, the main intercellular signalling pathways (Wnt, TGFb, BMP, Hh, EGF) must control the process of differentiation and determination of each cell. For instances, it has been demonstrated that the differential activity of the wnt/beta-catenin pathway specifies the posterior (tail) versus the anterior (head) identity. Those pathways rely on the distance that secreted molecules (morphogens) are able to reach. Either this mechanism consist in a passive diffusion or an active transport through phyllopodia, it could sense the magnitude of the gravitational force; 3) The epidermis of planarians is covered by cilia, which beat

  10. Planarians: an In Vivo Model for Regenerative Medicine

    PubMed Central

    Karami, Ali; Tebyanian, Hamid; Goodarzi, Vahabodin; Shiri, Sajad

    2015-01-01

    The emergence of regenerative medicine has raised the hope of treating an extraordinary range of disease and serious injuries. Understanding the processes of cell proliferation, differentiation and pattern formation in regenerative organisms could help find ways to enhance the poor regenerative abilities shown by many other animals, including humans. Recently, planarians have emerged as an attractive model in which to study regeneration. These animals are considering as in vivo plate, during which we can study the behavior and characristics of stem cells in their own niche. A variety of characteristic such as: simplicity, easy to manipulate experimentally, the existence of more than 100 years of literature, makes these animals an extraordinary model for regenerative medicine researches. Among planarians free-living freshwater hermaphrodite Schmidtea mediterranea has emerged as a suitable model system because it displays robust regenerative properties and, unlike most other planarians, it is a stable diploid with a genome size of about 4.8×108 base pairs, nearly half that of other common planarians. Planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of anybody region. neoblasts represent roughly 25~30 percent of all planarian cells and are scattered broadly through the parenchyma, being absent only from the animal head tips and the pharynx. Two models for neo-blast specification have been proposed; the naive model posits that all neoblasts are stem cells with the same potential and are a largely homogeneous population. PMID:26634061

  11. Planarians: an In Vivo Model for Regenerative Medicine.

    PubMed

    Karami, Ali; Tebyanian, Hamid; Goodarzi, Vahabodin; Shiri, Sajad

    2015-11-01

    The emergence of regenerative medicine has raised the hope of treating an extraordinary range of disease and serious injuries. Understanding the processes of cell proliferation, differentiation and pattern formation in regenerative organisms could help find ways to enhance the poor regenerative abilities shown by many other animals, including humans. Recently, planarians have emerged as an attractive model in which to study regeneration. These animals are considering as in vivo plate, during which we can study the behavior and characristics of stem cells in their own niche. A variety of characteristic such as: simplicity, easy to manipulate experimentally, the existence of more than 100 years of literature, makes these animals an extraordinary model for regenerative medicine researches. Among planarians free-living freshwater hermaphrodite Schmidtea mediterranea has emerged as a suitable model system because it displays robust regenerative properties and, unlike most other planarians, it is a stable diploid with a genome size of about 4.8×10(8) base pairs, nearly half that of other common planarians. Planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of anybody region. neoblasts represent roughly 25~30 percent of all planarian cells and are scattered broadly through the parenchyma, being absent only from the animal head tips and the pharynx. Two models for neo-blast specification have been proposed; the naive model posits that all neoblasts are stem cells with the same potential and are a largely homogeneous population. PMID:26634061

  12. A regulatory program for excretory system regeneration in planarians

    PubMed Central

    Scimone, M. Lucila; Srivastava, Mansi; Bell, George W.; Reddien, Peter W.

    2011-01-01

    Planarians can regenerate any missing body part, requiring mechanisms for the production of organ systems in the adult, including their prominent tubule-based filtration excretory system called protonephridia. Here, we identify a set of genes, Six1/2-2, POU2/3, hunchback, Eya and Sall, that encode transcription regulatory proteins that are required for planarian protonephridia regeneration. During regeneration, planarian stem cells are induced to form a cell population in regeneration blastemas expressing Six1/2-2, POU2/3, Eya, Sall and Osr that is required for excretory system formation. POU2/3 and Six1/2-2 are essential for these precursor cells to form. Eya, Six1/2-2, Sall, Osr and POU2/3-related genes are required for vertebrate kidney development. We determined that planarian and vertebrate excretory cells express homologous proteins involved in reabsorption and waste modification. Furthermore, we identified novel nephridia genes. Our results identify a transcriptional program and cellular mechanisms for the regeneration of an excretory organ and suggest that metazoan excretory systems are regulated by genetic programs that share a common evolutionary origin. PMID:21937596

  13. Expression of Nephrin Homologue in the Freshwater Planarian, Dugesia japonica

    PubMed Central

    Nakamura, Tomomi; Takagi, Sota; Matsumoto, Midori; Tashiro, Fumio; Sakai, Tatsuo; Ichimura, Koichiro

    2014-01-01

    Excretory organs contain epithelial cells that form a filtration membrane specialized for ultrafiltration to produce primary urine. In vertebrates, the filtration membrane is made up of slit diaphragm (SD) formed by glomerular podocytes. Basal metazoans such as flatworms are also known have filtration epithelial cells, called flame cells, which exhibit SD-like structures. The molecular components of podocyte SD have been studied in detail, while those of the SD-like structures in basal metazoans including flatworms remain to be clarified. To determine whether the SD-like structures in flatworms have molecular components common to the SD in vertebrate podocytes, we examined the expression of gene homologue for mammalian nephrin, which encodes an essential transmembrane protein that participates in the formation of the SD, in a species of flatworms, planarian (Dugesia japonica). Flame cells were distributed throughout the entire body of the planarian, but the nephrin-expressing cells identified by in situ hybridization were mainly detected at body periphery excluding head region. The distribution pattern of nephrin-expressing cells was similar to that of proliferating cell nuclear antigen-expressing neoblasts, which are pluripotent stem cells characteristic to planarians. These findings indicated that the SD-like structures can be formed without the Nephrin protein in planarian flame cells. PMID:25859064

  14. Multiple Neuropeptide-Coding Genes Involved in Planarian Pharynx Extension.

    PubMed

    Shimoyama, Seira; Inoue, Takeshi; Kashima, Makoto; Agata, Kiyokazu

    2016-06-01

    Planarian feeding behavior involves three steps: moving toward food, extending the pharynx from their planarian's ventral side after arriving at the food, and ingesting the food through the pharynx. Although pharynx extension is a remarkable behavior, it remains unknown what neuronal cell types are involved in its regulation. To identify neurons involved in regulating pharynx extension, we quantitatively analyzed pharynx extension and sought to identify these neurons by RNA interference (RNAi) and in situ hybridization. This assay, when performed using planarians with amputation of various body parts, clearly showed that the head portion is indispensable for inducing pharynx extension. We thus tested the effects of knockdown of brain neurons such as serotonergic, GABAergic, and dopaminergic neurons by RNAi, but did not observe any effects on pharynx extension behavior. However, animals with RNAi of the Prohormone Convertase 2 (PC2, a neuropeptide processing enzyme) gene did not perform the pharynx extension behavior, suggesting the possible involvement of neuropeptide(s in the regulation of pharynx extension. We screened 24 neuropeptide-coding genes, analyzed their functions by RNAi using the pharynx extension assay system, and identified at least five neuropeptide genes involved in pharynx extension. These was expressed in different cells or neurons, and some of them were expressed in the brain, suggesting complex regulation of planarian feeding behavior by the nervous system. PMID:27268986

  15. Benzodiazepine inhibits anxiogenic-like response in cocaine or ethanol withdrawn planarians.

    PubMed

    Nayak, Sunil; Roberts, Adam; Bires, Kristofer; Tallarida, Christopher S; Kim, Erin; Wu, Michael; Rawls, Scott M

    2016-09-01

    Planarians spend less time in light versus dark environments. We hypothesized that planarians withdrawn from cocaine or ethanol would spend even less time in the light than drug-naive planarians and that a benzodiazepine would inhibit this response. Planarians pretreated in cocaine or ethanol were placed at the midline of a Petri dish containing spring water that was split evenly into dark and light compartments. Planarians withdrawn from cocaine (1, 10, 100 μmol/l) or ethanol (0.01%) spent less time in the light compartment than water controls; however, this withdrawal response to cocaine (100 μmol/l) or ethanol (0.01%) was abolished by clorazepate (0-100 μmol/l). These data suggest that planarians, similar to rodents, show benzodiazepine-sensitive, anxiogenic-like responses during cocaine or alcohol withdrawal. PMID:27028903

  16. Freshwater Planarians as an Alternative Animal Model for Neurotoxicology

    PubMed Central

    Hagstrom, Danielle; Cochet-Escartin, Olivier; Zhang, Siqi; Khuu, Cindy; Collins, Eva-Maria S.

    2015-01-01

    Traditional toxicology testing has relied on low-throughput, expensive mammalian studies; however, timely testing of the large number of environmental toxicants requires new in vitro and in vivo platforms for inexpensive medium- to high-throughput screening. Herein, we describe the suitability of the asexual freshwater planarian Dugesia japonica as a new animal model for the study of developmental neurotoxicology. As these asexual animals reproduce by binary fission, followed by regeneration of missing body structures within approximately 1 week, development and regeneration occur through similar processes allowing us to induce neurodevelopment “at will” through amputation. This short time scale and the comparable sizes of full and regenerating animals enable parallel experiments in adults and developing worms to determine development-specific aspects of toxicity. Because the planarian brain, despite its simplicity, is structurally and molecularly similar to the mammalian brain, we are able to ascertain neurodevelopmental toxicity that is relevant to humans. As a proof of concept, we developed a 5-step semiautomatic screening platform to characterize the toxicity of 9 known neurotoxicants (consisting of common solvents, pesticides, and detergents) and a neutral agent, glucose, and quantified effects on viability, stimulated and unstimulated behavior, regeneration, and brain structure. Comparisons of our findings with other alternative toxicology animal models, such as zebrafish larvae and nematodes, demonstrated that planarians are comparably sensitive to the tested chemicals. In addition, we found that certain compounds induced adverse effects specifically in developing animals. We thus conclude that planarians offer new complementary opportunities for developmental neurotoxicology animal models. PMID:26116028

  17. Freshwater Planarians as an Alternative Animal Model for Neurotoxicology.

    PubMed

    Hagstrom, Danielle; Cochet-Escartin, Olivier; Zhang, Siqi; Khuu, Cindy; Collins, Eva-Maria S

    2015-09-01

    Traditional toxicology testing has relied on low-throughput, expensive mammalian studies; however, timely testing of the large number of environmental toxicants requires new in vitro and in vivo platforms for inexpensive medium- to high-throughput screening. Herein, we describe the suitability of the asexual freshwater planarian Dugesia japonica as a new animal model for the study of developmental neurotoxicology. As these asexual animals reproduce by binary fission, followed by regeneration of missing body structures within approximately 1 week, development and regeneration occur through similar processes allowing us to induce neurodevelopment "at will" through amputation. This short time scale and the comparable sizes of full and regenerating animals enable parallel experiments in adults and developing worms to determine development-specific aspects of toxicity. Because the planarian brain, despite its simplicity, is structurally and molecularly similar to the mammalian brain, we are able to ascertain neurodevelopmental toxicity that is relevant to humans. As a proof of concept, we developed a 5-step semiautomatic screening platform to characterize the toxicity of 9 known neurotoxicants (consisting of common solvents, pesticides, and detergents) and a neutral agent, glucose, and quantified effects on viability, stimulated and unstimulated behavior, regeneration, and brain structure. Comparisons of our findings with other alternative toxicology animal models, such as zebrafish larvae and nematodes, demonstrated that planarians are comparably sensitive to the tested chemicals. In addition, we found that certain compounds induced adverse effects specifically in developing animals. We thus conclude that planarians offer new complementary opportunities for developmental neurotoxicology animal models. PMID:26116028

  18. Two FGFRL-Wnt circuits organize the planarian anteroposterior axis

    PubMed Central

    Scimone, M Lucila; Cote, Lauren E; Rogers, Travis; Reddien, Peter W

    2016-01-01

    How positional information instructs adult tissue maintenance is poorly understood. Planarians undergo whole-body regeneration and tissue turnover, providing a model for adult positional information studies. Genes encoding secreted and transmembrane components of multiple developmental pathways are predominantly expressed in planarian muscle cells. Several of these genes regulate regional identity, consistent with muscle harboring positional information. Here, single-cell RNA-sequencing of 115 muscle cells from distinct anterior-posterior regions identified 44 regionally expressed genes, including multiple Wnt and ndk/FGF receptor-like (ndl/FGFRL) genes. Two distinct FGFRL-Wnt circuits, involving juxtaposed anterior FGFRL and posterior Wnt expression domains, controlled planarian head and trunk patterning. ndl-3 and wntP-2 inhibition expanded the trunk, forming ectopic mouths and secondary pharynges, which independently extended and ingested food. fz5/8-4 inhibition, like that of ndk and wntA, caused posterior brain expansion and ectopic eye formation. Our results suggest that FGFRL-Wnt circuits operate within a body-wide coordinate system to control adult axial positioning. DOI: http://dx.doi.org/10.7554/eLife.12845.001 PMID:27063937

  19. A premeiotic function for boule in the planarian Schmidtea mediterranea.

    PubMed

    Iyer, Harini; Issigonis, Melanie; Sharma, Prashant P; Extavour, Cassandra G; Newmark, Phillip A

    2016-06-21

    Mutations in Deleted in Azoospermia (DAZ), a Y chromosome gene, are an important cause of human male infertility. DAZ is found exclusively in primates, limiting functional studies of this gene to its homologs: boule, required for meiotic progression of germ cells in invertebrate model systems, and Daz-like (Dazl), required for early germ cell maintenance in vertebrates. Dazl is believed to have acquired its premeiotic role in a vertebrate ancestor following the duplication and functional divergence of the single-copy gene boule. However, multiple homologs of boule have been identified in some invertebrates, raising the possibility that some of these genes may play other roles, including a premeiotic function. Here we identify two boule paralogs in the freshwater planarian Schmidtea mediterranea Smed-boule1 is necessary for meiotic progression of male germ cells, similar to the known function of boule in invertebrates. By contrast, Smed-boule2 is required for the maintenance of early male germ cells, similar to vertebrate Dazl To examine if Boule2 may be functionally similar to vertebrate Dazl, we identify and functionally characterize planarian homologs of human DAZL/DAZ-interacting partners and DAZ family mRNA targets. Finally, our phylogenetic analyses indicate that premeiotic functions of planarian boule2 and vertebrate Dazl evolved independently. Our study uncovers a premeiotic role for an invertebrate boule homolog and offers a tractable invertebrate model system for studying the premeiotic functions of the DAZ protein family. PMID:27330085

  20. Planarian GSK3s are involved in neural regeneration.

    PubMed

    Adell, Teresa; Marsal, Maria; Saló, Emili

    2008-02-01

    Glycogen synthase kinase-3 (GSK3) is a key element in several signaling cascades that is known to be involved in both patterning and neuronal organization. It is, therefore, a good candidate to play a role in neural regeneration in planarians. We report the characterization of three GSK3 genes in Schmidtea mediterranea. Phylogenetic analysis shows that Smed-GSK3.1 is highly conserved compared to GSK3 sequences from other species, whereas Smed-GSK3.2 and Smed-GSK3.3 are more divergent. Treatment of regenerating planarians with 1-azakenpaullone, a synthetic GSK3 inhibitor, suggests that planarian GSK3s are essential for normal differentiation and morphogenesis of the nervous system. Cephalic ganglia appear smaller and disconnected in 1-azakenpaullone-treated animals, whereas visual axons are ectopically projected, and the pharynx does not regenerate properly. This phenotype is consistent with a role for Smed-GSK3s in neuronal polarization and axonal growth. PMID:18202849

  1. pbx is required for pole and eye regeneration in planarians.

    PubMed

    Chen, Chun-Chieh G; Wang, Irving E; Reddien, Peter W

    2013-02-01

    Planarian regeneration involves regionalized gene expression that specifies the body plan. After amputation, planarians are capable of regenerating new anterior and posterior poles, as well as tissues polarized along the anterior-posterior, dorsal-ventral and medial-lateral axes. Wnt and several Hox genes are expressed at the posterior pole, whereas Wnt inhibitory genes, Fgf inhibitory genes, and prep, which encodes a TALE-family homeodomain protein, are expressed at the anterior pole. We found that Smed-pbx (pbx for short), which encodes a second planarian TALE-family homeodomain transcription factor, is required for restored expression of these genes at anterior and posterior poles during regeneration. Moreover, pbx(RNAi) animals gradually lose pole gene expression during homeostasis. By contrast, pbx was not required for initial anterior-posterior polarized responses to wounds, indicating that pbx is required after wound responses for development and maintenance of poles during regeneration and homeostatic tissue turnover. Independently of the requirement for pbx in pole regeneration, pbx is required for eye precursor formation and, consequently, eye regeneration and eye replacement in homeostasis. Together, these data indicate that pbx promotes pole formation of body axes and formation of regenerative progenitors for eyes. PMID:23318641

  2. Two FGFRL-Wnt circuits organize the planarian anteroposterior axis.

    PubMed

    Scimone, M Lucila; Cote, Lauren E; Rogers, Travis; Reddien, Peter W

    2016-01-01

    How positional information instructs adult tissue maintenance is poorly understood. Planarians undergo whole-body regeneration and tissue turnover, providing a model for adult positional information studies. Genes encoding secreted and transmembrane components of multiple developmental pathways are predominantly expressed in planarian muscle cells. Several of these genes regulate regional identity, consistent with muscle harboring positional information. Here, single-cell RNA-sequencing of 115 muscle cells from distinct anterior-posterior regions identified 44 regionally expressed genes, including multiple Wnt and ndk/FGF receptor-like (ndl/FGFRL) genes. Two distinct FGFRL-Wnt circuits, involving juxtaposed anterior FGFRL and posterior Wnt expression domains, controlled planarian head and trunk patterning. ndl-3 and wntP-2 inhibition expanded the trunk, forming ectopic mouths and secondary pharynges, which independently extended and ingested food. fz5/8-4 inhibition, like that of ndk and wntA, caused posterior brain expansion and ectopic eye formation. Our results suggest that FGFRL-Wnt circuits operate within a body-wide coordinate system to control adult axial positioning. PMID:27063937

  3. pbx is required for pole and eye regeneration in planarians

    PubMed Central

    Chen, Chun-Chieh G.; Wang, Irving E.; Reddien, Peter W.

    2013-01-01

    Planarian regeneration involves regionalized gene expression that specifies the body plan. After amputation, planarians are capable of regenerating new anterior and posterior poles, as well as tissues polarized along the anterior-posterior, dorsal-ventral and medial-lateral axes. Wnt and several Hox genes are expressed at the posterior pole, whereas Wnt inhibitory genes, Fgf inhibitory genes, and prep, which encodes a TALE-family homeodomain protein, are expressed at the anterior pole. We found that Smed-pbx (pbx for short), which encodes a second planarian TALE-family homeodomain transcription factor, is required for restored expression of these genes at anterior and posterior poles during regeneration. Moreover, pbx(RNAi) animals gradually lose pole gene expression during homeostasis. By contrast, pbx was not required for initial anterior-posterior polarized responses to wounds, indicating that pbx is required after wound responses for development and maintenance of poles during regeneration and homeostatic tissue turnover. Independently of the requirement for pbx in pole regeneration, pbx is required for eye precursor formation and, consequently, eye regeneration and eye replacement in homeostasis. Together, these data indicate that pbx promotes pole formation of body axes and formation of regenerative progenitors for eyes. PMID:23318641

  4. Cell Death and Tissue Remodeling in Planarian Regeneration

    PubMed Central

    Pellettieri, Jason; Fitzgerald, Patrick; Watanabe, Shigeki; Mancuso, Joel; Green, Douglas R.; Alvarado, Alejandro Sánchez

    2010-01-01

    Many long-lived organisms, including humans, can regenerate some adult tissues lost to physical injury or disease. Much of the previous research on mechanisms of regeneration has focused on adult stem cells, which give rise to new tissue necessary for the replacement of missing body parts. Here we report that apoptosis of differentiated cells complements stem cell division during regeneration in the planarian Schmidtea mediterranea. Specifically, we developed a whole-mount TUNEL assay that allowed us to document two dramatic increases in the rate of apoptosis following amputation – an intial localized response near the wound site and a subsequent systemic response that varies in magnitude depending on the type of fragment examined. The latter cell death response can be induced in uninjured organs, occurs in the absence of planarian stem cells, and can also be triggered by prolonged starvation. Taken together, our results implicate apoptosis in the restoration of proper anatomical scale and proportion through remodeling of existing tissues. We also report results from initial mechanistic studies of apoptosis in planarians, which revealed that a S. mediterranea homolog of the antiapoptotic gene BCL2 is required for cell survival in adult animals. We propose that apoptosis is a central mechanism working in concert with stem cell division to restore anatomical form and function during metazoan regeneration. PMID:19766622

  5. Planarians in toxicology. Responses of asexual Dugesia dorotocephala to selected metals

    SciTech Connect

    Kapu, M.M.; Schaeffer, D.J. )

    1991-08-01

    The planarian Dugesia dorotocephala is a freshwater invertebrate found in unpolluted flowing surface waters. Planarians have a sensitive nervous system with synapses and true brain and evidence these in a variety of social and response behaviors. The inclusion of planarians in a screening battery would provide improved sensitivity in detecting toxicity because planarians commonly respond to lower levels of contamination than do other species. Numerous toxicity test have been conducted to determine the acute and chronic effects of toxicants to provide data necessary for the development of water quality criteria. The appropriateness of Illinois water quality standards for metals was investigated using a 1-hr behavioral test based on the responses of the planarian D. dorotocephala. One possible difficulty with water quality standards for metals is that the standard for each metal is usually established without regard to the effects of other metals present in the receiving water.

  6. Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes

    PubMed Central

    2013-01-01

    Background The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments

  7. Planarian Body-Wall Muscle: Regeneration and Function beyond a Simple Skeletal Support

    PubMed Central

    Cebrià, Francesc

    2016-01-01

    The body-wall musculature of adult planarians consists of intricately organized muscle fibers, which after amputation are regenerated rapidly and with great precision through the proliferation and differentiation of pluripotent stem cells. These traits make the planarian body-wall musculature a potentially useful model for the study of cell proliferation, differentiation, and pattern formation. Planarian body-wall muscle shows some ambiguous features common to both skeletal and smooth muscle cells. However, its skeletal nature is implied by the expression of skeletal myosin heavy-chain genes and the myogenic transcription factor myoD. Where and when planarian stem cells become committed to the myogenic lineage during regeneration, how the new muscle cells are integrated into the pre-existing muscle net, and the identity of the molecular pathway controlling the myogenic gene program are key aspects of planarian muscle regeneration that need to be addressed. Expression of the conserved transcription factor myoD has been recently demonstrated in putative myogenic progenitors. Moreover, recent studies suggest that differentiated muscle cells may provide positional information to planarian stem cells during regeneration. Here, I review the limited available knowledge on planarian muscle regeneration. PMID:26904543

  8. Sucrose produces withdrawal and dopamine-sensitive reinforcing effects in planarians.

    PubMed

    Zhang, Charlie; Tallarida, Christopher S; Raffa, Robert B; Rawls, Scott M

    2013-03-15

    Sucrose produces physical dependence and reinforcing effects in rats. We hypothesized that similar effects could be demonstrated in planarians, the earliest animal with a centralized nervous system. We used two assays, one that quantifies withdrawal responses during drug absence as a reduction in motility and another that quantifies reinforcing effects using a conditioned place preference (CPP) design. In withdrawal experiments, planarians exposed to sucrose (1%) for 60 min and then tested in water for 5 min displayed reduced motility compared to water controls. Acute or continuous sucrose (1%) exposure did not affect motility. CPP experiments used a biased design to capitalize upon planarians' natural preference for the dark (pretest, sucrose conditioning in the light, posttest). Planarians conditioned with sucrose (1%) displayed a greater preference shift than sucrose-naïve planarians. Glucose (0.1, 1%), but not the non-digestible disaccharide lactulose (0.1, 1%), also produced a greater preference shift than water-exposed planarians. Development of sucrose-induced CPP was inhibited when sucrose (1%) conditioning was conducted in combination with dopamine receptor antagonists SCH 23390 (1 μM) or sulpiride (1 μM). These results suggest that the rewarding and reinforcing effects of sugar are highly conserved across species and that planarians offer an invertebrate model to provide insight into the pharmacological effects of sucrose and related sweeteners. PMID:23415661

  9. Planarian Body-Wall Muscle: Regeneration and Function beyond a Simple Skeletal Support.

    PubMed

    Cebrià, Francesc

    2016-01-01

    The body-wall musculature of adult planarians consists of intricately organized muscle fibers, which after amputation are regenerated rapidly and with great precision through the proliferation and differentiation of pluripotent stem cells. These traits make the planarian body-wall musculature a potentially useful model for the study of cell proliferation, differentiation, and pattern formation. Planarian body-wall muscle shows some ambiguous features common to both skeletal and smooth muscle cells. However, its skeletal nature is implied by the expression of skeletal myosin heavy-chain genes and the myogenic transcription factor myoD. Where and when planarian stem cells become committed to the myogenic lineage during regeneration, how the new muscle cells are integrated into the pre-existing muscle net, and the identity of the molecular pathway controlling the myogenic gene program are key aspects of planarian muscle regeneration that need to be addressed. Expression of the conserved transcription factor myoD has been recently demonstrated in putative myogenic progenitors. Moreover, recent studies suggest that differentiated muscle cells may provide positional information to planarian stem cells during regeneration. Here, I review the limited available knowledge on planarian muscle regeneration. PMID:26904543

  10. Basal bodies across eukaryotes series: basal bodies in the freshwater planarian Schmidtea mediterranea.

    PubMed

    Azimzadeh, Juliette; Basquin, Cyril

    2016-01-01

    The freshwater planarian Schmidtea mediterranea has recently emerged as a valuable model system to study basal bodies (BBs) and cilia. Planarians are free-living flatworms that use cilia beating at the surface of their ventral epidermis for gliding along substrates. The ventral epidermis is composed of multiciliated cells (MCCs) that are similar to the MCCs in the respiratory airways, the brain ventricles, and the oviducts in vertebrates. In the planarian epidermis, each cell assembles approximately eighty cilia that beat in a coordinate fashion across the tissue. The BBs that nucleate these cilia all assemble de novo during terminal differentiation of MCCs. The genome of the planarian S. mediterranea has been sequenced and efficient methods for targeting gene expression by RNA interference are available. Defects induced by perturbing the expression of BB proteins can be detected simply by analyzing the locomotion of planarians. BBs are present in large numbers and in predictable orientation, which greatly facilitates analyses by immunofluorescence and electron microscopy. The great ease in targeting gene expression and analyzing associated defects allowed to identify a set of proteins required for BB assembly and function in planarian MCCs. Future technological developments, including methods for transgenic expression in planarians and in related species, will achieve turning free-living flatworms into powerful model systems to study MCCs and the associated human pathologies. PMID:26998257

  11. Evolutionary Analysis of Mitogenomes from Parasitic and Free-Living Flatworms

    PubMed Central

    Frías-López, Cristina; Littlewood, D. Timothy J.; Rozas, Julio; Riutort, Marta

    2015-01-01

    Mitochondrial genomes (mitogenomes) are useful and relatively accessible sources of molecular data to explore and understand the evolutionary history and relationships of eukaryotic organisms across diverse taxonomic levels. The availability of complete mitogenomes from Platyhelminthes is limited; of the 40 or so published most are from parasitic flatworms (Neodermata). Here, we present the mitogenomes of two free-living flatworms (Tricladida): the complete genome of the freshwater species Crenobia alpina (Planariidae) and a nearly complete genome of the land planarian Obama sp. (Geoplanidae). Moreover, we have reanotated the published mitogenome of the species Dugesia japonica (Dugesiidae). This contribution almost doubles the total number of mtDNAs published for Tricladida, a species-rich group including model organisms and economically important invasive species. We took the opportunity to conduct comparative mitogenomic analyses between available free-living and selected parasitic flatworms in order to gain insights into the putative effect of life cycle on nucleotide composition through mutation and natural selection. Unexpectedly, we did not find any molecular hallmark of a selective relaxation in mitogenomes of parasitic flatworms; on the contrary, three out of the four studied free-living triclad mitogenomes exhibit higher A+T content and selective relaxation levels. Additionally, we provide new and valuable molecular data to develop markers for future phylogenetic studies on planariids and geoplanids. PMID:25793530

  12. THE HISTORY AND ENDURING CONTRIBUTIONS OF PLANARIANS TO THE STUDY OF ANIMAL REGENERATION

    PubMed Central

    Elliott, Sarah A.; Sánchez Alvarado, Alejandro

    2012-01-01

    Having an almost unlimited capacity to regenerate tissues lost to age and injury, planarians have long fascinated naturalists. In the Western hemisphere alone, their documented history spans more than 200 years. Planarians were described in the early 19th century as being “immortal under the edge of the knife,” and initial investigation of these remarkable animals was significantly influenced by studies of regeneration in other organisms and from the flourishing field of experimental embryology in the late 19th and early 20th centuries. This review strives to place the study of planarian regeneration into a broader historical context by focusing on the significance and evolution of knowledge in this field. It also synthesizes our current molecular understanding of the mechanisms of planarian regeneration uncovered since this animal’s relatively recent entrance into the molecular-genetic age. PMID:23799578

  13. Transcriptome analysis of the planarian eye identifies ovo as a specific regulator of eye regeneration

    PubMed Central

    Lapan, Sylvain W.; Reddien, Peter W.

    2013-01-01

    Summary Among the millions of invertebrate species with visual systems, the genetic basis of eye development and function is well understood only in Drosophila melanogaster. We describe an eye transcriptome for the planarian Schmidtea mediterranea. Planarian photoreceptors expressed orthologs of genes required for phototransduction and microvillus structure in Drosophila and vertebrates, and optic pigment cells expressed solute transporters and melanin synthesis enzymes similar to those active in the vertebrate retinal pigment epithelium. Orthologs of several planarian eye genes, such as bestrophin-1 and Usher syndrome genes, cause eye defects in mammals when perturbed and were not previously described to have roles in invertebrate eyes. Five previously undescribed planarian eye transcription factors were required for normal eye formation during head regeneration. In particular, a conserved, transcription factor-encoding ovo gene was expressed from the earliest stages of eye regeneration and was required for regeneration of all cell types of the eye. PMID:22884275

  14. Innate immune system and tissue regeneration in Planarians: An area ripe for exploration

    PubMed Central

    Peiris, T. Harshani; Hoyer, Katrina K.; Oviedo, Néstor J.

    2014-01-01

    The immune system has been implicated as an important modulator of tissue regeneration. However, the mechanisms driving injury-induced immune response and tissue repair remain poorly understood. For over 200 years, planarians have been a classical model for studies on tissue regeneration, but the planarian immune system and its potential role in repair is largely unknown. We found through comparative genomic analysis and data mining that planarians contain many potential homologs of the innate immune system that are activated during injury and repair of adult tissues. These findings support the notion that the relationship between adult tissue repair and the immune system is an ancient feature of basal Bilateria. Further analysis of the planarian immune system during regeneration could potentially add to our understanding of how the innate immune system and inflammatory responses interplay with regenerative signals to induce scar-less tissue repair in the context of the adult organism. PMID:25082737

  15. On the organ trail: insights into organ regeneration in the planarian.

    PubMed

    Roberts-Galbraith, Rachel H; Newmark, Phillip A

    2015-06-01

    Advances in stem cell biology have led to the derivation of diverse cell types, yet challenges remain in creating complex tissues and functional organs. Unlike humans, some animals regenerate all missing tissues and organs successfully after dramatic injuries. Studies of organisms with exceptional regenerative capacity, like planarians, could complement in vitro studies and reveal mechanistic themes underlying regeneration on the scale of whole organs and tissues. In this review, we outline progress in understanding planarian organ regeneration, with focus on recent studies of the nervous, digestive, and excretory systems. We further examine molecular mechanisms underlying establishment of diverse cell fates from the planarian stem cell pool. Finally, we explore conceptual directions for future studies of organ regeneration in planarians. PMID:25703843

  16. The EGFR signaling pathway controls gut progenitor differentiation during planarian regeneration and homeostasis.

    PubMed

    Barberán, Sara; Fraguas, Susanna; Cebrià, Francesc

    2016-06-15

    The planarian Schmidtea mediterranea maintains and regenerates all its adult tissues through the proliferation and differentiation of a single population of pluripotent adult stem cells (ASCs) called neoblasts. Despite recent advances, the mechanisms regulating ASC differentiation into mature cell types are poorly understood. Here, we show that silencing of the planarian EGF receptor egfr-1 by RNA interference (RNAi) impairs gut progenitor differentiation into mature cells, compromising gut regeneration and maintenance. We identify a new putative EGF ligand, nrg-1, the silencing of which phenocopies the defects observed in egfr-1(RNAi) animals. These findings indicate that egfr-1 and nrg-1 promote gut progenitor differentiation, and are thus essential for normal cell turnover and regeneration in the planarian gut. Our study demonstrates that the EGFR signaling pathway is an important regulator of ASC differentiation in planarians. PMID:27122174

  17. miR-71b regulation of insulin/IGF-1 signaling during starvation in planarians.

    PubMed

    Wu, Y Y; Zhao, J M; Liu, Q; Guo, Q; Liu, Z; Wang, X X; Wang, C Y; Li, R Y; Zhang, Y Z; Zhang, S T

    2015-01-01

    Planarians, which have a large population of stem cells called neoblasts, are molecularly tractable model systems used in the study of regeneration. However, planarians have strong resistance to hunger and have developed growth arrest strategies. For example, they can change their size and undergo growth regression during starvation periods. The results of the current study show that the microRNA, miR-71b, and the insulin/IGF-1 signaling pathway have important functions in the development of starvation-induced planarians. We demonstrate tissue-specific expression of miR-71b using in situ hybridization. By employing real-time polymerase chain reaction, we provide evidence that miR-71b is upregulated in starvation-induced planarians. Furthermore, we validate and verify the target genes of miR-71b. PMID:26505338

  18. Neoblast Specialization in Regeneration of the Planarian Schmidtea mediterranea

    PubMed Central

    Scimone, M. Lucila; Kravarik, Kellie M.; Lapan, Sylvain W.; Reddien, Peter W.

    2014-01-01

    Summary Planarians can regenerate any missing body part in a process requiring dividing cells called neoblasts. Historically, neoblasts have largely been considered a homogeneous stem cell population. Most studies, however, analyzed neoblasts at the population rather than the single-cell level, leaving the degree of heterogeneity in this population unresolved. We combined RNA sequencing of neoblasts from wounded planarians with expression screening and identified 33 transcription factors transcribed in specific differentiated cells and in small fractions of neoblasts during regeneration. Many neoblast subsets expressing distinct tissue-associated transcription factors were present, suggesting candidate specification into many lineages. Consistent with this possibility, klf, pax3/7, and FoxA were required for the differentiation of cintillo-expressing sensory neurons, dopamine-β-hydroxylase-expressing neurons, and the pharynx, respectively. Together, these results suggest that specification of cell fate for most-to-all regenerative lineages occurs within neoblasts, with regenerative cells of blastemas being generated from a highly heterogeneous collection of lineage-specified neoblasts. PMID:25254346

  19. Characterization of the complete mitochondrial genomes from Polycladida (Platyhelminthes) using next-generation sequencing.

    PubMed

    Aguado, M Teresa; Grande, Cristina; Gerth, Michael; Bleidorn, Christoph; Noreña, Carolina

    2016-01-10

    The complete mitochondrial genomes of three polycladids, the acotylean Hoploplana elisabelloi and the cotyleans Enchiridium sp. and Prosthiostomum siphunculus have been assembled with high coverage from Illumina sequencing data. The mt genomes contain 36 genes including 12 of the 13 protein-coding genes characteristic for metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. Gene annotation, gene order, genetic code, start and stop codons and codon bias have been identified. In comparison with the well investigated parasitic Neodermata, our analysis reveals a great diversity of gene orders within Polycladida and Platyhelminthes in general. By analyzing representative genomes of the main groups of Platyhelminthes we explored the phylogenetic relationships of this group. The phylogenetic analyses strongly supported the monophyly of Polycladida, and based on a small taxon sampling suggest the monophyly of Acotylea and Cotylea. PMID:26325071

  20. Alternative flow cytometry strategies to analyze stem cells and cell death in planarians

    PubMed Central

    Peiris, Tanuja Harshani; García‐Ojeda, Marcos E.

    2016-01-01

    Abstract Planarians possess remarkable stem cell populations that continuously support cellular turnover and are instrumental in the regeneration of tissues upon injury. Cellular turnover and tissue regeneration in planarians rely on the proper integration of local and systemic signals that regulate cell proliferation and cell death. Thus, understanding the signals controlling cellular proliferation and cell death in planarians could provide valuable insights for maintenance of adult body homeostasis and the biology of regeneration. Flow cytometry techniques have been utilized widely to identify, isolate, and characterize planarian stem cell populations. We developed alternative flow cytometry strategies that reduce the number of reagents and the time of sample preparation to analyze stem cells and cell death in planarians. The sensitivity of these methods is validated with functional studies using RNA interference and treatment with  γ irradiation or stressful conditions that are known to trigger cell death. Altogether, we provide a community resource intended to minimize adverse effects during ex vivo studies of stem cells and cell death in planarians. PMID:27307993

  1. PlanMine--a mineable resource of planarian biology and biodiversity.

    PubMed

    Brandl, Holger; Moon, HongKee; Vila-Farré, Miquel; Liu, Shang-Yun; Henry, Ian; Rink, Jochen C

    2016-01-01

    Planarian flatworms are in the midst of a renaissance as a model system for regeneration and stem cells. Besides two well-studied model species, hundreds of species exist worldwide that present a fascinating diversity of regenerative abilities, tissue turnover rates, reproductive strategies and other life history traits. PlanMine (http://planmine.mpi-cbg.de/) aims to accomplish two primary missions: First, to provide an easily accessible platform for sharing, comparing and value-added mining of planarian sequence data. Second, to catalyze the comparative analysis of the phenotypic diversity amongst planarian species. Currently, PlanMine houses transcriptomes independently assembled by our lab and community contributors. Detailed assembly/annotation statistics, a custom-developed BLAST viewer and easy export options enable comparisons at the contig and assembly level. Consistent annotation of all transcriptomes by an automated pipeline, the integration of published gene expression information and inter-relational query tools provide opportunities for mining planarian gene sequences and functions. For inter-species comparisons, we include transcriptomes of, so far, six planarian species, along with images, expert-curated information on their biology and pre-calculated cross-species sequence homologies. PlanMine is based on the popular InterMine system in order to make the rich biology of planarians accessible to the general life sciences research community. PMID:26578570

  2. PlanMine – a mineable resource of planarian biology and biodiversity

    PubMed Central

    Brandl, Holger; Moon, HongKee; Vila-Farré, Miquel; Liu, Shang-Yun; Henry, Ian; Rink, Jochen C.

    2016-01-01

    Planarian flatworms are in the midst of a renaissance as a model system for regeneration and stem cells. Besides two well-studied model species, hundreds of species exist worldwide that present a fascinating diversity of regenerative abilities, tissue turnover rates, reproductive strategies and other life history traits. PlanMine (http://planmine.mpi-cbg.de/) aims to accomplish two primary missions: First, to provide an easily accessible platform for sharing, comparing and value-added mining of planarian sequence data. Second, to catalyze the comparative analysis of the phenotypic diversity amongst planarian species. Currently, PlanMine houses transcriptomes independently assembled by our lab and community contributors. Detailed assembly/annotation statistics, a custom-developed BLAST viewer and easy export options enable comparisons at the contig and assembly level. Consistent annotation of all transcriptomes by an automated pipeline, the integration of published gene expression information and inter-relational query tools provide opportunities for mining planarian gene sequences and functions. For inter-species comparisons, we include transcriptomes of, so far, six planarian species, along with images, expert-curated information on their biology and pre-calculated cross-species sequence homologies. PlanMine is based on the popular InterMine system in order to make the rich biology of planarians accessible to the general life sciences research community. PMID:26578570

  3. The use of lectins as markers for differentiated secretory cells in planarians.

    PubMed

    Zayas, Ricardo M; Cebrià, Francesc; Guo, Tingxia; Feng, Junjie; Newmark, Phillip A

    2010-11-01

    Freshwater planarians have reemerged as excellent models to investigate mechanisms underlying regeneration. The introduction of molecular tools has facilitated the study of planarians, but cell- and tissue-specific markers are still needed to examine differentiation of most cell types. Here we report the utility of fluorescent lectin-conjugates to label tissues in the planarian Schmidtea mediterranea. We show that 16 lectin-conjugates stain planarian cells or tissues; 13 primarily label the secretory cells, their cytoplasmic projections, and terminal pores. Thus, we examined regeneration of the secretory system using lectin markers and functionally characterized two genes expressed in the secretory cells: marginal adhesive gland-1 (mag-1) and Smed-reticulocalbin1 (Smed-rcn1). RNAi knockdown of these genes caused a dramatic reduction of secretory cell lectin staining, suggesting a role for mag-1 and Smed-rcn1 in secretory cell differentiation. Our results provide new insights into planarian secretory system regeneration and add new markers for labeling several planarian tissues. PMID:20865784

  4. Planarian PTEN homologs regulate stem cells and regeneration through TOR signaling.

    PubMed

    Oviedo, Néstor J; Pearson, Bret J; Levin, Michael; Sánchez Alvarado, Alejandro

    2008-01-01

    We have identified two genes, Smed-PTEN-1 and Smed-PTEN-2, capable of regulating stem cell function in the planarian Schmidtea mediterranea. Both genes encode proteins homologous to the mammalian tumor suppressor, phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Inactivation of Smed-PTEN-1 and -2 by RNA interference (RNAi) in planarians disrupts regeneration, and leads to abnormal outgrowths in both cut and uncut animals followed soon after by death (lysis). The resulting phenotype is characterized by hyperproliferation of neoblasts (planarian stem cells), tissue disorganization and a significant accumulation of postmitotic cells with impaired differentiation capacity. Further analyses revealed that rapamycin selectively prevented such accumulation without affecting the normal neoblast proliferation associated with physiological turnover and regeneration. In animals in which PTEN function is abrogated, we also detected a significant increase in the number of cells expressing the planarian Akt gene homolog (Smed-Akt). However, functional abrogation of Smed-Akt in Smed-PTEN RNAi-treated animals does not prevent cell overproliferation and lethality, indicating that functional abrogation of Smed-PTEN is sufficient to induce abnormal outgrowths. Altogether, our data reveal roles for PTEN in the regulation of planarian stem cells that are strikingly conserved to mammalian models. In addition, our results implicate this protein in the control of stem cell maintenance during the regeneration of complex structures in planarians. PMID:19048075

  5. Sucrose produces withdrawal and dopamine-sensitive reinforcing effects in planarians

    PubMed Central

    Zhang, Charlie; Tallarida, Christopher S.; Raffa, Robert B.; Rawls, Scott M.

    2014-01-01

    Sucrose produces physical dependence and reinforcing effects in rats. We hypothesized that similar effects could be demonstrated in planarians, the earliest animal with a centralized nervous system. We used two assays, one that quantifies withdrawal responses during drug absence as a reduction in motility and another that quantifies reinforcing effects using a conditioned place preference (CPP) design. In withdrawal experiments, planarians exposed to sucrose (1%) for 60 min and then tested in water for 5 min displayed reduced motility compared to water controls. Acute or continuous sucrose (1%) exposure did not affect motility. CPP experiments used a biased design to capitalize upon planarians’ natural preference for the dark (pretest, sucrose conditioning in the light, posttest). Planarians conditioned with sucrose (1%) displayed a greater preference shift than sucrose-naïve planarians. Glucose (0.1, 1%), but not the non-digestible disaccharide lactulose (0.1, 1%), also produced a greater preference shift than water-exposed planarians. Development of sucrose-induced CPP was inhibited when sucrose (1%) conditioning was conducted in combination with dopamine receptor antagonists SCH 23390 (1 µM) or sulpiride (1 µM). These results suggest that rewarding and reinforcing effects of sugar are highly conserved across species and that planarians offer an invertebrate model to provide insight into the pharmacological effects of sucrose and related sweeteners. PMID:23415661

  6. Simple blood-feeding method for live imaging of gut tube remodeling in regenerating planarians.

    PubMed

    Hosoda, Kazutaka; Morimoto, Mizuki; Motoishi, Minako; Nishimura, Osamu; Agata, Kiyokazu; Umesono, Yoshihiko

    2016-04-01

    Live cell imaging is a powerful technique to study cellular dynamics in vivo during animal development and regeneration. However, few live imaging methods have been reported for studying planarian regeneration. Here, we developed a simple method for steady visualization of gut tube remodeling during regeneration of a living freshwater planarian, Dugesia japonica. When planarians were fed blood several times, gut branches were well-visualized in living intact animals under normal bright-field illumination. Interestingly, tail fragments derived from these colored planarians enabled successive observation of the processes of the formation of a single anterior gut branch in the prepharyngeal region from the preexisting two posterior gut branches in the same living animals during head regeneration. Furthermore, we combined this method and RNA interference (RNAi) and thereby showed that a D. japonica raf-related gene (DjrafA) and mek-related gene (DjmekA) we identified both play a major role in the activation of extracellular signal-regulated kinase (ERK) signaling during planarian regeneration, as indicated by their RNAi-induced defects on gut tube remodeling in a time-saving initial screening using blood-feeding without immunohistochemical detection of the gut. Thus, this blood-feeding method is useful for live imaging of gut tube remodeling, and provides an advance for the field of regeneration study in planarians. PMID:26948408

  7. Alternative flow cytometry strategies to analyze stem cells and cell death in planarians.

    PubMed

    Peiris, Tanuja Harshani; García-Ojeda, Marcos E; Oviedo, Néstor J

    2016-04-01

    Planarians possess remarkable stem cell populations that continuously support cellular turnover and are instrumental in the regeneration of tissues upon injury. Cellular turnover and tissue regeneration in planarians rely on the proper integration of local and systemic signals that regulate cell proliferation and cell death. Thus, understanding the signals controlling cellular proliferation and cell death in planarians could provide valuable insights for maintenance of adult body homeostasis and the biology of regeneration. Flow cytometry techniques have been utilized widely to identify, isolate, and characterize planarian stem cell populations. We developed alternative flow cytometry strategies that reduce the number of reagents and the time of sample preparation to analyze stem cells and cell death in planarians. The sensitivity of these methods is validated with functional studies using RNA interference and treatment with  γ irradiation or stressful conditions that are known to trigger cell death. Altogether, we provide a community resource intended to minimize adverse effects during ex vivo studies of stem cells and cell death in planarians. PMID:27307993

  8. Topiramate antagonism of L-glutamate-induced paroxysms in planarians

    PubMed Central

    Raffa, Robert B.; Finno, Kristin E.; Tallarida, Christopher S.; Rawls, Scott M.

    2010-01-01

    We recently reported that NMDA (N-Methyl-D-aspartate) and AMPA (α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid) induce concentration-dependent paroxysms in planarians (Dugesia dorotocephala). Since the postulated mechanisms of action of the sulfamate-substituted monosaccharide antiepileptic drug topiramate include inhibition of glutamate-activated ion channels, we tested the hypothesis that topiramate would inhibit glutamate-induced paroxysms in our model. We demonstrate that: (1) L-glutamate (1–10 mM), but not D-glutamate, induced dose-related paroxysms, and that (2) topiramate dose-relatedly (0.3–3 mM) inhibited L-glutamate-induced paroxysms. These results provide further evidence of a topiramate-sensitive glutamate receptor-mediated activity in this model. PMID:20863783

  9. nanos function is essential for development and regeneration of planarian germ cells.

    PubMed

    Wang, Yuying; Zayas, Ricardo M; Guo, Tingxia; Newmark, Phillip A

    2007-04-01

    Germ cells are required for the successful propagation of sexually reproducing species. Understanding the mechanisms by which these cells are specified and how their totipotency is established and maintained has important biomedical and evolutionary implications. Freshwater planarians serve as fascinating models for studying these questions. They can regenerate germ cells from fragments of adult tissues that lack reproductive structures, suggesting that inductive signaling is involved in planarian germ cell specification. To study the development and regeneration of planarian germ cells, we have functionally characterized an ortholog of nanos, a gene required for germ cell development in diverse organisms, from Schmidtea mediterranea. In the hermaphroditic strain of this species, Smed-nanos mRNA is detected in developing, regenerating, and mature ovaries and testes. However, it is not detected in the vast majority of newly hatched planarians or in small tissue fragments that will ultimately regenerate germ cells, consistent with an epigenetic origin of germ cells. We show that Smed-nanos RNA interference (RNAi) results in failure to develop, regenerate, or maintain gonads in sexual planarians. Unexpectedly, Smed-nanos mRNA is also detected in presumptive testes primordia of asexual individuals that reproduce strictly by fission. These presumptive germ cells are lost after Smed-nanos RNAi, suggesting that asexual planarians specify germ cells, but their differentiation is blocked downstream of Smed-nanos function. Our results reveal a conserved function of nanos in germ cell development in planarians and suggest that these animals will serve as useful models for dissecting the molecular basis of epigenetic germ cell specification. PMID:17376870

  10. Land Planarian Assemblages in Protected Areas of the Interior Atlantic Forest: Implications for Conservation

    PubMed Central

    Negrete, Lisandro; Colpo, Karine D.; Brusa, Francisco

    2014-01-01

    Land planarians are an interesting group of free-living flatworms that can be useful as bioindicators because of their high sensitivity to environmental changes and low dispersal capacity. In this study, we describe and compare assemblages of land planarians from areas with different conservation degrees of the Interior Atlantic Forest (Misiones, Argentina), and assess factors that could be related to their abundance and richness. Eight sites were tracked in search of land planarians in Reserva de Vida Silvestre Urugua-í (RVSU) and Campo Anexo Manuel Belgrano (CAMB). Diurnal and nocturnal surveys were performed in each site along nine sampling campaigns. We collected 237 individuals belonging to 18 species of the subfamily Geoplaninae. All sites were dominated by Geoplana sp. 1 and Pasipha hauseri. The richness estimators showed that there would be more species in RVSU than in CAMB. The abundance and richness of land planarians was high during the night and after rainfalls, suggesting an increased activity of flatworms under such conditions. The abundance and richness of land planarians were also related to the conservation condition of the sites. Disturbed sites showed less abundance and richness, and were segregated from non-disturbed ones by nmMDS analysis. Beta diversity between sites was higher than expected, indicating that the species turnover between sites contributed more to the total richness (gamma diversity) than the alpha diversity. PMID:24598934

  11. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    PubMed Central

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  12. Regeneration and maintenance of the planarian midline is regulated by a slit orthologue.

    PubMed

    Cebrià, Francesc; Guo, Tingxia; Jopek, Jessica; Newmark, Phillip A

    2007-07-15

    Several families of evolutionarily conserved axon guidance cues orchestrate the precise wiring of the nervous system during embryonic development. The remarkable plasticity of freshwater planarians provides the opportunity to study these molecules in the context of neural regeneration and maintenance. Here we characterize a homologue of the Slit family of guidance cues from the planarian Schmidtea mediterranea. Smed-slit is expressed along the planarian midline, in both dorsal and ventral domains. RNA interference (RNAi) targeting Smed-slit results in the collapse of many newly regenerated tissues at the midline; these include the cephalic ganglia, ventral nerve cords, photoreceptors, and the posterior digestive system. Surprisingly, Smed-slit RNAi knockdown animals also develop morphologically distinguishable, ectopic neural structures near the midline in uninjured regions of intact and regenerating planarians. These results suggest that Smed-slit acts not only as a repulsive cue required for proper midline formation during regeneration but that it may also act to regulate the behavior of neural precursors at the midline in intact planarians. PMID:17553481

  13. EGFR signaling regulates cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis.

    PubMed

    Fraguas, Susanna; Barberán, Sara; Cebrià, Francesc

    2011-06-01

    Similarly to development, the process of regeneration requires that cells accurately sense and respond to their external environment. Thus, intrinsic cues must be integrated with signals from the surrounding environment to ensure appropriate temporal and spatial regulation of tissue regeneration. Identifying the signaling pathways that control these events will not only provide insights into a fascinating biological phenomenon but may also yield new molecular targets for use in regenerative medicine. Among classical models to study regeneration, freshwater planarians represent an attractive system in which to investigate the signals that regulate cell proliferation and differentiation, as well as the proper patterning of the structures being regenerated. Recent studies in planarians have begun to define the role of conserved signaling pathways during regeneration. Here, we extend these analyses to the epidermal growth factor (EGF) receptor pathway. We report the characterization of three epidermal growth factor (EGF) receptors in the planarian Schmidtea mediterranea. Silencing of these genes by RNA interference (RNAi) yielded multiple defects in intact and regenerating planarians. Smed-egfr-1(RNAi) resulted in decreased differentiation of eye pigment cells, abnormal pharynx regeneration and maintenance, and the development of dorsal outgrowths. In contrast, Smed-egfr-3(RNAi) animals produced smaller blastemas associated with abnormal differentiation of certain cell types. Our results suggest important roles for the EGFR signaling in controlling cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. PMID:21458439

  14. iTRAQ-Based Quantitative Proteomic Analysis of the Initiation of Head Regeneration in Planarians

    PubMed Central

    Geng, Xiaofang; Wang, Gaiping; Qin, Yanli; Zang, Xiayan; Li, Pengfei; Geng, Zhi; Xue, Deming; Dong, Zimei; Ma, Kexue; Chen, Guangwen; Xu, Cunshuan

    2015-01-01

    The planarian Dugesia japonica has amazing ability to regenerate a head from the anterior ends of the amputated stump with maintenance of the original anterior-posterior polarity. Although planarians present an attractive system for molecular investigation of regeneration and research has focused on clarifying the molecular mechanism of regeneration initiation in planarians at transcriptional level, but the initiation mechanism of planarian head regeneration (PHR) remains unclear at the protein level. Here, a global analysis of proteome dynamics during the early stage of PHR was performed using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics strategy, and our data are available via ProteomeXchange with identifier PXD002100. The results showed that 162 proteins were differentially expressed at 2 h and 6 h following amputation. Furthermore, the analysis of expression patterns and functional enrichment of the differentially expressed proteins showed that proteins involved in muscle contraction, oxidation reduction and protein synthesis were up-regulated in the initiation of PHR. Moreover, ingenuity pathway analysis showed that predominant signaling pathways such as ILK, calcium, EIF2 and mTOR signaling which were associated with cell migration, cell proliferation and protein synthesis were likely to be involved in the initiation of PHR. The results for the first time demonstrated that muscle contraction and ILK signaling might played important roles in the initiation of PHR at the global protein level. The findings of this research provide a molecular basis for further unraveling the mechanism of head regeneration initiation in planarians. PMID:26131905

  15. Land planarian assemblages in protected areas of the interior atlantic forest: implications for conservation.

    PubMed

    Negrete, Lisandro; Colpo, Karine D; Brusa, Francisco

    2014-01-01

    Land planarians are an interesting group of free-living flatworms that can be useful as bioindicators because of their high sensitivity to environmental changes and low dispersal capacity. In this study, we describe and compare assemblages of land planarians from areas with different conservation degrees of the Interior Atlantic Forest (Misiones, Argentina), and assess factors that could be related to their abundance and richness. Eight sites were tracked in search of land planarians in Reserva de Vida Silvestre Urugua-í (RVSU) and Campo Anexo Manuel Belgrano (CAMB). Diurnal and nocturnal surveys were performed in each site along nine sampling campaigns. We collected 237 individuals belonging to 18 species of the subfamily Geoplaninae. All sites were dominated by Geoplana sp. 1 and Pasipha hauseri. The richness estimators showed that there would be more species in RVSU than in CAMB. The abundance and richness of land planarians was high during the night and after rainfalls, suggesting an increased activity of flatworms under such conditions. The abundance and richness of land planarians were also related to the conservation condition of the sites. Disturbed sites showed less abundance and richness, and were segregated from non-disturbed ones by nmMDS analysis. Beta diversity between sites was higher than expected, indicating that the species turnover between sites contributed more to the total richness (gamma diversity) than the alpha diversity. PMID:24598934

  16. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

    PubMed

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  17. Planarian myosin essential light chain is involved in the formation of brain lateral branches during regeneration.

    PubMed

    Yu, Shuying; Chen, Xuhui; Yuan, Zuoqing; Zhou, Luming; Pang, Qiuxiang; Mao, Bingyu; Zhao, Bosheng

    2015-08-01

    The myosin essential light chain (ELC) is a structure component of the actomyosin cross-bridge, however, the functions in the central nervous system (CNS) development and regeneration remain poorly understood. Planarian Dugesia japonica has revealed fundamental mechanisms and unique aspects of neuroscience and neuroregeneration. In this study, the cDNA DjElc, encoding a planarian essential light chain of myosin, was identified from the planarian Dugesia japonica cDNA library. It encodes a deduced protein with highly conserved functionally domains EF-Hand and Ca(2+) binding sites that shares significant similarity with other members of ELC. Whole mount in situ hybridization studies show that DjElc expressed in CNS during embryonic development and regeneration of adult planarians. Loss of function of DjElc by RNA interference during planarian regeneration inhibits brain lateral branches regeneration completely. In conclusion, these results demonstrated that DjElc is required for maintenance of neurons and neurite outgrowth, particularly for involving the brain later branch regeneration. PMID:25585662

  18. Heterogeneity of chromatoid bodies in adult pluripotent stem cells of planarian Dugesia japonica.

    PubMed

    Kashima, Makoto; Kumagai, Nobuyoshi; Agata, Kiyokazu; Shibata, Norito

    2016-02-01

    The robust regenerative ability of planarians is known to be dependent on adult pluripotent stem cells called neoblasts. One of the morphological features of neoblasts is cytoplasmic ribonucleoprotein granules (chromatoid bodies: CBs), which resemble germ granules present in germline cells in other animals. Previously, we showed by immuno-electron microscopic analysis that DjCBC-1, a planarian Me31B/Dhh1/DDX6 homologue, which is a component of ribonucleoprotein granules, was localized in CBs in the planarian Dugesia japonica. Also, recently it was reported using another planarian species that Y12 antibody recognizing symmetrical dimethylarginine (sDMA) specifically binds to CBs in which histone mRNA is co-localized. Here, we showed by double immunostaining and RNA interference (RNAi) that DjCBC-1-containing CBs and Y12-immunoreactive CBs are distinct structures, suggesting that CBs are composed of heterogeneous populations. We also found that the Y12-immunoreactive CBs specifically contained a cytoplasmic type of planarian PIWI protein (DjPiwiC). We revealed by RNAi experiments that Y12-immunoreactive CBs may have anti-transposable element activity involving the DjPiwiC protein in the neoblasts. PMID:26857694

  19. Behavioural responses of freshwater planarians after short-term exposure to the insecticide chlorantraniliprole.

    PubMed

    Rodrigues, Andreia C M; Henriques, Jorge F; Domingues, Inês; Golovko, Oksana; Žlábek, Vladimír; Barata, Carlos; Soares, Amadeu M V M; Pestana, João L T

    2016-01-01

    Recent advances in video tracking technologies provide the tools for a sensitive and reproducible analysis of invertebrate activity under stressful conditions nurturing the field of behavioural ecotoxicology. This study aimed to evaluate behavioural responses of the freshwater planarian Dugesia subtentaculata exposed to a model compound, chlorantraniliprole (CAP). This compound is an anthranilic diamide insecticide and due to its neurotoxic action can, at low concentrations, impair behaviour of exposed organisms. Behavioural endpoints measured included feeding and locomotor activities. Feeding responses were based on planarian predatory behaviour using Chironomus riparius larvae as prey. Locomotion was measured by the traditional planarian locomotor velocity (pLMV) assay and additionally using an automated video tracking system using a Zebrabox(®) (Viewpoint, France) device. While feeding and pLMV were significantly impaired at 131.7μg/L CAP, the video tracking system showed that total distance covered by planarians was significantly reduced at concentrations as low as 26.2μg/L CAP. Our results show that more advanced automated video recording systems can be used in the development of sensitive bioassays allowing a reliable, time- and cost-effective quantification of behaviour in aquatic invertebrates. Due to their ecological relevance, behavioural responses should not be disregarded in risk assessment strategies and we advocate the suitability of planarians as suitable organisms for behavioural ecotoxicological studies. PMID:26561438

  20. A molecular wound response program associated with regeneration initiation in planarians

    PubMed Central

    Wenemoser, Danielle; Lapan, Sylvain W.; Wilkinson, Alex W.; Bell, George W.; Reddien, Peter W.

    2012-01-01

    Planarians are capable of regenerating any missing body part and present an attractive system for molecular investigation of regeneration initiation. The gene activation program that occurs at planarian wounds to coordinate regenerative responses remains unknown. We identified a large set of wound-induced genes during regeneration initiation in planarians. Two waves of wound-induced gene expression occurred in differentiated tissues. The first wave includes conserved immediate early genes. Many second-wave genes encode conserved patterning factors required for proper regeneration. Genes of both classes were generally induced by wounding, indicating that a common initial gene expression program is triggered regardless of missing tissue identity. Planarian regeneration uses a population of regenerative cells (neoblasts), including pluripotent stem cells. A class of wound-induced genes was activated directly within neoblasts, including the Runx transcription factor-encoding runt-1 gene. runt-1 was required for specifying different cell types during regeneration, promoting heterogeneity in neoblasts near wounds. Wound-induced gene expression in neoblasts, including that of runt-1, required SRF (serum response factor) and sos-1. Taken together, these data connect wound sensation to the activation of specific cell type regeneration programs in neoblasts. Most planarian wound-induced genes are conserved across metazoans, and identified genes and mechanisms should be important broadly for understanding wound signaling and regeneration initiation. PMID:22549959

  1. An RNAi screen reveals intestinal regulators of branching morphogenesis, differentiation, and stem cell proliferation in planarians

    PubMed Central

    Forsthoefel, David J.; James, Noelle P.; Escobar, David J.; Stary, Joel M.; Vieira, Ana P.; Waters, Forrest A.; Newmark, Phillip A.

    2012-01-01

    SUMMARY Planarians grow and regenerate organs by coordinating proliferation and differentiation of pluripotent stem cells with remodeling of post-mitotic tissues. Understanding how these processes are orchestrated requires characterizing cell type-specific gene expression programs and their regulation during regeneration and homeostasis. To this end, we analyzed the expression profile of planarian intestinal phagocytes, cells responsible for digestion and nutrient storage/distribution. Utilizing RNA interference, we identified cytoskeletal regulators required for intestinal branching morphogenesis, and a modulator of bioactive sphingolipid metabolism, ceramide synthase, required for the production of functional phagocytes. Additionally, we found that a gut-enriched homeobox transcription factor, nkx-2.2, is required for somatic stem cell proliferation, suggesting a niche-like role for phagocytes. Identification of evolutionarily conserved regulators of intestinal branching, differentiation, and stem cell dynamics demonstrates the utility of the planarian digestive system as a model for elucidating the mechanisms controlling post-embryonic organogenesis. PMID:23079596

  2. Planarian MBD2/3 is required for adult stem cell pluripotency independently of DNA methylation☆

    PubMed Central

    Jaber-Hijazi, Farah; Lo, Priscilla J.K.P.; Mihaylova, Yuliana; Foster, Jeremy M.; Benner, Jack S.; Tejada Romero, Belen; Chen, Chen; Malla, Sunir; Solana, Jordi; Ruzov, Alexey; Aziz Aboobaker, A.

    2013-01-01

    Planarian adult stem cells (pASCs) or neoblasts represent an ideal system to study the evolution of stem cells and pluripotency as they underpin an unrivaled capacity for regeneration. We wish to understand the control of differentiation and pluripotency in pASCs and to understand how conserved, convergent or divergent these mechanisms are across the Bilateria. Here we show the planarian methyl-CpG Binding Domain 2/3 (mbd2/3) gene is required for pASC differentiation during regeneration and tissue homeostasis. The genome does not have detectable levels of 5-methylcytosine (5mC) and we find no role for a potential DNA methylase. We conclude that MBD proteins may have had an ancient role in broadly controlling animal stem cell pluripotency, but that DNA methylation is not involved in planarian stem cell differentiation. PMID:24063805

  3. Expression of hsp90 mediates cytoprotective effects in the gastrodermis of planarians

    PubMed Central

    Conte, Maria; Isolani, Maria Emilia; Deri, Paolo; Mannini, Linda

    2010-01-01

    Heat shock proteins (HSPs) play a crucial role in the protection of cells. In the present study, we have identified an hsp90-related gene (Djhsp90) encoding a cytosolic form of HSP90 that is primarily expressed in gastrodermis of the planarian Dugesia japonica. Djhsp90 becomes significantly induced after traumatic amputation or other stress stimuli, such as exposure to X-ray or ultraviolet radiations, heat shock, or prolonged starvation. When Djhsp90 is silenced by ribonucleic acid interference (RNAi), planarians dramatically decrease in size, becoming unable to eat, and die in a few weeks. Our results indicate that this gene plays an essential cytoprotective role in the gastrodermis of planarians and suggest that this chaperone can be involved in autophagic processes that are activated by this tissue. PMID:20706815

  4. Smed-betacatenin-1 is required for anteroposterior blastema polarity in planarian regeneration.

    PubMed

    Petersen, Christian P; Reddien, Peter W

    2008-01-18

    Planarian flatworms can regenerate heads at anterior-facing wounds and tails at posterior-facing wounds throughout the body. How this regeneration polarity is specified has been a classic problem for more than a century. We identified a planarian gene, Smed-betacatenin-1, that controls regeneration polarity. Posterior-facing blastemas regenerate a head instead of a tail in Smed-betacatenin-1(RNAi) animals. Smed-betacatenin-1 is required after wounding and at any posterior-facing wound for polarity. Additionally, intact Smed-betacatenin-1(RNAi) animals display anteriorization during tissue turnover. Five Wnt genes and a secreted Frizzled-related Wnt antagonist-like gene are expressed in domains along the anteroposterior axis that reset to new positions during regeneration, which suggests that Wnts control polarity through Smed-betacatenin-1. Our data suggest that beta-catenin specifies the posterior character of the anteroposterior axis throughout the Bilateria and specifies regeneration polarity in planarians. PMID:18063755

  5. Egr-5 is a post-mitotic regulator of planarian epidermal differentiation.

    PubMed

    Tu, Kimberly C; Cheng, Li-Chun; T K Vu, Hanh; Lange, Jeffrey J; McKinney, Sean A; Seidel, Chris W; Sánchez Alvarado, Alejandro

    2015-01-01

    Neoblasts are an abundant, heterogeneous population of adult stem cells (ASCs) that facilitate the maintenance of planarian tissues and organs, providing a powerful system to study ASC self-renewal and differentiation dynamics. It is unknown how the collective output of neoblasts transit through differentiation pathways to produce specific cell types. The planarian epidermis is a simple tissue that undergoes rapid turnover. We found that as epidermal progeny differentiate, they progress through multiple spatiotemporal transition states with distinct gene expression profiles. We also identified a conserved early growth response family transcription factor, egr-5, that is essential for epidermal differentiation. Disruption of epidermal integrity by egr-5 RNAi triggers a global stress response that induces the proliferation of neoblasts and the concomitant expansion of not only epidermal, but also multiple progenitor cell populations. Our results further establish the planarian epidermis as a novel paradigm to uncover the molecular mechanisms regulating ASC specification in vivo. PMID:26457503

  6. A functional genomic screen in planarians identifies novel regulators of germ cell development

    PubMed Central

    Wang, Yuying; Stary, Joel M.; Wilhelm, James E.; Newmark, Phillip A.

    2010-01-01

    Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms. PMID:20844018

  7. The molecular logic for planarian regeneration along the anterior-posterior axis.

    PubMed

    Umesono, Yoshihiko; Tasaki, Junichi; Nishimura, Yui; Hrouda, Martina; Kawaguchi, Eri; Yazawa, Shigenobu; Nishimura, Osamu; Hosoda, Kazutaka; Inoue, Takeshi; Agata, Kiyokazu

    2013-08-01

    The planarian Dugesia japonica can regenerate a complete individual from a head, trunk or tail fragment via activation of somatic pluripotent stem cells. About a century ago, Thomas Hunt Morgan attempted to explain the extraordinary regenerative ability of planarians by positing two opposing morphogenetic gradients of formative "head stuff" and "tail stuff" along the anterior-posterior axis. However, Morgan's hypothesis remains open to debate. Here we show that extracellular signal-related kinase (ERK) and Wnt/β-catenin signalling pathways establish a solid framework for planarian regeneration. Our data suggest that ERK signalling forms a spatial gradient in the anterior region during regeneration. The fibroblast growth factor receptor-like gene nou-darake (which serves as an output of ERK signalling in the differentiating head) and posteriorly biased β-catenin activity negatively regulate ERK signalling along the anterior-posterior axis in distinct manners, and thereby posteriorize regenerating tissues outside the head region to reconstruct a complete head-to-tail axis. On the basis of this knowledge about D. japonica, we proposed that β-catenin signalling is responsible for the lack of head-regenerative ability of tail fragments in the planarian Phagocata kawakatsui, and our confirmation thereof supports the notion that posterior β-catenin signalling negatively modulates the ERK signalling involved in anteriorization across planarian species. These findings suggest that ERK signalling has a pivotal role in triggering globally dynamic differentiation of stem cells in a head-to-tail sequence through a default program that promotes head tissue specification in the absence of posteriorizing signals. Thus, we have confirmed the broad outline of Morgan's hypothesis, and refined it on the basis of our proposed default property of planarian stem cells. PMID:23883928

  8. Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hot spot: a statistical phylogeographic study using a low-dispersal organism

    PubMed Central

    Álvarez-Presas, M; Sánchez-Gracia, A; Carbayo, F; Rozas, J; Riutort, M

    2014-01-01

    The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world's richest biodiversity hot spots, is severely damaged by human activities. To formulate an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Analysing multi-locus DNA sequence variation under the Approximate Bayesian Computation framework, we evaluated two scenarios proposed to explain the diversity of Southern Atlantic Forest (SAF) region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; nevertheless, some populations might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, whereas Pleistocene climate changes had a minor influence in generating present-day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropriate conservation policies. PMID:24549112

  9. Evidence of Nicotine-Induced, Curare-Insensitive, Behavior in Planarians.

    PubMed

    Pagán, Oné R; Montgomery, Erica; Deats, Sean; Bach, Daniel; Baker, Debra

    2015-10-01

    Planarians are rapidly developing into very useful research subjects in pharmacology and neuroscience research. Here we report that curare, a cholinergic nicotinic receptor antagonist, alleviates the nicotine-induced planarian seizure-like movements (pSLM) by up to 50 % at equimolar concentrations of nicotine and curare (1 mM), while curare alone does not induce significant pSLMs. The simplest interpretation of our data is that there are nicotine induced behaviors insensitive to curare in our experimental organism. To the best of our knowledge, this is the first report on curare-insensitive, nicotine-induced effects in any organism. PMID:25614180

  10. Patterns of occurrence of the platyhelminth parasites of the wild bullseye puffer (Sphoeroides annulatus) off Sinaloa, Mexico.

    PubMed

    Fajer-Avila, Emma Josefina; Roque, Ana; Aguilar, Gabriela; Duncan, Neil

    2004-04-01

    This study provides basic information on the occurrence of platyhelminths in the wild bullseye puffer (Sphoeroides annulatus) from Sinaloa, Mexico. Specimens of pufferfish were collected from 2 localities: Teacapan (n = 161) and Mazatlan (n = 66). Six species of platyhelminths were recorded: 2 monogeneans (Diclidophoridae: Heterobothrium ecuadori and Capsalidae: Neobenedenia melleni) and 4 digeneans (Apocreadiidae: Homalometron longisinosum, Lepocreadiidae: Bianium plicitum, Gorgoridae: Phyllodristomum mirandai, and Fellodistomidae: Lintonium vibex). This is the first record of the platyhelminth L. vibex in S. annulatus in the Mexican Pacific. Bianium plicitum was the most abundant species, and H. ecuadori was the most prevalent species. The fish from Teacapan had the higher prevalence of platyhelminths. Teacapan had higher specific richness index, whereas Mazatlan had a higher dominance, 3.098 (Teacapan = 2.38). A relative risk analysis showed that B. plicitum was more likely to be present on fish in water within the temperature range of 21-25 C and from Teacapan compared with fish from the warmer water (26-30 C) or from Mazatlan. Heterobothrium ecuadori was more likely to be present at water temperatures of 23-24.5 C on fish from Teacapan and when other ectoparasites were present. Neobenedenia melleni also was more likely to be present when other parasites were present. PMID:15165072

  11. Staining of Platyhelminthes by herbal dyes: An eco-friendly technique for the taxonomist

    PubMed Central

    Kumar, Niranjan; Mehul, Jadav; Das, Bhupamani; Solanki, J. B.

    2015-01-01

    Aim: An environment compatible technique to stain Platyhelminthes, Fasciola gigantica, Gastrothylax crumenifer, Taenia solium, and Moniezia expansa using aqueous and alcoholic extract of sugar beet (Beta vulgaris), China rose (Hibiscus rosa-sinensis), and red rose (Rosa hybrida) were described to minimized the deleterious effects of the synthetic dyes. Materials and Methods: Aqueous/ethanolic extracts of roses were extracted from the flowers while red beet was extracted from the roots. Results: Stained helminthes acquired a comparable level of pigmentation with the distinction of their internal structure in these natural dyes. The flukes (liver and rumen) internal structure, oral and ventral/posterior sucker, cirrus sac, gravid uterus, testes, ovary, and vitallaria were appeared pink color in aqueous and alcoholic extract of either China or red rose and yellow to brown color in sugar beet stain. The interior of the proglottid of T. solium and M. expansa took yellow to brown color with good contrast in sugar beet stain and of pink to pink-red in China and red rose stain. Conclusion: The extract of roses (red rose followed by China rose) followed by red beet possess the potential to replace the conventional stains in the taxonomic study of Platyhelminthes parasites. PMID:27047037

  12. Nuclear genomic signals of the ‘microturbellarian’ roots of platyhelminth evolutionary innovation

    PubMed Central

    Laumer, Christopher E; Hejnol, Andreas; Giribet, Gonzalo

    2015-01-01

    Flatworms number among the most diverse invertebrate phyla and represent the most biomedically significant branch of the major bilaterian clade Spiralia, but to date, deep evolutionary relationships within this group have been studied using only a single locus (the rRNA operon), leaving the origins of many key clades unclear. In this study, using a survey of genomes and transcriptomes representing all free-living flatworm orders, we provide resolution of platyhelminth interrelationships based on hundreds of nuclear protein-coding genes, exploring phylogenetic signal through concatenation as well as recently developed consensus approaches. These analyses robustly support a modern hypothesis of flatworm phylogeny, one which emphasizes the primacy of the often-overlooked ‘microturbellarian’ groups in understanding the major evolutionary transitions within Platyhelminthes: perhaps most notably, we propose a novel scenario for the interrelationships between free-living and vertebrate-parasitic flatworms, providing new opportunities to shed light on the origins and biological consequences of parasitism in these iconic invertebrates. DOI: http://dx.doi.org/10.7554/eLife.05503.001 PMID:25764302

  13. Making Heads or Tails: Planarian Stem Cells in the Classroom†

    PubMed Central

    Srougi, Melissa C.; Thomas-Swanik, Jackie; Chan, John D.; Marchant, Jonathan S.; Carson, Susan

    2014-01-01

    Stem cells hold great promise in the treatment of diseases ranging from cancer to dementia. However, as rapidly as the field of stem cell biology has emerged, heated political debate has followed, scrutinizing the ethical implications of stem cell use. It is therefore imperative to promote scientific literacy by educating students about stem cell biology. Yet, there is a definite lack of material to engage students in this subject at the basic science level. Therefore, we have developed and implemented a hands-on introductory laboratory module that introduces students to stem cell biology and can be easily incorporated into existing curricula. Students learn about stem cell biology using an in vivo planarian model system in which they down-regulate two genes important in stem cell differentiation using RNA interference and then observe the regenerative phenotype. The module was piloted at the high school, community college, and university levels. Here, we report that introductory biology students enrolled at a community college were able to demonstrate gains in learning after completion of a one-hour lecture and four 45-minute laboratory sessions over the course of three weeks. These gains in learning outcomes were objectively evaluated both before and after its execution using a student quiz and experimental results. Furthermore, students’ self-assessments revealed increases in perceived knowledge as well as a general interest in stem cells. Therefore, these data suggest that this module is a simple, useful way to engage and to teach students about stem cell biology. PMID:24839511

  14. Bioelectrical regulation of cell cycle and the planarian model system.

    PubMed

    Barghouth, Paul G; Thiruvalluvan, Manish; Oviedo, Néstor J

    2015-10-01

    Cell cycle regulation through the manipulation of endogenous membrane potentials offers tremendous opportunities to control cellular processes during tissue repair and cancer formation. However, the molecular mechanisms by which biophysical signals modulate the cell cycle remain underappreciated and poorly understood. Cells in complex organisms generate and maintain a constant voltage gradient across the plasma membrane known as the transmembrane potential. This potential, generated through the combined efforts of various ion transporters, pumps and channels, is known to drive a wide range of cellular processes such as cellular proliferation, migration and tissue regeneration while its deregulation can lead to tumorigenesis. These cellular regulatory events, coordinated by ionic flow, correspond to a new and exciting field termed molecular bioelectricity. We aim to present a brief discussion on the biophysical machinery involving membrane potential and the mechanisms mediating cell cycle progression and cancer transformation. Furthermore, we present the planarian Schmidtea mediterranea as a tractable model system for understanding principles behind molecular bioelectricity at both the cellular and organismal level. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. PMID:25749155

  15. Discovery of Platyhelminth-Specific α/β-Integrin Families and Evidence for Their Role in Reproduction in Schistosoma mansoni

    PubMed Central

    Beckmann, Svenja; Quack, Thomas; Dissous, Colette; Cailliau, Katia; Lang, Gabriele; Grevelding, Christoph G.

    2012-01-01

    In all metazoa, the response of cells to molecular stimuli from their environment represents a fundamental principle of regulatory processes controlling cell growth and differentiation. Among the membrane-linked receptors mediating extracellular communication processes are integrin receptors. Besides managing adhesion to the extracellular matrix or to other cells, they arrange information flow into the cells by activating intracellular signaling pathways often acting synergistically through cooperation with growth factor receptors. Although a wealth of information exists on integrins in different model organisms, there is a big gap of knowledge for platyhelminths. Here we report on the in silico detection and reconstruction of α and β integrins from free-living and parasitic platyhelminths, which according to structural and phylogenetic analyses form specific clades separate from each other and from further metazoan integrins. As representative orthologs of parasitic platyhelminths we have cloned one beta-integrin (Smβ-Int1) and four alpha-integrins (Smα-Int1 - Smα-Int4) from Schistosoma mansoni; they were characterized by molecular and biochemical analyses. Evidence is provided that Smβ-Int1 interacts and co-localizes in the reproductive organs with known schistosome cellular tyrosine kinases (CTKs), of which the Syk kinase SmTK4 appeared to be the strongest interaction partner as shown by yeast two-hybrid analyses and coimmunoprecipitation experiments. By a novel RNAi approach with adult schistosomes in vitro we demonstrate for the first time multinucleated oocytes in treated females, indicating a decisive role Smβ-Int1 during oogenesis as phenotypically analyzed by confocal laser scanning microscopy (CLSM). Our findings provide a first comprehensive overview about platyhelminth integrins, of which the parasite group exhibits unique features allowing a clear distinction from the free-living groups. Furthermore, we shed first lights on the functions of

  16. Forkhead containing transcription factor Albino controls tetrapyrrole-based body pigmentation in planarian

    PubMed Central

    Wang, Chen; Han, Xiao-Shuai; Li, Fang-Fang; Huang, Shuang; Qin, Yong-Wen; Zhao, Xian-Xian; Jing, Qing

    2016-01-01

    Pigmentation processes occur from invertebrates to mammals. Owing to the complexity of the pigmentary system, in vivo animal models for pigmentation study are limited. Planarians are capable of regenerating any missing part including the dark-brown pigments, providing a promising model for pigmentation study. However, the molecular mechanism of planarian body pigmentation is poorly understood. We found in an RNA interference screen that a forkhead containing transcription factor, Albino, was required for pigmentation without affecting survival or other regeneration processes. In addition, the body color recovered after termination of Albino double stranded RNA feeding owing to the robust stem cell system. Further expression analysis revealed a spatial and temporal correlation between Albino and pigmentation process. Gene expression arrays revealed that the expression of three tetrapyrrole biosynthesis enzymes, ALAD, ALAS and PBGD, was impaired upon Albino RNA interference. RNA interference of PBGD led to a similar albinism phenotype caused by Albino RNA interference. Moreover, PBGD was specifically expressed in pigment cells and can serve as a pigment cell molecular marker. Our results revealed that Albino controls planarian body color pigmentation dominantly via regulating tetrapyrrole biogenesis. These results identified Albino as the key regulator of the tetrapyrrole-based planarian body pigmentation, suggesting a role of Albino during stem cell-pigment cell fate decision and provided new insights into porphyria pathogenesis. PMID:27551436

  17. Expression of secreted Wnt pathway components reveals unexpected complexity of the planarian amputation response.

    PubMed

    Gurley, Kyle A; Elliott, Sarah A; Simakov, Oleg; Schmidt, Heiko A; Holstein, Thomas W; Sánchez Alvarado, Alejandro

    2010-11-01

    Regeneration is widespread throughout the animal kingdom, but our molecular understanding of this process in adult animals remains poorly understood. Wnt/β-catenin signaling plays crucial roles throughout animal life from early development to adulthood. In intact and regenerating planarians, the regulation of Wnt/β-catenin signaling functions to maintain and specify anterior/posterior (A/P) identity. Here, we explore the expression kinetics and RNAi phenotypes for secreted members of the Wnt signaling pathway in the planarian Schmidtea mediterranea. Smed-wnt and sFRP expression during regeneration is surprisingly dynamic and reveals fundamental aspects of planarian biology that have been previously unappreciated. We show that after amputation, a wounding response precedes rapid re-organization of the A/P axis. Furthermore, cells throughout the body plan can mount this response and reassess their new A/P location in the complete absence of stem cells. While initial stages of the amputation response are stem cell independent, tissue remodeling and the integration of a new A/P address with anatomy are stem cell dependent. We also show that WNT5 functions in a reciprocal manner with SLIT to pattern the planarian mediolateral axis, while WNT11-2 patterns the posterior midline. Moreover, we perform an extensive phylogenetic analysis on the Smed-wnt genes using a method that combines and integrates both sequence and structural alignments, enabling us to place all nine genes into Wnt subfamilies for the first time. PMID:20707997

  18. Group planarian sudden mortality: Is the threshold around global geomagnetic activity ≥K6?

    PubMed Central

    Murugan, Nirosha J; Karbowski, Lukasz M; Mekers, William Ft; Persinger, Michael A

    2015-01-01

    Sudden deaths in groups of animals have been observed by field and laboratory biologists. We have measured mortalities in large group-housed planarian during the infrequent periods of very intense geomagnetic activity. In 13 separate episodes over the last 5 y we have observed the sudden death in our laboratory of hundreds of planarian if their density was about 1 worm per cc and the global geomagnetic activity was K≥6 the day before or the day of the observation of the mortality. Such mortality never occurred in other conditions or days. Both estimates of the "magnetic moment" of a planarian in magnetic fields above this threshold of sustained magnetic flux density as well as the magnetic energy within the planarian volume predict values that could affect phenomenon associated with the total numbers of pH-dependent charges within each worm. These conditions could affect the Levin-Burr bioelectrical signals and networks that affect patterning information and sustainability in whole living systems. The establishment of a central reservoir for the report of these transient events might allow Life Scientists to more fully appreciate the impact of these pervasive global stimuli upon dense groups of animals. PMID:27066174

  19. Memory and obesity affect the population dynamics of asexual freshwater planarians

    NASA Astrophysics Data System (ADS)

    Dunkel, Jörn; Talbot, Jared; Schötz, Eva-Maria

    2011-04-01

    Asexual reproduction in multicellular organisms is a complex biophysical process that is not yet well understood quantitatively. Here, we report a detailed population study for the asexual freshwater planarian Schmidtea mediterranea, which can reproduce via transverse fission due to a large stem cell contingent. Our long-term observations of isolated non-interacting planarian populations reveal that the characteristic fission waiting time distributions for head and tail fragments differ significantly from each other. The stochastic fission dynamics of tail fragments exhibits non-negligible memory effects, implying that an accurate mathematical description of future data should be based on non-Markovian tree models. By comparing the effective growth of non-interacting planarian populations with those of self-interacting populations, we are able to quantify the influence of interactions between flatworms and physical conditions on the population growth. A surprising result is the non-monotonic relationship between effective population growth rate and nutrient supply: planarians exhibit a tendency to become 'obese' if the feeding frequency exceeds a critical level, resulting in a decreased reproduction activity. This suggests that these flatworms, which possess many genes homologous to those of humans, could become a new model system for studying dietary effects on reproduction and regeneration in multicellular organisms.

  20. Forkhead containing transcription factor Albino controls tetrapyrrole-based body pigmentation in planarian.

    PubMed

    Wang, Chen; Han, Xiao-Shuai; Li, Fang-Fang; Huang, Shuang; Qin, Yong-Wen; Zhao, Xian-Xian; Jing, Qing

    2016-01-01

    Pigmentation processes occur from invertebrates to mammals. Owing to the complexity of the pigmentary system, in vivo animal models for pigmentation study are limited. Planarians are capable of regenerating any missing part including the dark-brown pigments, providing a promising model for pigmentation study. However, the molecular mechanism of planarian body pigmentation is poorly understood. We found in an RNA interference screen that a forkhead containing transcription factor, Albino, was required for pigmentation without affecting survival or other regeneration processes. In addition, the body color recovered after termination of Albino double stranded RNA feeding owing to the robust stem cell system. Further expression analysis revealed a spatial and temporal correlation between Albino and pigmentation process. Gene expression arrays revealed that the expression of three tetrapyrrole biosynthesis enzymes, ALAD, ALAS and PBGD, was impaired upon Albino RNA interference. RNA interference of PBGD led to a similar albinism phenotype caused by Albino RNA interference. Moreover, PBGD was specifically expressed in pigment cells and can serve as a pigment cell molecular marker. Our results revealed that Albino controls planarian body color pigmentation dominantly via regulating tetrapyrrole biogenesis. These results identified Albino as the key regulator of the tetrapyrrole-based planarian body pigmentation, suggesting a role of Albino during stem cell-pigment cell fate decision and provided new insights into porphyria pathogenesis. PMID:27551436

  1. Unusually Large Number of Mutations in Asexually Reproducing Clonal Planarian Dugesia japonica

    PubMed Central

    Nishimura, Osamu; Hosoda, Kazutaka; Kawaguchi, Eri; Yazawa, Shigenobu; Hayashi, Tetsutaro; Inoue, Takeshi; Umesono, Yoshihiko; Agata, Kiyokazu

    2015-01-01

    We established a laboratory clonal strain of freshwater planarian (Dugesia japonica) that was derived from a single individual and that continued to undergo autotomous asexual reproduction for more than 20 years, and we performed large-scale genome sequencing and transcriptome analysis on it. Despite the fact that a completely clonal strain of the planarian was used, an unusually large number of mutations were detected. To enable quantitative genetic analysis of such a unique organism, we developed a new model called the Reference Gene Model, and used it to conduct large-scale transcriptome analysis. The results revealed large numbers of mutations not only outside but also inside gene-coding regions. Non-synonymous SNPs were detected in 74% of the genes for which valid ORFs were predicted. Interestingly, the high-mutation genes, such as metabolism- and defense-related genes, were correlated with genes that were previously identified as diverse genes among different planarian species. Although a large number of amino acid substitutions were apparently accumulated during asexual reproduction over this long period of time, the planarian maintained normal body-shape, behaviors, and physiological functions. The results of the present study reveal a unique aspect of asexual reproduction. PMID:26588467

  2. Unusually Large Number of Mutations in Asexually Reproducing Clonal Planarian Dugesia japonica.

    PubMed

    Nishimura, Osamu; Hosoda, Kazutaka; Kawaguchi, Eri; Yazawa, Shigenobu; Hayashi, Tetsutaro; Inoue, Takeshi; Umesono, Yoshihiko; Agata, Kiyokazu

    2015-01-01

    We established a laboratory clonal strain of freshwater planarian (Dugesia japonica) that was derived from a single individual and that continued to undergo autotomous asexual reproduction for more than 20 years, and we performed large-scale genome sequencing and transcriptome analysis on it. Despite the fact that a completely clonal strain of the planarian was used, an unusually large number of mutations were detected. To enable quantitative genetic analysis of such a unique organism, we developed a new model called the Reference Gene Model, and used it to conduct large-scale transcriptome analysis. The results revealed large numbers of mutations not only outside but also inside gene-coding regions. Non-synonymous SNPs were detected in 74% of the genes for which valid ORFs were predicted. Interestingly, the high-mutation genes, such as metabolism- and defense-related genes, were correlated with genes that were previously identified as diverse genes among different planarian species. Although a large number of amino acid substitutions were apparently accumulated during asexual reproduction over this long period of time, the planarian maintained normal body-shape, behaviors, and physiological functions. The results of the present study reveal a unique aspect of asexual reproduction. PMID:26588467

  3. DjPiwiB: A Rich Nuclear Inheritance for Descendants of Planarian Stem Cells.

    PubMed

    Tharp, Marla E; Bortvin, Alex

    2016-05-01

    Stem cell differentiation involves a delicate balance of gene expression and transposon repression. In this issue of Developmental Cell, Shibata et al. (2016) show that a PIWI protein expressed in planarian stem cells is inherited by their differentiating descendants to ensure regenerative capacity of the flatworm via transposon silencing. PMID:27165550

  4. PRMT5 and the role of symmetrical dimethylarginine in chromatoid bodies of planarian stem cells

    PubMed Central

    Rouhana, Labib; Vieira, Ana P.; Roberts-Galbraith, Rachel H.; Newmark, Phillip A.

    2012-01-01

    Planarian flatworms contain a population of adult stem cells (neoblasts) that proliferate and generate cells of all tissues during growth, regeneration and tissue homeostasis. A characteristic feature of neoblasts is the presence of chromatoid bodies, large cytoplasmic ribonucleoprotein (RNP) granules morphologically similar to structures present in the germline of many organisms. This study aims to reveal the function, and identify additional components, of planarian chromatoid bodies. We uncover the presence of symmetrical dimethylarginine (sDMA) on chromatoid body components and identify the ortholog of protein arginine methyltransferase PRMT5 as the enzyme responsible for sDMA modification in these proteins. RNA interference-mediated depletion of planarian PRMT5 results in defects in homeostasis and regeneration, reduced animal size, reduced number of neoblasts, fewer chromatoid bodies and increased levels of transposon and repetitive-element transcripts. Our results suggest that PIWI family member SMEDWI-3 is one sDMA-containing chromatoid body protein for which methylation depends on PRMT5. Additionally, we discover an RNA localized to chromatoid bodies, germinal histone H4. Our results reveal new components of chromatoid bodies and their function in planarian stem cells, and also support emerging studies indicative of sDMA function in stabilization of RNP granules and the Piwi-interacting RNA pathway. PMID:22318224

  5. Molecular markers to characterize the hermaphroditic reproductive system of the planarian Schmidtea mediterranea

    PubMed Central

    2011-01-01

    Background The freshwater planarian Schmidtea mediterranea exhibits two distinct reproductive modes. Individuals of the sexual strain are cross-fertilizing hermaphrodites with reproductive organs that develop post-embryonically. By contrast, individuals of the asexual strain reproduce exclusively by transverse fission and fail to develop reproductive organs. These different reproductive strains are associated with distinct karyotypes, making S. mediterranea a useful model for studying germline development and sexual differentiation. Results To identify genes expressed differentially between these strains, we performed microarray analyses and identified >800 genes that were upregulated in the sexual planarian. From these, we characterized 24 genes by fluorescent in situ hybridization (FISH), revealing their expression in male germ cells or accessory reproductive organs. To identify additional markers of the planarian reproductive system, we also used immuno- and fluorescent lectin staining, identifying several antibodies and lectins that labeled structures associated with reproductive organs. Conclusions Collectively, these cell-type specific markers will enable future efforts to characterize genes that are important for reproductive development in the planarian. PMID:22074376

  6. Expression of secreted Wnt pathway components reveals unexpected complexity of the planarian amputation response

    PubMed Central

    Gurley, Kyle A.; Elliott, Sarah A.; Simakov, Oleg; Schmidt, Heiko A.; Holstein, Thomas W.; Sánchez Alvarado, Alejandro

    2010-01-01

    Regeneration is widespread throughout the animal kingdom, but our molecular understanding of this process in adult animals remains poorly understood. Wnt/β-catenin signaling plays crucial roles throughout animal life from early development to adulthood. In intact and regenerating planarians, the regulation of Wnt/β-catenin signaling functions to maintain and specify anterior/posterior (A/P) identity. Here, we explore the expression kinetics and RNAi phenotypes for secreted members of the Wnt signaling pathway in the planarian Schmidtea mediterranea. Smed-wnt and sFRP expression during regeneration is surprisingly dynamic and reveals fundamental aspects of planarian biology that have been previously unappreciated. We show that after amputation, a wounding response precedes rapid reorganization of the A/P axis. Furthermore, cells throughout the body plan can mount this response and reassess their new A/P location in the complete absence of stem cells. While initial stages of the amputation response are stem cell independent, tissue remodeling and the integration of new A/P address with anatomy are stem cell dependent. We also show that WNT5 functions in a reciprocal manner with SLIT to pattern the planarian mediolateral axis, while WNT11-2 patterns the posterior midline. Moreover, we perform an extensive phylogenetic analysis on the Smed-wnt genes using a method that combines and integrates both sequence and structural alignments, enabling us to place all nine genes into Wnt subfamilies for the first time. PMID:20707997

  7. Epigenetic regulation of planarian stem cells by the SET1/MLL family of histone methyltransferases

    PubMed Central

    Hubert, Amy; Henderson, Jordana M.; Ross, Kelly G.; Cowles, Martis W.; Torres, Jessica; Zayas, Ricardo M.

    2013-01-01

    Chromatin regulation is a fundamental mechanism underlying stem cell pluripotency, differentiation, and the establishment of cell type-specific gene expression profiles. To examine the role of chromatin regulation in stem cells in vivo, we study regeneration in the freshwater planarian Schmidtea mediterranea. These animals possess a high concentration of pluripotent stem cells, which are capable of restoring any damaged or lost tissues after injury or amputation. Here, we identify the S. mediterranea homologs of the SET1/MLL family of histone methyltransferases and COMPASS and COMPASS-like complex proteins and investigate their role in stem cell function during regeneration. We identified six S. mediterranea homologs of the SET1/MLL family (set1, mll1/2, trr-1, trr-2, mll5–1 and mll5–2), characterized their patterns of expression in the animal, and examined their function by RNAi. All members of this family are expressed in the stem cell population and differentiated tissues. We show that set1, mll1/2, trr-1, and mll5–2 are required for regeneration and that set1, trr-1 and mll5–2 play roles in the regulation of mitosis. Most notably, knockdown of the planarian set1 homolog leads to stem cell depletion. A subset of planarian homologs of COMPASS and COMPASS-like complex proteins are also expressed in stem cells and implicated in regeneration, but the knockdown phenotypes suggest that some complex members also function in other aspects of planarian biology. This work characterizes the function of the SET1/MLL family in the context of planarian regeneration and provides insight into the role of these enzymes in adult stem cell regulation in vivo. PMID:23235145

  8. Inhibitory Smads and bone morphogenetic protein (BMP) modulate anterior photoreceptor cell number during planarian eye regeneration.

    PubMed

    González-Sastre, Alejandro; Molina, Ma Dolores; Saló, Emili

    2012-01-01

    Planarians represent an excellent model to study the processes of body axis and organ re-specification during regeneration. Previous studies have revealed a conserved role for the bone morphogenetic protein (BMP) pathway and its intracellular mediators Smad1/5/8 and Smad4 in planarian dorsoventral (DV) axis re-establishment. In an attempt to gain further insight into the role of this signalling pathway in planarians, we have isolated and functionally characte-rized the inhibitory Smads (I-Smads) in Schmidtea mediterranea. Two I-Smad homologues have been identified: Smed-smad6/7-1 and Smed-smad6/7-2. Expression of smad6/7-1 was detected in the parenchyma, while smad6/7-2 was found to be ex-pressed in the central nervous system and the eyes. Neither single smad6/7-1 and smad6/7-2 nor double smad6/7-1,-2 silencing gave rise to any apparent disruption of the DV axis. However, both regenerating and intact smad6/7-2 (RNAi) planarians showed defects in eye morphogenesis and displayed small, rounded eyes that lacked the anterior subpopulation of photoreceptor cells. The number of pigment cells was also reduced in these animals at later stages of regeneration. In contrast, after low doses of Smed-bmp(RNAi), planarians regenerated larger eyes in which the anterior subpopulation of photoreceptor cells was expanded. Our results suggest that Smed-smad6/7-2 and Smed-bmp control the re-specification and maintenance of anterior photoreceptor cell number in S. mediterranea. PMID:22451003

  9. Protein expression profiling in head fragments during planarian regeneration after amputation.

    PubMed

    Chen, Xiaoguang; Xu, Cunshuan

    2015-04-01

    Following amputation, a planarian tail fragment can regrow into a complete organism including a well-organized brain within about 2-3 weeks, thus restoring the structure and function to presurgical levels. Despite the enormous potential of these animals for regenerative medicine, our understanding of the exact mechanism of planarian regeneration is incomplete. To better understand the molecular nature of planarian head regeneration, we applied two-dimensional electrophoresis (2-DE)/matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)/time-of-flight mass spectrometry (TOF MS) technique to analyze the dynamic proteomic expression profiles over the course of 6 to 168 h post-decapitation. This approach identified a total of 141 differentially expressed proteins, 47 of which exhibited exceptionally high fold changes (≥3-fold change). Of these, Rx protein, an important regulator of head and brain development, was considered to be closely related to planarian head regeneration because of its exceptional high expression almost throughout the time course of regeneration process. Functional annotation analysis classified the 141 proteins into eight categories: (1) signaling, (2) Ca(2+) binding and translocation, (3) transcription and translation, (4) cytoskeleton, (5) metabolism, (6) cell protection, (7) tissue differentiation, and (8) cell cycle. Signaling pathway analysis indicated that Wnt1/Ca(2+) signaling pathway was activated during head regeneration. Integrating the analyses of proteome expression profiling, functional annotation, and signaling pathway, amputation-induced head reformation requires some mechanisms to promote cell proliferation and differentiation, including differential regulation of proapoptotic and antiapoptotic proteins, and the regulation of proliferation and differentiation-related proteins. Importantly, Wnt1/Ca(2+) signaling pathway upregulates Rx expression, finally facilitating the differentiation of neoblasts into various

  10. Survival, mobility, and membrane-bound enzyme activities of freshwater planarian, Dugesia japonica, exposed to synthetic and natural surfactants.

    PubMed

    Li, Mei-Hui

    2012-04-01

    Surfactants are a major class of emerging pollutants widely used in large quantities in everyday life and commonly found in surface waters worldwide. Freshwater planarian was selected to examine the effects of different surfactants by measuring mortality, mobility, and membrane-bound enzyme activities. Among the 10 surfactants tested, the acute toxicities of betaine and polyethylene glycol (PEG-200) to planarians were relatively low, with a median lethal concentration (LC50) greater than 10,000 mg/L. The toxicity to planarians of the other eight surfactants based on 48-h LC50 could be arranged in the descending order of cetylpyridinum chloride (CPC) > 4-tert-octylphenol (4-tert-OP) > ammonium lauryl sulfate > benzalkonium chloride > saponin > sodium lauroylsarcosinate > dioctyl sulfosuccinate > dodecyl trimethyl ammonium bromide (DTAB). Both CPC and 4-tert-OP were very toxic to planarians, with 48-h LC50 values <1 mg/L. The median effective concentrations (EC50s) of planarian mobility were in the 0.1 to 50 mg/L range and were in the same range as the 24-h LC50 of planarians exposed to different surfactants, except for DTAB. In addition, significant inhibition of cholinesterase activity activities was found in planarians exposed to 4-tert-OP at 2.5 and 5 mg/L and to saponin at 10 mg/L after 2-h treatments. This result suggests that planarian mobility responses can be used as an alternative indicator for acute toxicity of surfactants after a very short exposure period. PMID:22278771

  11. Development of in vivo biotransformation enzyme assays for ecotoxicity screening: In vivo measurement of phases I and II enzyme activities in freshwater planarians.

    PubMed

    Li, Mei-Hui

    2016-08-01

    The development of a high-throughput tool is required for screening of environmental pollutants and assessing their impacts on aquatic animals. Freshwater planarians can be used in rapid and sensitive toxicity bioassays. Planarians are known for their remarkable regeneration ability but much less known for their metabolic and xenobiotic biotransformation abilities. In this study, the activities of different phase I and II enzymes were determined in vivo by directly measuring fluorescent enzyme substrate disappearance or fluorescent enzyme metabolite production in planarian culture media. For phase I enzyme activity, O-deethylation activities with alkoxyresorufin could not be detected in planarian culture media. By contrast, O-deethylation activities with alkoxycoumarin were detected in planarian culture media. Increases in 7-ethoxycoumarin O-deethylase (ECOD) activities was only observed in planarians exposed to 1μM, but not 10μM, β-naphthoflavone for 24h. ECOD activity was inhibited in planarians exposed to 10 and 100μM rifampicin or carbamazepine for 24h. For phase II enzyme activity, DT-diaphorase, arylsulfatases, uridine 5'-diphospho (UDP)-glucuronosyltransferase or catechol-O-methyltransferase activity was determined in culture media containing planarians. The results of this study indicate that freshwater planarians are a promising model organism to monitor exposure to environmental pollutants or assess their impacts through the in vivo measurement of phase I and II enzyme activities. PMID:27062342

  12. Preference for different prey allows the coexistence of several land planarians in areas of the Atlantic Forest.

    PubMed

    Boll, Piter Kehoma; Leal-Zanchet, Ana Maria

    2016-06-01

    Land planarians are recognized as important predators, yet studies on their feeding habits are usually restricted to invasive species. Thus, it is difficult to determine the real ecological role of this group in ecosystems and how their communities are structured. In the present study, we analyzed the diet of six co-occurring Neotropical land planarians and their success in capturing prey, based on experiments in the laboratory, in order to determine how they share resources in the same environment. We also calculated indices of food niche breadth and food niche overlap for land planarians for the first time. The diet of Luteostriata abundans comprises only woodlice and the diets of Obama ficki and Obama ladislavii are composed only of gastropods, while Paraba multicolor and Obama anthropophila feed on both gastropods and other land planarians. An invasive species recently found in Western Europe, Obama nungara, showed the highest food niche breadth, feeding on gastropods, earthworms and planarians. We found the highest niche overlap between O. anthropophila and P. multicolor. The results suggest that land planarians are frequent predators of woodlice and land gastropods in the Neotropical ecozone and thus are important for the maintenance of native ecosystems and for the control of invasive species. The coexistence of several species in the same habitat is possible due to the use of different species as main prey, which reduces interspecific competition. PMID:27156235

  13. Knockdown of the coenzyme Q synthesis gene Smed-dlp1 affects planarian regeneration and tissue homeostasis

    PubMed Central

    Shiobara, Yumiko; Harada, Chiaki; Shiota, Takeshi; Sakamoto, Kimitoshi; Kita, Kiyoshi; Tanaka, Saeko; Tabata, Kenta; Sekie, Kiyoteru; Yamamoto, Yorihiro; Sugiyama, Tomoyasu

    2015-01-01

    The freshwater planarian is a model organism used to study tissue regeneration that occupies an important position among multicellular organisms. Planarian genomic databases have led to the identification of genes that are required for regeneration, with implications for their roles in its underlying mechanism. Coenzyme Q (CoQ) is a fundamental lipophilic molecule that is synthesized and expressed in every cell of every organism. Furthermore, CoQ levels affect development, life span, disease and aging in nematodes and mice. Because CoQ can be ingested in food, it has been used in preventive nutrition. In this study, we investigated the role of CoQ in planarian regeneration. Planarians synthesize both CoQ9 and rhodoquinone 9 (RQ9). Knockdown of Smed-dlp1, a trans-prenyltransferase gene that encodes an enzyme that synthesizes the CoQ side chain, led to a decrease in CoQ9 and RQ9 levels. However, ATP levels did not consistently decrease in these animals. Knockdown animals exhibited tissue regression and curling. The number of mitotic cells decreased in Smed-dlp1 (RNAi) animals. These results suggested a failure in physiological cell turnover and stem cell function. Accordingly, regenerating planarians died from lysis or exhibited delayed regeneration. Interestingly, the observed phenotypes were partially rescued by ingesting food supplemented with α-tocopherol. Taken together, our results suggest that oxidative stress induced by reduced CoQ9 levels affects planarian regeneration and tissue homeostasis. PMID:26516985

  14. Knockdown of the coenzyme Q synthesis gene Smed-dlp1 affects planarian regeneration and tissue homeostasis.

    PubMed

    Shiobara, Yumiko; Harada, Chiaki; Shiota, Takeshi; Sakamoto, Kimitoshi; Kita, Kiyoshi; Tanaka, Saeko; Tabata, Kenta; Sekie, Kiyoteru; Yamamoto, Yorihiro; Sugiyama, Tomoyasu

    2015-12-01

    The freshwater planarian is a model organism used to study tissue regeneration that occupies an important position among multicellular organisms. Planarian genomic databases have led to the identification of genes that are required for regeneration, with implications for their roles in its underlying mechanism. Coenzyme Q (CoQ) is a fundamental lipophilic molecule that is synthesized and expressed in every cell of every organism. Furthermore, CoQ levels affect development, life span, disease and aging in nematodes and mice. Because CoQ can be ingested in food, it has been used in preventive nutrition. In this study, we investigated the role of CoQ in planarian regeneration. Planarians synthesize both CoQ9 and rhodoquinone 9 (RQ9). Knockdown of Smed-dlp1, a trans-prenyltransferase gene that encodes an enzyme that synthesizes the CoQ side chain, led to a decrease in CoQ9 and RQ9 levels. However, ATP levels did not consistently decrease in these animals. Knockdown animals exhibited tissue regression and curling. The number of mitotic cells decreased in Smed-dlp1 (RNAi) animals. These results suggested a failure in physiological cell turnover and stem cell function. Accordingly, regenerating planarians died from lysis or exhibited delayed regeneration. Interestingly, the observed phenotypes were partially rescued by ingesting food supplemented with α-tocopherol. Taken together, our results suggest that oxidative stress induced by reduced CoQ9 levels affects planarian regeneration and tissue homeostasis. PMID:26516985

  15. [The influence of Janicki cercomer theory on the development of platyhelminthes systematics and evolution investigations].

    PubMed

    Pojmańska, Teresa

    2005-01-01

    The aim of this article was to present the development of ideas about the provenience of parasitic helminths and the phylogenetical relationships within this taxon, since the publication of the "cercomer theory" just to nowadays. The following essentials of the Janicki theory are outlined: main differences between free-living Turbellaria and parasitic platyhelminths (ciliated epithelium in Turbellaria versus unciliated surface in the others); universality of the cercomer presence in Monogenea, Digenea and Cestoda; evolutionary changes in the morphology and function of the cercomer; homology of the caudal appendices of all parasitic helminths; the subsequent evolution of parasitic platyhelminthes from the ancestor to Monogena, Digenea and Cestoda; proposition to establish a new common taxon--Cercomerophora--for these three groups. In this background the evolution of evolutionary ideas is reviewed, divided into two periods: up to the eighties of the XX century, and up to date. The first period can be characterised by the criticism of some points of the "cercomer theory" and formulation of some new hypotheses; these are those of Fuhrmann, Bychovsky, Llewellyn, Price and Malmberg, which: questioned the homology of the cercarial tail with the caudal appendices of Monogenea and Cestoda; rejected Digenea from the common group; established the common taxon--Cercomeromorpha--comprising only Monogenea and Cestoda; opposed the idea of radial evolution of three main groups of Platyhelmithes (Turbellaria, Digenea and Cercomeromorpha) to the idea of subsequent evolution presented by Janicki. The differences between these last hypotheses are also underlined, arising mainly from the different ideas on the importance of particular features as the evolutionary indicators of affinities between and within the taxons. As to the hypotheses dealing with the evolution of particular groups of parasitic platyhelminths formulated at the same period, the publications of Freeman and Jarecka

  16. New species of Gieysztoria (Platyhelminthes, Rhabdocoela) from Peruvian Amazon floodplain with description of their stylet ultrastructure.

    PubMed

    Damborenea, Cristina; Brusa, Francisco; Noreña, Carolina

    2005-12-01

    The free-living Platyhelminthes of the Amazon basin are poorly known. Presently only four turbellarian species have been mentioned from the Amazon river, a fact that confirms the lack of information on this kind of faunas in this huge basin. Three new species of Gieysztoria from Amazonian floodplain in Peru are described herein: G. chiqchi n. sp., G. kasasapa n. sp. and G. sasa n. sp. The samples were taken in the Pacaya-Samiria National Reserve (Peru) during September 2002. Besides the usual description of the stylet based on whole mounted specimens, we provide a complementary description using SEM, which allowed differentiation of the new species within the currently yet imperfect picture of the Amazonian turbellarian fauna. Although further research is desired, current findings are suggestive of high diversity of free-living Turbellaria in the surveyed region. PMID:16462104

  17. Planarians as a Model to Assess In Vivo the Role of Matrix Metalloproteinase Genes during Homeostasis and Regeneration

    PubMed Central

    Isolani, Maria Emilia; Abril, Josep F.; Saló, Emili; Deri, Paolo; Bianucci, Anna Maria; Batistoni, Renata

    2013-01-01

    Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results

  18. Light-induced depigmentation in planarians models the pathophysiology of acute porphyrias.

    PubMed

    Stubenhaus, Bradford M; Dustin, John P; Neverett, Emily R; Beaudry, Megan S; Nadeau, Leanna E; Burk-McCoy, Ethan; He, Xinwen; Pearson, Bret J; Pellettieri, Jason

    2016-01-01

    Porphyrias are disorders of heme metabolism frequently characterized by extreme photosensitivity. This symptom results from accumulation of porphyrins, tetrapyrrole intermediates in heme biosynthesis that generate reactive oxygen species when exposed to light, in the skin of affected individuals. Here we report that in addition to producing an ommochrome body pigment, the planarian flatworm Schmidtea mediterranea generates porphyrins in its subepithelial pigment cells under physiological conditions, and that this leads to pigment cell loss when animals are exposed to intense visible light. Remarkably, porphyrin biosynthesis and light-induced depigmentation are enhanced by starvation, recapitulating a common feature of some porphyrias - decreased nutrient intake precipitates an acute manifestation of the disease. Our results establish planarians as an experimentally tractable animal model for research into the pathophysiology of acute porphyrias, and potentially for the identification of novel pharmacological interventions capable of alleviating porphyrin-mediated photosensitivity or decoupling dieting and fasting from disease pathogenesis. PMID:27240733

  19. Go ahead, grow a head! A planarian's guide to anterior regeneration

    PubMed Central

    2016-01-01

    Abstract The unique ability of some planarian species to regenerate a head de novo, including a functional brain, provides an experimentally accessible system in which to study the mechanisms underlying regeneration. Here, we summarize the current knowledge on the key steps of planarian head regeneration (head‐versus‐tail decision, anterior pole formation and head patterning) and their molecular and cellular basis. Moreover, instructive properties of the anterior pole as a putative organizer and in coordinating anterior midline formation are discussed. Finally, we highlight that regeneration initiation occurs in a two‐step manner and hypothesize that wound‐induced and existing positional cues interact to detect tissue loss and together determine the appropriate regenerative outcomes. PMID:27606065

  20. teashirt is required for head-versus-tail regeneration polarity in planarians.

    PubMed

    Owen, Jared H; Wagner, Daniel E; Chen, Chun-Chieh; Petersen, Christian P; Reddien, Peter W

    2015-03-15

    Regeneration requires that the identities of new cells are properly specified to replace missing tissues. The Wnt signaling pathway serves a central role in specifying posterior cell fates during planarian regeneration. We identified a gene encoding a homolog of the Teashirt family of zinc-finger proteins in the planarian Schmidtea mediterranea to be a target of Wnt signaling in intact animals and at posterior-facing wounds. Inhibition of Smed-teashirt (teashirt) by RNA interference (RNAi) resulted in the regeneration of heads in place of tails, a phenotype previously observed with RNAi of the Wnt pathway genes β-catenin-1, wnt1, Dvl-1/2 or wntless. teashirt was required for β-catenin-1-dependent activation of posterior genes during regeneration. These findings identify teashirt as a transcriptional target of Wnt signaling required for Wnt-mediated specification of posterior blastemas. PMID:25725068

  1. The More the Merrier?. Entropy and Statistics of Asexual Reproduction in Freshwater Planarians

    NASA Astrophysics Data System (ADS)

    Quinodoz, Sofia; Thomas, Michael A.; Dunkel, Jörn; Schötz, Eva-Maria

    2011-04-01

    The trade-off between traits in life-history strategies has been widely studied for sexual and parthenogenetic organisms, but relatively little is known about the reproduction strategies of asexual animals. Here, we investigate clonal reproduction in the freshwater planarian Schmidtea mediterranea, an important model organism for regeneration and stem cell research. We find that these flatworms adopt a randomized reproduction strategy that comprises both asymmetric binary fission and fragmentation (generation of multiple offspring during a reproduction cycle). Fragmentation in planarians has primarily been regarded as an abnormal behavior in the past; using a large-scale experimental approach, we now show that about one third of the reproduction events in S. mediterranea are fragmentations, implying that fragmentation is part of their normal reproductive behavior. Our analysis further suggests that certain characteristic aspects of the reproduction statistics can be explained in terms of a maximum relative entropy principle.

  2. Go ahead, grow a head! A planarian's guide to anterior regeneration.

    PubMed

    Owlarn, Suthira; Bartscherer, Kerstin

    2016-06-01

    The unique ability of some planarian species to regenerate a head de novo, including a functional brain, provides an experimentally accessible system in which to study the mechanisms underlying regeneration. Here, we summarize the current knowledge on the key steps of planarian head regeneration (head-versus-tail decision, anterior pole formation and head patterning) and their molecular and cellular basis. Moreover, instructive properties of the anterior pole as a putative organizer and in coordinating anterior midline formation are discussed. Finally, we highlight that regeneration initiation occurs in a two-step manner and hypothesize that wound-induced and existing positional cues interact to detect tissue loss and together determine the appropriate regenerative outcomes. PMID:27606065

  3. The protective effect of blueberry anthocyanins against perfluorooctanoic acid-induced disturbance in planarian (Dugesia japonica).

    PubMed

    Yuan, Zuoqing; Zhang, Jianyong; Tu, Changchao; Wang, Zhijing; Xin, Wenpeng

    2016-05-01

    The influence of blueberry anthocyanins on perfluorooctanoic acid (PFOA)-induced stress response in planarian mitochondria was investigated. PFOA at 15mg/L and anthocyanins at 10 or 20mg/L were individually and simultaneously administered to planarians for up to 10d. The results showed PFOA treatment induced an increase in mitochondrial permeability transition pore opening and a decrease antioxidant capacity and enzyme activities. In anthocyanin treated animals, the activity of succinate dehydrogenase, cytochrome oxidase and monoamine oxidase increased, but mitochondrial permeability transition pore opening decreased and total antioxidant capacity increased. An improvement in above-mentioned physiological and biochemical parameters was found in the combined PFOA and anthocyanin treated animals, in a dose-dependent manner. Anthocyanins attenuated the PFOA induced toxicity; antioxidant capacity and enzyme activities are involved in the protective mechanism of anthocyanins. PMID:26836138

  4. Single-cell analysis reveals functionally distinct classes within the planarian stem cell compartment

    PubMed Central

    van Wolfswinkel, Josien C.; Wagner, Daniel E.; Reddien, Peter W.

    2014-01-01

    Planarians are flatworms capable of regenerating any missing body region. This capacity is mediated by neoblasts, a proliferative cell population that contains pluripotent stem cells. Although population-based studies have revealed many neoblast characteristics, whether functionally distinct classes exist within this population is unclear. Here, we used high-dimensional single-cell transcriptional profiling from over a thousand individual neoblasts to directly compare gene expression fingerprints during homeostasis and regeneration. We identified two prominent neoblast classes that we named ζ (zeta) and σ (sigma). Zeta-neoblasts encompass specified cells that give rise to an abundant postmitotic lineage including epidermal cells, and are not required for regeneration. By contrast, sigma-neoblasts proliferate in response to injury, possess broad lineage capacity, and can give rise to zeta-neoblasts. These findings present a new view of planarian neoblasts, in which the population is comprised of two major and functionally distinct cellular compartments. PMID:25017721

  5. teashirt is required for head-versus-tail regeneration polarity in planarians

    PubMed Central

    Owen, Jared H.; Wagner, Daniel E.; Chen, Chun-Chieh; Petersen, Christian P.; Reddien, Peter W.

    2015-01-01

    Regeneration requires that the identities of new cells are properly specified to replace missing tissues. The Wnt signaling pathway serves a central role in specifying posterior cell fates during planarian regeneration. We identified a gene encoding a homolog of the Teashirt family of zinc-finger proteins in the planarian Schmidtea mediterranea to be a target of Wnt signaling in intact animals and at posterior-facing wounds. Inhibition of Smed-teashirt (teashirt) by RNA interference (RNAi) resulted in the regeneration of heads in place of tails, a phenotype previously observed with RNAi of the Wnt pathway genes β-catenin-1, wnt1, Dvl-1/2 or wntless. teashirt was required for β-catenin-1-dependent activation of posterior genes during regeneration. These findings identify teashirt as a transcriptional target of Wnt signaling required for Wnt-mediated specification of posterior blastemas. PMID:25725068

  6. A taste for exotic food: Neotropical land planarians feeding on an invasive flatworm

    PubMed Central

    Boll, Piter K.; Rossi, Ilana; Amaral, Silvana V.

    2015-01-01

    Invasive species establish successfully in new habitats especially due to their ability to include new species in their diet and due to the freedom from natural enemies. However, native species may also adapt to the use of new elements in their ecosystem. The planarian Endeavouria septemlineata, first recorded in Hawaii, was later found in Brazil. Recently, we found it in human-disturbed areas in southern Brazil and here we investigate its interactions with other invertebrates both in the field and in the laboratory. We observed the species in the field during collecting activities and hence maintained some specimens alive in small terraria in the laboratory, where we offered different invertebrate species as potential prey and also put them in contact with native land planarians in order to examine their interaction. Both in the field and in the laboratory, E. septemlineata showed a gregarious behavior and was found feeding on woodlice, millipedes, earwigs and gastropods. In the laboratory, specimens often did not attack live prey, but immediately approached dead specimens, indicating a scavenging behavior. In an experiment using the slug Deroceras laeve and the woodlouse Atlantoscia floridana, there was a higher consumption of dead specimens of woodlice and slugs compared to live specimens, as well as a higher consumption of dead woodlice over dead slugs. Four native land planarians of the genus Obama and one of the genus Paraba attacked and consumed E. septemlineata, which, after the beginning of the attack, tried to escape by tumbling or using autotomy. As a scavenger, E. septemlineata would have no impact on the populations of species used as food, but could possibly exclude native scavengers by competition. On the other hand, its consumption by native land planarians may control its spread and thus reduce its impact on the ecosystem. PMID:26500817

  7. Genome-Wide Analyses Reveal a Role for Peptide Hormones in Planarian Germline Development

    PubMed Central

    Collins, James J.; Hou, Xiaowen; Romanova, Elena V.; Lambrus, Bramwell G.; Miller, Claire M.; Saberi, Amir; Sweedler, Jonathan V.; Newmark, Phillip A.

    2010-01-01

    Bioactive peptides (i.e., neuropeptides or peptide hormones) represent the largest class of cell-cell signaling molecules in metazoans and are potent regulators of neural and physiological function. In vertebrates, peptide hormones play an integral role in endocrine signaling between the brain and the gonads that controls reproductive development, yet few of these molecules have been shown to influence reproductive development in invertebrates. Here, we define a role for peptide hormones in controlling reproductive physiology of the model flatworm, the planarian Schmidtea mediterranea. Based on our observation that defective neuropeptide processing results in defects in reproductive system development, we employed peptidomic and functional genomic approaches to characterize the planarian peptide hormone complement, identifying 51 prohormone genes and validating 142 peptides biochemically. Comprehensive in situ hybridization analyses of prohormone gene expression revealed the unanticipated complexity of the flatworm nervous system and identified a prohormone specifically expressed in the nervous system of sexually reproducing planarians. We show that this member of the neuropeptide Y superfamily is required for the maintenance of mature reproductive organs and differentiated germ cells in the testes. Additionally, comparative analyses of our biochemically validated prohormones with the genomes of the parasitic flatworms Schistosoma mansoni and Schistosoma japonicum identified new schistosome prohormones and validated half of all predicted peptide-encoding genes in these parasites. These studies describe the peptide hormone complement of a flatworm on a genome-wide scale and reveal a previously uncharacterized role for peptide hormones in flatworm reproduction. Furthermore, they suggest new opportunities for using planarians as free-living models for understanding the reproductive biology of flatworm parasites. PMID:20967238

  8. Effects of nonionic and ionic surfactants on survival, oxidative stress, and cholinesterase activity of planarian.

    PubMed

    Li, Mei-Hui

    2008-02-01

    Eight widely used surfactants (cetyltrimethylammonium bromide; CTAB, benzethonium chloride; Hyamine 1622, 4-nonylphenol; NP, octylphenol ethoxylate; Triton X-100, dodecylbenzene sulfonate; LAS, lauryl sulfate; SDS, pentadecafluorooctanoic acid; PFOA, and perfluorooctane sulfonate; PFOS) were selected to examine their acute toxicities and effects on oxidative stress and cholinesterase (ChE) activities in Dugesia japonica. The differences in acute toxicity among eight surfactants to planarians were at least in the range of three orders of magnitudes. The toxicity rank of surfactants according to estimated 48-h LC(50) was SDS>NP>LAS>Hyamine 1622>CTAB>Triton X-100>PFOS>PFOA. The toxicity rank of surfactants according to 96-h LC(50) was as follows: SDS>CTAB>NP>LAS>Hyamine 1622>Triton X-100>PFOS>PFOA. There were significant increases in catalase activities in planarians exposed to LAS at nominal concentrations of 0.5 or 1 mgl(-1) and to PFOS at nominal concentrations of 5 or 10 mgl(-1) after 48-h exposure. Inhibitions of ChE activities were found in planarians exposed to Hyamine 1622 at all concentrations tested, to PFOS at nominal concentration of 10 mgl(-1), to PFOA at nominal concentrations of 50 or 100 mgl(-1) and to NP at nominal concentration of 0.5 mgl(-1). A significant increase in ChE activities was also observed in planarian exposed to Triton X-100 at nominal concentration of 5 mgl(-1). The implication of ChE inhibition by NP, PFOS and PFOA on neurological and behavioral effects in aquatic animals requires further investigation. PMID:17905407

  9. A taste for exotic food: Neotropical land planarians feeding on an invasive flatworm.

    PubMed

    Boll, Piter K; Rossi, Ilana; Amaral, Silvana V; Leal-Zanchet, Ana

    2015-01-01

    Invasive species establish successfully in new habitats especially due to their ability to include new species in their diet and due to the freedom from natural enemies. However, native species may also adapt to the use of new elements in their ecosystem. The planarian Endeavouria septemlineata, first recorded in Hawaii, was later found in Brazil. Recently, we found it in human-disturbed areas in southern Brazil and here we investigate its interactions with other invertebrates both in the field and in the laboratory. We observed the species in the field during collecting activities and hence maintained some specimens alive in small terraria in the laboratory, where we offered different invertebrate species as potential prey and also put them in contact with native land planarians in order to examine their interaction. Both in the field and in the laboratory, E. septemlineata showed a gregarious behavior and was found feeding on woodlice, millipedes, earwigs and gastropods. In the laboratory, specimens often did not attack live prey, but immediately approached dead specimens, indicating a scavenging behavior. In an experiment using the slug Deroceras laeve and the woodlouse Atlantoscia floridana, there was a higher consumption of dead specimens of woodlice and slugs compared to live specimens, as well as a higher consumption of dead woodlice over dead slugs. Four native land planarians of the genus Obama and one of the genus Paraba attacked and consumed E. septemlineata, which, after the beginning of the attack, tried to escape by tumbling or using autotomy. As a scavenger, E. septemlineata would have no impact on the populations of species used as food, but could possibly exclude native scavengers by competition. On the other hand, its consumption by native land planarians may control its spread and thus reduce its impact on the ecosystem. PMID:26500817

  10. Two distinct roles of the yorkie/yap gene during homeostasis in the planarian Dugesia japonica.

    PubMed

    Hwang, Byulnim; An, Yang; Agata, Kiyokazu; Umesono, Yoshihiko

    2015-04-01

    Adult planarians possess somatic pluripotent stem cells called neoblasts that give rise to all missing cell types during regeneration and homeostasis. Recent studies revealed that the Yorkie (Yki)/Yes-associated protein (YAP) transcriptional coactivator family plays an important role in the regulation of tissue growth during development and regeneration, and therefore we investigated the role of a planarian yki-related gene (termed Djyki) during regeneration and homeostasis of the freshwater planarian Dugesia japonica. We found that knockdown of the function of Djyki by RNA interference (RNAi) downregulated neoblast proliferation and caused regeneration defects after amputation. In addition, Djyki RNAi caused edema during homeostasis. These seemingly distinct defects induced by Djyki RNAi were rescued by simultaneous RNAi of a planarian mats-related gene (termed Djmats), suggesting an important role of Djmats in the negative regulation of Djyki, in accordance with the conservation of the functional relationship of these two genes during the course of evolution. Interestingly, Djyki RNAi did not prevent normal protonephridial structure, suggesting that Djyki RNAi induced the edema phenotype without affecting the excretory system. Further analyses revealed that increased expression of the D. japonica gene DjaquaporinA (DjaqpA), which belongs to a large gene family that encodes a water channel protein for the regulation of transcellular water flow, promoted the induction of edema, but not defects in neoblast dynamics, in Djyki(RNAi) animals. Thus, we conclude that Djyki plays two distinct roles in the regulation of active proliferation of stem cells and in osmotic water transport across the body surface in D. japonica. PMID:25708270

  11. The planarian P2X homolog in the regulation of asexual reproduction.

    PubMed

    Sakurai, Toshihide; Lee, Hayoung; Kashima, Makoto; Saito, Yumi; Hayashi, Tetsutaro; Kudome-Takamatsu, Tomomi; Nishimura, Osamu; Agata, Kiyokazu; Shibata, Norito

    2012-01-01

    The growth in size of freshwater planarians in response to nutrient intake is limited by the eventual separation of tail and body fragments in a process called fission. The resulting tail fragment regenerates the entire body as an artificially amputated tail fragment would do, and the body fragment regenerates a tail, resulting in two whole planarians. This regenerative ability is supported by pluripotent somatic stem cells, called neoblasts, which are distributed throughout almost the entire body of the planarian. Neoblasts are the only planarian cells with the ability to continuously proliferate and give rise to all types of cells during regeneration, asexual reproduction, homeostasis, and growth. In order to investigate the molecular characteristics of neoblasts, we conducted an extensive search for neoblast-specific genes using the High Coverage Expression Profiling (HiCEP) method, and tested the function of the resulting candidates by RNAi. Disruption of the expression of one candidate gene, DjP2X-A (Dugesia japonica membrane protein P2X homologue), resulted in a unique phenotype. DjP2X-A RNAi leads to an increase of fission events upon feeding. We confirmed by immunohistochemistry that DjP2X-A is a membrane protein, and elucidated its role in regulating neoblast proliferation, thereby explaining its unique phenotype. We found that DjP2X-A decreases the burst of neoblast proliferation that normally occurs after feeding. We also found that DjP2X-A is required for normal proliferation in starved animals. We propose that DjP2X-A modulates stem cell proliferation in response to the nutritional condition. PMID:22451005

  12. Guarana Provides Additional Stimulation over Caffeine Alone in the Planarian Model

    PubMed Central

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R.; Constable, Mic Andre; Mulligan, Margaret E.; Voura, Evelyn B.

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  13. PIWI homologs mediate histone H4 mRNA localization to planarian chromatoid bodies.

    PubMed

    Rouhana, Labib; Weiss, Jennifer A; King, Ryan S; Newmark, Phillip A

    2014-07-01

    The well-known regenerative abilities of planarian flatworms are attributed to a population of adult stem cells called neoblasts that proliferate and differentiate to produce all cell types. A characteristic feature of neoblasts is the presence of large cytoplasmic ribonucleoprotein granules named chromatoid bodies, the function of which has remained largely elusive. This study shows that histone mRNAs are a common component of chromatoid bodies. Our experiments also demonstrate that accumulation of histone mRNAs, which is typically restricted to the S phase of eukaryotic cells, is extended during the cell cycle of neoblasts. The planarian PIWI homologs SMEDWI-1 and SMEDWI-3 are required for proper localization of germinal histone H4 (gH4) mRNA to chromatoid bodies. The association between histone mRNA and chromatoid body components extends beyond gH4 mRNA, since transcripts of other core histone genes were also found in these structures. Additionally, piRNAs corresponding to loci of every core histone type have been identified. Altogether, this work provides evidence that links PIWI proteins and chromatoid bodies to histone mRNA regulation in planarian stem cells. The molecular similarities between neoblasts and undifferentiated cells of other organisms raise the possibility that PIWI proteins might also regulate histone mRNAs in stem cells and germ cells of other metazoans. PMID:24903754

  14. The use of planarians as in vivo animal model to study laser biomodulation effects

    NASA Astrophysics Data System (ADS)

    Munin, Egberto; Garcia, Neila Maria Rocha; Braz, Allison Gustavo; de Souza, Sandra Cristina; Alves, Leandro Procópio; Salgado, Miguel Angel Castillo; Pilla, Viviane

    2007-02-01

    A variety of effects is attributed to the photo stimulation of tissues, such as improved healing of ulcers, analgesic and anti-inflammatory effects, stimulation of the proliferation of cells of different origins and stimulation of bone repair. Some investigations that make qualitative evaluations, like wound healing and evaluation of pain and edema, can be conducted in human subjects. However, deeper investigations on the mechanisms of action of the light stimulus and other quantitative works that requires biopsies or destructive analysis has to be carried out in animal models or in cell cultures. In this work, we propose the use of planarians as a model to study laser-tissue interaction. Contrasting with cell cultures and unicellular organisms, planarians are among the simplest organism having tissue layers, central nerve system, digestive and excretory system that might have been platforms for the evolution of the complex and highly organized tissues and organs found in higher organisms. For the present study, 685 nm laser radiation was employed. Planarians were cut transversally, in a plane posterior to the auricles. The body fragments were left to regenerate and the proliferation dynamics of stem cells was studied by using histological analysis. Maximum cell count was obtained for the laser treated group at the 4 th experimental day. At that experimental time, we also had the largest difference between the irradiated and the non-irradiated control group. We concluded that the studied flatworm could be an interesting animal model for in vivo studies of laser-tissue interactions.

  15. Egr-5 is a post-mitotic regulator of planarian epidermal differentiation

    PubMed Central

    Tu, Kimberly C; Cheng, Li-Chun; TK Vu, Hanh; Lange, Jeffrey J; McKinney, Sean A; Seidel, Chris W; Sánchez Alvarado, Alejandro

    2015-01-01

    Neoblasts are an abundant, heterogeneous population of adult stem cells (ASCs) that facilitate the maintenance of planarian tissues and organs, providing a powerful system to study ASC self-renewal and differentiation dynamics. It is unknown how the collective output of neoblasts transit through differentiation pathways to produce specific cell types. The planarian epidermis is a simple tissue that undergoes rapid turnover. We found that as epidermal progeny differentiate, they progress through multiple spatiotemporal transition states with distinct gene expression profiles. We also identified a conserved early growth response family transcription factor, egr-5, that is essential for epidermal differentiation. Disruption of epidermal integrity by egr-5 RNAi triggers a global stress response that induces the proliferation of neoblasts and the concomitant expansion of not only epidermal, but also multiple progenitor cell populations. Our results further establish the planarian epidermis as a novel paradigm to uncover the molecular mechanisms regulating ASC specification in vivo. DOI: http://dx.doi.org/10.7554/eLife.10501.001 PMID:26457503

  16. PIWI homologs mediate Histone H4 mRNA localization to planarian chromatoid bodies

    PubMed Central

    Rouhana, Labib; Weiss, Jennifer A.; King, Ryan S.; Newmark, Phillip A.

    2014-01-01

    The well-known regenerative abilities of planarian flatworms are attributed to a population of adult stem cells called neoblasts that proliferate and differentiate to produce all cell types. A characteristic feature of neoblasts is the presence of large cytoplasmic ribonucleoprotein granules named chromatoid bodies, the function of which has remained largely elusive. This study shows that histone mRNAs are a common component of chromatoid bodies. Our experiments also demonstrate that accumulation of histone mRNAs, which is typically restricted to the S phase of eukaryotic cells, is extended during the cell cycle of neoblasts. The planarian PIWI homologs SMEDWI-1 and SMEDWI-3 are required for proper localization of germinal histone H4 (gH4) mRNA to chromatoid bodies. The association between histone mRNA and chromatoid body components extends beyond gH4 mRNA, since transcripts of other core histone genes were also found in these structures. Additionally, piRNAs corresponding to loci of every core histone type have been identified. Altogether, this work provides evidence that links PIWI proteins and chromatoid bodies to histone mRNA regulation in planarian stem cells. The molecular similarities between neoblasts and undifferentiated cells of other organisms raise the possibility that PIWI proteins might also regulate histone mRNAs in stem cells and germ cells of other metazoans. PMID:24903754

  17. The maintenance and regeneration of the planarian excretory system are regulated by EGFR signaling.

    PubMed

    Rink, Jochen C; Vu, Hanh Thi-Kim; Sánchez Alvarado, Alejandro

    2011-09-01

    The maintenance of organs and their regeneration in case of injury are crucial to the survival of all animals. High rates of tissue turnover and nearly unlimited regenerative capabilities make planarian flatworms an ideal system with which to investigate these important processes, yet little is known about the cell biology and anatomy of their organs. Here we focus on the planarian excretory system, which consists of internal protonephridial tubules. We find that these assemble into complex branching patterns with a stereotyped succession of cell types along their length. Organ regeneration is likely to originate from a precursor structure arising in the blastema, which undergoes extensive branching morphogenesis. In an RNAi screen of signaling molecules, we identified an EGF receptor (Smed-EGFR-5) as a crucial regulator of branching morphogenesis and maintenance. Overall, our characterization of the planarian protonephridial system establishes a new paradigm for regenerative organogenesis and provides a platform for exploring its functional and evolutionary homologies with vertebrate excretory systems. PMID:21828097

  18. Loss of DNA mismatch repair imparts a selective advantage in planarian adult stem cells.

    PubMed

    Hollenbach, Jessica P; Resch, Alissa M; Palakodeti, Dasaradhi; Graveley, Brenton R; Heinen, Christopher D

    2011-01-01

    Lynch syndrome (LS) leads to an increased risk of early-onset colorectal and other types of cancer and is caused by germline mutations in DNA mismatch repair (MMR) genes. Loss of MMR function results in a mutator phenotype that likely underlies its role in tumorigenesis. However, loss of MMR also results in the elimination of a DNA damage-induced checkpoint/apoptosis activation barrier that may allow damaged cells to grow unchecked. A fundamental question is whether loss of MMR provides pre-cancerous stem cells an immediate selective advantage in addition to establishing a mutator phenotype. To test this hypothesis in an in vivo system, we utilized the planarian Schmidtea mediterranea which contains a significant population of identifiable adult stem cells. We identified a planarian homolog of human MSH2, a MMR gene which is mutated in 38% of LS cases. The planarian Smed-msh2 is expressed in stem cells and some progeny. We depleted Smed-msh2 mRNA levels by RNA-interference and found a striking survival advantage in these animals treated with a cytotoxic DNA alkylating agent compared to control animals. We demonstrated that this tolerance to DNA damage is due to the survival of mitotically active, MMR-deficient stem cells. Our results suggest that loss of MMR provides an in vivo survival advantage to the stem cell population in the presence of DNA damage that may have implications for tumorigenesis. PMID:21747960

  19. Guarana provides additional stimulation over caffeine alone in the planarian model.

    PubMed

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R; Constable, Mic Andre; Mulligan, Margaret E; Voura, Evelyn B

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  20. A Bruno-like gene is required for stem cell maintenance in planarians.

    PubMed

    Guo, Tingxia; Peters, Antoine H F M; Newmark, Phillip A

    2006-08-01

    The regenerative abilities of freshwater planarians are based on neoblasts, stem cells maintained throughout the animal's life. We show that a member of the Bruno-like family of RNA binding proteins is critical for regulating neoblasts in the planarian Schmidtea mediterranea. Smed-bruno-like (bruli) mRNA and protein are expressed in neoblasts and the central nervous system. Following bruli RNAi, which eliminates detectable Bruli protein, planarians initiate the proliferative response to amputation and form small blastemas but then undergo tissue regression and lysis. We characterize the neoblast population by using antibodies recognizing SMEDWI-1 and Histone H4 (monomethyl-K20) and cell-cycle markers to label subsets of neoblasts and their progeny. bruli knockdown results in a dramatic reduction/elimination of neoblasts. Our analyses indicate that neoblasts lacking Bruli can respond to wound stimuli and generate progeny that can form blastemas and differentiate; yet, they are unable to self-renew. These results suggest that Bruli is required for stem cell maintenance. PMID:16890156

  1. Identification of small non-coding RNAs in the planarian Dugesia japonica via deep sequencing.

    PubMed

    Qin, Yun-Fei; Zhao, Jin-Mei; Bao, Zhen-Xia; Zhu, Zhao-Yu; Mai, Jia; Huang, Yi-Bo; Li, Jian-Biao; Chen, Ge; Lu, Ping; Chen, San-Jun; Su, Lin-Lin; Fang, Hui-Min; Lu, Ji-Ke; Zhang, Yi-Zhe; Zhang, Shou-Tao

    2012-05-01

    Freshwater planarian flatworm possesses an extraordinary ability to regenerate lost body parts after amputation; it is perfect organism model in regeneration and stem cell biology. Recently, small RNAs have been an increasing concern and studied in many aspects, including regeneration and stem cell biology, among others. In the current study, the large-scale cloning and sequencing of sRNAs from the intact and regenerative planarian Dugesia japonica are reported. Sequence analysis shows that sRNAs between 18nt and 40nt are mainly microRNAs and piRNAs. In addition, 209 conserved miRNAs and 12 novel miRNAs are identified. Especially, a better screening target method, negative-correlation relationship of miRNAs and mRNA, is adopted to improve target prediction accuracy. Similar to miRNAs, a diverse population of piRNAs and changes in the two samples are also listed. The present study is the first to report on the important role of sRNAs during planarian Dugesia japonica regeneration. PMID:22425900

  2. Allometric scaling and proportion regulation in the freshwater planarian Schmidtea mediterranea.

    PubMed

    Oviedo, Néstor J; Newmark, Phillip A; Sánchez Alvarado, Alejandro

    2003-02-01

    The regulation of scale and proportion in living organisms is an intriguing and enduring problem of biology. Regulatory mechanisms for controlling body size and proportion are clearly illustrated by the regeneration of missing body parts after amputation, in which the newly regenerated tissues ultimately attain a size that is anatomically congruent with the size of the rest of the organism. Understanding the molecular processes underpinning scaling would have deep consequences for our comprehension of tissue regeneration, developmental ontogeny, growth, and evolution. Although many theories have been put forward to explain this process, it is interesting that no satisfactory mechanistic explanation is currently available to explain scalar relationships. We chose to investigate the freshwater planarian, a commonly used model system for the study of metazoan regeneration, to delineate a strategy for the molecular dissection of scale and proportion mechanisms in metazoans. Here, we report on the cloning and discrete expression pattern of a novel planarian gene, which shares homology with the DEG/ENaC super-family of sodium channels. We have named H.112.3c cintillo ("head ribbon" in Spanish) and present a strategy for using the expression of this gene to monitor scale and proportion regulation during regeneration, growth and degrowth in the freshwater planarian Schmidtea mediterranea. PMID:12557210

  3. Early exposure of rotating magnetic fields promotes central nervous regeneration in planarian Girardia sinensis.

    PubMed

    Chen, Qiang; Lin, Gui-Miao; Wu, Nan; Tang, Sheng-Wei; Zheng, Zhi-Jia; Lin, Marie Chia-Mi; Xu, Gai-Xia; Liu, Hao; Deng, Yue-Yue; Zhang, Xiao-Yun; Chen, Si-Ping; Wang, Xiao-Mei; Niu, Han-Ben

    2016-05-01

    Magnetic field exposure is an accepted safe and effective modality for nerve injury. However, it is clinically used only as a supplement or salvage therapy at the later stage of treatment. Here, we used a planarian Girardia sinensis decapitated model to investigate beneficial effects of early rotary non-uniform magnetic fields (RMFs) exposure on central nervous regeneration. Our results clearly indicated that magnetic stimulation induced from early RMFs exposure significantly promoted neural regeneration of planarians. This stimulating effect is frequency and intensity dependent. Optimum effects were obtained when decapitated planarians were cultured at 20 °C, starved for 3 days before head-cutting, and treated with 6 Hz 0.02 T RMFs. At early regeneration stage, RMFs exposure eliminated edema around the wound and facilitated subsequent formation of blastema. It also accelerated cell proliferation and recovery of neuron functionality. Early RMFs exposure up-regulated expression of neural regeneration related proteins, EGR4 and Netrin 2, and mature nerve cell marker proteins, NSE and NPY. These results suggest that RMFs therapy produced early and significant benefit in central nervous regeneration, and should be clinically used at the early stage of neural regeneration, with appropriate optimal frequency and intensity. Bioelectromagnetics. Bioelectromagnetics. 37:244-255, 2016. © 2016 Wiley Periodicals, Inc. PMID:27061713

  4. Planarian regeneration involves distinct stem cell responses to wounds and tissue absence

    PubMed Central

    Wenemoser, Danielle; Reddien, Peter W.

    2010-01-01

    Regeneration requires signaling from a wound site for detection of the wound, and a mechanism that determines the nature of the injury to specify the appropriate regenerative response. Wound signals and tissue responses to wounds that elicit regeneration remain poorly understood. Planarians are able to regenerate from essentially any type of injury and present a novel system for the study of wound responses in regeneration initiation. Newly developed molecular and cellular tools now enable study of regeneration initiation using the planarian Schmidtea mediterranea. Planarian regeneration requires adult stem cells called neoblasts and amputation triggers two peaks in neoblast mitoses early in regeneration. We demonstrate that the first mitotic peak is a body-wide response to any injury and that a second, local, neoblast response is induced only when injury results in missing tissue. This second response was characterized by recruitment of neoblasts to wounds, even in areas that lack neoblasts in the intact animal. Subsequently, these neoblasts were induced to divide and differentiate near the wound, leading to formation of new tissue. We conclude 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. PMID:20599901

  5. Smed-Evi/Wntless is required for beta-catenin-dependent and -independent processes during planarian regeneration.

    PubMed

    Adell, Teresa; Salò, Emili; Boutros, Michael; Bartscherer, Kerstin

    2009-03-01

    Planarians can regenerate a whole animal from only a small piece of their body, and have become an important model for stem cell biology. To identify regenerative processes dependent on Wnt growth factors in the planarian Schmidtea mediterranea (Smed), we analyzed RNAi phenotypes of Evi, a transmembrane protein specifically required for the secretion of Wnt ligands. We show that, during regeneration, Smed-evi loss-of-function prevents posterior identity, leading to two-headed planarians that resemble Smed-beta-catenin1 RNAi animals. In addition, we observe regeneration defects of the nervous system that are not found after Smed-beta-catenin1 RNAi. By systematic knockdown of all putative Smed Wnts in regenerating planarians, we identify Smed-WntP-1 and Smed-Wnt11-2 as the putative posterior organizers, and demonstrate that Smed-Wnt5 is a regulator of neuronal organization and growth. Thus, our study provides evidence that planarian Wnts are major regulators of regeneration, and that they signal through beta-catenin-dependent and -independent pathways. PMID:19211673

  6. Smed-dynA-1 is a planarian nervous system specific dynamin 1 homolog required for normal locomotion.

    PubMed

    Talbot, Jared A; Currie, Ko W; Pearson, Bret J; Collins, Eva-Maria S

    2014-01-01

    Dynamins are GTPases that are required for separation of vesicles from the plasma membrane and thus are key regulators of endocytosis in eukaryotic cells. This role for dynamin proteins is especially crucial for the proper function of neurons, where they ensure that synaptic vesicles and their neurotransmitter cargo are recycled in the presynaptic cell. Here we have characterized the dynamin protein family in the freshwater planarian Schmidtea mediterranea and showed that it possesses six dynamins with tissue specific expression profiles. Of these six planarian homologs, two are necessary for normal tissue homeostasis, and the loss of another, Smed-dynA-1, leads to an abnormal behavioral phenotype, which we have quantified using automated center of mass tracking. Smed-dynA-1 is primarily expressed in the planarian nervous system and is a functional homolog of the mammalian Dynamin I. The distinct expression profiles of the six dynamin genes makes planarians an interesting new system to reveal novel dynamin functions, which may be determined by their differential tissue localization. The observed complexity of neurotransmitter regulation combined with the tools of quantitative behavioral assays as a functional readout for neuronal activity, renders planarians an ideal system for studying how the nervous system controls behavior. PMID:24950970

  7. Smed-dynA-1 is a planarian nervous system specific dynamin 1 homolog required for normal locomotion

    PubMed Central

    Talbot, Jared A.; Currie, Ko W.; Pearson, Bret J.; Collins, Eva-Maria S.

    2014-01-01

    ABSTRACT Dynamins are GTPases that are required for separation of vesicles from the plasma membrane and thus are key regulators of endocytosis in eukaryotic cells. This role for dynamin proteins is especially crucial for the proper function of neurons, where they ensure that synaptic vesicles and their neurotransmitter cargo are recycled in the presynaptic cell. Here we have characterized the dynamin protein family in the freshwater planarian Schmidtea mediterranea and showed that it possesses six dynamins with tissue specific expression profiles. Of these six planarian homologs, two are necessary for normal tissue homeostasis, and the loss of another, Smed-dynA-1, leads to an abnormal behavioral phenotype, which we have quantified using automated center of mass tracking. Smed-dynA-1 is primarily expressed in the planarian nervous system and is a functional homolog of the mammalian Dynamin I. The distinct expression profiles of the six dynamin genes makes planarians an interesting new system to reveal novel dynamin functions, which may be determined by their differential tissue localization. The observed complexity of neurotransmitter regulation combined with the tools of quantitative behavioral assays as a functional readout for neuronal activity, renders planarians an ideal system for studying how the nervous system controls behavior. PMID:24950970

  8. Conserved functional antagonism of CELF and MBNL proteins controls stem cell-specific alternative splicing in planarians.

    PubMed

    Solana, Jordi; Irimia, Manuel; Ayoub, Salah; Orejuela, Marta Rodriguez; Zywitza, Vera; Jens, Marvin; Tapial, Javier; Ray, Debashish; Morris, Quaid; Hughes, Timothy R; Blencowe, Benjamin J; Rajewsky, Nikolaus

    2016-01-01

    In contrast to transcriptional regulation, the function of alternative splicing (AS) in stem cells is poorly understood. In mammals, MBNL proteins negatively regulate an exon program specific of embryonic stem cells; however, little is known about the in vivo significance of this regulation. We studied AS in a powerful in vivo model for stem cell biology, the planarian Schmidtea mediterranea. We discover a conserved AS program comprising hundreds of alternative exons, microexons and introns that is differentially regulated in planarian stem cells, and comprehensively identify its regulators. We show that functional antagonism between CELF and MBNL factors directly controls stem cell-specific AS in planarians, placing the origin of this regulatory mechanism at the base of Bilaterians. Knockdown of CELF or MBNL factors lead to abnormal regenerative capacities by affecting self-renewal and differentiation sets of genes, respectively. These results highlight the importance of AS interactions in stem cell regulation across metazoans. PMID:27502555

  9. Diseases of cultured marine fishes caused by Platyhelminthes (Monogenea, Digenea, Cestoda).

    PubMed

    Ogawa, K

    2015-01-01

    Mariculture is a rapidly developing industrial sector. Generally, fish are maintained in net cages with high density. Cage culture systems allow uncontrolled flow of sea water containing potentially infectious stages of fish parasites. In such culture conditions, prevention of such parasitic infections is difficult for parasites with life cycles that complete within culture sites, among which monogeneans and blood flukes are the most important platyhelminthes. Intense monogenean infections induce respiratory and osmo-regulatory dysfunctions. A variety of control measures have been developed, including freshwater bath treatment and chemotherapy. The potential to control monogenean infections through selective breeding, modified culture techniques to avoid infection, and general fish health management are discussed. It should be noted that mariculture conditions have provided some host-specific monogeneans with a chance to expand their host ranges. Blood flukes sometimes induce mass mortality among farmed fish. In-feed administration of praziquantel is the best solution to treat infected fish. Some cases are described that show how international trade in marine fish has resulted in the spread of hitherto unknown parasites into indigenous farmed and wild fish. PMID:24998438

  10. Comparative study of adaptive radiations with an example using parasitic flatworms (Platyhelminthes): Cercomeria

    SciTech Connect

    Brooks, D.R.; McLennan, D.A. )

    1993-11-01

    Studies of adaptive radiations require robust phylogenies, estimates of species numbers for monophyletic groups within clades, assessments of the adaptive value of putative key innovations, and estimates of the frequency of speciation modes. Four criteria are necessary to identify an adaptive radiation within the parasitic platyhelminths: (1) a group contains significantly more species than its sister group, (2) species richness is apomorphic, (3) apomorphic traits enhance the potential for adaptively driven modes of speciation (sympatric speciation and speciation by peripheral isolation via host switching), and (4) the frequency of adaptively driven speciation modes is high within the group when compared with data from free-living groups. Only the species-rich Monogenea fulfill all four criteria. The Digenea and Eucestoda also are more species rich than their sister groups, their species richness is derived, and they possess unique characters that increase the potential for host switching to occur. However, because there is not enough information to determine whether the frequency of adaptive modes of speciation is high for those groups, we cannot yet assert that their radiations have been adaptive. 102 refs., 3 figs., 1 tab.

  11. Problematic barcoding in flatworms: A case-study on monogeneans and rhabdocoels (Platyhelminthes)

    PubMed Central

    Vanhove, Maarten P. M.; Tessens, Bart; Schoelinck, Charlotte; Jondelius, Ulf; Littlewood, D. Tim J.; Artois, Tom; Huyse, Tine

    2013-01-01

    Abstract Some taxonomic groups are less amenable to mitochondrial DNA barcoding than others. Due to the paucity of molecular information of understudied groups and the huge molecular diversity within flatworms, primer design has been hampered. Indeed, all attempts to develop universal flatworm-specific COI markers have failed so far. We demonstrate how high molecular variability and contamination problems limit the possibilities for barcoding using standard COI-based protocols in flatworms. As a consequence, molecular identification methods often rely on other widely applicable markers. In the case of Monogenea, a very diverse group of platyhelminth parasites, and Rhabdocoela, representing one-fourth of all free-living flatworm taxa, this has led to a relatively high availability of nuclear ITS and 18S/28S rDNA sequences on GenBank. In a comparison of the effectiveness in species assignment we conclude that mitochondrial and nuclear ribosomal markers perform equally well. In case intraspecific information is needed, rDNA sequences can guide the selection of the appropriate (i.e. taxon-specific) COI primers if available. PMID:24453567

  12. Inferring Regulatory Networks from Experimental Morphological Phenotypes: A Computational Method Reverse-Engineers Planarian Regeneration

    PubMed Central

    Lobo, Daniel; Levin, Michael

    2015-01-01

    Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method provides an automated

  13. Silencing of Smed-betacatenin1 generates radial-like hypercephalized planarians.

    PubMed

    Iglesias, Marta; Gomez-Skarmeta, Jose Luis; Saló, Emili; Adell, Teresa

    2008-04-01

    Little is known about the molecular mechanisms responsible for axis establishment during non-embryonic processes such as regeneration and homeostasis. To address this issue, we set out to analyze the role of the canonical Wnt pathway in planarians, flatworms renowned for their extraordinary morphological plasticity. Canonical Wnt signalling is an evolutionarily conserved mechanism to confer polarity during embryonic development, specifying the anteroposterior (AP) axis in most bilaterians and the dorsoventral (DV) axis in early vertebrate embryos. beta-Catenin is a key element in this pathway, although it is a bifunctional protein that is also involved in cell-cell adhesion. Here, we report the characterization of two beta-catenin homologs from Schmidtea mediterranea (Smed-betacatenin1/2). Loss of function of Smed-betacatenin1, but not Smed-betacatenin2, in both regenerating and intact planarians, generates radial-like hypercephalized planarians in which the AP axis disappears but the DV axis remains unaffected, representing a unique example of a striking body symmetry transformation. The radial-like hypercephalized phenotype demonstrates the requirement for Smed-betacatenin1 in AP axis re-establishment and maintenance, and supports a conserved role for canonical Wnt signalling in AP axis specification, whereas the role of beta-catenin in DV axis establishment would be a vertebrate innovation. When considered alongside the protein domains present in each S. mediterranea beta-catenin and the results of functional assays in Xenopus embryos demonstrating nuclear accumulation and axis induction with Smed-betacatenin1, but not Smed-betacatenin2, these data suggest that S. mediterranea beta-catenins could be functionally specialized and that only Smed-betacatenin1 is involved in Wnt signalling. PMID:18287199

  14. Inferring regulatory networks from experimental morphological phenotypes: a computational method reverse-engineers planarian regeneration.

    PubMed

    Lobo, Daniel; Levin, Michael

    2015-06-01

    Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method provides an automated

  15. Elucidating the phylogenetic position of Gnathostomulida and first mitochondrial genomes of Gnathostomulida, Gastrotricha and Polycladida (Platyhelminthes).

    PubMed

    Golombek, Anja; Tobergte, Sarah; Struck, Torsten H

    2015-05-01

    Gnathostomulida is a taxon of small marine worms, which exclusively inhabit the interstitium. The evolution of Gnathostomulida has been discussed for decades. Originally regarded as primitive animals with affinities to flatworms, the phylogenetic position of Gnathostomulida has been debated. Given the lack of an anus a close relationship to Platyhelminthes has been maintained (i.e., Plathelminthomorpha hypothesis). Alternative hypotheses proposed Gnathostomulida as being close to Gastrotricha due to the presence of a monociliary epidermis (i.e., Monokonta/Neotrichozoa hypothesis) or to Syndermata based on the complicated jaw apparatus (i.e., Gnathifera hypothesis). Molecular analyses using only few genes were inconclusive. Recent phylogenomic studies brought some progress by placing Gnathostomulida as sister to Syndermata, but support for this relationship was low and depended on the analytical strategy. Herein we present the first data of complete or nearly complete mitochondrial genomes for two gnathostomulids (Gnathostomula paradoxa &G. armata), one gastrotrich (Lepidodermella squamata) and one polyclad flatworm (Stylochoplana maculata) to address the uncertain phylogenetic affinity of Gnathostomulida. Our analyses found Gnathostomulida as sister to Syndermata (Gnathifera hypothesis). Thorough sensitivity analyses addressing taxon instability, branch length heterogeneity (also known as long branch attraction) and base composition heterogeneity showed that the position of Gnathostomulida is consistent across the different analyses and, hence, independent of potential misleading biases. Moreover, by ameliorating these different biases nodal support values could be increased to maximum values. Thus, our data support the hypothesis that the different jaw apparatuses of Syndermata and Gnathostomulida are indeed homologous structures as proposed by the Gnathifera hypothesis. PMID:25796325

  16. NF-YB Regulates Spermatogonial Stem Cell Self-Renewal and Proliferation in the Planarian Schmidtea mediterranea.

    PubMed

    Iyer, Harini; Collins, James J; Newmark, Phillip A

    2016-06-01

    Gametes are the source and carrier of genetic information, essential for the propagation of all sexually reproducing organisms. Male gametes are derived from a progenitor stem cell population called spermatogonial stem cells (SSCs). SSCs give rise to male gametes through the coordination of two essential processes: self-renewal to produce more SSCs, and differentiation to produce mature sperm. Disruption of this equilibrium can lead to excessive proliferation of SSCs, causing tumorigenesis, or can result in aberrant differentiation, leading to infertility. Little is known about how SSCs achieve the fine balance between self-renewal and differentiation, which is necessary for their remarkable output and developmental potential. To understand the mechanisms of SSC maintenance, we examine the planarian homolog of Nuclear Factor Y-B (NF-YB), which is required for the maintenance of early planarian male germ cells. Here, we demonstrate that NF-YB plays a role in the self-renewal and proliferation of planarian SSCs, but not in their specification or differentiation. Furthermore, we characterize members of the NF-Y complex in Schistosoma mansoni, a parasitic flatworm related to the free-living planarian. We find that the function of NF-YB in regulating male germ cell proliferation is conserved in schistosomes. This finding is especially significant because fecundity is the cause of pathogenesis of S. mansoni. Our findings can help elucidate the complex relationship between self-renewal and differentiation of SSCs, and may also have implications for understanding and controlling schistosomiasis. PMID:27304889

  17. NF-YB Regulates Spermatogonial Stem Cell Self-Renewal and Proliferation in the Planarian Schmidtea mediterranea

    PubMed Central

    Iyer, Harini; Collins, James J.; Newmark, Phillip A.

    2016-01-01

    Gametes are the source and carrier of genetic information, essential for the propagation of all sexually reproducing organisms. Male gametes are derived from a progenitor stem cell population called spermatogonial stem cells (SSCs). SSCs give rise to male gametes through the coordination of two essential processes: self-renewal to produce more SSCs, and differentiation to produce mature sperm. Disruption of this equilibrium can lead to excessive proliferation of SSCs, causing tumorigenesis, or can result in aberrant differentiation, leading to infertility. Little is known about how SSCs achieve the fine balance between self-renewal and differentiation, which is necessary for their remarkable output and developmental potential. To understand the mechanisms of SSC maintenance, we examine the planarian homolog of Nuclear Factor Y-B (NF-YB), which is required for the maintenance of early planarian male germ cells. Here, we demonstrate that NF-YB plays a role in the self-renewal and proliferation of planarian SSCs, but not in their specification or differentiation. Furthermore, we characterize members of the NF-Y complex in Schistosoma mansoni, a parasitic flatworm related to the free-living planarian. We find that the function of NF-YB in regulating male germ cell proliferation is conserved in schistosomes. This finding is especially significant because fecundity is the cause of pathogenesis of S. mansoni. Our findings can help elucidate the complex relationship between self-renewal and differentiation of SSCs, and may also have implications for understanding and controlling schistosomiasis. PMID:27304889

  18. The BMP pathway is essential for re-specification and maintenance of the dorsoventral axis in regenerating and intact planarians.

    PubMed

    Molina, M Dolores; Saló, Emili; Cebrià, Francesc

    2007-11-01

    The bone morphogenetic protein (BMP) pathway has been shown to play an important role in the establishment of the dorsoventral axis during development in both vertebrate and invertebrate species. In an attempt to unravel the role of BMPs in pattern formation during planarian regeneration, we studied this signaling pathway in Schmidtea mediterranea. Here, we functionally characterize planarian homologues of two key elements of the pathway: Smed-BMP and Smed-Smad1. Whole-mount in situ hybridization showed that Smed-BMP is expressed at the planarian dorsal midline, suggesting a role in dorsoventral patterning, while Smed-Smad1 is widely expressed throughout the mesenchyme and in the central nervous system. RNA interference (RNAi) knockdowns of Smed-BMP or Smed-Smad1 led to the disappearance of dorsal markers along with the ectopic expression of ventral markers on the dorsal side of the treated animals. In almost all cases, a duplicated central nervous system differentiated dorsally after Smed-BMP or Smed-Smad1 RNAi. These defects were observed not only during regeneration but also in intact non-regenerating animals. Our results suggest that the BMP signaling pathway is conserved in planarians and that it plays a key role in the regeneration and maintenance of the dorsoventral axis. PMID:17905225

  19. Size Matters!. Birth Size and a Size-Independent Stochastic Term Determine Asexual Reproduction Dynamics in Freshwater Planarians

    NASA Astrophysics Data System (ADS)

    Thomas, Michael A.; Quinodoz, Sofia; Schötz, Eva-Maria

    2012-09-01

    Asexual reproduction by division in higher organisms is rare, because a prerequisite is the ability to regenerate an entire organism from a piece of the original body. Freshwater planarians are one of the few animals that can reproduce this way, but little is known about the regulation of their reproduction cycles or strategies. We have previously shown that a planarian's reproduction strategy is randomized to include fragmentations, producing multiple offspring, as well as binary fissions, and can be partially explained by a maximum relative entropy principle. In this study we attempt to decompose the factors controlling their reproduction cycle. Based on recent studies on the cell cycle of budding yeast, which suggest that molecular noise in gene expression and cell size at birth together control cell cycle variability, we investigated whether the variability in planarian reproduction waiting times could be similarly regulated. We find that such a model can indeed explain the observed distribution of waiting times between birth and next reproductive event, suggesting that birth size and a stochastic noise term govern the reproduction dynamics of asexual planarians.

  20. Genetic regulators of a pluripotent adult stem cell system in planarians identified by RNAi and clonal analysis

    PubMed Central

    Wagner, Daniel E.; Ho, Jaclyn J.

    2012-01-01

    Summary Pluripotency is a central, well-studied feature of embryonic development, but the role of pluripotent cell regulation in somatic tissue regeneration remains poorly understood. In planarians, regeneration of entire animals from tissue fragments is promoted by the activity of adult pluripotent stem cells (cNeoblasts). We utilized transcriptional profiling to identify planarian genes expressed in adult proliferating, regenerative cells (neoblasts). We also developed quantitative clonal analysis methods for expansion and differentiation of cNeoblast descendants that, together with RNAi, revealed gene roles in stem cell biology. Genes encoding two zinc finger proteins, Vasa, a LIM domain protein, Sox and Jun-like transcription factors, two candidate RNA-binding proteins, a Setd8-like protein, and PRC2 (Polycomb) were required for proliferative expansion and/or differentiation of cNeoblast-derived clones. These findings suggest that planarian stem cells utilize molecular mechanisms found in germ cells and other pluripotent cell types, and identify novel genetic regulators of the planarian stem cell system. PMID:22385657

  1. Analysis of Stem Cell Motility In Vivo Based on Immunodetection of Planarian Neoblasts and Tracing of BrdU-Labeled Cells After Partial Irradiation.

    PubMed

    Tasaki, Junichi; Uchiyama-Tasaki, Chihiro; Rouhana, Labib

    2016-01-01

    Planarian flatworms have become an important system for the study of stem cell behavior and regulation in vivo. These organisms are able to regenerate any part of their body upon damage or amputation. A crucial cellular event in the process of planarian regeneration is the migration of pluripotent stem cells (known as neoblasts) to the site of injury. Here we describe two approaches for analyzing migration of planarian stem cells to an area where these have been ablated by localized X-ray irradiation. The first approach involves immunolabeling of mitotic neoblasts, while the second is based on tracing stem cells and their progeny after BrdU incorporation. The use of planarians in studies of cell motility is suitable for the identification of factors that influence stem cell migration in vivo and is amenable to RNA interference or pharmacological screening. PMID:26498794

  2. Defining the molecular profile of planarian pluripotent stem cells using a combinatorial RNA-seq, RNA interference and irradiation approach

    PubMed Central

    2012-01-01

    Background Planarian stem cells, or neoblasts, drive the almost unlimited regeneration capacities of freshwater planarians. Neoblasts are traditionally described by their morphological features and by the fact that they are the only proliferative cell type in asexual planarians. Therefore, they can be specifically eliminated by irradiation. Irradiation, however, is likely to induce transcriptome-wide changes in gene expression that are not associated with neoblast ablation. This has affected the accurate description of their specific transcriptomic profile. Results We introduce the use of Smed-histone-2B RNA interference (RNAi) for genetic ablation of neoblast cells in Schmidtea mediterranea as an alternative to irradiation. We characterize the rapid, neoblast-specific phenotype induced by Smed-histone-2B RNAi, resulting in neoblast ablation. We compare and triangulate RNA-seq data after using both irradiation and Smed-histone-2B RNAi over a time course as means of neoblast ablation. Our analyses show that Smed-histone-2B RNAi eliminates neoblast gene expression with high specificity and discrimination from gene expression in other cellular compartments. We compile a high confidence list of genes downregulated by both irradiation and Smed-histone-2B RNAi and validate their expression in neoblast cells. Lastly, we analyze the overall expression profile of neoblast cells. Conclusions Our list of neoblast genes parallels their morphological features and is highly enriched for nuclear components, chromatin remodeling factors, RNA splicing factors, RNA granule components and the machinery of cell division. Our data reveal that the regulation of planarian stem cells relies on posttranscriptional regulatory mechanisms and suggest that planarians are an ideal model for this understudied aspect of stem cell biology. PMID:22439894

  3. COE loss-of-function analysis reveals a genetic program underlying maintenance and regeneration of the nervous system in planarians.

    PubMed

    Cowles, Martis W; Omuro, Kerilyn C; Stanley, Brianna N; Quintanilla, Carlo G; Zayas, Ricardo M

    2014-10-01

    Members of the COE family of transcription factors are required for central nervous system (CNS) development. However, the function of COE in the post-embryonic CNS remains largely unknown. An excellent model for investigating gene function in the adult CNS is the freshwater planarian. This animal is capable of regenerating neurons from an adult pluripotent stem cell population and regaining normal function. We previously showed that planarian coe is expressed in differentiating and mature neurons and that its function is required for proper CNS regeneration. Here, we show that coe is essential to maintain nervous system architecture and patterning in intact (uninjured) planarians. We took advantage of the robust phenotype in intact animals to investigate the genetic programs coe regulates in the CNS. We compared the transcriptional profiles of control and coe RNAi planarians using RNA sequencing and identified approximately 900 differentially expressed genes in coe knockdown animals, including 397 downregulated genes that were enriched for nervous system functional annotations. Next, we validated a subset of the downregulated transcripts by analyzing their expression in coe-deficient planarians and testing if the mRNAs could be detected in coe+ cells. These experiments revealed novel candidate targets of coe in the CNS such as ion channel, neuropeptide, and neurotransmitter genes. Finally, to determine if loss of any of the validated transcripts underscores the coe knockdown phenotype, we knocked down their expression by RNAi and uncovered a set of coe-regulated genes implicated in CNS regeneration and patterning, including orthologs of sodium channel alpha-subunit and pou4. Our study broadens the knowledge of gene expression programs regulated by COE that are required for maintenance of neural subtypes and nervous system architecture in adult animals. PMID:25356635

  4. Early planarian brain regeneration is independent of blastema polarity mediated by the Wnt/β-catenin pathway.

    PubMed

    Iglesias, Marta; Almuedo-Castillo, Maria; Aboobaker, A Aziz; Saló, Emili

    2011-10-01

    Analysis of anteroposterior (AP) axis specification in regenerating planarian flatworms has shown that Wnt/β-catenin signaling is required for posterior specification and that the FGF-like receptor molecule nou-darake (ndk) may be involved in restricting brain regeneration to anterior regions. The relationship between re-establishment of AP identity and correct morphogenesis of the brain is, however, still poorly understood. Here we report the characterization of two axin paralogs in the planarian Schmidtea mediterranea. Although Axins are well known negative regulators of Wnt/β-catenin signaling, no role in AP specification has previously been reported for axin genes in planarians. We show that silencing of Smed-axin genes by RNA interference (RNAi) results in two-tailed planarians, a phenotype previously reported after silencing of Smed-APC-1, another β-catenin inhibitor. More strikingly, we show for the first time that while early brain formation at anterior wounds remains unaffected, subsequent development of the brain is blocked in the two-tailed planarians generated after silencing of Smed-axin genes and Smed-APC-1. These findings suggest that the mechanisms underlying early brain formation can be uncoupled from the specification of AP identity by the Wnt/β-catenin pathway. Finally, the posterior expansion of the brain observed following Smed-ndk RNAi is enhanced by silencing Smed-APC-1, revealing an indirect relationship between the FGFR/Ndk and Wnt/β-catenin signaling systems in establishing the posterior limits of brain differentiation. PMID:21806978

  5. COE Loss-of-Function Analysis Reveals a Genetic Program Underlying Maintenance and Regeneration of the Nervous System in Planarians

    PubMed Central

    Cowles, Martis W.; Omuro, Kerilyn C.; Stanley, Brianna N.; Quintanilla, Carlo G.; Zayas, Ricardo M.

    2014-01-01

    Members of the COE family of transcription factors are required for central nervous system (CNS) development. However, the function of COE in the post-embryonic CNS remains largely unknown. An excellent model for investigating gene function in the adult CNS is the freshwater planarian. This animal is capable of regenerating neurons from an adult pluripotent stem cell population and regaining normal function. We previously showed that planarian coe is expressed in differentiating and mature neurons and that its function is required for proper CNS regeneration. Here, we show that coe is essential to maintain nervous system architecture and patterning in intact (uninjured) planarians. We took advantage of the robust phenotype in intact animals to investigate the genetic programs coe regulates in the CNS. We compared the transcriptional profiles of control and coe RNAi planarians using RNA sequencing and identified approximately 900 differentially expressed genes in coe knockdown animals, including 397 downregulated genes that were enriched for nervous system functional annotations. Next, we validated a subset of the downregulated transcripts by analyzing their expression in coe-deficient planarians and testing if the mRNAs could be detected in coe+ cells. These experiments revealed novel candidate targets of coe in the CNS such as ion channel, neuropeptide, and neurotransmitter genes. Finally, to determine if loss of any of the validated transcripts underscores the coe knockdown phenotype, we knocked down their expression by RNAi and uncovered a set of coe-regulated genes implicated in CNS regeneration and patterning, including orthologs of sodium channel alpha-subunit and pou4. Our study broadens the knowledge of gene expression programs regulated by COE that are required for maintenance of neural subtypes and nervous system architecture in adult animals. PMID:25356635

  6. PBX/extradenticle is required to re-establish axial structures and polarity during planarian regeneration

    PubMed Central

    Blassberg, Robert A.; Felix, Daniel A.; Tejada-Romero, Belen; Aboobaker, A. Aziz

    2013-01-01

    Recent advances in a number of systems suggest many genes involved in orchestrating regeneration are redeployed from similar processes in development, with others being novel to the regeneration process in particular lineages. Of particular importance will be understanding the architecture of regenerative genetic regulatory networks and whether they are conserved across broad phylogenetic distances. Here, we describe the role of the conserved TALE class protein PBX/Extradenticle in planarians, a representative member of the Lophotrocozoa. PBX/Extradenticle proteins play central roles in both embryonic and post-embryonic developmental patterning in both vertebrates and insects, and we demonstrate a broad requirement during planarian regeneration. We observe that Smed-pbx has pleiotropic functions during regeneration, with a primary role in patterning the anterior-posterior (AP) axis and AP polarity. Smed-pbx is required for expression of polarity determinants notum and wnt1 and for correct patterning of the structures polarized along the AP axis, such as the brain, pharynx and gut. Overall, our data suggest that Smed-pbx functions as a central integrator of positional information to drive patterning of regeneration along the body axis. PMID:23318635

  7. The NuRD complex component p66 suppresses photoreceptor neuron regeneration in planarians

    PubMed Central

    Vásquez‐Doorman, Constanza

    2016-01-01

    Abstract Regeneration involves precise control of cell fate to produce an appropriate complement of tissues formed within a blastema. Several chromatin‐modifying complexes have been identified as required for regeneration in planarians, but it is unclear whether this class of molecules uniformly promotes the production of differentiated cells. We identify a function for p66, encoding a DNA‐binding protein component of the NuRD (nucleosome remodeling and deacetylase) complex, as well as the chromodomain helicase chd4, in suppressing production of photoreceptor neurons (PRNs) in planarians. This suppressive effect appeared restricted to PRNs because p66 inhibition did not influence numbers of eye pigment cup cells (PCCs) and decreased numbers of brain neurons and epidermal progenitors. PRNs from p66(RNAi) animals differentiated with some abnormalities but nonetheless produced arrestin+ projections to the brain. p66 inhibition produced excess ovo+otxA+ PRN progenitors without affecting numbers of ovo+otxA− PCC progenitors, and ovo and otxA were each required for the p66(RNAi) excess PRN phenotype. Together these results suggest that p66 acts through the NuRD complex to suppress PRN production by limiting expression of lineage‐specific transcription factors. PMID:27606067

  8. Light-induced depigmentation in planarians models the pathophysiology of acute porphyrias

    PubMed Central

    Stubenhaus, Bradford M; Dustin, John P; Neverett, Emily R; Beaudry, Megan S; Nadeau, Leanna E; Burk-McCoy, Ethan; He, Xinwen; Pearson, Bret J; Pellettieri, Jason

    2016-01-01

    Porphyrias are disorders of heme metabolism frequently characterized by extreme photosensitivity. This symptom results from accumulation of porphyrins, tetrapyrrole intermediates in heme biosynthesis that generate reactive oxygen species when exposed to light, in the skin of affected individuals. Here we report that in addition to producing an ommochrome body pigment, the planarian flatworm Schmidtea mediterranea generates porphyrins in its subepithelial pigment cells under physiological conditions, and that this leads to pigment cell loss when animals are exposed to intense visible light. Remarkably, porphyrin biosynthesis and light-induced depigmentation are enhanced by starvation, recapitulating a common feature of some porphyrias – decreased nutrient intake precipitates an acute manifestation of the disease. Our results establish planarians as an experimentally tractable animal model for research into the pathophysiology of acute porphyrias, and potentially for the identification of novel pharmacological interventions capable of alleviating porphyrin-mediated photosensitivity or decoupling dieting and fasting from disease pathogenesis. DOI: http://dx.doi.org/10.7554/eLife.14175.001 PMID:27240733

  9. Evolution of the EGFR pathway in Metazoa and its diversification in the planarian Schmidtea mediterranea.

    PubMed

    Barberán, Sara; Martín-Durán, José M; Cebrià, Francesc

    2016-01-01

    The EGFR pathway is an essential signaling system in animals, whose core components are the epidermal growth factors (EGF ligands) and their trans-membrane tyrosine kinase receptors (EGFRs). Despite extensive knowledge in classical model organisms, little is known of the composition and function of the EGFR pathway in most animal lineages. Here, we have performed an extensive search for the presence of EGFRs and EGF ligands in representative species of most major animal clades, with special focus on the planarian Schmidtea mediterranea. With the exception of placozoans and cnidarians, we found that the EGFR pathway is potentially present in all other analyzed animal groups, and has experienced frequent independent expansions. We further characterized the expression domains of the EGFR/EGF identified in S. mediterranea, revealing a wide variety of patterns and localization in almost all planarian tissues. Finally, functional experiments suggest an interaction between one of the previously described receptors, Smed-egfr-5, and the newly found ligand Smed-egf-6. Our findings provide the most comprehensive overview to date of the EGFR pathway, and indicate that the last common metazoan ancestor had an initial complement of one EGFR and one putative EGF ligand, which was often expanded or lost during animal evolution. PMID:27325311

  10. A mex3 homolog is required for differentiation during planarian stem cell lineage development

    PubMed Central

    Zhu, Shu Jun; Hallows, Stephanie E; Currie, Ko W; Xu, ChangJiang; Pearson, Bret J

    2015-01-01

    Neoblasts are adult stem cells (ASCs) in planarians that sustain cell replacement during homeostasis and regeneration of any missing tissue. While numerous studies have examined genes underlying neoblast pluripotency, molecular pathways driving postmitotic fates remain poorly defined. In this study, we used transcriptional profiling of irradiation-sensitive and irradiation-insensitive cell populations and RNA interference (RNAi) functional screening to uncover markers and regulators of postmitotic progeny. We identified 32 new markers distinguishing two main epithelial progenitor populations and a planarian homolog to the MEX3 RNA-binding protein (Smed-mex3-1) as a key regulator of lineage progression. mex3-1 was required for generating differentiated cells of multiple lineages, while restricting the size of the stem cell compartment. We also demonstrated the utility of using mex3-1(RNAi) animals to identify additional progenitor markers. These results identified mex3-1 as a cell fate regulator, broadly required for differentiation, and suggest that mex3-1 helps to mediate the balance between ASC self-renewal and commitment. DOI: http://dx.doi.org/10.7554/eLife.07025.001 PMID:26114597

  11. Dishevelled is essential for neural connectivity and planar cell polarity in planarians.

    PubMed

    Almuedo-Castillo, Maria; Saló, Emili; Adell, Teresa

    2011-02-15

    The Wingless/Integrated (Wnt) signaling pathway controls multiple events during development and homeostasis. It comprises multiple branches, mainly classified according to their dependence on β-catenin activation. The Wnt/β-catenin branch is essential for the establishment of the embryonic anteroposterior (AP) body axis throughout the phylogenetic tree. It is also required for AP axis establishment during planarian regeneration. Wnt/β-catenin-independent signaling encompasses several different pathways, of which the most extensively studied is the planar cell polarity (PCP) pathway, which is responsible for planar polarization of cell structures within an epithelial sheet. Dishevelled (Dvl) is the hub of Wnt signaling because it regulates and channels the Wnt signal into every branch. Here, we analyze the role of Schmidtea mediterranea Dvl homologs (Smed-dvl-1 and Smed-dvl-2) using gene silencing. We demonstrate that in addition to a role in AP axis specification, planarian Dvls are involved in at least two different β-catenin-independent processes. First, they are essential for neural connectivity through Smed-wnt5 signaling. Second, Smed-dvl-2, together with the S. mediterranea homologs of Van-Gogh (Vang) and Diversin (Div), is required for apical positioning of the basal bodies of epithelial cells. These data represent evidence not only of the function of the PCP network in lophotrocozoans but of the involvement of the PCP core elements Vang and Div in apical positioning of the cilia. PMID:21282632

  12. Morphogenesis defects are associated with abnormal nervous system regeneration following roboA RNAi in planarians.

    PubMed

    Cebrià, Francesc; Newmark, Phillip A

    2007-03-01

    The process by which the proper pattern is restored to newly formed tissues during metazoan regeneration remains an open question. Here, we provide evidence that the nervous system plays a role in regulating morphogenesis during anterior regeneration in the planarian Schmidtea mediterranea. RNA interference (RNAi) knockdown of a planarian ortholog of the axon-guidance receptor roundabout (robo) leads to unexpected phenotypes during anterior regeneration, including the development of a supernumerary pharynx (the feeding organ of the animal) and the production of ectopic, dorsal outgrowths with cephalic identity. We show that Smed-roboA RNAi knockdown disrupts nervous system structure during cephalic regeneration: the newly regenerated brain and ventral nerve cords do not re-establish proper connections. These neural defects precede, and are correlated with, the development of ectopic structures. We propose that, in the absence of proper connectivity between the cephalic ganglia and the ventral nerve cords, neurally derived signals promote the differentiation of pharyngeal and cephalic structures. Together with previous studies on regeneration in annelids and amphibians, these results suggest a conserved role of the nervous system in pattern formation during blastema-based regeneration. PMID:17251262

  13. A lophotrochozoan-specific nuclear hormone receptor is required for reproductive system development in the planarian

    PubMed Central

    Tharp, Marla E.; Collins, James J.; Newmark, Phillip A.

    2014-01-01

    Germ cells of sexually reproducing organisms receive an array of cues from somatic tissues that instruct developmental processes. Although the nature of these signals differs amongst organisms, the importance of germline-soma interactions is a common theme. Recently, peptide hormones from the nervous system have been shown to regulate germ cell development in the planarian Schmidtea mediterranea; thus, we sought to investigate a second class of hormones with a conserved role in reproduction, the lipophilic hormones. In order to study these signals, we identified a set of putative lipophilic hormone receptors, known as nuclear hormone receptors, and analyzed their functions in reproductive development. We found one gene, nhr-1, belonging to a small class of functionally uncharacterized lophotrochozoan-specific receptors, to be essential for the development of differentiated germ cells. Upon nhr-1 knockdown, germ cells in the testes and ovaries fail to mature, and remain as undifferentiated germline stem cells. Further analysis revealed that nhr-1 mRNA is expressed in the accessory reproductive organs and is required for their development, suggesting that this transcription factor functions cell non-autonomously in regulating germ cell development. Our studies identify a role for nuclear hormone receptors in planarian reproductive maturation and reinforce the significance of germline-soma interactions in sexual reproduction across metazoans. PMID:25278423

  14. A mex3 homolog is required for differentiation during planarian stem cell lineage development.

    PubMed

    Zhu, Shu Jun; Hallows, Stephanie E; Currie, Ko W; Xu, ChangJiang; Pearson, Bret J

    2015-01-01

    Neoblasts are adult stem cells (ASCs) in planarians that sustain cell replacement during homeostasis and regeneration of any missing tissue. While numerous studies have examined genes underlying neoblast pluripotency, molecular pathways driving postmitotic fates remain poorly defined. In this study, we used transcriptional profiling of irradiation-sensitive and irradiation-insensitive cell populations and RNA interference (RNAi) functional screening to uncover markers and regulators of postmitotic progeny. We identified 32 new markers distinguishing two main epithelial progenitor populations and a planarian homolog to the MEX3 RNA-binding protein (Smed-mex3-1) as a key regulator of lineage progression. mex3-1 was required for generating differentiated cells of multiple lineages, while restricting the size of the stem cell compartment. We also demonstrated the utility of using mex3-1(RNAi) animals to identify additional progenitor markers. These results identified mex3-1 as a cell fate regulator, broadly required for differentiation, and suggest that mex3-1 helps to mediate the balance between ASC self-renewal and commitment. PMID:26114597

  15. TOR signaling regulates planarian stem cells and controls localized and organismal growth.

    PubMed

    Peiris, T Harshani; Weckerle, Frank; Ozamoto, Elyse; Ramirez, Daniel; Davidian, Devon; García-Ojeda, Marcos E; Oviedo, Néstor J

    2012-04-01

    Target of Rapamycin (TOR) controls an evolutionarily conserved signaling pathway that modulates cellular growth and division by sensing levels of nutrients, energy and stress. As such, TOR signaling is a crucial component of tissues and organs that translates systemic signals into cellular behavior. The ubiquitous nature of TOR signaling, together with the difficulty of analyzing tissue during cellular turnover and repair, have limited our understanding of how this kinase operates throughout the body. Here, we use the planarian model system to address TOR regulation at the organismal level. The planarian TOR homolog (Smed-TOR) is ubiquitously expressed, including stem cells (neoblasts) and differentiated tissues. Inhibition of TOR with RNA interference severely restricts cell proliferation, allowing the study of neoblasts with restricted proliferative capacity during regeneration and systemic cell turnover. Strikingly, TOR signaling is required for neoblast response to amputation and localized growth (blastema). However, in the absence of TOR signaling, regeneration takes place only within differentiated tissues. In addition, TOR is essential for maintaining the balance between cell division and cell death, and its dysfunction leads to tissue degeneration and lack of organismal growth in the presence of nutrients. Finally, TOR function is likely to be mediated through TOR Complex 1 as its disruption recapitulates signs of the TOR phenotype. Our data reveal novel roles for TOR signaling in controlling adult stem cells at a systemic level and suggest a new paradigm for studying TOR function during physiological turnover and regeneration. PMID:22427692

  16. PBX/extradenticle is required to re-establish axial structures and polarity during planarian regeneration.

    PubMed

    Blassberg, Robert A; Felix, Daniel A; Tejada-Romero, Belen; Aboobaker, A Aziz

    2013-02-01

    Recent advances in a number of systems suggest many genes involved in orchestrating regeneration are redeployed from similar processes in development, with others being novel to the regeneration process in particular lineages. Of particular importance will be understanding the architecture of regenerative genetic regulatory networks and whether they are conserved across broad phylogenetic distances. Here, we describe the role of the conserved TALE class protein PBX/Extradenticle in planarians, a representative member of the Lophotrocozoa. PBX/Extradenticle proteins play central roles in both embryonic and post-embryonic developmental patterning in both vertebrates and insects, and we demonstrate a broad requirement during planarian regeneration. We observe that Smed-pbx has pleiotropic functions during regeneration, with a primary role in patterning the anterior-posterior (AP) axis and AP polarity. Smed-pbx is required for expression of polarity determinants notum and wnt1 and for correct patterning of the structures polarized along the AP axis, such as the brain, pharynx and gut. Overall, our data suggest that Smed-pbx functions as a central integrator of positional information to drive patterning of regeneration along the body axis. PMID:23318635

  17. Egf Signaling Directs Neoblast Repopulation by Regulating Asymmetric Cell Division in Planarians.

    PubMed

    Lei, Kai; Thi-Kim Vu, Hanh; Mohan, Ryan D; McKinney, Sean A; Seidel, Chris W; Alexander, Richard; Gotting, Kirsten; Workman, Jerry L; Sánchez Alvarado, Alejandro

    2016-08-22

    A large population of proliferative stem cells (neoblasts) is required for physiological tissue homeostasis and post-injury regeneration in planarians. Recent studies indicate that survival of a few neoblasts after sublethal irradiation results in the clonal expansion of the surviving stem cells and the eventual restoration of tissue homeostasis and regenerative capacity. However, the precise mechanisms regulating the population dynamics of neoblasts remain largely unknown. Here, we uncovered a central role for epidermal growth factor (EGF) signaling during in vivo neoblast expansion mediated by Smed-egfr-3 (egfr-3) and its putative ligand Smed-neuregulin-7 (nrg-7). Furthermore, the EGF receptor-3 protein localizes asymmetrically on the cytoplasmic membrane of neoblasts, and the ratio of asymmetric to symmetric cell divisions decreases significantly in egfr-3(RNAi) worms. Our results not only provide the first molecular evidence of asymmetric stem cell divisions in planarians, but also demonstrate that EGF signaling likely functions as an essential regulator of neoblast clonal expansion. PMID:27523733

  18. Evolution of the EGFR pathway in Metazoa and its diversification in the planarian Schmidtea mediterranea

    PubMed Central

    Barberán, Sara; Martín-Durán, José M.; Cebrià, Francesc

    2016-01-01

    The EGFR pathway is an essential signaling system in animals, whose core components are the epidermal growth factors (EGF ligands) and their trans-membrane tyrosine kinase receptors (EGFRs). Despite extensive knowledge in classical model organisms, little is known of the composition and function of the EGFR pathway in most animal lineages. Here, we have performed an extensive search for the presence of EGFRs and EGF ligands in representative species of most major animal clades, with special focus on the planarian Schmidtea mediterranea. With the exception of placozoans and cnidarians, we found that the EGFR pathway is potentially present in all other analyzed animal groups, and has experienced frequent independent expansions. We further characterized the expression domains of the EGFR/EGF identified in S. mediterranea, revealing a wide variety of patterns and localization in almost all planarian tissues. Finally, functional experiments suggest an interaction between one of the previously described receptors, Smed-egfr-5, and the newly found ligand Smed-egf-6. Our findings provide the most comprehensive overview to date of the EGFR pathway, and indicate that the last common metazoan ancestor had an initial complement of one EGFR and one putative EGF ligand, which was often expanded or lost during animal evolution. PMID:27325311

  19. Identification and expression analysis of a Spsb gene in planarian Dugesia japonica.

    PubMed

    Dong, Zimei; Cheng, Fangfang; Yuwen, Yanqing; Chen, Jing; Li, Xiaoyan; Dou, He; Zhang, Haixia; Chen, Guangwen; Liu, Dezeng

    2015-06-15

    The SPSB family is comprised of four highly conserved proteins, each containing a C-terminal SOCS box motif and a central SPRY domain. Presently, Spsb genes have been found in mammals and in a few invertebrates, however, the specific functions of these genes are still unknown. In this study, we identified a Spsb gene from the planarian Dugesia japonica and termed it DjSpsb. The temporal and spatial expression patterns of DjSpsb were examined in both intact and regenerative animals, and expression levels were also quantified in response to various stressors. The results show that (1) DjSpsb is highly conserved in evolutionary history in metazoans and is at closer relationship to Spsb1, Spsb2 and Spsb4; (2) DjSpsb mRNA is mainly expressed in the head and also throughout head regeneration processes, particularly, its expression up-regulated observably on day 5 after amputation; (3) DjSpsb is also expressed in the testes and yolk glands; (4) DjSpsb expression is induced by high temperature and ethanol but inhibited by high doses of ionic liquids. The date suggests that the DjSpsb gene might be active in central nervous system (CNS) formation and functional recovery during head regeneration, and it is also involved in the development of germ cells and stress responses in the planarians. PMID:25827717

  20. The NuRD complex component p66 suppresses photoreceptor neuron regeneration in planarians.

    PubMed

    Vásquez-Doorman, Constanza; Petersen, Christian P

    2016-06-01

    Regeneration involves precise control of cell fate to produce an appropriate complement of tissues formed within a blastema. Several chromatin-modifying complexes have been identified as required for regeneration in planarians, but it is unclear whether this class of molecules uniformly promotes the production of differentiated cells. We identify a function for p66, encoding a DNA-binding protein component of the NuRD (nucleosome remodeling and deacetylase) complex, as well as the chromodomain helicase chd4, in suppressing production of photoreceptor neurons (PRNs) in planarians. This suppressive effect appeared restricted to PRNs because p66 inhibition did not influence numbers of eye pigment cup cells (PCCs) and decreased numbers of brain neurons and epidermal progenitors. PRNs from p66(RNAi) animals differentiated with some abnormalities but nonetheless produced arrestin+ projections to the brain. p66 inhibition produced excess ovo+otxA+ PRN progenitors without affecting numbers of ovo+otxA- PCC progenitors, and ovo and otxA were each required for the p66(RNAi) excess PRN phenotype. Together these results suggest that p66 acts through the NuRD complex to suppress PRN production by limiting expression of lineage-specific transcription factors. PMID:27606067

  1. Proteomic profiling of the planarian Schmidtea mediterranea and its mucous reveals similarities with human secretions and those predicted for parasitic flatworms.

    PubMed

    Bocchinfuso, Donald G; Taylor, Paul; Ross, Eric; Ignatchenko, Alex; Ignatchenko, Vladimir; Kislinger, Thomas; Pearson, Bret J; Moran, Michael F

    2012-09-01

    The freshwater planarian Schmidtea mediterranea has been used in research for over 100 years, and is an emerging stem cell model because of its capability of regenerating large portions of missing body parts. Exteriorly, planarians are covered in mucous secretions of unknown composition, implicated in locomotion, predation, innate immunity, and substrate adhesion. Although the planarian genome has been sequenced, it remains mostly unannotated, challenging both genomic and proteomic analyses. The goal of the current study was to annotate the proteome of the whole planarian and its mucous fraction. The S. mediterranea proteome was analyzed via mass spectrometry by using multidimensional protein identification technology with whole-worm tryptic digests. By using a proteogenomics approach, MS data were searched against an in silico translated planarian transcript database, and by using the Swiss-Prot BLAST algorithm to identify proteins similar to planarian queries. A total of 1604 proteins were identified. The mucous subproteome was defined through analysis of a mucous trail fraction and an extract obtained by treating whole worms with the mucolytic agent N-acetylcysteine. Gene Ontology analysis confirmed that the mucous fractions were enriched with secreted proteins. The S. mediterranea proteome is highly similar to that predicted for the trematode Schistosoma mansoni associated with intestinal schistosomiasis, with the mucous subproteome particularly highly conserved. Remarkably, orthologs of 119 planarian mucous proteins are present in human mucosal secretions and tear fluid. We suggest planarians have potential to be a model system for the characterization of mucous protein function and relevant to parasitic flatworm infections and diseases underlined by mucous aberrancies, such as cystic fibrosis, asthma, and other lung diseases. PMID:22653920

  2. Proteomic Profiling of the Planarian Schmidtea mediterranea and Its Mucous Reveals Similarities with Human Secretions and Those Predicted for Parasitic Flatworms*

    PubMed Central

    Bocchinfuso, Donald G.; Taylor, Paul; Ross, Eric; Ignatchenko, Alex; Ignatchenko, Vladimir; Kislinger, Thomas; Pearson, Bret J.; Moran, Michael F.

    2012-01-01

    The freshwater planarian Schmidtea mediterranea has been used in research for over 100 years, and is an emerging stem cell model because of its capability of regenerating large portions of missing body parts. Exteriorly, planarians are covered in mucous secretions of unknown composition, implicated in locomotion, predation, innate immunity, and substrate adhesion. Although the planarian genome has been sequenced, it remains mostly unannotated, challenging both genomic and proteomic analyses. The goal of the current study was to annotate the proteome of the whole planarian and its mucous fraction. The S. mediterranea proteome was analyzed via mass spectrometry by using multidimensional protein identification technology with whole-worm tryptic digests. By using a proteogenomics approach, MS data were searched against an in silico translated planarian transcript database, and by using the Swiss-Prot BLAST algorithm to identify proteins similar to planarian queries. A total of 1604 proteins were identified. The mucous subproteome was defined through analysis of a mucous trail fraction and an extract obtained by treating whole worms with the mucolytic agent N-acetylcysteine. Gene Ontology analysis confirmed that the mucous fractions were enriched with secreted proteins. The S. mediterranea proteome is highly similar to that predicted for the trematode Schistosoma mansoni associated with intestinal schistosomiasis, with the mucous subproteome particularly highly conserved. Remarkably, orthologs of 119 planarian mucous proteins are present in human mucosal secretions and tear fluid. We suggest planarians have potential to be a model system for the characterization of mucous protein function and relevant to parasitic flatworm infections and diseases underlined by mucous aberrancies, such as cystic fibrosis, asthma, and other lung diseases. PMID:22653920

  3. Venus Kinase Receptors Control Reproduction in the Platyhelminth Parasite Schistosoma mansoni

    PubMed Central

    Cailliau, Katia; Morel, Marion; Hahnel, Steffen; Leutner, Silke; Beckmann, Svenja; Grevelding, Christoph G.; Dissous, Colette

    2014-01-01

    The Venus Kinase Receptor (VKR) is a single transmembrane molecule composed of an intracellular tyrosine kinase domain close to that of insulin receptor and an extracellular Venus Flytrap (VFT) structure similar to the ligand binding domain of many class C G Protein Coupled Receptors. This receptor tyrosine kinase (RTK) was first discovered in the platyhelminth parasite Schistosoma mansoni, then in a large variety of invertebrates. A single vkr gene is found in most genomes, except in S. mansoni in which two genes Smvkr1 and Smvkr2 exist. VKRs form a unique family of RTKs present only in invertebrates and their biological functions are still to be discovered. In this work, we show that SmVKRs are expressed in the reproductive organs of S. mansoni, particularly in the ovaries of female worms. By transcriptional analyses evidence was obtained that both SmVKRs fulfill different roles during oocyte maturation. Suppression of Smvkr expression by RNA interference induced spectacular morphological changes in female worms with a strong disorganization of the ovary, which was dominated by the presence of primary oocytes, and a defect of egg formation. Following expression in Xenopus oocytes, SmVKR1 and SmVKR2 receptors were shown to be activated by distinct ligands which are L-Arginine and calcium ions, respectively. Signalling analysis in Xenopus oocytes revealed the capacity of SmVKRs to activate the PI3K/Akt/p70S6K and Erk MAPK pathways involved in cellular growth and proliferation. Additionally, SmVKR1 induced phosphorylation of JNK (c-Jun N-terminal kinase). Activation of JNK by SmVKR1 was supported by the results of yeast two-hybrid experiments identifying several components of the JNK pathway as specific interacting partners of SmVKR1. In conclusion, these results demonstrate the functions of SmVKR in gametogenesis, and particularly in oogenesis and egg formation. By eliciting signalling pathways potentially involved in oocyte proliferation, growth and migration

  4. New Acotylea (Polycladida, Platyhelminthes) from the east coast of the North Atlantic Ocean with special mention of the Iberian littoral.

    PubMed

    Noreña, Carolina; Rodríguez, Jorge; Pérez, Jacinto; Almon, Bruno

    2015-01-01

    Polyclad species diversity, although generally well known for European North Atlantic waters, is nearly unknown for the Iberian Peninsula. The "Ría de Arousa", located on the Atlantic coast of Galicia (Spain), is a place where many positive biological factors for species biodiversity converge. Therefore, it is an ideal location to study polyclad diversity. This research, which describes new records and new species, contributes to the knowledge of the distribution of Polycladida (Platyhelminthes), particularly of the suborder Acotylea, in the Atlantic waters of the Iberian Peninsula. The new records include the re-descriptions of Cryptocelis compacta Lang, 1884, Stylochus neapolitanus (Delle Chiaje, 1841-1844) and Discocelis tigrina (Blanchard, 1847), while the two newly described species are Hoploplana elisabelloi n. sp. and Armatoplana celta n. sp. PMID:26624472

  5. Immunoenzymatic visualization of tetrodotoxin (TTX) in Cephalothrix species (Nemertea: Anopla: Palaeonemertea: Cephalotrichidae) and Planocera reticulata (Platyhelminthes: Turbellaria: Polycladida: Planoceridae).

    PubMed

    Tanu, Mohosena Begum; Mahmud, Yahia; Arakawa, Osamu; Takatani, Tomohiro; Kajihara, Hiroshi; Kawatsu, Kentaro; Hamano, Yonekazu; Asakawa, Manabu; Miyazawa, Keisuke; Noguchi, Tamao

    2004-10-01

    Tetrodotoxin (TTX) was localized as brown color in different tissues of an undescribed species of the nemertean genus Cephalothrix (phylum Nemertea) and a turbellarian Planocera reticulata (phylum Platyhelminthes) on light microscopy by means of a monoclonal anti-TTX antibody. In the Cephalothrix sp., TTX was recognized in the vesicles apically arranged in the bacillary cells in the epidermis, basal lamina, the granular cells in the proboscis epithelium, rhynchocoel epithelium, and the vesicles in the basal portion of the intestinal wall near the blood vessels and rhynchocoel. The excretory system and the ovum also showed positive reaction of TTX antigen-antibody. On the other hand, the hermaphrodite flatworm P. reticulata exhibited TTX antigen-antibody complex only in their ovum. To our knowledge, this is the first experimental effort on micro-distribution of TTX in invertebrates. PMID:15450926

  6. Preparation of the planarian Schmidtea mediterranea for high-resolution histology and transmission electron microscopy

    PubMed Central

    Brubacher, John L.; Vieira, Ana P.; Newmark, Phillip A.

    2014-01-01

    The flatworm Schmidtea mediterranea is an emerging model species in such fields as stem-cell biology, regeneration, and evolutionary biology. Excellent molecular tools have been developed for S. mediterranea, but ultrastructural techniques have received far less attention. Processing specimens for histology and transmission electron microscopy is notoriously idiosyncratic for particular species or specimen types. Unfortunately however, most methods for S. mediterranea described in the literature lack numerous essential details, and those few that do provide them rely on specialized equipment that may not be readily available. Here we present an optimized protocol for ultrastructural preparation of S. mediterranea. The protocol can be completed in six days, much of which is “hands-off” time. To aid with troubleshooting, we also illustrate the significant effects of seemingly minor variations in fixative, buffer concentration, and dehydration steps. This procedure will be useful for all planarian researchers, particularly those with relatively little experience in tissue processing. PMID:24556788

  7. Global irradiation effects, stem cell genes and rare transcripts in the planarian transcriptome.

    PubMed

    Galloni, Mireille

    2012-01-01

    Stem cells are the closest relatives of the totipotent primordial cell, which is able to spawn millions of daughter cells and hundreds of cell types in multicellular organisms. Stem cells are involved in tissue homeostasis and regeneration, and may play a major role in cancer development. Among animals, planarians host a model stem cell type, called the neoblast, which essentially confers immortality. Gaining insights into the global transcriptional landscape of these exceptional cells takes an unprecedented turn with the advent of Next Generation Sequencing methods. Two Digital Gene Expression transcriptomes of Schmidtea mediterranea planarians, with or without neoblasts lost through irradiation, were produced and analyzed. Twenty one bp NlaIII tags were mapped to transcripts in the Schmidtea and Dugesia taxids. Differential representation of tags in normal versus irradiated animals reflects differential gene expression. Canonical and non-canonical tags were included in the analysis, and comparative studies with human orthologs were conducted. Transcripts fell into 3 categories: invariant (including housekeeping genes), absent in irradiated animals (potential neoblast-specific genes, IRDOWN) and induced in irradiated animals (potential cellular stress response, IRUP). Different mRNA variants and gene family members were recovered. In the IR-DOWN class, almost all of the neoblast-specific genes previously described were found. In irradiated animals, a larger number of genes were induced rather than lost. A significant fraction of IRUP genes behaved as if transcript versions of different lengths were produced. Several novel potential neoblast-specific genes have been identified that varied in relative abundance, including highly conserved as well as novel proteins without predicted orthologs. Evidence for a large body of antisense transcripts, for example regulated antisense for the Smed-piwil1 gene, and evidence for RNA shortening in irradiated animals is presented

  8. Ammonia toxicity to the freshwater planarian Polycelis felina: contrasting effects of continuous versus discontinuous exposures.

    PubMed

    Alonso, Álvaro; Camargo, Julio A

    2015-05-01

    Aquatic animals can be exposed to fluctuating concentrations of toxicants. In fact, for some toxicants (i.e., pesticides, ammonia), discontinuous exposure is more environmentally relevant than constant exposure. Responses of aquatic animals to each type of exposure may be different. However, despite the high ecological relevance of behaviour, there is still scarce information on the effects of discontinuous exposure on behaviour. Our study focused on the assessment of unionized ammonia toxicity on the behaviour of a freshwater planarian under continuous exposure (3 days of exposure and 18 days of recovery) versus discontinuous exposure (3 pulses of 1 day with 6 days of recovery between pulses = total 3 days of exposure and 18 days of recovery). Behaviour was assessed as locomotion activity. Bioassays with continuous and discontinuous exposure were performed with one control and five unionized ammonia concentrations (0.14-0.35 mg N-NH3/L). Unionized ammonia in continuous exposure caused less impact on behaviour than equivalent concentrations provided in a discontinuous exposure. By contrast, continuous exposures caused more impact on survival. The discontinuous exposure may allow detoxification during recovery periods, thus increasing the probability of survival in the next pulse. Under continuous exposure, the mortality threshold could be exceeded, and animals could die in greater proportion during exposure as well as the recovery period. We conclude that behavioural activity was a sensitive endpoint to assess the contrasting effects of continuous versus discontinuous exposure and that the response of planarians to discontinuous exposure is different to its response to continuous exposure. PMID:25604922

  9. Molecular analysis of stem cells and their descendents during cell turnover and regeneration in the planarian Schmidtea mediterranea

    PubMed Central

    Eisenhoffer, George T.; Kang, Hara; Alvarado, Alejandro Sánchez

    2008-01-01

    In adult planarians the replacement of cells lost to physiological turnover or injury is sustained by the proliferation and differentiation of stem cells known as neoblasts. Neoblast lineage relationships and the molecular changes that take place during differentiation into the appropriate cell types are poorly understood. Here we report the identification and characterization of a cohort of genes specifically expressed in neoblasts and their descendents. We find that genes with severely downregulated expression after irradiation molecularly define at least three discrete subpopulations of cells. Simultaneous BrdU labeling and in situ hybridization experiments in intact and regenerating animals indicate that these cell subpopulations are related by lineage. Our data demonstrate not only the ability to measure and study the in vivo population dynamics of adult stem cells during tissue homeostasis and regeneration, but also the utility of studies in planarians to broadly inform stem cell biology in adult organisms. PMID:18786419

  10. Two distinct roles of the yorkie/yap gene during homeostasis in the planarian Dugesia japonica

    PubMed Central

    Hwang, Byulnim; An, Yang; Agata, Kiyokazu; Umesono, Yoshihiko

    2015-01-01

    Adult planarians possess somatic pluripotent stem cells called neoblasts that give rise to all missing cell types during regeneration and homeostasis. Recent studies revealed that the Yorkie (Yki)/Yes-associated protein (YAP) transcriptional coactivator family plays an important role in the regulation of tissue growth during development and regeneration, and therefore we investigated the role of a planarian yki-related gene (termed Djyki) during regeneration and homeostasis of the freshwater planarian Dugesia japonica. We found that knockdown of the function of Djyki by RNA interference (RNAi) downregulated neoblast proliferation and caused regeneration defects after amputation. In addition, Djyki RNAi caused edema during homeostasis. These seemingly distinct defects induced by Djyki RNAi were rescued by simultaneous RNAi of a planarian mats-related gene (termed Djmats), suggesting an important role of Djmats in the negative regulation of Djyki, in accordance with the conservation of the functional relationship of these two genes during the course of evolution. Interestingly, Djyki RNAi did not prevent normal protonephridial structure, suggesting that Djyki RNAi induced the edema phenotype without affecting the excretory system. Further analyses revealed that increased expression of the D. japonica gene DjaquaporinA (DjaqpA), which belongs to a large gene family that encodes a water channel protein for the regulation of transcellular water flow, promoted the induction of edema, but not defects in neoblast dynamics, in Djyki(RNAi) animals. Thus, we conclude that Djyki plays two distinct roles in the regulation of active proliferation of stem cells and in osmotic water transport across the body surface in D. japonica. PMID:25708270

  11. Planarians as a model of aging to study the interaction between stem cells and senescent cells in vivo

    PubMed Central

    Perrigue, Patrick M.; Najbauer, Joseph; Jozwiak, Agnieszka A.; Barciszewski, Jan; Aboody, Karen S.; Barish, Michael E.

    2015-01-01

    The depletion of stem cell pools and the accumulation of senescent cells in animal tissues are linked to aging. Planarians are invertebrate flatworms and are unusual in that their stem cells, called neoblasts, are constantly replacing old and dying cells. By eliminating neoblasts in worms via irradiation, the biological principles of aging are exposed in the absence of wound healing and regeneration, making planaria a powerful tool for aging research. PMID:26654402

  12. Specific features of the planarian Dugesia tigrina regeneration and mollusk Helix albescens nociception under weak electromagnetic shielding

    NASA Astrophysics Data System (ADS)

    Temur'yants, N. A.; Demtsun, N. A.; Kostyuk, A. S.; Yarmolyuk, N. S.

    2012-12-01

    It has been demonstrated that weak electromagnetic shielding stimulates regeneration in the planarian Dugesia tigrina, the stimulating intensity being dependent on both the initial state of the animals, which is determined by season, and their functional asymmetry. As has been shown, the effect of a weak electromagnetic field induces phasic changes in the nociceptive sensitivity of the mollusk Helix albescens: an increase in the sensitivity to a thermal stimulus is replaced by the development of the hypalgesic effect.

  13. Conserved functional antagonism of CELF and MBNL proteins controls stem cell-specific alternative splicing in planarians

    PubMed Central

    Solana, Jordi; Irimia, Manuel; Ayoub, Salah; Orejuela, Marta Rodriguez; Zywitza, Vera; Jens, Marvin; Tapial, Javier; Ray, Debashish; Morris, Quaid; Hughes, Timothy R; Blencowe, Benjamin J; Rajewsky, Nikolaus

    2016-01-01

    In contrast to transcriptional regulation, the function of alternative splicing (AS) in stem cells is poorly understood. In mammals, MBNL proteins negatively regulate an exon program specific of embryonic stem cells; however, little is known about the in vivo significance of this regulation. We studied AS in a powerful in vivo model for stem cell biology, the planarian Schmidtea mediterranea. We discover a conserved AS program comprising hundreds of alternative exons, microexons and introns that is differentially regulated in planarian stem cells, and comprehensively identify its regulators. We show that functional antagonism between CELF and MBNL factors directly controls stem cell-specific AS in planarians, placing the origin of this regulatory mechanism at the base of Bilaterians. Knockdown of CELF or MBNL factors lead to abnormal regenerative capacities by affecting self-renewal and differentiation sets of genes, respectively. These results highlight the importance of AS interactions in stem cell regulation across metazoans. DOI: http://dx.doi.org/10.7554/eLife.16797.001 PMID:27502555

  14. Riluzole attenuates the effects of chemoconvulsants acting on glutamatergic and GABAergic neurotransmission in the planarian Dugesia tigrina.

    PubMed

    Ramakrishnan, Latha; Dalhoff, Zachary; Fettig, Samantha L; Eggerichs, Michael R; Nelson, Briegette E; Shrestha, Bibita; Elshikh, Amira H; Karki, Pratima

    2013-10-15

    Planarians, the non-parasitic flatworms, display dose-dependent, distinct (C-like and corkscrew-like) hyperkinesias upon exposure to 0.001-10 mM aqueous solutions of glutamatergic agonists (L-glutamate and N-methyl-D-aspartate (NMDA)) and 0.001-5 mM concentrations of the glutamate decarboxylase (GAD) inhibitor (semicarbazide). In the planarian seizure-like activity (PSLA) experiments the three chemoconvulsants displayed the following order of potency (EC50): L-glutamate (0.6mM)>NMDA (1.4 mM)>semicarbazide (4.5mM). Planarian hyperkinesias behavior counting experiments also revealed that riluzole (0.001 to 1mM), an anti-convulsive agent, displayed no significant behavioral activity by itself, but attenuated hyperkinesias elicited by the three chemoconvulsants targeting either glutamatergic or GABAergic neurotransmission with the following order of potency (IC50): NMDA (44.7 µM)>semicarbazide (88.3 µM)>L-glutamate (160 µM). Further, (+)-MK-801, a specific NMDA antagonist, alleviated 3mM NMDA (47%) or 3mM L-glutamate (27%) induced planarian hyperkinesias. The results provide pharmacological evidence for the presence of glutamatergic receptor-like and semicarbazide sensitive functional GAD enzyme-like proteins in planaria in addition to demonstrating, for the first time, the anti-convulsive effects of riluzole in an invertebrate model. High performance liquid chromatography coupled with fluorescence detection (HPLC-F) analysis performed on planarian extracts post no drug treatment (control) or treatment with 3mM semicarbazide, combination of 3mM semicarbazide and 0.1 mM riluzole, or 0.1 mM riluzole revealed that 3 mM semicarbazide induced 35% decrease in the GABA levels and a combination of 3mM semicarbazide and 0.1 mM riluzole induced 42% decrease in glutamate levels with respect to the control group. PMID:23872399

  15. Ethanol and cocaine: environmental place conditioning, stereotypy, and synergism in planarians.

    PubMed

    Tallarida, Christopher S; Bires, Kristopher; Avershal, Jacob; Tallarida, Ronald J; Seo, Stephanie; Rawls, Scott M

    2014-09-01

    More than 90% of individuals who use cocaine also report concurrent ethanol use, but only a few studies, all conducted with vertebrates, have investigated pharmacodynamic interactions between ethanol and cocaine. Planaria, a type of flatworm often considered to have the simplest 'brain,' is an invertebrate species especially amenable to the quantification of drug-induced behavioral responses and identification of conserved responses. Here, we investigated stereotypical and environmental place conditioning (EPC) effects of ethanol administered alone and in combination with cocaine. Planarians displayed concentration-related increases in C-shaped movements following exposure to ethanol (0.01-1%) (maximal effect: 9.9±1.1 C-shapes/5 min at 0.5%) or cocaine (0.1-5 mM) (maximal effect: 42.8±4.1 C-shapes/5 min at 5 mM). For combined administration, cocaine (0.1-5 mM) was tested with submaximal ethanol concentrations (0.01, 0.1%); the observed effect for the combination was enhanced compared to its predicted effect, indicating synergism for the interaction. The synergy with ethanol was specific for cocaine, as related experiments revealed that combinations of ethanol and nicotine did not result in synergy. For EPC experiments, ethanol (0.0001-1%) concentration-dependently increased EPC, with significant environmental shifts detected at 0.01 and 1%. Cocaine (0.001-1 μM) produced an inverted U-shaped concentration-effect curve, with a significant environmental shift observed at 0.01 μM. For combined exposure, variable cocaine concentrations (0.001-1 μM) were administered with a statistically ineffective concentration of ethanol (0.0001%). For each concentration of cocaine, the environmental shift was enhanced by ethanol, with significance detected at 1 μM. Cocaethylene, a metabolite of cocaine and ethanol, also produced C-shapes and EPC. Lidocaine (0.001-10 μM), an anesthetic and analog of cocaine, did not produce EPC or C-shaped movements. Evidence from planarians

  16. Ethanol and cocaine: environmental place conditioning, stereotypy and synergism in planarians

    PubMed Central

    Tallarida, Christopher S.; Bires, Kristopher; Avershal, Jacob; Tallarida, Ronald J.; Seo, Stephanie; Rawls, Scott M.

    2015-01-01

    More than 90% of individuals who use cocaine also report concurrent ethanol use, but only a few studies, all conducted with vertebrates, have investigated pharmacodynamic interactions between ethanol and cocaine. Planaria, a type of flatworm often considered to have the simplest ‘brain’, is an invertebrate species especially amenable to the quantification of drug-induced behavioral responses and identification of conserved responses. Here, we investigated stereotypical and environmental place conditioning (EPC) effects of ethanol administered alone and in combination with cocaine. Planarians displayed concentration-related increases in C-shape movements following exposure to ethanol (0.01 – 1%) (maximal effect: 9.9 ± 1.1 C-shapes/5 min at 0.5%) or cocaine (0.1 – 5 mM) (maximal effect: 42.8 ± 4.1 C-shapes/5 min at 5 mM). For combined administration, cocaine (0.1 – 5 mM) were tested with submaximal ethanol concentrations (0.01, 0,1%), the observed effect for the combination was enhanced compared to its predicted effect, indicating synergism for the interaction. The synergy with ethanol was specific for cocaine, as related experiments revealed that combinations of ethanol and nicotine did not result in synergy. For EPC experiments, ethanol (0.0001 – 1%) concentration-dependently increased EPC, with significant environmental shifts detected at 0.01 and 1%. Cocaine (0.001 – 1 μM) produced an inverted U-shaped concentration-effect curve, with a significant environmental shift observed at 0.01 μM. For combined exposure, variable cocaine concentrations (0.001 – 1 μM) were administered with a statistically ineffective concentration of ethanol (0.0001%). For each concentration of cocaine, the environmental shift was enhanced by ethanol, with significance detected at 1 μM. Cocaethylene, a metabolite of cocaine and ethanol, also produced C-shapes and EPC. Lidocaine (0.001 – 10 μM), an anesthetic and analog of cocaine, did not produce EPC or C

  17. A new genus and species for the first recorded cave-dwelling Cavernicola (Platyhelminthes) from South America

    PubMed Central

    Leal-Zanchet, Ana Maria; de Souza, Stella Teles; Ferreira, Rodrigo Lopes

    2014-01-01

    Abstract Species diversity of Brazilian cave fauna has been seriously underestimated. A karst area located in Felipe Guerra, northeastern Brazil, which is a hotspot of subterranean diversity in Brazil, has revealed more than 20 troglobitic species, most of them still undescribed. Based on recent samplings in this karst area, we document the occurrence of the suborder Cavernicola (Platyhelminthes) in South American hypogean environments for the first time and describe a new genus and species for this suborder. Hausera Leal-Zanchet & Souza, gen. n. has features concordant with those defined for the family Dimarcusidae. The new genus is characterized by two unique features, viz. an intestine extending dorsally to the brain and ovovitelline ducts located dorsally to the nerve cords, which is complemented by a combination of other characters. The type-specimens of Hausera hauseri Leal-Zanchet & Souza, sp. n. are typical stygobionts, unpigmented and eyeless, and they may constitute an oceanic relict as is the case of other stygobiotic invertebrates found in this karst area in northeastern Brazil. PMID:25349486

  18. No evidence for a culturable bacterial tetrodotoxin producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida).

    PubMed

    Salvitti, Lauren R; Wood, Susanna A; McNabb, Paul; Cary, Stephen Craig

    2015-02-01

    Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography-mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464

  19. Complete Sequence of the mitochondrial genome of the tapeworm Hymenolepis diminuta: Gene arrangements indicate that platyhelminths are eutrochozoans

    SciTech Connect

    von Nickisch-Rosenegk, Markus; Brown, Wesley M.; Boore, Jeffrey L.

    2001-01-01

    Using ''long-PCR'' we have amplified in overlapping fragments the complete mitochondrial genome of the tapeworm Hymenolepis diminuta (Platyhelminthes: Cestoda) and determined its 13,900 nucleotide sequence. The gene content is the same as that typically found for animal mitochondrial DNA (mtDNA) except that atp8 appears to be lacking, a condition found previously for several other animals. Despite the small size of this mtDNA, there are two large non-coding regions, one of which contains 13 repeats of a 31 nucleotide sequence and a potential stem-loop structure of 25 base pairs with an 11-member loop. Large potential secondary structures are identified also for the non-coding regions of two other cestode mtDNAs. Comparison of the mitochondrial gene arrangement of H. diminuta with those previously published supports a phylogenetic position of flatworms as members of the Eutrochozoa, rather than being basal to either a clade of protostomes or a clade of coelomates.

  20. No Evidence for a Culturable Bacterial Tetrodotoxin Producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida)

    PubMed Central

    Salvitti, Lauren R.; Wood, Susanna A.; McNabb, Paul; Cary, Stephen Craig

    2015-01-01

    Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography—mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464

  1. A planarian p53 homolog regulates proliferation and self-renewal in adult stem cell lineages

    PubMed Central

    Pearson, Bret J.; Alvarado, Alejandro Sánchez

    2010-01-01

    The functions of adult stem cells and tumor suppressor genes are known to intersect. However, when and how tumor suppressors function in the lineages produced by adult stem cells is unknown. With a large population of stem cells that can be manipulated and studied in vivo, the freshwater planarian is an ideal system with which to investigate these questions. Here, we focus on the tumor suppressor p53, homologs of which have no known role in stem cell biology in any invertebrate examined thus far. Planaria have a single p53 family member, Smed-p53, which is predominantly expressed in newly made stem cell progeny. When Smed-p53 is targeted by RNAi, the stem cell population increases at the expense of progeny, resulting in hyper-proliferation. However, ultimately the stem cell population fails to self-renew. Our results suggest that prior to the vertebrates, an ancestral p53-like molecule already had functions in stem cell proliferation control and self-renewal. PMID:20040488

  2. zic-1 Expression in Planarian Neoblasts after Injury Controls Anterior Pole Regeneration

    PubMed Central

    Vásquez-Doorman, Constanza; Petersen, Christian P.

    2014-01-01

    Mechanisms that enable injury responses to prompt regenerative outgrowth are not well understood. Planarians can regenerate essentially any tissue removed by wounding, even after decapitation, due to robust regulation of adult pluripotent stem cells of the neoblast population. Formation of pole signaling centers involving Wnt inhibitors or Wnt ligands promotes head or tail regeneration, respectively, and this process requires the use of neoblasts early after injury. We used expression profiling of purified neoblasts to identify factors needed for anterior pole formation. Using this approach, we identified zic-1, a Zic-family transcription factor, as transcriptionally activated in a subpopulation of neoblasts near wound sites early in head regeneration. As head regeneration proceeds, the Wnt inhibitor notum becomes expressed in the newly forming anterior pole in zic-1-expressing cells descended from neoblasts. Inhibition of zic-1 by RNAi resulted in a failure to express notum at the anterior pole and to regenerate a head, but did not affect tail regeneration. Both injury and canonical Wnt signaling inhibition are required for zic-1 expression, and double-RNAi experiments suggest zic-1 inhibits Wnt signaling to allow head regeneration. Analysis of neoblast fate determinants revealed that zic-1 controls specification of notum-expressing cells from foxD-expressing neoblasts to form the anterior pole, which organizes subsequent outgrowth. Specialized differentiation programs may in general underlie injury-dependent formation of tissue organizing centers used for regenerative outgrowth. PMID:24992682

  3. A planarian p53 homolog regulates proliferation and self-renewal in adult stem cell lineages.

    PubMed

    Pearson, Bret J; Sánchez Alvarado, Alejandro

    2010-01-01

    The functions of adult stem cells and tumor suppressor genes are known to intersect. However, when and how tumor suppressors function in the lineages produced by adult stem cells is unknown. With a large population of stem cells that can be manipulated and studied in vivo, the freshwater planarian is an ideal system with which to investigate these questions. Here, we focus on the tumor suppressor p53, homologs of which have no known role in stem cell biology in any invertebrate examined thus far. Planaria have a single p53 family member, Smed-p53, which is predominantly expressed in newly made stem cell progeny. When Smed-p53 is targeted by RNAi, the stem cell population increases at the expense of progeny, resulting in hyper-proliferation. However, ultimately the stem cell population fails to self-renew. Our results suggest that prior to the vertebrates, an ancestral p53-like molecule already had functions in stem cell proliferation control and self-renewal. PMID:20040488

  4. Reactive Oxygen Species in Planarian Regeneration: An Upstream Necessity for Correct Patterning and Brain Formation

    PubMed Central

    Pirotte, Nicky; Stevens, An-Sofie; Fraguas, Susanna; Plusquin, Michelle; Van Roten, Andromeda; Van Belleghem, Frank; Paesen, Rik; Ameloot, Marcel; Cebrià, Francesc; Artois, Tom; Smeets, Karen

    2015-01-01

    Recent research highlighted the impact of ROS as upstream regulators of tissue regeneration. We investigated their role and targeted processes during the regeneration of different body structures using the planarian Schmidtea mediterranea, an organism capable of regenerating its entire body, including its brain. The amputation of head and tail compartments induces a ROS burst at the wound site independently of the orientation. Inhibition of ROS production by diphenyleneiodonium (DPI) or apocynin (APO) causes regeneration defaults at both the anterior and posterior wound sites, resulting in reduced regeneration sites (blastemas) and improper tissue homeostasis. ROS signaling is necessary for early differentiation and inhibition of the ROS burst results in defects on the regeneration of the nervous system and on the patterning process. Stem cell proliferation was not affected, as indicated by histone H3-P immunostaining, fluorescence-activated cell sorting (FACS), in situ hybridization of smedwi-1, and transcript levels of proliferation-related genes. We showed for the first time that ROS modulate both anterior and posterior regeneration in a context where regeneration is not limited to certain body structures. Our results indicate that ROS are key players in neuroregeneration through interference with the differentiation and patterning processes. PMID:26180588

  5. Wnt, Ptk7, and FGFRL expression gradients control trunk positional identity in planarian regeneration

    PubMed Central

    Lander, Rachel; Petersen, Christian P

    2016-01-01

    Mechanisms enabling positional identity re-establishment are likely critical for tissue regeneration. Planarians use Wnt/beta-catenin signaling to polarize the termini of their anteroposterior axis, but little is known about how regeneration signaling restores regionalization along body or organ axes. We identify three genes expressed constitutively in overlapping body-wide transcriptional gradients that control trunk-tail positional identity in regeneration. ptk7 encodes a trunk-expressed kinase-dead Wnt co-receptor, wntP-2 encodes a posterior-expressed Wnt ligand, and ndl-3 encodes an anterior-expressed homolog of conserved FGFRL/nou-darake decoy receptors. ptk7 and wntP-2 maintain and allow appropriate regeneration of trunk tissue position independently of canonical Wnt signaling and with suppression of ndl-3 expression in the posterior. These results suggest that restoration of regional identity in regeneration involves the interpretation and re-establishment of axis-wide transcriptional gradients of signaling molecules. DOI: http://dx.doi.org/10.7554/eLife.12850.001 PMID:27074666

  6. Gene expression of pluripotency determinants is conserved between mammalian and planarian stem cells

    PubMed Central

    Önal, Pinar; Grün, Dominic; Adamidi, Catherine; Rybak, Agnieszka; Solana, Jordi; Mastrobuoni, Guido; Wang, Yongbo; Rahn, Hans-Peter; Chen, Wei; Kempa, Stefan; Ziebold, Ulrike; Rajewsky, Nikolaus

    2012-01-01

    Freshwater planaria possess extreme regeneration capabilities mediated by abundant, pluripotent stem cells (neoblasts) in adult animals. Although planaria emerged as an attractive in vivo model system for stem cell biology, gene expression in neoblasts has not been profiled comprehensively and it is unknown how molecular mechanisms for pluripotency in neoblasts relate to those in mammalian embryonic stem cells (ESCs). We purified neoblasts and quantified mRNA and protein expression by sequencing and shotgun proteomics. We identified ∼4000 genes specifically expressed in neoblasts, including all ∼30 known neoblast markers. Genes important for pluripotency in ESCs, including regulators as well as targets of OCT4, were well conserved and upregulated in neoblasts. We found conserved expression of epigenetic regulators and demonstrated their requirement for planarian regeneration by knockdown experiments. Post-transcriptional regulatory genes characteristic for germ cells were also enriched in neoblasts, suggesting the existence of a common ancestral state of germ cells and ESCs. We conclude that molecular determinants of pluripotency are conserved throughout evolution and that planaria are an informative model system for human stem cell biology. PMID:22543868

  7. Wnt, Ptk7, and FGFRL expression gradients control trunk positional identity in planarian regeneration.

    PubMed

    Lander, Rachel; Petersen, Christian P

    2016-01-01

    Mechanisms enabling positional identity re-establishment are likely critical for tissue regeneration. Planarians use Wnt/beta-catenin signaling to polarize the termini of their anteroposterior axis, but little is known about how regeneration signaling restores regionalization along body or organ axes. We identify three genes expressed constitutively in overlapping body-wide transcriptional gradients that control trunk-tail positional identity in regeneration. ptk7 encodes a trunk-expressed kinase-dead Wnt co-receptor, wntP-2 encodes a posterior-expressed Wnt ligand, and ndl-3 encodes an anterior-expressed homolog of conserved FGFRL/nou-darake decoy receptors. ptk7 and wntP-2 maintain and allow appropriate regeneration of trunk tissue position independently of canonical Wnt signaling and with suppression of ndl-3 expression in the posterior. These results suggest that restoration of regional identity in regeneration involves the interpretation and re-establishment of axis-wide transcriptional gradients of signaling molecules. PMID:27074666

  8. Toxicity of a hazardous chemical mixture in the planarian, Dugesia dorotocephala

    SciTech Connect

    Ramsdell, H.S.; Matthews, C.M.

    1995-12-31

    The responses of the planarian, Dugesia dorotocephala to toxic chemical mixtures representative of water contaminants associated with hazardous waste sites have been studied in laboratory experiments. These free-living flatworms are readily maintained under laboratory conditions and are a useful invertebrate model for toxicology studies. Their widespread occurrence also makes them potentially useful for environmental studies. Mature asexual Dugesia dorotocephala were exposed for 14 days to mixtures of seven contaminants frequently detected in water at hazardous waste sites. The complete 1X mixture contained both metals (As, 3.1 ppm; Cr, 0.7 ppm; Pb, 3.7 ppm) and organics (chloroform, 1.5 ppm; benzene, 5.0 ppm; phenol, 3.4 ppm; trichloroethylene, 3.8 ppm). Groups of planaria were treated with the complete mixture at 0.1X, 1X and 10X concentrations. Additional groups were exposed to the metals-only or organics-only submixtures, also at 0.1X, 1X and 10X concentrations. Treatment solutions were renewed daily. Suppression of fissioning was observed in all of the 1X and 10X treatment groups. Significant mortality occurred only in the 10X complete and 1 0X metals-only treatments. It appears that the toxic effects of the complete mixture are primarily associated with the metal components.

  9. A Generic and Cell-Type-Specific Wound Response Precedes Regeneration in Planarians.

    PubMed

    Wurtzel, Omri; Cote, Lauren E; Poirier, Amber; Satija, Rahul; Regev, Aviv; Reddien, Peter W

    2015-12-01

    Regeneration starts with injury. Yet how injuries affect gene expression in different cell types and how distinct injuries differ in gene expression remain unclear. We defined the transcriptomes of major cell types of planarians--flatworms that regenerate from nearly any injury--and identified 1,214 tissue-specific markers across 13 cell types. RNA sequencing on 619 single cells revealed that wound-induced genes were expressed either in nearly all cell types or specifically in one of three cell types (stem cells, muscle, or epidermis). Time course experiments following different injuries indicated that a generic wound response is activated with any injury regardless of the regenerative outcome. Only one gene, notum, was differentially expressed early between anterior- and posterior-facing wounds. Injury-specific transcriptional responses emerged 30 hr after injury, involving context-dependent patterning and stem-cell-specialization genes. The regenerative requirement of every injury is different; however, our work demonstrates that all injuries start with a common transcriptional response. PMID:26651295

  10. Regional signals in the planarian body guide stem cell fate in the presence of genomic instability.

    PubMed

    Peiris, T Harshani; Ramirez, Daniel; Barghouth, Paul G; Ofoha, Udokanma; Davidian, Devon; Weckerle, Frank; Oviedo, Néstor J

    2016-05-15

    Cellular fate decisions are influenced by their topographical location in the adult body. For instance, tissue repair and neoplastic growth are greater in anterior than in posterior regions of adult animals. However, the molecular underpinnings of these regional differences are unknown. We identified a regional switch in the adult planarian body upon systemic disruption of homologous recombination with RNA-interference of Rad51 Rad51 knockdown increases DNA double-strand breaks (DSBs) throughout the body, but stem cells react differently depending on their location along the anteroposterior axis. In the presence of extensive DSBs, cells in the anterior part of the body resist death, whereas cells in the posterior region undergo apoptosis. Furthermore, we found that proliferation of cells with DNA damage is induced in the presence of brain tissue and that the retinoblastoma pathway enables overproliferation of cells with DSBs while attending to the demands of tissue growth and repair. Our results implicate both autonomous and non-autonomous mechanisms as key mediators of regional cell behavior and cellular transformation in the adult body. PMID:27013241

  11. Amputation induces stem cell mobilization to sites of injury during planarian regeneration

    PubMed Central

    Guedelhoefer, Otto C.; Alvarado, Alejandro Sánchez

    2012-01-01

    How adult stem cell populations are recruited for tissue renewal and repair is a fundamental question of biology. Mobilization of stem cells out of their niches followed by correct migration and differentiation at a site of tissue turnover or injury are important requirements for proper tissue maintenance and regeneration. However, we understand little about the mechanisms that control this process, possibly because the best studied vertebrate adult stem cell systems are not readily amenable to in vivo observation. Furthermore, few clear examples of the recruitment of fully potent stem cells, compared with limited progenitors, are known. Here, we show that planarian stem cells directionally migrate to amputation sites during regeneration. We also show that during tissue homeostasis they are stationary. Our study not only uncovers the existence of specific recruitment mechanisms elicited by amputation, but also sets the stage for the systematic characterization of evolutionarily conserved stem cell regulatory processes likely to inform stem cell function and dysfunction in higher organisms, including humans. PMID:22899852

  12. JNK Controls the Onset of Mitosis in Planarian Stem Cells and Triggers Apoptotic Cell Death Required for Regeneration and Remodeling

    PubMed Central

    Almuedo-Castillo, María; Crespo, Xenia; Seebeck, Florian; Bartscherer, Kerstin; Salò, Emili; Adell, Teresa

    2014-01-01

    Regeneration of lost tissues depends on the precise interpretation of molecular signals that control and coordinate the onset of proliferation, cellular differentiation and cell death. However, the nature of those molecular signals and the mechanisms that integrate the cellular responses remain largely unknown. The planarian flatworm is a unique model in which regeneration and tissue renewal can be comprehensively studied in vivo. The presence of a population of adult pluripotent stem cells combined with the ability to decode signaling after wounding enable planarians to regenerate a complete, correctly proportioned animal within a few days after any kind of amputation, and to adapt their size to nutritional changes without compromising functionality. Here, we demonstrate that the stress-activated c-jun–NH2–kinase (JNK) links wound-induced apoptosis to the stem cell response during planarian regeneration. We show that JNK modulates the expression of wound-related genes, triggers apoptosis and attenuates the onset of mitosis in stem cells specifically after tissue loss. Furthermore, in pre-existing body regions, JNK activity is required to establish a positive balance between cell death and stem cell proliferation to enable tissue renewal, remodeling and the maintenance of proportionality. During homeostatic degrowth, JNK RNAi blocks apoptosis, resulting in impaired organ remodeling and rescaling. Our findings indicate that JNK-dependent apoptotic cell death is crucial to coordinate tissue renewal and remodeling required to regenerate and to maintain a correctly proportioned animal. Hence, JNK might act as a hub, translating wound signals into apoptotic cell death, controlled stem cell proliferation and differentiation, all of which are required to coordinate regeneration and tissue renewal. PMID:24922054

  13. Smed-SmB, a member of the LSm protein superfamily, is essential for chromatoid body organization and planarian stem cell proliferation.

    PubMed

    Fernandéz-Taboada, Enrique; Moritz, Sören; Zeuschner, Dagmar; Stehling, Martin; Schöler, Hans R; Saló, Emili; Gentile, Luca

    2010-04-01

    Planarians are an ideal model system to study in vivo the dynamics of adult pluripotent stem cells. However, our knowledge of the factors necessary for regulating the 'stemness' of the neoblasts, the adult stem cells of planarians, is sparse. Here, we report on the characterization of the first planarian member of the LSm protein superfamily, Smed-SmB, which is expressed in stem cells and neurons in Schmidtea mediterranea. LSm proteins are highly conserved key players of the splicing machinery. Our study shows that Smed-SmB protein, which is localized in the nucleus and the chromatoid body of stem cells, is required to safeguard the proliferative ability of the neoblasts. The chromatoid body, a cytoplasmatic ribonucleoprotein complex, is an essential regulator of the RNA metabolism required for the maintenance of metazoan germ cells. However, planarian neoblasts and neurons also rely on its functions. Remarkably, Smed-SmB dsRNA-mediated knockdown results in a rapid loss of organization of the chromatoid body, an impairment of the ability to post-transcriptionally process the transcripts of Smed-CycB, and a severe proliferative failure of the neoblasts. This chain of events leads to a quick depletion of the neoblast pool, resulting in a lethal phenotype for both regenerating and intact animals. In summary, our results suggest that Smed-SmB is an essential component of the chromatoid body, crucial to ensure a proper RNA metabolism and essential for stem cell proliferation. PMID:20215344

  14. Diversity, specificity and speciation in larval Diplostomidae (Platyhelminthes: Digenea) in the eyes of freshwater fish, as revealed by DNA barcodes.

    PubMed

    Locke, Sean A; Al-Nasiri, Fatima S; Caffara, Monica; Drago, Fabiana; Kalbe, Martin; Lapierre, Angela Rose; McLaughlin, J Daniel; Nie, Pin; Overstreet, Robin M; Souza, Geza T R; Takemoto, Ricardo M; Marcogliese, David J

    2015-11-01

    Larvae (metacercariae) in some species of Diplostomidae (Platyhelminthes: Digenea) inhabit fish eyes and are difficult to identify to species based on morphology. DNA barcoding has clarified the diversity and life cycles of diplostomids in North America, Europe and Africa, but has seldom been used in parasites sampled in large numbers or at large spatial scales. Here, distance-based analysis of cytochrome c oxidase 1 barcodes and, in some specimens, internal transcribed spacer (ITS-1, 5.8S, ITS-2) sequences was performed for over 2000 diplostomids from Africa, the Middle East, Europe, Asia and the Americas. Fifty-two species of Diplostomum, Tylodelphys and Austrodiplostomum (Digenea: Diplostomidae) were distinguished. The 52 species comprise 12 identified species, six species in two species complexes and 34 putative species, and 33/52 had been delineated in previous studies. Most (23/40) of the unidentified, putative species distinguished by cytochrome c oxidase 1 distances were supported by at least one additional line of evidence. As the intensity of sampling of the 52 species increased, variation in cytochrome c oxidase 1 decreased between and increased within species, while the spatial scale at which species were sampled had no effect. Nonetheless, variation between species always exceeded variation within species. New life-cycle linkages, geographic and host records, and genetic data were recorded in several species, including Tylodelphys jenynsiae, Tylodelphys immer and Diplostomum ardeae. Species of Diplostomum inhabiting the lens are less host-specific and less numerous than those infecting other tissues, suggesting that reduced immune activity in the lens has influenced rates of speciation. PMID:26276524

  15. A LIM-homeobox gene is required for differentiation of Wnt-expressing cells at the posterior end of the planarian body.

    PubMed

    Hayashi, Tetsutaro; Motoishi, Minako; Yazawa, Shigenobu; Itomi, Kazu; Tanegashima, Chiharu; Nishimura, Osamu; Agata, Kiyokazu; Tarui, Hiroshi

    2011-09-01

    Planarians have high regenerative ability, which is dependent on pluripotent adult somatic stem cells called neoblasts. Recently, canonical Wnt/β-catenin signaling was shown to be required for posterior specification, and Hedgehog signaling was shown to control anterior-posterior polarity via activation of the Djwnt1/P-1 gene at the posterior end of planarians. Thus, various signaling molecules play an important role in planarian stem cell regulation. However, the molecular mechanisms directly involved in stem cell differentiation have remained unclear. Here, we demonstrate that one of the planarian LIM-homeobox genes, Djislet, is required for the differentiation of Djwnt1/P-1-expressing cells from stem cells at the posterior end. RNA interference (RNAi)-treated planarians of Djislet [Djislet(RNAi)] show a tail-less phenotype. Thus, we speculated that Djislet might be involved in activation of the Wnt signaling pathway in the posterior blastema. When we carefully examined the expression pattern of Djwnt1/P-1 by quantitative real-time PCR during posterior regeneration, we found two phases of Djwnt1/P-1 expression: the first phase was detected in the differentiated cells in the old tissue in the early stage of regeneration and then a second phase was observed in the cells derived from stem cells in the posterior blastema. Interestingly, Djislet is expressed in stem cell-derived DjPiwiA- and Djwnt1/P-1-expressing cells, and Djislet(RNAi) only perturbed the second phase. Thus, we propose that Djislet might act to trigger the differentiation of cells expressing Djwnt1/P-1 from stem cells. PMID:21828095

  16. The Mi-2-like Smed-CHD4 gene is required for stem cell differentiation in the planarian Schmidtea mediterranea.

    PubMed

    Scimone, M Lucila; Meisel, Joshua; Reddien, Peter W

    2010-04-01

    Freshwater planarians are able to regenerate any missing part of their body and have extensive tissue turnover because of the action of dividing cells called neoblasts. Neoblasts provide an excellent system for in vivo study of adult stem cell biology. We identified the Smed-CHD4 gene, which is predicted to encode a chromatin-remodeling protein similar to CHD4/Mi-2 proteins, as required for planarian regeneration and tissue homeostasis. Following inhibition of Smed-CHD4 with RNA interference (RNAi), neoblast numbers were initially normal, despite an inability of the animals to regenerate. However, the proliferative response of neoblasts to amputation or growth stimulation in Smed-CHD4(RNAi) animals was diminished. Smed-CHD4(RNAi) animals displayed a dramatic reduction in the numbers of certain neoblast progeny cells. Smed-CHD4 was required for the formation of these neoblast progeny cells. Together, these results indicate that Smed-CHD4 is required for neoblasts to produce progeny cells committed to differentiation in order to control tissue turnover and regeneration and suggest a crucial role for CHD4 proteins in stem cell differentiation. PMID:20223763

  17. Inheritance of a Nuclear PIWI from Pluripotent Stem Cells by Somatic Descendants Ensures Differentiation by Silencing Transposons in Planarian.

    PubMed

    Shibata, Norito; Kashima, Makoto; Ishiko, Taisuke; Nishimura, Osamu; Rouhana, Labib; Misaki, Kazuyo; Yonemura, Shigenobu; Saito, Kuniaki; Siomi, Haruhiko; Siomi, Mikiko C; Agata, Kiyokazu

    2016-05-01

    Differentiation of pluripotent stem cells (PSCs) requires transposon silencing throughout the process. PIWIs, best known as key factors in germline transposon silencing, are also known to act in somatic differentiation of planarian PSCs (neoblasts). However, how PIWIs control the latter process remains elusive. Here, using Dugesia japonica, we show that a nuclear PIWI, DjPiwiB, was bound to PIWI-interacting RNAs (generally key mediators of PIWI-dependent transposon silencing), and was detected in not only neoblasts but also their descendant somatic cells, which do not express piwi. In contrast, cytoplasmic DjPiwiA and DjPiwiC were detected only in neoblasts, in accord with their transcription there. DjPiwiB was indispensable for regeneration, but dispensable for transposon silencing in neoblasts. However, transposons were derepressed at the onset of differentiation in DjPiwiB-knockdown planarians. Thus, DjPiwiB appears to be inherited by descendant somatic cells of neoblasts to ensure transposon silencing in those cells, which are unable to produce PIWI proteins. PMID:27165555

  18. Wnt/Notum spatial feedback inhibition controls neoblast differentiation to regulate reversible growth of the planarian brain.

    PubMed

    Hill, Eric M; Petersen, Christian P

    2015-12-15

    Mechanisms determining final organ size are poorly understood. Animals undergoing regeneration or ongoing adult growth are likely to require sustained and robust mechanisms to achieve and maintain appropriate sizes. Planarians, well known for their ability to undergo whole-body regeneration using pluripotent adult stem cells of the neoblast population, can reversibly scale body size over an order of magnitude by controlling cell number. Using quantitative analysis, we showed that after injury planarians perfectly restored brain:body proportion by increasing brain cell number through epimorphosis or decreasing brain cell number through tissue remodeling (morphallaxis), as appropriate. We identified a pathway controlling a brain size set-point that involves feedback inhibition between wnt11-6/wntA/wnt4a and notum, encoding conserved antagonistic signaling factors expressed at opposite brain poles. wnt11-6/wntA/wnt4a undergoes feedback inhibition through canonical Wnt signaling but is likely to regulate brain size in a non-canonical pathway independently of beta-catenin-1 and APC. Wnt/Notum signaling tunes numbers of differentiated brain cells in regenerative growth and tissue remodeling by influencing the abundance of brain progenitors descended from pluripotent stem cells, as opposed to regulating cell death. These results suggest that the attainment of final organ size might be accomplished by achieving a balance of positional signaling inputs that regulate the rates of tissue production. PMID:26525673

  19. Identification of HECT E3 ubiquitin ligase family genes involved in stem cell regulation and regeneration in planarians.

    PubMed

    Henderson, Jordana M; Nisperos, Sean V; Weeks, Joi; Ghulam, Mahjoobah; Marín, Ignacio; Zayas, Ricardo M

    2015-08-15

    E3 ubiquitin ligases constitute a large family of enzymes that modify specific proteins by covalently attaching ubiquitin polypeptides. This post-translational modification can serve to regulate protein function or longevity. In spite of their importance in cell physiology, the biological roles of most ubiquitin ligases remain poorly understood. Here, we analyzed the function of the HECT domain family of E3 ubiquitin ligases in stem cell biology and tissue regeneration in planarians. Using bioinformatic searches, we identified 17 HECT E3 genes that are expressed in the Schmidtea mediterranea genome. Whole-mount in situ hybridization experiments showed that HECT genes were expressed in diverse tissues and most were expressed in the stem cell population (neoblasts) or in their progeny. To investigate the function of all HECT E3 ligases, we inhibited their expression using RNA interference (RNAi) and determined that orthologs of huwe1, wwp1, and trip12 had roles in tissue regeneration. We show that huwe1 RNAi knockdown led to a significant expansion of the neoblast population and death by lysis. Further, our experiments showed that wwp1 was necessary for both neoblast and intestinal tissue homeostasis as well as uncovered an unexpected role of trip12 in posterior tissue specification. Taken together, our data provide insights into the roles of HECT E3 ligases in tissue regeneration and demonstrate that planarians will be a useful model to evaluate the functions of E3 ubiquitin ligases in stem cell regulation. PMID:25956527

  20. The Mi-2-like Smed-CHD4 gene is required for stem cell differentiation in the planarian Schmidtea mediterranea

    PubMed Central

    Scimone, M. Lucila; Meisel, Joshua; Reddien, Peter W.

    2010-01-01

    Freshwater planarians are able to regenerate any missing part of their body and have extensive tissue turnover because of the action of dividing cells called neoblasts. Neoblasts provide an excellent system for in vivo study of adult stem cell biology. We identified the Smed-CHD4 gene, which is predicted to encode a chromatin-remodeling protein similar to CHD4/Mi-2 proteins, as required for planarian regeneration and tissue homeostasis. Following inhibition of Smed-CHD4 with RNA interference (RNAi), neoblast numbers were initially normal, despite an inability of the animals to regenerate. However, the proliferative response of neoblasts to amputation or growth stimulation in Smed-CHD4(RNAi) animals was diminished. Smed-CHD4(RNAi) animals displayed a dramatic reduction in the numbers of certain neoblast progeny cells. Smed-CHD4 was required for the formation of these neoblast progeny cells. Together, these results indicate that Smed-CHD4 is required for neoblasts to produce progeny cells committed to differentiation in order to control tissue turnover and regeneration and suggest a crucial role for CHD4 proteins in stem cell differentiation. PMID:20223763

  1. Modeling Planarian Regeneration: A Primer for Reverse-Engineering the Worm

    PubMed Central

    Lobo, Daniel; Beane, Wendy S.; Levin, Michael

    2012-01-01

    A mechanistic understanding of robust self-assembly and repair capabilities of complex systems would have enormous implications for basic evolutionary developmental biology as well as for transformative applications in regenerative biomedicine and the engineering of highly fault-tolerant cybernetic systems. Molecular biologists are working to identify the pathways underlying the remarkable regenerative abilities of model species that perfectly regenerate limbs, brains, and other complex body parts. However, a profound disconnect remains between the deluge of high-resolution genetic and protein data on pathways required for regeneration, and the desired spatial, algorithmic models that show how self-monitoring and growth control arise from the synthesis of cellular activities. This barrier to progress in the understanding of morphogenetic controls may be breached by powerful techniques from the computational sciences—using non-traditional modeling approaches to reverse-engineer systems such as planaria: flatworms with a complex bodyplan and nervous system that are able to regenerate any body part after traumatic injury. Currently, the involvement of experts from outside of molecular genetics is hampered by the specialist literature of molecular developmental biology: impactful collaborations across such different fields require that review literature be available that presents the key functional capabilities of important biological model systems while abstracting away from the often irrelevant and confusing details of specific genes and proteins. To facilitate modeling efforts by computer scientists, physicists, engineers, and mathematicians, we present a different kind of review of planarian regeneration. Focusing on the main patterning properties of this system, we review what is known about the signal exchanges that occur during regenerative repair in planaria and the cellular mechanisms that are thought to underlie them. By establishing an engineering

  2. A wound-induced Wnt expression program controls planarian regeneration polarity.

    PubMed

    Petersen, Christian P; Reddien, Peter W

    2009-10-01

    Regeneration requires specification of the identity of new tissues to be made. Whether this process relies only on intrinsic regulative properties of regenerating tissues or whether wound signaling provides input into tissue repatterning is not known. The head-versus-tail regeneration polarity decision in planarians, which requires Wnt signaling, provides a paradigm to study the process of tissue identity specification during regeneration. The Smed-wntP-1 gene is required for regeneration polarity and is expressed at the posterior pole of intact animals. Surprisingly, wntP-1 was expressed at both anterior- and posterior-facing wounds rapidly after wounding. wntP-1 expression was induced by all types of wounds examined, regardless of whether wounding prompted tail regeneration. Regeneration polarity was found to require new expression of wntP-1. Inhibition of the wntP-2 gene enhanced the polarity phenotype due to wntP-1 inhibition, with new expression of wntP-2 in regeneration occurring subsequent to expression of wntP-1 and localized only to posterior-facing wounds. New expression of wntP-2 required wound-induced wntP-1. Finally, wntP-1 and wntP-2 expression changes occurred even in the absence of neoblast stem cells, which are required for regeneration, suggesting that the role of these genes in polarity is independent of and instructive for tail formation. These data indicate that wound-induced input is involved in resetting the normal polarized features of the body axis during regeneration. PMID:19805089

  3. Modeling planarian regeneration: a primer for reverse-engineering the worm.

    PubMed

    Lobo, Daniel; Beane, Wendy S; Levin, Michael

    2012-01-01

    A mechanistic understanding of robust self-assembly and repair capabilities of complex systems would have enormous implications for basic evolutionary developmental biology as well as for transformative applications in regenerative biomedicine and the engineering of highly fault-tolerant cybernetic systems. Molecular biologists are working to identify the pathways underlying the remarkable regenerative abilities of model species that perfectly regenerate limbs, brains, and other complex body parts. However, a profound disconnect remains between the deluge of high-resolution genetic and protein data on pathways required for regeneration, and the desired spatial, algorithmic models that show how self-monitoring and growth control arise from the synthesis of cellular activities. This barrier to progress in the understanding of morphogenetic controls may be breached by powerful techniques from the computational sciences-using non-traditional modeling approaches to reverse-engineer systems such as planaria: flatworms with a complex bodyplan and nervous system that are able to regenerate any body part after traumatic injury. Currently, the involvement of experts from outside of molecular genetics is hampered by the specialist literature of molecular developmental biology: impactful collaborations across such different fields require that review literature be available that presents the key functional capabilities of important biological model systems while abstracting away from the often irrelevant and confusing details of specific genes and proteins. To facilitate modeling efforts by computer scientists, physicists, engineers, and mathematicians, we present a different kind of review of planarian regeneration. Focusing on the main patterning properties of this system, we review what is known about the signal exchanges that occur during regenerative repair in planaria and the cellular mechanisms that are thought to underlie them. By establishing an engineering-like style

  4. Weak extremely-low-frequency magnetic field-induced regeneration anomalies in the planarian, Dugesia tigrina

    SciTech Connect

    Jenrow, K.A.; Smith, C.H.; Liboff, A.R.

    1996-12-31

    The authors recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC magnetic fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. The authors report here, in a parallel series of investigations on the same model system, that the incidence of regeneration anomalies presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz magnetic fields, with peak intensities ranging between 1.0 and 80.0 {micro}T. These anomalies often culminate in the complete disaggregation of the organism. Similar to regeneration rate effects, the incidence of regeneration anomalies is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied magnetic field vectors. However, unlike the regeneration rate effects, the AC magnetic field alone, in the absence of any measurable DC field, is capable of producing these anomalies. Moreover, the incidence of regeneration anomalies follows a clear dose-response relationship as a function of AC magnetic field intensity, with the threshold for induced electric field intensity estimated at 5 {micro} V/m. The addition of either 51.1 or 78.4 {micro}T DC magnetic fields, applied in parallel combination with the AC field, enhances the appearance of anomalies relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas the previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration anomalies reported here appear to result primarily from Faraday induction coupling.

  5. A Chemical Genetics Approach Reveals H,K-ATPase-Mediated Membrane Voltage is Required for Planarian Head Regeneration

    PubMed Central

    Beane, Wendy Scott; Morokuma, Junji; Adams, Dany Spencer; Levin, Michael

    2012-01-01

    SUMMARY Biophysical signaling is required for both embryonic polarity and regenerative outgrowth. Exploiting endogenous ion transport for regenerative therapies will require direct regulation of membrane voltage. Here, we develop a pharmacological method to target ion transporters, uncovering a novel role for membrane voltage as a key regulator of anterior polarity in regenerating planaria. Utilizing the highly specific inhibitor, SCH-28080, our data reveal that H+,K+-ATPase-mediated membrane depolarization is essential for anterior gene expression and brain induction. H+,K+-ATPase-independent manipulation of membrane potential with ivermectin confirms that depolarization drives head formation, even at posterior-facing wounds. Using this chemical genetics approach, we demonstrate that membrane voltage controls head-vs.-tail identity during planarian regeneration. Our data suggest well-characterized drugs (already approved for human use) might be exploited to control adult stem cell-driven pattern formation during the regeneration of complex structures. PMID:21276941

  6. Molecular characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from goats in the western part of India by LSU of nuclear ribosomal DNA.

    PubMed

    Kumar, Ashwani; Chaudhary, Anshu; Verma, Chandni; Singh, Hridaya Shanker

    2014-12-01

    The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India. PMID:25548426

  7. The CCR4-NOT complex mediates deadenylation and degradation of stem cell mRNAs and promotes planarian stem cell differentiation.

    PubMed

    Solana, Jordi; Gamberi, Chiara; Mihaylova, Yuliana; Grosswendt, Stefanie; Chen, Chen; Lasko, Paul; Rajewsky, Nikolaus; Aboobaker, A Aziz

    2013-01-01

    Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology. PMID:24367277

  8. The CCR4-NOT Complex Mediates Deadenylation and Degradation of Stem Cell mRNAs and Promotes Planarian Stem Cell Differentiation

    PubMed Central

    Solana, Jordi; Gamberi, Chiara; Mihaylova, Yuliana; Grosswendt, Stefanie; Chen, Chen; Lasko, Paul; Rajewsky, Nikolaus; Aboobaker, A. Aziz

    2013-01-01

    Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology. PMID:24367277

  9. Transcription factors lhx1/5-1 and pitx are required for the maintenance and regeneration of serotonergic neurons in planarians.

    PubMed

    Currie, Ko W; Pearson, Bret J

    2013-09-01

    In contrast to most adult organisms, freshwater planarians can regenerate any injured body part, including their entire nervous system. This allows for the analysis of genes required for both the maintenance and regeneration of specific neural subtypes. In addition, the loss of specific neural subtypes may uncover previously unknown behavioral roles for that neural population in the context of the adult animal. Here we show that two homeodomain transcription factor homologs, Smed-lhx1/5-1 and Smed-pitx, are required for the maintenance and regeneration of serotonergic neurons in planarians. When either lhx1/5-1 or pitx was knocked down by RNA interference, the expression of multiple canonical markers for serotonergic neurons was lost. Surprisingly, the loss of serotonergic function uncovered a role for these neurons in the coordination of motile cilia on the ventral epidermis of planarians that are required for their nonmuscular gliding locomotion. Finally, we show that in addition to its requirement in serotonergic neurons, Smed-pitx is required for proper midline patterning during regeneration, when it is required for the expression of the midline-organizing molecules Smed-slit in the anterior and Smed-wnt1 in the posterior. PMID:23903188

  10. First report of the genus Cratera (Platyhelminthes, Geoplanidae) in Argentina, with description of a new species and comments on the species of the genus.

    PubMed

    Negrete, Lisandro; Brusa, Francisco

    2016-01-01

    A new species of land planarians of the genus Cratera is described. Cratera viridimaculata sp. n. was recorded in the Atlantic Forest Ecoregion, in north-eastern Argentina, and represents the first report of the genus Cratera outside Brazil. The new species is about 50 mm in length and externally characterized by a color pattern consisting of a light green olive pigmentation on the dorsum, stippled with dark gray fine spots, and dorsal eyes. Other features regarding the internal anatomy are the presence of a glandular margin, Cutaneous Muscular Index (CMI) of 10-13%, pharynx cylindrical, prostatic vesicle extrabulbar, tubular and C-shaped, with a proximal bifurcated portion, penis papilla protrusible with ejaculatory duct widened in its distal portion, and female atrium funnel-shaped. The new species is compared and discussed with its congeners. PMID:27587974