Der hormonale einfluss des Gehirns auf die sexuelle Entwicklung bei dem polychaeten Platynereis dumerilii

1966 ◽  
Vol 6 (1) ◽  
pp. 26-73 ◽  
Author(s):  
Carl Hauenschild
JOM ◽  
2021 ◽  
Author(s):  
Luis Zelaya-Lainez ◽  
Giuseppe Balduzzi ◽  
Olaf Lahayne ◽  
Kyojiro N. Ikeda ◽  
Florian Raible ◽  
...  

AbstractNanoindentation, laser ablation inductively coupled plasma mass spectroscopy and weighing ion-spiked organic matrix standards revealed structure-property relations in the microscopic jaw structures of a cosmopolitan bristle worm, Platynereis dumerilii. Hardness and elasticity values in the jaws’ tip region, exceeding those in the center region, can be traced back to more metal and halogen ions built into the structural protein matrix. Still, structure size appears as an even more relevant factor governing the hardness values measured on bristle worm jaws across the genera Platynereis, Glycera and Nereis. The square of the hardness scales with the inverse of the indentation depth, indicating a Nix-Gao size effect as known for crystalline metals. The limit hardness for the indentation depth going to infinity, amounting to 0.53 GPa, appears to be an invariant material property of the ion-spiked structural proteins likely used by all types of bristle worms. Such a metal-like biogenic material is a major source of bio-inspiration.


PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e96702 ◽  
Author(s):  
Kathrin Pfeifer ◽  
Christoph Schaub ◽  
Katrin Domsch ◽  
Adriaan Dorresteijn ◽  
Georg Wolfstetter

2017 ◽  
Author(s):  
Csaba Verasztó ◽  
Nobuo Ueda ◽  
Luis A. Bezares-Calderón ◽  
Aurora Panzera ◽  
Elizabeth A. Williams ◽  
...  

AbstractCiliated surfaces harbouring synchronously beating cilia can generate fluid flow or drive locomotion. In ciliary swimmers, ciliary beating, arrests, and changes in beat frequency are often coordinated across extended or discontinuous surfaces. To understand how such coordination is achieved, we studied the ciliated larvae of Platynereis dumerilii, a marine annelid. Platynereis larvae have segmental multiciliated cells that regularly display spontaneous coordinated ciliary arrests. We used whole-body connectomics, activity imaging, transgenesis, and neuron ablation to characterize the ciliomotor circuitry. We identified cholinergic, serotonergic, and catecholaminergic ciliomotor neurons. The synchronous rhythmic activation of cholinergic cells drives the coordinated arrests of all cilia. The serotonergic cells are active when cilia are beating. Serotonin inhibits the cholinergic rhythm, and increases ciliary beat frequency. Based on their connectivity and alternating activity, the catecholaminergic cells may generate the rhythm. The ciliomotor circuitry thus constitutes a stop-and-go pacemaker system for the whole-body coordination of ciliary locomotion.


2019 ◽  
Author(s):  
Emily Kuehn ◽  
Alexander W. Stockinger ◽  
Jerome Girard ◽  
Florian Raible ◽  
B. Duygu Özpolat

ABSTRACTPlatynereis 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 present 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.


2013 ◽  
pp. 93-113
Author(s):  
J. Krieg ◽  
I.-T. Bäckert-Sifeddine ◽  
L. Kiesel
Keyword(s):  

2020 ◽  
Author(s):  
Jyothi Kara ◽  
Cinthya S. G. Santos ◽  
Angus H. H. Macdonald ◽  
Carol A. Simon

The perceived cosmopolitanism of polychaete worms could be an artefact of historical factors such as poor original species descriptions, lack of type material and the European taxonomic bias, to name a few. Thus, it is possible that several cosmopolitan species hide complexes of cryptic and pseudocryptic species. Two putative cosmopolitan species, Platynereis dumerilii and Platynereis australis, collected in South Africa were investigated here (1) to determine whether the South African taxa are conspecific with the morphologically identical taxa from France and New Zealand (the respective type localities of P. dumerilii and P. australis), (2) to compare the South African species morphometrically to determine whether their morphological characters are reliable enough to separate them, and (3) to investigate whether these species have geographically structured populations along the coast of South Africa. Molecular data (COI and ITS1) confirm that P. dumerilii and P. australis do not occur in South Africa. Instead, the South African taxon formerly thought to be Platynereis dumerilii is new and is described here as Platynereis entshonae, sp. nov.; the identity of the other South African species is currently unresolved and is treated here as Platynereis sp. Surprisingly, Platynereis massiliensis (type locality: Marseilles) nested within the South African Platynereissp. clade but, since it is part of a cryptic species complex in the Mediterranean, the name is considered doubtful. Morphological characters traditionally used to define these South African Platynereis species are not reliable as predefined morphological groupings do not match phylogenetic clades and principal component scores revealed no separation in morphological characters that could distinguish between them. Haplotype networks and phylogenetic trees revealed that P. entshonae, sp. nov. and Platynereis sp. have geographically structured populations along the South African coast. http://zoobank.org/urn:lsid:zoobank.org:pub:6E36A210-9E48-430F-8A93-EDC27F0C5631


1999 ◽  
Vol 54 (12) ◽  
pp. 1145-1174 ◽  
Author(s):  
Ingo Röhl ◽  
Bernd Schneider ◽  
Bettina Schmidt ◽  
Erich Zeeck

Sex pheromones, released with the coelomic fluid by male Platynereis dumerilii initiate egg release in swarming females. The egg release pheromone, isolated from the coelomic fluid of sexually mature males, was identified as ʟ-Ovothiol A, which was found in male marine invertebrates for the first time. Isolation was obtained by reversed-phase high-performance liquid chromatography in the biologically inactive disulfide form.


1990 ◽  
Vol 31 (39) ◽  
pp. 5613-5614 ◽  
Author(s):  
E. Zeeck ◽  
J.D. Hardege ◽  
H. Bartels-Hardege ◽  
G. Wesselmann

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