Are viruses alive? Viruses have found an ingenious way of perpetuating themselves, without ever being truly alive.

bacteriophage T4

Unlike most living organisms, they can be frozen or boiled, but then explode into life if conditions are right. Viruses enter other organisms' cells and take over their machinery, making copies of themselves, but they can't "reproduce" on their own.

Using a combination of imaging techniques, researchers have determined that some viruses infect cells by piercing the cells' outer membranes, digesting the walls and injecting virus DNA into the cell. These findings explain how viruses invade cells and offer a new way to deliver genes and drugs directly into cells.

The study, funded by the National Science Foundation's (NSF) Biological Sciences Directorate, was led by researchers Michael Rossman of Purdue University and Vadim Mesyanzhinov of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry in Moscow. The team studied the structure of the bacteriophage T4—a virus that attacks the familiar microbe E. coli.

Fifteen years ago, the proteins that Princeton neuroscientist Lisa Boulanger has staked her career on weren't even thought to exist in the brain. Known as major histocompatibility complex class I, or MHCI proteins, they are essential for an adaptive immune response. The thought at the time was that the brain was an area of the body where the immune system wasn't active. It simply wouldn't need MHCs.

genecutting.jpgA simple, precise and inexpensive method for cutting DNA to insert genes into human cells could transform genetic medicine, making routine what now are expensive, complicated and rare procedures for replacing defective genes in order to fix genetic disease or even cure AIDS.

Discovered last year by Jennifer Doudna and Martin Jinek of the Howard Hughes Medical Institute and University of California, Berkeley, and Emmanuelle Charpentier of the Laboratory for Molecular Infection Medicine-Sweden, the technique was labeled a “tour de force” in a 2012 review in the journal Nature Biotechnology.

That review was based solely on the team’s June 28, 2012, Science paper, in which the researchers described a new method of precisely targeting and cutting DNA in bacteria.

microbefuels.jpgA humble soil bacterium called Ralstonia eutropha has a natural tendency, whenever it is stressed, to stop growing and put all its energy into making complex carbon compounds. Now scientists at MIT have taught this microbe a new trick: They’ve tinkered with its genes to persuade it to make fuel — specifically, a kind of alcohol called isobutanol that can be directly substituted for, or blended with, gasoline.

Harvard Stem Cell Institute (HSCI) researchers at the Joslin Diabetes Center (JDC) have taken a major step toward eventually understanding — and perhaps slowing — the aging process.

In a series of careful experiments, Amy J. Wagers and colleagues have demonstrated that the stem cells of old mice exposed to certain factors present in blood from young mice begin to act like young stem cells, with the process driven by signals from another type of cell nearby in the bone. In fact, not only do the blood stem cells begin to take on characteristics of younger cells, but the tissues of old mice exposed to this yet-to-be-identified factor or factors appear to be much more “youthful.

An international team of scientists has rescued visual function in laboratory rats with eye disease by using cells similar to stem cells. The research shows the potential for stem cell-based therapies to treat age-related macular degeneration in humans.

A team led by Dennis Clegg, of UC Santa Barbara, and Pete Coffey, of University College London (UCL), published their work in two papers, including one published this week in the journal PloS One. The first paper was published in the October 27 issue of the journal Stem Cells.

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