TRANSCRIPTIONAL ANALYSIS OF HYDROGENASE GENES
IN RHODOBACTER SPHAEROIDES O.U.001
In photosynthetic non-sulphur bacteria, hydrogen production is catalyzed by
nitrogenases and hydrogenases. Hydrogenases are metalloenzymes that are basically
classified into: the Fe hydrogenases, the Ni-Fe hydrogenases and metal-free
hydrogenases. Two distinct Ni-Fe hydrogenases are described as uptake
hydrogenases and bidirectional hydrogenases. The uptake hydrogenases are
membrane bound dimeric enzymes consisting of small (hupS) and large (hupL)
subunits, and are involved in uptake and the recycling of hydrogen, providing energy
for nitrogen fixation and other metabolic processes.
In this study the presence of the uptake hydrogenase genes was shown in
Rhodobacter sphaeroides O.U.001 strain for the first time and hupS gene sequence
was determined. The sequence shows 93% of homology with the uptake hydrogenase
hupS of R.sphaeroides R.V.
There was no significant change in growth of the bacteria at different
concentrations of metal ions (nickel, molybdenum and iron in growth media).
The effect of metal ions on hydrogen production of the organism was also
studied. The maximum hydrogen gas production was achieved in 8.4µ / M of nickel
and 0.1 mM of iron containing media.
The expression of uptake hydrogenase genes were examined by RT-PCR.
Increasing the concentration of Ni++ up to 8.4µ / M increased the expression of uptake
hydrogenase genes (hupS). At varied concentrations of Fe-citrate (0.01 mM-0.1 mM)
expression of hupS was not detected until hydrogen production stopped. These
results will be significant for the improvement strategies of Rhodobacter sphaeroides
O.U.001 to increase hydrogen production efficiency.
In order to examine the presence of hupL genes, different primers were
designed. However, the products could not be observed by PCR.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12605336/index.pdf |
| Date | 01 July 2004 |
| Creators | Dogrusoz, Nihal |
| Contributors | Gunduz, Ufuk |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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