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NCBI: db=pubmed; Term=(((((((((echinoderm) AND developmental biology) OR strongylocentrotus purpuratus) OR patiria miniata) OR lytechinus variegatus) OR eucidaris tribuloides) OR parastichopus parvimensis) OR ophiothrix apiculata) OR allocentrotus fragilis) OR strongylocentrotus franciscanus AND ( ( Humans[Mesh] OR Animals[Mesh:noexp] ) ) AND ("last 5 years"[PDat])
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Developmental origin of peripheral ciliary band neurons in the sea urchin embryo.

Wed, 10/21/2020 - 11:34
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Developmental origin of peripheral ciliary band neurons in the sea urchin embryo.

Dev Biol. 2020 03 15;459(2):72-78

Authors: Slota LA, Miranda E, Peskin B, McClay DR

Abstract
In the sea urchin larva, most neurons lie within an ectodermal region called the ciliary band. Our understanding of the mechanisms of specification and patterning of these peripheral ciliary band neurons is incomplete. Here, we first examine the gene regulatory landscape from which this population of neural progenitors arise in the neuroectoderm. We show that ciliary band neural progenitors first appear in a bilaterally symmetric pattern on the lateral edges of chordin expression in the neuroectoderm. Later in development, these progenitors appear in a salt-and-pepper pattern in the ciliary band where they express soxC, and prox, which are markers of neural specification, and begin to express synaptotagminB, a marker of differentiated neurons. We show that the ciliary band expresses the acid sensing ion channel gene asicl, which suggests that ciliary band neurons control the larva's ability to discern touch sensitivity. Using a chemical inhibitor of MAPK signaling, we show that this signaling pathway is required for proper specification and patterning of ciliary band neurons. Using live imaging, we show that these neural progenitors undergo small distance migrations in the embryo. We then show that the normal swimming behavior of the larvae is compromised if the neurogenesis pathway is perturbed. The developmental sequence of ciliary band neurons is very similar to that of neural crest-derived sensory neurons in vertebrates and may provide insights into the evolution of sensory neurons in deuterostomes.

PMID: 31881199 [PubMed - indexed for MEDLINE]

Categories: pubmed

Combined Effects of Diatom-Derived Oxylipins on the Sea Urchin Paracentrotus lividus.

Wed, 10/07/2020 - 06:52
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Combined Effects of Diatom-Derived Oxylipins on the Sea Urchin Paracentrotus lividus.

Int J Mol Sci. 2020 Jan 22;21(3):

Authors: Esposito R, Ruocco N, Albarano L, Ianora A, Manfra L, Libralato G, Costantini M

Abstract
Oxylipins are diatom-derived secondary metabolites, deriving from the oxidation of polyunsatured fatty acids that are released from cell membranes after cell damage or senescence of these single-celled algae. Previous results revealed harmful toxic effects of polyunsaturated aldehydes (PUAs) and hydroxyacids (HEPEs) on sea urchin Paracentrotus lividus embryonic development by testing individual compounds and mixtures of the same chemical group. Here, we investigated the combined effects of these compounds on sea urchin development at the morphological and molecular level for the first time. Our results demonstrated that oxylipin mixtures had stronger effects on sea urchin embryos compared with individual compounds, confirming that PUAs induce malformations and HEPEs cause developmental delay. This harmful effect was also confirmed by molecular analysis. Twelve new genes, involved in stress response and embryonic developmental processes, were isolated from the sea urchin P. lividus; these genes were found to be functionally interconnected with 11 genes already identified as a stress response of P. lividus embryos to single oxylipins. The expression levels of most of the analyzed genes targeted by oxylipin mixtures were involved in stress, skeletogenesis, development/differentiation, and detoxification processes. This work has important ecological implications, considering that PUAs and HEPEs represent the most abundant oxylipins in bloom-forming diatoms, opening new perspectives in understanding the molecular pathways activated by sea urchins exposed to diatom oxylipins.

PMID: 31979078 [PubMed - indexed for MEDLINE]

Categories: pubmed

Zinc protection of fertilized eggs is an ancient feature of sexual reproduction in animals.

Wed, 09/09/2020 - 03:14
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Zinc protection of fertilized eggs is an ancient feature of sexual reproduction in animals.

PLoS Biol. 2020 07;18(7):e3000811

Authors: Wozniak KL, Bainbridge RE, Summerville DW, Tembo M, Phelps WA, Sauer ML, Wisner BW, Czekalski ME, Pasumarthy S, Hanson ML, Linderman MB, Luu CH, Boehm ME, Sanders SM, Buckley KM, Bain DJ, Nicotra ML, Lee MT, Carlson AE

Abstract
One of the earliest and most prevalent barriers to successful reproduction is polyspermy, or fertilization of an egg by multiple sperm. To prevent these supernumerary fertilizations, eggs have evolved multiple mechanisms. It has recently been proposed that zinc released by mammalian eggs at fertilization may block additional sperm from entering. Here, we demonstrate that eggs from amphibia and teleost fish also release zinc. Using Xenopus laevis as a model, we document that zinc reversibly blocks fertilization. Finally, we demonstrate that extracellular zinc similarly disrupts early embryonic development in eggs from diverse phyla, including Cnidaria, Echinodermata, and Chordata. Our study reveals that a fundamental strategy protecting human eggs from fertilization by multiple sperm may have evolved more than 650 million years ago.

PMID: 32735558 [PubMed - indexed for MEDLINE]

Categories: pubmed