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Cyanobacteria ppt recent

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Cyanobacteria
Cyanobacteria
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Cyanobacteria ppt recent

  1. 1. CYANOBACTERIA Mrinalini Devi .U.G
  2. 2. Classification Domain-Bacteria Kingdom –Monera Division-Eubacteria Class-Cyanobacteria
  3. 3. Cyanobacteria cyanobacteria previously know as blue-green algae group of photoautotrophic ,gram negative bacteria get their name cyanobactria (cyan-blue due to the blue pigment phycocynin present along with chlorophyll-a Some red or pink pigment called phycoerythrin Evolved 3.5 billion years ago Includes 150 genera and 2,798 sps
  4. 4. Alglal bloom in red sea(Tricodesmium erythraeum)
  5. 5. HABITAT  Microscopic forms occur ubiquitously in nature  mostly aquatic,occurring in fresh , brakish and marine water.  Some form symbiotic associations with higher plants,bryophytes ,lichens and protists  They occur as planktonic forms or as benthic forms  some form phototrophic biofilms  They occur on moist trunks , moist soils and in extreme conditions like hot springs ‘ frozen lakes and salt water
  6. 6.  Though not related to algae(eukaryotic) they were earlier classified under algae  Later found that it has more characteristics similar to bacteria . Some of them fix atmospheric nitrogen eg. nostoc , Anabena
  7. 7.  Morphology of cyanobacteria  Unicellular , colonial or filamentous .  Each filament covered in sheath of mucilage in which cellular strands  called trichomes  Flagella absent but some show gliding movement
  8. 8.  Ultra structure of Cell
  9. 9. Cell structure  Cyanobacterial cells range in size from 0.5-1 μm to 40 μm in diameter  Cells larger than bacteria more elaborate than  Prokaryotic in nature  Presence of mucilagenous sheath, a characteristic feature outside cell wall  Cell Wall; four layered .peptidoglycan is second layer  Outer layer of protoplast has photosynthetic thylakoids  It is called chromoplasm  Thylakoids freely found  Their membranes contain chlorophyll a , carotenes and xanthophylls  Attached to outer layer- phycobillosomes
  10. 10.  Plasma membrane present below cell wall  Made of protein-lipid layer  Cytoplasm divided into outer pigmented region –chromoplasm  inner colourless central region called centroplasm  Chromoplasm –has flattened vesicles called thylakoids containing pigments such as  Chlorophyll,carotenoids and phycobillins(phycocyanin,phycoerythrin and alloerythrin)
  11. 11.  Centoplasm has a nucleoid or incipient nucleus  Segmented circular DNA ,small circular DNA present,70S ribosome  Food storage-cynophycean starch  (alpha granules)  Protein granules and lipid granules  Presence gas vacuoles also called pseudo-vacuoles  Help in buoyancy
  12. 12.  Presence of specialised cells - HETEROCYST  Pale yellow,Thick-walled,nodules,larger than other vegetative cells with homogenenous content intercalary in position  specialized cells help in nitrogen fixation contain nitrogenase enzyme
  13. 13. Akinetes thick-walled ,enveloped, non-motile , dormant cell Contain food reserve produced to tide over unfavourable condition Over unfavourable condition
  14. 14. ,  GAIDUKOV PHENOMENON OR COMPLEMENTARY CHROMATIN ADAPTATION  The efficiency to change pigment composition to absorb maximum light for photosynthesis,with variation of incident light-Gaidukov phenomenon  cyanobacteria have the capacity to change colour in relation to wavelength of incident light
  15. 15. Reproduction Vegetative and asexual methods 1) vegetative Fragmentation At regular intervals filaments get cut for short pieces of 5-15 cells called hormogonia Show gliding movement Later develop into full fledged filaments filament
  16. 16.  Asexual reproduction 1. Binary or multiple fission 2. hormospores 3. Spore formation a)Akinetes b)endospores c)exospores Binary repoduction simple type of cell division.First genetic genetic material separate moves to to opposite pole.A ring-like ougowth appears in the middle and divide into two
  17. 17.  Hormospores under unfavourable conditions some cells develop thick wall such cells called harmospores germinate in favourable conditions
  18. 18.  Spore formation  Akinetes or arthospores thick-walled,enveloped reproductive structures 1. Store reserve food material 2. Yellow-brown in colour 3. Germinate in favourable condition Endospores Some cyanobacteria produce them
  19. 19.  Exospores  formed outside,cut off from  Tip during favourable conditions  Heterocyst  Sometimes during unfavourable conditon  Help in reproduction  Germinate during favourable condition  To new filaments
  20. 20.  Economic importance  1)Important role in evolution of early earth -made earth oxygenic by utilising water for photosynthesis ,fix co2  And liberate oxygen  2)fix atmospheric nitrogen –through heterocyst hence used as biofertilizer.  Azolla is a fast growing free floating freshwater fern which fixes atmospheric nitrogen by forming a symbiotic association with a prokaryotic cyanobacterium -Anabaena azollae. It is a cost-effective, eco-friendly biofertilizer in lowland rice fields. As green manure in water logged soil, it enhances the rapid mineralization of nitrogen, improves the physical and chemical properties of the soil
  21. 21. Paddy field with azolla
  22. 22.  3)Role in bioremidiation  impoving soil quality in saline soils by sodium removal(bioremediation) .eg Phromedium reduces the quality of brine).  4)Used in waste-water treatment too  5)Act as first colonizers in soil reclaimation.  6)Improve water holding capacity  7)Increase soil biomass after their death  8)Used as bio-inoculant- as they produce  bio-active substances such as growth harmones,enzymes (increase yield in paddy), and maintain soil health  9)increase phosphate content in soil  10)prevent soil erosion by binding soil
  23. 23.  9) form base of aquatic food chain act as primary producers.  10)As a part of phytoplanktons contribute in adding oxygen to atmosphere  11)Role as nutritionalfood supplement  Certain species of cyanobacteria serve as food  And nutrtional supplement such as complex sugar,protein,amino acids,active enzymes,phycocyanin,cholorphyll,beta carotene,essential fatty acid minerals,carohydrates and vitamins
  24. 24. 12)Act as SCP( single celled protein) eg.Spirulina and certain species of nostoc (N.commune),  Spirulina are considered super food with excellent nutritional content  High protein and vitamin content.source of B12
  25. 25.  13) species of Lyangbia are used in preparation of antibiotics  14)Many species of cyanobacteria grown in large number form algal blooms in aquatic bodies .they produce potent toxins – hepatotoxin,nerutoxin.  They change quality of water by producing offensive odour,colour and make water unpotable  Cattles and other lifestock when they consume such water are killed  Finally the water body will sustain no life  Due to anoxia.
  26. 26.  The important toxins producing cyanobacteria are Microcytis aeruginosa,  Anabena flosaquae  .
  27. 27.  15)Cyanobacteria can grow on walls and roof of building during rainy season causing discolouration,corrosion and leakage
  28. 28. Synecocystis  13)As a source of bio-fuel –as environmental friendly,cheap source.  Genetically engineered cyanobacteria used a source bio-disel,bio-hydrogen,bio-methane  14)As a tool or model organism for scientific studies  Cyanobacteria such as Synechocystis widely used as system to study principles of photosynthesis  As they can be grown easily in liquid culture and can be manipulated genetically.
  29. 29. Paralellism between bacteriacyanobacteria BACTERIA CYANOBACTERIA 1. Prokaryotic cell (no nuclear membrane,70S ribosome,lack histone protein,no cell organelles,presence of peptidoglycan Prokaryotic cell 2) sensitive to antibiotics Sensitive to antibiotics 3)Lack true sexual reproduction 3)Lack true sexual reproduction 4)Some forms fix atmospheric nitrogen .eg. Rhizobium,Azatobacter 4)Also fix atmospheric nitrogen. Eg.filamentous forms like nostoc,Anabena fix nitrogen 5)Many similar metaboilc processes eg.sulphur and 5)Many similar metaboilc processes eg.sulphur and

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