The researchers started the effort for creation of somatic transgenic animals several years ago (InformNauka described these investigations in the material entitled “Transgenic Cows and Pigs” in 2002). Since then, they have obtained transgenic goats and specified influence of various factors on protein produce.
Utilization of transgenic agricultural animals as fermenters bodes well for pharmaceutical industry. However, the traditional method of getting them (when the DNA is introduced directly into the impregnated ovule) is inefficient. Only 1 percent of transplanted embryos turn out to be transgenic, and only 60 percent of transgenic animals provide at lease some amount of the required protein. Moreover, it would be clear who will give protein and how much of it several years after the DNA introduction when the transgenic ovule would turn into an animal of a proper age. Fortunately, there is a less lengthy and expensive way of gene transfer – the required gene is introduced directly into the mammary gland of a cow, goat or a sow.
Of course, the method is rather troublesome. First, the required gene should be built into the retrovirus’ genome, and the viral DNA should be introduced into the cell culture. Retroviruses possess a property very precious to genetic engineering – to survive in the cell, they must necessarily build their DNA into the cell’s chromosome.
The cells are reproducing and along with that they are producing new viral particles, and when they are introduced into the mammary gland, the viral particles penetrate the gland’s cells and build their DNA in the cellular genome. Thus, the mammary gland’s cells get the required gene and start producing the useful protein together with milk.
The researchers dealt with genes of two proteins participating in maturation of blood cells: erythropoietin and granulocyte-colony-stimulating factor. The maximum concentrations of these proteins in milk reached about 1,000 and 200 nanogram per milliliter, respectively. However, contemporary technologies allow to educe proteins from milk at ten times lower concentrations (only 25 nanogram per milliliter).
Practically all laboratory animals synthesized the required proteins during the entire period of lactation. However, the quantity of protein in milk changes from day to day. The first third of lactation is more productive than the two following ones. The researchers have determined that the highest possible production of proteins requires that gene constructions should be introduced into the mammary gland of cows in the 4th –6th month of pregnancy, that of goats – in the 4th –5th month of pregnancy, and that of sows – during the last trimester of pregnancy. The maximum production of proteins was achieved with cows, but the average concentration of proteins turned out to be higher in the milk of goats and sows.
In the researchers’ opinion, they have developed a technology, which allows to get the highest quantity of industrially important protein from the milk of an animal as compared to other existing gene transfer methods. Although transgenic animals, obtained by this method, do not transmit the new gene to descendants, they efficiently produce biologically active proteins in required quantities.
Nadezda Markina | alfa
Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen
Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
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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