Non-native brittle star interactions with native octocoral epizoites: an endemic benthic ctenophore in peril?

2021 ◽  
Vol 168 (9) ◽  
Author(s):  
Peter W. Glynn ◽  
Brian Coffman ◽  
Kyle Dettloff ◽  
Joshua Dominguez ◽  
Phillip R. Gillette ◽  
...  
Keyword(s):  
Brittle Star

Early ossicle growth in the regenerating disc of a brittle star

1994 ◽  
Vol 52 ◽  
pp. 364-365
Author(s):  
M. Shlepr ◽  
R. L. Turner
Keyword(s):  
Cell Membrane ◽  
Light Microscopy ◽  
De Novo ◽  
Current Model ◽  
Syncytium Formation ◽  
Brittle Star ◽  
Intracellular Location ◽  
Limited Volume ◽  
Tissue Calcification

Calcification in the echinoderms occurs within a limited-volume cavity enclosed by cytoplasmic extensions of the mineral depositing cells, the sclerocytes. The current model of this process maintains that the sheath formed from these cytoplasmic extensions is syncytial. Prior studies indicate that syncytium formation might be dependent on sclerocyte density and not required for calcification. This model further envisions that ossicles formed de novo nucleate and grow intracellularly until the ossicle effectively outgrows the vacuole. Continued ossicle growth occurs within the sheath but external to the cell membrane. The initial intracellular location has been confirmed only for elements of the echinoid tooth.The regenerating aboral disc integument of ophiophragmus filograneus was used to test the current echinoderm calcification model. This tissue is free of calcite fragments, thus avoiding questions of cellular engulfment, and ossicles are formed de novo. The tissue calcification pattern was followed by light microscopy in both living and fixed preparations.

scholarly journals Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Laura Piovani ◽  
Anna Czarkwiani ◽  
Cinzia Ferrario ◽  
Michela Sugni ◽  
Paola Oliveri
Keyword(s):  
Molecular Mechanisms ◽  
Close Contact ◽  
Skeletal Development ◽  
Morphological Differentiation ◽  
Brittle Star ◽  
Marker Genes ◽  
Body Parts ◽  
Coelomic Cavity ◽  
Expression Of Genes ◽  
Skeletal Regeneration

Abstract Background Regeneration is the ability to re-grow body parts or tissues after trauma, and it is widespread across metazoans. Cells involved in regeneration can arise from a pool of undifferentiated proliferative cells or be recruited from pre-existing differentiated tissues. Both mechanisms have been described in different phyla; however, the cellular and molecular mechanisms employed by different animals to restore lost tissues as well as the source of cells involved in regeneration remain largely unknown. Echinoderms are a clade of deuterostome invertebrates that show striking larval and adult regenerative abilities in all extant classes. Here, we use the brittle star Amphiura filiformis to investigate the origin and differentiation of cells involved in skeletal regeneration using a combination of microscopy techniques and molecular markers. Results Our ultrastructural analyses at different regenerative stages identify a population of morphologically undifferentiated cells which appear in close contact with the proliferating epithelium of the regenerating aboral coelomic cavity. These cells express skeletogenic marker genes, such as the transcription factor alx1 and the differentiation genes c-lectin and msp130L, and display a gradient of morphological differentiation from the aboral coelomic cavity towards the epidermis. Cells closer to the epidermis, which are in contact with developing spicules, have the morphology of mature skeletal cells (sclerocytes), and express several skeletogenic transcription factors and differentiation genes. Moreover, as regeneration progresses, sclerocytes show a different combinatorial expression of genes in various skeletal elements. Conclusions We hypothesize that sclerocyte precursors originate from the epithelium of the proliferating aboral coelomic cavity. As these cells migrate towards the epidermis, they differentiate and start secreting spicules. Moreover, our study shows that molecular and cellular processes involved in skeletal regeneration resemble those used during skeletal development, hinting at a possible conservation of developmental programmes during adult regeneration. Finally, we highlight that many genes involved in echinoderm skeletogenesis also play a role in vertebrate skeleton formation, suggesting a possible common origin of the deuterostome endoskeleton pathway.

scholarly journals An Untethered Brittle Star-Inspired Soft Robot for Closed-Loop Underwater Locomotion

2020 ◽  
Author(s):  
Zach J. Patterson ◽  
Andrew P. Sabelhaus ◽  
Keene Chin ◽  
Tess Hellebrekers ◽  
Carmel Majidi
Keyword(s):  
Closed Loop ◽  
Brittle Star ◽  
Soft Robot

scholarly journals Phylogeography of the Brittle Star Ophiura sarsii Lütken, 1855 (Echinodermata: Ophiuroidea) from the Barents Sea and East Atlantic

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 40
Author(s):  
Evgeny Genelt-Yanovskiy ◽  
Yixuan Li ◽  
Ekaterina Stratanenko ◽  
Natalia Zhuravleva ◽  
Natalia Strelkova ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Barents Sea ◽  
Haplotype Diversity ◽  
Brittle Star ◽  
The Arctic ◽  
Coi Gene ◽  
High Genetic Diversity ◽  
Svalbard Archipelago ◽  
Mitochondrial Coi ◽  
The Barents Sea

Ophiura sarsii is a common brittle star species across the Arctic and Sub-Arctic regions of the Atlantic and the Pacific oceans. Ophiurasarsii is among the dominant echinoderms in the Barents Sea. We studied the genetic diversity of O.sarsii by sequencing the 548 bp fragment of the mitochondrial COI gene. Ophiurasarsii demonstrated high genetic diversity in the Barents Sea. Both major Atlantic mtDNA lineages were present in the Barents Sea and were evenly distributed between the northern waters around Svalbard archipelago and the southern part near Murmansk coast of Kola Peninsula. Both regions, and other parts of the O.sarsii range, were characterized by high haplotype diversity with a significant number of private haplotypes being mostly satellites to the two dominant haplotypes, each belonging to a different mtDNA clade. Demographic analyses indicated that the demographic and spatial expansion of O.sarsii in the Barents Sea most plausibly has started in the Bølling–Allerød interstadial during the deglaciation of the western margin of the Barents Sea.

scholarly journals A Cytotoxic Porphyrin from North Pacific Brittle Star Ophiura sarsii

Marine Drugs ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 11
Author(s):  
Antonina Klimenko ◽  
Robin Huber ◽  
Laurence Marcourt ◽  
Estelle Chardonnens ◽  
Alexey Koval ◽  
...  
Keyword(s):  
North Pacific ◽  
Ethanol Extract ◽  
2D Nmr ◽  
Brittle Star ◽  
Inert Material ◽  
Cancer Therapies ◽  
The North ◽  
Anti Cancer ◽  
One Step ◽  
The North Pacific

Triple-negative breast cancer (TNBC) represents the deadliest form of gynecological tumors currently lacking targeted therapies. The ethanol extract of the North Pacific brittle star Ophiura sarsii presented promising anti-TNBC activities. After elimination of the inert material, the active extract was submitted to a bioguided isolation approach using high-resolution semipreparative HPLC-UV, resulting in one-step isolation of an unusual porphyrin derivative possessing strong cytotoxic activity. HRMS and 2D NMR resulted in the structure elucidation of the compound as (3S,4S)-14-Ethyl-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid. Never identified before in Ophiuroidea, porphyrins have found broad applications as photosensitizers in the anticancer photodynamic therapy. The simple isolation of a cytotoxic porphyrin from an abundant brittle star species we describe here may pave the way for novel natural-based developments of targeted anti-cancer therapies.

scholarly journals The complex simplicity of the brittle star nervous system

2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Olga Zueva ◽  
Maleana Khoury ◽  
Thomas Heinzeller ◽  
Daria Mashanova ◽  
Vladimir Mashanov
Keyword(s):  
Nervous System ◽  
Brittle Star

Descriptive and illustrated diagnosis of Ophiuroidea fauna (Echinodermata) in the shallow waters of North-eastern Brazil

2015 ◽  
Vol 8 ◽  
Author(s):  
Fabilene Gomes Paim ◽  
Maria Cecília Guerrazzi ◽  
Michela Borges
Keyword(s):  
Brittle Star ◽  
Shallow Waters ◽  
Bottom Substrate ◽  
Eastern Brazil ◽  
North Eastern ◽  
Amphipholis Squamata ◽  
Biological Substrates ◽  
Almost All ◽  
First Time ◽  
Ophiocoma Echinata

In this study, we present descriptions, illustrations, comments, and bathymetric and geographic distributions of the brittle star species related to the estuary region of Camamu Bay, located in the State of Bahia, Brazil. The brittle star fauna lives on biological substrates, sand bottoms, mud and rubble in the Camamu Bay and comprises 12 species divided into five families. Almost all of them are common in the tropical and subtropical fauna of the regions of shallow water.Ophiophragmus filograneusis reported for the first time in Bahia, and nine other species are recorded for the first time in Camamu Bay:Amphipholis januarii, Amphipholis squamata, Ophiophragmus filograneus, Ophiostigma isocanthum,Ophioderma cinerea, Ophioderma januarii, Ophiactis lymani, Ophiactis savignyi andOphiocoma echinata.The results suggest that the ophiuroid assemblages are strongly affected by marine currents as well as by different kinds of bottom substrate.

Sign in / Sign up

Export Citation Format

Share Document