title: The unique role of siderophore in marine-derived Aureobasidium pullulans HN6.2.
abstract: The L -ornithine-N (5)-monooxygenase structural gene (SidA gene, accession number: FJ769160) was isolated from both the genomic DNA and cDNA of the marine yeast Aureobasidium pullulans HN6.2 by inverse PCR and RT-PCR. An open reading frame of 1,461 bp encoding a 486 amino acid protein (isoelectric point: 7.79) with calculated molecular weight of 55.4 kDa was characterized. The promoter of the gene (intronless) was located from -1 to -824 and had three HGATAR boxes which were putative binding motifs for the respective DNA-binding motifs and one CATA box. The SidA gene in A. pullulans HN6.2 was disrupted by integrating the hygromycin B phosphotransferase (HPT) gene into Open Reading Frame of the SidA gene using homologous recombination. Of all the disruptants obtained, one strain S6 (∆sidA) did not synthesize both intracellular and extracellular fusigen so that it could not inhibit growth of the pathogenic bacteria Vibrio anguillarum and Vibrio parahaemolyticus. The disruptant S6 did not grow in the iron-deplete medium and seawater medium because cell budding was stopped, but could grow in the iron-replete medium with 10 μM Fe(3+) and Fe(2+). H(2)O(2) in the medium was more toxic to the disruptant S6 than to its wild type HN6.2. Thus, we infer that the fusigen produced by the marine-derived A. pullulans HN6.2 can play a unique role in chelating, uptake and concentration of iron to maintain certain proper physiological functions within the cells and secretion of siderophore may represent an efficient tool to eliminate competitors to compete for limiting nutritional resources in marine environments.
authors: Unesco Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
authors: Zhe
authors: Z
authors: Chi
authors: Xing-Xing
authors: XX
authors: Wang
authors: Zai-Chao
authors: ZC
authors: Ma
authors: Muhammad Aslam
authors: MA
authors: Buzdar
authors: Zhen-Ming
authors: ZM
authors: Chi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001203:Ascomycota / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology; D012623:Seawater / Q000382:microbiology*; D017262:Siderophores / Q000235:genetics / Q000378:metabolism*; D014733:Vibrio / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D016877:Oxidants; D017262:Siderophores; D006861:Hydrogen Peroxide; D007501:Iron