Research into plant cells is far from complete. Scientists under the biochemist Professor Peter Dörmann at Universität Bonn have now succeeded in describing the function of chloroplasts in more detail. These are plant and algal cell structures that are responsible for photosynthesis. The results have now been published in the scientific journal "Proceedings of the National Academy of Sciences of the USA" (PNAS).
The study makes reference to the endosymbiotic theory, which was put forward back in 1883 by the Bonn university scholar Andreas Franz Wilhelm Schimper and has long been viewed as proven.
According to the theory, at least a billion years ago, a photosynthetic bacterium must have penetrated a plant host cell, where it developed into a chloroplast. Without this so-called "endosymbiosis", photosynthesis, which is the process by which light energy converts carbon dioxide and water into sugar and oxygen, would not be possible in plants.
This former bacterium inside the host cell is surrounded by two membranes. The predominant components of these membranes are the so-called galactolipids. These two envelope membranes were the focus of attention of the scientists during their years of investigation.
"The question that our research sought to answer was exactly what each membrane is responsible for", explains Professor Peter Dörmann, Director of the Institute of Molecular Physiology and Biotechnology of Plants at Universität Bonn.
Scientists experiment with plant mutants
For this purpose, the scientists experimented with mutants of the often-used research plant thale cress (Arabidopsis thaliana). They modified the mutant plant by adding various genetically manipulated variants of a protein of the galactolipid production system, which is located on the outer membrane of the chloroplast. The most important finding: This protein is essential for the embedding of the former bacterium in the cell.
"Without the protein, the chloroplast cannot survive. Without the chloroplast, the plant cannot survive", says Barbara Kalisch, doctoral researcher at Universität Bonn, who was one of the lead authors for the now published article.
"Lipids cannot simply move through water"
In addition to the production of the galactolipids, the protein is also involved in the transfer of galactolipids from the outer to the inner of the two envelope membranes. In their experiments, the researchers also placed the protein artificially on the inner membrane. Lipid production worked there, too; the plant remained able to survive. When the protein is on the inner envelope membrane, no further transport is necessary. Why the location in nature is on the outside and not the inside, has not yet been clarified.
The experiments also indicate that the protein is the reason that there can be any lipid exchange at all between the two envelope membranes of the chloroplasts. That is important, so that the chloroplast, and with it the plant, can grow. The space between the two envelope membranes is filled with water, but "lipids cannot simply move through water", explains Prof. Peter Dörmann of Universität Bonn. However, other factors can affect this lipid exchange. "Our investigations to date certainly do not represent the end of our research", says Dörmann.
Publication: Amélie A. Kelly, Barbara Kalisch, Georg Hölzl, Sandra Schulze, Juliane Thiele, Michael Melzer, Rebecca L. Roston, Christoph Benning, and Peter Dörmann: Synthesis and transfer of galactolipids in the chloroplast envelope membranes of Arabidopsis thaliana, "Proceedings of the National Academy of Sciences of the USA", DOI: 10.1073/pnas.1609184113
Contact for the media:
Prof. Peter Dörmann
Institute of Molecular Physiology and
Biotechnology of Plants
Tel.: +49-228 73-2830
Johannes Seiler | idw - Informationsdienst Wissenschaft
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
Scientists generate an atlas of the human genome using stem cells
24.04.2018 | The Hebrew University of Jerusalem
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Life Sciences
24.04.2018 | Materials Sciences
24.04.2018 | Trade Fair News