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Mks cyanobacteria
 

Mks cyanobacteria

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Cyanobacteria are photosynthetic group of bacteria that can fix atmospheric nitrogen essential for aminoacid biosynthesis. Earlier they were called as blue green algae. Now that name is not used ...

Cyanobacteria are photosynthetic group of bacteria that can fix atmospheric nitrogen essential for aminoacid biosynthesis. Earlier they were called as blue green algae. Now that name is not used because they are not belongs to the algae.

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    Mks cyanobacteria Mks cyanobacteria Presentation Transcript

    • Cyano bacteria Dr. M.K. SATEESH Molecular Diagnostics Laboratory Department of Microbiology and Biotechnology Bangalore University, Jnana Bharathi campus Bangalore-560 056 Microcystis Gleocapsa Nostoc Anabaena Scytonema Spirulina
    • 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 Billion Years Before Present Earth formed Precambrian Time: The Time of Prokaryotes Phanerozoic Time Eukaryotic Time Archaean Era: Era of Archaea Proterozoic Era: Era of Cyanobacteria First Life First Cyanobacteria O 2 First Eukaryotes Timeline of Planet Earth
    • 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!
    • Cyanobacteria terminology - Division Cyanophyta - Cyanobacteria ‘formerly known as’ Blue Green Algae - Cyano = blue - Bacteria – acknowledges that they are more closely related to prokaryotic bacteria than eukaryotic algae
    • Bacteria Archeae Other Eukaryotes Animalia Fungi Green Plants Red Algae Prokaryotes Eukaryotes
    • Cyanobacteria Archeae Brown Algae Fungi Green Plants Red Algae BOTANY Diatoms
    • Cyanobacteria
      • Microscopic organisms
      • Found in marine sediments and pelagic zone, freshwater lakes, soils,
      • Live in extreme environments – chemically and temperature.
    • Importance
      • 1) First organisms to have 2 photosystems and to produce organic material and give off O 2 as a bi-product.
      •  Very important to the evolution of the earths’ oxidizing atmosphere .
      !!!
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    • Cyanobacteria Members
    • Importance
      • 2) Many – fix or convert atmospheric nitrogen into usable forms through Nitrogen Fixation when other forms are unavailable.
      • IMPORTANT because atmospheric N 2 is unavailable to most living organisms because breaking the triple bond is difficult
      N N
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    • Cyanobacteria Characteristics - Pigments – chl a, phycobiliproteins - phycoerythrin - phycocyanin * Blue Green Color - allophycocyanin - Storage – glycogen - Cell Walls – amino acids, sugars
    • Forms
      • Unicell – with mucilaginous envelope
      • Colonies –
      • Filaments – uniserate in a single row
      • - OR - multiserate – not TRUE branching when trichomes are > 1 in rows
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    • http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg Cyanobacterial Vegetative Cell (photosynthesis) cell wall cell membrane lipid droplet nucleoid polyhedral body cyanophycin thylakoids cyanophycean starch vacuole polyphosphate granule Division by Binary Fission and Cytokinesis by Furrowing
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    • Features Trichome – row of cells Mucilaginous sheath – layer of mucilage outside of the cell wall. } Filament
    • Features Mucilaginous Sheath – Function – protects cells from drying and involved in gliding. Sheath is often colored: Red = acidic Blue = basic Yellow/Brown = high salt
    • Features Heterocyst – thick walled cell, hollow looking. Larger than vegetative cells. FUNCTION – provides the anerobic environment for N fixation. H- heterocyst
    • Anabaena Heterocyst Vegetative cells
    • Habit – success due to ability tolerate a wide range of conditions
      • Marine – littoral and pelagic
      • Fresh Water
      • Hot Springs
      • Terrestrial – soil flora
    • Heterocyst (N 2 fixation) Akinete (hypnospore) Anabaena --a cyanobacterium w/ division of labor Vegetative Cells (Photosynthesis)
    • http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/Heterocyst.jpg Cyanobacterial Heterocyst (N 2 fixation) cell wall cell membrane nucleoid pore in wall Intracellular thylakoids ETS for O 2 reduction fuel input for respiration O 2 block cytosol Nitrogenase reduces N 2 (requires anaerobic conditions)
    • Heterocyst
      • Larger than vegetative cells
      • Hollow looking
      • Thick walled – doesn’t allow atmospheric gas to enter.
      • Photosynthetically inactive
      • No CO 2 fixation or O 2 evolution
      • Formation of heterocysts triggered by [molybdenum] and and low [nitrogen]
    • Nitrogen
      • Nitrogen is a limiting nutrient necessary for the production of amino acids = building blocks of life.
    • 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 O 2 .
    • Mechanisms to Separate Nitrogenase from Oxygen
      • Heterocyst (spatial)
      • OR
      • Fix Nitrogen in the DARK but not LIGHT – found in non-heterocystic cyanobacteria (temporal)
    • AEROBIC
      • CO 2 + H 2 O -----------  CH 2 O (sugar) +O 2
      • Electrons for PS1 come from PS2 which evolves oxygen (splitting of water)
      LIGHT
    • ANAEROBIC in the presence of sulfer
      • 2H 2 S + CO 2 --------  CH 2 O +2S + H 2 O
      • H 2 S is the electron donor – so the reaction does not produce oxygen.
    • Advantage for Cyanobacteria
      • Can live in fluctuating environments of aerobic and anaerobic with light present.
      • Cyanobacteria can fix gaseous nitrogen, and are efficient at storing phosphorus. Buoyancy of this species varies due to the changing size of their internal pockets of gas. These alga cells can migrate in calm waters in response to nutrient or light gradients. Akinetes are capable of living in sediments for months and even years and then “seed” a water body. Optimal conditions for cyanobacteria growth are high temperature long sunny days, high levels of phosphorus and nitrogen, and calm winds which allow the cells to migrate to the surface. Reproduction takes place through trichome fragmentation, the splitting of the chain of cells, and is promoted by photosynthesis.
    • 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
    • Movement
      • No flagellae or structures to enhance movement
      • Excrete mucilage – jet propulsion, gliding
      • Helix – fibers send waves of contraction
      • Cyanobacteria can spread naturally through connected waterways, but humans can also contribute to its dispersal. Through movement from one water body to another, humans can carry blue-green algae with them on trailers, boats and in bait buckets thus aiding in its spread.
      Spirulina
    • Spirulina
      • filamentous
      • common in lakes with high pH
      • major food for flamingo populations
      • commercial food source
      • Anabaena with a heterocyst
      • common bloom forming species with nutrient loads
    • Lyngbia martensiana Releases chemicals causing dermatitis
    • Asexual Reproduction
      • Binary Fission
      • Hormogonia formation
      • Akinete formation
      • Fragmentation
      • Endospore
      • Exospore
    • Cyanobacterial fission Gloeocapsa sp., algae. (Light micrograph of Gloeocapsa sp., a type of blue-green algae or cyanobacteria. They reproduce solely by fission, a form of asexual division in which two identical algae are produced. Binary fission of cyanobacteria Binary fission
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    • Asexual Reproduction
      • Hormogonia – short piece of trichome found in filaments. It detaches from parent filament and glides away
      Hormogonia
      • Oscillatoria with hormogonia
      • short pieces of a trichome that become detached from the parent filament and glide away to form new filament.
    • Oscillatoria (filamentous) with hormogonia
    • Asexual Reproduction
      • Akinete – thick walled resting spore
      A - akinete H
    • 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
      A - akinete H
    • Akinete
    • Cyanobacterial Akinete (hypnospore) cell wall cell membrane lipid droplet nucleoid polyhedral body cyanophycin thylakoids cyanophycean starch vacuole polyphosphate granule
    • Germinating akinetes (producing vegetative filaments)
    • Asexual Reproduction
      • Fragmentation - fragmentation
    • Spores: endospores, exospores and nanocysts
    • 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
    • Cyanobacterial blooms Microcystis bloom in Matilda Bay, Swan-Canning Estuary, Western Australia.
    • Cylindrospermum Calothrix Chroococcus I. K. International Pvt Ltd, 2009 Nostoc commune
    • Schematic summary figure of the cyanobacteria life cycle (prototype for species of the order Nostocales). Vegetative cells grow only until nitrogen depletion forces them to build heterocysts, thus enabling the cells to grow further by nitrogen fixation. At the end of summer vanishing light prevents further growth; some of the cells differentiate into akinetes, the resting spores which sink to the bottom where they take up nutrients and mature during winter and spring. Finally, if the conditions are sufficiently favourable the cells germinate and begin to rise to the surface with the help of gas vacuoles. Here, light is abundant and growth of vegetative cells takes place, starting the life cycle again.
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    • Gleocapsa Microcystis Scytonema Spirulina Disruption of gas vesicles of Microcystis by plasma in water.
    • Microcystis aeruginosa is a unicellular, planktonic freshwater cyanobacterium. The existence of intracellular structures, the gas vesicles, provides cells with buoyancy. These hollow, gas-filled structures can keep Microcystis cells close to the surface of water body, where there is optimal light and oxygen for growth. Thus, when the water column is stable, the colonies can accumulate at the water surface and form surface water blooms. Cells range from 2.61 to 5.40μm in diameter, and can be either ovoid or spherical in shape. The extracellular covering of cell was divided into several layers: the cytoplasmic membrane or plasmalemma, the peptidoglycan layer, and the multilayered structure of the cell wall. Microcystis is light dependent and oxygenic, but cells may live under the dark anaerobic conditions for periods of time in eutrophic lakes. Microcystis aeruginosa often form blooms in eutrophic lakes and reservoirs. Surface water blooms can cause anaerobic conditions below the surface in the water and thus make other phytoplankton including M. aeruginosa themselves live in an unfavorable environment. However, M. aeruginosa appeared to be more tolerant to dark anaerobic conditions, which may be important to the dominance of M. aeruginosa in eutrophic lakes.
    • Gloeocapsa may be unicellular or made up of small groups of cells grouped within concentric mucilage envelopes. The individual colonies are usually spherical, microscopic, and enclosed within larger masses of mucilage. The cells are oval-shaped or ellipsoidal, and hemispherical after dividing. Each cell has a rounded, firm, inner mucilaginous sheath surrounded by older sheath material from the parent cell, revealing the pattern of cell division. The sheaths are colorless or vivid shades of yellow, brown, red, orange, blue, or violet, and may be affected by changes in pH. The cells are usually bright blue-green or olive green and do not have distinct gas vesicles. Inner mucilage sheaths surrounds each cell or recently divided pairs of cells, as indicated. Staining the specimens with India Ink makes the mucilage clearly visible against the dark background. From Greek gloia , "glue" + Latin capsa , "box"
    • Spirulina are Gram-negative, with soft cell walls that consist of complex sugars and protien. They are undifferentiated and filamentous. Spirulina can be rod- or disk-shaped. Their main photosynthetic pigment is phycocyanin, which is blue in color. These bacteria also contain chlorophyll a and carotenoids. Some contain the pigment phycoythrin, giving the bacteria a red or pink color. Spirulina also have gas vesicles, giving them bouyancy in the aquatic environments they inhabit. Spirulina are photosynthetic, and therefore autotrophic. Spirulina reproduce by binary fission.
    • Nostoc is a diverse genus of cyanobacteria. They are found in gelatinous colonies, composed of filaments called "trichomes" surrounded by a thin sheath. They are common in both aquatic and terrestrial habitats. These organisms are known for their unusual ability to lie dormant for long periods of time and abruptly recover metabolic activity when rehydrated with liquid water. The bacteria's ability to withstand freezing and thawing cycles make them well-adapted to living in extreme environments, such as the Arctic and Antarctica. They can fix atmospheric nitrogen, making them good candidates for environments with low nitrogen rates. Nostoc , first discovered in the 19th century, is one of the most widespread phototrophic bacteria in the world. As a nitrogen fixer, these bacteria may provide plants with important nutrients and therefore can be used agriculturally. In 1988 a terrestrial species, Nostoc commune , was found to harbor a previously unidentified UV-A/B absorbing pigment. This protective pigment has enabled them to survive not only while under hydration-related stress, but in areas of extreme UV radiation as well.
    • Anabaena Nostoc
    • Anabaena are heterocyst-forming, photoautotrophic cyanobacteria that perform oxygenic photosynthesis. Anabaena grow in long filaments of vegetative cells. During times of low environmental nitrogen, about one cell out of every ten will differentiate into a heterocyst. Heterocysts then supply neighboring cells with fixed nitrogen in return for the products of photosynthesis, that they can no longer perform. This separation of functions is essential because the nitrogen fixing enzyme in heterocysts, nitrogenase, is unstable in the presence of oxygen. Due to the necessity of keeping nitrogenase isolated from oxygen, heterocysts have developed elements to maintain a low level of oxygen within the cell. To prevent the entrance of oxygen into the cell, the developing heterocyst builds three additional layers outside the cell wall, giving it its characteristic enlarged and rounded appearance, thus the rate of oxygen diffusion into heterocysts is 100 times lower than of vegetative cells. One layer creates an envelope polysaccharide layer where the nitrogen is fixed in a oxygen-restricted milieu. To lower the amount of oxygen within the cell, the presence of photosystem II is eliminated, and the rate of respiration is stepped up to use up excess oxygen.
    • Scytonema is a filamentous aquatic bacterium and can be found in fresh water environments. S. crispum is important ecologically because it has the ability to fix nitrogen from the environment. Because of this, scytonema can also form symbiotic relationships with other organisms such as fungi. The genus Scytonema is especially important because these bacterium have been found to produce special chemicals such as toxins. In 2003 an anti-HIV protein, scytovirin, was isolated from a bacterial species of Scytonema . Scytonema reproduce by hormogonia, which develop at the ends of branches and bud from sheaths. Hormogonia germinate at both ends and form isopolar filaments. Scytonema crispum fixes nitrogen, thus providing nitrogen to the leaves of plants on which it is growing. This allows for some symbiotic relationships to be established with other organisms. Within scytonema's filamentous cells are heterocysts which are structures without oxygen that allow the enzyme nitrogenase to fix atmospheric nitrogen into ammonium.
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    • National Institute for Environmental Studies. Class GENUS SPECIES NO. STRAIN NO. Cyanophyceae Acaryochloris   1  1  Cyanophyceae Anabaena   28  183  Cyanophyceae Anabaenopsis   1  3  Cyanophyceae Anacystis   1  1  Cyanophyceae Aphanizomenon   1  5  Cyanophyceae Aphanocapsa   1  1  Cyanophyceae Aulosira   1  1  Cyanophyceae Calothrix   6  10  Cyanophyceae Chamaesiphon   2  2  Cyanophyceae Chroogloeocystis   1  1  Cyanophyceae Cylindrospermopsis   1  11  Cyanophyceae Cylindrospermum   1  1  Cyanophyceae Fischerella   1  1  Cyanophyceae Gloeocapsa   1  1  Cyanophyceae Hydrococcus   1  1  Cyanophyceae Leptolyngbya   1  3  Cyanophyceae Limnothrix   1  1  Cyanophyceae Merismopedia   1  1  Cyanophyceae Microcystis   1  333  Cyanophyceae Myxosarcina   1  1  Cyanophyceae Nostoc   5  14  Cyanophyceae Oscillatoria   8  10  Cyanophyceae Phormidium   9  19  Cyanophyceae Planktothricoides   1  2  Cyanophyceae Planktothrix   2  15  Cyanophyceae Plectonema   2  2  Cyanophyceae Prochlorococcus   1  2  Cyanophyceae Pseudanabaena   1  2  Cyanophyceae Raphidiopsis   1  2  Cyanophyceae Scytonema   1  2  Cyanophyceae Spirulina   2  7  Cyanophyceae Stigonema   1  1  Cyanophyceae Symploca   1  1  Cyanophyceae Synechococcus   1  57  Cyanophyceae Thermosynechococcus   2  2  Cyanophyceae Tolypothrix   2  3  Cyanophyceae Tychonema   1 
    • Stromatolites – Shark Bay, W. Australia Cyanobacteria and Understanding the Past