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By Emma Patten-Hitt
NEW
YORK (Reuters Health) - A soil bacterium that causes lumpy
tumors on plants may be able to 'jump kingdoms' and insert
its tumor-causing DNA into human cells, new research findings
suggest.
The
bacterium, called Agrobacterium tumefaciens, contains a
small piece of DNA that can insert itself into the DNA of
a host cell and initiate a tumor. Agrobacterium is already
known to cause plant tumors, but researchers wanted to test
whether the bacterium could similarly insert its DNA into
human cells.
Dr.
Vitaly Citovsky from the State University of New York, Stony
Brook, and colleagues found that the plant bacterium was
able to attach to human cells and insert its DNA into human
cells just as it does with plant cells.
Whether
Agrobacterium is dangerous to humans is unclear, however.
``Here (insertion of DNA into) human cells has been observed
in laboratory conditions; whether it may be relevant biologically
in nature remains unknown,'' the researchers note in the
current early edition of the Proceedings of the National
Academy of Sciences (news - web sites).
``Our
experiments were done under laboratory conditions,'' Citovsky
told Reuters Health. ``In nature, I do not believe Agrobacterium
represents a danger. However, for people who work with large
concentrations of this bacterium, for example researchers
or certain agricultural workers who deal with heavily infected
plants, it may be prudent to be careful or at least aware,''
he said.
One
implication of this study, said Citovsky, is the potential
for genetic flow between bacteria and animals. Another implication
is that the basic biochemical and cellular reactions involved
in the Agrobacterium-plant cell interaction probably exist
in the animal kingdom as well.
``Presently,
it appears that Agrobacterium is the only example of trans-kingdom
DNA transfer,'' Citovsky said. ``I do not rule out other
possibilities but there are no data. Of course, what can
be done once, can almost always be done again,'' he added.
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