Researchers devise new technique and measure the forces required to unzip DNA
Fifty years after James Watson and Francis Cricks publication of the structure of DNA, research in the latest issue of the Journal of Biology shows how scientists can now measure the forces needed to tear the DNA double helix apart. The work was carried out using the first successful simultaneous combination of two important techniques for looking at single molecules - single molecule fluorescence and optical trapping.
Optical trapping, or optical tweezers, uses laser beams to counteract, and hence reveal, the tiny forces involved in the complex interactions between molecules. Single molecule fluorescence enables researchers to study biological systems on a molecule by molecule basis, by lighting up parts of the molecule in particular circumstances. The combination of the two methods applied to a single molecule has been impossible up until now because the light from the lasers used in conventional optical traps is too bright to allow single molecule florescence to be seen.
Matthew Lang, Polly Fordyce and Steven Block devised a new method, which uses special filters and specific fluorescence labels, to successfully combine the techniques of optical trapping and single-molecule fluorescence for the first time. They used this new method to simultaneously examine the structural and mechanical changes occurring as a small fragment of DNA was ripped apart.
Gordon Fletcher | BioMed Central Limited
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Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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