Phototrophic Bacteria
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Morphologies

The five major morphological types
among cyanobacteria are:
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–
–
–
–
Unicellular
Colonial
Filamentous
Filamentous heterocystous
Filamentous branching
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Unicellular


Gloeothece, phase
contrast; a single
cell measures 5-6
um in diameter.
(Brock6, 717)
Many cyanobacteria produce extensive
mucilaginous envelopes, or sheaths, that bind
cells or filaments together in aggregates.
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Colonial


Dermocarpa,
phase contrast
(Brock6, 717)
A colony, which contains millions of cells and
can be seen visually, develops from the asexual
reproduction of a single cell. A colony contains
a population of a single bacterial species.
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Filamentous

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Oscillatoria, bright field;
a single cell measures
about 15 um wide.
(Brock6, 717)
Marine Oscillatoria fix nitrogen without
heterocysts, and seem to produce of cells in the
centre of the filament that lack photosystem II
activity.
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Filamentous Heterocystous


Anabaena, phase;
single cell measures
about 5 um wide.
(Brock6, 717)
Some cyanobacteria form heterocysts, which
are rounded, seemingly empty cells, usually
distributed individually along a filament or at
one end of a filament.
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Filamentous Branching


Fischerella, bright field
(Brock6, 717)
Fischerella represents filamentous cyanobacteria
that divide in more than one plane to form
branches. These branching cyanobacteria also
form heterocysts and akinetes.
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Habitats
Nutrient rich rivers and lakes
 Hot Springs
 Mud flats
 Stagnant water
 Swamps - hydrogen sulfide

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Yankee Springs

Close up view of the
purple veils contains
several different species
of purple sulphur
bacteria. (Perry, pg. 518)
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
The darker green
growth that occurs on
the top in some areas is
due to cyanobacteria.
(Perry, pg. 518)
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Hot Spring

Grand Prismatic Spring (Yellowstone National Park)
shows the development of extensive mats of
photosynthetic bacteria (primarily cyanobacteria and
green bacteria).
The orange color at the
edge predominates
because of the rich
carotenoid pigments in
these organisms.
Brock4 pg 240
Plate 2
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Floating Cyanobacteria in
Lake


Floatation of cyanobacteria from a bloom on a
nutrient-rich lake, caused by the presence of gas
vesicles
Brock6 pg 78
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Bacterial mat

Close-up of a small bacterial mat, in Octopus
Spring, Yellowstone National Park. The
temperature where the mat shows the most
extensive development is about 55 degrees C.
Brock4 pg 240
Plate 2
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Chromatium
Micrograph of the purple sulfur
bacterium Chromatium species.
These bacteria deposit sulfur
granules within their cells that
are iridescent and appear
multicolored.
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Chromatium vinosum and okenii
Perry, 516
Prescott, 47

Chromatium vinosum, a purple
sulfur bacterium, with
intracellular sulfur granules,
light field (X2,000).
(Prescott, 47)
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
A phase photomicrograph
of Chromatium okenii. Note
the polar flagellum (a tuft)
as well as the internal
sulfur granules. The bar is
5 um. (Perry, 515)
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Chromatium and Thiocystis


Phase contrast
photomicrographs
of layers containing
purple sulfur
bacteria (large celled
Chromatium species
and Thiocystis)
brock6 pg 715
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“Chlorochromatium
aggregatum”

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Several
microcolonies of the
consortium species
“Chlorochromatium
aggregatum” are
shown by phase
microscopy in this
lake sample. (Perry,
pg. 524)
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
Thiospirillum
Thiospirillum from a
lake sample
showing sulphur
granules and polar
flagellar tuft. (Perry,
pg. 517)
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Cells are curved rod or
vibrioid-shaped, sigmoid or
spiral with rounded ends, 2.54.0 um in diameter.
Motile by means of a polar
flagellar tuft.
Anaerobic and phototrophic.
Found in mud and stagnant
water of ditches and
freshwater ponds containing
hydrogen sulphide.
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Thiodictyon

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Thiodictyon are rod
shaped bacteria
joined together at
their cell ends to
form a net. (Perry,
pg 517
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
Thiopedia
Cells of Thiopedia
grow in flat sheets.
Note the bright
appearance of the
gas vacuoles in each
cell. (Perry, pg. 517)
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Cells are spherical to ovoid or
elongated ovoid, 1.4-1.8 um
wide and 1.5-2.5 um long.
Anaerobic and phototrophic.
Inhabit the mud and stagnant
water of ponds and lakes
containing hydrogen
sulphide.
The optimum pH and growth
temperature is 7.3 and 20
degrees C respectively.
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Pelodictyon

Cells of Pelodictyon
clathratiforme showing
net formation in small
individual cells with gas
vacuoles. (Perry, pg.
523)
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
Pelodictyon phaeum
showing brownish
color of cells in net.
(Perry, pg. 523)
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Prochloron

Prochloron. Each cell in
a cluster contains
chlorophyll arranged
on membranous layers.
(Black2, pg 261)

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Colorized electron micrograph of the
photosynthetic bacterium Prochloron
didemni reveals that it has extensive
internal membranes that have
photosynthetic pigments (green).
Magnification 6400X. (Atlas, pg 145)
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Thiocapsa

Thiocapsa roseopersicina.
Bar = 10 um.
(Prescott, pg. 466)
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
Tubular type from
Thiocapsa pfennigii
(Perry, 516).
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Pelodictyon clathratiforme

Typical green sulfur
bacteria- Pelodictyon
clathratiforme.
(Prescott, pg. 469)

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Brock4 pg 637 Pelodictyon
clathratiforme, a bacterium
forming a three dimensional
network. Magnification
1700X.
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Rhodospirillum molischianum

Lamellar type from
Rhodospirillum molischianum
(Perry, 516)
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Rhodospirillum rubrum

Rhodospirillum rubrum
in phase-contrast light
microscope (600X)
(Prescott, pg. 31)
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
R. rubrum in transmission
electron microscope (X100,000)
(Prescott, pg. 31)
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Rhodocyclus purpureus

Rhodocyclus purpureus,
phase contrast. Bar = 10
um. (Prescott, pg. 468)
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Rhodopseudomonas


Rhodopseudomonas
acidophila, phase contrast.
(Prescott, pg. 468)
Transmission electron
micrograph of thin section
of dividing cells of
Rhodopseudomonas marina.
Cells are 0.7 um in
diameter. (Brock6, pg. 44)
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Rhodomicrobium vannielii
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Rhodomicrobium
vannielii with
vegetative cells and
buds, phase
contrast. (Prescott,
pg. 468)
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Spiral-shaped

Rhodospirillum rubrum, an
anoxygenic photosynthetic
bacterium. (Black2, pg. 260)
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Gas Vesicles
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Electron micrographs of gas vesicles purified from the
bacteria Microcyclus aquaticus and examined in
negatively stained preparations
A single gas vesicle is about 100 nm in diameter.
Brock6
pg 78
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Gloeocapsa

Unicellular colonial, Gloeocapsa sp.
Magnification 1500X pg 645 brock4
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
Heterocytst
Filamentous chains of cells of
a cyanobacterium in the
genus Anabaena. The
distinctive ellipsoidal cells
are called heterocysts and are
the sites where the process of
nitrogen fixation is carried
out. (VanDemark, pg 40)
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Micrograph of the
cyanobacterium Anabaena
cylindrica, showing
vegetative cells and a
heterocyst (enlarged cell)
in which nitrogen fixation
occurs. (Atlas, pg. 49)
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

Brock4 pg 637
Electron micrograph of Oscillochloris. The
chromosomes in this preparation are darkly
stained. Magnification 14800X.
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Oscillatoria
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Chlorobium limicola
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Green bacterium:
Chlorobium limicola.
The refractile bodies are
sulfur granules
deposited outside the
cell.
(Brock6 pg 570)
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Thiopedia roseopersicinia

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Massive accumulation of
purple sulfur bacteria,
Thiopedia roseopersicinia,
in a spring in
Madison,Wisconsin. The
bacteria grow near the
bottom of the spring
pool and float to the top
(by virtue of their gas
vesicles) when
disturbed. (Brock6, pg.
716)
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
A rosette of
Thiothrix from
a sulfur spring.
(Perry, pg. 543)
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Thiothrix

Phase photomicrograph of a
sulfur bacterium
Tiothrix nivea.
(Perry, 87)
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Gloeothece

Phase photograph of
a Gloeothece sp.
showing the cells
within the sheath.
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Prochlorothrix

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Scanning electron
micrograph of
Prochlorothrix, a marine
prochlorophyte. Bar is 3
um.
(Perry,
pg. 532)
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DONE!!!
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Endospores
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Light photomicrographs illustrating several types of endospore
morphologies and intracellular locations
(A) Central endospore
(B) Subterminal endospore
(C) Terminal endospore
Brock6 pg 79
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Endospore
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