Download Fun with Nif`s

What Are
and what do
they do???
Survive without food?
Legumes like Nitrogen Fixation.
Then, why do Nitrogen Fixing
bacteria exist?
• To give plants the
nitrogen needed to
develop and grow to
many of our favorite
vegetables.
Nitrogen fixating bacteria has specific
genes, Nitrogen Fixing genes (Nifs)
There are many kinds of Nif
Genes!
Such as NifA, NifD, NifK…
Where are Nifs found?
• In some kinds of bacteria.
Example : Anabaena and Azotobacter.
Nitrogen Fixation is done through a
Nitrogenase complex…
But due to the complexity of the
cofactor, there are three kinds…
Most Nitrogen fixing bacteria
has 1 of the 3,
yet, Anabaena has ALL 3
kinds!!!
Then… How did Anabaena acquire
those different Nitrogen Fixing
genes?
• 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.
• 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…
All Anabaena genes evolved from the same
ancestor, while Azotobacter is different…
Or…All Nif genes in Anabaena evolved from
the same ancestor, while Vnf evolved from
same ancestor as for Vnf in Azotobacter
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
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…
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 don’t
share the same ancestors:
Most likely the case.
• In order to answer this complex question,
further research must be done on this
topic to provide enough supporting
evidence.
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 Elhai
Dept. of Biology and Center for the Study of
Biological Complexity
Virginia Commonwealth University