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  • richardmitnick 4:56 pm on May 23, 2016 Permalink | Reply
    Tags: , , Viruses   

    From U Texas at Austin: “Making Virus Sensors Cheap and Simple: New Method Detects Single Viruses” 

    U Texas Austin bloc

    University of Texas at Austin

    23 May 2016
    Marc G Airhart

    Scientists at The University of Texas at Austin have developed a new method to rapidly detect a single virus in urine, as reported* this week in the journal Proceedings of the National Academy of Sciences.

    1
    Researchers at The University of Texas at Austin demonstrated the ability to detect single viruses in a solution containing murine cytomegalovirus (MCMV). The single virus in this image is a human cytomegalovirus, a cousin of MCMV. It was obtained by chilling a sample down with liquid nitrogen and exposing it to high-energy electrons. Image courtesy of Jean-Yves Sgro, U. of Wisconsin-Madison (EMD-5696 data Dai, XH et al., 2013)

    Although the technique presently works on just one virus, scientists say it could be adapted to detect a range of viruses that plague humans including Ebola, Zika and HIV.

    “The ultimate goal is to build a cheap, easy-to-use device to take into the field and measure the presence of a virus like Ebola in people on the spot,” says Jeffrey Dick, a chemistry graduate student and co-lead author of the study. “While we are still pretty far from this, this work is a leap in the right direction.”

    The other co-lead author is Adam Hilterbrand, a microbiology graduate student.

    The new method is highly selective, meaning it is only sensitive to one type of virus, filtering out possible false negatives caused by other viruses or contaminants.

    There are two other commonly used methods for detecting viruses in biological samples, but they have drawbacks. One requires a much higher concentration of viruses, and the other requires samples to be purified to remove contaminants. The new method, however, can be used with urine straight from a person or animal.

    The other co-authors are Lauren Strawsine, a postdoctoral fellow in chemistry; Jason Upton, an assistant professor of molecular biosciences; and Allen Bard, professor of chemistry and director of the Center for Electrochemistry.

    The researchers demonstrated their new technique on a virus that belongs to the same family as the herpes virus, called murine cytomegalovirus (MCMV). To detect individual viruses, the team places an electrode — a wire that conducts electricity, in this case, one that is thinner than a human cell — in a sample of mouse urine. They then add to the urine some special molecules made up of enzymes and antibodies that naturally stick to the virus of interest. When all three stick together and then bump into the electrode, there’s a spike in electric current that can be easily detected.

    The researchers say their new method still needs refinement. For example, the electrodes become less sensitive over time because a host of other naturally occurring compounds stick to them, leaving less surface area for viruses to interact with them. To be practical, the process will also need to be engineered into a compact and rugged device that can operate in a range of real-world environments.

    Support for this research was provided by the National Science Foundation, the Welch Foundation and the Cancer Prevention & Research Institute of Texas.

    *Science paper:
    Enzymatically enhanced collisions on ultramicroelectrodes for specific and rapid detection of individual viruses

    See the full article here .

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    U Texas Arlington Campus

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, The University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

     
  • richardmitnick 2:28 pm on August 28, 2015 Permalink | Reply
    Tags: , , Viruses   

    From CNRS: “Imitating viruses to deliver drugs to cells” 

    CNRS bloc

    The National Center for Scientific Research

    28 AUGUST 2015
    CNRS scientist l Guy Zuber l T +33 (0)3 68 85 41 76 / +33 (0)6 03 75 71 23 l zuber@unistra.fr
    CNRS press l Véronique Étienne l T +33 (0)1 44 96 51 37 l veronique.etienne@cnrs-dir.fr

    Viruses are able to redirect the functioning of cells in order to infect them. Inspired by their mode of action, scientists from the CNRS and Université de Strasbourg have designed a “chemical virus” that can cross the double lipid layer that surrounds cells, and then disintegrate in the intracellular medium in order to release active compounds. To achieve this, the team used two polymers they had designed, which notably can self-assemble or dissociate, depending on the conditions. This work, the result of collaborative efforts by chemists, biologists and biophysicists, is published in the 1st September issue of Angewandte Chemie International Edition.

    Biotechnological advances have offered access to a wealth of compounds with therapeutic potential. Many of these compounds are only active inside human cells but remain unusable because the lipid membrane surrounding these cells is a barrier they cannot cross. The challenge is therefore to find transfer solutions that can cross this barrier.

    By imitating the ability of viruses to penetrate into cells, chemists in the Laboratoire de Conception et Application de Molécules Bioactives (CNRS/Université de Strasbourg) sought to design particles capable of releasing macromolecules that are only active inside cells. To achieve this, these particles must comply with several, often contradictory, constraints. They must remain stable in the extracellular medium, they must be able to bind to the cells so that they be internalized, but they must be more fragile inside the cells so that they can release their content. Using two polymers designed by the team, the scientists succeeded in creating a “chemical virus” that meets the conditions necessary for the direct delivery of active proteins into cells.

    In practice, the first polymer (pGi-Ni2+) serves as a substrate for the proteins that bind to it. The second, recently patented polymer (πPEI), encapsulates this assembly thanks to its positive charges, which bind to the negative charges of pGi-Ni2+. The particles obtained (30-40 nanometers in diameter) are able to recognize the cell membrane and bind to it. This binding activates a cellular response: the nanoparticle is surrounded by a membrane fragment and enters the intracellular compartment, called the endosome. Although they remain stable outside the cell, the assemblies are attacked by the acidity that prevails within this new environment. Furthermore, this drop in pH allows the πPEI to burst the endosome, releasing its content of active compounds.

    Thanks to this assembly, the scientists were able to concentrate enough active proteins within the cells to achieve a notable biological effect. Thus by delivering a protein called caspase 3 into cancer cell lines, they succeeded in inducing 80% cell death.

    The in vitro results are encouraging, particularly since this “chemical virus” only becomes toxic at a dose ten times higher than that used during the study. Furthermore, preliminary results in the mouse have not revealed any excess mortality. However, elimination by the body of the two polymers remains an open question. The next stage will consist in testing this method in-depth and in vivo, in animals. In the short term, this system will serve as a research tool to vectorize2 recombinant and/or chemically modified proteins into cells. In the longer term, this work could make it possible to apply pharmaceutical proteins to intracellular targets and contribute to the development of innovative drugs.

    This work was made possible by the collaboration of biophysicists and biologists. The skills in electron cryomicroscopy available at the Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS/Université de Strasbourg/Inserm), and the expertise in atomic force microscopy of the Laboratoire de Biophotonique et Pharmacologie (CNRS/Université de Strasbourg) enabled highly precise characterization of the molecular assemblies. The Laboratoire Biotechnologie et Signalisation Cellulaire (CNRS/Université de Strasbourg) supplied the recombinant proteins encapsulated in the artificial virus.

    1
    Viktorria Postupalenko

    Notes:

    1To achieve maximum efficacy, the scientists are hoping to combine siRNA (small nucleic acids that specifically target the expression of certain genes) with the proteins, and these could also be delivered using the same particles.

    2Vectorization consists in controlling the distribution of an active substance to a given target by combining it with a vector. This enables delivery of a protein inside a cell via the intermediary of a biocompatible vehicle.

    See the original article for a bibliography.

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    CNRS encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 5:07 pm on August 10, 2015 Permalink | Reply
    Tags: , Infection, , Viruses   

    From NOVA: “One Drop Of Blood Can Reveal Almost Every Virus A Person Has Ever Had” 

    PBS NOVA

    NOVA

    08 Jun 2015
    Allison Eck

    A single drop of blood may contain nearly all the information you need to know about a person’s viral past.

    The new experimental test, called VirScan, opens up a world of possibilities, so much so that its development has been compared to the advent of the electron microscope. Able to detect 1,000 strains of viruses from 206 species, the test analyzes antibodies that the body has made in response to previous viruses.

    The result is a nearly comprehensive record of the human “virome,” and it could eventually give researchers insight into whether or not viruses contribute to chronic diseases and cancer. In other words, scientists may find out what viruses antagonize the immune system by creating antibodies that subvert it—or, they could discover why chemotherapy works well for some people but not for others.

    1
    A very small amount of blood could betray a person’s entire history of viral infection.

    Stephen J. Elledge, senior author of the report published in Science, and his team administered the test to 569 people in the United States, South Africa, Thailand, and Peru. The VirScan results indicated that most people tested had been exposed to about 10 different species of virus, though others had been exposed to as many as 25. People outside the United States had higher rates of exposure, which could be due to a number of factors: sanitation levels, genetic variation, population density, and so on. In the long term, more thorough comparisons between countries’ viral histories could lead to better epidemiological practices across the globe.

    The test can take up to two months to perform right now, but if a company were to acquire it, the whole process may be completed in as few as two or three days, Elledge told The New York Times. And with expedited testing, scientists could study everything from the age at which children acquire various illnesses to how disease has changed throughout history. They may even encounter some unexpected results—in fact, they already have.

    Here’s Denise Grady, writing for The New York Times:

    The initial study had some surprises, Dr. Elledge said. One was “that the immune response is so similar from person to person.” Different people made very similar antibodies that targeted the same region on a virus, he explained.

    Another surprise came from people infected with H.I.V. Dr. Elledge expected their immune responses to other viruses to be diminished. “Instead, they have exaggerated responses to almost every virus,” he said. The researchers do not know why.

    The test has some limitations, but this is certainly a major step forward in scientists’ goal to track the progress and potency of illness and disease all over the world.

    See the full article here.

    Please help promote STEM in your local schools.

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    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

     
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