Founded in 1755, the university was renamed in honor of its founder, Mikhail Lomonosov, in 1940. It also claims to have the tallest educational building in the world. Its current rector is Viktor Sadovnichiy.
A few more narrowly specialized Moscow colleges, including the Moscow Institute of Physics and Technology and the Moscow State Institute of International Relations were split off from MSU at one time or another and have since established strong reputations of their own, arguably even surpassing their parent in terms of prestige and quality of education.
The university has well-established contacts with the most distinguished universities in the world, exchanging students and lecturers with the leading international institutions of higher education. It houses the UNESCO International Demography Courses, the UNESCO Hydrology Courses, the International Biotechnology Center, the International LASER Center, courses or seminars on Russian as a foreign language. In 1991 the French University College, the Russian-American University and the Institute of German Science and Culture were opened.
The university has awarded honorary degrees to more than 60 scientists, statesmen and politicians from abroad. Many prominent university scholars and scientists in return hold honorary degrees from foreign academies and universities.
Lomonosov Moscow State University research articles from Innovation Toronto
The eye’s lacrimal gland is small but mighty. This gland produces moisture needed to heal eye injuries and clear out harmful dust, bacteria and other invaders.
If the lacrimal gland is injured or damaged by aging, pollution or even certain pharmaceutical drugs, a person can experience a debilitating condition called aqueous deficiency dry eye (ADDE)—sometimes called “painful blindness.”
Now a new study in animal models, led by scientists at The Scripps Research Institute (TSRI), suggests that lacrimal glands can be repaired by injecting a kind of regenerative “progenitor” cell.
“This is the first step in developing future therapies for the lacrimal gland,” said TSRI biologist Helen Makarenkova, who led the study.
The findings were published this week in the online Early Edition of the journal Stem Cells Translational Medicine.
Up for the Challenge
If injured, a healthy lacrimal gland naturally regenerates itself in about seven days. When diseased and chronically inflamed, however, regeneration stops—and scientists are not sure why.
In the new study, Makarenkova and her colleagues looked at whether they could kick start regeneration by injecting progenitor cells into the lobes that make up the lacrimal gland. Progenitor cells are similar to stem cells in their ability to differentiate into different kinds of tissue. In this study, the researchers used progenitor cells that were poised to become epithelial tissue, a key component of the lacrimal gland.
The researchers knew they faced a major challenge: sorting and separating “sticky” epithelial cell progenitors without destroying them.
“We had to figure out how to dissociate the tissue into single cells without completely obliterating everything,” said Anastasia Gromova, the study’s first author, now a graduate student at the University of California, San Diego, who spearheaded the project while interning at TSRI during her undergraduate years.
The researchers solved this problem by developing markers to label the cells of interest and then testing different enzymes and other reagents to draw them out of tissues.
Restoring Eye Health
With these cells in hand, the researchers injected them into the lacrimal glands of mouse models of Sjogren’s syndrome, an autoimmune disease that results in ADDE, dry mouth and other symptoms. The team used only older, female mice because ADDE most commonly strikes that demographic in humans.
The treated mice showed a significant increase in tear production, indicating—for the first time—that epithelial cell progenitors could repair the lacrimal gland. Further tests suggested that epithelial cell progenitors helped by restoring the connection between cells called myoepithelial contractile cells and the lacrimal gland’s secretory cells, which produce tears.
The next step in this research will be to study how long the improvement in the lacrimal gland lasts after progenitor cell injections. Makarenkova said the eventual goal is to develop therapies to boost a patient’s own regenerative abilities.
In addition to Makarenkova and Gromova, authors of the study, “Lacrimal Gland Repair Using Progenitor Cells,” were Dmitry A. Voronov of TSRI, the Russian Academy of Sciences and the A.N. Belozersky Institute of Physico-Chemical Biology of the Lomonosov Moscow State University; Miya Yoshida and Suharika Thotakura of TSRI; Robyn Meech of Flinders University; and Darlene A. Dartt of the Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School.
Physicists of Moscow State University have created a magnetic field which helps avoid implants rejection
A group of Russian physicists, with the contribution from their Swiss colleagues, developed a way to use the therapeutic effect of heating or cooling the tissues due to the magnetocaloric effect. The article with the results of the work was published in the latest issue of the International Journal of Refrigeration.
A team of the Lomonosov Moscow State University scientists proposed a new way to use the magnetocaloric effect for the targeted delivery of drugs to the implants. Vladimir Zverev, one of the authors (Lomonosov Moscow State University, Faculty of Physics) claims that this is a unique method that uses a negative magnetocaloric effect.
The gist of the magnetocaloric effect (MCE) is reduced to the fact that when exposed to an external magnetic field, the magnetic material changes its temperature, sometimes rising and sometimes, on the contrary, falling (depending on the material). This significant physical phenomenon was discovered in the nineteenth century, although the effect has been described only in 1917. Over the past century, the MCE has been minutely studied, but the interest of researchers increased dramatically in recent decades. This is due to, first, a significant contribution to the physics of magnetic materials, and, second, a fairly extensive area of its possible applications. It can be very successfully used in low-temperature physics, for the production of heat engines, refrigeration and so on.
However, the majority of these applications is not ready for commercial use yet, mainly due to the unavailability of the technology. Speaking, for example, about domestic magnetic refrigerators, although they are being developed today by many scientific and industrial laboratories around the world, according to Vladimir Zverev, a member of the Physics Department of MSU, such refrigerators, if they were made today, would be very expensive.
‘For such a refrigerator magnetic field of around one Tesla is required, which at today’s possibilities makes the prices very high and therefore commercially unacceptable – the very device to generate such a field will cost at least fifteen hundred dollars. It remains to wait for them to fall in price’, Vladimir Zverev says.
However, this did not prevent the authors from suggesting a new application of the magnetocaloric effect, almost ready for massive use – this time in medicine.
One of the developed methods is called “magnetic fluid hypothermia” and consists in heating cancer tumors with special magnetic nanoparticles, delivered directly to the tumor site. To do this, the researchers developed and created a unique tool to create an alternating high-frequency magnetic field with no analogues in the world, as Vladimir Zverev says. Today, with the help of this facility in the Blokhin Scientific Cancer Centre, the primary research of various cancerous cell cultures was conducted. The studies on mice were also carried out, which proved biocompatibility and non-toxicity of the microparticles. The experiments on the microparticles’ pharmacokinetics are conducted as well, which demonstrate its ability of retention in the tumor, spreading in the body with the blood flow etc.
If the possibility of using such magnetocaloric effect in the scientific literature is at least mentioned – in fact that the heating of the tumor may lead to its degradation has long been known, – the second method, proposed by the scientists, is quite unique.
It is known that one of the problems when implanted of foreign parts in human- artificial joints, abdominal nets, stents esophagus, urinary and biliary ducts, etc. – is the likelihood of rejection. The authors offer to apply a special coating to implants (yet at the stage of the preparation for installing), consisting of several layers. The first layer is a magnetic material, which is cooled in an external magnetic field (a material with a negative magnetocaloric effect). This layer may be a thin film or a suspension of magnetic microparticles. The second layer is the polymer matrix, in which, as a sponge, absorbs the drug. The polymer matrix is in direct thermal contact with the magnetocaloric material. This entire structure is placed in the body during the operation.
The fact that the polymer used in the technology at the normal body temperature, i.e. at a temperature above 37 degrees, behaves like a jelly, which holds the drug inside. When the magnetic field lowers the temperature, the polymer transits in a liquid state and releases drug at the site of theimplantation. For example, when, after insertion of the implant an inflammation occurs, the non-invasive application of an external magnetic field (for example, in MRI) allows to release the desired dose of drug over the desired time and place.
This method of the ‘targeted’ drug delivery is good, in particular, by the fact that it only affects the source of inflammation and remains the rest of the body uninfluenced, that is, by definition, completely harmless. There is a problem though – it is unclear what to do if the coated drug is over.
Zverev says that this problem is solvable: ‘First, in some cases just a single drug input is need, for example, to paste the abdominal mesh. A release dosage portions of the drug can be controlled by regulating the magnitude of the external magnetic field. It is also possible to replenish a the coat, using the fact that a drug may be chemically linked to the magnetic particles which can be ‘dragded’ to the desired location in the body by an external magnetic field. This method we haven’t developed however, and it is only ideas yet’.
Scientists from the Moscow State University together with colleagues from Germany have found that a derivative of -radialene, a molecule known to the science for nearly 30 years, can be used to create organic semiconductors. Its purpose is the development of electronic devices based on organic materials.
Russian scientists suggest a PC to solve complex problems tens of times faster than with massive supercomputers
A group of physicists in Russia has learned to use a personal computer for calculations of complex equations of quantum mechanics, usually solved with help of supercomputers. This PC does the job much faster.
A group of physicists from the Skobeltsyn Institute of Nuclear Physics, the Lomonosov Moscow State University, has learned to use a personal computer for calculations of complex equations of quantum mechanics, usually solved with help of supercomputers. This PC does the job much faster. An article about the results of the work has been published in the journal Computer Physics Communications.
Senior researchers Vladimir Pomerantcev and Olga Rubtsova, working under the guidance of Professor Vladimir Kukulin (SINP MSU), were able to use on an ordinary desktop PC with GPU to solve complicated integral equations of quantum mechanics — previously solved only with the powerful, expensive supercomputers. According to Vladimir Kukulin, the personal computer does the job much faster: in 15 minutes it is doing the work requiring normally 2-3 days of the supercomputer time.
The equations in question were formulated in the ’60s by the Russian mathematician Ludwig Faddeev. The equations describe the scattering of a few quantum particles, i.e., represent a quantum mechanical analog of the Newtonian theory of the three body systems. As the result, the whole field of quantum mechanics called “physics of few-body systems” appeared soon after this.
An international team of including the Lomonosov Moscow State University researchers discovered which enzyme enables Escherichia coli bacterium (E. coli) to breathe. The study is published in the Scientific Reports.
There is a prospect of a new type of antibiotics “turning off” the oxygen only to the harmful bacteria cells, not to human cells.
Scientists discovered how the E. coli bacterium can survive in the human gut – earlier the question how they breathe was a mystery to experts. Vitaliy Borisov, Senior Researcher, Doctor of Biological Sciences, Professor of the Russian Academy of Sciences, A.N. Belozersky Research Institute physical and chemical biology employee, the Lomonosov Moscow State University and one of the authors, explains that breathing E. coli uses special enzymes, which are absent in the human body. This means that the discovery of the scientists can contribute to the creation of new drugs, which will be detrimental to the bacteria without harming a human.
The energy for the vital activity of any organism comes from food, and is generated by the means of redox processes in the body. The food is converted into energy not directly but through intermediaries. First, the complex molecules are decomposed into simpler: proteins are decomposed into amino acids, fats – to fatty acids, carbohydrates – to monosaccharides. Oxidation of simpler molecules releases energy, which all is contained in the electrons.
The electrons passes to the respiratory chain with the so-called reducing equivalents (electron-carrying compound). They are NADH (nicotinamide adenine dinucleotide) and ubiquinol, also known as coenzyme Q. These two basic reducing equivalents fully cope with the processing of food: NADH is a water-soluble compound and ubiquinol is fat-soluble. Membranous enzymes accept electrons from reducing equivalents and transfer them to molecular oxygen.
The terminal cytochrome oxidase is the main membrane enzyme responsible for the human mitochondrial respiration and was thought to be used for the breath of E. coli as well. The scheme of oxidases action is simple: transferring electrons to molecular oxygen, reducing equivalents are oxidized again, and as a result “the energy currency” of the cell – the proton-moving force is generated.
‘If you stop breathing, you die just because oxygen does not flow to the oxidase, and it does not produce energy,’ said Vitaly Borisov.
The Escherichia coli bacterium lives in the gastrointestinal tract, where a lot of hydrogen sulfide is produced, which attenuates mitochondrial respiration. Free hydrogen sulfide inhibits cytochrome oxidase work. Its concentration exceeds several hundred times the minimum concentration required for substantial blocking of this enzyme. Hence, it seems that the E. coli bacterium cannot “breathe”, but despite that the bacteria somehow survive in the intestine. The researchers assumed that the breath in the presence of hydrogen sulfide is still possible, but due to other oxidase. The fact is that the breath in people and bacteria occur in different ways. Each cell in our body “breathes” due to the work of only the cytochrome-c oxidase, others we have not. However, the E. coli bacteria has two types of oxidase: bo-type cytochrome oxidase (analogue of “human” cytochrome-c oxidase) and completely different bd-type cytochromes.
‘Our hypothesis was that the bd-type oxidase (bd-I and bd-II) are more resistant to the hydrogen sulfide inhibition than the bo-type cytochrome oxidase,’ commented Vitaly Borisov.
To test this hypothesis scientists needed to learn how the sulfide presence in the environment affects the growth of the E. coli bacteria cells, which have only one terminal oxidase (bd-I, bd-II or bo) in the respiratory chain. a variety of biochemical, biophysical and microbiological methods and approaches were applied, as well as the method of the intended mutagenesis.
The hypothesis was fully confirmed.
‘Bo-oxidase’s activity is completely inhibited by the hydrogen sulfide, while the work of the bd-oxidases remains untouched by the H2S. Thus, in order to successfully produce the main types of “the energy currency” under a high concentration of hydrogen sulfide, the intestinal microflora inhabitants should use a unique type of terminal oxidases, which is missing in the cells of humans and animals,’ said Vitaly Borisov.
The discovery could be used in the future to develop medicines that regulate the intestinal microflora and relieving it from harmful bacteria. As human cells do not contain the bd-type oxidase, the question of the ability to combat disease-causing bacteria without causing harm to the human body becomes relevant. For example, the bacterium causing tuberculosis, which’s primarily membrane enzyme is also a bd-type oxidase, quickly gaining resistance to classical antibiotics. Through this study there is a prospect of a new type of antibiotics “turning off” the oxygen only to the harmful bacteria cells, not to human cells.
The Lomonosov Moscow State University scientists developed a growth technology of single crystals for creating a unique eye-safe laser
A team of the Lomonosov Moscow State University scientists and the Belarusian National Technical University has created a unique laser, which is a compact light source with wavelengths harmless to the human eye. The development can be used in medicine, communications systems and also in research. The works are published in Journal of Crystal Growth and Optics Letters.
‘In collaboration with our colleagues of the Center for Optical Materials and Technologies, Belarusian National Technical University, we have developed a highly efficientdiode-pumped eye-safe laser, which can be used in ophthalmology, communication systems and ranging’, says Nikolay Leonyuk, Professor, Department of Crystallography and Crystal Chemistry, Geological Faculty, the Lomonosov Moscow State University. The development of such laser became possible to the fact that the team of scientists had created a laboratory growth technology of single crystals with desired properties.
The emission with wavelengths of 1500 — 1600 nm is agreeably safe for the eyes and seems prospective for practical applications in medicine, ranging (determining the distance from the observer to the object), communication systems andoptical location. This feature is explained with, first, the fact that the light-refracting system of the eye (cornea and crystalline lens) have a sufficiently high absorption coefficient in this part of the spectrum, so only a small fraction of the energy reaches the sensitive retina. Second, the radiation in the 1500 — 1600 nm spectral range suffers low losses passing through the atmosphere, and it makes advantages for their applications in telecoms.
Learn more: A laser for your eyes
Russian scientists develop a control system for rapid superconducting memory cells
A group of scientists from Moscow Institute of Physics and Technology and from the Moscow State University has developed a fundamentally new type of memory cell based on superconductors – this type of memory will be able to work hundreds of times faster than the types of memory devices commonly used today, according to an article published in the journal Applied Physics Letters.
“With the operational function that we have proposed in these memory cells, there will be no need for time-consuming magnetization and demagnetization processes. This means that read and write operations will take only a few hundred picoseconds, depending on the materials and the geometry of the particular system, while conventional methods take hundreds or thousands of times longer than this,” said the corresponding author of the study, Alexander Golubov, the Head of MIPT’s Laboratory of Quantum Topological Phenomena in Superconducting Systems.
Golubov and his colleagues have proposed creating basic memory cells based on quantum effects in “sandwiches” of a superconductor – dielectric (or other insulating material) – superconductor, which were predicted in the 1960s by the British physicist Brian Josephson. The electrons in these “sandwiches” (they are called “Josephson junctions”) are able to tunnel from one layer of a superconductor to another, passing through the dielectric like balls passing through a perforated wall.
Today, Josephson junctions are used both in quantum devices and conventional devices. For example, superconducting qubits are used to build the D-wave quantum system, which is capable of finding the minima of complex functions using the quantum annealing algorithm. There are also ultra-fast analogue-to-digital converters, devices to detect consecutive events, and other systems that do not require fast access to large amounts of memory. There have also been attempts to use the Josephson Effect to create ordinary processors. An experimental processor of this type was created in Japan in the late 1980s. In 2014, the research agency IAPRA resumed its attempts to create a prototype of a superconducting computer.
Josephson junctions with ferromagnets used as the middle of the “sandwich” are currently of greatest practical interest. In memory elements that are based on ferromagnets the information is encoded in the direction of the magnetic field vector in the ferromagnet. However, there are two fundamental flaws with this process: firstly, the low density of the “packaging” of the memory elements – additional chains need to be added to provide extra charge for the cells when reading or writing data, and secondly the magnetization vector cannot be changed quickly, which limits the writing speed.
The group of physicists from MIPT and MSU proposed encoding the data in Josephson cells in the value of the superconducting current. By studying the superconductor-normal metal/ferromagnet-superconductor-insulator-superconductor junctions, the scientists discovered that in certain longitudinal and transverse dimensions the layers of the system may have two energy minima, meaning they are in one of two different states. These two minima can be used to record data – zeros and ones.
In order to switch the system from “zero” to “one” and back again, the scientists have suggested using injection currents flowing through one of the layers of the superconductor. They propose to read the status using the current that flows through the whole structure. These operations can be performed hundreds of times faster than measuring the magnetization or magnetization reversal of a ferromagnet.
“In addition, our method requires only one ferromagnetic layer, which means that it can be adapted to so-called single flux quantum logic circuits, and this means that there will be no need to create an entirely new architecture for a processor. A computer based on single flux quantum logic can have a clock speed of hundreds of gigahertz, and its power consumption will be dozens of times lower,” said Golubov.
MSU chemists created a material able to enhance a charge rate of li-ion batteries drastically
Nowadays Li-ion batteries power a wide range of electronic devices: mobile phones, tablets, laptops. They became popular in 90s and subsequently ousted widespread nickel-metal hydride batteries.
However, Li-ion batteries suffer a number of disadvantages. For example, their capacity may drop when temperature falls below zero. The price is also discomforting, which is mostly caused by use of expensive lithium-containing materials. For instance, Li-ion batteries make about half a price of a popular electro car Tesla Model S. On the other hand, Li-ion batteries are compact, easy to use and highly capacious, which means that your device would live long having a relatively small battery.
A key element of the Li-ion batteries limiting its capacity is a material used for its cathode. For the majority of the materials their capacity limit has already been reached. Hence, scientists and engineers are actively searching for new cathode materials capable of recharging completely within minutes, operate under high current densities, and store more energy.
One of the most prospective classes of cathode materials for a new generation of Li-ion batteries are fluoride-phosphates of transition metals.
The work directed by Prof. Evgeny Antipov (correspondent member of the Russian Academy of Sciences and the head of the MSU Electrochemistry Department) was carried out by a team of MSU research scientists together with their Russian and Belgian colleagues. It was devoted to creation of a new high-power cathode material based on a fluoride-phosphate of vanadium and potassium for Li-ion batteries. The results were published in Chemistry of Materials(current IF — 8.354)
‘The work is based on a simple idea of geometric and crystal-chemical conformity of ionic sublattices,’ — says Stanislav Fedotov, one of the authors, junior research scientist at Electrochemistry Department, Faculty of Chemistry, MSU.
The scientists succeeded to stabilize a unique crystal structure, which provides a fast transport of lithium ions through spatial cavities and channels. Consequently, the suggested cathode material demonstrated high charge/discharge rates (down to 90 seconds) retaining more than 75% of an initial specific capacity. With its morphology and composition optimized, this material may become a serious contender to such well-known and commercialized high-power cathode materials as NaSICON.
According to the authors, the results of the presented work may not only open up ample opportunities in searching and further synthesis of new cathode materials for Li-ion batteries, but also promote the development of a new battery type where a role of a mobile ion (a charge carrier) would be performed by potassium ions instead of lithium.
‘It is assumed that such batteries would not only deliver high energy density, but would also be economically attractive due to a replacement of expensive lithium-containing components with cheaper and hence affordable potassium-containing analogues’ — explains Stanislav Fedotov.
Learn more: New material to enhance battery life
Russian scientists developed the world’s fastest nanoscale photonics switch
International team of researchers from Lomonosov Moscow State University and the Australian National University in Canberra created an ultrafast all-optical switch on silicon nanostructures. This device may become a platform for future computers and permit to transfer data at an ultrahigh speed. The article with the description of the device was published in Nano Letters journal and highlighted in Nature Materials.
This work belongs to the field of photonics – an optics discipline which appeared in the 1960-s, simultaneously with the invention of lasers. Photonics has the same goals as electronics does, but uses photons–the quanta of light–instead of electrons. The biggest advantage of using photons is the absence of interactions between them. As a consequence, photons address the data transmission problem better than electrons. This property can primarily be used for in computing where IPS (instructions per second) is the main attribute to be maximized. The typical scale of eletronic transistors–the basis of contemporary electronic devices–is less than 100 nanometers, wheres the typical scale of photonic transistors stays on the scale of several micrometers. Nanostructures that are able to compete with the electronic structures–for example, plasmonic nanoparticles–are characterized by low efficiency and significant losses. Therefore, coming up with a compact photonic switch was a very challenging task.
Three years ago several groups of researchers simultaneously discovered an important effect: they found out that silicon nanoparticles are exhibit strong resonances in the visible spectrum – the so-called magnetic dipole resonances. This type of resonance is characterized by strong localization of light waves on subwavelength scales, inside the nanoparticles. This effect turned out to be interesting to researches, but, according to Maxim Shcherbakov, the first author of the article published in Nano Letters, nobody thought that this discovery could create a basis for development of a compact and very rapid photonic switch.
Nanoparticles were fabricated in the Australian National University by e-beam lithography followed by plasma-phase etching. It was done by Alexander Shorokhov, who served an internship in the University as a part of Presidential scholarship for studying abroad. The samples were brought to Moscow, and all the experimental work was carried out at the Faculty of Physics of Lomonosov Moscow State University, in the Laboratory of Nanophotonics and Metamaterials.
“In our experimental research me and my colleague Polina Vabishchevich from the Faculty used a set of nonlinear optics methods that address femtosecond light-matter, — explains Maxim Shcherbakov. — We used our femtosecond laser complex acquired as part of the MSU development program”.
Eventually, researches developed a “device”: a disc 250 nm in diameter that is capable of switching optical pulses at femtosecond rates (femtosecond is a one millionth of one billionth of a second). Switching speeds that fast will allow to create data transmission and processing devices that will work at tens and hundreds terabits per second. This can make possible downloading thousands of HD-movies in less than a second.
The operation of the all-optical switch created by MSU researchers is based on the interaction between two femtosecond pulses. The interaction becomes possible due to the magnetic resonance of the silicon nanostructures. If the pulses arrive at the nanostructure simultaneously, one of them interacts with the other and dampers it due to the effect of two-photon absorption. If there is a 100-fs delay between the two pulses, the interaction does not occur, and the second pulse goes through the nanostructure without changing.
“We were able to develop a structure with the undesirable free-carrier effects are suppressed, — says Maxim Shcherbakov. — Free carriers (electrons and electron holes) place serious restrictions on the speed of signal conversion in the traditional integrated photonics.
Our work represents an important step towards novel and efficient active photonic devices– transistors, logic units, and others. Features of the technology implemented in our work will allow its use in silicon photonics. In the nearest future, we are going to test such nanoparticles in integrated circuits”.
Researchers from the Lomonosov Moscow State University discovered a new mechanism of DNA repair, which will help to treat and to prevent diseases in the future
The DNA molecule is chemically unstable giving rise to DNA lesions of different nature. That is why DNA damage detection, signaling and repair, collectively known as the DNA damage response, are needed.
A group of researchers, lead by Vasily M. Studitsky, professor at the Lomonosov Moscow State University, discovered a new mechanism of DNA repair, which opens up new perspectives for the treatment and prevention of neurodegenerative diseases. The article describing their discovery is published in AAAS’ first open access online-only journal Science Advances.
“In higher organisms DNA is bound with proteins in complexes called the nucleosome. Every ~200 base pairs are organized in nucleosomes, consisting of eight histone proteins, which, like the thread on the bobbin, wound double helix of DNA, which is coiled into two supercoiled loops. Part of the surface of the DNA helix is hidden, because it interacts with histones. Our entire genome is packed this way, except for the areas, from which the information is being currently read”, — says Vasily M. Studitsky , who is the leading researcher and the head of the Laboratory of Regulation of Transcription and Replication at the Biological Faculty of the Lomonosov Moscow State University.
The dense packing allows DNA molecule with a length of about two meters to fit into a microscopic cell nucleus, but it makes significant surfaces of the DNA inaccessible for the repair enzymes — the proteins that manage the “repair” of damaged DNA regions. The damage of the DNA, if not repaired, leads to accumulation of mutations, cell death, and to the development of various diseases, including neurodegenerative, e.g. Alzheimer’s disease.
A group of researchers, lead by Vasily M. Studitsky, studied the mechanism of detection of single-stranded DNA breaks at which the connection is lost between nucleotides on one strand in the places where the DNA is associated with histones.
Scientists know quite a lot about the mechanism of the repair. It is known that for the synthesis of a protein, information written in the genetic code, which could be imagined as the manual for its assembly where triples of nucleotides match certain amino acids, should be taken out of the nucleus into the cytoplasm of the cell.
Thin and long strand of the DNA is packed in the nucleus and can tear at the exit to the outside. Moreover, it cannot be sacrificed as the cell’s nuclear DNA is is only present in two copies. Therefore, when it is necessary to synthesize specific protein, small region of DNA is unwound, the two strands are disconnected, and the information on the protein structure with one of the DNA strands is written in form of RNA, single-stranded molecule. The mRNA molecule, which serves as the template for making a protein, is synthesized by the principle of complementarity: each nucleotide pair corresponds to another one.
During the transcription of information (its rewriting into RNA) the RNA polymerase enzyme “rides” on the DNA chain, and stops when it finds the break. Like a proofreader of a text, RNA polymerase after it is stalled, triggers a cascade of reactions, resulting in the repair enzymes fixing the damaged area. At the same time, the RNA polymerase cannot detect discontinuities present in the other DNA strand.