Terminalia Chebula in Cystic Fibrosis
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medicinal plants > Terminalia Chebula in Cystic Fibrosis
Terminalia Chebula in Cystic Fibrosis
Achievement of Young Scientist of Indian
Origin
Madhavi Pulakat Gavini: Siemens Competition Silver Medalist
by Amy Hodson Thompson, Cogito, 12.12.2006
It’s not what you know; it’s who you know, right? Well…in
science, not quite. For seventeen-year-old Madhavi Pulakat
Gavini, it was the “what” - her new potential treatment for
Pseudomonas infection - that won her 2nd place at the Siemens
National Competition and a $50,000 college scholarship to add to
her 2006 Intel International Science and Engineering Fair grand
prize win. For Madhavi, “who” is an important factor, but in a
different way.
Pseudomonas aeruginosa (P. aeruginosa), a bacterium that is
common in water, soil and on plants, causes serious or deadly
infections in people who are immune compromised. A friend’s
aunt, who Madhavi came to know well, had cystic fibrosis (CF).
For CF patients, Pseudomonas infection of the lungs is one of
their number one killers. “So I looked up everything I could
about CF when she told me about it,” says Madhavi. “My project
just took off from there.”
Plants vs. Bacteria
Madhavi’s grandfather, an Ayurveda traditional medicine practitioner
and physician in India, encouraged her to test Ayurveda’s
traditional herbal extract treatments against P. aurigenosa. She
selected 10 extracts used to treat lung conditions. “I just grew my
P. aeruginosa strain on the plates and spotted the extracts onto the
plates also to see if any of them could inhibit bacterial growth,”
says Madhavi. “A couple had a pretty small zone of inhibition, but
one particular extract, Terminalia chebula
(Tc), dramatically inhibited the bacteria’s growth.”
“Millions of people suffer from chronic Pseudomonas infections,”
says Madhavi. “An antiseptic spray or inhaler could greatly improve
their quality of life as well as increase their lifespan.”
Madhavi thought she might have something important, but knew she
needed to put aside her extracts for a while. P. aeruginosa, because
it can live in and infect such a wide variety of organisms, from
plants to humans, has different forms. The “rough” form, named for
its appearance on a bacterial plate, is a common strain found in
soil, water, and plants. This is the laboratory strain Madhavi used
in her initial experiments. But in humans, P. aeruginosa is usually
in a “smooth” form, a strain that grows an additional, sticky
polysaccharide coat, and often exists in a complex bacterial
community called a biofilm. Biofilm-forming strains, with their
ability to stick to lung cells and resistance to antibiotics, pose
the biggest threat to humans. Madhavi needed to test her extract on
a biofilm variant.
Up to this point, Madhavi had been pursuing her project for fun over
the summer before her junior year of high school in the biology lab
of Dr. Lakshmi Pulakat, her mother and mentor at Mississippi State
University. When she started at the Mississippi School for
Mathematics and Science (MSMS), she took the project with her. It
was Madhavi’s first year at the boarding school, and she was really
enjoying the atmosphere. “There are students here who are definitely
interested in research, and a lot of them are pretty gifted. So it’s
fun,” says Madhavi.
Madhavi enrolled in MSMS’s dual research program that took her to
MSU for research during the week, and she worked on weekends and
over school breaks too. She had plenty of resources, but she didn’t
have one essential piece for her next step – isolating a biofilm-forming
Pseudomonas. “I read in a couple of different places that in order
to get it to grow biofilm you need what’s called a drip column,”
says Madhavi. “It’s rather expensive so I just wanted to see if I
could come up with another way of manipulating the bacteria so it
will grow the biofilm.” Engineering this new technique became her
independent study project in microbiology class.
Fishing for a Biofilm
Pseudomonas’s biofilm has two main functions:
the first is protection, and the second is to allow the bacterium to
adhere to smooth surfaces like the epithelial cells in our lungs.
The biofilm’s stickiness also makes the cells adhere to plastic. So
Madhavi put plastic micropipette tips in cultures of bacteria
floating in water and growth medium. The stickier biofilm-forming
bacteria grew on the tips, and this allowed Madhavi to “fish” out
few biofilm-forming chromoisolates from the “rough” strain.
Now it was time to test
Terminalia chebula against biofilm-forming P. aeruginosa. When
Madhavi looked at the large zone of inhibition produced by Tc
against her new isolate, she knew that she was looking at something
big. None of the drugs for Pseudomonas infection currently on the
market could do what Madhavi had just accomplished: inhibit both
rough and biofilm-forming P. aeruginosa.
Madhavi’s grandfather never got to hear about Tc’s success, he died
in the spring of 2005. But she still had another influential “who”
to consult in India, her physician and Ayurveda practitioner
grandmother. “She would go back and talk to my mother about her
project,” says Dr. Pulakat. “She wanted to confirm the fact that Tc
was not dangerous.” Madhavi’s grandmother reassured her that the
extract has been used as a medicine for thousands of years, and is
even safe enough to give to infants. Madhavi, hoping to turn Tc into
an effective treatment for P. aeruginosa, set about trying to
determine exactly what molecule in the extract was responsible for
its action.
Unmasking a Molecule
Madhavi painstakingly determined that Tc retained effectiveness even
after 100-fold dilution, after having been sterilized with the
extreme heat and pressure of an autoclave, and after passing through
a 0.1 micron filter. Then, because all her experiments had tested Tc
against new bacterial growth, she pitted it against bacteria that
had already been growing for 5 hours. Within 2 hours of Tc
treatment, the P. aeruginosa was dead. Tc’s ability to kill bacteria
even through a biofilm was confirmed.
Read more about Madhavi in the January/February Medicine and Health
Sciences issue of Imagine Magazine, JHU/CTY's magazine for gifted
students.
Genetic analysis was next. Madhavi exposed growing cells to Tc,
harvested their RNA and compared it to untreated control cell RNA
using microarray analysis. When Madhavi finished analyzing the
nearly 6,000 microscopic bright gene spots on her chips to determine
the levels of RNA for each protein in treated and untreated cells,
the reason behind Tc’s effectiveness was clear. Tc-treated bacteria
had a reduction in expression of genes necessary for biofilm
production, for energy metabolism, and for infecting cells.
Now, Madhavi is working towards developing an inhaler to deliver Tc
to the lungs or a spray to deliver Tc to the skin, surfaces, or
environment as a way to prevent infection. “I envision Tc extract
being used in a multitude of everyday products ranging from
household cleaning supplies, to contact lens solutions to toothpaste
additive,” said Madhavi in the conclusion to her Siemens competition
presentation. She has proved that linking the extract with gold
nanoparticles so that they can be tracked in living animals does not
compromise its action, and her next step is to test the extract in a
mouse cystic fibrosis model. “Millions of people suffer from chronic
Pseudomonas infections,” says Madhavi. “Such an antiseptic spray or
inhaler could greatly improve their quality of life as well as
increase their lifespan.”
If Tc’s promise holds, who knows how many “whos” Madhavi may end up
helping.
Madhavi Pulakat Gavini is a senior at the Mississippi School for
Mathematics and Science. She enjoys late-night hot chocolate parties
in her dorm, has lots of plants, and is a voracious reader. She was
a National History Day finalist in 2005 with a paper about Linus
Pauling and his stance on nuclear weapons. She intends to pursue
biomedical research as a career.
Courtesy : Cogito.Org Online
community for academically talented youth
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