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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Microbiology and Biotechnology Letters
Journal Basic Information
Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 40, Issue 4 - Dec 2012
Volume 40, Issue 3 - Sep 2012
Volume 40, Issue 2 - Jun 2012
Volume 40, Issue 1 - Mar 2012
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Isolation and Identification of Agarose-degrading Bacterium, Pseudoalteromonas sp. GNUM08122
Kim, Yu-Na ; Jeong, Yeon-Kyu ; Kim, Mu-Chan ; Kim, Sung-Bae ; Chang, Yong-Keun ; Chi, Won-Jae ; Hong, Soon-Kwang ; Kim, Chang-Joon ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 1~9
DOI : 10.4014/kjmb.1112.12002
This study's aim was to isolate microorganisms producing agarase with a high activity, with possible applications in improving the performance of the pretreatment processes for bioethanol production. Marine algaes were collected from the south coast of Korea, from which three kinds of microorganisms were isolated. After a 4-day culture of these strains at
, crude enzymes were obtained from culture supernatant or cell-free extract by ammonium sulfate precipitation and membrane dialysis. Agarase activity was observed in these crude enzymes. Notably higher specific activity was observed in the crude enzyme obtained from the culture supernatant rather than that from the cell-free extract. This indicates that a secreted enzyme has a much greater activity than a cellular enzyme. Crude enzymes from the GNUM08122 strain were inferred to have
-agarase activity because release of p-nitrophenol was observed, possibly due to the cleavage of p-nitrophenyl-
-D-galactopyranoside. The 16S rRNA sequence of GNUM08122 showed a close relationship to Pseudoalteromonas issachenkonii KMM 3549 (99.8%) and Pseudoalteromonas tetraodonis IMA 14160 (99.7%), which led us to assign it to the genus Pseudoalteromonas. Biochemical and physiological study revealed that this strain can grow well at
under a wide range of pH (pH 4~8) in high-salt conditions (10% NaCl).
Heterologous Expression of a Model Polyketide Pathway in Doxorubicin-overproducing Streptomyces Industrial Mutants
Kim, Hye-Jin ; Lee, Han-Na ; Kim, Eung-Soo ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 10~16
DOI : 10.4014/kjmb.1201.01002
The Streptomyces peucetius OIM (Overproducing Industrial Mutant) strain is a recursively-mutated and optimally-screened strain used for the industrial production of polyketide antibiotics, such as doxorubicin (DXR). Using the S. peucetius OIM mutant strain as a surrogate host, a model minimal polyketide pathway for aloesaponarin II, an actinorhodin shunt product, was cloned in a high-copy conjugative plasmid, followed by functional pathway expression and quantitative metabolite analysis. The level of aloesaponarin II production was noted as being significantly higher in the OIM strain than in the wild-type S. peucetius, as well as in the regulatory network-stimulated S. coelicolor mutant strain. Moreover, the aloesaponarin II production level was seen to be even higher in a down-regulator
-deleted S. peucetius OIM strain, implying that the rationally-engineered S. peucetius OIM mutant strain could be used as an efficient surrogate host for the high expression of foreign polyketide pathways.
-Galactosidase from Bacillus licheniformis Isolated from Cheongkookjang
Yoon, Ki-Hong ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 17~22
DOI : 10.4014/kjmb.1202.02002
A bacterial strain was isolated from homemade Cheongkookjang as a producer of the
-galactosidase, capable of hydrolyzing lactose to liberate galactose and glucose residues. The isolate YB-1105 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties.
-Galactosidase activity was detected in both the culture supernatant and the cell extract of B. licheniformis YB-1105. The enzymes of both fractions demonstrated maximum activity for hydrolysis of para-nitrophenyl-
) under identical reaction conditions of pH 6.5 and
-galactosidase activity from the culture filtrate was affected more than that from the cell free extract at acidic pHs and high temperatures. The hydrolyzing activity of both
-galactosidases for pNP-
was dramatically decreased by the addition of low concentrations of galactose, but was only marginally decreased by high concentrations of glucose or mannose.
Detection of Endolichenic Fungi Producing Antifungal Compound
Kim, Eun-Sung ; Choi, Kap-Seong ; Choi, Sang-Ki ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 23~29
DOI : 10.4014/kjmb.1201.01001
To isolate a novel antifungal compound, we obtained 100 kinds of endolichenic fungi from Korean Lichen & Allied Bioresources Center and examined their antifungal capability. Three fungi Usnea rigidula (2326), Parmotrema pseudotinctorum (2202) and Myelochroa sp. (2292) showed high antifungal activity against Candida albicans when they grew in both liquid and solid media. We extracted the culture supernatants of these three fungi with chloroform and then with ethyl acetate. Chloroform fraction exhibited the highest antifungal activities when those fractions were examined for the growth inhibition of Candida albicans with disc diffusion method. The chloroform faction was on further analysis with
column chromatography to see whether the inhibitors are already known or not. Two peak fractions were collected from 4-day culture extract for Usnea rigidula and from 6-day culture extract for Parmotrema pseudotinctorum on the HPLC. A peak fraction from chloroform extracts of 4-day culture filtrate of Parmotrema pseudotinctorum showed higher antifungal activities against C. albicans and C. glabrata than another peak fraction. It appears that the antifungal materials are relatively nonpolar as usnic acid often found in lichenic fungi.
Effects on the Soil Microbial Diversity and Growth of Red Pepper by Treated Microbial Agent in the Red Pepper Field
An, Chang-Hwan ; Lim, Jong-Hui ; Kim, Yo-Hwan ; Jung, Byung-Kwon ; Kim, Jin-Won ; Kim, Sang-Dal ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 30~38
DOI : 10.4014/kjmb.1110.10007
We investigated the effects on soil microbial diversity and the growth promotion of red pepper resulting from inoculation with a microbial agent composed of Bacillus subtilis AH18, B. licheniformis K11 and Pseudomonas fluorescens 2112 in a red pepper farming field. Photosynthetic bacteria, Trichoderma spp., Azotobacter spp., Actinomycetes, nitrate oxidizing bacteria, nitrite oxidizing bacteria, nitrogen fixing bacteria, denitrifying bacteria, phosphate solubilizing bacteria, cellulase producing bacteria, and urease producing bacteria are all indicator microbes of healthy soil microbial diversity. The microbial diversity of the consortium microbial agent treated soil was seen to be 1.1 to 14 times greater than soils where other commercial agent treatments were used, the latter being the commercial agent AC-1, and chemical fertilizer. The yield of red pepper in the field with the treated consortium microbial agent was increased by more than 15% when compared to the other treatments. Overall, the microbial diversity of the red pepper farming field soil was improved by the consortium microbial agent, and the promotion of growth and subsequent yield of red pepper was higher than soils where the other treatments were utilized.
Development of a Method for High throughput Screening of Antagonistic Substances against Rice Pathogens using Rice Leaf Explants
Park, Sait-Byul ; Lee, Choong-Hwan ; Kim, Tae-Jong ; Kang, Lin-Woo ; Lee, Byoung-Moo ; Kim, Jeong-Gu ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 39~42
DOI : 10.4014/kjmb.1110.10005
A new method for the high throughput screening of antagonistic substances against rice pathogens using rice leaf explants was developed. This method can be used to confirm the activities of any compound or mixture suppressing rice bacterial blight (BB) before field tests. Xanthomonas oryzae pv. oryzae (Xoo) culture medium was distributed in 96 well plates with equally sized explants and the active compounds were added to the wells. The strength suppressing BB was converted into an area percent of the lesion on the rice explants. The explants under BB suppressing activity remained uninfected maintaining their actual green color, while infected explants exhibited pale yellow-colored lesions. Based on the results, this method seems to be faster and easier, dose-dependent, and can be performed all-at-once with a small amount of unspecified compounds. This method also has the potential to be applied to inspection activities for the suppression of other waterborne crop diseases.
Antibacterial Activity of Hippophae rhamnoides Leaf Extract and the Stability of a Cream with the Extract
Chae, Kyo-Young ; Kim, Jung-Eun ; Park, Soo-Nam ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 43~49
DOI : 10.4014/kjmb.1201.01004
In this study, we investigated the antibacterial activity and stability of a cream containing Hippophae rhamnoides leaf extract. The MIC values of ethyl acetate fraction from an H. rhamnoides leaf on Escherichia coli, Pityrosporum ovale, Propionibacterium acnes and Staphylococcus aureus were 0.5%, 0.25%, 0.25% and 0.06%, respectively. Stability evaluations, pH, viscosity and absorbance of the cream containing 0.25% ethyl acetate fraction of H. rhamnoides, were performed. The cream was measured under 4 different temperature conditions under sunlight at 2-week intervals for 12 weeks. The viscosity and pH were measured by a comparison of the experimental cream with a similar control cream. The H. rhamnoides extract was found to have contributed to the stability of the emulsion product via a protective effect in maintaining the viscosity of the cream against sunlight. The absorbance variations of the experimental cream at 270 nm were, under sunlight;
. In addition, any change in color or smell was not observed through the 12 weeks of the experimental period. These results indicated that the cream containing 0.25% ethyl acetate fraction of H. rhamnoides leaf extract was stable. Accordingly, this suggests that further study is needed to provide additional information for manufacturers, who are seeking the application of the extract to improve anti-oxidant and antibacterial activities and the stability of cosmetic products.
Silybin Synergizes with Wnt3a in Activation of the Wnt/
-catenin Signaling Pathway through Stabilization of Intracellular
Kim, Tae-Yeoun ; Oh, Sang-Taek ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 50~56
DOI : 10.4014/kjmb.1202.02007
-catenin signaling pathway regulates diverse developmental processes and adult tissue homeostasis. Inappropriate regulation of this pathway has been associated with human diseases, such as cancers, osteoporosis, and Alzheimer's disease. Using a cell-based chemical screening with natural compounds, we discovered silybin, a plant flavonoid isolated from the Silybum marianum, which activated the Wnt/
-catenin signaling pathway in a synergy with Wnt3a-conditioned medium (Wnt3a-CM). In the presence of Wnt3a-CM, silybin up-regulated
-catenin response transcription (CRT) in HEK293-FL reporter cells and 3T3-L1 preadipocytes through stabilization of intracellular
-catenin protein. Silybin and Wnt3a-CM synergistically reduced expression of important adipocyte marker genes including peroxisome-proliferator-activated
) and CAATT enhancer-binding protein
) in 3T3-L1 preadipocytes, accompanied by the activation of Wnt/
-catenin signaling pathway. Taken together, our findings indicate that silybin is a small-molecule synergist of the Wnt/
-catenin signaling pathway and can be used as a controllable reagent for investigating biological processes that involve the Wnt/
-catenin signaling pathway.
Isolation and Characterization of Antifungal Compounds Produced by Bacillus polyfermenticus CJ6 Isolated from Meju
Yang, Eun-Ju ; Ma, Seung-Jin ; Chang, Hae-Choon ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 57~65
DOI : 10.4014/kjmb.1203.03001
Antifungal compounds from Bacillus polyfermenticus CJ6 were purified using SPE, preparative HPLC, and reverse phase-HPLC. Antifungal compounds from B. polyfermenticus CJ6 were separated into three fractions (8, B, C) using preparative HPLC. LC/MS analysis of antifungal peaks suggested that B. polyfermenticus CJ6 produces lipopeptides; two kinds of iturin A (
), three kinds of surfactins (
), four kinds of fengycin A (
) and two kinds fengycin B (
). The antifungal activity of fraction 8, which was presumed as inturin A, was found to be stable after the pH, heat or proteolytic enzyme treatment, but it was unstable at 50-
for 24 hr. The antifungal activity of fraction B, which presumed as surfactins and fengycin A, was found to be stable after the heat treatment, but it was unstable in the pH 3.0 and after the protease (type I) or
-chymotrypsin treatment. The antifungal activity of fraction C, which was presumed as fengycin A and B, was found to be stable in the pH 3.0-9.0 range and the heat treatment, but it was unstable with the treatment of protease (type I). The amino acid composition of the purified peaks 8-1 and 8-2 were Asx, Tyr, Gln, Pro, and Ser in a molar ratio of 3:1:1:1:1, which showed the same amino acid composition as iturin. From these results, we confirmed that antifungal compounds from B. polyfermenticus CJ6 most likely belonged to iturin A as well as surfactins and fengycins. As lipopeptides are known to act in a synergistic manner, the antifungal compounds from B. polyfermenticus CJ6 might have potential uses in biotechnology and biopharmaceutical applications.
Antifungal Property of Microorganisms against Korea Oak Wilt Pathogen, Raffaelea quercus-mongolicae
Lee, Sang-Hyun ; Lee, Seung-Kyu ; Kim, Jae-Young ; Lee, Chong-Kyu ; Kim, Kyung-Hee ; Yi, Yong-Sub ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 66~69
DOI : 10.4014/kjmb.1110.10003
Five strains out of 200 candidate strains (SG 1-9, 1-12, SG 2-8, 2-10, and 2-17) were selected to determine their antifungal activity against Raffaelea quercus-mongolicae. The 16S rDNA sequences of the five strains were determined by sequencing analysis and analyzed by the homology of the blast program at NCBI. The homology search showed that SG 1-9 and 1-12 had a 98% homology with Streptomyces cinnamoneus and 98% homology with Burkholderia cepacia, while SG 2-8, 2-10, and 2-17 had a 99% homology with Streptomyces fradiae, a 97% homology with Staphylococcus epidermidis, and a 99% homology with Staphylococcus epidermidis. Out of the five selected strains, organic extract and protein extracts of SG2-17 strain broth were employed to determine antifungal activity against Raffaelea quercus-mongolicae. The organic extract exhibited antifungal activity, but the protein extracts did not demonstrate such an activity. Three organic solvents, butanol, benzene, and ethyl acetate, were also used for determination of antifungal activities. The activity measurements revealed that benzene extract possessed the greatest inhibitory effect on the growth of Raffaelea quercus-mongolicae, with the next highest being butanol extract, and ethyl acetate extract being the lowest.
Mutation of the invF Gene Encoding a Salmonella Pathogenicity Island 1 (SPI1) Activator Increases Expression of the SPI2 Gene, sseA
Han, Ah-Reum ; Joe, Min-Ho ; Kim, Dong-Ho ; Baik, Sang-Ho ; Lim, Sang-Yong ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 70~75
DOI : 10.4014/kjmb.1110.10004
In Salmonella enterica, many genes encoded within Salmonella pathogenicity islands (SPI) 1 and 2 are required to cause a range of diseases in a variety of hosts. The SPI1-encoded regulator HilD activates both the SPI1 and 2 genes at different times during growth in Luria-Bertani (LB) media. In this study, the expression levels of hilD during growth in LB were investigated. The data suggest that hilD expression is induced in the early stationary phase and decreases in the late stationary phase, when sseA, an SPI2 gene, is maximally expressed. However, HilD could act as an activator of sseA expression in the late stationary phase despite being present at low levels. SseA expression was investigated in SPI1 regulator mutant strains, hilA, hilD and invF mutants. As expected, hilD mutation decreased sseA expression. However, we found that invF mutation caused a 1.5-fold increase in sseA expression in not only LB but also M9 minimal media, which is thought to resemble an intracellular environment. InvF overexpression restored sseA expression to wild-type levels in an invF mutant but did not cause an additional reduction in sseA expression. These results suggest that SPI1 controls SPI2 expression either positively or negatively.
Characterization of the Bacterial Community in a Biocover for the Removal of Methane, Benzene and Toluene
Ryu, Hee-Wook ; Cho, Kyung-Suk ;
Microbiology and Biotechnology Letters, volume 40, issue 1, 2012, Pages 76~81
DOI : 10.4014/kjmb.1201.01003
Removal of methane, benzene and toluene was evaluated in a lab-scale biocover packed with a soil mixture of forest soil and earthworm cast (75:25 weight ratio). The bacterial community in the biocover was characterized using quantitative real-time PCR and terminal restriction fragment length polymorphism. Methane was removed at the upper layer of the biocover (-0.1 ~ -0.4 m), where the oxygen concentration was remarkably lower. The average removal efficiencies for methane and benzene/toluene were 90% and 99%, respectively. The pmoA gene copy numbers, responsible for methane oxidation, in the upper layer were higher than those in the lower layer. While type I methanotrohs dominated the lower layer, type II methanotrophs, such as Methylocystis and Methylosinus, were noted to be predominant in the upper layer. Benzene and toluene were removed from the lower layer (-0.6 ~ -0.9 m) as well as the upper layer. Moreover, the tmoA gene copy number, responsible for benzene/toluene oxidation, seen in the upper layer was not significantly different from those seen in the lower layer. These results suggest that a biocover packed with a soil and earthworm cast mixture is a promising method which could be utilized for the control of methane and volatile organic compounds such as benzene and toluene.