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Messages - drkamruzzaman

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Nice one

Informative post..

A group of Russian scientists have discovered a new method of DNA repair which may be able to prevent and cure neurodegenerative diseases, such as Alzheimer’s or Parkinson’s and even stop the process of cell death.
The research team led by Vasily M. Studitsky, professor at the Lomonosov Moscow State University, published their findings in an article “Structure of transcribed chromatin is a sensor of DNA damage” in the Science Advances journal.
“Early detection and repair of damaged DNA is essential for cell functioning and survival,” says the study.
The paper raises the question of single-strand breaks (SSBs) which are called in the research “common DNA damages generated during various processes of cell metabolism.”
“Unrepaired SSBs can interfere with transcription, replication, and DNA repair; induce accumulation of double-stranded DNA breaks; increase genomic instability and apoptosis [process of programmed cell death]; and lead to severe neurodegenerative diseases.” Alzheimer’s, Parkinson’s disease and spinal muscular atrophy are examples of such diseases.

A worker at a nuclear fuel processing plant noticed something suspicious in a routine analysis of uranium obtained from a normal mineral source from Africa. As is the case with all natural uranium, the material under study contained three isotopos- ie three forms with different atomic masses: uranium 238, the most abundant variety; uranium 234, the rarest; and uranium 235, the isotope that is coveted because it can sustain a nuclear chain reaction. For weeks, specialists at the French Atomic Energy Commission (CEA) remained perplexed
Elsewhere in the earth’s crust, on the moon and even in meteorites, we can find uranium 235 atoms that makes up only 0.720 percent of the total. But in the samples that were analyzed, which came from the Oklo deposit in Gabon, a former French colony in West Africa, the uranium 235 constituted only 0.717 percent. That small difference was enough to alert French scientists that there was something very strange going on with the minerals. These small details led to further investigations which showed that least a part of the mine was well below the normal amount of uranium 235: some 200 kilograms appeared to have been extracted in the distant past, today, that amount is enough to make half a dozen nuclear bombs. Soon, researchers and scientists from all over the world gathered in Gabon to explore what was going on with the Uranium from Oklo.
What was fund in Oklo surprised everyone gathered there, the site where the uranium originated from is actually an advanced subterranean nuclear reactor that goes well beyond the capabilities of our present scientific knowledge. Researchers believe that this ancient nuclear reactor is around 1.8 billion years old and operated for at least 500,000 years in the distant past. Scientists performed several other investigation at the uranium mine and the results were made public at a conference of the International Atomic Energy Agency. According to News agencies from Africa, researchers had found traces of fission products and fuel wastes at various locations within the mine area.
Incredibly, compared with this huge nuclear reactor, our modern-day nuclear reactors are really not comparable both in design and functionality. According to studies, this ancient nuclear reactor was several kilometers long. Interestingly, for a large nuclear reactor like this, thermal impact towards the environment was limited to just 40 meters on all sides. What researchers found even more astonishing, are the radioactive wastes that have still not moved outside the limits of the site as they are still held in place tanks to the geology of the area.

For more:

Teaching & Research Forum / New mechanism of DNA repair
« on: July 11, 2015, 10:32:26 AM »
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.
"We have shown, not yet in the cell, but in vitro, that the repair of breaks in the other DNA chain, which is "hidden" in the nucleosome, is still possible. According to our hypothesis, it occurs due to the formation of special small DNA loops in the nucleosome, although normally DNA wounds around the histone "spool" very tightly",—says Vasily M. Studitsky,—"The loops form when the DNA is coiled back on nucleosome together with polymerase. RNA polymerase can "crawl" along the DNA loops nearly as well as on histone-free DNA regions, but when it stops near locations of the DNA breaks, it "panics", triggering the cascade of reactions to start DNA "repairs".
During the experiment, special sites, where single-stranded breaks can be introduced by adding specific enzymes in a test tube, were inserted into the DNA. Then a single nucleosome transcribed by a single RNA molecule was studied. In this model system, which was developed in 2002 by the same group of scientists, histones were assembled on the molecule with an accuracy within one nucleotide. Having specially introduced breaks at precise locations on the DNA, the researchers examined the impact of breaks on the progression of the RNA polymerase. It turned out that only in nucleosomes, rather than in the histone-free DNA, the enzyme stopped, when the break was present in the other DNA strand. Wherein it did not stop before the break, but immediately after it. It was difficult enough to understand the mechanism that allows it to notice the damage at the "back" of RNA polymerase, as if it had "eyes on the back of the head", although, obviously, it does not have neither one nor the other.
The analysis of breaks in different positions allowed to hypothesize that stalling of RNA polymerase is caused by the formation of the loop, which blocks movement of the enzyme. The findings open up a new direction for the work on the subject of DNA repair.
Previously the role of chromatin considered passive as scientists thought the DNA repair is possible only on histone-free DNA. However, professorr Vasily M. Studitsky and his colleagues found that the thread can be repaired without complete unwinding of DNA "coils". The highly conserved histones play an important role in this process as changes in their structure are rejected by natural selection. Moreover, the high level of protein conservation just assumes its active participation in many processes.
Furthermore, the models proposed by the scientists first time ever explains the role of the so-called topological locks, which are formed during the passage of any enzyme along the DNA when it meets a nucleosome.
"In terms of applied science discovery of a new mechanism of reparation promises new prospective methods of prevention and treatment of diseases. We have shown that the formation of loops, which stop the polymerase, depends on its contacts with histones. If you make them more robust, it will increase the efficiency of the formation of loops and the probability of repair, which in turn will reduce the risk of disease. If these contacts are destabilized, then by using special methods of drug delivery you can program the death of the affected cells",—Vasily Studitsky concluded, adding that the process of development and testing of such drugs, of course, requires considerable time.

Informative post

Textile Engineering / Re: Textile Design
« on: July 11, 2015, 09:58:43 AM »
Interesting and informative one.

Good post..

Informative post...

Textile Engineering / Re: Viscose- the regenerated fiber
« on: July 11, 2015, 08:58:01 AM »
Interesting post...

Faculty Sections / 17 Reasons Why You Need a Mango Every Day
« on: July 08, 2015, 09:59:24 PM »
Mangoes may very well be the king of all fruits. They fight cancer, alkalize the body, aid in weight loss, regulate diabetes, help digestion, clean your skin, and make the perfect snack. Here are 17 healthy reasons why you should be eating a mango every day.
1. Fights cancer
Antioxidants like quercetin, isoquercitrin, astragalin, fisetin, gallic acid and methylgallat present in mango protect the body against colon, breast, leukemia and prostate cancers.
2. Keeps cholesterol in check
Mango has high level of vitamin C, pectin and fibres that help to lower serum cholesterol levels. Fresh mango is a rich source of potassium, which is an important component of cell and body fluids that helps to control heart rate and blood pressure.
3. Skin cleanser
Mangoes help you unclog your pores and add freshness to the face. Mangoes are applicable to any skin type. They help clear clogged pores that cause acne. Just slice a mango into thin pieces and keep them on your face for 10 to 15 minutes and then take bath or wash your face and see the results.
4. Alkalizes the body
According to natural health, mango is rich in tartaric acid, malic acid and traces of citric acid that primarily help in maintaining the alkali reserve of the body.
5. Weight loss
Mango has a lot of vitamins and nutrients that help the body feel fuller. Also, the fibrous fruit boosts the digestive function of the body by burning additional calories, helping in weight loss.
6. Regulates diabetes
Not only the fruit but the leaves of mangoes are healthy too. For people suffering from diabetes, just boil 5-6 mango leaves in a vessel, soak it through night and drink the filtered decoction in the morning. This is helps in regulating your insulin levels.
Mango has a low glycemic index (41-60) so going a little overboard will not increase your sugar levels.
7. Aphrodisiac
Mango has aphrodisiac qualities and is also called the ‘love fruit’. Mangoes increase the virility in men. Vitamin E, which is abundantly present in mangoes, helps to regulate sex hormones and boosts sex drive.
8. Eye care
Did you know that mango is rich in vitamin A. One cup of sliced mangoes equals 25% intake of your daily need of vitamin A. Mangoes help in promoting good eye sight, fights dry eyes and also prevent night blindness.
9. Helps in digestion
Mango contains enzymes that help in breaking down protein. The fibrous nature of mango helps in digestion and elimination. It is is rich in pre-biotic dietary fibre, vitamins and minerals.
10. Heat stroke
When the sun is bogging you down this summer, just chop of a mango in a juicer; add a little water and a tbsp of sugar free or honey. This juice will instantly cool you down and prevent heat stroke.
11. Strengthens your immune
The deadly combination of vitamin C, vitamin A and 25 different kinds of carotenoids keep your immune system healthy.
12. Body scrub
Make a paste of mashed mango, honey and milk and use as a body scrub, you will feel that your skin is tender and smooth.
13. Aids concentration and memory
Studying for exams? This fruit is rich in glutamine acid– an important protein for concentration and memory. Feed mangoes to children who find it difficult to concentrate on studies.
14. High iron for women
Mango is rich in iron, hence it is a great natural solution for people suffering from anemia. Menopausal and pregnant women can indulge in mangoes as this will increase their iron levels and calcium at the same time.
15. Reduces Kidney Stones
In Chinese medicine, mangoes are considered sweet and sour with a cooling energy also capable of reducing the risk of kidney stone formation.
16. Perfect Snack
Instead of snacking on unhealthy chips and cookies, why not feast on slices of mangoes instead. They are perhaps one of the tastiest dehydrated fruits of all.
17. Stomach Tonic
Before going to bed put some 10 or 15 mango leaves in warm water and close it with lid. The next day morning filter the water and drink it in empty stomach. Do this regularly.

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