Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simple nerve cells regulate swimming depth of marine plankton

19.10.2011
Ciliary beating of Platynereis gives insights into an ancestral state of nervous system evolution

As planktonic organisms the larvae of the marine annelid Platynereis swim freely in the open water. They move by activity of their cilia, thousands of tiny hair-like structures forming a band along the larval body and beating coordinately.


Light microscope image of the larva of the marine annelid Platynereis. The larvae swim freely in the sea, moved by activity of their thousands of tiny hair-like structures, which form a band along the larval body (ciliary band), beating coordinately. © Markus Conzelmann, MPI for Developmental Biology


Researchers discovered various neuropeptides in the nerve cells of Platynereis (white). They are highlighted in different colours in this image. © Albina Asadulina and Markus Conzelmann, MPI for Developmental Biology

With changing environmental conditions the larvae swim upward and downward to their appropriate water depth. Scientists of the Max Planck Institute for Developmental Biology in Tübingen, Germany have now identified some signalling substances in the larval nervous system regulating swimming depth of the larvae. These substances influence the ciliary beating and thus hold the larvae in the preferred water depth. The scientists discovered a very simple circuitry of nerve cells underlying this regulation, reflecting an early evolutionary state of the nervous system.

The locomotory system of many animals is muscle based. However, small marine animals often move by cilia. This type of locomotion is more ancient in evolution than muscle-based locomotion and very common in marine plankton. Besides the annelid larvae, the larvae of many marine invertebrates are part of this plankton, for example larvae of snails, sea shells and starfish.

“Not much is known about how the nervous systems of the marine plankton regulate ciliary beating, since the locomotion of intensely explored model organisms like the fruit fly is based on muscles,” says Gáspár Jékely. Together with his team at the Max Planck Institute for Developmental Biology and in cooperation with Thomas A. Münch at the Centre for Integrative Neuroscience in Tübingen, he has examined in detail the nervous system of marine annelid larvae of Platynereis dumerilii.

The ciliary band of Platynereis larvae serves as a swimming motor in the seawater: When cilia beat fast and continuously, larvae swim upward, and when cilia cease beating, the larvae sink. These larvae sense different environmental conditions, e.g. they react to changes in temperature, light and food supply, and alter their movement in the water column accordingly.

In order to gain insight into the regulation of this behaviour, the Tübingen scientists analysed the genes of Platynereis. They discovered several neuronal signalling substances, so-called neuropeptides in their Platynereis gene databases. Moreover, the scientists found that these neuropeptides are produced in single sensory nerve cells of the larva and are released directly at the ciliary band. The scientists concluded that these nerve cells send the sensory information directly on to the cilia. Some of these neuropeptides influence over cilia beating frequency, others act on the frequency of cilia holdups as well. By means of the neuropeptides, the scientists could control the up and down movement of freely swimming larvae and change their swimming depth in the water column deliberately.

“We have discovered that the responsible nervous circuitries are built in an unusually simple way. The sensory nerve cells have motor function at the same time, that is, they send the motion impulse directly to the ciliary band,” says Markus Conzelmann from the Max Planck Institute for Developmental Biology, first author of the study. Such simple circuitries are not known from the regulation of muscle-based locomotion. “We were astonished to find not only one neuropeptide as part of such a simple circuitry, but eleven different ones.”

According to the scientists this discovery gives insights into the form and function of nerve systems in an early stage of evolution. Moreover, the results could be interesting for other fields of marine biology: “We now have a suitable model to further explore the regulation of swimming depth in marine plankton. Since the swimming behaviour of plankton is crucial for the survival and prevalence of thousands of marine animal species, our research results could be relevant for marine ecology,” explains Gáspár Jékely. In his future research he wants to reveal how single nerve cells process the different sensory information from water pressure, temperature or salinity.

The Max Planck Institute for Developmental Biology conducts basic research in the fields of biochemistry, genetics and evolutionary biology. It employs about 325 people and is located at the Max Planck Campus in Tübingen. The Max Planck Institute for Developmental Biology is one of 80 research institutes that the Max Planck Society for the Advancement of Science maintains in Germany.

Contact
Dr. Gáspár Jékely
Max Planck Institute for Developmental Biology, Tübingen
Phone: +49 7071 601-1310
Email: gaspar.jekely@tuebingen.mpg.de
Janna Eberhardt
Max Planck Institute for Developmental Biology, Tübingen
Phone: +49 7071 601-444
Email: presse@tuebingen.mpg.de
Original publication
Markus Conzelmann, Sarah-Lena Offenburger, Albina Asadulina, Timea Keller, Thomas A. Münch and Gáspár Jékely
Neuropeptides regulate swimming depth of Platynereis larvae.
PNAS, doi: 10.1073/pnas.1109085108

Dr. Gáspár Jékely | EurekAlert!
Further information:
http://www.mpg.de/4606470/cells_regulate_swimming_depth_marine_plankton

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>