News: Microscope shows first hours of developing embryo.

Microscope shows first hours of developing embryo

http://news.yahoo.com/s/nm/20081009/sc_nm/us_embryo_digital_3

By Michael Kahn Thu Oct 9, 2:45 PM ET

LONDON (Reuters) - A new high-powered microscope has allowed
scientists to watch a zebrafish develop from a single cell into an
embryo with a beating heart, the first time this has been possible in
vertebrates, researchers said on Thursday.

They created a three-dimensional digital reconstruction of the tiny,
developing fish, which may provide insights into how human organs form
and lead to a better understanding of the genetic underpinnings of
some diseases, they said.

"This is like being able to watch an animal getting a life," said
Joachim Wittbrodt, who led the study published in the journal Science
while at the European Molecular Biology Laboratory in Heidelberg,
Germany.

"You have a clump of cells that are transforming into an embryo with a
beating heart while you are watching."

Scientists have already done this with invertebrates such as worms,
which only have a few hundred cells, but until now replicating the
feat in vertebrates, whose embryos comprise tens of thousands of
cells, has been impossible, he said.

The German team overcame this hurdle by developing a microscope
powerful enough to track tens of thousands of cells at the same time
without requiring the kind of energy that would otherwise destroy or
damage an embryo.

The microscope scans the embryo with what they call a *** of light
along many different directions, allowing a computer to then assemble
a three-dimensional image that over time provides a complete view of
the development, Wittbrodt said.

"The power is in the size and the resolution while at the same time
being extremely gentle on the embryo and extremely fast, which you
need to follow things that are moving," said Wittbrodt, now at the
University of Heidelberg in Germany.

"It's like a huge puzzle and we can see the individual pieces. We see
everything."

Zebrafish, also known as zebra danio, are popular research subjects
because they are cheaper to breed than mice and share a number of
similar biological traits with humans.

To develop into a complex organism, an embryo's cells must divide,
travel around the body and arrange themselves into intricate shapes
and specialized tissues. So far the researchers said they have
identified how some of this cell migration is different to what was
previously believed.

The microscope could also be used to examine mice, chickens and frogs,
they said.

Eventually, such experiments could provide a better understanding of
how tumors spread or why cells sometimes turn against the body in
autoimmune diseases like arthritis, Wittbrodt said.

"There are many implications for humans," he said. "This is just the
starting point."

--
Bob.

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