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Thursday, July 5, 2012

PowerPoint Presentation On GENETIC ENGINEERING OF NITROGEN FIXATION

PPT On GENETIC ENGINEERING OF NITROGEN FIXATION
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1. GENETIC ENGINEERING OF NITROGEN FIXATION

 2. Nitrogen Fixation-
Nitrogen fixation is the process by which nitrogen is taken from atmosphere and converted into nitrogen compounds. Biological nitrogen fixation was discovered by the Dutch microbiologist Martinus Beigerinck. Natural processes fix about 190×1012 g yr-1 of nitrogen through the following processes-

3. Types of nitrogen fixation
Lightning 2.Photochemical Reaction 3.Industrial Nitrogen Fixation

4.Biological Nitrogen Fixation

5. Types of Biological Nitrogen Fixation Symbiotic Nitrogen Fixation Nonsymbiotic Nitrogen Fixation Symbiotic Nitrogen Fixation- In symbiotic nitrogen fixation the plant and bacteria depend on each other. Rates of nitrogen fixation are highly variable and are dependent on the bacterial strain-legume cultivar used, soil and other environmental conditions. 100kg of nitrogen are reported to be derived from symbiotic nitrogen fixation.

 6. Continue………………
The highest amount of nitrogen fixed by the legumes takes place either the flowering stage or during pod fill stage. Legume symbioses- eg- rhizobium species Associations with Frankia- Frankia is a group termed Actinomycetes-filamentous bacteria that are noted for their production of air-borne spores. They form nitrogen fixing root nodules with several woody plants.eg-elder,sea buckthorn. Cyanobacterial associations-The photosynthetic cyanobacteria often live as free-living organisms in pioneer habitats such as desert soils or as symbionts with lichens in other pioneer habitats.they form nitrgen fixing nodulation.

7. Nonsymbiotic nitrogen fixation In nonsymbiotic nitrogen fixation the bacteria not associated with plant but they fix nitrogen into the plant. Azotobacter and Azospirillum fix nitrogen into the plant by the nonsymbiotic process. Azospirillum is not only capable of nitrogen fixation but also codes for plant growth hormones auxins and cytokinins. These bacteria are the free living bacteria that fix nitrogen.

8. Mechanism of Nitrogen fixation The biological process of nitrogen fixation is catalyzed by the nitrogenase enzyme, an enzyme complex containing the nitrogenase reductase and dinitrogenase. Nif genes forming a gene cluster of 24 kb nucleotides which are located between the genes encoding for histidine and shikimic acid. The cluster is organized in 7 operons i.e. transcription units (QB AL FM VSUX NE YKDH J). Nif HDKY operon encodes nitrogenase.

 9. Thank You.

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