• Journal of Life Science
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• v.14 no.4
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• pp.582-588
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• 2004

Eighty one bacterial strains of parathion degrading bacteria were isolated from soil samples that were contaminated with pesticide in Daejeon area. Among them, one bacterial strain was finally selected in media containing parathion as the sole source of carbon and energy, and this strain was identified as Pseudomonas rhodesiae H5 through physiological and biochemical tests, and analysis of its 16S rRNA sequence. Pseudomonas rhodesiae H5 was able to utilize various carbohydrates but did not utilize sorbose as sole carbon source. Pseudomonas rhodesiae H5 was resistance to ampicillin, spectinomycin, and mitomycin C but sensitive to kanamycin and chloramphenicol. And this strain showed high resistance up to several milligrams of heavy metals such as $BaCl_2$, LiCl, and $MnSO_4$. Optimal growth condition for temperature and pH of P. rhodesiae H5 was 3$0^{\circ}C$, and pH 7.0, respectively. It can be presumed that P. rhodesiae H5 hydrolyzed an organophosphate bond of parathion, forming p-nitrophenol, and then metabolized via ortho-ring cleavage mechanism.

• Korean Journal of Environmental Agriculture
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• v.20 no.2
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• pp.74-78
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• 2001

Two Bacterial strains 1-C and 51-C capable of utilizing aniline as a sole source of carbon and energy were isolated from river waters. Both strains were identified as Pseudomonas rhodesiae based on their physiological and biochemical characteristics and 16S rRNA gene sequence. The strains were able to grow on the mineral salt media containing aniline at concentrations up to 6,000 ${\mu}g/mL$. Pseudomonas rhodesiae 51-C completely degraded aniline in a mineral salt medium containing 300 ${\mu}g/mL$ of aniline as a sole carbon and energy source within 16 hours. The optimum pH and temperature for its growth and aniline degradation were 7.0 and $30^{\circ}C{\sim}35^{\circ}C$, respectively. This is the first report of aniline degradation by P. rhodesiae strains.

• Journal of Life Science
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• v.26 no.1
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• pp.75-82
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• 2016

Pseudomonas rhodesiae KK1 has been reported to degrade polycyclic aromatic hydrocarbons (PAHs), such as anthracene, naphthalene, and phenanthrene, which are considered major environmental contaminants. Interestingly, antioxidant genes, including superoxide dismutase, are known to be expressed at different levels in response to environmental contaminants. This study was performed to identify the superoxide dismutase gene in strain KK1, which may be indirectly involved with degradation of PAHs, as well as to investigate the expression pattern of the superoxide dismutase gene in cells grown on different PAHs. Two types of superoxide dismutase genes responsible for the antioxidant defense mechanism, Mn-superoxide dismutase (sodA) and Fe-superoxide dismutase (sodB), were identified in P. rhodesiae KK1. The sodA gene in strain KK1 shared 95% similarity, based on 141 amino acids, with the Mn-sod of P. fluorescens Pf-5. The sodB strain, based on 135 amino acids, shared 99% similarity with the Fe-sod of P. fluorescens Pf-5. Southern hybridization using the sod gene fragment as a probe showed that at least two copies of superoxide dismutase genes exist in strain KK1. RT-PCR analysis revealed that the sodA and sodB genes were more strongly expressed in response to naphthalene and phenanthrene than to anthracene. Interestingly, sodA and sodB activities were revealed to be maintained in cells grown on all of the tested substrates, including glucose.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.199-204
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• 2004

The parathion hydrolase (OPH) produced by Pseudomonas rhodesiae H5 was purified by ammonium sulfate precipitation, DEAE-Toyopearl 650M ion exchange chromatography and Sephadex gel filtration chromatography. Parathion hydrolase from crude extracts of P. rhodesiae H5 has two components designated as OPH $I_1$ and OPH $I_2$, Optimum pH and temperature of OPH $I_1$and OPH $I_2$ were pH 7.2 and $30^{\circ}C$, and pH 7.6 and $37^{\circ}C$, respectively. The activation energy of OPH $I_1$ for the hydrolysis of parathion was 3.01 ㎉/I, II, III in the temperature range of $4^{\circ}C$ to $30^{\circ}C$, and Michaelis constant ($K_m$) for parathion was 69.2 ${\mu}M$. The activation energy of OPH $I_2$ for the hydrolysis of parathion was 4.07㎉/㏖ in the temperature range of $4^{\circ}C$ to $37^{\circ}C$, and Michaelis constant for parathion was 150.9${\mu}M$. Furthermore OPH $I_1$ was completely inhibited by 1 mM $Ca^2+$, $Cu^2+$, $Mg^2+$, $Ni^2+$, but OPH $I_2$ was less inhibited than OPH $I_1$ by the metals used in this study.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.117-119
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• 2005

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.66-72
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• 2007

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immune-stimulation activities. In this study, antibacterial activities of 800 more natural plant extracts against yam-putrefactive psychrotrophic bacterium, Pseudomonas rhodesiae YAM-12, were evaluated to select a natural preservative, which is useful to long-term storage of yam and fresh-cut production. Finally, the clove oil was selected, and applied for the production of yam fresh-cut. The 1% of clove oil treated fresh-cut showed minor color changes during 31 days storage at $4^{\circ}C$ and the microbial growth was not detected. When the artificially contaminated fresh cut by dipping with P. rhodesiae YAM-12 suspension for 3 min was treated 1% clove oil, the microbial growth was identified to $10^4$ CFU/g from $10^3$ CFU/g with minor color changes. Whereas, treatment of sterilized water, or 100 ppm NaOCl into artificially contaminated fresh cut showed severe putrefaction $(10^8\;CFU/g)$ and color changes. Considering the previous reports that clove oil has antimicrobial, antioxidation, and antithrombosis activity, the use of clove oil into the yam fresh cut will provide market safety and consumer acceptability by prevention of microbial putrefaction and its biological activity.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.96-103
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• 2007

Plant growth-promoting rhizobacteria (PGPR) have the potential to be used as microbial inoculants to reduce disease incidence and severity and to increase crop yield. Some of the PGPR have been reported to be able to enter plant tissues and establish endophytic populations. Here, we demonstrated an approach to screen bacterial endophytes that have the capacity to promote the growth of pepper seedlings and protect pepper plants against a bacterial pathogen. Initially, out of 150 bacterial isolates collected from healthy stems of peppers cultivated in the Chungcheong and Gyeongsang provinces of Korea, 23 putative endophytic isolates that were considered to be predominating and representative of each pepper sample were selected. By phenotypic characterization and partial 16S rDNA sequence analysis, the isolates were identified as species of Ochrobacterium, Pantoea, Pseudomonas, Sphingomonas, Janthinobacterium, Ralstonia, Arthrobacter, Clavibacter, Sporosarcina, Acidovorax, and Brevundimonas. Among them, two isolates, PS4 and PS27, were selected because they showed consistent colonizing capacity in pepper stems at the levels of $10^6-10^7CFU/g$ tissue, and were found to be most closely related to Pseudomonas rhodesiae and Pantoea ananatis, respectively, by additional analyses of their entire 16S rDNA sequences. Drenching application of the two strains on the pepper seedlings promoted significant growth of peppers, enhancing their root fresh weight by 73.9% and 41.5%, respectively. The two strains also elicited induced systemic resistance of plants against Xanthomonas axonopodis pv. vesicatoria.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.729-734
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• 2002

Radiorespirometric analysis revealed that Pseudomonas sp. strain KKI isolated from a soil contaminated with petroleum hydrocarbons was able to catabolize polycyclic aromatic hydrocarbons such as phenanthrene and naphthalene. The rate and extent of phenanthrene mineralization was markedly enhanced when the cells were pregrown on either naphthalene or phenanthrene, compared to the cells grown on universal carbon sources (i.e., TSA medium). Deduced amino acid sequence of the Rieske-type iron-sulfur center of a putative phenanthrene dioxygenase (PhnAl) obtained from the strain KKI shared significant homology with DxnAl (dioxin dioxygenase) from Spingomonas sp. RW1, BphA1b (biphenyl dioxygenase) from Spingomonas aromaticivorans F199, and PhnAc (phenanthrene diokygenase) from Burkholderia sp. RP007 or Alcaligenes faecalis AFK2. Northern hybridization using the dioxygenase gene fragment cloned from KKI showed that the expression of the putative phn dioxygenase gene reached the highest level in cells grown in the minimal medium containing phenanthrene and $KNO_3$, and the expression of the phn gene was repressed in cells grown with glucose. In addition to the metabolic change, phospholipid ester-linked fatty acids (PLFA) analysis revealed that the total cellular fatty acid composition of KKI was significantly changed in response to phenanthrene. Fatty acids such as 14:0, 16:0 3OH, 17:0 cyclo, 18:1$\omega$7c, 19:0 cyclo increased in phenanthrene-exposed cells, while fatty acids such as 10:0 3OH, 12:0, 12:0 2OH, 12:0 3OH, 16:1$\omega$7c, 15:0 iso 2OH, 16:0, 18:1$\omega$6c, 18:0 decreased.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.109-114
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• 2006

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immuno-stimulation activities, and its consumption has been increased during last decades. In this study, to investigate low-temperature, long-term storage of yam and to develop processed yam products, yam-putrefactive psychrotrophic bacteria were isolated from rotted yam and identified based on BBL identification system, fatty acid analysis in cell membrane and 16S rDNA sequence analysis. The putrefaction activity of isolated thirteen bacteria was evaluated using yam-slices (NaOCl-treated, autoclaved yam and without treatment), and YAM-10 and YAM-12 were identified as major psychrotrophic putrefactive bacteria. Both YAM-10 (Pseudomonas cepacia) and YAM-12 (Pseudomonas rhodesiae) bacteria grew well at 4$\sim$12$^{\circ}C$ and showed strong activity of polymer degrading enzymes, especially amylase, carboxy methyl cellulase and xylanase, at 20$^{\circ}C$. But they failed to grow at acidic pH (<5) or alkaline pH (>10). Our results suggested that the control of psychrotrophic Pseudomonas sp. by pH change and inhibition of polymer degrading enzymes, such as amy-lase, are necessary to long-term storage of yam.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.130.2-131
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• 2000

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