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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Microbiology and Biotechnology
Journal Basic Information
Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
Editor in Chief :
Volume & Issues
Volume 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
Selecting the target year
Isolation and Characterization of Endophytic Actinomycetes from Chinese Cabbage Roots as Antagonists to Plasmodiophora brassicae
Lee, Sun-Og ; Choi, Gyung-Ja ; Choi, Yong-Ho ; Jang, Kyoung-Soo ; Park, Dong-Jin ; Kim, Chang-Jin ; Kim, Jin-Cheol ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1741~1746
DOI : 10.4014/jmb.0800.108
This study was conducted to select endophytic actinomycetes as biocontrol agents against Chinese cabbage clubroot caused by Plasmodiophora brassicae. A total of 81 endophytic actinomycetes were isolated from surface-sterilized roots of Chinese cabbage that was grown on paddy field and upland soils collected from various locations in Korea. By using 16S ribosomal DNA (rDNA) gene sequencing, they were classified to 8 actinobacterial genera. The genus Microbispora (67%) was most frequently isolated, followed by Streptomyces (12%) and Micromonospora (11%). Three of the 81 isolates, when inoculated in germinated Chinese cabbage seeds and then transplanted to pots, effectively suppressed the occurrence of a post-inoculated strain of P. brassicae in the pots. They showed control values of 58% for strain A004, 33% for strain A011, and 42% for strain A018. Based on cell wall components, morphological characteristics, and phylogenetic analyses, the three antagonistic isolates were identified as Microbispora rosea subsp. rosea (A004 and A011) and Streptomyces olivochromogenes (A018). Further researches on the field efficacy and action modes of the three actinomycetes are in progress.
Fixation Gene Expression in Acidithiobacillus ferrooxidans ATCC 23270 by Lix984n Shock
Wang, Wei ; Xiao, Shuiming ; Chao, Jing ; Chen, Qijiong ; Qiu, Guanzhou ; Liu, Xueduan ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1747~1754
DOI : 10.4014/jmb.0700.737
Acidithiobaeillus ferrooxidans ATCC 23270 is an important model organism for bioleaching and bioremediation studies owing to its diverse metabolic capabilities, whereas lix984n is a widely used extractant. Little is known about the response of cbb genes in A. ferrooxidans to lix984n shock. Thus, to elucidate the response of the
fixation genes in A. ferrooxidans ATCC 23270 to the addition of lix984n, the gene expression of cbb genes was examined using a real-time PCR. Although a natural increase or decrease in the expression of most cbb genes was observed after 5 min of shock with 3% (v/v) lix984n, sdhC and cbbR exhibited quick responses to the shock. Ten min of shock had a greater effect on the cbb gene expression, yet 15 min of shock had a significant effect on the Calvin cycle in A. ferrooxidans ATCC 23270, as the expression of all the cbb genes reached a very high level. Therefore, after a short lix984n shock, a solution of A. ferrooxidans can be re-used for bioleaching.
Activation of the Vibrio vulnificus cadBA Operon by Leucine-Responsive Regulatory Protein is Mediated by CadC
Rhee, Jee-Eun ; Kim, Kun-Soo ; Choi, Sang Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1755~1761
DOI : 10.4014/jmb.0800.121
The present study revealed that Lrp, a leucine-responsive regulatory protein, is involved in the regulation of cadBA transcription through activation of
. The influence of Lrp on
was mediated by CadC, and thereby, CadC was able to compensate for the lack of Lrp in the activation of
. Western blot analyses and EMSA demonstrated that the cellular level of CadC was not significantly affected by Lrp, and that Lrp exerted its effect by directly binding to
. These combined results suggested that CadC and Lrp function cooperatively to activate the
rather than sequentially in a regulatory cascade.
Comparison of Pre-Stain Suspension Liquids in the Contrasting Ability of Neutralized Potassium Phosphotungstate for Negative Staining of Bacteria
Kim, Ki-Wooh ; Jung, Woo-Kyung ; Park, Yong-Ho ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1762~1767
DOI : 10.4014/jmb.0800.256
Image contrast of whole bacteria was compared in Staphylococcus aureus and Escherichia coli depending on pre-stain suspension liquids by energy-filtering transmission electron microscopy. The two bacterial strains were suspended in three most commonly used liquids for negative staining (triple distilled water [DW], phosphate-buffered saline [PBS], and nutrient broth [NB]) and directly observed without staining or stained with neutralized potassium phosphotungstate (PTA), respectively. Even though in low contrast, unstained bacteria were observed owing to their inherent electron density and cell shape in zero-loss (elastic scattering) images. After being suspended in PBS, unstained bacteria appeared to have higher contrast and more refined periphery than DW-suspended ones, and extracellular appendage structures such as fimbriae and flagella could be discerned. The unstained bacteria appeared to be invariably surrounded with electron-lucent precipitates, possibly from PBS. As far as delineation of the structures, the combination of DW or PBS suspension with subsequent staining provided the most satisfactory results, as evidenced by the high contrast of bacterial morphology and appendage structures. However, after being suspended in NB and stained with PTA, bacteria often had too high contrast or poor staining, with electron-dense aggregates around the bacteria. These results suggest that suspension with concentrated organic aliquots including broth media before PTA staining could deteriorate image contrast, and should be used only in dilute form for visualizing bacterial morphology and appendage structures. Moreover the contrast enhancement of unstained bacteria by salt granules would be advantageous in demonstrating bacterial sorption of environmental particles like heavy metals, maintaining minimal contrast for cell imaging.
Comparison of In Vivo Nephrotoxicity in the Rabbit by a Pyrrolidinyl-Thio Carbapenem CW-270031
Kim, Jong-Myung ; Ha, Jong-Ryul ; Oh, Se-Woong ; Kim, Hong-Gi ; Lee, Jin-Man ; Kim, Byung-Oh ; Lee, Dong-Gun ; Lee, Sang-Han ; Kim, Jong-Guk ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1768~1772
DOI : 10.4014/jmb.0800.106
CW-270031 is a novel synthesized carbapenem antibiotic with a broad antimicrobial activity. Carbapenem antibiotics are well known for their nephrotoxicity. In this study, we evaluated the nephrotoxicity potential of this compound in rabbits, which are known for being more sensitive than other animals to renal insult. CW-270031 was administered to NZW male rabbits via an ear vein (200 mg/kg, single injection). Blood samples were collected on 2, 3, and 4 days after treatment. Urea nitrogen and creatinine in plasma were quantified. Four days after the treatment, all animals were autopsied and histopathological examinations were performed on their kidneys, revealing that cephaloridine and imipenem were highly nephrotoxic, and cefazolin had mild renal toxicity, whereas CW-270031 as well as meropenem and tienam had no toxicity to the kidney. The present findings suggest that CW-270031 is a potential carbapenem antibiotic with no nephrotoxicity.
Exploring the Effects of Carbon Sources on the Metabolic Capacity for Shikimic Acid Production in Escherichia coli Using In Silico Metabolic Predictions
Ahn, Jung-Oh ; Lee, Hong-Weon ; Saha, Rajib ; Park, Myong-Soo ; Jung, Joon-Ki ; Lee, Dong-Yup ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1773~1784
DOI : 10.4014/jmb.0700.705
Effects of various industrially important carbon sources (glucose, sucrose, xylose, gluconate, and glycerol) on shikimic acid (SA) biosynthesis in Escherichia coli were investigated to gain new insight into the metabolic capability for overproducing SA. At the outset, constraints-based flux analysis using the genome-scale in silico model of E. coli was conducted to quantify the theoretical maximum SA yield. The corresponding flux distributions fueled by different carbon sources under investigation were compared with respect to theoretical yield and energy utilization, thereby identifying the indispensable pathways for achieving optimal SA production on each carbon source. Subsequently, a shikimate-kinase-deficient E. coli mutant was developed by blocking the aromatic amino acid pathway, and the production of SA on various carbon sources was experimentally examined during 51 batch culture. As a result, the highest production rate, 1.92 mmol SA/h, was obtained when glucose was utilized as a carbon source, whereas the efficient SA production from glycerol was obtained with the highest yield, 0.21 mol SA formed per mol carbon atom of carbon source consumed. The current strain can be further improved to satisfy the theoretically achievable SA production that was predicted by in silico analysis.
Inhibition of Diacylglycerol Acyltransferase by Phenylpyropenes Produced by Penicillium griseofulvum F1959
Lee, Seung-Woong ; Rho, Mun-Chual ; Choi, Jung-Ho ; Kim, Koan-Hoi ; Choi, Yong-Seok ; Lee, Hyun-Sun ; Kim, Young-Kook ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1785~1788
DOI : 10.4014/jmb.0800.079
Phenylpyropenes A, B, and C, isolated from Penicillium griseofulvum F1959, inhibited DGAT in rat liver microsomes with
, respectively. In addition, a kinetic analysis using a Lineweaver-Burk plot revealed that phenylpyropene C was a noncompetitive inhibitor of DGAT. The apparent Michaelis constant (
) value and inhibition constant (
) value were calculated to be
, respectively. Moreover, phenylpyropene C inhibited triglyceride formation in HepG2 cells.
Effective Purification of Ginsenosides from Cultured Wild Ginseng Roots, Red Ginseng, and White Ginseng with Macroporous Resins
Li, Huayue ; Lee, Jae-Hwa ; Ha, Jong-Myung ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1789~1791
DOI : 10.4014/jmb.0800.192
This study was aimed (i) to develop an effective method for the purification of ginsenosides for industrial use and (ii) to compare the distribution of ginsenosides in cultured wild ginseng roots (adventitious root culture of Panax ginseng) with those of red ginseng (steamed ginseng) and white ginseng (air-dried ginseng). The crude extracts of cultured wild ginseng roots, red ginseng, and white ginseng were obtained by using a 75% ethanol extraction combined with ultrasonication. This was followed sequentially by AB-8 macroporous adsorption chromatography, Amberlite IRA 900 Cl anion-exchange chromatography, and Amberlite XAD16 adsorption chromatography for further purification. The contents of total ginsenosides were increased from 4.1%, 12.1%, and 11.3% in the crude extracts of cultured wild ginseng roots, red ginseng, and white ginseng to 79.4%, 71.7%, and 72.5% in the final products, respectively. HPLC analysis demonstrated that ginsenosides in cultured wild ginseng roots were distributed in a different ratio compared with red ginseng and white ginseng.
Succinic Acid Production by Anaerobiospirillum succiniciproducens ATCC 29305 Growing on Galactose, Galactose/Glucose, and Galactose/Lactose
Lee, Pyung-Cheon ; Lee, Sang-Yup ; Chan, Ho-Nam ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1792~1796
DOI : 10.4014/jmb.0800.129
Succinic acid-producing Anaerobinspirillum succiniciproducens was anaerobically grown on galactose, galactose/glucose, or galactose/lactose in order to study its galactose fermentation. Unlike a previous report, A. succiniciproducens was found to efficiently metabolize galactose as the sole carbon source at a rate of 2.4 g/g-DCW/h and produced succinic acid with as high a yield of 87% as with using glucose. When glucose and galactose were present, A. succiniciproducens metabolized both sugars simultaneously. Furthermore, when lactose and galactose coexisted, lactose did not inhibit the galactose fermentation of A. succiniciproducens. Therefore, co-utilization of galactose and other sugars can improve the productivity and economy of bio-based succinic acid processes.
Enhanced Production of 1,2-Propanediol by tpil Deletion in Saccharomyces cerevisiae
Jung, Joon-Young ; Choi, Eun-Sil ; Oh, Min-Kyu ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1797~1802
DOI : 10.4014/jmb.0800.010
Saccharomyces cerevisiae was metabolically engineered to improve 1,2-propanediol production. Deletion of the tpil (triosephosphate isomerase) gene in S. cerevisiae increased the carbon flux to DHAP (dihydroxylacetone phosphate) in glycolysis, resulting in increased glycerol production. Then, the mgs and gldA genes, the products of which convert DHAP to l,2-propanediol, were introduced to the tpil-deficient strain using a multicopy plasmid. As expected, the intracellular level of methylglyoxal was increased by introduction of the mgs gene in S. cerevisiae and that of 1,2-propanediol by introduction of both the mgs and gldA genes. As a result, 1.11 g/l of 1,2-propanediol was achieved in flask culture.
Effect of Glutaraldehyde Treatment on Stability of Permeabilized Ochrobactrum anthropi SY509 in Nitrate Removal
Park, Young-Tae ; Park, Jae-Yeon ; Park, Kyung-Moon ; Choi, Suk-Soon ; Yoo, Young-Je ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1803~1808
DOI : 10.4014/jmb.0800.094
For practical application, the stability of permeabilized Ochrobactrum anthropi SY509 needs to be increased, as its half-life of enzymatic denitrification is only 90 days. As the cells become viable after permeabilization treatment, this can cause decreased activity in a long-term operation and induce breakage of the immobilization matrix. However, the organic solvent concentration causing zero cell viability was 50%, which is too high for industrial application. Thus, whole-cell immobilization using glutaraldehyde was performed, and 0.1% (v/v) glutaraldehyde was determined as the optimum concentration to maintain activity and increase the half-life. It was also found that 0.1% (v/v) glutaraldehyde reacted with 41.9% of the total amine residues on the surface of the cells during the treatment. As a result, the half-life of the permeabilized cells was increased from 90 to 210 days by glutaraldehyde treatment after permeabilization, and no cell viability was detected.
Effect of Sulfide Removal on Sulfate Reduction at pH 5 in a Hydrogen Fed Gas-Lift Bioreactor
Bijmans, Martijn F.M. ; Dopson, Mark ; Ennin, Frederick ; Lens, Piet N.L. ; Buisman, Cees J.N. ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1809~1818
DOI : 10.4014/jmb.0800.109
Biotechnological treatment of sulfate- and metal-ions-containing acidic wastewaters from mining and metallurgical activities utilizes sulfate-reducing bacteria to produce sulfide that can subsequently precipitate metal ions. Reducing sulfate at a low pH has several advantages above neutrophilic sulfate reduction. This study describes the effect of sulfide removal on the reactor performance and microbial community in a high-rate sulfidogenic gas-lift bioreactor fed with hydrogen at a controlled internal pH of 5. Under sulfide removal conditions, 99% of the sulfate was converted at a hydraulic retention time of 24 h, reaching a volumetric activity as high as 51 mmol sulfate/l/d. Under nonsulfide removal conditions, <25% of the sulfate was converted at a hydraulic retention time of 24 h reaching volumetric activities of <13 mmol sulfate/l/d. The absence of sulfide removal at a hydraulic retention time of 24 h resulted in an average
concentration of 18.2 mM (584 mg S/I). The incomplete sulfate removal was probably due to sulfide inhibition. Molecular phylogenetic analysis identified 11 separate 16S rRNA bands under sulfide stripping conditions, whereas under nonsulfide removal conditions only 4 separate 16S rRNA bands were found. This shows that a less diverse population was found in the presence of a high sulfide concentration.
Biodegradation and Saccharification of Wood Chips of Pinus strobus and Liriodendron tulipifera by White Rot Fungi
Hwang, Soon-Seok ; Lee, Sung-Jae ; Kim, Hee-Kyu ; Ka, Jong-Ok ; Kim, Kyu-Joong ; Song, Hong-Gyu ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1819~1825
DOI : 10.4014/jmb.0800.231
Degradation and glucose production from wood chips of white pine (Pinus strobus) and tulip tree (Liriodendron tulipifera) by several white rot fungi were investigated. The highest weight losses from 4 g of wood chips of P. strobus and L. tulipifera by the fungal degradation on yeast extract-malt extract-glucose agar medium were 38% of Irpex lacteus and 93.7% of Trametes versicolor MrP 1 after 90 days, respectively. When 4 g of wood chips of P. strobus and L. tulipifera biodegraded for 30 days were treated with cellulase, glucose was recovered at the highest values of 106 mg/g degraded wood by I. lacteus and 450 mg/g degraded wood by T. versicolor. The weight loss of 10 g of wood chip of L. tulipifera by T. versicolor on the nutrient non-added agar under the nonsterile conditions was 35% during 7 weeks of incubation, and the cumulative amount of glucose produced during this period was 239 mg without cellulase treatment. The activities of ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) of fungi tested did not show a high correlation with degradation of the wood chips and subsequent glucose formation. These results suggest that the selection of proper wood species and fungal strain and optimization of glucose recovery are all necessary for the fungal pretreatment of woody biomass as a carbon substrate.
Bacterial Community and Biological Nitrate Removal: Comparisons of Autotrophic and Heterotrophic Reactors for Denitrification with Raw Sewage
Lee, Han-Woong ; Park, Yong-Keun ; Choi, Eui-So ; Lee, Jin-Woo ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1826~1835
DOI : 10.4014/jmb.0800.276
An autotrophic denitrification reactor (ADR-l) and a heterotrophic denitrification reactor (HDR-2) were operated to remove nitrate and nitrite in an anoxic environment in raw sewage. The
-N removal rate of ADR-l was shown to range from 52.8% to 78.7%, which was higher than the
-N removal rate of HDR-2. Specific denitrification rates (SDNR) of ADR-l and HDR-2 were 3.0 to 4.0 and 1.1 to
-N/gVSS/h, respectively. From results of restriction fragment length polymorphism (RFLP) of the 16S rRNA gene, Aquaspirillum metamorphum, Alcaligenes defragrans, and Azoarcus sp. were
-Proteobacteria that are affiliated with denitritying bacteria in the ADR-l. Specifically, Thiobacillus denitrificans was detected as an autotrophic denitrification bacteria. In HDR-2, the
-Proteobacteria such as Denitritying-Fe-oxidizing bacteria, Alcaligenes defragrans, Acidovorax sp., Azoarcus denitrificans, and Aquaspirillum metamorphum were the main bacteria related to denitrifying bacteria. The
-Proteobacteria were the important bacterial groups in ADR-l, whereas the
-Proteobacteria were the main bacterial group in HDR-2 based on results of fluorescent in situ hybridization (FISH). The number of Thiobacillus denitrificans increased in ADR-l during the operation period but not in HRD-2. Overall, the data presented here demonstrate that many heterotrophic denitritying bacteria coexisted with autotrophic denitrifying bacteria such as Thiobacillus denitrificans for nitrate removal in ADR-l. On the other hand, only heterotrophic denitritying bacteria were identified as dominant bacterial groups in HDR-2. Our research may provide a foundation for the complete nitrate removal in raw sewage of low-COD concentration under anoxic condition without any external organic carbon or the requirement of post-treatment.
Stability and Antibacterial Activity of Bacteriocins Produced by Bacillus thuringiensis and Bacillus thuringiensis ssp. kurstaki
Jung, Woo-Jin ; Mabood, Fazli ; Souleimanov, Alfred ; Zhou, Xiaomin ; Jaoua, Samir ; Kamoun, Fakher ; Smith, Donald L. ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1836~1840
DOI : 10.4014/jmb.0800.120
Bacteriocins are antimicrobial peptides that are produced by bacteria and toxic to bacterial strains closely related to the producer strain. It has previously been reported that Bacillus thuringiensis strain NEB17 and Bacillus thuringiensis subsp. kurstaki BUPM4 produce the bacteriocins thuricin 17 (3,162 Da) and bacthuricin F4 (3,160.05 Da), respectively. Here, we demonstrate that these bacteriocins have functional similarities and show a similar spectrum of antimicrobial activities against indicator strains. We also studied the effects of sterilization methods on the recovery and biological activities of these bacteriocins. They were completely degraded by autoclaving and the two were similarly affected by the tested filter membranes. Polyvinylidene fluoride (PVDF), polyestersulfone (PES), and cellulose acetate (CA) are suitable for filter sterilization of these bacteriocins. The two bacteriocins were stable across a range of storage conditions. These data will facilitate their utilization in food preservation or agricultural applications.
Application of the rpoS Gene for Species-Specific Detection of Vibrio vulnificus by Real-Time PCR
Kim, Dong-Gyun ; Ahn, Sun-Hee ; Kim, Lyoung-Hwa ; Park, Kee-Jai ; Hong, Yong-Ki ; Kong, In-Soo ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1841~1847
DOI : 10.4014/jmb.0800.176
Vibrio vulnificus is a causative agent of serious diseases in humans, resulting from the contact of wound with seawater or consumption of raw seafood. Several studies aimed at detecting V. vulnificus have targeted vvh as a representative virulence toxin gene belonging to the bacterium. In this study, we targeted the rpoS gene, a general stress regulator, to detect V. vulnificus. PCR specificity was identified by amplification of 8 V. vulnificus templates and by the loss of a PCR product with 36 non-V. vulnificus strains. The PCR assay had the 273-bp fragment and the sensitivity of 10 pg DNA from V. vulnificus. SYBR Green I-based real-time PCR assay targeting the rpoS gene showed a melting temperature of approximately
for the V. vulnificus strains. The minimum level of detection by real-time PCR was 2 pg of purified genomic DNA, or
V. vulnificus cells from pure cultured broth and
cells in 1 g of oyster tissue homogenates. These data indicate that real-time PCR is a sensitive, species-specific, and rapid method for detecting this bacterium, using the rpoS gene in pure cultures and in infected oyster tissues.
In Vitro Activity of Methyl Gallate Isolated from Galla Rhois Alone and in Combination with Ciprofloxacin Against Clinical Isolates of Salmonella
Choi, Jang-Gi ; Kang, Ok-Hwa ; Lee, Young-Seob ; Oh, You-Chang ; Chae, Hee-Sung ; Jang, Hye-Jin ; Kim, Jong-Hak ; Sohn, Dong-Hwan ; Shin, Dong-Won ; Park, Hyun ; Kwon, Dong-Yeul ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1848~1852
DOI : 10.4014/jmb.0800.025
Salmonella remains a primary cause of food poisoning worldwide, and massive outbreaks have been witnessed in recent years. Therefore, this study investigated the antimicrobial activity of methyl gallate (MG), which exhibited good antibacterial activity (
) against all the bacterial strains tested. In a checkerboard dilution test, MG markedly lowered the MICs of ciprofloxacin (CPFX) against Salmonella. The combined activity of CPFX and MG against Salmonella resulted in fractional inhibitory concentrations (FICs) ranging from 0.0037 to 0.015 and from 0.24 to
, respectively. Meanwhile, the FIC index ranged from 0.31-0.37, indicating a marked synergistic relationship between CPFX and MG against Salmonella. Time-kill assays also showed a decrease in the CFU/ml between the combination and the more active compound. Therefore, this study demonstrated that MG and CPFX can act synergistically in inhibiting Salmonella in vitro.
Contamination of Chicken Meat with Salmonella enterica Serovar Haardt with Nalidixic Acid Resistance and Reduced Fluoroquinolone Susceptibility
Lee, Ki-Eun ; Lee, Min-Young ; Lim, Ji-Youn ; Jung, Ji-Hun ; Park, Yong-Ho ; Lee, Yeon-Hee ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1853~1857
DOI : 10.4014/jmb.0800.221
Salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. A total of 21 isolates of Salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. Among these, 18 isolates were identified as Salmonella enterica serotype Haardt (S. Haardt) and three isolates were S. enterica serotype Muenchen. When the minimal inhibitory concentrations of the S. Haardt isolates were assayed with the agar dilution method to determine susceptibility to ampicillin, chloramphenicol, sulfisoxazole, tetracycline, and nalidixic acid, all 18 isolates were resistant to tetracycline and nalidixic acid and nine of these were resistant to ampicillin. These isolates showed reduced susceptibility to eight fluoroquinolones including ciprofloxacin, enrofloxacin, levofloxacin, gatifloxacin, gemifloxacin, moxifloxacin, norfloxacin, and ofloxacin. When quinolone resistance determining regions of gyrA and gyrB were sequenced, every isolate had the same missense mutation Ser83
+TAC) in gyrA, whereas no mutation was found in gyrB. Pulsed-field gel electrophoresis with XbaI revealed a close relationship among these isolates, suggesting a contamination of raw chicken meat with clonal spread of nalidixic acid-resistant and quinolone-reduced susceptibility S. Haardt in chickens. Results in this study show the importance of a well-equipped cold system and the prudent use of fluoroquinolone in chickens to prevent the occurrence of quinolone-resistant isolates.
Rapid and Sensitive Detection of Listeria monocytogenes Using a PCR-Enzyme-Linked Immunosorbent Assay
Kim, Hye-Jin ; Cho, Jae-Chang ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1858~1861
DOI : 10.4014/jmb.0800.409
A PCR-enzyme-linked immunosorbent assay (PCR-ELISA) was developed for the rapid and sensitive detection of L. monocytogenes. PCR primers generating a 132-bp amplicon and a capture probe able to hybridize to the PCR amplicon were designed based on the L. monocytogenes-specific hly gene encoding listeriolysin. The detection limit of PCR-ELISA for L. monocytogenes was determined to be as low as 10 cells per PCR reaction, and this level of detection was achieved within 5 h. These results indicate that the PCR-ELISA provides a valuable tool for the rapid and sensitive detection of L. monocytogenes for the ready-to-eat food industry.
Streptochlorin Isolated from Streptomyces sp. Induces Apoptosis in Human Hepatocarcinoma Cells Through a Reactive Oxygen Species-Mediated Mitochondrial Pathway
Shin, Dong-Yeok ; Shin, Hee-Jae ; Kim, Gi-Young ; Cheong, Jae-Hun ; Choi, Il-Whan ; Kim, Se-Kwon ; Moon, Sung-Kwon ; Kang, Ho-Sung ; Choi, Yung-Hyun ;
Journal of Microbiology and Biotechnology, volume 18, issue 11, 2008, Pages 1862~1867
DOI : 10.4014/jmb.0800.124
Streptochlorin is a small molecule isolated from marine Streptomyces sp. that is known to have antiangiogenic and anticancer properties. In this study, we examined the effects of this compound on reactive oxygen species (ROS) production and the association of these effects with apoptotic tumor cell death, using a human hepatocarcinoma Hep3B cell line. The results of this study demonstrated that streptochlorin mediates ROS production, and that this mediation is followed by a decrease in the mitochondrial membrane potential (MMP,
), activation of caspase-3, and downregulation of antiapoptotic Bcl-2 protein. The quenching of ROS generation by N-acetyl-L-cysteine administration, a scavenger of ROS, reversed the streptochlorin-induced apoptosis effects via inhibition of ROS production, MMP collapse, and the subsequent activation of caspase-3. These observations clearly indicate that ROS are involved in the early molecular events in the streptochlorin-induced apoptotic pathway. Taken together, our data imply that streptochlorin-induced ROS is a key mediator of MMP collapse, which leads to the caspase-3 activation, culminating in apoptosis.