Scope shows developing embryo
2008-10-10 20:06
London - 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.
Sheet of light
The microscope scans the embryo with what they call a sheet
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 specialised 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 tumours 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."