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Cyanobacteria

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Cyanobacteria THE FIRST ALGAE!!!!! Asexual Reproduction Akinete thick walled resting spore Function resistant to unfavorable environmental conditions. – PowerPoint PPT presentation

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Title: Cyanobacteria


1
Cyanobacteria
  • THE FIRST ALGAE!!!!!

2
Evolution
  • Old 3.5 billion years
  • Dominated as biogenic reefs
  • During Proterozoic Age of Bacteria (2.5 bya
    750 mya) they were wide spread
  • Then multicellularity took over
  • Cyanobacteria were first algae!

3
Cyanobacteria terminology
  • - Division Cyanophyta
  • - Cyanobacteria formerly known as BlueGreen
    Algae
  • - Cyano blue
  • - Bacteria acknowledges that they are more
    closely related to prokaryotic bacteria than
    eukaryotic algae

4
Green Plants
Red Algae
Bacteria
Animalia
Archeae
Fungi
Other Eukaryotes
Prokaryotes
Eukaryotes
5
Cyanobacteria
Brown Algae
Green Plants
Red Algae
Diatoms
Archeae
Fungi
BOTANY
6
Cyanobacteria
  • Microscopic organisms
  • Found in marine sediments and pelagic zone,
    freshwater lakes, soils,
  • Live in extreme environments chemically and
    temperature.

7
Importance
!!!
  • 1) First organisms to have 2 photosystems and to
    produce organic material and give off O2 as a
    bi-product.
  • ?Very important to the evolution of the earths
    oxidizing atmosphere .

8
Importance
  • 2) Many fix or convert atmospheric nitrogen
    into usable forms through Nitrogen Fixation when
    other forms are unavailable.
  • IMPORTANT because atmospheric N2 is unavailable
    to most living organisms because breaking the
    triple bond is difficult

N
N
9
Cyanobacteria Characteristics
  • - Pigments chl a, phycobiliproteins
  • - phycoerythrin
  • - phycocyanin BlueGreen Color
  • - allophycocyanin
  • - Storage glycogen
  • - Cell Walls amino acids, sugars

10
Forms
  • Unicell with mucilaginous envelope
  • Colonies
  • Filaments uniserate in a single row
  • - OR - multiserate not TRUE branching when
    trichomes are gt 1 in rows

11
Features
  • Trichome row of cells

Filament
Mucilaginous sheath layer of mucilage outside
of the cell wall.
12
Features
  • Mucilaginous Sheath
  • Function protects cells from drying and
    involved in gliding.
  • Sheath is often colored
  • Red acidic
  • Blue basic
  • Yellow/Brown high salt

13
Features
  • Heterocyst thick walled cell, hollow looking.
    Larger than vegetative cells.
  • FUNCTION provides the anerobic environment for
    N fixation.

H- heterocyst
14
Heterocyst
Vegetative cells
Anabaena
15
Habit success due to ability tolerate a wide
range of conditions
  • Marine littoral and pelagic
  • Fresh Water
  • Hot Springs
  • Terrestrial soil flora

16
Heterocyst
  • Larger than vegetative cells
  • Hollow looking
  • Thick walled doesnt allow atmospheric gas to
    enter.
  • Photosynthetically inactive
  • No CO2 fixation or O2 evolution
  • Formation of heterocysts triggered by
    molybdenum and and low nitrogen

17
Nitrogen
  • Nitrogen is a limiting nutrient necessary for the
    production of amino acids building blocks of
    life.

18
Nitrogen Fixation
  • ONLY cyanobacteria and prokaryotic bacteria can
    FIX nitrogen.
  • Of these two only CYANOBACTERIA evolve OXYGEN
    during photosynthesis
  • Important because nitrogenase (enzyme involved in
    fixing nitrogen) is INACTIVATED by O2.

19
Mechanisms to Separate Nitrogenase from Oxygen
  • Heterocyst (spatial)
  • OR
  • Fix Nitrogen in the DARK but not LIGHT found in
    non-heterocystic cyanobacteria (temporal)

20
AEROBIC
LIGHT
  • CO2 H2O -----------? CH2O (sugar) O2
  • Electrons for PS1 come from PS2 which evolves
    oxygen (splitting of water)

21
ANAEROBIC in the presence of sulfer
  • 2H2S CO2 --------? CH2O 2S H2O
  • H2S is the electron donor so the reaction does
    not produce oxygen.

22
Advantage for Cyanobacteria
  • Can live in fluctuating environments of aerobic
    and anaerobic with light present.

23
Cyanotoxins in Cyanobacteria
  • Neurotoxins block neuron transmission in
    muscles (Anabaena, Oscillatoria)
  • Hepatotoxins inhibit protein phosphatase, cause
    liver bleeding. Found in drinking water.
    (Anabaena, Oscillatoria, Nostoc)
  • Eg. swimmers itch - Lygnbia

24
Movement
  • No flagellae or structures to enhance movement
  • Excrete mucilage jet propulsion, gliding
  • Helix fibers send waves of contraction

Spirulina
25
Spirulina
  • filamentous
  • common in lakes with high pH
  • major food for flamingo populations
  • commercial food source

26
  • Anabaena with a heterocyst
  • common bloom forming species with nutrient loads

27
Lyngbia martensiana
Releases chemicals causing dermatitis
28
Asexual Reproduction
  • - Hormogonia formation -
  • - Endospore / Akinete formation -
  • Fragmentation
  • Exospore

29
Asexual Reproduction
  • Hormogonia short piece of trichome found in
    filaments. It detaches from parent filament and
    glides away

Hormogonia
30
  • Oscillatoria with hormogonia
  • short pieces of a trichome that become detached
    from the parent filament and glide away to form
    new filament.

31
Oscillatoria (filamentous) with hormogonia
32
Asexual Reproduction
  • Akinete thick walled resting spore

33
Akinete
34
Asexual Reproduction
  • Akinete thick walled resting spore
  • Function resistant to unfavorable environmental
    conditions.
  • Appear as larger cells in the chain and different
    than heterocyst. Generally lose buoyancy

35
Asexual Reproduction
  • Fragmentation - fragmentation

36
Oldest Fossils
  • 3.5by old carbonaceous microfossils S.Africa
  • 3.4by old filaments and microbial fossils W.
    Australia
  • 3.4 by old stromatolites S.Africa, Australia

37
Cyanobacteria and Understanding the Past
Stromatolites Shark Bay, W. Australia
38
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