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Month: March 2013 (page 3 of 8)

03.20.2013

coming back from extinction

(Image: Mike Tyler/ANT Photo Library/Science Source)

Researchers are working to bring a frog that gives birth through its mouth back from extinction. The New Scientist reports:

Habitat destruction drove the gastric-brooding frog (Rheobatrachus silus) to extinction in 1983, but researchers have now created an early frog embryo from frozen specimens with the goal of bringing it back to life.

The gastric brooding frog was the only animal known to give birth through its mouth. It swallows its eggs after laying them, lets them grow for about six weeks, and then dribbles out tadpoles.

To clone the frog, Michael Archer and colleagues at the University of New South Wales in Sydney, Australia, isolated the nuclei from the cells of frogs that had been frozen for 40 years. They transferred them into the eggs of a modern frog, Mixophyes fasciolatus, which then divided several times as if to form an early embryo. The research, which has not yet been published, was presented at a TEDx conference on “de-extinction” in Washington DC last week.

 

03.19.2013

graphene desalination

graphene

Graphene

We’ve mentioned the wonders of graphene a number of times on this blog. Lockheed Martin is now trying to add another: large scale desalination of sea water. They are in the process of developing a prototype to produce drinking water from sea water using a graphene filter. From NBC News:

A defense contractor better known for building jet fighters and lethal missiles says it has found a way to slash the amount of energy needed to remove salt from seawater, potentially making it vastly cheaper to produce clean water at a time when scarcity has become a global security issue.

The process, officials and engineers at Lockheed Martin say, would enable filter manufacturers to produce thin carbon membranes with regular holes about a nanometer in size that are large enough to allow water to pass through but small enough to block the molecules of salt in seawater. A nanometer is a billionth of a meter.

Because the sheets of pure carbon known as graphene are so thin — just one atom in thickness — it takes much less energy to push the seawater through the filter with the force required to separate the salt from the water, they said.

The prototype is expected to be completed by the end of this year. Lockheed Martin hopes to be able to commercialize the product sometime in 2014 or 2015.

03.18.2013

DNA from HeLa cells is sequenced

HeLa cells

HeLa cells viewed under a light microscope

Nature magazine reports that a German lab has sequenced the DNA of HeLa cells. Like cells from most tumors, there are multiple copies of many genes. Excerpt:

Previous work showed that HeLa cells, like many tumors, have bizarre, error-filled genomes, with one or more extra copies of many chromosomes. To get a closer look at these alterations, a team led by Lars Steinmetz, a geneticist at the EuropeanMolecular Biology Laboratory in Heidelberg, Germany, sequenced the popular ‘Kyoto’ version of the cell line and compared the sequence with that of a reference human genome. The team’s results are published in G3.

Steinmetz’s team confirmed that HeLa cells contain one extra version of most chromosomes, with up to five copies of some. Many genes were duplicated even more extensively, with four, five or six copies sometimes present, instead of the usual two.  Furthermore, large segments of chromosome 11 and several other chromosomes were reshuffled like a deck of cards, drastically altering the arrangement of the genes.

Without the genome sequence of Lacks’ healthy cells or that of her original tumor, it is difficult to trace the origin of these alterations. Steinmetz points out that other cervical tumors have massive rearrangements on chromosome 11, so the changes in the HeLa cell may have contributed to Lacks’ tumor.

HeLa cells have been the subject of many biological studies as they are easy to culture and replicate very fast. The cells were originally isolated from an African American woman named Henrietta Lacks, and have been cultured for over 60 years. There is also a fascinating book about the origin of these cells called The Immortal Life of Henrietta Lacks.

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