The findings, they write, may also have implications for the regulating of olfactory receptors, which are responsible for the detection of smells, because both types of receptors belong to the same protein family.
Biologists have previously found that most sensory systems follow the “one receptor molecule per receptor cell” rule. For example, photoreceptors in the fly eye and human cones—our color-sensitive photoreceptors—each express only one rhodopsin, a pigment that is sensitive to only one color. Rhodopsins are G-coupled protein receptors, a class of ancient signaling molecules that mediate not just vision, but also the sense of smell and other physiological processes.
In the PloS Biology study, the NYU researchers examined the eye of the fruit fly Drosophila. Fruit flies can be analyzed and manipulated in exquisite details by biologists and serve as a powerful model system to understand biological processes such as vision. In each of the estimated 800 individual facets that make up the fly eye, there are eight photoreceptors (R1–R8). Six of these mediate broad-spectrum detection of motion (R1–R6) and two mediate color vision (R7 and R8) and are similar to the human cone photoreceptors.
The NYU researchers, headed by Biology Professor Claude Desplan, sought to understand the mechanisms that regulate mutual exclusion of rhodopsin photoreceptor genes in the fly retina, which is poorly understood. Their results revealed a new class of photoreceptors that violates the one rhodopsin–one photoreceptor rule. This new class, located in the dorsal third of the eye, co-expresses two ultraviolet (UV)-sensitive rhodopsins (rh3 and rh4) in R7, while maintaining discrimination between green and blue rhodopsins in R8.
The NYU researchers found that this co-expression depends on a group of genes—the so-called Iroquois Complex genes—that are known to specify the dorsal side of the eye. These genes are necessary and sufficient to allow the two UV-sensitive rhodopsins to be expressed in the same R7 cell. The purpose of this co-expression of UV-sensitive pigments in a specialized part of the dorsal retina is likely to allow the flies to better orient to the sun for navigation: Flies, like bees, where this has been well documented, can discriminate between the solar side of the landscape, which has fewer radiations in the UV, and the opposite side (anti-solar), which is very UV-rich.
James Devitt | EurekAlert!
Happy hour for time-resolved crystallography
17.09.2019 | Max-Planck-Institut für Struktur und Dynamik der Materie
Too much of a good thing: overactive immune cells trigger inflammation
16.09.2019 | Universität Basel
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
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Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.
This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.
Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.
If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...
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