Fun%20with%20Nif

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Fun With Nifs!!!
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What Are and what do they do???
Nifs
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• Survive without food?

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• Legumes like Nitrogen Fixation.

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Then, why do Nitrogen Fixing bacteria exist?

• To give plants the nitrogen needed to develop and
  grow to many of our favorite vegetables.

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Nitrogen fixating bacteria has specific genes,
Nitrogen Fixing genes (Nifs)
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There are many kinds of Nif Genes!Such as NifA,
NifD, NifK
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Where are Nifs found?

• In some kinds of bacteria.
• Example Anabaena and Azotobacter.

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Nitrogen Fixation is done through a Nitrogenase
complex
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But due to the complexity of the cofactor, there
are three kinds
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Most Nitrogen fixing bacteria has 1 of the
3,yet, Anabaena has ALL 3 kinds!!!
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Then How did Anabaena acquire those different
Nitrogen Fixing genes?
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• First, let us look at the genes of Azotobacter
  Vinelandii (which is not a cyanobacterium) that
  contains Nifs and alternatives, Anfs and Vnfs.
• Then, Let us compare its genes to genes of
  Anabaena.

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• Do you think there is a similarity between their
  Nifs? How about between Vnfs or Anfs of Azobacter
  and Nifs of Anabaena?
• Considering that they are all Nitrogen Fixing
  genes, one would expect one of two possibilities
  

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All Anabaena genes evolved from the same
ancestor, while Azotobacter is different
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OrAll Nif genes in Anabaena evolved from the
same ancestor, while Vnf evolved from same
ancestor as for Vnf in Azotobacter
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How do we compare them?

• To understand where it all came from, a TREE must
  be constructed to compare Azotobacter gene
  sequence with Cyanobacter gene sequence.
• By Run-Phylip, or Make-Tree

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Go to biolingua

• Bring genes of Azotobacter to biolingua.
• BLAST them against Cyanobacteria
• Add them together, then ALIGN.
• Finally, make a tree.
• Giving the following actual results

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So, how did Anabaena acquire those different
Nitrogen Fixing genes?

• Anabaena genes and Azotobacter genes can share
  the same ancestors
• Maybe.
• Anabaena genes and Azotobacter genes dont share
  the same ancestors
• Most likely the case.

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• In order to answer this complex question, further
  research must be done on this topic to provide
  enough supporting evidence.

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Special Thanks to

• Dr. Teresa Thiel Associate Dean, College of Arts
  and Sciences Professor of Biology Department of
  Biology University of Missouri-St. Louis
• And
• Dr. Jeff ElhaiDept. of Biology and Center for
  the Study of Biological ComplexityVirginia
  Commonwealth University