[Effects of sigma38 subunit deletion of RNA polymerase on antibiotics biosynthesis in pseudomonas].
With the designed primers, PCR was carried out using the genomic DNA of Pseudomonas sp. M18 as a template and a 378bp DNA fragment of the rpoS gene was amplified. Then, a 3. 1kb EcoR I -Xho I fragment containing the rpoS gene and its flanking sequence was obtained by screening the genomic DNA library of Pseudomonas sp. M18.A sigma38-subunit-deficient mutant M18S was constructed with insertional gentamycin gene cassette. In PPM medium, the mutant M18S produced 20.4 microg/mL of PCA and 75 microg/mL of Plt. In KMB medium, the mutant M18S produced no PCA and 185.6 microg/mL of Pit. It is obvious that the deficiency of sigma38 subunit in the mutant M18S leads less or no PCA production and much more Plt production than those in the wild type strain M18. PCA and Plt production were restored to the levels in wild type strain after complementation with rpoS gene in trans in strain M18S. Moreover, beta-galactosidase activities of the translational fusions phzA'-'lacZ and pltA'-'lacZ in strain M18S confirmed the effects of sigma38 subunit on PCA and Plt biosynthetic operons. With these results, it is suggested that sigma38 subunit gives a differential impacts on PCA and Plt biosynthesis, i. e, PCA production is positively regulated but Plt production is negatively influenced by sigma38 subunit in Pseudomonas sp. M18.
Ge
Yi-he
YH
School of Life Science, Ludong University, Yantai 264025, China. geyihe@126.com
Pei
Dong-li
DL
Zhang
Xue-hong
XH
Xu
Yu-quan
YQ
D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000502:physiology; D009154:Mutation; D010619:Phenazines / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D021122:Protein Subunits; D011549:Pseudomonas / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism*; D012808:Sigma Factor / Q000737:chemistry* / Q000502:physiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010619:Phenazines; D010636:Phenols; D021122:Protein Subunits; D011758:Pyrroles; D012808:Sigma Factor; C095503:pyoluteorin; C069567:sigma factor KatF protein, Bacteria; C037165:1-phenazinecarboxylic acid