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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Microbiology and Biotechnology
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 16, Issue 12 - Dec 2006
Volume 16, Issue 11 - Nov 2006
Volume 16, Issue 10 - Oct 2006
Volume 16, Issue 9 - Sep 2006
Volume 16, Issue 8 - Aug 2006
Volume 16, Issue 7 - Jul 2006
Volume 16, Issue 6 - Jun 2006
Volume 16, Issue 5 - May 2006
Volume 16, Issue 4 - Apr 2006
Volume 16, Issue 3 - Mar 2006
Volume 16, Issue 2 - Feb 2006
Volume 16, Issue 1 - Jan 2006
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Proteomics for Streptomyces: 'Industrial Proteomics' for Antibiotics
Lee Kwang-Won ; Joo Hwang-Soo ; Yang Yung-Hun ; Song Eun-Jung ; Kim Byung-Gee ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 331~348
Antimicrobial Effect of Furaneol Against Human Pathogenic Bacteria and Fungi
Sung Woo-Sang ; Jung Hyun-Jun ; Lee In-Seon ; Kim Hyun-Soo ; Lee Dong-Gun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 349~354
Furaneol, a key aroma compound found in strawberry, pineapple, and processed foodstuffs, has been known to possess various biological activities on animal models. In this study, the antimicrobial effects of furaneol against human pathogenic microorganisms were investigated. The results indicated that furaneol displayed a broad spectrum of antimicrobial activities against Gram-positive and Gram-negative bacteria and fungi without hemolytic activity on human erythrocyte cells. To confirm the antifungal activity of furaneol, we examined the accumulation of intracellular trehalose as a stress response marker on toxic agents and its effect on dimorphic transition of Candida albicans. The results demonstrated that furaneol induced significant accumulation of intracellular trehalose and exerted its antifungal effect by disrupting serum-induced mycelial forms. These results suggest that furaneol could be a therapeutic agent having a broad spectrum of antimicrobial activity on human pathogenic microorganisms.
Enhanced In Vitro Protein Synthesis Through Optimal Design of PCR Primers
Ahn Jin-Ho ; Son Jeong-Mi ; Hwang Mi-Yeon ; Kim Tae-Wan ; Park Chang-Kil ; Choi Cha-Yong ; Kim Dong-Myung ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 355~359
The functional stability of mRNA is one of the crucial factors affecting the efficiency of in vitro translation. As the rapid degradation of mRNA in the cell extract (S30 extract) causes early termination of the translational reactions, extending the mRNA half-life will improve the productivity of the in vitro protein synthesis. Thus, a simple PCR-based method is introduced to increase the stability of mRNA in an S30 extract. The target genes are PCR-amplified with primers designed to make the ends of the transcribed mRNA molecule anneal to each other. When compared with normal mRNA, the mRNA with the annealing sequences resulted in an approximately 2-fold increase of protein synthesis in an in vitro translation reaction. In addition, sequential transcription and translation reactions in a single tube enabled direct protein expression from the PCR-amplified genes without any separate purification of the mRNA.
Inulooligosaccharide Production from Inulin by Saccharomyces cerevisiae Strain Displaying Cell-Surface Endoinulinase
Kim Hyun-Chul ; Kim Hyun-Jin ; Choi Woo-Bong ; Nam Soo-Wan ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 360~367
The endoinulinase gene (inu1) from Pseudomonas mucidolens was expressed on the cell surface of Saccharomyces cerevisiae by fusing with Aga2p linked to the membrane anchored protein, Aga1p. The inu1 gene of P. mucidolens was subcloned into the surface display vector, pCTcon (GAL1 promoter). The constructed plasmid, pCTENIU (8.5kb), was then introduced to S. cerevisiae EBY100 cells and the yeast transformants selected on synthetic defined media lacking uracil and inulin-containing media. The inu1 gene under the control of the GAL1 promoter was successfully expressed in the yeast transformants, and the surface display of endoinulinase confirmed by immunofluorescence microscopy, along with its enzymatic ability to form inulooligosaccharides (IOSs) from inulin. The total endoinulinase activity reached about 2.31 units/ml when the yeast transform ants were cultivated on a YPDG medium. To efficiently hydrolyze the inulin, various reaction conditions were examined, including the pH, temperature, and inulin source. The optimized conditions were then determined as follows: pH, 7.0; temperature,
; inulin source, Jerusalem artichoke. Under the optimized condition and 46 units of endoinulinase per g of inulin, IOSs started to be produced after 10 min of enzymatic reaction. The highest yield, 71.2% of IOSs, was achieved after 30 h of reaction without any significant loss of the initial enzyme activity. As a result of the reaction with inulin, IOSs consisting of inulobiose (F2), inulotriose (F3), inulotetraose (F4), and inulopentaose (F5) were produced, and F4 was the major product.
Proteome Analysis of Bacillus subtilis When Overproducing Secretory Protein
Jang Mi ; Park Byoung-Chul ; Lee Do-Hee ; Kho Chang-Won ; Cho Sa-Yeon ; Lee Baek-Rak ; Park Sung-Goo ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 368~373
Bacillus subtilis and related Bacillus species are frequently used as hosts for the mass production of recombinant proteins. Accordingly, this study examined the cellular response of B. subtilis to the overexpression of a soluble secretory protein. As such, the lichenase derived from B. cereus was overexpressed in B. subtilis, initially localized in the cytoplasm as a mature form and then secreted into the medium. Thereafter, the proteome of B. subtilis was analyzed using 2D electrophoresis and MALDI-TOF mass spectrometry. The expression of several heat-shock proteins, such as dnaK and groEL, was increased under this condition. In addition, manganese superoxide dismutase and NADH dehydrogenase were also upregulated in the lichenase-secreting B. subtilis. Therefore, it was concluded that the transient accumulation of a secreted protein in B. subtilis before secretion acted as a stress on the cell, which in turn induced the expression of various protective proteins.
Continuous Production of Pullulan by Aureobasidium pullulans HP-2001 with Feeding of High Concentration of Sucrose
Seo Hyung-Phil ; Jo Kang-Ik ; Son Chang-Woo ; Yang Jae-Kyoon ; Chung Chung-Han ; Nam Soo-Wan ; Kim Sung-Koo ; Lee Jin-Woo ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 374~380
In this study, glucose, sucrose, and dextrin were found to be better carbon sources for the production of pullulan by Aureobasidium pullulans HP-2001. Maximal production of pullulan with 200 g/l sucrose as a carbon source was 54.2 g/l. The highest yield of pullulan from sucrose was 0.40, when the sugar concentration was 100 g/1. Optimal conditions for the continuous production of pullulan by A. pullulans HP-2001 in a 7-1 bioreactor were determined by studying the effects of composition of feed solution, dilution rate, and concentration of sucrose in the feed solution. Pullulan concentration and productivity with 100 g/l glucose and 2.5 g/l yeast extract were 38.1 g/l and 0.53 g/l h for 72 h, respectively, in a batch culture of A. pullulans HP-2001. When the substituted medium contained 100 g/l sucrose, 2.5 g/l yeast extract, and mineral salts, which is the same composition as the medium for the production of pullulan, the pullulan concentration and productivity were 74.9 g/l and 0.55 g/l h for 120 h, respectively. The production of pullulan at the steady state increased with a dilution rate up to 0.015/h, and its concentration was 78.4 g/l with a weight average molecular weight (
. Unlike a batch culture, however, the decline of the
and the number average molecular weight (
) of pullulan was not found in the continuous culture of A. pullulans HP-2001. When the concentration of sucrose in the feed solution was 200 g/l, 113.5 g/l of pullulan was obtained at the steady state. The steady state was maintained longer in the continuous culture fed with the feed solution containing 200 g/l sucrose than when fed with the feed solutions containing either 100 or 150 g/l sucrose.
High-Level Production of Astaxanthin by Xanthophyllomyces dendrorhous Mutant JH1, Using Chemical and Light Induction
Kim Jeong-Hwan ; Chang Hyo-Ihl ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 381~385
The production of astaxanthin by Xanthophyllomyces dendrorhous mutant depended on the culture conditions. Therefore, a cultivation strategy, including effective chemical and light induction, for the high-level production of astaxanthin by X. dendrorhous mutant JH1 was explored. Effective chemicals such as ethanol, acetic acid, and hydrogen peroxide, which are known inducers or precursors of astaxanthin synthesis, were investigated for their increase of astaxanthin production. Each of 1.0% ethanol, 1.0% acetic acid, and 1.0% hydrogen peroxide increased the astaxanthin concentration to 49.77 mg/l, 46.33 mg/l, and 45.61 mg/l, respectively. Among these chemicals, 1.0% ethanol showed the best effect on increasing astaxanthin concentration after 48 h of cultivation. Under 1.0% ethanol feeding condition, high light intensity (2,400 lux) stimulated astaxanthin production to 59.67 mg/l, compared with that in the dark-grown cultivation.
Construction of a Reporter Strain Pseudomonas putida for the Detection of Oxidative Stress Caused by Environmental Pollutants
Lee Yun-Ho ; Ahn Eun-Young ; Park Sung-Su ; Madsen Eugene L. ; Jeon Che-Ok ; Park Woo-Jun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 386~390
A green fluorescent protein-based Pseudomonas putida reporter was successfully constructed and shown to be capable of detecting oxidative stress. In this whole-cell reporter, the promoter of the paraquat-inducible ferredoxin-
reductase (fpr) was fused to a promoterless gfp gene on a broad-host-range promoter probe vector. Pseudomonas putida KT2440 harboring this reporter plasmid exhibited an increased level of gfp expression in the presence of redox-cycling agents (paraquat and menadione), hydrogen peroxide, and potential environmental pollutant chemicals such as toluene, paint thinner, gasoline, and diesel. Induction of fpr in the presence of these chemicals was confirmed using Northern blot analysis.
Role of PI3-Kinase/Akt Pathway in the Activation of Etoposide-Induced
Choi Yong-Seok ; Park Heon-Yong ; Jeong Sun-Joo ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 391~398
is a transcription factor involved in the innate immunity against bacterial infection and inflammation. It is also known to render cells resistant to the apoptosis caused by some anticancer drugs. Such a chemoresistance of cancer cells may be related to the activation of
transcription factor; however, the mechanism of activation is not well understood. Here, we demonstrate that a chemotherapeutic agent, etoposide, independently stimulates the
degradation pathway and PI3-kinase/Akt signaling pathway: The classical
degradation pathway leads to the nuclear translocation and DNA binding of p65 subunit through
kinase, whereas the PI3-kinase/Akt pathway plays a distinct role in activating this transcription factor. The PI3-kinase/Akt pathway acts on the p50 subunit of the
transcription factor and enhances the DNA binding affinity of the p50 protein. It may also explain the role of the PI3-kinase/Akt pathway in the anti-apoptotic function of
during chemoresistance of cancer cells.
Effect of Electrochemical Oxidation Potential on Biofilter for Bacteriological Oxidation of VOCs to
Kang Hye-Sun ; Lee Jong-Kwang ; Kim Moo-Hoon ; Park Doo-Hyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 399~407
In this study, an electrical conductive carbon fiber was used as a biofilter matrix to electrochemically improve the biofilter function. A bioreactor system was composed of carbon fiber (anode), titanium ring, porcelain ring, inorganic nutrient reservoir, and VOC reservoir. Electric DC power of 1.5 volt was charged to the carbon fiber anode (CFA) to induce the electrochemical oxidation potential on the biofilter matrix, but not to the carbon fiber (CF). We tested the effects of electrochemical oxidation potential charged to the CFA on the biofilm structure, the bacterial growth, and the activity for metabolic oxidation of VOCs to
, According to the SEM image, the biofilm structure developed in the CFA appeared to be greatly different from that in the CF. The bacterial growth, VOCs degradation, and metabolic oxidation of VOCs to
in the CFA were more activated than those in the CF. On the basis of these results, we propose that the biofilm structure can be improved, and the bacterial growth and the bacterial oxidation activity of VOCs can be activated by the electrochemical oxidation potential charged to a biofilter matrix.
Gene Cloning of Streptomyces Phospholipase D P821 Suitable for Synthesis of Phosphatidylserine
Moon Min-Woo ; Lee Jung-Kee ; Oh Tae-Kwang ; Shin Chul-Soo ; Kim Hyung-Kwoun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 408~413
A strain, P821, with phospholipase D activity was isolated from soil and identified as a Streptomyces species. The phospholipase D enzyme was purified from a culture broth of the isolated strain using ammonium sulfate precipitation and DEAE-Sepharose, phenyl-Sepharose, and Superose 12 HR column chromatographies. The purified enzyme exhibited an optimum temperature and pH of
and 6.0, respectively, in the hydrolysis of phosphatidylcholine and remained stable up to
within a pH range of 3.5-8.0. The enzyme also catalyzed a transphosphatidylation reaction to produce phosphatidylserine with phosphatidylcholine and serine substrates. The optimum conditions for the transphosphatidylation were
and pH 5.0, indicating quite different optimum conditions for the hydrolysis and transphosphatidylation reactions. The gene encoding the enzyme was cloned by Southern hybridization and colony hybridization using a DNA probe designed from the conserved regions of other known phospholipase D enzymes. The resulting amino acid sequence was most similar to that of the PLD enzyme from Streptomyces halstedii (89.5%). Therefore, the enzyme was confirmed to be a phospholipase D with potential use in the production of phosphatidylserine.
Characteristics of Immobilized PVA Beads in Nitrate Removal
Cho Kyoung-Sook ; Park Kyoung-Joo ; Jeong Hyun-Do ; Nam Soo-Wan ; Lee Sang-Joon ; Park Tae-Joo ; Kim Joong-Kyun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 414~422
Before applying PVA bio-beads to practical biological treatment of nitrate-containing wastewater, their characteristics were examined. PVA bio-beads could steadily produce nitrogen gas from nitrate for 28 batches with 0.04 ml/l/h of the maximum gas production rate; however, the maximum gas production rate dropped remarkably thereafter with apparent deformation of beads. Addition of 2.2% solution containing 1% casamino acid, 1% yeast extract, 0.1% mineral solution, and 0.1% vitamin solution to the culture medium resulted in not only recovery of activity of deactivated beads, but also a higher rate of gas production. Calculation of economic benefit for the use of bio-beads in a long-run operation indicated that reactivation of bio-beads by chemicals had economical advantages over packing new bio-beads in the system. The continuously stirred bioreactor exhibited a satisfactory performance at HRT of 20.0 h. With a 9.5 mg
nitrate removal rate, nitrate could completely be removed without nitrite accumulation. The use of PVA bio-beads in nitrate removal appears very promising.
Analysis of Genetic Diversity of Phytophthora infestans in Korea by Using Molecular Markers
Zhang Xuan-Zhe ; Kim Hwa-Yeong ; Kim Byung-Sup ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 423~430
A total of 367 isolates of Phytophthora infestans was collected from the leaf samples of late blight disease from five provinces in Korea over the three growing seasons of 2002-2004. Of the 367 isolates, 337 isolates were of the A1 mating type, and 30 isolates were of A2 mating type, showing that the majority was A1 mating type. Profiles of Gpi and Pep defined four allozyme genotypes among the total of 367 isolates. All four allozyme genotypes could be distinguished on the basis of Gpi profiles alone, whereas all isolates were homozygous at the Pep locus (100/100). The mitochondrial DNA haplotype of all isolates were the IIa haplotype. Amplification of the genomic DNAs extracted from eight isolates of each mating type by polymerase chain reaction with the selected primer (OPC-5 primer) produced a total of 20 DNA bands, of which 11 bands were polymorphic. According to the RAPD analysis using the OPC-5 primer, 106 isolates including two standard isolates were separated into 8 groups at the similarity level of 92.5%. The RAPD groups were not correlated with the allozyme genotypes and the isolated locations. All of the eight RAPD groups were identified in Gangwon-do, suggesting that Gangwon-do is the center of origin of the P. infestans in Korea. A 600-bp DNA band generated with the OPC-5 primer was specific to A1 mating type isolates, but not detected with A2 mating type, showing that the specific PCR primer can distinguish different mating types in P. infestans.
Preparation of Kimchi Containing Bifidobacterim animalis DY-64
Chae Myoung-Hee ; Jhon Deok-Young ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 431~437
Aero-tolerant microorganisms were isolated from healthy Koreans over the age of 95 years. The microorganisms were then identified based on their morphological and biochemical characteristics and 16S rDNA sequences. The growth properties of the isolated strains were investigated in kimchi. The characteristics of kimchi containing the microorganisms were studied microscopically, physicochemically, and organoleptically. Among 7 aero-tolerant strains, a strain with a 16S rDNA sequence exhibiting 99% homology with Bifidobacterim animalis strain B83 was selected and named B. animalis DY-64. The new strain showed a better acid resistance and salt resistance (p<0.05) than B. animalis ATCC 25527. After 15 days of fermentation in kimchi, the viability of B. animalis DY-64 was about 10%, and the kimchi had a better overall edible quality than conventional kimchi. Thus, it was found that the application of B. animalis DY-64 to kimchi preparation produced a good overall edible quality.
Effect of Culture Conditions on Astaxanthin Formation in Red Yeast Xanthophyllomyces dendrorhous Mutant JH1
Kim Jeong-Hwan ; Choi Seok-Keun ; Park Young-Sam ; Yun Cheol-Won ; Cho Won-Dai ; Chee Kew-Mahn ; Chang Hyo-Ihl ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 438~442
The formation of astaxanthin by Xanthophyllomyces dendrorhous mutant JH1 depends on the culture conditions. Therefore, the effects of inoculation rate (1-5%, v/v) and medium compositions (various carbon and nitrogen sources) on cell growth and astaxanthin formation in X. dendrorhous mutant JH1 were investigated. Inoculation at 3% (v/v) was optimal for cell growth and astaxanthin formation. The most effective carbon source for cell growth and astaxanthin formation was glucose, and the best nitrogen source was yeast extract. The 3% (w/v) glucose and 0.2% (w/v) yeast extract showed the best effect on cell growth and astaxanthin formation, compared with others tested. The 3% glucose, 0.2% yeast extract,
were selected for cell growth and astaxanthin formation. Under the conditions selected, the maximum concentrations of cell and astaxanthin obtained after 168 h of cultivation were 5.43 g/l and 28.20 mg/l, respectively.
Encapsulation of Bacillus polyfermenticus SCD with Alginate-Methylcellulose and Evaluation of Survival in Artificial Conditions of Large Intestine
Kim Cheon-Jei ; Jun Song-Ae ; Lee Na-Kyoung ; Kim Kee-Tae ; Lee Si-Kyung ; Kim Chang-Han ; Paik Hyun-Dong ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 443~449
Bacillus polyfermenticus SCD was studied for its increasing stability by encapsulation, using 2, 3, and 4% sodium alginate. In these cases, 3% alginate resulted in the maximum survival of B. polyfermenticus SCD in artificial gastric juice for 3 h. Effects of several biopolymers on the encapsulated B. polyfermenticus SCD by 3% sodium alginate were investigated. Encapsulation with 0.5% methylcellulose showed the highest survival rate for 3 h in artificial gastric juice. Therefore, the optimized encapsulation material was 3% alginate with 0.5% methylcellulose. Furthermore, the survival of encapsulated B. polyfermenticus SCD was shown to be 122%, when 1% bile salt was added. Freeze-dried encapsulation resulted in lower survival than with non-dried encapsulation. Therefore, encapsulation was the most effective when 3% sodium alginate was used with 0.5% methylcellulose, but without freeze-drying.
Molecular Characterization of Biosynthetic Genes of an Antifungal Compound Produced by Pseudomonas fluorescens MC07
Kim Jin-Woo ; Kim Eun-Ha ; Kang Yong-Sung ; Choi Ok-Hee ; Park Chang-Seuk ; Hwang In-Gyu ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 450~456
Pseudomonas fluorescens MC07 is a growth-promoting rhizobacterium that suppresses mycelial growth in fungi such as Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici. To determine the role of the bacterium's antifungal activity in disease suppression, we screened 2,500 colonies generated by Tn5lacZ insertions, and isolated a mutant 157 that had lost antifungal activity. The EcoRI fragment carrying Tn5lacZ was cloned into pBluescript II SK(+) and used as a probe to isolate wild-type clones from a genomic library of the parent strain, MC07. Two overlapping cosmid clones, pEH4 and pEH5, that had hybridized with the mutant clone were isolated. pEH4 conferred antifungal activity to the heterologous host P.fluorescens strain 1855.344, whereas pEH5 did not. Through transposon mutagenesis of pEH4 and complementation analyses, we delineated the 14.7-kb DNA region that is responsible for the biosynthesis of an antifungal compound. DNA sequence analysis of the region identified 11 possible open reading frames (ORF), ORF1 through ORF11. A BLAST search of each putative protein implied that the proteins may be involved in an antifungal activity similar to polyketides.
Identification of Three Extracellular Proteases from Bacillus subtilis KCTC 3014
Choi Nack-Shick ; Chung Dong-Min ; Ryu Chung-Hun ; Yoon Kab-Seog ; Maeng Pil-Jae ; Kim Seung-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 457~464
Three extracellular proteases (Vpr, peptidase T, and subtilisin) were identified from the culture supernatant of Bacillus subtilis KCTC 3014. All the proteins were partially purified as a mature form by using a DEAE-cellulose ion-exchange column chromatography. Their activities were determined by using zymography and densitometry. The relative molecular masses of Vpr and peptidase T (PepT) were determined to be 68 and 48 kDa by SDS-PAGE and zymography, respectively. However, subtilisin formed a 'binding mode' at the top of the separating gel. After denaturation by boiling at
for 5 min, its molecular mass was determined to be 29 kDa, whereas its activity was lost. The optimal pH of Vpr, PepT, and subtilisin were 9.0, 6.0-7.0, and 7.0-8.0, respectively. The optimal temperature of Vpr, PepT, and subtilisin was 40, 50, and
, respectively. Inhibitor test revealed that Vpr and subtilisin were serine proteases and that PepT was a metalloprotease. Interestingly, we found that Vpr showed no enzyme activity on a 2DE zymogram gel. Three genes, vpr, pepT, and apr (encoding subtilisin protein), were cloned and their nucleotide and deduced amino acid sequences were determined.
An Antifungal Property of Burkholderia ambifaria Against Phytopathogenic Fungi
Lee Chul-Hoon ; Kim Min-Woo ; Kim Hye-Sook ; Ahn Joong-Hoon ; Yi Yong-Sub ; Kang Kyung-Rae ; Yoon Young-Dae ; Choi Gyung-Ja ; Cho Kwang-Yun ; Lim Yoong-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 465~468
Even though many pesticides are known for barley powdery mildew and wheat leaf rust, alternative controls are necessary, because of consumer rejection of chemical pesticides and the appearance of fungi resistant to fungicides. To discover biopesticides, many broths of microorganisms were screened. Of those, a culture broth of Burkholderia ambifaria showed an excellent antifungal activity against both Erysiphe graminis and Puccinia recondita, which cause barley powdery mildew and wheat leaf rust, respectively.
Study on Operational Factors in a Nitrite-Accumulating Submerged Membrane Bioreactor
Yoo Ik-Keun ; Lim Kyoung-Jo ; Lee Won-Sik ; Kim Dong-Jin ; Cha Gi-Cheol ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 469~474
Partial nitrification blocking of the oxidation of nitrite (
) to nitrate (
) has cost-efficient advantages such as lower oxygen and organics demand for nitrification and denitrification, respectively. A nitrifying membrane bioreactor of submerged type was operated for the treatment of synthetic ammonium wastewater with the purpose of nitrite build-up without affecting the efficiency of ammonium oxidation. A high ammonium concentration (1,000 mg/l) was completely converted to nitrate at up to 2 kg
day under sufficient aeration. The control of pH under sufficient aeration was not a reliable strategy to maintain stable nitrite build-up. When the dissolved oxygen concentration was kept at 0.2-0.4 mg/l by adjusting the aeration rate, about 70% of nitrite content was obtained with ammonium oxidation efficiency higher than 93%. The increase of suction pressure due to membrane fouling was not significant under lowered aerating environment over a 6-month period of operation. The composition of nitrifier community, including relative abundance of nitrite oxidizers in a nitrite-accumulating condition, was quantified by fluorescence in situ hybridization analysis.
Gentisyl Alcohol, an Antioxidant from Microbial Metabolite, Induces Angiogenesis In Vitro
Kim Hye-Jin ; Kim Jin-Hee ; Lee Choong-Hwan ; Kwon Ho-Jeong ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 475~479
Gentisyl alcohol isolated from Penicillium sp. has an antioxidative activity, protecting cells from oxidative stresses. From our in vitro angiogenesis assays with bovine aortic endothelial cells (BAECs), gentisyl alcohol was newly identified as a pro-angiogenic small molecule that induces new blood vessel formation of the cells. Gentisyl alcohol stimulated the proliferation of BAECs in a dose-dependent manner. Moreover, it induced in vitro angiogenesis of BAECs such as invasiveness, migration, and tube formation of the endothelial cells. Effects of gentisyl alcohol on invasion and tube formation were also dose-dependent. These results demonstrate that gentisyl alcohol could affect the angiogenic phenotypes of endothelial cells and be developed as a new small molecule with pro-angiogenic activity.
Exposure Assessment of Ethyl Carbamate in Alcoholic Beverages
Ha Mi-Sun ; Kwon Ki-Sung ; Kim Mee-Hye ; Park Hee-Ra ; Hu Soo-Jung ; Lee Hyo-Min ; Kim Kyung-Mi ; Ko Eun-Jung ; Ha Sang-Do ; Bae Dong-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 480~483
Ethyl carbamate, a by-product produced naturally during fermentation and contained in fermented foods and beverages, is a carcinogen. Thus, due to the high consumption of alcoholic beverages in Korea, the ethyl carbamate concentrations in popular alcoholic beverages were determined, and the daily intake of ethyl carbamate through alcoholic beverages was estimated. The major Korean alcoholic beverages, Soju, beer, and Takju, with the highest market share were sampled and their ethyl carbamate concentrations determined by GC/MS/SIM. The ranges of ethyl carbamate contained in Soju, beer, and Takju was 0.83-10.07, 0.45-0.77, and 0.40-0.93 ppb, respectively. These results and data on the average daily intake of alcoholic beverages were then used to calculate the average and maximum estimated daily intakes (EDI) of ethyl carbamate through alcoholic beverages. As a result, a relatively high EDI of ethyl carbamate through alcoholic beverages was found for Korean males over 30 years old, indicating the need to reduce the ethyl carbamate content in alcoholic beverages.
Potential Suppression of Dental Caries by Maltosyl-Mannitol Produced by Bacillus stearothermophilus Maltogenic Amylase
Cho Kil-Soon ; Shin Sang-Ick ; Cheong Jong-Joo ; Park Kwan-Hwa ; Moon Tae-Wha ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 484~486
Maltosyl (G2)-mannitol, produced by the transglycosylation of mannitol with maltotriose by Bacillus stearothermophilus maltogenic amylase, was not found to support lactic acid production by Streptococcus sobrinus NRRL 14555. Furthermore, the synthesis of water-insoluble glucans from maltosyl-mannitol by S. sobrinus NRRL 14555 was much lower than that from xylitol or mannitol. Consequently, these results suggest that maltosyl-mannitol could be used as a noncariogenic sugar substitute in food products.
Antifungal Activity of Bacillus sp. Against Phytophthora infestans
Kim Hye-Sook ; Yi Yong-Sub ; Choi Gyung-Ja ; Cho Kwang-Yun ; Lim Yoong-Ho ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 487~490
Because of consumer rejection of chemical pesticides and the appearance of microorganisms that are resistant to fungicides, we tried to discover biopesticides. Of 13 microorganisms isolated from Shrimp-jeotkal, a Bacillus sp. showed strong activity against tomato late blight caused by Phytophthora infestans. Its activity was tested both in vivo and in vitro. The identification of the strain was carried out based on 16S rDNA analysis and the morphology by scanning electron microscopy.
In Vivo Antifungal Activities of 67 Plant Fruit Extracts Against Six Plant Pathogenic Fungi
Choi Gyung-Ja ; Kim Jin-Cheol ; Jang Kyoung-Soo ; Lim He-Kyoung ; Park Il-Kwon ; Shin Sang-Chul ; Cho Kwang-Yun ;
Journal of Microbiology and Biotechnology, volume 16, issue 3, 2006, Pages 491~495
Methanol extracts of fruits of 67 plants were screened for in vivo antifungal activity against Magnaporthe grisea, Corticium sasaki, Botrytis cinerea, Phytophthora infestans, Puccinia recondita, and Blumeria graminis f. sp. hordei. Among them, 13 plant extracts (
) showed more than 90% disease-control efficacy against at least one of six plant diseases. Specifically, the extracts of Aleurites fordii, Angelica dahurica, Camellia japonica, Chamaecyparis pisifera, Pittosporum tobira, and Styrax japonica controlled more than 90% of the development of rice blast at
. Extracts of both S. japonica and A. dahurica fruits at
concentration displayed strong antifungal activity against M. grisea on rice seedlings.