A team of researchers has discovered a molecular missing link that helps explain why fasting brings on acute attacks of the genetic disease hepatic porphyria, according to a new report in the 26 August issue of the journal Cell. The finding could help improve treatments for those suffering from the disease, which may have been the culprit behind the "madness" of King George III of England.
Porphyria disease is caused by defects in the enzyme pathway that produces heme, a critical iron compound found throughout the body, most notably in red blood cells. The defects lead to the overproduction and toxic accumulation of the intermediate molecules that eventually become heme. Researchers and physicians have long known that fasting can cause acute attacks of the disease, and that the attacks can be relieved with glucose or other high-carbohydrate treatments, but the exact link between fasting and the attacks has been mysterious until now.
In the Cell study, Bruce Spiegelman of the Dana-Farber Cancer Institute and Harvard Medical School and colleagues show that fasting increases levels of a metabolic protein called PGC-1a. The "starvation" signal that fasting sends throughout the body prompts PGC-1a to jump-start the process of creating glucose from scratch in the liver. However, PGC-1a also regulates the activity of an enzyme called ALAS-1, the first key enzyme in the heme production pathway.
Heidi Hardman | EurekAlert!
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Party discipline for jumping genes
22.09.2017 | Veterinärmedizinische Universität Wien
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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22.09.2017 | Physics and Astronomy