Adelaide
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How did you start with research?
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So we both started in the Freshman Research Immersion Program, and we were actually
in the same lab for that which is kind of how we got our feet wet with research here.
Then I did independent study following the three semesters of FRI and [Avery] took
a little hiatus and then we both came back and did research in the summer through
the Summer Scholars and Artists Program.
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Michelle
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Adelaide
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What did you do over the summer?
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| I worked with Dr. Jeffrey Schertzer to study biofilms of Pseudomonas aeruginosa. So
for my project I looked at a signalling molecule called the Pseudomonas quinolone
signal, or PQS, and we started by quantifying that molecule over the different stages
of biofilm development to see where it was higher or lower, then we started looking
at some genes and gene pathways that might regulate how much of that PQS we’re seeing
and why we’re seeing that amount of it during the different stages.
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Michelle
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I worked with Dr. Caitlin Light to look at outer membrane vesicles, or OMVs, which
are sort of like missles that the cells launch to kill other bacteria cells or kill
the host cell. They can also act as decoys for antibiotics and they can degrade antibiotics
- they have a whole host of functions. We also quantified the presence of outer membrane
vesicles over the course of biofilm development to see when they were the most prevalent.
What we found is that there’s a distinct relationship, actually, within the projects,
that the amounts of Pseudomonas quinolone signal correlate to the amounts of the outer
membrane vesicles. So we were able to combine that for our research that we presented
in November in California.
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Avery
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Adelaide
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Tell me more about California!
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| After the scholars program was over, we had our meetings and figured where the link
was between our research. Then we got some more data during that following fall semester,
and then in November, presented in Anaheim, California at ABRCMS which is the Annual
Biomedical Research Conference for Minority Students. We combined our summer data
and some of the new stuff we got and then we got to go to California to this conference
and present with a bunch of other disciplines, not just microbiology, also neuroscience
and genetics and environmental sciences and technology.
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Michelle
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We presented our joint project where we showed the relationship between the outer
membrane vesicles, PQS, and another messenger molecule, c-di-GMP. We won an award,
actually, for that and although the conference was for minority students, you don’t
have to be a minority student to present there, but it was just wonderful because
they had a lot of money to provide minority students with transportation and housing
and covering all costs to get there.
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Avery
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Adelaide
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How did your projects end up intersecting?
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We found that c-di-GMP is related to the Pseudomonas Quinolone signal and outer membrane
vesicles and that it is actually inversely related to them, so when you have a greater
presence of that molecule, you have fewer PQS and OMVs, and we thought that this was
extremely interesting because this molecule is able to help control the development
of the biofilm and the progress from an immature biofilm to a mature one. So it’s
a very significant finding for sure.
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Avery
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Adelaide
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So what does this mean for how we look at biofilms and what did you look at in your
research?
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| Biofilms are a huge problem for human health because they are responsible for a
lot of really horrible and hard-to-treat infections like in pneumonia in cystic fibrosis
patients or in infections in burn-wound patients, in conjunctivitis, and especially
for patients who are immunocompromised. So our goal was that if we found different
relationships over these stages of biofilm development, we could better understand
how the biofilm is surviving at these different stages, what defense tactics it uses
during the different stages, so hopefully we know how we can treat them better, where
to attack them from and during what points in an infection.
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Michelle
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We can use this information to understand at what times or at what points in biofilm
development is the biofilm most susceptible to antibiotics - At what point is it releasing
most virulence factors that are hurting the host or other bacterial cells, and this
can help us even in cystic fibrosis because we know how the disease progresses and
how certain Pseudomonas develop in the lungs. We know that disease progression and
then we can understand when it’s best to use specific antibiotics when we’re going
to be dealing with combating these virulence factors.
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Avery
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Adelaide
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So what did you find out about the different stages of development?
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| In general, PQS and OMVs can be kind of lumped together for where there’s more and
less of them during the stages of biofilm development, so we found more of them in
the beginning when the biofilms are starting to attach and then later on towards the
end of the development cycle.
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Michelle
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Specifically, levels of both PQS and OMVs were found to be greatest during the
final stage of development, dispersion, when the cells are leaving the biofilm. Also,
we found that levels of both PQS and OMVs were much lower during the maturation stages
of development.
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Avery
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Adelaide
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So what does the future hold for you two?
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| What I’m doing is basically taking the outer membrane vesicles and analyzing them
to see exactly what proteins they contain, so we want to understand what degradative
enzymes are there, what virulence factors are there, what else is present in an OMV
that’s making it so good at helping the biofilm survive and destroy antibiotics. So
what we’re basically doing is using mass spectrometry to analyze and give us a list
of all the proteins that are present in the outer membrane vesicles from different
stages of development and then we’re comparing them to see when those OMVs are the
same, when are they different, and are there points where they’re specializing in
certain things or trying to combat certain things.
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Avery
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So I’m still in the loop with what [Avery’s] doing, [we] all got pretty close, too,
spending that many semesters with everyone, but I’m in a neuroscience lab now doing
Parkinson’s research, so something very different, but also another good example of
when you’re able to get your foot in the door early on and have all these all opportunities
it opens that door to new different things and different interests.
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Michelle
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