Scientists have discovered that the heart of a carp keeps beating when it is starved of oxygen for five days. “This is the first time that a vertebrate heart has been shown to survive such prolonged periods without oxygen and actually keep beating at the same rate as when oxygen is available” says Jonathan Stecyk (Simon Fraser University), presenting his latest results at the annual SEB meeting in Edinburgh this week.
“If I were to take oxygen away from your heart it would die in two minutes” says Mr. Stecyk. “But the heart of a carp survives and keeps beating as normal for five days without oxygen.” Crucian carp live in shallow ponds in Scandinavia, which are sealed off by ice in winter. Animals have two problems in such low oxygen environments: they cannot produce enough energy, and have to cope with the build-up of lactic acid that is produced by anaerobic respiration.
“There are two possible coping strategies in low oxygen conditions” says Mr. Stecyk “Either the animal lowers its demand for energy, or it increases the rate of processes that deliver energy.” Carp rely on the second method, which requires a large supply of fuel. Luckily carp have the largest livers among vertebrates, with the largest energy stores relative to body size. By having a heart that goes on, the fish can move this fuel around the body. They can also shuttle lactic acid to the muscles, the only tissue that can convert lactic acid to ethanol, which is then transferred to the gills where it can be excreted. Maintaining circulation allows the fish to avoid the build-up of waste products which could eventually poison the animal. In the face of their hostile environments, carp have developed a complex survival strategy relying on the unique ability of their hearts to survive without oxygen.
Yfke van Bergen | alfa
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22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
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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