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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 17, Issue 12 - Dec 2007
Volume 17, Issue 11 - Nov 2007
Volume 17, Issue 10 - Oct 2007
Volume 17, Issue 9 - Sep 2007
Volume 17, Issue 8 - Aug 2007
Volume 17, Issue 7 - Jul 2007
Volume 17, Issue 6 - Jun 2007
Volume 17, Issue 5 - May 2007
Volume 17, Issue 4 - Apr 2007
Volume 17, Issue 3 - Mar 2007
Volume 17, Issue 2 - Feb 2007
Volume 17, Issue 1 - Jan 2007
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Oxygenase-Based Whole-Cell Biocatalysis in Organic Synthesis
Park, Jin-Byung ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 379~392
Agricultural Fertilizers as Economical Alternative for Cultivation of Haematococcus pluvialis
Dalay Meltem Conk ; Imamoglu Esra ; Demirel Zeliha ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 393~397
A Haematococcus pluvialis strain isolated from the ruins of Ephesus in Turkey was investigated as regards its adaptation to laboratory conditions and maximum growth rate. In the first stage of the experiment, the growth of H. pluvialis was compared in common culture media. Furthermore, in an effort to minimize the culture costs, the second stage of the experiment compared the growth rate in the culture medium selected in the first stage with that in commercial plant fertilizers. The results demonstrated that the maximum cell concentration of 0.90 g/l, corresponding to a growth rate of
, was found with an N-P-K 20:20:20 fertilizer under a light intensity of
day of cultivation.
Effect of a 20 kHz Sawtooth Magnetic Field Exposure on the Estrous Cycle in Mice
Jung, Kyung-Ah ; Ahn, Hae-Sun ; Lee, Yun-Sil ; Gye, Myung-Chan ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 398~402
Abstract Female mice post weaning were exposed to 20 kHz sawtooth electric and magnetic fields (EMF) with
peak intensity for 6 weeks. Estrous cycles were checked using vaginal smears over the last 10 days of the experimental period. The vaginal smears from EMF-exposed mice revealed an increase in the frequency of one or two phases persisting. The number of estrous cycles less than 1 was more in the EMF-exposed group than in the sham control group. Furthermore, in the EMF-exposed group, the duration of proestrous and metestrous stages of the estrous cycle was significantly increased compared with the control group. In conclusion, our results suggest that exposure to 20 kHz sawtooth EMF may affect normal cycling of the estrous cycle by disrupting the female reproductive endocrine physiology. We should not disregard the possible adverse reproductive effect of the 20 kHz sawtooth EMF generated under the occupational exposure situation in females.
Biosynthesis of Bile Acids in a Variety of Marine Bacterial Taxa
Kim, Doc-Kyu ; Lee, Jong-Suk ; Kim, Ji-Young ; Kang, So-Jung ; Yoon, Jung-Hoon ; Kim, Won-Gon ; Lee, Choong-Hwan ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 403~407
Several marine. bacterial strains, which were isolated from seawater off the island Dokdo, Korea, were screened to find new bioactive compounds such as antibiotics. Among them, Donghaeana dokdonensis strain DSW-6 was found to produce antibacterial agents, and the agents were then purified and analyzed by LC-MS/MS and 1D- and 2D-NMR spectrometries. The bioactive compounds were successfully identified as cholic acid and glycine-conjugated glycocholic acid, the
-dehydroxylated derivatives (deoxycholic acid and glycodeoxycholic acid) of which were also detected in relatively small amounts. Other marine isolates, taxonomically different from DSW-6, were also able to produce the compounds in a quite different production ratio from DSW-6. As far as we are aware of, these bile acids are produced by specific members of the genus Streptomyces and Myroides, and thought to be general secondary metabolites produced by a variety of bacterial taxa that are widely distributed in the sea.
Gene Cloning, Expression, and Functional Characterization of an Ornithine Decarboxylase Protein from Serratia liquefaciens IFI65
De Las Rivas Blanca ; Carrascosa Alfonso V. ; Munoz Rosario ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 408~413
Putrescine has a negative effect on health and is also used as an indicator of quality on meat products. We investigated the genes involved in putrescine production by Serratia liquefaciens IFI65 isolated from a spoiled Spanish dry-cured ham. We report here the genetic organization of its ornithine decarboxylase encoding region. The 5,506-bp DNA region showed the presence of three complete and two partial open reading frames. Putative functions have been assigned to several gene products by sequence comparison with proteins included in the databases. The second gene putatively coded for an ornithine decarboxylase. The functionality of this decarboxylase has been experimentally demonstrated by complementation to an E. coli defective mutant. Based on sequence comparisons of some enterobacterial ornithine decarboxylase regions, we have elaborated a hypothetical pathway for the acquisition of putrescine biosynthetic genes in some Enterobacteriaceae strains.
on Growth and Hydrocarbon Production in Botryococcus braunii
Ranga Rao, A. ; Sarada R. ; Ravishankar G.A. ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 414~419
Botryococcus braunii is a green colonial fresh water microalga and it is recognized as one of the renewable resources for production of liquid hydrocarbons. CFTRI-Bb-l and CFTRI-Bb-2 have been reported for the first time and their performance with regard to growth and biochemical profile is presented here. The present study focused on effect of carbon dioxide
on biomass, hydrocarbon, carbohydrate production, fatty acid profile, and carotenoid content in various species of B. braunii (LB-572, SAG 30.81, MCRC-Bb, N-836, CFTRI-Bb-l, and CFTRI-Bb-2) at 0.5, 1.0, and 2.0% (v/v) levels using a two-tier flask.
at 2.0% (v/v) level enhanced growth of the organism, and a two-fold increase in biomass and carotenoid contents was observed in all the B. braunii strains studied compared with control culture (without
supplementation). At 1 % and 2% (v/v)
concentrations, palmitic acid and oleic acid levels increased by 2.5 to 3 folds in one of the strains of B. braunii (LB-572). Hydrocarbon content was found to be above 20% at 2%
level in the B. braunii LB-572, CFTRI-Bb-2, CFTRI-Bb-l, and N-836 strains, whereas it was less than 20% in the SAG 30.81 and MCRC-Bb strains compared with control culture. This culture methodology will provide information on
requirement for growth of algae and metabolite production. B. braunii spp. can be grown at the tested levels of
concentration without much influence on culture pH.
Temperature Effects on Korean Entomopathogenic Nematodes, Steinernema glaseri and S. longicaudum, and their Symbiotic Bacteria
Hang Dao Thi ; Choo, Ho-Yul ; Lee, Dong-Woon ; Lee, Sang-Myeong ; Kaya Harry K. ; Park, Chung-Gyoo ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 420~427
We investigated the temperature effects on the virulence, development, reproduction, and otility of two Korean isolates of entomopathogenic nematodes, Steinernema glaseri Dongrae strain and S. longicaudum Nonsan strain. In addition, we studied the growth and virulence of their respective symbiotic bacterium, Xenorhabdus poinarii for S. glaseri and Xenorhabdus sp. for S. longicaudum, in an insect host at different temperatures. Insects infected with the nematode-bacterium complex or the symbiotic bacterium was placed at
in the dark and the various parameters were monitored. Both nematode species caused mortality at all temperatures tested, with higher mortalities occurring at temperatures between
. However, S. longicaudum was better adapted to cold temperatures and caused higher mortality at
than S. glaseri. Both nematode species developed to adult at all temperatures, but no progeny production occurred at
. For S. glaseri, nematode progeny production was best at inocula levels above 20 infective juveniles/host at
, but for S. longicaudum, progeny production was generally better at
. Steinernema glaseri showed the greatest motility at
, whereas S. longicaudum showed good motility at
. Both bacterial species grew at all tested temperatures, but Xenorhabdus sp. was more virulent at low temperatures
than X. poinarii.
Humic Substances Act as Electron Acceptor and Redox Mediator for Microbial Dissimilatory Azoreduction by Shewanella decolorationis S12
Hong, Yi-Guo ; Guo, Jun ; Xu, Zhi-Cheng ; Xu, Mei-Ying ; Sun, Guo-Ping ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 428~437
The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or
. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.
Biological Control of Strawberry Gray Mold Caused by Botrytis cinerea Using Bacillus licheniformis N1 Formulation
Kim, Hyun-Ju ; Lee, Soo-Hee ; Kim, Choul-Sung ; Lim, Eun-Kyung ; Choi, Ki-Hyuck ; Kong, Hyun-Gi ; Kim, Dae-Wook ; Lee, Seon-Woo ; Moon, Byung-Ju ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 438~444
Bacillus licheniformis N1 is a biological control agent to control gray mold diseases caused by Botrytis cinerea. Various formulations of B. licheniformis N1 were generated and evaluated for the activity to control strawberry gray mold. The wettable powder type formulation N1E was selected in pot experiments with remarkable disease control activity on both strawberry leaves and flowers. The N1E formulation contained 400 g of com starch, 50 ml of olive oil, and 50 g of sucrose per a liter of bacterial fermentation culture. Optimum dilution of N1E to appropriately control the strawberry gray mold appeared to be 100-fold dilution in plastic house artificial infection experiments. The significant reduction of symptom development in the senescent leaves was apparent by the treatment of N1E at 100-fold dilution when N1E was applied before Bo. cinerea inoculation, but not after the inoculation. Both artificial infection experiments in a plastic house and natural infection experiments in the farm plastic house under production conditions revealed that the disease severity of gray mold on strawberry leaves and flowers was significantly reduced by N1E treatment. The disease control value of N1E on strawberry leaves was 81% under production conditions, as compared with the 61.5% conferred by a chemical fungicide, iprodione. This study suggests that our previously generated formulation of B. licheniformis N1 will be effective to control strawberry gray mold by its preventive activity.
Effect of Electrochemical Redox Reaction on Growth and Metabolism of Saccharomyces cerevisiae as an Environmental Factor
Na, Byung-Kwan ; Hwang, Tae-Sik ; Lee, Sung-Hun ; Ahn, Dae-Hee ; Park, Doo-Hyun ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 445~453
The effect of an electrochemically generated oxidation-reduction potential and electric pulse on ethanol production and growth of Saccharomyces cerevisiae ATCC 26603 was experimented and compared with effects of electron mediators (neutral red, benzyl viologen, and thionine), chemical oxidants (hydrogen peroxide and hypochlorite), chemical reductants (sulfite and nitrite), oxygen, and hydrogen. The oxidation (anodic) and reduction (cathodic) potential and electric pulse activated ethanol production and growth, and changed the total soluble protein pattern of the test strain. Neutral red electrochemically reduced activated ethanol production and growth of the test strain, but benzyl viologen and thionine did not. Nitrite inhibited ethanol production but did not influence growth of the test strain. Hydrogen peroxide, hypochlorite, and sulfite did not influence ethanol production and growth of the test strain. Hydrogen and oxygen also did not influence the growth and ethanol production. It shows that the test strain may perceive electrochemically generated oxidation-reduction potential and electric pulse as an environmental factor.
Enzymatic Characterization and Substrate Specificity of Thermostable
from Hyperthermophilic Archaea, Sulfolobus shibatae, Expressed in E. coli
Park, Na-Young ; Cha, Jae-Ho ; Kim, Dae-Ok ; Park, Cheon-Seok ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 454~460
Enzymatic properties and substrate specificity of recombinant
from a hyperthermophilic archaeon, Sulfolobus shibatae (rSSG), were analyzed. rSSG showed its optimum temperature and pH at
and pH 5.0, respectively. Thermal inactivation of rSSG showed that its half-life of enzymatic activity at
was 15 h whereas it drastically decreased to 3.9 min at
. The addition of 10 mM of
enhanced the hydrolysis activity of rSSG up to 23% whereas most metal ions did not show any considerable effect. Dithiothreitol (DTT) and 2-mercaptoethanol exhibited significant influence on the increase of the hydrolysis activity of rSSG rSSG apparently preferred laminaribiose
, followed by sophorose
, and cellobiose
. Various. intermolecular transfer products were formed by rSSG in the lactose reaction, indicating that rSSG prefers lactose as a good acceptor as well as a donor. The strong intermolecular transglycosylation activity of rSSG can be applied in making functional oligosaccharides.
Expression of Enterotoxin Genes in Staphylococcus aureus Isolates Based on mRNA Analysis
Lee, Young-Duck ; Moon, Bo-Youn ; Park, Jong-Hyun ; Chang, Hyo-Ihl ; Kim, Wang-June ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 461~467
Staphylococcus aureus strains are important foodborne pathogens that produce various toxins. To evaluate the risk of the enterotoxins, four S. aureus strains from kimbap and two clinical samples were isolated and identified, and their expression of the enterotoxin genes were analyzed using a reverse transcription real-time PCR. Various enterotoxin genes were detected, including sea, seg, seh, sei, sen, seo, and sem, where each isolate contained one or two. When the mRNA detection of the enterotoxin genes was analyzed using a reverse transcriptase PCR, various levels of expression were found depending on the species and enterotoxin gene. Therefore, it is reasonable to suggest that the poisoning risk of S. aureus can be effectively evaluated based on the gene expression at the mRNA level.
Accurate Delimitation of Phanerochaete chrysosporium and Phanerochaete sordida by Specific PCR Primers and Cultural Approach
Lim, Young-Woon ; Baik, Keun-Sik ; Chun, Jong-Sik ; Lee, Kang-Hyun ; Jung, Won-Jin ; Bae, Kyung-Sook ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 468~473
White rot fungi, Phanerochaete chrysosporium and Phanerochaete sordida, have been mostly studied in a variety of industrial processes like biopulping and pulp bleaching as well as in bioremediation. Whereas P. sordida is widely distributed in the North Temperate Zone, P. chrysosporium is reported in the restricted area and hundreds of reports have been described from a few strains of P. chrysosporium, which are deposited at various fungal collections in the world. The isolates of two species are not easily discriminated because of their morphological and molecular similarity. Through the ITS sequence analyses, a region containing substantial genetic variation between the two species was identified. PCR amplification using two specific primers was successfully used to differentiate P. chrysosporium from P. sordida. These results were supported by cultural studies. The growth rates at
on PDA, MEA, and Cza and the microscopic features of conidia on PDA and YMA were also very useful to differentiate those two species.
Escherichia coli Can Produce Recombinant Chitinase in the Soil to Control the Pathogenesis by Fusarium oxysporum Without Colonization
Chung, Soo-Hee ; Kim, Sang-Dal ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 474~480
Fusarium wilt of cucumbers was effectively controlled by Escherichia coli expressing an endochitinase gene (chiA), and the rate was as effective (60.0%) as the wild-type strain S. proteamaculans 3095 (55.0%) where the gene was cloned. However, live cells of soil inoculated E. coli host harboring the chiA gene did not proliferate but declined 100-fold from
CFU during the first week and showed less than 10 cells after day 14, suggesting that E. coli was able to express and produce the chitinase enzyme to the soil even as the population was gradually decreasing. Because the majority of the strains was alive for only a short period of time and the Fusarium-affected seedlings showed symptoms of wilting within 7-10 days, it seems that the pathogen control was decided early after the introduction of the biocontrol agent, eliminating the survival of the antagonist. These results indicated that soil inoculated E. coli could sufficiently express and produce the recombinant protein to control the pathogen, and root or soil colonization of the antagonist might not be a significant factor in determining the efficacy of biological control.
Rapid Detection and Isolation of Known and Putative
Genes Using Degenerate PCR Primers
Park, Jung-Mi ; Han, Nam-Soo ; Kim, Tae-Jip ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 481~489
]-L-Arabinofuranosidases (AFases; EC 184.108.40.206) are exo-type enzymes, which hydrolyze terminal nonreducing arabinose residues from various polysaccharides such as arabinan and arabinoxylan. Genome-wide BLAST search showed that various bacterial strains possess the putative AFase genes with well-conserved motif sequences at the nucleotide and amino acid sequence levels. In this study, two sets of degenerate PCR primers were designed and tested to detect putative AFase genes, based on their three highly conserved amino acid blocks (PGGNFV, GNEMDG; and DEWNVW). Among 20 Bacillus-associated species, 13 species were revealed to have putative AFase genes in their genome and they share over 67% of amino acid identities with each other. Based on the partial sequence obtained from an isolate, an AFase from Geobacillus sp. was cloned and expressed in E. coli. Enzymatic characterization has verified that the resulting enzyme corresponds to a typical AFase. Accordingly, degenerate PCR primers developed in this work can be used for fast, easy, and specific detection and isolation of putative AFase genes from bacterial cells.
Rapid Identification of Lactobacillus and Bifidobacterium in Probiotic Products Using Multiplex PCR
Sul, Su-Yeon ; Kim, Hyun-Joong ; Kim, Tae-Woon ; Kim, Hae-Yeong ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 490~495
Lactic acid bacteria (LAB) are beneficial for the gastrointestinal tract and reinforce immunity in human health. Recently, many functional products using the lactic acid bacteria have been developed. Among these LAB, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum are frequently used for probiotic products. In order to monitor these LAB in commercial probiotic products, a multiplex PCR method was developed. We designed four species-specific primer pairs for multiplex PCR from the 16S rRNA, 16S-23S rRNA intergenic spacer region, and 23S rRNA genes in Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum. Using these primer pairs, 4 different LAB were detected with high specificity in functional foods. We suggest that the multiplex PCR method developed in this study would be an efficient tool for simple, rapid, and reliable identification of LAB used as probiotic strains.
A Discrete Mathematical Model Applied to Genetic Regulation and Metabolic Networks
Asenjo, J.A. ; Ramirez, P. ; Rapaport, I. ; Aracena, J. ; Goles, E. ; Andrews, B.A. ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 496~510
This paper describes the use of a discrete mathematical model to represent the basic mechanisms of regulation of the bacteria E. coli in batch fermentation. The specific phenomena studied were the changes in metabolism and genetic regulation when the bacteria use three different carbon substrates (glucose, glycerol, and acetate). The model correctly predicts the behavior of E. coli vis-a-vis substrate mixtures. In a mixture of glucose, glycerol, and acetate, it prefers glucose, then glycerol, and finally acetate. The model included 67 nodes; 28 were genes, 20 enzymes, and 19 regulators/biochemical compounds. The model represents both the genetic regulation and metabolic networks in an integrated form, which is how they function biologically. This is one of the first attempts to include both of these networks in one model. Previously, discrete mathematical models were used only to describe genetic regulation networks. The study of the network dynamics generated 8
fixed points, one for each nutrient configuration (substrate mixture) in the medium. The fixed points of the discrete model reflect the phenotypes described. Gene expression and the patterns of the metabolic fluxes generated are described accurately. The activation of the gene regulation network depends basically on the presence of glucose and glycerol. The model predicts the behavior when mixed carbon sources are utilized as well as when there is no carbon source present. Fictitious jokers (Joker1, Joker2, and Repressor SdhC) had to be created to control 12 genes whose regulation mechanism is unknown, since glycerol and glucose do not act directly on the genes. The approach presented in this paper is particularly useful to investigate potential unknown gene regulation mechanisms; such a novel approach can also be used to describe other gene regulation situations such as the comparison between non-recombinant and recombinant yeast strain, producing recombinant proteins, presently under investigation in our group.
Increasing Production in Korean Shrimp Farms with White-Spot Syndrome Virus PCR-Negative Brood Stock
Seok, Seung-Hyeok ; Baek, Min-Won ; Lee, Hui-Young ; Kim, Dong-Jae ; Chun, Myung-Sun ; Kim, Jong-Sheek ; Chang, Se-Ok ; Park, Jae-Hak ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 511~515
White-spot syndrome virus (WSSV) is a devastating, infectious virus affecting shrimp. Although sensitive techniques involving PCR have been developed to assist farmers in screening shrimp (brood stock) for WSSV prior to stocking ponds, such practices have not yet been applied in Korea. Despite the rationality of implementing screening, there has been some doubt as to whether the stocking of WSSV-PCR-negative fly epidemiologically decreases white-spot disease outbreaks. Here, we report a retrospective analysis of data from shrimp farms in the western coast of Korea where WSSV-PCR-negative brood stocks were used to stock rearing ponds. A total of 366 shrimp from Heuksan Island were sampled for WSSV with PCR. Of the tested shrimp, 7.2% (28 brood stocks) were identified as WSSV positive; only WSSV-PCR-negative shrimp were used for brood stocks. Total unit production (final shrimp production/ the area of the ponds) was higher, at 1.96, in ponds where WSSV-PCR-negative shrimp were used, as compared with 1.02 in other ponds in Korea in 2004. This retrospective analysis of WSSV in Korea may be useful to the shrimp aquaculture industry, suggesting a testable hypothesis that may contribute to the eventual control of WSSV outbreaks.
Rapid Detection of Enterobacter sakazakii Using TaqMan Real-Time PCR Assay
Kang, Eun-Sil ; Nam, Yong-Suk ; Hong, Kwang-Won ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 516~519
Enterobacter sakazakii is an emerging food pathogen, which induces severe meningitis and sepsis in neonates and infants, with a high fatality rate. The disease is generally associated with the ingestion of contaminated infant formula. In this study, we describe the development of a real-time PCR protocol to identify E. sakazakii using a TaqMan probe, predicated on the nucleotide sequence data of the 168 rRNA gene obtained from a variety of pathogens. To detect E. sakazakii, four primer sets and one probe were designed. Five strains of E. sakazakii and 28 non-E. sakazakii bacterial strains were used in order to ensure the accuracy of detection. The PCR protocol successfully identified all of the E. sakazakii strains, whereas the 28 non-E. sakazakii strains were not detected by this method. The detection limits of this method for E. sakazakii cells and purified genomic DNA were 2.3 CFU/ assay and 100 fg/assay, respectively. These findings suggest that our newly developed TaqMan real-time PCR method should prove to be a rapid, sensitive, and quantitative method for the detection of E. sakazakii.
Physical Properties of Nisin-Incorporated Gelatin and Corn Zein Films and Antimicrobial Activity Against Listeria monocytogenes
Ku, Kyoung-Ju ; Song, Kyung-Bin ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 520~523
Edible films of gelatin and com zein were prepared by incorporating nisin to the film-forming solutions. Com zein film with nisin of 12,000 IU/ml had an increase of 11.6 MPa in tensile strength compared with the control, whereas gelatin film had a slight increase with the increase of nisin concentration added. Water vapor permeability for both com zein and gelatin films decreased with the increase of nisin concentration, thus providing a better barrier against water. Antimicrobial activity against Listeria monocytogenes increased with the increase of nisin concentration, resulting in 1.4 log cycle reduction for com zein film and 0.6 log cycle reduction for gelatin film at 12,000 IU/ml. These results suggest that incorporation of nisin into com zein and gelatin films improve the physical properties of the films as well as antimicrobial activity against pathogenic bacteria during storage, resulting in extension of the shelf life of food products by providing with antimicrobial edible packaging films.
Physiological Responses of Bacillus amyloliquefaciens Spores to High Pressure
Ahn, Ju-Hee ; Balasubramaniam, V.M. ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 524~529
Pressure inactivation behavior of Bacillus amyloliquefaciens spores was investigated in deionized water. The spores of B. amyloliquefaciens were subjected to
and 700 MPa. The magnitude of the decrease in viability after pressure treatment was similar to that after pressure treatment followed by heat shock. The increase of dipicolinic acid (DPA) release was correlated with the spore inactivation, and the hydrophobicity did not significantly change during the pressure-assisted thermal processing (PATP). Lag phase duration increased with increasing pressure process time. The mechanisms of spore germination and inactivation during the PATP were related to a complex physiological process.
Antimicrobial Effects of Flavone Analogues and Their Structure-Activity Relationships
Young, Jung-Mo ; Park, Young-Hee ; Lee, Yong-Uk ; Kim, Ho-Jung ; Shim, Yhong-Hee ; Ahn, Joong-Hoon ; Lim, Yoong-Ho ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 530~533
It has been well known that the use of Saccharomyces cerevisiae can cause fungemia in critically ill patients and flavone shows an antimicrobial effect on S. cerevisiae. Therefore, we have investigated the activities of thirteen flavone analogues on S. cerevisiae in our studies. Because flavonoids including flavones have antioxidative effects, we try to carry out the activity studies of flavone analogues in vitro and in vivo. In addition, the relationships between the structures of flavone analogues and their biological activities, such as antimicrobial and antioxidative effects, were elucidated using Comparative Molecular Field Analysis calculations. Of the flavone analogues tested here, 3,2'-dihydroxyflavone showed both good antimicrobial and antioxidative activities.
Comparative Transcriptome Analysis for Avermectin Overproduction via Streptomyces avermitilis Microarray System
Im, Jong-Hyuk ; Kim, Myung-Gun ; Kim, Eung-Soo ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 534~538
Avermectin and its analogs are major commercial antiparasitic agents in the fields of animal health, agriculture, and human infections. To increase our understanding about the genetic mechanism underlying avermectin overproduction, comparative transcriptomes were analyzed between the low producer S. avermitilis ATCC31267 and the high producer S. avermitilis ATCC31780 via a S. avermitilis whole genome chip. The comparative transcriptome analysis revealed that fifty S. avermitilis genes were expressed at least two-fold higher in S. avermitilis ATCC31780. In particular, all the avermectin biosynthetic genes, including polyketide synthase (PKS) genes and an avermectin pathway-specific regulatory gene, were less expressed in the low producer S. avermitilis ATCC31267. The present results imply that avermectin overproduction in S. avermitilis ATCC31780 could be attributed to the previously unidentified fifty genes reported here and increased transcription levels of avermectin PKS genes.
Glycosylation of Flavonoids with E. coli Expressing Glycosyltransferase from Xanthomonas campestris
Kim, Jeong-Ho ; Kim, Bong-Gyu ; Kim, Jae-Ah ; Park, Young-Hee ; Lee, Yoon-Jung ; Lim, Yoong-Ho ; Ahn, Joong-Hoon ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 539~542
Glycosyltransferase family 1 (UOT) uses small chemicals including phenolics, antibiotics, and alkaloids as substrates to have an influence in biological activities. A glycosyltransferase (XcGT-2) from Xanthomonas campestris was cloned and consisted of a 1,257 bp open reading frame encoding a 45.5 kDa protein. In order to use this for the modification of phenolic compounds, XcGT-2 was expressed in Escherichia coli as a glutathione S-transferase fusion protein. With the E. coli transformant expressing XcGT-2, biotransformation of flavonoids was carried out. Flavonoids having a double bond between carbons 2 and 3, and hydroxyl groups at both C-3' and C-4', were glycosylated and the glycosylation position was determined to be at the hydroxyl group of C-3', using nuclear magnetic resonance spectroscopy. These results showed that XcGT-2 regiospecifically transferred a glucose molecule to the 3'-hydroxyl group of flavonoids containing both 3' and 4'-hydroxyl groups.
Synthesis and Biological Activity of Fungal Metabolite, 4-Hydroxy-3-(3'-Methyl-2'-Butenyl)-Benzoic Acid
Kim, Hye-Jin ; Kwon, Ho-Jeong ;
Journal of Microbiology and Biotechnology, volume 17, issue 3, 2007, Pages 543~545
4-Hydroxy-3-(3'-methyl-2'-butenyl)-benzoic acid (HMBA) was previously isolated from Curvularia sp. KF119 as a cell-cycle inhibitor. However, the present study used a novel and practical synthetic method to prepare a large quantity of HMBA. The synthetic HMBA was found to inhibit the cell-cycle progression of HeLa cells with a comparable potency to the natural fungal metabolite. The inhibition of the cell-cycle progression by the synthetic HMBA involved both the activation of
and the inhibition of cyclin D1 expression in the cells. Consequently, this new synthetic procedure provides an easy and convenient way to produce or manipulate the original fungal metabolite.