Ozpolat
B. Duygu
Ozpolat
B. Duygu
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ArticleSegment number threshold determines juvenile onset of germline cluster expansion in Platynereis dumerilii(Wiley, 2021-11-18) Kuehn, Emily ; Clausen, David S. ; Null, Ryan W. ; Metzger, Bria M. ; Willis, Amy D. ; Ozpolat, B. DuyguDevelopment of sexual characters and generation of gametes are tightly coupled with growth. Platynereis dumerilii is a marine annelid that has been used to study germline development and gametogenesis. P. dumerilii has germ cell clusters found across the body in the juvenile worms, and the clusters eventually form the gametes. Like other segmented worms, P. dumerilii grows by adding new segments at its posterior end. The number of segments reflect the growth state of the worms and therefore is a useful and measurable growth state metric to study the growth-reproduction crosstalk. To understand how growth correlates with progression of gametogenesis, we investigated germline development across several developmental stages. We discovered a distinct transition period when worms increase the number of germline clusters at a particular segment number threshold. Additionally, we found that keeping worms short in segment number, by manipulating environmental conditions or via amputations, supported a segment number threshold requirement for germline development. Finally, we asked if these clusters in P. dumerilii play a role in regeneration (as similar free-roaming cells are observed in Hydra and planarian regeneration) and found that the clusters were not required for regeneration in P. dumerilii, suggesting a strictly germline nature. Overall, these molecular analyses suggest a previously unidentified developmental transition dependent on the growth state of juvenile P. dumerilii leading to substantially increased germline expansion.
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ArticleSmall-molecule mimicry hunting strategy in the imperial cone snail, Conus imperialis(American Association for the Advancement of Science, 2021-03-12) Torres, Joshua P. ; Lin, Zhenjian ; Watkins, Maren ; Salcedo, Paula Flórez ; Baskin, Robert P. ; Elhabian, Shireen ; Safavi-Hemami, Helena ; Taylor, Dylan ; Tun, Jortan ; Concepcion, Gisela P. ; Saguil, Noel ; Yanagihara, Angel A. ; Fang, Yixin ; McArthur, Jeffrey R. ; Tae, Han-Shen ; Finol-Urdaneta, Rocio K. ; Ozpolat, B. Duygu ; Olivera, Baldomero M. ; Schmidt, Eric W.Venomous animals hunt using bioactive peptides, but relatively little is known about venom small molecules and the resulting complex hunting behaviors. Here, we explored the specialized metabolites from the venom of the worm-hunting cone snail, Conus imperialis. Using the model polychaete worm Platynereis dumerilii, we demonstrate that C. imperialis venom contains small molecules that mimic natural polychaete mating pheromones, evoking the mating phenotype in worms. The specialized metabolites from different cone snails are species-specific and structurally diverse, suggesting that the cones may adopt many different prey-hunting strategies enabled by small molecules. Predators sometimes attract prey using the prey’s own pheromones, in a strategy known as aggressive mimicry. Instead, C. imperialis uses metabolically stable mimics of those pheromones, indicating that, in biological mimicry, even the molecules themselves may be disguised, providing a twist on fake news in chemical ecology.
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ArticleCell lineage and cell cycling analyses of the 4d micromere using live imaging in the marine annelid Platynereis dumerilii(eLife, 2017-12-12) Ozpolat, B. Duygu ; Handberg-Thorsager, Mette ; Vervoort, Michel ; Balavoine, GuillaumeCell lineage, cell cycle, and cell fate are tightly associated in developmental processes, but in vivo studies at single-cell resolution showing the intricacies of these associations are rare due to technical limitations. In this study on the marine annelid Platynereis dumerilii, we investigated the lineage of the 4d micromere, using high-resolution long-term live imaging complemented with a live-cell cycle reporter. 4d is the origin of mesodermal lineages and the germline in many spiralians. We traced lineages at single-cell resolution within 4d and demonstrate that embryonic segmental mesoderm forms via teloblastic divisions, as in clitellate annelids. We also identified the precise cellular origins of the larval mesodermal posterior growth zone. We found that differentially-fated progeny of 4d (germline, segmental mesoderm, growth zone) display significantly different cell cycling. This work has evolutionary implications, sets up the foundation for functional studies in annelid stem cells, and presents newly established techniques for live imaging marine embryos.
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DatasetA scalable culturing system for the marine annelid Platynereis dumerilii(Public Library of Science, 2019-12-05) Kuehn, Emily ; Stockinger, Alexander W. ; Girard, Jerome ; Raible, Florian ; Ozpolat, B. DuyguPlatynereis dumerilii is a marine segmented worm (annelid) with externally fertilized embryos and it can be cultured for the full life cycle in the laboratory. The accessibility of embryos and larvae combined with the breadth of the established molecular and functional techniques has made P. dumerilii an attractive model for studying development, cell lineages, cell type evolution, reproduction, regeneration, the nervous system, and behavior. Traditionally, these worms have been kept in rooms dedicated for their culture. This allows for the regulation of temperature and light cycles, which is critical to synchronizing sexual maturation. However, regulating the conditions of a whole room has limitations, especially if experiments require being able to change culturing conditions. Here we present scalable and flexible culture methods that provide ability to control the environmental conditions, and have a multi-purpose culture space. We provide a closed setup shelving design with proper light conditions necessary for P. dumerilii to mature. We also implemented a standardized method of feeding P. dumerilii cultures with powdered spirulina which relieves the ambiguity associated with using frozen spinach, and helps standardize nutrition conditions across experiments and across different labs. By using these methods, we were able to raise mature P. dumerilii, capable of spawning and producing viable embryos for experimentation and replenishing culture populations. These methods will allow for the further accessibility of P. dumerilii as a model system, and they can be adapted for other aquatic organisms.
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ArticleThe Nereid on the rise: Platynereis as a model system(BMC, 2021-09-27) Ozpolat, B. Duygu ; Randel, Nadine ; Williams, Elizabeth A. ; Bezares-Calderón, Luis Alberto ; Andreatta, Gabriele ; Balavoine, Guillaume ; Bertucci, Paola Y. ; Ferrier, David E. K. ; Gambi, Maria Cristina ; Gazave, Eve ; Handberg-Thorsager, Mette ; Hardege, Jörg ; Hird, Cameron ; Hsieh, Yu-Wen ; Hui, Jerome ; Mutemi, Kevin Nzumbi ; Schneider, Stephan Q. ; Simakov, Oleg ; Vergara, Hernando M. ; Vervoort, Michel ; Jékely, Gáspár ; Tessmar-Raible, Kristin ; Raible, Florian ; Arendt, DetlevThe Nereid Platynereis dumerilii (Audouin and Milne Edwards (Annales des Sciences Naturelles 1:195–269, 1833) is a marine annelid that belongs to the Nereididae, a family of errant polychaete worms. The Nereid shows a pelago-benthic life cycle: as a general characteristic for the superphylum of Lophotrochozoa/Spiralia, it has spirally cleaving embryos developing into swimming trochophore larvae. The larvae then metamorphose into benthic worms living in self-spun tubes on macroalgae. Platynereis is used as a model for genetics, regeneration, reproduction biology, development, evolution, chronobiology, neurobiology, ecology, ecotoxicology, and most recently also for connectomics and single-cell genomics. Research on the Nereid started with studies on eye development and spiralian embryogenesis in the nineteenth and early twentieth centuries. Transitioning into the molecular era, Platynereis research focused on posterior growth and regeneration, neuroendocrinology, circadian and lunar cycles, fertilization, and oocyte maturation. Other work covered segmentation, photoreceptors and other sensory cells, nephridia, and population dynamics. Most recently, the unique advantages of the Nereid young worm for whole-body volume electron microscopy and single-cell sequencing became apparent, enabling the tracing of all neurons in its rope-ladder-like central nervous system, and the construction of multimodal cellular atlases. Here, we provide an overview of current topics and methodologies for P. dumerilii, with the aim of stimulating further interest into our unique model and expanding the active and vibrant Platynereis community.