[Pharmwaste] Sensing environmental estrogens with glowing yeast

Tenace, Laurie Laurie.Tenace@dep.state.fl.us
Thu, 28 Jul 2005 13:28:16 -0400


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Technology News -

July 27, 2005

Sensing environmental estrogens with glowing yeast

With the prospect of assessing thousands of chemicals as potential human =
and
wildlife endocrine disrupters, the U.S. EPA needs faster analytical =
tests;
current ones can take days to provide results. Enter John Sanseverino, a
research assistant professor in the center for environmental =
biotechnology at
the University of Tennessee, who has engineered a much speedier =
detection
device-yeast that glows in the presence of estrogens.

Current evidence suggests that about 87,000 anthropogenic substances, =
such as
the birth control pill, bisphenol-A, and phthalates, may be disrupting =
the
endocrine systems of humans and wildlife. In 1996, Congress mandated =
that the
EPA begin testing chemicals for possible endocrine disruption activity. =
Since
then, the agency has been working to validate assays.

"The EPA's current system takes 3-5 days," says Sanseverino. The =
agency's
technology relies on mammalian cell lines grown in a medium that changes
color as the cells respond to estrogens. "With ours, we get results in =
2-6
hours." His research will appear in August in the journal Applied and
Environmental Microbiology.

Sanseverino's system relies on human and bacterial genes introduced into
yeast cells. If an estrogenic chemical enters a modified yeast strain, =
then
the compound will bind to an estrogen receptor protein expressed by the =
added
human gene. This receptor-protein complex then binds to a small section =
of
DNA, and this turns on the production of "reporter" bacterial lux genes,
which produce a luminescent protein.

Elaine Francis, the national director for the EPA's pesticide and toxic
research program, which funded Sanseverino, says that this engineered =
yeast
is the type of technology that may lead to faster screening of
endocrine-disrupting chemicals. "The program will probably begin testing =
in
2007," says Francis. (However, others question the entire program; see =
box.)

Francis says that once a chemical has been found to bind with hormone
receptors, EPA then plans to put the substance through a second tier of
testing to uncover any actual endocrine-disrupting effects. "These will =
be
in-depth, multigenerational studies across five possible species, =
including
mammals, fish, and amphibians," she says.

Sanseverino is now engineering a separate yeast line that contains a =
human
androgen receptor to test for chemicals that mimic male hormones, such =
as
testosterone. He is also evaluating whether the amount of light emitted =
by
the yeast correlates with the strength of endocrine activity, so that a =
test
can also quantify the effect.

His future goals are to create an online endocrine sensing system by =
coupling
the glowing yeast with a photodetector hooked up to the Internet. These
remote sensors could then be placed in wastewater treatment plants or =
distant
lakes and streams to give immediate warning of the presence of =
hormone-like
chemicals. -PAUL D. THACKER

=20

Is so much testing needed?

John Sumpter, a professor at Brunel University (U.K.) and a leading =
expert on
endocrine disrupters, says that he does not understand the U.S. EPA's
approach to identifying endocrine disrupters. "In Europe, we have no
intention of screening 1000 chemicals, not to mention 87,000," he says. =
"We
kind of know already what these things will do."

Sumpter says that quantitative structure-activity relationships (QSARs) =
could
be used to do the job. These sophisticated computer models predict =
whether a
compound will bind to an estrogen receptor on the basis of a chemical's =
3-D
molecular structure.

"When you have a structure that you see might bind with one of these
receptors, you could then test it," says Ana Soto, a professor of =
anatomy and
cellular biology at Tufts University, who echoes some of Sumpter's =
thoughts.

However, other researchers point out that a simple computer evaluation =
of a
chemical's structure might miss some substances. Shane Snyder, R&D =
project
manager with the Southern Nevada Water Authority, has worked on an EPA
endocrine disruptors advisory committee and says that chemicals can =
sometimes
be modified once they enter a body.

Metabolic processes may inactivate a chemical or change the substance so =
that
it begins to mimic a hormone. "If a QSAR predicts estrogen-receptor =
binding,
but the compound is degraded in saliva (for instance), the compound =
would
have no biological effect," he says. -PDT

http://pubs.acs.org/subscribe/journals/esthag-w/2005/jul/tech/pt_yeast.ht=
ml

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Laurie J. Tenace

Environmental Specialist

Florida Department of Environmental Protection

2600 Blair Stone Road, MS 4555

Tallahassee, Florida 32399-2400

PH: (850) 245-8759

FAX: (850) 245-8811

Laurie.Tenace@dep.state.fl.us

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view our mercury web pages at:=20

http://www.dep.state.fl.us/waste/categories/mercury/default.htm

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<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Technology News =
&#8211;</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>July 27, 2005</span></font></p>

<p class=3DMsoNormal><b><font size=3D6 face=3D"Times New Roman"><span
style=3D'font-size:24.0pt;font-family:"Times New =
Roman";font-weight:bold'>Sensing
environmental estrogens with glowing yeast</span></font></b></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>With the prospect of assessing =
thousands
of chemicals as potential human and wildlife endocrine disrupters, the =
U.S. EPA
needs faster analytical tests; current ones can take days to provide =
results.
Enter John Sanseverino, a research assistant professor in the center for
environmental biotechnology at the University of Tennessee, who has =
engineered
a much speedier detection device&#8212;yeast that glows in the presence =
of
estrogens.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Current evidence suggests that =
about
87,000 anthropogenic substances, such as the birth control pill, =
bisphenol-A,
and phthalates, may be disrupting the endocrine systems of humans and =
wildlife.
In 1996, Congress mandated that the EPA begin testing chemicals for =
possible
endocrine disruption activity. Since then, the agency has been working =
to
validate assays.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>&#8220;The EPA&#8217;s current =
system
takes 3&#8211;5 days,&#8221; says Sanseverino. The agency&#8217;s =
technology relies
on mammalian cell lines grown in a medium that changes color as the =
cells
respond to estrogens. &#8220;With ours, we get results in 2&#8211;6
hours.&#8221; His research will appear in August in the journal <i><span
style=3D'font-style:italic'>Applied and Environmental =
Microbiology</span></i>.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Sanseverino&#8217;s system relies =
on
human and bacterial genes introduced into yeast cells. If an estrogenic
chemical enters a modified yeast strain, then the compound will bind to =
an
estrogen receptor protein expressed by the added human gene. This
receptor-protein complex then binds to a small section of DNA, and this =
turns
on the production of &#8220;reporter&#8221; bacterial lux genes, which =
produce
a luminescent protein.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Elaine Francis, the national =
director for
the EPA&#8217;s pesticide and toxic research program, which funded =
Sanseverino,
says that this engineered yeast is the type of technology that may lead =
to
faster screening of endocrine-disrupting chemicals. &#8220;The program =
will
probably begin testing in 2007,&#8221; says Francis. (However, others =
question
the entire program; see box.)</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Francis says that once a chemical =
has
been found to bind with hormone receptors, EPA then plans to put the =
substance
through a second tier of testing to uncover any actual =
endocrine-disrupting
effects. &#8220;These will be in-depth, multigenerational studies across =
five
possible species, including mammals, fish, and amphibians,&#8221; she =
says.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Sanseverino is now engineering a =
separate
yeast line that contains a human androgen receptor to test for chemicals =
that
mimic male hormones, such as testosterone. He is also evaluating whether =
the
amount of light emitted by the yeast correlates with the strength of =
endocrine
activity, so that a test can also quantify the effect.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>His future goals are to create an =
online
endocrine sensing system by coupling the glowing yeast with a =
photodetector
hooked up to the Internet. These remote sensors could then be placed in
wastewater treatment plants or distant lakes and streams to give =
immediate
warning of the presence of hormone-like chemicals. &#8212;PAUL D. =
THACKER</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>&nbsp;</span></font></p>

<p class=3DMsoNormal><b><font size=3D5 face=3D"Times New Roman"><span
style=3D'font-size:18.0pt;font-family:"Times New =
Roman";font-weight:bold'>Is so
much testing needed?</span></font></b></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>John Sumpter, a professor at =
Brunel
University (U.K.) and a leading expert on endocrine disrupters, says =
that he
does not understand the U.S. EPA&#8217;s approach to identifying =
endocrine
disrupters. &#8220;In Europe, we have no intention of screening 1000 =
chemicals,
not to mention 87,000,&#8221; he says. &#8220;We kind of know already =
what
these things will do.&#8221;</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Sumpter says that quantitative
structure-activity relationships (QSARs) could be used to do the job. =
These
sophisticated computer models predict whether a compound will bind to an
estrogen receptor on the basis of a chemical&#8217;s 3-D molecular =
structure.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>&#8220;When you have a structure =
that you
see might bind with one of these receptors, you could then test =
it,&#8221; says
Ana Soto, a professor of anatomy and cellular biology at Tufts =
University, who echoes some of Sumpter&#8217;s =
thoughts.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>However, other researchers point =
out that
a simple computer evaluation of a chemical&#8217;s structure might miss =
some
substances. Shane Snyder, R&amp;D project manager with the Southern =
Nevada
Water Authority, has worked on an EPA endocrine disruptors advisory =
committee
and says that chemicals can sometimes be modified once they enter a =
body.</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>Metabolic processes may inactivate =
a
chemical or change the substance so that it begins to mimic a hormone.
&#8220;If a QSAR predicts estrogen-receptor binding, but the compound is
degraded in saliva (for instance), the compound would have no biological
effect,&#8221; he says. &#8212;PDT</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'><a
href=3D"http://pubs.acs.org/subscribe/journals/esthag-w/2005/jul/tech/pt_=
yeast.html">http://pubs.acs.org/subscribe/journals/esthag-w/2005/jul/tech=
/pt_yeast.html</a></span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;font-family:"Times New Roman"'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Laurie
J. Tenace</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Environmental
Specialist</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Florida
Department of Environmental Protection</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>2600</span></font><font
 size=3D2><span style=3D'font-size:10.0pt'> Blair Stone Road, =
MS</span></font><font
size=3D2><span style=3D'font-size:10.0pt'> 4555</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Tallahassee</span></font><font
 size=3D2><span style=3D'font-size:10.0pt'>, Florida =
32399-2400</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>PH:
(850) 245-8759</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>FAX:
(850) 245-8811</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'><a
href=3D"mailto:Laurie.Tenace@dep.state.fl.us">Laurie.Tenace@dep.state.fl.=
us</a></span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>view
our mercury web pages at: </span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'><a
href=3D"http://www.dep.state.fl.us/waste/categories/mercury/default.htm">=
http://www.dep.state.fl.us/waste/categories/mercury/default.htm</a></span=
></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:11.0pt'>&nbsp;</span></font></p>

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