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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Microbiology and Biotechnology Letters
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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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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Bacterial Quorum Sensing and Quorum Quenching for the Inhibition of Biofilm Formation
Lee, Jung-Kee ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 83~91
DOI : 10.4014/kjmb.1205.05011
Quorum sensing (QS) is a cell-to-cell communication system, which is used by many bacteria to regulate diverse gene expression in response to changes in population density. Bacteria recognize the differences in cell density by sensing the concentration of signal molecules such as N-acyl-homoserine lactones (AHL) and autoinducer-2 (AI-2). In particular, QS plays a key role in biofilm formation, which is a specific bacterial group behavior. Biofilms are dense aggregates of packed microbial communities that grow on surfaces, and are embedded in a self-produced matrix of extracellular polymeric substances (EPS). QS regulates biofilm dispersal as well as the production of EPS. In some bacteria, biofilm formations are regulated by c-di-GMP-mediated signaling as well as QS, thus the two signaling systems are mutually connected. Biofilms are one of the major virulence factors in pathogenic bacteria. In addition, they cause numerous problems in industrial fields, such as the biofouling of pipes, tanks and membrane bioreactors (MBR). Therefore, the interference of QS, referred to as quorum quenching (QQ) has received a great deal of attention. To inhibit biofilm formation, several strategies to disrupt bacterial QS have been reported, and many enzymes which can degrade or modify the signal molecule AHL have been studied. QQ enzymes, such as AHL-lactonase, AHL-acylase, and oxidoreductases may offer great potential for the effective control of biofilm formation and membrane biofouling in the future. This review describes the process of bacterial QS, biofilm formation, and the close relationship between them. Finally, QQ enzymes and their applications for the reduction of biofouling are also discussed.
Expression of Recombinant Hybrid Peptide Gaegurin4 and LL37 using Fusion Protein in E. coli
Bayarbat, Ishvaanjil ; Lee, Jae-Hag ; Lee, Soon-Youl ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 92~97
DOI : 10.4014/kjmb.1203.03004
Antimicrobial peptides (AMPs) are important components of living organisms acting against Gram-negative and Gram-positive bacterial and fungal pathogens. Cathelicidin human peptides have a variety of biological activities that can be used in clinical applications. AMPs are not produced naturally in large quantities, and chemical synthesis is also economically impractical, especially for long peptides. Therefore, as an alternative, heterologous expression of AMPs by recombinant techniques has been studied as a means to reduce production costs. E. coli is an excellent host for the expression of AMPs, as well as other recombinant proteins, because of the low cost involved and its easy manipulation. However, overexpression of AMPs in E. coli has been shown to cause difficulties resulting from the toxicity of the subsequently produced AMPs. Therefore, fusion expression was theorized to be a solution to this problem. In this study, AMPs were expressed as fused proteins with the glutathione S-transferase (GST) binding protein to protect against the toxicity of AMPs when expressed in E. coli. The LL37, and hybrid gaegurin and LL37 (GGN4(1-16)-LL37(17-32), which we designated as GL32, peptides were expressed as GST-fusion proteins in E. coli and the fusion proteins were then purified by affinity columns. The purified peptides were obtained by removal of GST and were confirmed by western blot analysis. The purified antimicrobial peptides then demonstrated antimicrobial activities against Gram-negative and Gram-positive bacterial strains.
The Isolation and Culture Characterization of a Lipolytic Enzyme Producing Strain from Meju
Yun, Hye-Ju ; Lee, You-Jung ; Yeo, Soo-Hwan ; Choi, Hye-Sun ; Park, Hye-Young ; Park, Heui-Dong ; Baek, Seong-Yeol ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 98~103
DOI : 10.4014/kjmb.1205.05010
For screening of useful enzymes producing microorganisms from Meju, we isolated high lipase producing strains and their lipolytic enzyme activities were then tested. The lipolytic enzyme activities of isolated microorganisms were therefore tested on the Y124 strain. The gene sequence analysis of ITS from Y124 strain revealed Yarrowia lipolytica. Lipase production by the Y124 strain was studied in media containing various carbon sources. The Y124 strain drastically increased lipolytic enzyme activity in YPO media containing olive oil, as well as in YPDO media containing both olive oil and glucose. Maximal lipase production was achieved in YPD (yeast extract-peptone-D-glucose) media containing 0.7% olive oil when cultured at
for 8 hrs. The lipase produced from the Y124 strain showed the highest activity in p-NPO (p-nitrophenyl octanoate (
)), amongst the various p-nitrophenyl esters.
Improvement of Transglycosylation Efficiency using a Glycosynthase Mutant derived from Thermoplasma acidophilum
Hwang, Sung-Min ; Seo, Seong-Hwa ; Park, In-Myoung ; Choi, Kyoung-Hwa ; Kim, Do-Man ; Cha, Jae-Ho ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 104~110
DOI : 10.4014/kjmb.1202.02006
Glycosynthase is an active site nucleophile mutant enzyme, prepared from glycosidase, which is capable of synthesizing oligosaccharide derivatives without the hydrolysis of the product. Thermoacidophilic
-glucosidase of Thermoplasma acidophilum (AglA) exhibits a transglycosylating activity yielding various glycosides. AglA was converted to glycosynthase by the substitution of the catalytic nucleophile Asp-408 residue into non-nucleophile glycine in order to increase its ability to synthesize various glycosides by transglycosylation. The glycosynthase mutant was purified by Ni-NTA chromatography and its glycoside-synthesizing activity was measured by using an external nucleophile, sodium formate buffer, providing maltose as a donor and p-nitrophenyl-
) as an acceptor, respectively. In addition,
was examined for its feasibility to act as both a donor and an acceptor, and products were compared with those of the wildtype enzyme. The mutant enzyme was found to catalyze the formation of a specific product from
with a yield of 42.5% without further hydrolysis, while the wild-type enzyme produced two
products at low yields. The results demonstrate the possibility of satisfactory yields for the reactions in the presence of small amounts of acceptor, and demonstrate that the high activity of the mutant, at pHs below neutrality, was applicable in the transfer of glucose from the natural donor.
Changes in Yeast and Bacterial Flora during Fermentation and Storage of Gugija-Liriope tuber Makgeolli using PCR-DGGE
Min, Jin-Hong ; Nam, Yun-Gyu ; Ju, Jung-Il ; Jung, Jae-Hong ; Lee, Jong-Soo ; Kim, Ha-Kun ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 111~116
DOI : 10.4014/kjmb.1202.02004
In this study, we investigated the microbial flora changes in Gugija-Liriope tuber Makgeolli during fermentation and storage periods. We brewed Gugija-Liriope tuber Makgeolli for a week through twostage fermentations and stored the fermentation broth for a month at
. We collected the samples periodically and analyzed microbial flora changes using viable cell counts and PCR-denaturing gradient gel electrophoresis (DGGE). Yeast viable cells were seen to have decreased to 13% of pre-storage levels after storage for 15 days at
; however significant changes were not observed during storage at
. Prolongation of storage time dramatically decreased the availability of viable cells. Yeast viable cell numbers had decreased to 38% of pre-storage levels at
and 4.8% at
after storage for 30 days. The results of the DGGE profile for yeast showed that Saccharomyces cerevisiae and Saccharomyces sp. were the predominant strains at the beginning of fermentation and throughout the whole period of storage. Viable cell counts for total bacteria had decreased to 36% of pre-storage levels after storage for 15 days but did not significantly change for the full 30 days of storage at
. Similarly, viable cell counts for bacteria had decreased to 5% while viable cell numbers did not significantly change for the full 30 days at
. Viable cell counts for lactic acid bacteria were performed and the results were similar to those for total bacteria. The results of the DGGE profile for bacteria showed that Weissella cibaria was the predominant strain at the beginning of fermentation. However it had disappeared by the end of fermentation, and Lactobacillus fermentum and Pediococcus acidilactici became the predominant species during storage.
Cell Biological Function of Secretome of Adipose-Derived Stem Cells on Human Dermal Fibroblasts and Keratinocytes
Lee, Jae-Seol ; Lee, Jong-Hwan ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 117~127
DOI : 10.4014/kjmb.1204.04001
The beneficial effects of adipose-derived stem cell conditioned media (ADSC-CM) for skin regeneration have previously been reported, despite the precise mechanism of how ADSC-CM promotes skin regeneration remaining unclear. ADSC-CM contains various secretomes and this may be a factor in it being a good resource for the treatment of skin conditions. It is also known that ADSC-CM produced in hypoxia conditions, in other words Advanced Adipose-Derived Stem cell Protein Extract (AAPE), has excellent skin regenerative properties. In this study, a human primary skin cell was devised to examine how AAPE affects human dermal fibroblast (HDF) and human keratinocyte (HK), which both play fundamental roles in skin regeneration. The promotion of collagen formation by HDFs was observed at 0.32 mg/ml of AAPE. AAPE treatment significantly stimulated stress fiber formation. DNA gene chips demonstrated that AAPE in HKs (p<0.05) affected the expression of 133 identifiable transcripts, which were associated with cell proliferation, migration, cell adhesion, and response to wounding. Twenty five identified proteins, including MMP, growth factor and cytokines such as CD54, FGF-2, GM-CSF, IL-4, IL-6, VEGF, TGF-
, MMP-1, MMP-10, and MMP-19, were contained in AAPE via antibody arrays. Thus, AAPE might activate the HK biological function and induce the collagen synthesis of HDF. These results demonstrate that AAPE has the potential to be used for clinic applications aimed at skin regeneration.
Organic Matter Analysis and Physicochemical Properties of Leachate from a Foot-and-Mouth Disease Landfill Site
Kang, Mee-A ; Kim, Mi-Sun ; Choi, Byung-Woo ; Sohn, Ho-Yong ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 128~134
DOI : 10.4014/kjmb.1202.02008
Foot and mouth disease (FMD) is one of the most notorious and contagious viral diseases afflicting cloven-hoofed animals. In this study, the physicochemical properties of leachate from a FMD landfill site at 773-1, Waryong, Andong, Korea and the ground water from 777, Waryong, Andong, Korea, were analyzed for 1 year from December
2010 to November
2011. The leachate was collected from the FMD landfill site during March, May, July, September and November, 2011 and changes in pH, brix, water content, insoluble solids, crude proteins, crude lipids, total and reducing sugars and ash content were determined. Considering the annual profiles of temperature and rainfall at the FMD landfill site, the dramatic changes in the physicochemical properties of the leachate from March to July, and especially from May to July, such as increases in pH, and a rapid reduction of brix and organic matter, may be closely linked to the growth of microorganisms in the leachate. The sharp decreases in the concentration of biominerals, such as Mg, Ca, and Fe from 1073, 4311 and 56.2 ppm in March to 151, 78, and 0.1 ppm in November, further suggest that decreases in organic matter in the leachate result from degradation by microorganisms originating from the intestines of the livestock. Analysis of the profiles of the organic materials in the leachate revealed that the properties of the leachate were similar to those of excremental matter-derived water. These results could be applied to a number of fields for the analysis of organic matter behavior, the development of the degradation process, and risk analysis in the environment for hygiene and food industries, of leachate from FMD landfill sites.
Induced of Systemic Resistance against Gray Leaf Spot in Pepper by Enterobacter Species Isolated from Family Gramineae Plants in Dok-do
Son, Jin-Soo ; Sumayo, Marilyn ; Kang, Hyun-Uk ; Kim, Byung-Soo ; Kwon, Duck-Kee ; Ghim, Sa-Youl ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 135~143
DOI : 10.4014/kjmb.1203.03002
This study's aim is to isolate and characterize plant growth promoting Enterobacter species for the biological control of gray leaf spot in pepper. Screening was carried out from the rhizosphere of Agropyron tsukushiensi var. transiens (Hack.) Ohwi in Dok-do. Rhizobacterial isolates were partially identified by 16S rDNA sequencing and Enterobacter species were tested for plant growth promoting capabilities and the induction of systemic resistance in pepper against gray leaf spot caused by Stemphylium solani. Isolates were tested for production of indole-acetic acid and siderophore, and for phosphate solubilization. The application of isolates was effective in controlling gray leaf spot in pepper with E. asburiae (KNUC5007) and E. cancerogenes (KNUC5008 and KNUC5010) having the highest efficacy in reducing gray leaf spot severity. This is the first report of the biological control of gray leaf spot in pepper using rhizobacteria and it is hoped that this study will increase the utilization of Enterobacter species as plant growth promoters and biocontrol agents.
Evaluation of the Antimicrobial Activities of 35 Seaweed Extracts against Pathogenic Bacteria and Candida sp.
Kim, Mi-Sun ; Kwon, Kyung-Jin ; Lee, Min-Jin ; Ahn, Seon-Mi ; Sohn, Ho-Yong ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 144~151
DOI : 10.4014/kjmb.1203.03005
In the course of this study aimed at the development of functional food ingredients from seaweeds, the in vitro antimicrobial activities of methanol extracts prepared from 35 different seaweeds (17 phaeophyta, 11 rhodophyta and 7 chlorophyta) were determined against food-borne diseases and pathogenic microorganisms including multi-drug resistant (MDR) Pseudomonas sp. and Candida sp. Based on disc-diffusion assays at 500 g/disc concentration of the methanol extracts, Ishige okamurai, I. foliacea, Sargassum confusum, and S. yamade exhibited strong antibacterial activities in a broad-spectrum, except against Pseudomonas aeruginosa. In addition to the latter four seaweeds, Ecklonia stolonifera, E. cava and Eisenia bicyclis also demonstrated antifungal activity against C. albicans. Among these 8 selected seaweeds, I. okamurai, I. foliacea, and S. yamade exhibited strong hemolytic activity (55-93%) at 500 g/ml against human RBC. Organic solvent sequential fractions using hexane, ethylacetate and butanol, and water residues were prepared from the 8 selected seaweeds and their anti-Candida sp. activities were further determined. The ethylacetate and butanol fraction of I. okamurai, and the hexane fraction of I. foliacea demonstrated antifungal activity against MDR-pathogenic Candida sp. Although the solvent fractions had no activity against MDR-Pseudomonas sp., our results suggest that seaweeds, especially Ishige okamurai, I. foliacea, S. confusum, and S. yamade could be developed as broad-spectrum antimicrobial ingredients.
Characterization of Methanotrophic Communities in Soils from Regions with Different Environmental Settings
Kim, Tae-Gwan ; Park, Hyun-Jung ; Lee, Sang-Hyon ; Kim, Pyeong-Wha ; Moon, Kyung-Eun ; Cho, Kyung-Suk ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 152~156
DOI : 10.4014/kjmb.1202.02001
Methanotrophic communities from freshwater wetland (FW), seawater wetland (SW), forest (FS), and landfill soils (LS) around Seoul of South Korea, were characterized using comparative sequence analyses of clone libraries. Proportions of Methylocaldum, Methlyococcus and Methylosinus were found to be greater in FW and SW, while Methylobacter and Methylomonas were more notable in FS and Methylocystis and Methylomicrobium more prominent in LS. Lag periods behind the initiation of methane oxidation significantly varied amongst the soils. Methane oxidation rates were greater in
(p<0.05). Thus, the environmental setting is a significant factor influencing the communities and capabilities of methanotrophs.
Decrease in the Particle Size of Paclitaxel by Increased Surface Area Fractional Precipitation
Lee, Ji-Yeon ; Kim, Jin-Hyun ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 157~162
DOI : 10.4014/kjmb.1203.03003
In this study, we have for the first time applied increased surface area fractional precipitation in order to decrease the particle size of the anticancer agent paclitaxel from plant cell cultures. When compared with the case where no surface area increasing material was employed, the addition of ion exchange resin as a surface area increasing material resulted in a considerable decrease in the size of the paclitaxel precipitate. When ion exchange resin was used, the paclitaxel particles were four to five times smaller, having less than a 20
radius, than those obtained in the absence of ion exchange resin. This is presumably because the growth of paclitaxel particles was impeded by the addition of ion exchange resin. The size of the paclitaxel precipitate also depended on the material used to increase the surface area, a result considered to be due to differences in the affinity between the particular ion exchange resin used and the paclitaxel particles. The yield of paclitaxel was significantly improved when ion exchange resin was used as a material to increase surface area. Paclitaxel, with a reduced particle size due to the addition of a surface area increasing material during the fractional precipitation process, is believed to be particularly useful for practical applications of the drug.
Electrostatic Immobilization of D-Xylose Isomerase to a Cation Exchanger for the Conversion of D-Xylose to D-Xylulose
Hang, Nguyen Thi ; Kim, Sung-Gun ; Kweon, Dae-Hyuk ;
Microbiology and Biotechnology Letters, volume 40, issue 2, 2012, Pages 163~167
DOI : 10.4014/kjmb.1205.05028
Since D-xylose is not fermentable in Saccharomyces cerevisiae, its conversion to D-xylulose is required for its application in biotechnological industries using S. cerevisiae. In order to convert D-xylose to D-xylulose by way of an enzyme immobilized system, D-xylose isomerase (XI) of Escherichia coli was fused with 10-arginine tag (R10) at its C-terminus for the simple purification and immobilization process using a cation exchanger. The fusion protein XIR10 was overexpressed in recombinant E. coli and purified to a high purity by a single step of cation exchange chromatography. The purified XIR10 was immobilized to a cation exchanger via the electrostatic interaction with the C-terminal 10-arginine tag. Both the free and immobilized XIR10 exhibited similar XI activities at various pH values and temperatures, indicating that the immobilization to the cation exchanger has a small effect on the enzymatic function of XIR10. Under optimized conditions for the immobilized XIR10, D-xylose was isomerized to D-xylulose with a conversion yield of 25%. Therefore, the results of this study clearly demonstrate that the electrostatic immobilization of XIR10 via the interaction between the 10-arginine tag and a cation exchanger is an applicable form of the conversion of D-xylose to D-xylulose.