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duminică, 5 august 2012

New Method Could Enable Reprogramming Of Mammalian Cells

Through the assembly of genetic components into "circuits" that perform logical operations in living cells, synthetic biologists aim to artificially empower cells to solve critical problems in medicine, energy and the environment. To succeed, however, they'll need far more reliable genetic components than the small number of "off-the-shelf" bacterial parts now available.

Now a new method developed by Boston University biomedical engineers Ahmad S. Khalil and James J. Collins -- and collaborators at Harvard Medical School, Massachusetts General Hospital and MIT -- could significantly increase the number of genetic components in synthetic biologists' toolkit and, as a result, the size and complexity of the genetic circuits they can build. The development could dramatically enhance their efforts not only to understand how biological organisms behave and develop, but also to reprogram them for a variety of practical applications.

Described in the August 2 online edition of Cell, the method offers a new paradigm for constructing and analyzing genetic circuits in eukaryotes -- or organisms whose cells contain nuclei, which include everything from yeasts to humans. Instead of constructing these circuits with off-the-shelf parts from bacteria and porting them into eukaryotes, as most synthetic biologists do, Khalil and his collaborators have engineered these circuits using modular, functional parts from the eukaryotes themselves.

With funding from the Howard Hughes Medical Institute, the Defense Advanced Research Projects Agency and other sources, the research team built their synthetic genetic circuit parts from a class of proteins, known as zinc fingers, which can be programmed to bind desired DNA sequences. The modularity of the new parts enables a wide range of functions to be engineered, the construction of much larger and more complex genetic circuits than what's now possible with bacteria-based parts, and ultimately, the development of much more powerful applications.

"Our research may lead to therapeutic applications, such as the dynamic modification and control of genes and genetic networks that are important in human disease," said Khalil. Potential medical applications include stem cell therapeutics for a wide variety of injuries and diseases and in-cell devices and circuits for diagnosing early stages of cancer and other diseases. The new method may also equip groups of cells to perform higher-order computational tasks for processing signals in the environment in sensing applications.

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
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'New Method Could Enable Reprogramming Of Mammalian Cells'

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New Computer Method Finds New Uses For Old Drugs

With the cost of putting a single new drug on the pharmacy shelves topping a staggering $1 billion, scientists are reporting development of a way to determine if an already-approved drug might be used to treat a different disease. The technique for repurposing existing medicines could cut drug development costs and make new medicine available to patients faster, they report in ACS' Journal of Medicinal Chemistry.

Sivanesan Dakshanamurthy and colleagues explain that drug companies must limit efforts to market new drugs because the current approach is so expensive, time-consuming and prone to failure. Scientists long have known that drugs already approved for one disease might be effective for others. However, existing methods to identify new uses for old drugs lack accuracy and have other disadvantages. So Dakshanamurthy's team developed a comprehensive new computer method called "Train-Match-Fit-Streamline" (TMFS) that uses 11 factors to quickly pair likely drugs and diseases.

They describe using TMFS to discover evidence that Celebrex, the popular prescription medicine for pain and inflammation, has a chemical signature and architecture suggesting that it may work against a difficult-to-treat form of cancer. Likewise, they found that a medicine for hookworm might be repurposed to cut off the blood supply that enables many forms of cancer to grow and spread. "We anticipate that expanding our TMFS method to the more than 27,000 clinically active agents available worldwide across all targets will be most useful in the repositioning of existing drugs for new therapeutic targets," they said.

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our pharma industry / biotech industry section for the latest news on this subject. The authors acknowledge funding from the National Institutes of Health and the Department of Defense.
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marți, 13 decembrie 2011

Method To Produce Proteins In Laboratory Has Now Been Discovered

Main Category: Biology / Biochemistry
Article Date: 13 Dec 2011 - 1:00 PST

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The most abundant and important molecules in all living organisms are proteins; after all they manage to participate in every single one of life's essential reactions. So it is easy to see why scientists have been making such a fuss trying to learn how to synthesise them in laboratory as this would provide them with a tool of extraordinary potential. Unfortunately, this has not proved easy. But an article just out in the journal Science by Bruno Correia, Mihai Azoitei, William Schief and colleagues from the Biochemistry Department of Washington University and the Institute Gulbenkian of Science in Portugal might have found a solution.

The study describes a new method, which the researchers show to work by synthesising a totally new protein that they think can help in the development of a highly effective vaccine against HIV. This result proves the potential of a protocol that, like Correia points out "can now be used to design any protein whether to treat disease, create food, new sources of energy and even for totally new, not yet imagined, functions".

Synthesis of Proteins in Laboratory - one of the "holy grails" of molecular biology, much talked, much chased but not really achieved. The problem is that the function of a protein is determined by its three-dimensional (3D) structure, which in turn is the result on the physicochemical interactions of its different aminoacids (the "bricks" that form the protein). And to predict the combination of amino acids that will give origin to the 3D structure that have the function we want has proved, so far, too difficult.

The new approach by Correia and Azoitei tries to overcome the problem by using a combination of two well known methods - the so called evolutional protocol, in which proteins with a function similar to the one we want are mutated in an attempt to "evolve" into the desired protein and computational design where computers, departing from the different amino acids' characteristics, attempt to predict their right combination to generate the 3D structure with the function we want. In fact,alone, each of these methods has proven to have impossible limitations for example, in the first case, the number of mutated proteins to test is just too large as even a (small) protein of just 100 amino acids will have more than 20 to the power of 100 different mutations (and there is no guarantee that at least one will be functional). In the second method, the problem resides in our still limited lack of computational power that make accurate predictions except for a few very simple proteins impossible . "Our strategy, on the other hand, works explains Correia because we take the best of each of the 2 methods, using the capacity of the computation programs to explore an enormous space of sequences, and the efficiency of the evolutional method to select those that perform the desired function. "

To test the effectiveness of the new strategy the researchers next tried to create a protein that could serve as basis for a more effective vaccine against HIV then the ones developed so far.

So vaccines work by injecting a dead, attenuated or partial pathogen into the organism we want to protect against the pathogen. This triggers an immune response (without disease) that leaves an "immune memory", that if the organism is one day confronted with the "real thing" , rapidly sets off a fast and powerful immune defence. Anti-viral vaccines have a problem though and this is the reason why there are so few and also why we need a new flu vaccine every year and that is that viruses mutate/change rapidly making "immune memories" too often quickly irrelevant. To overcome the problem Correia and Azoitei used the new method to create a totally new protein, one that contained essential "bits" of HIV , essential in the sense that they are known to never mutate. In this case were used parts of the gp120 protein, the molecule used by the virus to get inside the cells to infect.

So how exactly does the new method works?

To start computational methods are used to find the best protein to transplant the gp120 "bits" into (so a protein with a shape that would not disrupt their 3D structure) and then the resulting molecule is mutated (to make it "evolve"). The proteins obtained (each with a different mutation) are then analysed, again by computers, to find the one with a 3D structure closer to HIV. This assures that the antibodies against the vaccine would be highly effective against the live virus.

"And although we are at early stages concludes Correia we hope that our protein can be used to develop a more effective vaccine against HIV as is one that is not expected to lose "power" (memory) over time. And since the method seems to work the possibilities now are endless, after all from diabetes to haemophilia, to mad cow disease and even cancer or Alzheimer's, the problem is always the same: a defective or absent protein..."

Article adapted by Medical News Today from original press release. Source: Ciência Viva
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joi, 8 decembrie 2011

Evaluation Method Supports Soy Protein As A High-Quality Protein Similar To Meat, Eggs And Dairy

Main Category: Nutrition / Diet
Article Date: 08 Dec 2011 - 1:00 PST

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The importance of protein in the human body is undeniable. However, the idea of what makes a protein a "quality protein" has not been as easy to determine. A new study from the Journal of Agriculture and Food Chemistry takes a closer look at the criteria for determining the quality of a protein.

Traditional methods for determining protein quality have shown animal proteins such as milk and eggs to be high in quality. However, those who are interested in a plant-based diet, or diversifying their proteins, have a more difficult time determining which of their choices are high in quality. Testing methods have shown most plant proteins, such as pea protein, are lower in quality than animal-based proteins.

"Accurate methods for determining protein quality are key to helping people plan a healthful diet," said Glenna Hughes, MS, research scientist at Solae. "Due to the increasing interest in including plant-based proteins in the diet, accurate information on protein quality is needed in scientific literature to help educate consumers and healthcare professionals on this topic."

The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) recommend using the protein digestibility-corrected amino acid score (PDCAAS) as a simple and scientific procedure for assessing protein quality. The PDCAAS methodology focuses on three different parameters: the amount of each essential amino acid the protein contains, how easily the protein can be digested, and by taking both of those parameters into account, whether the protein meets the FAO/WHO's amino acid requirements set for children aged two to five years, as they have higher needs to support growth and development than adults.

According to this study, soy protein has a PDCAAS of 1.00, meaning it is a high-quality protein that meets the needs of both children and adults. Eggs, dairy and meat proteins also have a PDCAAS score of 1.0.

However, soy protein is the only widely available high-quality plant-based protein that achieves this score.

"It's important for people to understand that a plant-based diet is healthy, but that not all proteins are created equal," said Connie Diekman, RD, LD, FADA. "If you are planning a vegetarian diet or want to incorporate plant-based proteins in your diet, understanding protein quality using the PDCAAS scale can allow you to select proteins that score higher, such as soy, to ensure that you are getting the essential amino acids you need."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our nutrition / diet section for the latest news on this subject. For more information on the study, the following is a link to the abstract: http://www.ncbi.nlm.nih.gov/pubmed/22017752.
Solae, LLC Please use one of the following formats to cite this article in your essay, paper or report:

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