Hi, I'm Alex. I'm part of an international,
interdisciplinary group of researchers who've come
together to work in the field of synthetic biology.
Bacteria can produce proteins called adhesins
These allow the bacteria to stick to surfaces and to
each other, forming biofilms. Gum disease, catheter contamination,
and implant contamination are all medical consequences
of biofilm formation. There are also environmental consequences
such as metal corrosion. However, if we could control when
and where these proteins are expressed, we could use
this for good purposes. For example, imagine we have
devised a method for extracting an environmental
pollutant. We could implement this method into a
single bacteria. However, if one of the intermediate substances
in the process is harmful to that bacteria, the process can't
be carried through. Instead, we could implement several
strains of bacteria, each able to carry out a single
step in the process, passing along the intermediate substances
to the next bacteria. In this way, we could overcome the problem.
In order to control what our bacteria sticks to, we removed
cell surface proteins such as adhesins and flagella.
Into this naked strain, we could implant adhesin genes of
our desire. This allows us to control exactly what
our bacteria will stick to.
Hi, I am Dharmik and this is our experiment.
Our strategy is to use a three component protein
which can be expressed on the cell surface.
A small region on our protein is recognized by the secretion
channel and allows it to pass through the inner membrane.
When a part of the protein anchors itself through the cellular
membrane and feeds the extracellular component out of
the cell. The first step in our experiment is to label our
naked bacteria so that we can visualize the interactions
between cells expressing different adhesins.
We transformed the cells with either GFP or mCherry
carrying plasmids. To do this, we used two different
techniques, mating and electroporation.
We utilized a system which transferred the fluorescence genes
from the plasmid to the bacterial genome. Now we have
one strain which fluoresces green and one red.
We checked the fluorescence genes inserted in the correct
part of the genome or not using the colony PCR.
Now that we have two identifiable strains, we can start
thinking about the adhesins. These are the plasmids
containing our different adhesins. We are testing two different
types of anchor systems. These are the auto-transporters
and these are the intimins. We introduced these into our
bacteria by electroporation. We then checked that the
electroporation was successful by plasmid extraction or
PCR. If everything has been successful, we can induce our
bacteria to express the adhesins. We can verify correct expression
and localization through the cell surface using Western blot and
fluorescence microscopy. Hi, I'm Yong.
I come from the University of Hong Kong and
I'm a member of this synthetic biology team.
For this project, there is still a lot of research, interesting
research to be undertaken. It would be useful to be able to
produce an interesting signal when adhesion occurs.
From this, we can start building the complex behavior
that is our goal. In a similar manner, linking the expression of
the adhesins to more diverse biosensors would enable this
system to be useful for many more settings.
Being able to direct or at the very least predict,
the positioning of adhesins on the cell's membrane
would enable more precise community structures, which may
improve the importance for certain applications. We are also
unsure how many different types of adhesins we can produce
in a single cell while maintaining a healthy cell and predictable
behaviors. This work will continue, so keep posted.