A whole microcosm of various bizarrely shaped life forms opens up when you look at diatoms, the primary component of ocean plankton, under a microscope.
The regularly structured silica shells of these tiny individual life forms have attracted scientists because they are particularly interesting examples of natural hybrid materials and also demonstrate unusual mechanistic and optical properties. The mechanisms of the underlying biomineralization process are not yet fully understood, but the silica shells often provide inspiration for the synthesis of man-made nanostructures.
Researchers at TU Dresden and the Max Planck Institute the Chemical Physics of Solids in Dresden have now identified another component of the diatom cell walls. As the team led by Eike Brunner reports in the journal Angewandte Chemie, they found an organic network of crosslinked chitin filaments.
Chitin is a long molecular chain of sugar building blocks, a polysaccharide. It is the second most widespread polysaccharide on Earth after cellulose. In combination with calcium carbonate (lime) and proteins, it forms the shells of insects and crabs. “Chitin plays an important role in the biomineralization of such calcium carbonate based shells and structures,” explains Brunner. “We have now been the first to demonstrate that the silica cell walls of the diatom Thalassiosira pseudonana also contain a chitin-based network.”
The researchers dissolved the silica components of diatom shells with a fluoride-containing solution. What remained behind appears under a scanning electron microscope as a delicate, net-like scaffolding. This network resembles the cell wall in form and size and consists of crosslinked fibers with an average diameter of about 25 nm. Spectroscopic examinations show that the fibers contain chitin and other, previously unknown biomolecules.
“Our results suggest that the chitin-based network structure serves as a supporting scaffold for silica deposition, while the other biomolecules actively influence it,” states Brunner. “This mechanism is thus analogous to calcium carbonate biomineralization. In addition, these networks may also mechanically stabilize the cell walls.”
Author: Eike Brunner, TU Dresden (Germany), http://analyt.chm.tu-dresden.de/
Title: Chitin-Based Organic Networks—An Integral Part of Cell Wall Biosilica in the Diatom Thalassiosira pseudonana
Angewandte Chemie International Edition, doi: 10.1002/anie.200905028
Working the switches for axon branching
26.09.2018 | Max-Planck-Institut für Biochemie
Diversity in the brain – How millions of neurons become unique
26.09.2018 | Universität Basel
Our brain is a complex network with innumerable connections between cells. Neuronal cells have long thin extensions, so-called axons, which are branched to increase the number of interactions. Researchers at the Max Planck Institute of Biochemistry (MPIB) have collaborated with researchers from Portugal and France to study cellular branching processes. They demonstrated a novel mechanism that induces branching of microtubules, an intracellular support system. The newly discovered dynamics of microtubules has a key role in neuronal development. The results were recently published in the journal Nature Cell Biology.
From the twigs of trees to railroad switches – our environment teems with rigid branched objects. These objects are so omnipresent in our lives, we barely...
The Fraunhofer FEP has been involved in developing processes and equipment for cleaning, sterilization, and surface modification for decades. The CleanHand Network for development of systems and technologies to clean surfaces, materials, and objects was established in May 2018 to bundle the expertise of many partnering organizations. As a partner in the CleanHand Network, Fraunhofer FEP will present the Network and current research topics of the Institute in the field of hygiene and cleaning at the parts2clean trade fair, October 23-25, 2018 in Stuttgart, at the booth of the Fraunhofer Cleaning Technology Alliance (Hall 5, Booth C31).
Test reports and studies on the cleanliness of European motorway rest areas, hotel beds, and outdoor pools increasingly appear in the press, especially during...
The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.
This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.
Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
21.09.2018 | Event News
03.09.2018 | Event News
27.08.2018 | Event News
26.09.2018 | Trade Fair News
26.09.2018 | Life Sciences
25.09.2018 | Health and Medicine