The role of the ferric uptake gene (fur) in burkholderia sp. usm b20

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Date
2014
Authors
Mohamad, Ahmad Faisal
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Iron is an element that plays an important role in biochemical reactions in all living things. The lack of this element stimulates a pathogenic bacterium to release virulent factors in order to survive. This study was conducted to observe the role of a ferric ion transport regulator gene named fur in bacterial virulence. Strain Burkholderia sp. USM B20 which was isolated from a leguminous plant Mucuna bracteata was used as a model microorganism. Sequence analysis of the 16S rDNA of this bacterium showed that it shared 99% identity with Burkholderia vietnamiensis. To elucidate the role of the fur gene, a mutant strain was formed. A plasmid called pTS414 which carried the levan sucrase and trimethoprim antibiotic resistance genes were constructed. This antibiotic resistance trimethoprim gene was regulated by a promoter derived from the B. vietnamiensis 16S rDNA gene. This gene was found to function in Burkholderia sp. B20. Subsequently, the DNA present on the left and right of the fur gene were cloned so that the fur gene was flanked in the plasmid. This assembly was done to develop an allele replacement vector to mutate the chromosomal copy of the fur gene in Burkholderia sp. B20. This allele replacement vector was transformed into Escherichia coli S17 lambda pir and subsequently moved into Burkholderia sp. USM B20 through conjugation. A fur- mutant that had the fur gene replaced with the trimethoprim resistant gene was successfully generated. Validation of this mutant was done using PCR. A comparative study showed that biofilm production by this mutant was evidently lower than the wild type strain. This mutant is also unable to produce a quorum sensing signal. No change was seen in the production of protease and lipase enzymes. As a whole, it can be described that the fur gene influences a several of features in Burkholderia sp. B20 with respect to virulence.
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