New device
allows scientists to operate on living cells
London:
Scientists have developed a device that can take a "biopsy" of a
living cell, sampling minute volumes of its contents without killing it. The
new tool, called a nanobiopsy, uses a robotic glass nanopipette to pierce the
cell membrane and extract a volume of around 50 femtolitres, around one per
cent of the cell's contents.
It
will allow scientists to take samples repeatedly, to study the progression of
disease at a molecular level in an individual cell. It can also be used to
deliver material into cells, opening up ways to reprogramme diseased cells.
"This
is like doing surgery on individual cells," said Dr Paolo Actis, from the
Department of Medicine at Imperial College London, who developed the technology
with colleagues at the University of California, Santa Cruz.
"This
technology will be extremely useful for research in many areas. You could use
it to dynamically study how cancer cells are different from healthy cells, or
look at how brain cells are affected by Alzheimer's disease. The possibilities
are immense," Actis said.
To
get inside the cell, the nanopipette is plunged downwards about one micrometre
to pierce the cell membrane. Applying a voltage across the tip makes fluid flow
into the pipette. When the pipette is removed from the cell, the membrane
remains intact and the cell retains its shape.
The
device is based on a scanning ion conductance microscope, which uses a robotic
nanopipette, about 100 nanometres in diameter, to scan the surface of cells.
The
nanopipette is filled with an electrolyte solution and the ion current is
measured inside the tip. When the pipette gets close to a cell membrane, the
ion current decreases.
This
measurement is used to guide the tip across the surface of a sample at a
constant distance, producing a picture of the surface.
In
an initial study published in the journal ACS Nano, the researchers used the
nanobiopsy technique to extract and sequence messenger RNA, molecules carrying
genetic code transcribed from DNA in the cell's nucleus. This allowed them to
see which genes were being expressed in the cell.
They
were also able to extract whole mitochondria - the power units of the cell.
Mitochondria contain their own DNA, and the researchers discovered that the
genomes of different mitochondria in the same cell are different.
Source:
www.zeenewsindia.com/news/health
30.12.2013
Reading a
book may change your brain
Washington:
Scientists have found that reading a novel may change your brain - for days
after going through the book, a new study suggests.
Researchers
at the Emory University have detected what may be biological traces related to
this feeling: Actual changes in the brain that linger, at least for a few days,
after reading a novel.
The
study focused on the lingering neural effects of reading a narrative.
Twenty-one undergraduate students participated in the experiment, which was
conducted over 19 consecutive days. All of the study subjects read the same
novel, 'Pompeii' - a 2003 thriller by Robert Harris that is based on the
real-life eruption of Mount Vesuvius in ancient Italy.
For
the first five days, the participants came in each morning for a base-line fMRI
scan of their brains in a resting state. Then they were given nine sections of
the novel, about 30 pages each, over a nine-day period. They were asked to read
the assigned section in the evening, and come in the following morning.
After
taking a quiz to ensure they had finished the assigned reading, the
participants underwent an fMRI scan of their brain in a non-reading, resting
state.
After
completing all nine sections of the novel, the participants returned for five
more mornings to undergo additional scans in a resting state.
The
results showed heightened connectivity in the left temporal cortex, an area of
the brain associated with receptivity for language, on the mornings following
the reading assignments.
"Even
though the participants were not actually reading the novel while they were in
the scanner, they retained this heightened connectivity," said
neuroscientist Gregory Berns, lead author of the study.
"We
call that a 'shadow activity,' almost like a muscle memory," said Berns.
Heightened
connectivity was also seen in the central sulcus of the brain, the primary
sensory motor region of the brain. Neurons of this region have been associated
with making representations of sensation for the body.
"The
neural changes that we found associated with physical sensation and movement
systems suggest that reading a novel can transport you into the body of the
protagonist," Berns said.
The
neural changes were not just immediate reactions, Berns said, since they
persisted the morning after the readings, and for the five days after the
participants completed the novel.
The
study was published by the journal Brain Connectivity.
Source:
www.zeenewsindia.com/news/health
30.12.2013
Never tell the truth to people who are not worthy of it
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