title: The effect of toxic malachite green on the bacterial community in Antarctic soil and the physiology of malachite green-degrading Pseudomonas sp. MGO.
abstract: The effects of malachite green (MG) on the bacterial community in Antarctic soil were assessed. Culture-independent community analysis using 16S rRNA gene pyrosequencing showed that, in the presence of MG, the relative abundance of Pseudomonas dramatically increased from 2.2 % to 36.6 % (16.6-fold), and Pseudomonas became the predominant genus. The reduction in bacterial biodiversity was demonstrated by diversity indices and rarefaction curves. MG-degrading Pseudomonas sp. MGO was isolated from Antarctic soil. MG tolerance and decolorization activity were confirmed by growth, spectrophotometric, high-performance liquid chromatography, and thin-layer chromatography analyses in high MG concentrations. Our data showed that the decolorization process occurred via biodegradation, while biosorption also occurred after some time during the fed-batch decolorization process. Significant inductions in laccase, nicotinamide adenine dinucleotide-2,6 dichlorophenol indophenol reductase, and MG reductase activities suggested their involvement in the decolorization process. We also showed that the high tolerance of strain MGO to toxic MG might be mediated by upregulation of oxidative stress defense systems such as superoxide dismutase and protease. Collectively, these results demonstrated the response of the Antarctic soil bacterial community to MG and provided insight into the molecular mechanism of MG-tolerant Pseudomonas strains isolated from Antarctic soil.
authors.affiliation: Department of Environmental Science and Ecological Engineering, Korea University, Seoul 136-713, Republic of Korea.
authors.forename: Jaejoon
authors.initials: J
authors.lastname: Jung
authors.forename: Hyoju
authors.initials: H
authors.lastname: Seo
authors.forename: Se Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Che Ok
authors.initials: CO
authors.lastname: Jeon
authors.forename: Woojun
authors.initials: W
authors.lastname: Park
mesh_terms: D000864:Antarctic Regions; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D011549:Pseudomonas / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D012394:Rosaniline Dyes / Q000378:metabolism / Q000633:toxicity*; D012988:Soil Microbiology
chemical_list: D017931:DNA Primers; D012394:Rosaniline Dyes; C005095:malachite green