More complex organisms are composed of millions of cells, so it is essential to know to understand the life sciences.

The formation of the earth began about 4.6 billion years, and from there slowly and step by step was formed everything we see at this time.

Humans are composed of more than 200 different cells, specialized in various functions that enable the functioning of our body with a set ready to face a world

The current research picks up where a study conducted last year left off. That research determined the structure of a piece of protein machinery called the "origin recognition complex" (ORC), which identifies and binds to DNA-replication "start" sites. When joined by a replication initiation factor, the ORC undergoes conformational changes that set in motion the whole replication process. The new study reveals how this previous structure recruits and interacts with the enzyme that eventually unwinds the DNA double helix into two separate strands.

Catching the molecular machinery in action is no simple task. Intermediate protein structures exist on fleeting timescales, and the interactions take place at the atomic level. Researchers working in Speck and Stillman's labs used tools of molecular biology and biochemistry to slow down the process.

They purified and then remixed together pieces of the protein puzzle (including the origin recognition complex, the replication initiator, the core of the helicase, and other components) and a slow-acting energy agent so the energy-requiring reaction is unable to proceed to completion.

Like dancers paused in place by a sudden stop of music, the molecular components "froze" partway through the helicase recruitment/assembly process.

Jingchuan Sun at Brookhaven then literally froze the samples, embedding them in ice, and took tens of thousands of pictures with a cryo-electron microscope. He then used computer software to reconstruct the 3-D structure from the 2-D electron microscope pictures.

Comparing the new structure (components of the helicase bound to the origin recognition complex) with the structures of the ORC produced last year revealed conformational changes. Binding of the helicase core components appears to shift the ORC into a spiral conformation that closely matches the spiral shape of double-stranded DNA.

It is really wonderful as they could observe the behavior of these proteins, as well as took benefit for subjects such as cell division can currently serve in the treatment of many diseases.

Also, is very important how each of the people committed to the struggle for finish work research and thus show excellent results, which are not easy but not impossible.

The answer, says Dr. Mak in research published today in the Journal of Experimental Medicine, is found in the way estrogen rushes in to "rescue" cells whose healthy functioning has been altered by oxidative stress, a well-established factor in cancer development. Without estrogen, these damaged cells would die a natural death and not threaten the host in the long run, but with estrogen, these cells not only survive, but thrive and develop breast and ovarian cancers. In Canada, about 1,000 women die from BRCA1-related cancers every year.

The research published today illuminates the interplay between the tumour suppressor gene BRCA1 and a master regulator -- Nrf2 -- that governs the antioxidant response in cells. In healthy cells of all tissues, BRCA1 normally repairs damaged DNA in partnership with Nrf2, and so the cells are protected against oxidative stress. However, when the BRCA1 gene is mutated, it loses its ability to repair DNA and can no longer partner with Nrf2, shutting off its antioxidative function.

In most tissues, the resulting oxidative stress kills the cells that have lost BRCA1 function. However, in breast and ovary, the estrogen present in these tissues can swoop in to rescue BRCA1-deficient cells by triggering a partial turn-on of Nrf2. These unhealthy cells gain just enough resistance to oxidative stress to keep them alive and growing. Over time, these surviving BRCA1-deficient cells accumulate more and more mutations due to their lack of ability to repair DNA damage, eventually leading to the development of cancer in these tissues.

The missing piece of the puzzle was estrogen and its unexpected effects on the antioxidant regulation mediated by Nrf2.

The research published today was funded by grants from the Canadian Institutes of Health Research, the Ontario Ministry of Health and Long-term Care, and The Princess Margaret Cancer Foundation.

At present, the breast and ovarian cancer affects many women in the world, because this is very important, that prove predisposition forms in order to "prevent“.

However, this study goes into an ethical and society, because it can be a way to prevent cancer, but also pitted against a world that makes facile way to deliver it to the youth especially, is very difficult.

At this time, medical advances from all eyes but likewise advancing disease, so if you want to promote health, we find every day a new thing so that way we can work with the prevention and treatment of all the various conflicts that appear every day.

In a medical career will always find puzzles to solve, issues to investigate and to clarify doubts. all these studies being conducted continuously help us make our work simpler and we understand there are also advances in all areas

Doctors face daily with diseases easily spread in the population, and yourself from terminal characteristics for life, for this, do research and learn about these is not far from reality, and never left over any issue that has to do with these

Be aware about new treatment options and disease prevention, serves not only to learn, and is reflected in dealing with the sick and the way it seeks the welfare for all, this is the reason which the doctor has to study all his life.

also, is of outstanding importance to know about more concurrent diseases in the population, so to be clear, also need to know about every part of our body and its functioning.

Daily, in a medical career and in many others, we have to face anything new coming out every day, for this, it is useful to establish contact with the daily news that is reflected in our knowledge.

Not only important for the medical, also helps to enrich our language and our way of life, which are required to complete a professional.

Editorial Staff. Science Daily, you source for the latest research news [revista en  Internet][citado  2013  Jul 16]. Disponible en: http://www.sciencedaily.com/releases/2013/07/130714160514.htm

Editorial Staff. Science Daily, you source for the latest research news [revista en  Internet][citado  2013  Jul 16]. Disponible en: http://www.sciencedaily.com/releases/2013/07/130715105118.htm

MARTINEZ SÁNCHEZ, Lina María. Biología Molecular. 7. Ed. Medellín: UPB. Fac. de Medicina, 2012. 7-8 p.