Dr. Mario Capecchi and colleagues at the University of Utah and the Department of Veterans Affairs Medical Center (Salt Lake City, UT) have discovered that a gene called xanthine oxidoreductase, or XOR for short, is required for lactation in female mice. This previously unidentified role for XOR in lactation reveals a possible genetic basis for the lactation difficulties experienced by nearly 5% of women.
XOR was originally identified as encoding an enzyme involved in purine catabolism (the breakdown of adenine and guanine nucleotide bases). Because XOR is expressed in nearly all cells of the body and its protein product participates in a basic metabolic process fundamental to cell survival, XOR was labeled as a "housekeeping gene." But in addition to its constitutive expression patterns, XOR is also highly expressed in lactating mammary epithelium beginning in late pregnancy – prompting researchers to suspect an additional, and perhaps different, role for XOR in the lactating mammary gland.
To identify the function of XOR in the lactating mammary gland, Dr. Capecchi and colleagues generated mice lacking either one (heterozygous) or both (homozygous) functional copies of the XOR gene. As expected for homozygous mutants of a housekeeping gene, homozygous XOR-mutant mice died by 6 weeks of age. In contrast, though, the heterozygous XOR-mutant mice appeared normal, healthy and fertile, but first author Claudia Vorbach and colleagues soon noticed that pups from the XOR heterozygous females all died ~12 days postpartum. The researchers found that pups born to heterozygous XOR-mutant female mice – regardless of the pups XOR status – were essentially starving due to their mothers inability to maintain lactation.
Heather Cosel | EurekAlert!
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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...
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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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