Neurobiologists from the University of Zurich have discovered that this camouflage mechanism actually started out as sunscreen to protect the fish against DNA damaging shortwave solar radiation at embryonic stages.
Zebrafish with different pigmentation and camouflage. The bottom animal is on a light subsurface. The top animal is blind, thus incapable of discerning the lightness of the subsurface and
Picture: Stephan Neuhauss / UZH
Camouflage among zebrafish larvae. The left-hand larva is exposed to bright light and has little pigmentation; the right-hand larva against a dark subsurface is more heavily pigmented.
Picture: Stephan Neuhauss / UZH
For diurnal animals like zebrafish embryos, which grow up in shallow pools and are practically see-through, exposure to the sun constitutes a major problem since ultraviolet (UV) radiation damages DNA.
Neurobiologists Stephan Neuhauss and Kaspar Müller from the Institute of Molecular Biology at the University of Zurich set about investigating which mechanisms zebrafish embryos use to protect themselves against the aggressive UV radiation. Interestingly, the two scientists reveal in their article recently published in the journal PLOS ONE, the UV-protection mechanism also doubles as camouflage.
Sunscreen already from day two
For their study, the scientists examined zebrafish embryos, the skin cells of which already possess pigments known as melanosomes from the second day after fertilization – even before their eyes have developed. “In strong solar radiation, the pigments spread along predetermined paths within the cells, after which the zebrafish embryo appears darker,” explains Neuhauss. As the researchers discovered, this distribution process of dark pigments in the presence of intense light always takes place, regardless of whether the embryo is on a light or dark subsurface. Surprisingly, the embryos display a noticeable change from the third day after fertilization: They adapt to the subsurface. According to Neuhauss, this is because the embryos can see from day three and have eyes with UV-sensitive photoreceptors in the retina. From this moment on, they are able to discern whether they are on a light or dark subsurface and can adapt and thus camouflage themselves accordingly. As long as the animal is in the embryonic stage and see-through, however, the benefits of UV protection prevail.When the skin is no longer transparent and does not require protection against aggressive radiation, the selective distribution of the pigments within the skin cells is predominantly used for camouflage purposes. And with good reason: Being able to adapt to a lighter or darker subsurface and camouflage yourself reduces the chance of being spotted and eaten. “The original UV protection turns into a camouflage mechanism – a striking example of the secondary use of an existing capability,” Neuhauss concludes.
Kaspar P. Müller, Stephan C. F. Neuhauss, Sunscreen for Fish: Co-option of UV light protection for camouflage. PLOS ONE. January 29, 2014. Link: http://dx.plos.org/10.1371/journal.pone.0087372
Bettina Jakob | Universität Zürich
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy