Transcript Kingdom Monera - University of Hawaii

Kingdom Monera
What are PROKARYOTES?
They are ancient life forms
known as bacteria
• No nucleus
• No chloroplasts
• No mitochondria
Two major clades of bacteria
Archaebacteria
Methanogens
Extreme Thermophiles
Extreme Halophiles
& Eubacteria
Cyanobacteria (Blue-green algae) & other
Gram negative bacteria
Gram positive bacteria
TEM of dividing cell
Prokaryotes Lack
Organelles
(w/ 2 membranes)
• No nucleus
but have DNA & RNA
• No chloroplasts
but have pigments,
thylakoids &
enzymes for PS
• No mitochondria
but have respiratory
chain & membranes
• Small ribosomes (70S)
for protein synthesis
Other constituents? Gas vacuoles;
Cell walls; Storage molecules for
N, P, C
Geoclock
Origin of life
Cyanophytes established
early aerobic environments.
Evolution of advanced aerobes
2 H2O + CO2 
“Primordial ANAEROBIC soup”
O2 + CH2O + H2O
More conventional geologic time table
MYA
ERA
2
65
Cenozoic
PERIOD
DOMINANT LIFE FORM
Quaternary
Age of angiosperms
Tertiary
150
Cretaceous
Rise of angiosperms
200
Jurassic
Age of cycads
Triassic
Rise of cycadophytes
300
Permian
Rise of conifers
350
Carboniferous
Age of lycopods, ferns, sphenopsids;
Rise of mosses
400
Devonian
Age of vascular plants; 1st seed plants
450
Silurian
1st vascular plants
500
Ordovician
Age of eukaryotic algae
600
Cambrian
Rise of eukaryotic algae and fungi
250
Mesozoic
4500 Precambrian
Rise of prokaryotes
Division Cyanophyta
Bacteria that are:
• Photosynthetic (convert
light energy to food)
• Produce O2 as a byproduct
of photosynthesis
• Some produce toxins
• Some have capacity to fix N2 into NH4
TEM of dividing cell
• Some have formed millions of years old
stromatolites as living structures
Cyanophytes have changed the path of evolution on earth
Things we will cover
General features - defining characteristics
Developmental lineages –
using morphology to understand evolution
Ecology – understanding roles in
interacting with other species
Commercial interests – exploit ecology
Evolution – diversity and change over time
General features
Ancient organisms but well
suited to earth’s habitats
2000 species, 150 genera
Habitats:
virtually everywhere
Oceans
Soil
Epiphytes
Freshwater
Hotsprings
Endophytes
Morphological Range:
Unicells to complex
multicell organisms
Cell Walls:
Gram negative bacteria
Trichodesmium blooms can cover
2x106 km2 and be seen via satellites
NASA
Diversity
Cell Walls
Being comprised
of only 20%
peptidoglycan,
the cell wall of
Gram-negative
bacteria is much
thinner than
Gram-positive
bacteria.
Gram-negative bacteria have two unique regions which surround the outer
plasma membrane: i) periplasmic space and ii) lipopolysaccharide layer.
• periplasmic space separates the outer plasma membrane from the peptidoglycan layer.
• lipopolysaccharide layer is adjacent to the exterior peptidoglycan layer
General features
Pigments -
photosynthesis
Storage
Products
• Chlorophyll a
• Phycobilins
Phycoerythrin
Phycocyanin
Allophycocyanin
Others
• Carotenoids
• UV absorbing molecules
Growth
Photosynthesis
& Pigments
sunlight
• Light energy is harvested
by the cell
• Only specific colors are absorbed
• Other colors are reflected
back to your eye
Chl a
Cell
thylakoids
Chl a
Phycobilins
Chlorophyll a
Tetrapyrrole Ring
Phytol Chain
Phycobilins
Open tetrapyrrole
phycoerythrin
phycocyanin
Photosynthesis
& Pigments
• Arrangement of light
harvesting structure is
specific and detailed
Chlorophyll a
General features
Pigments -
photosynthesis
• Chlorophyll a
• Phycobilins
Phycoerythrin
Storage
Products
• Starch (C)
• Cyanophycin (N)
• Poly Pi bodies
Phycocyanin
Allophycocyanin
Others
• Carotenoids
• UV absorbing molecules
Growth
Storage products
Starch
C = black
O = red
H = white
C = green
= blue
H = red
= white
P = purple
ATP
General features
What is in a typical cyanophyte cell?
DNA & RNA
Pigments, thylakoids
& enzymes for PS
Respiratory chain &
membranes
Small ribosomes (70S)
Cell walls ?
Storage molecules for
N, P, C ?
Floatation?
General features
Pigments -
photosynthesis
• Chlorophyll a
• Phycobilins
Phycoerythrin
Storage
Products
• Starch (C)
• Cyanophycin (N)
• Poly Pi bodies
Phycocyanin
Allophycocyanin
Others
Growth
• Every cell can 
• Multicellular
organisms:
Fragments regrow
“Spores” regrow
Akinetes germinate
• Branching
• Carotenoids
True branching
• UV absorbing molecules
False branching
Growth &
morphology
 1

1
Binary Fission
(cell division)
1

 1
1
Cell division for unicells:
2
 8

4
Produces genetically identical “offspring” or twins
Increases the numbers of cells in the population
by exponential growth, 2n
Divisions may be every 15 to 20 min
 16 cells

Growth &
morphology
Unicell populations grow rapidly
# cells in population
1200
Cyanotech ponds
900
Starting with 1 cell:
10 rounds of division
600
 1,000+ cells
300
0
1
3
5
7
Rounds of cell division
9
It’s not unusual
to have 10 6 to 108
cells / mL in
“blooms”
Developmental lineages
Evaluate adult form to gain insight in possible
evolutionary processes.
Step-by-step acquisition of new traits
via genetic change.
Examine reproductive cells and other characters
as additional data.
Useful means to construct evolutionary hypotheses
to test with molecular data.
Growth &
morphology
Developmental Lineage #1
Order Chroococcales
Genetic change
All cells appear virtually identical internally
Evolution has taken a simple shape
to more complex but related forms:
• Multicellular genera
Diversity
Order Chroococcales
Microcystis
Merismopedia
Growth &
morphology
1 colony
Coordinated
binary fission
of all cells in
colony
Multicellular organisms divide
but increase the number of
entities in the population


2 colonies
Growth &
morphology
Developmental Lineage #2
Order Chamaesiphonales
Evolution has taken a simple shape:
• attachment to the substrate
• spores released from upper end of cell
Growth &
morphology
Developmental Lineage #3
trichome + sheath Order Nostocales
(filament)
trichome
(no sheath
evident)
Evolution has taken a simple shape:
• constrained cells into chains
• formed arrays of trichome(s) in sheaths
• false branching can result
trichomes + sheath
Diversity
Order Nostocales
Growth &
morphology
False branching :
1. Rupture of sheath and cells
2. Remaining cells at both
ends continue to grow
3. Both trichomes push
through weakened sheath
What to look for?
Is there a change in the
plane of cell division?
Order Nostocales
New Cell Types
Order Nostocales
Nitrogen fixation supports
protein synthesis
1. Low N in environment
2. Cell differentiates as a
specialized cell, the heterocyst
3. Creates setting for
Nitrogenase enzyme
4. Enzyme converts N2  NH4+
polar heterocysts
Growth &
morphology
Order Nostocales
Nitrogen fixation & Azolla in
rice fields replace fertilizers
1. Low N in environment
2. Heterocysts differentiate
3. Enzyme converts N2  NH4+
4. Water fern benefits from fertilizer
5. Rice fields are more productive
intercalary heterocysts
Other cell types
Akinete
Anabaena
Order Nostocales
Cool stuff
Order Nostocales
Growth &
morphology
Developmental Lineage #4
Order Stigonematales
True branching
Evolution has taken a simple shape:
• formed arrays of cells that
divide in 2 directions (planes)
Multiseriate tissues
Growth &
morphology
True branching :
1. No rupture of sheath or cells
2. Cells divide in two planes
3. Create new structures,
branches
What to look for?
Is there a change in the
plane of cell division?
Order Stigonematales
Growth &
morphology
Complex tissue
• Multicellular
• Organized multiseriate layers
• Cell dimorphism
Order Stigonematales
Vocabulary
prokaryote
binary fission
thylakoid
phycobilins
phycobilisome
akinete
multiseriate
trichome
false branching
nitrogenase
eukaryote
nucleus
chloroplast
mitochondrion
accessory pigment
heterocyst
uniseriate
sheath
true branching
photosynthesis
Azolla
Anabaena
Lyngbya
Stigonema
Who am I?
Reading &
Viewing
Scientific American Extremophiles:
http://www.spaceref.com/redirect.html?id=0&url=www.sciam.com/0497issue/0497marrs.html
National Geographic:
http://www.nationalgeographic.com/world/0010/bacteria/bacteria.html
An underworld of hydrogen sulfide harbors life-forms awesome and awful:
http://www.nationalgeographic.com/ngm/0105/feature4/index.html
NASA interactive page
http://nai.arc.nasa.gov/_global/shockwave/g3_matgallery.swf
Powers of ten interactive page:
http://microscopy.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
Mereschowsky, C., (1905). Über Natur und Ursprung der Chromatophoren im Pflanzenreiche.,
Biol. Centr. 25, 593-604 & 689-691.
Mereschowsky, C., (1910). Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer
neuen Lehre von der Entstehung der Organismen., Biol. Centr. 30, 353-367, 1910.
Margulis, L. (1970). Origin of eukaryotic cells. Yale University Press, New Haven.
Picture credits
http://www.nhm.uio.no/palmus/galleri/montre/english/gruppe_liste_e.htm
http://astrobiology.arc.nasa.gov/roadmap/goals/index.html
http://www.lalanet.gr.jp/nsm/E-stromatolite.html
http://www.petrifiedseagardens.org/main.htm Saratoga Springs NY
http://www.rockhounds.com/grand_hikes/hikes/stromatolites_in_the_hakatai/
http://www.ngdc.noaa.gov/mgg/sepm/palaios/9810/knoll.html