The function of simple prototypic eyes in two planarian species, the two ocular Girardia tigrina and the multiocular Polycelis tenuis, has been studied. When exposed to light, planarians display the light avoidance reaction known as negative phototaxis. This reaction has been investigated in intact animals and in head and tail fragments after their section in the course of eye regeneration. Specific features of the phototaxis reaction have been described in all groups of animals. The differences in light response recovery were shown between two planarian species and two regenerating fragments. No correlation between phototaxic reactions and the restoration of the eye structure, the number of eyes, the maturation of ganglion, the growth of regenerative blastema, and motor system has been found. The phototaxic response occurred two days after the recovery of the morphology of eyes and their connection with the brain. The participation of conserved and novel genes in early development of the eye function is discussed.
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Front Parasitol
March 2024
Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Flatworms depend on stem cells for continued tissue growth and renewal during their life cycles, making these cells valuable drug targets. While neoblasts are extensively characterized in the free-living planarian , and similar stem cells have been characterized in the trematode , their identification and characterization in cestodes is just emerging. Since stem cells are generally affected by irradiation, in this work we used this experimental approach to study the stem cells of the model cestode .
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Molecular Biosciences, Northwestern University; Evanston IL 60208.
The activation of progenitor cells near wound sites is a common feature of regeneration across species, but the conserved signaling mechanisms responsible for this step in whole-body regeneration are still incompletely understood. The acoel undergoes whole-body regeneration using Piwi+ pluripotent adult stem cells (neoblasts) that accumulate at amputation sites early in the regeneration process. The EGFR signaling pathway has broad roles in controlling proliferation, migration, differentiation, and cell survival across metazoans.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
College of Life Science, Henan Normal University, Xinxiang 453007, China. Electronic address:
The widespread application of quantum dots (QDs) in recent years has raised concerns about potential environmental and human health risks. Although the toxicity of cadmium telluride quantum dots (CdTe QDs) has been partially studied, their effects on stem cells, tissue regeneration, neurodevelopment, and neurobehavioral toxicity remain unclear. This study aimed to investigate the combined toxic effects and mechanisms of CdTe QDs on planarians at the individual, tissue, cellular, and molecular levels.
View Article and Find Full Text PDFNat Commun
January 2025
Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
Eye loss occurs convergently in numerous animal phyla as an adaptation to dark environments. We investigate the cave planarian Girardia multidiverticulata (Gm), a representative species of the Spiralian clade, to study mechanisms of eye loss. We found that Gm, which was previously described as an eyeless species, retains rudimentary and functional eyes.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia.
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