Tag Archives: DNA

Five Things to Know About the Latest Gene Editing Breakthrough

By Ben Panko – In this study, scientists worked with the CRISPR-Cas9 gene editing system, which is kind of like cut and paste on for genes. It’s based on a naturally occurring immune system found in many bacteria species in which the microbes keep a “hit list” of virus DNA in their genomes so they can recognize future dangerous intruders.

If any of that DNA is present, the bacteria deploys enzymes called Cas (CRISPR-associated proteins), which precisely and efficiently snip out that DNA.

This research was notable for its use of viable embryos, or embryos that could likely develop into a baby if allowed to grow, reports Dina Fine Moran for Scientific American.

This is the first time this has ever happened on U.S. soil, but scientists in China have already been pushing the envelope for years. more> https://goo.gl/oxtpXQ

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Scientists Unveil New ‘Tree of Life’

BOOK REVIEW

On the Origin of Species, Author: Charles Darwin.


By Carl Zimmer – A team of scientists unveiled a new tree of life, a diagram outlining the evolution of all living things. The researchers found that bacteria make up most of life’s branches.

And they found that much of that diversity has been waiting in plain sight to be discovered, dwelling in river mud and meadow soils.

In his 1859 book “On the Origin of Species,” Charles Darwin envisioned evolution like a branching tree. The “great Tree of Life,” he said, “fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.”

Ever since, biologists have sought to draw the tree of life. The invention of DNA sequencing revolutionized that project, because scientists could find the relationship among species encoded in their genes.

Recently, Jillian F. Banfield [2] of the University of California, Berkeley and her colleagues decided it was time to redraw the tree. more> http://goo.gl/YCsa2u

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When DNA gets sent to time-out

By Catherine Kolf – Picture the nucleus as a round room filled with double strands of DNA hanging in suspension as they are opened, closed, clipped, patched and read by proteins that come and go.

At the edge of the nucleus, just inside its flexible walls, the lamina meshwork provides shape and support.

But accumulating evidence from the past few years suggests that this meshwork is not just a structure, but is crucial to the cell’s ability to turn large segments of genes off in one fell swoop. It’s as though certain stretches of DNA feel a magnetic pull that keeps them clinging to the lamina in a state of “time-out,” inaccessible to the proteins that could be working on them. more> http://tinyurl.com/mo3dob5

Graphene nanoribbons for €˜reading’ DNA

Direct electrical readout from the graphene transistors is used to detect DNA translocation events. Nanopore, DNA and the graphene nanoribbon are shown in this schematic is not to scale (semimd.com)semimd.com – If we wanted to count the number of people in a crowd, we could make on the fly estimates, very likely to be imprecise, or we could ask each person to pass through a turnstile.

Together with Floriano Traversi, postdoctoral student, and colleagues from the Laboratory of Nanoscale Electronics and Structures, Aleksandra Radenovic from the Laboratory of Nanoscale Biology at EPFL came across the material that turned out to be both the strongest and most resilient: graphene, which consists of a single layer of carbon molecules. The strips of graphene or nanoribbons used in the experiment were produced at EPFL, thanks to the work carried out at the Center for Micro Nanotechnology (CMI) and the Center for Electron Microscopy (CIME). more> http://tinyurl.com/qxprtoy

Graphene nanoribbons for ‘reading’ DNA

Direct electrical readout from the graphene transistors is used to detect DNA translocation events. Nanopore, DNA and the graphene nanoribbon are shown in this schematic is not to scale (semimd.com)semimd.com – If we wanted to count the number of people in a crowd, we could make on the fly estimates, very likely to be imprecise, or we could ask each person to pass through a turnstile.

Together with Floriano Traversi, postdoctoral student, and colleagues from the Laboratory of Nanoscale Electronics and Structures, Aleksandra Radenovic from the Laboratory of Nanoscale Biology at EPFL came across the material that turned out to be both the strongest and most resilient: graphene, which consists of a single layer of carbon molecules. The strips of graphene or nanoribbons used in the experiment were produced at EPFL, thanks to the work carried out at the Center for Micro Nanotechnology (CMI) and the Center for Electron Microscopy (CIME). more> http://tinyurl.com/qxprtoy

Resistance is futile

By Anne Trafton – Cisplatin is a chemotherapy drug given to more than half of all cancer patients. The drug kills cells very effectively by damaging nuclear DNA, but if tumors become resistant to cisplatin they often grow back.

“This is the first study to isolate the effects of a platinum drug in mitochondria, and we were very intrigued to observe that the DNA damage caused by this drug outside of the nucleus were highly toxic,” Shana Kelley, a prof. of biochemistry and pharmaceutical sciences at the Univ. of Toronto, says. more> http://tinyurl.com/kktb6lp

Carnivorous plant throws out “junk” DNA

R&D – Genes make up about 2% of the human genome. The rest consists of a genetic material known as noncoding DNA, and scientists have spent years puzzling over why this material exists in such voluminous quantities.

The clues lie in the genome of the carnivorous bladderwort plant, Utricularia gibba.

It appears that the plant has been busy deleting noncoding “junk” DNA from its genetic material over many generations, the scientists say. This may explain the difference between bladderworts and junk-heavy species like corn and tobacco–and humans. more> http://tinyurl.com/cf7olxg

New key to organism complexity identified

R&D Magazine – The enormously diverse complexity seen amongst individual species within the animal kingdom evolved from a surprisingly small gene pool. For example, mice effectively serve as medical research models because humans and mice share 80% of the same protein-coding genes. The key to morphological and behavioral complexity, a growing body of scientific evidence suggests, is the regulation of gene expression by a family of DNA-binding proteins called “transcription factors.” Now, a team of researchers with the U.S. Department of Energy (DOE)‘s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley has discovered the secret behind how one these critical transcription factors is able to perform–a split personality. more> http://tinyurl.com/bc5ahuu

Researchers increase speed of single-molecule measurements

R&D Mag – As nanotechnology becomes ever more ubiquitous, researchers are using it to make medical diagnostics smaller, faster, and cheaper, in order to better diagnose diseases, learn more about inherited traits, and more. But as sensors get smaller, measuring them becomes more difficult–there is always a tradeoff between how long any measurement takes to make and how precise it is. And when a signal is very weak, the tradeoff is especially big.

A team of researchers at Columbia Engineering, led by Electrical Engineering Professor Ken Shepard, together with colleagues at the University of Pennsylvania, has figured out a way to measure nanopores–tiny holes in a thin membrane that can detect single biological molecules such as DNA and proteins–with less error than can be achieved with commercial instruments. They have miniaturized the measurement by designing a custom integrated circuit using commercial semiconductor technology, building the nanopore measurement around the new amplifier chip. Their research is published in the advance online publication on Nature Methods‘ website on March 18, 2012. more> http://tinyurl.com/6o6l9gx

Homo Politicus: Why Washington Never Learns

Cover of "On Aggression"

Cover of On Aggression

BOOK REVIEW

On Aggression, Author: Konrad Lorenz.

By Ralph Benko – Washington is awash with brains. Here are Think Tanks galore. Here are entire departments of federal agencies given over to nothing but research and analysis of how to solve our national (and local, and world) problems. PhD‘s from every college in the land, perhaps world, are more than happy to drop everything to advise Washington “how to.” Brains galore.

Yes, here is inevitable partisanship. And yes, some Think Tanks were doomed at birth to the role of propagandist instead of rigorous analyst.

Chimpanzees, animals well known to be capable of learning by imitation, copy only higher-ranking members of their species. From a group of these apes, a low-ranking individual was taken and taught to remove bananas from a specially constructed feeding apparatus by very complicated manipulations. When this ape, together with his feeding apparatus, was brought back to the group, the higher-ranking animals tried to take away the bananas which he had acquired for himself, but none of them thought of watching their inferior at work and learning something from him. Then the higher-ranking chimpanzee was removed and taught to use the apparatus in the same way, and when he was put back in the group the other members watched him with great interest and soon learned to imitate him.

Washington is all about social dominance, not competence. more> http://is.gd/ItawTp