General Microbiology – Full course notes
Lecture 1: Historical and Current Aspects of Microbiology
Learning
Objectives
Be
able:
• To
define
Microbiology
• To
differentiate
the
major
characteristics
for
each
type
of
microorganism
in
the
microbial
world
• To
identify
the
contributions
to
microbiology
&
germ
theory
made
by
past
microbiologists
• To
appreciate
the
genomic
revolution
occurring
in
Microbiology
What
is
Microbiology?
-‐ Microbiology
is
the
study
of
organisms
too
small
to
be
seen
with
the
naked
eye
-‐ Eukaryotes:
have
a
membrane
bound
nucleus,
more
complex
and
larger
than
pro
-‐ Prokaryotes:
Lack
a
membrane
bound
nucleus
-‐ Single
cells
that
can
grow
independently
and
do
not
rely
on
other
cells
to
live
-‐ Might
exist
in
a
multi-‐cellular
community
e.g.
grime
in
toilet
The
Microbial
World
Cellular
–
can
replicate
on
their
own,
acellular
cannot.
History
of
Microbiology
-‐ Stelluti,
Hooke,
Van
Leeuwenhoek,
first
people
to
observe
and
describe
microorganisms
-‐ Spontaneous
Generation:
Living
organisms
could
develop
from
non-‐living
matter
-‐ Louis
Pasteur:
disproving
the
theory
of
spontaneous
generation
Germ
Theory
-‐ Infectious
disease
was
thought
to
be
caused
by
supernatural
forces
-‐ Support
for
germ
theory
came
from
a
number
of
studies
o Agostini
Bassii
(1773-‐1856)
–
fungi
on
silk
worms
o M.J
Berkeley
(1803-‐1889)
–
potato
blight
caused
by
fungi
o Joseph
Lister
(1827-‐1912)
–
sterilizing
equipment
reduced
infection
Koch’s
Postulates
-‐ Suspected
pathogen
must
be
present
in
all
cases
of
disease
and
absent
in
healthy
-‐ Pathogen
must
be
grown
in
pure
culture
-‐ Cells
from
pure
culture
must
cause
disease
in
healthy
animal
-‐ Suspected
pathogen
must
be
reinsulated
and
shown
to
be
same
as
the
original
(rod
and
rod
etc.)
N.B.
there
are
some
cases
where
we
cannot
use
Koch’s
postulates
Size
,
DNA/RNA
<
VIRUSES
<
BACTERIAS
<
EUKARYOTIC
CELLS
<
SMALL
ORGANISMS
Microbiology
Tools
-‐ Light
Microscope
can
allow
you
to
see
microscopic
but
not
small
as
viruses
-‐ Culturing:
agar
plates,
liquid
mediums
etc.
-‐ DNA
sequencing:
sequencing
genes,
genomes,
comparing,
identifying
virulence
or
other
genes.
Pure
culture
à
Genome
à
Ask
questions.
Meta-‐genome
=
from
a
number
of
cells
e.g.
soil,
sample
from
gut
etc.
allows
to
see
what
genes
define
this
environment
Microbial
Diversity
Learning
objectives:
-‐ To
recognize
microbial
diversity
at
multiple
levels
-‐ To
identify
different
ways
for
describing
diversity
in
microbes
Diversity
of
Microorganisms
Diversity:
The
range
of
features
of
degree
of
difference
between
organisms
in
a
particular
environment.
Three
types
of
microbial
diversity:
1. Physical/structural
e.g.
cell
shapes,
gram
stain
2. Biochemical/metabolic
e.g.
energy
sources,
secondary
metabolites
3. Genome
i.e.
DNA
sequence
1. Diversity
of
Morphology
–
Prokaryotes
Cocci
(Spheres)
–
1
um
diameter
Arrangements:
-‐ Diplococci:
pairs
-‐ Chains
(e.g.
streptococci)
-‐ Clusters
(e.g.
Staphylococci)
-‐ Tetrads
(4
cocci
in
a
square)
-‐ Sarcinia
(8
cocci
in
a
cube)
Bacilli
–
Rods
–
1um
x
3um
-‐ Coccobacilli
(very
short
rods)
-‐ Filamentous
(long
rods)
-‐ Vibrios
(curved
rods)
-‐ Blunt
or
Square
ends
Arrangements:
cells
arranged
singly,
in
short
chains,
palisade
or
Chinese
Lettering
Less
Common:
-‐ Spirilla
-‐
rigid
helices
-‐ Spirochetes
-‐
flexible
helices
(usually
quite
long,
internalized
flagella)
-‐ Coryneform
-‐
variable
appearance
(usually
rod-‐like)
-‐ Pleomorphic
-‐
variable,
irregular
shapes,
occasionally
branched
-‐ Flattened
rectangles,
triangles
&
trapezoids
(rare)
1. Diversity
of
Morphology
–
Eukaryotes
-‐ Morphologically
more
complex
than
prokaryotes
-‐ Protists
(diverse
taxa)
-‐ Fungi
(one
taxon)
1. Diversity
of
Morphology
–
Viruses
Lecture 1: Historical and Current Aspects of Microbiology
Learning
Objectives
Be
able:
• To
define
Microbiology
• To
differentiate
the
major
characteristics
for
each
type
of
microorganism
in
the
microbial
world
• To
identify
the
contributions
to
microbiology
&
germ
theory
made
by
past
microbiologists
• To
appreciate
the
genomic
revolution
occurring
in
Microbiology
What
is
Microbiology?
-‐ Microbiology
is
the
study
of
organisms
too
small
to
be
seen
with
the
naked
eye
-‐ Eukaryotes:
have
a
membrane
bound
nucleus,
more
complex
and
larger
than
pro
-‐ Prokaryotes:
Lack
a
membrane
bound
nucleus
-‐ Single
cells
that
can
grow
independently
and
do
not
rely
on
other
cells
to
live
-‐ Might
exist
in
a
multi-‐cellular
community
e.g.
grime
in
toilet
The
Microbial
World
Cellular
–
can
replicate
on
their
own,
acellular
cannot.
History
of
Microbiology
-‐ Stelluti,
Hooke,
Van
Leeuwenhoek,
first
people
to
observe
and
describe
microorganisms
-‐ Spontaneous
Generation:
Living
organisms
could
develop
from
non-‐living
matter
-‐ Louis
Pasteur:
disproving
the
theory
of
spontaneous
generation
Germ
Theory
-‐ Infectious
disease
was
thought
to
be
caused
by
supernatural
forces
-‐ Support
for
germ
theory
came
from
a
number
of
studies
o Agostini
Bassii
(1773-‐1856)
–
fungi
on
silk
worms
o M.J
Berkeley
(1803-‐1889)
–
potato
blight
caused
by
fungi
o Joseph
Lister
(1827-‐1912)
–
sterilizing
equipment
reduced
infection
Koch’s
Postulates
-‐ Suspected
pathogen
must
be
present
in
all
cases
of
disease
and
absent
in
healthy
-‐ Pathogen
must
be
grown
in
pure
culture
-‐ Cells
from
pure
culture
must
cause
disease
in
healthy
animal
-‐ Suspected
pathogen
must
be
reinsulated
and
shown
to
be
same
as
the
original
(rod
and
rod
etc.)
N.B.
there
are
some
cases
where
we
cannot
use
Koch’s
postulates
Size
,
DNA/RNA
<
VIRUSES
<
BACTERIAS
<
EUKARYOTIC
CELLS
<
SMALL
ORGANISMS
Microbiology
Tools
-‐ Light
Microscope
can
allow
you
to
see
microscopic
but
not
small
as
viruses
-‐ Culturing:
agar
plates,
liquid
mediums
etc.
-‐ DNA
sequencing:
sequencing
genes,
genomes,
comparing,
identifying
virulence
or
other
genes.
Pure
culture
à
Genome
à
Ask
questions.
Meta-‐genome
=
from
a
number
of
cells
e.g.
soil,
sample
from
gut
etc.
allows
to
see
what
genes
define
this
environment
Microbial
Diversity
Learning
objectives:
-‐ To
recognize
microbial
diversity
at
multiple
levels
-‐ To
identify
different
ways
for
describing
diversity
in
microbes
Diversity
of
Microorganisms
Diversity:
The
range
of
features
of
degree
of
difference
between
organisms
in
a
particular
environment.
Three
types
of
microbial
diversity:
1. Physical/structural
e.g.
cell
shapes,
gram
stain
2. Biochemical/metabolic
e.g.
energy
sources,
secondary
metabolites
3. Genome
i.e.
DNA
sequence
1. Diversity
of
Morphology
–
Prokaryotes
Cocci
(Spheres)
–
1
um
diameter
Arrangements:
-‐ Diplococci:
pairs
-‐ Chains
(e.g.
streptococci)
-‐ Clusters
(e.g.
Staphylococci)
-‐ Tetrads
(4
cocci
in
a
square)
-‐ Sarcinia
(8
cocci
in
a
cube)
Bacilli
–
Rods
–
1um
x
3um
-‐ Coccobacilli
(very
short
rods)
-‐ Filamentous
(long
rods)
-‐ Vibrios
(curved
rods)
-‐ Blunt
or
Square
ends
Arrangements:
cells
arranged
singly,
in
short
chains,
palisade
or
Chinese
Lettering
Less
Common:
-‐ Spirilla
-‐
rigid
helices
-‐ Spirochetes
-‐
flexible
helices
(usually
quite
long,
internalized
flagella)
-‐ Coryneform
-‐
variable
appearance
(usually
rod-‐like)
-‐ Pleomorphic
-‐
variable,
irregular
shapes,
occasionally
branched
-‐ Flattened
rectangles,
triangles
&
trapezoids
(rare)
1. Diversity
of
Morphology
–
Eukaryotes
-‐ Morphologically
more
complex
than
prokaryotes
-‐ Protists
(diverse
taxa)
-‐ Fungi
(one
taxon)
1. Diversity
of
Morphology
–
Viruses
