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0:00
Hello. My name is Peter Lipke
from the Biology Department
at Brooklyn College of the
City University of New York.
Today I'm going to
give a lecture on
the roles of functional
amyloids in biofilms.
I hope at the end
of the lecture,
you have learned something about
biofilms and something about
amyloids and the intimate
connection between them.
0:22
Both amyloids and biofilms
are aggregations.
Amyloids are well-structured
aggregates of proteins at
the molecular scale
and biofilms are
well-structured
aggregations of microbes
at the cellular scale,
therefore we are talking
about aggregations with
size scales from
nanometers to centimeters.
Biofilms are communities
of aggregated microbes
embedded in a matrix and
they form at interfaces.
They form between solid
and liquid interfaces,
between liquid and
air interfaces
and between host and pathogen.
Here we see a
picture of a biofilm
about 5 cm in diameter
from Bacillus subtilis,
that's the one that's
nicely stained pink.
Amyloids are structured
aggregates of
proteins and they usually
form insoluble fibers.
Here's a picture of
some amyloid fibers.
They are typically
10-50 nm in diameter.
It turns out that
these amyloids have essential
functions in biofilms.
They provide both structure
and physical strength,
and at the bottom here is a
picture of a fungal biofilm.
The cells are 2-25 μm in length
and this micrograph
is stained to
show the amyloid structures.
1:38
Biofilms are full of amyloids.
Here on the left is
a scanning electron
micrograph of
a biofilm of E. coli bacteria.
The thin fibers highlighted by
the arrowheads are
amyloid fibers.
On the right is a
biofilm from the fungus
Candida albicans that's
stained with thioflavin T,
so amyloid is the only thing
that stains and you see
these beautiful amyloid sheets
around each of the cells
in each of the hyphae.
