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Miquel Sureda-Gómez, José M Martín-Durán, Teresa Adell
The βcatenin-dependent Wnt pathway exerts multiple context-dependent roles in embryonic and adult tissues. In planarians, βcatenin-1 is thought to specify posterior identities through the generation of an anteroposterior gradient. However, the existence of such gradient has not been directly demonstrated. Here, we use a specific polyclonal antibody to demonstrate that nuclear βCATENIN-1 exists as an anteroposterior gradient from the pre-pharyngeal region to the tail of the planarian Schmidtea polychroa High levels in the posterior region steadily decrease towards the pre-pharyngeal region but then increase again in the head region...
October 13, 2016: Development
Zimei Dong, Yanqing Yuwen, Yingxu Sima, Yanping Dong, Huina Zhan, Guangwen Chen, Dezeng Liu
Planarians are the ideal models for studying eye development with the simple eye structure and exceptionally rapid regeneration. Here, we observed the eye morphogenesis, photophobic behavior, spectral sensitivity, and expression pattern of Djopsin in planarian Dugesia japonica. The results showed that: (1) Djopsin encoding the putative protein belonged to rhabdomeric opsins group and displayed a high conservation during animal evolution; (2) planarians displayed diverse photophobic response to different visible wavelength and were more sensitive to the light blue (495 nm) and yellow (635 nm); (3) the morphogenesis and functional recovery of eyes were related to the expression pattern of Djopsin during head regeneration; (4) Djopsin gene plays a major role in functional recovery during eyes regeneration and visual system maintenance in adult planarians...
September 14, 2016: Integrative Zoology
Daniel J Bach, Matthew Tenaglia, Debra L Baker, Sean Deats, Erica Montgomery, Oné R Pagán
Nicotine is one of the most addictive drugs abused by humans. Our laboratory and others have demonstrated that nicotine decreases motility and induces seizure-like behavior in planarians (pSLM, which are vigorous writhing and bending of the body) in a concentration-dependent manner. Nicotine also induces withdrawal-like behaviors in these worms. Cotinine is the major nicotine metabolite in humans, although it is not the final product of nicotine metabolism. Cotinine is mostly inactive in vertebrate nervous systems and is currently being explored as a molecule which possess most of nicotine's beneficial effects and few of its undesirable ones...
October 6, 2016: Neuroscience Letters
Rachel H Roberts-Galbraith, John L Brubacher, Phillip A Newmark
Planarians regenerate all body parts after injury, including the central nervous system (CNS). We capitalized on this distinctive trait and completed a gene expression-guided functional screen to identify factors that regulate diverse aspects of neural regeneration in Schmidtea mediterranea. Our screen revealed molecules that influence neural cell fates, support the formation of a major connective hub, and promote reestablishment of chemosensory behavior. We also identified genes that encode signaling molecules with roles in head regeneration, including some that are produced in a previously uncharacterized parenchymal population of cells...
September 9, 2016: ELife
Irving E Wang, Sylvain W Lapan, M Lucila Scimone, Thomas R Clandinin, Peter W Reddien
Hedgehog signaling is critical for vertebrate central nervous system (CNS) development, but its role in CNS biology in other organisms is poorly characterized. In the planarian Schmidtea mediterranea, hedgehog (hh) is expressed in medial cephalic ganglia neurons, suggesting a possible role in CNS maintenance or regeneration. We performed RNA sequencing of planarian brain tissue following RNAi of hh and patched (ptc), which encodes the Hh receptor. Two misregulated genes, intermediate filament-1 (if-1) and calamari (cali), were expressed in a previously unidentified non-neural CNS cell type...
September 9, 2016: ELife
Olivier Cochet-Escartin, Jason A Carter, Milena Chakraverti-Wuerthwein, Joydeb Sinha, Eva-Maria S Collins
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...
2016: Physical Biology
Constanza Vásquez-Doorman, Christian P Petersen
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...
June 2016: Regeneration
Suthira Owlarn, Kerstin Bartscherer
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...
June 2016: Regeneration
Marlena Piontek, Katarzyna Łuszczyńska, Hanna Lechów
In an area representative of a moderate climate zone (Lubuskie Province in Poland), mycological tests in over 270 flats demonstrated the occurrence of 82 species of moulds. Aspergillus versicolor Tiraboschi was often encountered on building partitions (frequency 4: frequently). The ability to synthesize the carcinogenic sterigmatocystin (ST) means that it poses a risk to humans and animals. Biotoxicological tests of biomasses of A. versicolor were conducted in the Microbiological and Toxicological Laboratory, using the planarians Dugesia tigrina (Girard)...
2016: International Journal of Environmental Research and Public Health
Lisandro Negrete, Francisco Brusa
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...
2016: ZooKeys
He-Cai Zhang, Chang-Ying Shi, Hui-Hui Yang, Guang-Wen Chen, De-Zeng Liu
The randomly amplified polymorphic DNA (RAPD) assay has been used to detect DNA alternation and mutation recently. However, the effectiveness of this method in detecting DNA damage in planarians, a model organism for assessing the toxicity of environmental pollutants is unknown. In the present study, RAPD assay was used to detect the DNA damage in planarians treated by the ionic liquid 1-octyl-3-methylimidazolium bromide ([C8mim]Br) for the first time. Among the 20 test RAPD primers, 13 primers with 60-70% GC content produced unique polymorphic band profiles...
August 26, 2016: Ecotoxicology and Environmental Safety
Lili Gao, Yu Han, Hongkuan Deng, Wenjing Hu, Hui Zhen, Na Li, Nianci Qin, Meihui Yan, Weiwei Wu, Baohua Liu, Bosheng Zhao, Qiuxiang Pang
Planarian, a representative of platyhelminthes, has strong regeneration ability and less complicated innate immune system. However, planarian immune system remains poorly understood. In this paper, a novel C-type lectin-like protein, namely, DjCTL was identified and characterized in Dugesia japonica. DjCTL was mainly expressed in the pharyngeal and epidermis and up-regulated upon the induction of lipopolysaccharide (LPS), peptidoglycan (PGN), Gram-positive and Gram-negative bacteria indicating that DjCTL may be involved in the immune responses...
August 23, 2016: Developmental and Comparative Immunology
Chen Wang, Xiao-Shuai Han, Fang-Fang Li, Shuang Huang, Yong-Wen Qin, Xian-Xian Zhao, Qing Jing
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...
2016: Cell Discovery
Natasha M Flores, Néstor J Oviedo, Julien Sage
The cellular turnover of adult tissues and injury-induced repair proceed through an exquisite integration of proliferation, differentiation, and survival signals that involve stem/progenitor cell populations, their progeny, and differentiated tissues. GATA factors are DNA binding proteins that control stem cells and the development of tissues by activating or repressing transcription. Here we examined the role of GATA transcription factors in Schmidtea mediterranea, a freshwater planarian that provides an excellent model to investigate gene function in adult stem cells, regeneration, and differentiation...
October 1, 2016: Developmental Biology
Machiko Teramoto, Tomomi Kudome-Takamatsu, Osamu Nishimura, Yang An, Makoto Kashima, Norito Shibata, Kiyokazu Agata
Planarian's strong regenerative ability is dependent on stem cells (called neoblasts) that are X-ray-sensitive and proliferative stem cells. In addition to neoblasts, another type of X-ray-sensitive cells was newly identified by recent research. Thus, planarian's X-ray-sensitive cells can be divided into at least two populations, Type 1 and Type 2, the latter corresponding to planarian's classically defined "neoblasts". Here, we show that Type 1 cells were distributed in the outer region (OR) immediately underneath the muscle layer at all axial levels from head to tail, while the Type 2 cells were distributed in a more internal region (IR) of the mesenchymal space at the axial levels from neck to tail...
September 2016: Development, Growth & Differentiation
Kai Lei, Hanh Thi-Kim Vu, Ryan D Mohan, Sean A McKinney, Chris W Seidel, Richard Alexander, Kirsten Gotting, Jerry L Workman, Alejandro Sánchez Alvarado
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)...
August 22, 2016: Developmental Cell
Stephen M King, Ramila S Patel-King
Planarian flatworms are carnivorous invertebrates with astounding regenerative properties. They have a ventral surface on which thousands of motile cilia are exposed to the extracellular environment. These beat in a synchronized manner against secreted mucus thereby propelling the animal forward. Similar to the nematode Caenorhabditis elegans, the planarian Schmidtea mediterranea is easy to maintain in the laboratory and is highly amenable to simple RNAi approaches through feeding with dsRNA. The methods are simple and robust, and the level of gene expression reduction that can be obtained is, in many cases, almost total...
2016: Methods in Molecular Biology
Jordi Solana, Manuel Irimia, Salah Ayoub, Marta Rodriguez Orejuela, Vera Zywitza, Marvin Jens, Javier Tapial, Debashish Ray, Quaid Morris, Timothy R Hughes, Benjamin J Blencowe, Nikolaus Rajewsky
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...
2016: ELife
Louise S Goupil, Sam L Ivry, Ivy Hsieh, Brian M Suzuki, Charles S Craik, Anthony J O'Donoghue, James H McKerrow
Proteases perform numerous vital functions in flatworms, many of which are likely to be conserved throughout the phylum Platyhelminthes. Within this phylum are several parasitic worms that are often poorly characterized due to their complex life-cycles and lack of responsiveness to genetic manipulation. The flatworm Schmidtea mediterranea, or planaria, is an ideal model organism to study the complex role of protein digestion due to its simple life cycle and amenability to techniques like RNA interference (RNAi)...
August 2016: PLoS Neglected Tropical Diseases
Fallon Durant, Daniel Lobo, Jennifer Hammelman, Michael Levin
Planaria are complex metazoans that repair damage to their bodies and cease remodeling when a correct anatomy has been achieved. This model system offers a unique opportunity to understand how large-scale anatomical homeostasis emerges from the activities of individual cells. Much progress has been made on the molecular genetics of stem cell activity in planaria. However, recent data also indicate that the global pattern is regulated by physiological circuits composed of ionic and neurotransmitter signaling...
April 2016: Regeneration
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