• Korean Journal of Microbiology
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• v.52 no.3
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• pp.254-259
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• 2016

Acinetobacter sp. B-W producing siderophore, 2, 3-dihydroxybenzoic acid (DHB) was analyzed for plasmid content. Strain B-W harbored plasmid of 20 kb in size. Growth at $43^{\circ}C$ was effective in producing mutant cured of plasmid of strain B-W. This mutant lost the ability to produce 2, 3-DHB. Formation of siderophore halos on the chrome azurol S (CAS) agar medium was not detected by cured strain B-W. pHs of supernatants of wild type strain B-W and cured mutant grown in glucose and $MnSO_4$ containing medium at $28^{\circ}C$ for 3 days were 4.5 and 8.5, respectively. Antibiotic resistance against ampicillin, actinomycin D, bacitracin, lincomycin, and vancomycin was lost in cured mutant. Plasmid curing of strain B-W resulted in drastic reduction of minimal inhibitory concentration (MIC) of several antibiotics. E. coli $DH5{\alpha}$ was transformed with plasmid isolated from strain B-W. The transformant E. coli $DH5{\alpha}$ harbored a plasmid of the same molecular size as that of the donor plasmid. Transformant E. coli $DH5{\alpha}$ produced 2, 3-DHB and contained antibiotic resistant ability. Thus a single plasmid of 20 kb seemed to be involved in 2, 3-DHB production. Genes encoding resistance to antibiotics were also supposed to be located on this plasmid.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.391-396
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• 1992

Anabaena variabilis A TCC 29413. a photoautotrophic and nitrogen fixing cyanobacteria. was investigated on the environmental factors regulating the growth and nitrogen lixation activity. A good growth of cyanobacteria] cells was observed due to nitrogen t1xation by the heterocyst differentiation in nitrogen free Allen and Arnon (]/8) medium. The nitrogenase activity was appeared to be in proportion to the cell growth lor 6 days then drastically decreased in the later growth period when the nitraTe was accumulated to high level in the culture to cause the inhibition. The optima] conditions lilr the cell growth and nitrogenase activity of A. varillbili.l were anaerobic. IO.OO0 lux. $30^{\circ}C$ and pH 8 with the nitrogen Cree minimal medium. The activity was significantly inhihited by the low concentrations of ammonium and nitrate. but was stimulated b) the ]ow Ieve] of phosphate and carbonate sources. The treatments of several toxic heavy metals showed strong inhibition of the cell growth and nitrogenase activity by O.3~10 ppm in the order of $Hg^{2+}$ > $Cd^{2+}$ > $Co^{2+}$ > $Zn^{2+}$ > $Ph^{2+}$, and the concentrations for 50% inhibition of the maximum activity were 0.41. 0.47. 0.5 L 0.66 and 8.1 ppm. respectively. The addition of carbohydrates (0.5~ 1.0%) in the dark condition stimulated the growth and activity in the order of sucrose > fructose > glucose.

• Journal of Microbiology
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• v.44 no.2
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• pp.192-199
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• 2006

Pseudomonas putida KL47 is a natural isolate that assimilates benzene, 1-alkylbenzene $(C_1-C_4)$, biphenyl, p-cumate, and p-cymene. The genetic background of strain KL47 underlying the broad range of growth substrates was examined. It was found that the cym and cmt operons are constitutively expressed due to a lack of the cymR gene, and the tod operon is still inducible by toluene and biphenyl. The entire array of gene clusters responsible for the catabolism of toluene and p-cymene/p-cumate has been cloned in a cosmid vector, pLAFR3, and were named pEK6 and pEK27, respectively. The two inserts overlap one another and the nucleotide sequence (42,505 bp) comprising the cym, cmt, and tod operons and its flanking genes in KL47 are almost identical (>99 %) to those of P. putida F1. In the cloned DNA fragment, two genes with unknown functions, labeled cymZ and cmtR, were newly identified and show high sequence homology to dienelactone hydrolase and CymR proteins, respectively. The cmtR gene was identified in the place of the cmtI gene of previous annotation. Western blot analysis showed that, in strains F1 and KL47, the todT gene is not expressed during growth on Luria Bertani medium. In minimal basal salt medium, expression of the todT gene is inducible by toluene, but not by biphenyl in strain F1; however, it is constantly expressed in strain KL47, indicating that high levels of expression of the todST genes with one amino acid substitution in TodS might provide strain KL47 with a means of adaptation of the tod catabolic operon to various aromatic hydrocarbons.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.128-134
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• 2007

Previously, we isolated plant growth promoting rhizobacterium (PGPR) Bacillus licheniformis K11 which could produce auxin, cellulase and siderophore. The siderophore of B. licheniformis K11 $(siderophore_{K11})$ was determined to be a catechol type siderophore which is produced generally by Bacillus spp. B. licheniformis K11 could produce the siderophore most highly after 96 h of incubation under nutrient broth at $20^{\circ}C$ with initial pH 9.0. For the production of the $siderophore_{K11}$, trehalose and $NH_4Cl$ were the best carbon and nitrogen sources in Davis minimal medium, respectively. The $siderophore_{K11}$ was Produced in M9 medium (pH 9.0) after 4 days at $20^{\circ}C$, and purified from culture broth of B. licheniformis K11 by using Amberlite XAD-2, Sephadex LH-20 column chromatography, and reversed-phase HPLC. The $siderophore_{K11}$ had the biocontrol activity against spore germination of P. capsici and F. oxysporum on potato dextrose agar (PDA). The results indicate that the $siderophore_{K11}$ is an antifungal mechanism of B. licheniformis K11 against phytopathogenic fungi.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.6
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• pp.461-467
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• 2005

Background. 5-(and-6)-carboxy-2',7'-dichlorofluorescein diacetate, succinimidyl ester mixed (CFSE) is the fluorescent labelling agent of living cells and used to trace the cells in vivo after transplatnation of various cells. The CFSE labelled cells can maintain fluorescence for up to 7 days after labelling. The MC3T3-E1 cell line (MC3T3) has been used for many studies about osteoblast, which is well known as a mouse preosteoblast. So the CFSE would be used to trace the transplanted MC3T3. However there are few reports about CFSE labelling of MC3T3. This study is aimed to know about adequate concenturation and incubation time of CFSE to MC3T3. Materials and methods. The MC3T3 was incubated in a humidified atmosphere of 95% air with 5% $CO_2$ at $37^{\circ}C$ using ${\alpha}$-minimal essential medium (${alpha}$-MEM) containing10% FBS and gentamycin. Ten mM CFSE solution in dimethylsulphoxide (DMSO: 1%) was diluted with phosphate buffered saline (PBS) and final concentration of culture medium was, respectively, 5, 10, 15, 20, 25 and 30 ${{\mu}M$. Then the MC3T3 was incubated with CFSE in a humidified atmosphere of 95% air with 5% $CO_2$ at $37^{\circ}C$ for 5, 10, 15, 20, 25, 30, 35, 40 and 45 minutes in each concentration. The fluorescence of CFSE labelled cells was analysed with a inverted fluorescence microscope. The duration of cell labelling was also studied. Trypan blue dye exclusion test was done for cell viability. Results. For concentration between 5 and 10 ${\mu}M$, CFSE did not significantly label the MC3T3 in vitro. The destruction of MC3T3 was observed at the concentration of 20 ${\mu}M$. In the concentration of 15 ${\mu}M$, the best labelling was obtained at an incubation period between 15 and 30 minutes. The MC3T3 labelled with an incubation period of 15 minutes at 15 ${\mu}M$ was still fluorescent 7 days after CFSE labelling. The mean cell viability was 95.93%. Conclusion. These results suggests an incubation period of 15 minutes at 15 ${\mu}M$ of CFSE provides best labelling of MC3T3 in vitro.

• Journal of Life Science
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• v.13 no.4
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• pp.421-427
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• 2003

A natural habit at bacterium, Enterobacter intermedious KH410 was isolated from freshwater plant root and identified. Adsorption of heavy metals such as lead, cadmium, and copper by this strain was examined. The minimal inhibitory concentrations(MIC) for each metal were 1.78 mM for lead, 0.17 mM for cadmium and 1.39 mM for lopper, respectively. Maximum production of dried cell was 2.56 g/$\ell$ in LB medium containing 0.5% NaCl, 1% yeast extract and 1% of lactose. Optimal conditions for adsorption were 0.6 dry g-biomass, at pH 4.0 and the temperature of $20^{\circ}C$. Adsorption equilibrium reached maximum after 30 min in 400 mg/$\ell$ metal solution. The adsorption capacity (K) of copper was 1.5 times higher than that of cadmium and lead was 1.1 times higher than that of cadmium. from the results obtained in this study, Freundlich adsorption model was applicable for all metals. Adsorption strength (1/n) of heavy metal ions were in the order of cadmium>copper>lead. The adsorption of dried cell for lead, cadmium, and copper was 56.2, 58.0, 55.8 mg/g-biomass, respectively. Pretreatment to increase ion strength was the most effective with 0.1 M NaOH whereas slight difference was found both KOH and $CaCl_2$ upon same concentration. Effective desorption was induced by 0.1 M EDTA for lead and 0.1 M $HNO_2$ for cadmium and copper.

• Journal of Plant Biotechnology
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• v.50
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• pp.176-182
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• 2023

Plant regeneration protocols for adventitious shoot organogenesis from apple (Malus domestica 'Fuji') leaf explants were developed in the present study. The effects of dark incubation periods in the early stages of culture, pre-treatment methods, the number of explants per culture container, the type of culture containers, and the orientation of the explants on culture media were evaluated to determine the optimal shoot regeneration conditions for 'Fuji' apple leaf explants. Light incubation of explants produced minimal response. However, dark incubation of explants for 4 weeks during the initial culture period enhanced shoot regeneration frequency. Comparing the number of explants per container, a higher percentage of shoot regeneration was obtained with nine explants per container compared with four explants per container. Pre-treatment, before culture, by dipping explants in a liquid regeneration medium containing 40 g/L of sorbitol for 2 hours produced the highest shoot formation rate, and the time of shoot formation was accelerated. The percentage of shoot regeneration and number of shoots per regenerating explant reached a maximum of 87.5% and 4.7, respectively. The regenerated shoots were elongated and rooted on a rooting medium of 1/4 MS with 0.2 mg/L IBA. The plantlets were successfully acclimatized, and the regenerated plants produced normal phenotypes.

• Molecules and Cells
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• v.20 no.1
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• pp.74-82
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• 2005

Glutaredoxins (Grxs) are thioloxidoreductases which are required for maintaining thiol/disulfide equilibrium in living cells. The Grx3 gene, which encodes one of the three monothiol Grxs in the fission yeast Schizosaccharomyces pombe, was characterized, and its transcriptional regulation studied. Genomic DNA encoding Grx3 was isolated by PCR, and a plasmid pTT3 carrying this DNA was produced. The DNA sequence has 1,267 bp, which would encode a monothiol Grx of 166 amino acids with a molecular mass of 18.3 kDa. The putative protein has 27% homology with Grx5, and contains many hydrophobic amino acid residues in its N-terminal region. S. pombe cells harboring pTT3 had increased Grx activity and enhanced survival on minimal medium plates containing aluminum (5 mM), BSO (0.05 mM), menadione (0.01 mM) or cadmium (0.2 mM). The 568 bp upstream region of Grx3 was fused into the promoterless b-galactosidase gene of the shuttle vector YEp367R to generate fusion plasmid pMJS10. Potassium chloride (KCl) and metals including aluminum and cadmium enhanced the synthesis of ${\beta}$-galactosidase from the fusion gene. The synthesis of ${\beta}$-galactosidase was also enhanced, in a Pap1-dependent manner, by fermentable carbon sources such as glucose (at low concentrations) and sucrose, but not by non-fermentable carbon sources such as ethanol and acetate. Grx3 mRNA increased in response to treatment with BSO. These observations indicate that S. pombe Grx3 is involved in the response to stress, and is regulated by stress.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.616-623
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• 2008

In spite of an increasing interest in fucoidans as biologically active compounds, no convenient commercial sources with fucoidanase activity are yet available. A marine bacterial strain that showed confluent growth on a minimal medium containing fucoidan, prepared from Korean Undaria pinnatifida sporophylls, as the sole carbon source was isolated and identified based on a 16S rDNA sequence analysis as a strain of Sphingomonas paucimobilis, and named Sphingomonas paucimobilis PF-1. The strain depolymerized fucoidan into more than 7 distinct low-molecular-mass fucose-containing oligosaccharides, ranging from 305 to 3,749 Da. The enzyme activity was shown to be associated with the whole cell, suggesting the possibility of a surface display of the enzyme. However, a whole-cell enzyme preparation neither released the monomer L-fucose from the fucoidan nor hydrolyzed the chromogenic substrate p-nitrophenyl-${\alpha}$-L-fucoside, indicating that the enzyme may be an endo-acting fucoidanase rather than an ${\alpha}$-L-fucosidase. Therefore, this would appear to be the first report on fucoidanolytic activity by a Sphingomonas species and also the first report on the enzymatic degradation of the Korean Undaria pinnatifida sporophyll fucoidan. Moreover, this enzyme activity may be very useful for structural analyses of fucose-containing polysaccharides and the production of bioactive fucooligosaccharides.

• Cartoon and Animation Studies
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• s.15
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• pp.73-88
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• 2009

Light is a basic force that functions in all the formative arts. Light (brightness) is an important subject of study in that it contains the force to control emotion and has much influence upon the shaping of a visual image and a feeling. If an artist systematizes the characteristics of brightness and creates an image, he or she can acquire a useful tool of expression. Because light is a powerful medium of expression of a visual image, a study on the characteristics of brightness for the emotional expression of an image in the contextual relationship with narratives seemingly has a crucial meaning. Emotion is influenced by a visual image very much, and a visual image is inevitably influenced by light. The brightness by light is basically classified into bright, dim, and dark. And the three basic stages of brightness specialize an image according to the setting of scope of maximal and minimal luminosity, and the image is further differentiated by the size of bright portion or dark portion. Since emotion is such a phenomenon as immaterial and psychological, it is difficult to break down it. Furthermore, clarifying the principle of an image in which the shade of light is associated is impossible. However, the width of luminosity and the change of size can give quite a change to a visual image, and the visual image has further influence upon man's emotion too. Although the influence of brightness upon a visual image varies with extents, circumstances, and personal tastes and interests, even the same image clearly changes with the adjustment of brightness.