Go to the main menu
Skip to content
Go to bottom
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 20, Issue 12 - Dec 2010
Volume 20, Issue 11 - Nov 2010
Volume 20, Issue 10 - Oct 2010
Volume 20, Issue 9 - Sep 2010
Volume 20, Issue 8 - Aug 2010
Volume 20, Issue 7 - Jul 2010
Volume 20, Issue 6 - Jun 2010
Volume 20, Issue 5 - May 2010
Volume 20, Issue 4 - Apr 2010
Volume 20, Issue 3 - Mar 2010
Volume 20, Issue 2 - Feb 2010
Volume 20, Issue 1 - Jan 2010
Selecting the target year
The Scenario of Norovirus Contamination in Food and Food Handlers
Zainazor, Tuan ; Hidayah, M.S. Noor ; Chai, L.C. ; Tunung, R. ; Ghazali, F. Mohamad ; Son, R. ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 229~237
DOI : 10.4014/jmb.0906.06032
Recently, many cases related to viral gastroenteritis outbreaks have been reported all over the world. Noroviruses are found to be leading as the major cause of outbreaks of acute gastroenteritis. Patients with acute gastroenteritis are normally found to be positive with norovirus when the stools and vomit are analyzed. This paper reviews various activities and previous reports that describe norovirus contamination in various food matrixes and the relationship between food handlers. Lately, a numbers of norovirus outbreaks have been reported that are involved with fresh produce (such as vegetables, fruits), shellfish, and prepared food. Food produce processed by infected food handlers may therefore become easily contaminated. In addition, foods that required much handling and had been eaten without heat treatment gave the high risk for getting foodborne illnesses. The standard method for detection of norovirus has already been available for stool samples. However, only a few methods for detection of norovirus in food samples have been developed until now.
Movement of Rhizobia Inside Tobacco and Lifestyle Alternation from Endophytes to Free-Living Rhizobia on Leaves
Ji, Kui-Xian ; Chi, Feng ; Yang, Ming-Feng ; Shen, Shi-Hua ; Jing, Yu-Xiang ; Dazzo, Frank B. ; Cheng, Hai-Ping ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 238~244
DOI : 10.4014/jmb.0906.06042
Rhizobia are well-known for their ability to infect and nodulate legume roots, forming a nitrogen-fixing symbiosis of agricultural importance. In addition, recent studies have shown that rhizobia can colonize roots and aerial plant tissues of rice as a model plant of the Graminaceae family. Here we show that rhizobia can invade tobacco, a model plant belonging to the Solanaceae family. Inoculation of seedling. roots with five GFP-tagged rhizobial species followed by microscopy and viable plating analyses indicated their colonization of the surface and interior of the whole vegetative plant. Blockage of ascending epiphytic migration by coating the hypocotyls with Vaseline showed that the endophytic rhizobia can exit the leaf interior through stomata and colonize the external phyllosphere habitat. These studies indicate rhizobia can colonize both below- and above-ground tissues of tobacco using a dynamic invasion process that involves both epiphytic and endophytic lifestyles.
Quantitative Analysis of Human- and Cow-Specific 16S rRNA Gene Markers for Assessment of Fecal Pollution in River Waters by Real-Time PCR
Jeong, Ju-Yong ; Park, Hee-Deung ; Lee, Kyong-Hee ; Hwang, Jae-Hong ; Ka, Jong-Ok ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 245~253
DOI : 10.4014/jmb.0908.08022
The base sequences representing human- and cow-specific 168 rRNA gene markers identified in a T-RFLP analysis were recovered from clone libraries. The human- and cow-specific primers were designed from these sequences and their specificities were analyzed with fecal DNAs from human, cow, and pig. The AllBac primer set showed positive results for all human, cow, and pig samples, whereas the human-specific primer set showed positive result only for the human sample but not for the cow or pig samples. Likewise, the cow-specific primer set showed positive results only for the cow sample but not for the human or pig samples. Real-time PCR assay with these primers was developed for the identification and quantification of fecal pollution in the river water. The human- and cow-specific markers were detected in the order of 9
copies per gram wet feces, which were two orders of magnitude lower than those of total Bacteroidales. For the river water samples, the human-specific marker was detected in
copies/100 ml water, which was 2.4-4.9 orders of magnitude lower than those of total Bacteroidales. There was no significant correlation between total Bacteroidales and conventional fecal indicators, but there was a high correlation between Bacteroidales and the human-specific marker. This assay could reliably identify and quantify the fecal pollution sources, enabling effective measures in the watersheds and facilitating water quality management.
Functional Characteristics and Diversity of a Novel Lignocelluloses Degrading Composite Microbial System with High Xylanase Activity
Guo, Peng ; Zhu, Wanbin ; Wang, Hui ; Lu, Yucai ; Wang, Xiaofen ; Zheng, Dan ; Cui, Zongjun ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 254~264
DOI : 10.4014/jmb.0906.06035
To obtain an efficient natural lignocellulolytic complex enzyme, we screened an efficient lignocellulose-degrading composite microbial system (XDC-2) from composted agricultural and animal wastes amended soil following a long-term directed acclimation. Not only could the XDC-2 degrade natural lignocelluloses, but it could also secrete extracellular xylanase efficiently in liquid culture under static conditions at room temperature. The XDC-2 degraded rice straw by 60.3% after fermentation for 15 days. Hemicelluloses were decomposed effectively, whereas the extracellular xylanase activity was dominant with an activity of 8.357 U/ml on day 6 of the fermentation period. The extracellular crude enzyme noticeably hydrolyzed natural lignocelluloses. The optimum temperature and pH for the xylanase activity were
and 6.0. However, the xylanase was activated in a wide pH range of 3.0-10.0, and retained more than 80% of its activity at
and pH 5.0-8.0 after three days of incubation in liquid culture under static conditions. PCR-DGGE analysis of successive subcultures indicated that the XDC-2 was structurally stable over long-term restricted and directed cultivation. Analysis of the 168 rRNA gene clone library showed that the XDC-2 was mainly composed of mesophilic bacteria related to the genera Clostridium, Bacteroides, Alcaligenes, Pseudomonas, etc. Our results offer a new approach to exploring efficient lignocellulolytic enzymes by constructing a high-performance composite microbial system with synergistic complex enzymes.
Molecular Cloning and Characterization of Two Major Endoglucanases from Penicillium decumbens
Wei, Xiao-Min ; Qin, Yu-Qi ; Qu, Yin-Bo ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 265~270
DOI : 10.4014/jmb.0904.04047
Two major endoglucanase genes (cel7B and cel5A) were cloned from Penicillium decumbens 114-2 using the method of modified thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR). The result of Southern blotting suggested that P. decumbens has a single copy of the cel5A gene and a single copy of the cel7B gene in its chromosomal DNA. The expression levels of cel5A and cel7B were determined by means of real-time quantitative PCR, suggesting that the two genes were coordinately expressed, and repressed by glucose and induced by cellulose. Both endoglucanase genes were expressed in Saccharomyces cerevisiae and the recombinant proteins were purified. The recombinant Cel7B and Cel5A were both optimally active at
and pH 4.0. The recombinant Cel7B showed more than 8-fold, 30-fold, and 5-fold higher enzyme activities toward carboxymethyl cellulose, barley
-glucan, and PASC, respectively, in comparison with that of Cel5A. However, their activities toward pNPC and Avicel showed minor differences. The results suggested that Cel7B is a strict endoglucanase, whereas Cel5A showed processivity because of its relative higher ability to hydrolyze the crystal cellulose.
Vibrio alginolyticus MviN is a LuxO-regulated Protein and Affects Cytotoxicity Towards Epithelioma Papulosum Cyprini (EPC) Cells
Cao, Xiaodan ; Wang, Qiyao ; Liu, Qin ; Liu, Huan ; He, Honghong ; Zhang, Yuanxing ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 271~280
DOI : 10.4014/jmb.0904.04031
Vibrio alginolyticus, a Gram-negative marine bacterium, is one of the causative agents of fish vibriosis. Its virulence factors and pathogenesis mechanism are barely known, except for some extracellular products (ECPs) that are known to be regulated by quorum sensing system. Therefore, the present study used a microarray to analyze the transcription profiles of the wild-type V. alginolyticus and a deletion mutant of luxO, the pivotal regulator in Vibrio quorum sensing systems, which resulted in the identification of a putative virulence factor, MviN. Quantitative real-time reverse transcription PCR confirmed that the transcription of mviN was upregulated in the luxO mutant when compared with wild-type, and down regulated in a luxO-con complemented strain. Furthermore, Western blotting indicated that MviN was greatly induced during the late-exponential and stationary phases of growth, indicating that the expression of MviN was cell-density dependent and quorum sensing regulated in V. alginolyticus. Meanwhile, the mviN null mutant displayed a much slower growth rate than the wild type, signifying the essential role of MviN in V. alginolyticus. Western blotting also revealed that MviN was present as an extracellular protein in V. alginolyticus. When epithelioma papulosum cyprini (EPC) cells were treated with the ECPs of the mviN mutant, no cytotoxicity was observed, whereas EPC cells treated with the wild type exhibited pathological changes, which increased with the ECPs concentration and treatment time. Therefore, the results demonstrated that MviN is a LuxO-regulated ECPs component and involved in the pathogenicity of V. alginolyticus.
A Genetically Engineered Pseudomonas fluorescens Strain Possesses Dual Activity Against Phytopathogenic Fungi and Insects
Lu, Wenwei ; Zhang, Weiqiong ; Bai, Yan ; Fu, Yingying ; Chen, Jun ; Geng, Xiaolu ; Wang, Yujing ; Xiao, Ming ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 281~286
DOI : 10.4014/jmb.0908.08005
A Pseudomonas fluorescens strain was isolated and found to show antagonistic activity against phytopathogenic fungi and to possess a gene responsible for production of antibiotic 2,4-diacetylphloroglucinol. For the extension of biocontrol range, a gene for an Androetonus australis Hector insect toxin 1 (AaHIT1), one of the most known toxic insect-selective peptides, was designed and synthesized according to the preferred codon usage of Pseudomonas fluorescens, cloned, and transformed into the strain by pSUP106 vector, a broad-host-range plasmid. Bioassays indicated that the engineered strain was able to produce AaHIT1 with insecticidal activity, and at the same time retain the activity against plant pathogen. The experiments for nonplanted soil and rhizosphere colonization showed that, similar to the population of the wild-type strain, that of the engineered strain remained relatively constant in the first 10 days, and the subsequent 50 days, suggesting that AaHIT1 expression in the bacterial cell does not substantially impair its long-term colonization. It is first reported that a Pseudomonas fluorescens strain expressing an active scorpion neurotoxin has dual activity against phytopathogenic fungi and insects, making at attractive for agronomic applications.
Highly Sensitive PNA Array Platform Technology for Single Nucleotide Mismatch Discrimination
Choi, Jae-Jin ; Jang, Min-Jeong ; Kim, Ji-Hyun ; Park, Hee-Kyung ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 287~293
DOI : 10.4014/jmb.0903.04018
Reliable discrimination of a single nucleotide mismatch was demonstrated using arrays with peptide nucleic acid (PNA) probes. The newly developed PNA probes immobilization method and hybridization conditions for PNA arrays gave excellent specificity and sensitivity. In addition we compared the specificity, sensitivity, and stability obtained with the PNA and DNA arrays in discriminating single nucleotide mismatches. The PNA arrays had superior perfect match-to-mismatch signal ratios and sensitivities. The relative signal intensities of mismatch PNA probes ranged from 1.6% to 12.1% of the perfect-match PNA probes. These results demonstrated that the PNA arrays were 2.0 to 37.3 times more specific and about 10 times more sensitive than DNA arrays. The PNA array showed the same specificity and sensitivity after 12-month storage at room temperature.
Functional Roles of the Aromatic Residues in the Stabilization of the [
] Cluster in the Iro Protein from Acidithiobacillus ferrooxidans
Zeng, Jia ; Liu, Qing ; Zhang, Xiaojian ; Mo, Hongyu ; Wang, Yiping ; Chen, Qian ; Liu, Yuandong ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 294~300
DOI : 10.4014/jmb.0906.06040
The Iro protein is a member of the HiPIP family with the [
] cluster for electron transfer. Many reports proposed that the conserved aromatic residues might be responsible for the stability of the iron-sulfur cluster in HiPIP. In this study, Tyr10 was found to be a critical residue for the stability of the [
] cluster, according to site-directed mutagenesis results. Tyr10, Phe26, and Phe48 were essential for the stability of the [
] cluster under acidic condition. Trp44 was not involved in the stability of the [
] cluster. Molecular structure modeling for the mutant Tyr10 proteins revealed that the aromatic group of Tyr10 may form a hydrophobic barrier to protect the [
] cluster from solvent.
Three Non-Aspartate Amino Acid Mutations in the ComA Response Regulator Receiver Motif Severely Decrease Surfactin Production, Competence Development, and Spore Formation in Bacillus subtilis
Wang, Xiaoyu ; Luo, Chuping ; Liu, Youzhou ; Nie, Yafeng ; Liu, Yongfeng ; Zhang, Rongsheng ; Chen, Zhiyi ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 301~310
DOI : 10.4014/jmb.0906.06025
Bacillus subtilis strains produce a broad spectrum of bioactive peptides. The lipopeptide surfactin belongs to one well-known class, which includes amphiphilic membrane-active biosurfactants and peptide antibiotics. Both the srfA promoter and the ComP-ComA signal transduction system are an important part of the factor that results in the production of surfactin. Bs-M49, obtained by means of low-energy ion implantation in wild-type Bs-916, produced significantly lower levels of surfactin, and had no obvious effects against R. solani. Occasionally, we found strain Bs-M49 decreased spore formation and the development of competence. Blast comparison of the sequences from Bs-916 and M49 indicate that there is no difference in the srfA operon promoter PsrfA, but there are differences in the coding sequence of the comA gene. These differences result in three missense mutations within the M49 ComA protein. RT-PCR analyses results showed that the expression levels of selected genes involved in competence and sporulation in both the wild-type Bs-916 and mutant M49 strains were significantly different. When we integrated the comA ORF into the chromosome of M49 at the amyE locus, M49 restored hemolytic activity and antifungal activity. Then, HPLC analyses results also showed the comA-complemented strain had a similar ability to produce surf actin with wild-type strain Bs-916. These data suggested that the mutation of three key amino acids in ComA greatly affected the biological activity of Bacillus subtilis. ComA protein 3D structure prediction and motif search prediction indicated that ComA has two obvious motifs common to response regulator proteins, which are the N-terminal response regulator receiver motif and the C-terminal helix-turn-helix motif. The three residues in the ComA N-terminal portion may be involved in phosphorylation activation mechanism. These structural prediction results implicate that three mutated residues in the ComA protein may play an important role in the formation of a salt-bridge to the phosphoryl group keeping active conformation to subsequent regulation of the expression of downstream genes.
In Vitro Screening for Antimicrobial Activity of Chitosans and Chitooligosaccharides, Aiming at Potential Uses in Functional Textiles
Fernandes, Joao C. ; Tavaria, Freni K. ; Fonseca, Susana C. ; Ramos, Oscar S. ; Pintado, Manuela E. ; Malcata, F. Xavier ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 311~318
DOI : 10.4014/jmb.0904.04038
Antimicrobial finishing of textiles has been found to be an economical way to prevent (or treat) skin disorders. Hence, this research effort was aimed at elucidating the relationship between the molecular weight (MW) of chitosan and its antimicrobial activity upon six dermal reference microorganisms, as well as the influence of the interactions with cotton fabrics on said activity. Using 3 chitosans with different MWs, as well as two chitooligosaccharide (COS) mixtures, a relevant antimicrobial effect was observed by 24 h for the six microorganisms tested; it was apparent that the antimicrobial effect is strongly dependent on the type of target microorganism and on the MW of chitosan - being higher for lower MW in the case of E. coli, K. pneumoniae, and P. aeruginosa, and the reverse in the case of both Gram-positive bacteria. Furthermore, a strong antifungal effect was detectable upon C. albicans, resembling the action over Gram-positive bacteria. Interactions with cotton fabric resulted in a loss of COS activity when compared with cultured media, relative to the effect over Gram-negative bacteria. However, no significant differences for the efficacy of all the 5 compounds were observed by 4 h. The three chitosans possessed a higher antimicrobial activity when impregnated onto the fabric, and presented a similar effect on both Gram-positive bacteria and yeast, in either matrix. Pseudomonas aeruginosa showed to be the most resistant microorganism to all five compounds.
Antifungal Activities of Ethanolic Extract from Jatropha curcas Seed Cake
Saetae, Donlaporn ; Suntornsuk, Worapot ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 319~324
DOI : 10.4014/jmb.0905.05035
Phorbol ester extraction was carried out from Jatropha curcas seed cake, a by-product from the biodiesel fuel industry. Four repeated extractions from 5 g of J. curcas seed cake using 15 ml of 90% (v/v) ethanol and a shaking speed of 150 rpm gave the highest yield of phorbol esters. The ethanolic extract of J. curcas seed cake showed antifungal activities against important fungal phytopathogens: Fusarium oxysporum, Pythium aphanidermatum, Lasiodiplodia theobromae, Curvularia lunata, Fusarium semitectum, Colletotrichum capsid, and Colletotrichum gloeosporioides. The extract contained phorbol esters mainly responsible for antifungal activities. The extract could therefore be used as an antifungal agent for agricultural applications.
Biotransformation of Amides to Acids Using a Co-Cross-Linked Enzyme Aggregate of Rhodococcus erythropolis Amidase
Park, Hyun-Joo ; Uhm, Ki-Nam ; Kim, Hyung-Kwoun ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 325~331
DOI : 10.4014/jmb.0909.09009
Rhodococcus erythropolis amidase was expressed in Escherichia coli cells. The crude amidase in the cell-free extract was immobilized using the cross-linked enzyme aggregate (CLEA) method. The crude amidase was mixed with bovine serum albumin and then precipitated with ammonium sulfate. The resultant precipitant was subsequently cross-linked with glutaraldehyde. Scanning electron microscopy revealed that this co-CLEA had a ball-like shape with a diameter of approximately
. This co-CLEA evidenced hydrolytic activity toward a variety of amide substrates. The amidase co-CLEA evidenced an optimum temperature of
and an optimum pH of 8.0, results that were similar to those of the soluble amidase. The reaction stability of the co-CLEA was increased. That is, it was stable up to
and in a pH range of 5.0-12.0. Additionally, the co-CLEA could be recovered by centrifugation, and retained 96% activity after 3 repeated cycles. This amidase co-CLEA may prove useful as a substitute for soluble amidase as a biocatalyst in the pharmaceutical and chemical industries.
Immobilization and Stability of Lipase from Mucor racemosus NRRL 3631
Adham, Nehad Zaki ; Ahmed, Hanan Mostafa ; Naim, Nadia ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 332~339
DOI : 10.4014/jmb.0906.06059
The lipase from Mucor racemosus NRRL 3631 was partially purified by fractional precipitation using 60% ammonium sulfate, which resulted in a 8.33-fold purification. The partially purified lipase was then immobilized using different immobilization techniques: physical adsorption, ionic binding, and entrapment. Entrapment in a 4% agar proved to be the most suitable technique (82% yield), as the immobilized lipase was more stable at acidic and alkaline pHs than the free enzyme, plus 100% of the original activity was retained owing to the thermal stability of the immobilized enzyme after heat treatment for 60 min at
. The calculated half-lives (472.5, 433.12, and 268.5 min at 50, 55, and
, respectively) and the activation energy (9.85 kcal/mol) for the immobilized enzyme were higher than those for the free enzyme. Under the selected conditions, the immobilized enzyme had a higher
(11.11 mM) and lower
(105.26 U/mg protein) when compared with the free enzyme (8.33 mM and 125.0 U/mg protein, respectively). The operational stability of the biocatalyst was tested for both the hydrolysis of triglycerides and esterification of fatty acids with glycerol. After 4 cycles, the immobilized lipase retained approximately 50% and 80% of its original activity in the hydrolysis and esterification reactions, respectively.
Production of 1,3-Dihydroxyacetone from Glycerol by Gluconobacter oxydans ZJB09112
Hu, Zhong-Ce ; Liu, Zhi-Qiang ; Zheng, Yu-Guo ; Shen, Yin-Chu ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 340~345
DOI : 10.4014/jmb.0907.07011
The culture variables were optimized to increase 1,3-dihydroxyacetone (DHA) production by Gluconohacter oxydans ZJB09112 in shake flasks and bubble column bioreactors. After fermentation in the optimized medium (g/l: yeast extract 5, glycerol 2.5, mannitol 22.5,
2.0, pH 5.0), when five times of glycerol feeding were applied,
of DHA was attained at a
conversion rate of glycerol to DHA.
Effect of Limited Oxygen Supply on Coenzyme
Production and Its Relation to Limited Electron Transfer and Oxidative Stress in Rhizobium radiobacter T6102
Seo, Myung-Ji ; Kim, Soon-Ok ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 346~349
DOI : 10.4014/jmb.0909.09021
) production from Rhizobium radiobacter T6102 was monitored under various oxygen supply conditions by controlling the agitation speeds, aeration rates, and dissolved oxygen levels. As the results, the
production was enhanced by limited oxygen supply. To investigate whether the
production is associated with its physiological functions of electron carrier and antioxidant, the effects of sodium azide and hydrogen peroxide on the
production were studied, showing that the
contents were slightly enhanced with increasing sodium azide (up to 0.4 mM) and hydrogen peroxide (up to
) concentrations. These results suggest the plausible mechanism where the limited electron transfer stimulating the environments of limited oxygen supply and oxidative stress could accumulate the
, providing the relationship between the
physiological functions and its regulation system.
Simple Purification of the Human Antimicrobial Peptide Dermcidin (MDCD-1L) by Intein-Mediated Expression in E. coli
Hong, In-Pyo ; Kim, Yong-Seok ; Choi, Shin-Geon ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 350~355
DOI : 10.4014/jmb.0907.07029
Among human antimicrobial peptides (hAMPs), DCD-1L has a broad spectrum of antimicrobial activity over a wide pH range and in high salt concentrations. It offers a promising alternative to conventional antibiotics. The 458-bp-long dermcidin cDNA was amplified by PCR using a human fetal cDNA library as a template. The 147-bp fragment of the MDCD-1L gene encoding an additional methionine residue was subcloned into the pTYB11 vector. Recombinant MDCD-1L was expressed as an intein fusion protein in E. coli, and then purified by affinity chromatography using chitin beads. A small peptide with a molecular mass of about 5 kDa was detected by tricine gel electrophoresis. The recombinant MDCD-1L peptide was purified from the gel and its amino acid sequence was determined by nanoLC-ESI-MS/MS analysis. The initiating amino acid, methionine, remained attached to the N-terminal region of recombinant MDCD-1L. Purified MDCD-1L showed antimicrobial activity against a Micrococcus luteus test strain.
Effect of Expression of Genes in the Sphingolipid Synthesis Pathway on the Biosynthesis of Ceramide in Saccharomyces cerevisiae
Kim, Se-Kyung ; Noh, Yong-Ho ; Koo, Ja-Ryong ; Yun, Hyun-Shik ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 356~362
DOI : 10.4014/jmb.0909.09041
Ceramide is important not only for the maintenance of the barrier function of the skin but also for the water-binding capacity of the stratum corneum. Although the exact role of ceramide in the human skin is not fully understood, ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries. Compared with other microorganisms, yeast is more suitable for the production of ceramide because yeast grows fast and is non-toxic. However, production of ceramide from yeast has not been widely studied and most work in this area has been carried out using Saccharomyces cerevisiae. Regulating the genes that are involved in sphingolipid synthesis is necessary to increase ceramide production. In this study, we investigated the effect of the genes involved in the synthesis of ceramide, lcb1, lcb2, tsc10, lac1, lag1, and sur2, on ceramide production levels. The genes were cloned into pYES2 high copy number vectors. S. cerevisiae was cultivated on YPDG medium at
. Ceramide was purified from the cell extracts by solvent extraction and the ceramide content was analyzed by HPLC using ELSD. The maximum production of ceramide (9.8 mg ceramide/g cell) was obtained when the tsc10 gene was amplified by the pYES2 vector. Real-time RT-PCR analysis showed that the increase in ceramide content was proportional to the increase in the tsc10 gene expression level, which was 4.56 times higher than that of the control strain.
Microbial Quality and Safety of Fresh-Cut Broccoli with Different Sanitizers and Contact Times
Das, Basanta Kumar ; Kim, Ji-Gang ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 363~369
DOI : 10.4014/jmb.0907.07009
This study was conducted to investigate the effects of different sanitizers and contact times on storage quality and microbial growth in fresh-cut broccoli. Fresh broccoli samples were cut into small pieces, washed each for 90 s and 180 s in normal tap water (TW),
chlorinated water (CL, pH 7), electrolyzed water (EW, pH 7.2) containing
free chlorine, or
ozonated water (
). Then, samples were packaged in 30-
polyethylene bags and stored at
for 9 days. No significant differences were observed in gas composition and color parameters (
, and hue angle) among different sanitizers with contact times. No off-odor was detected during the storage. A longer contact time was not effective in reducing microbial population, except with
with 90 s was not much effective in reducing microbial population compared with Cl or EW. However, samples washed with
for 180 s observed the lowest numbers of total aerobic and coliform plate counts. The result suggested that, a longer contact time of ozone can be used as a potential sanitizer to maintain the microbial quality and safety of fresh-cut broccoli.
Cloning of aprE86-1 Gene Encoding a 27-kDa Mature Fibrinolytic Enzyme from Bacillus amyloliquefaciens CH86-1
Lee, Ae-Ran ; Kim, Gyoung-Min ; Kwon, Gun-Hee ; Lee, Kang-Wook ; Park, Jae-Yong ; Chun, Ji-Yeon ; Cha, Jae-Ho ; Song, Young-Sun ; Kim, Jeong-Hwan ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 370~374
DOI : 10.4014/jmb.0906.06029
A gene encoding the major secreted fibrinolytic protein of Bacillus amyloliquefaciens CH86-1 was cloned from genomic DNAs. DNA sequencing showed that the gene, aprE86-1, could direct the synthesis of a mature protein 275 amino acids in length after processing. When aprE86-1 was introduced into B. subtilis, a mature 27-kDa protein was produced as expected. The fibrinolytic activity of the B. subtilis transformant (TF) was higher than that of B. amyloliquefaciens CH86-1, showing the possibility of increasing the fibrinolytic activity of Bacillus strains through genetic engineering.
Development of a Highly Efficient Protein-Secreting System in Recombinant Lactobacillus casei
Kajikawa, Akinobu ; Ichikawa, Eiko ; Igimi, Shizunobu ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 375~382
DOI : 10.4014/jmb.0907.07032
The available techniques for heterologous protein secretion in Lactobacillus strains are limited. The aim of the present study was to develop an efficient protein-secretion system using recombinant lactobacilli for various applications such as live delivery of biotherapeutics. For the construction of expression vectors, the Lactobacillus brevis slpA promoter, Lactobacillus casei prtP signal sequence, and mouse IL-10 sequences were used as a model system. Interestingly, the slpA promoter exhibited strong activity in L. casei, contrary to previous observations. In order to stabilize replication of the plasmid in E. coli, a removable terminator sequence was built into the promoter region. For the improvement of secretion efficiency, a DTNSD oligopeptide was added to the cleavage site of signal peptidase. The resulting plasmids provided remarkably efficient IL-10 secretion. Accumulation of the protein in the culture supernatant varied widely according to the pH conditions. By analysis of the secreted protein, formation of homodimers, and biological activity, IL-10 was confirmed to be functional. The presently constructed plasmids could be useful tools for heterologous protein secretion in L. casei.
A Newly Isolated Rhizopus microsporus var. chinensis Capable of Secreting Amyloytic Enzymes with Raw-Starch-Digesting Activity
Li, Yu-Na ; Shi, Gui-Yang ; Wang, Wu ; Wang, Zheng-Xiang ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 383~390
DOI : 10.4014/jmb.0907.07025
A newly isolated active producer of raw-starch-digesting amyloytic enzymes, Rhizopus microsporus var. chinensis CICIM-CU F0088, was screened and identified by morphological characteristics and molecular phylogenetic analyses. This fungus was isolated from the soil of Chinese glue pudding mill, and produced high levels of amylolytic activity under solid-state fermentation with supplementation of starch and wheat bran. Results of thin-layer chromatography showed there are two kinds of amyloytic enzymes formed by this strain, including one
-amylase and two glucoamylases. It was found in the electron microscope experiments that the two glucoamylases can digest raw corn starch and have an optimal temperature of
. These results signified that amyloytic enzymes secreted by strain Rhizopus microsporus var. chinensis CICIM-CU F0088 were types of thermostable amyloytic enzymes and able to digest raw corn starch.
Prevalence and Quantification of Vibrio parahaemolyticus in Raw Salad Vegetables at Retail Level
Tunung, R. ; Margaret, S.P. ; Jeyaletchumi, P. ; Chai, L.C. ; Zainazor, T.C. Tuan ; Ghazali, F.M. ; Nakaguchi, Y. ; Nishibuchi, M. ; Son, R. ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 391~396
DOI : 10.4014/jmb.0908.08009
The purpose of this study was to investigate the biosafety of Vibrio parahaemolyticus in raw salad vegetables at wet markets and supermarkets in Malaysia. A combination of the most probable number-polymerase chain reaction (MPN-PCR) method was applied to detect the presence of V. parahaemolyticus and to enumerate their density in the food samples. The study analyzed 276 samples of common vegetables eaten raw in Malaysia (Wild cosmos=8; Japanese parsley=21; Cabbage=30; Lettuce=16; Indian pennywort=17; Carrot=31; Sweet potato=29; Tomato=38; Cucumber=28; Four-winged bean=26; Long bean=32). The samples were purchased from two supermarkets (A and B) and two wet markets (C and D). The occurrence of V. parahaemolyticus detected was 20.65%, with a higher frequency of V. parahaemolyticus in vegetables obtained from wet markets (Wet market C=27.27%; Wet Market D=32.05%) compared with supermarkets (Supermarket A=1.64%; Supermarket B=16.67%). V. parahaemolyticus was most prevalent in Indian pennywort (41.18%). The density of V. parahaemolyticus in all the samples ranged from <3 up to >2,400 MPN/g, mostly <3 MPN/g concentration. Raw vegetables from wet markets contained higher levels of V. parahaemolyticus compared with supermarkets. Although V. parahaemolyticus was present in raw vegetables, its numbers were low. The results suggest that raw vegetables act as a transmission route for V. parahaemolyticus. This study will be the first biosafety assessment of V. parahaemolyticus in raw vegetables in Malaysia.
Pedobacter xinjiangensis sp. nov., from the Desert, Xinjiang
Tang, Yali ; Wang, Yang ; Ji, Shanming ; Zhang, Kundi ; Dai, Jun ; Zhang, Lei ; Peng, Fang ; Fang, Chengxiang ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 397~402
DOI : 10.4014/jmb.0906.06036
A Gram-negative, rod-shaped, gliding, aerobic bacterium, designated
, was isolated from the desert of Xinjiang, China and subjected to a polyphasic taxonomic study. The strain
grew optimally at pH 7.0 and
. MK-7 was the predominant respiratory menaquinone. The DNA G+C content was 42.0 mol%. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the isolate was mostly related to members of the genus Pedobacter, with similarities ranging from 90.0% to 93.7%. Phylogenetic evidence and the results of phenotypic and genotypic analyses support the establishment of a novel species, Pedobacter xinjiangensis sp. nov., with strain
) as the type strain.
Saccharomyces cerevisiae Hsp30 is Necessary for Homeostasis of a Set of Thermal Stress Response Functions
Thakur, Suresh ; Chakrabarti, Amitabha ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 403~409
DOI : 10.4014/jmb.0907.07035
Saccharomyces cerevisiae Hsp30 is a plasma membrane heat shock protein that is induced by various environmental stress conditions. However, the functional role of Hsp30 during diverse environmental stressors is not presently known. To gain insight into its function during thermal stress, we have constructed and characterized a
strain during heat stress.
cells were found to be more sensitive compared with BY4741 cells, when exposed to a lethal heat stress at
. When budding yeast is exposed to either heat shock or weak organic acid, it inhibits Pma1p activity. In this study, we measured the levels of Pma1p in mutant and Wt cells both during optimal temperature and heat shock temperature. We observed that
cells showed constitutive reduction of Pma1p. To gain further insights into the role of Hsp30 during heat stress, we compared the total protein profile by 2D gel electrophoresis followed by identification of differentially expressed spots by LC-MS. We observed that contrary to that expected from thermal-stress-induced changes in gene expression, the
mutant maintained elevated levels of Pdc1p, Trx1p, and Nbp35p and reduced levels of Atp2p and Sod1p during heat shock. In conclusion, Hsp30 is necessary during lethal heat stress, for the maintenance of Pma1p and a set of thermal stress response functions.
Cohnella damensis sp. nov., a Motile Xylanolytic Bacteria Isolated from a Low Altitude Area in Tibet
Luo, Xuesong ; Wang, Zhang ; Dai, Jun ; Zhang, Lei ; Fang, Chengxiang ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 410~414
DOI : 10.4014/jmb.0903.03023
A bacterial strain, 13-
with xylanolytic activity isolated from a single soil sample, was characterized with respect to its phenetic and phylogenetic characteristics. The cells of the isolate are Gram-staining variable rods, but spore formation was not observed. This strain is catalase- and oxidase-positive, and able to degrade starch and xylan. The predominant fatty acids are anteiso-
, and iso-
. The major respiratory quinone is menaquinone 7(MK-7), with a polar lipid profile consistent with the genus Cohnella. The DNA G+C content is 54.3 mol%. The 168 rRNA gene sequence analysis indicates that this organism belongs to the genus Cohnella, with Cohnella panacarvi as the closest phylogenetic neighbor. Low levels of 168 rRNA gene sequence similarity (<97.0%) with respect to other taxa with published names and the identification of distinctive phenetic features in the isolate indicate that the strain 13-
represents a novel species of the genus Cohnella, for which the name Cohnella damensis sp. novo is proposed. The type strain is 13-
Omics-Based Analysis of the luxS Mutation in a Clinical Isolate of Escherichia coli O157:H7 in Korea
Kim, Jong-Chul ; Yoon, Jang-Won ; Kim, Jong-Bae ; Oh, Kyung-Hwan ; Park, Mi-Sun ; Lee, Bok-Kwon ; Cho, Seung-Hak ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 415~424
DOI : 10.4014/jmb.0904.04007
The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:87. A nonpolar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the
mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxisrelated genes (flhD; fliA, C, D, S, Z; and cheA, Y, Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.
mecA Gene Transferrability and Antibiogram of Zoonotic Staphylococcus intermedius from Animals, Staff, and the Environment in Animal Hospitals in Korea
Youn, Jung-Ho ; Hwang, Sun-Young ; Kim, So-Hyun ; Koo, Hye-Cheong ; Shin, Sook ; Moon, Bo-Youn ; Lim, Suk-Kyung ; Park, Yong-Ho ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 425~432
DOI : 10.4014/jmb.0905.05041
Staphylococcus intermedius is a common cause of otitis externa, pyoderma, and wound infections in companion animals. Although S. intermedius infections are rare in humans, it is zoonotic, with several case reports describing fatal human infections. Presently, we sought to isolate S. intermedius strains from various sources at animal hospitals nationwide in Korea, examine their antibiotic susceptibilities, and determine the possibility of horizontal transmission between animals and humans. Pulsed-field gel electrophoresis (pFGE) was used to compare the mecA gene in S. intermedius strains from humans, animals, and the environment in animal hospitals. A total of 119 S. intermedius strains were isolated from 529 samples. Using the disk diffusion method, over 90% of the isolates were found to be susceptible to cephalothin, amoxicillin-clavulanic acid, vancomycin, imipenem, nitroflurantoin, and amikacin, whereas 97.5% and 98.3% of the isolates were resistant to penicillin and ampicillin, respectively. Among the 39 S. intermedius strains harboring mecA, similar PFGE patterns were observed between seven isolates from an animal, two isolates from veterinary staff, and the environment in one animal hospital, and single isolates from an animal and a veterinarian at another hospital. This result suggests the possibility of horizontal transmission of S. intermedius containing mecA between humans, animals, and the environment in animal hospitals and also emphasizes on the importance of S. intermedius with mecA as a possible emerging threat to public health.
Cell Cycle Arrest and Cytochrome c-mediated Apoptotic Induction in A549 Human Lung Cancer Cells by MCS-C2, an Analog of Sangivamycin
Kang, Jeong-Hwa ; Lee, Dong-Keun ; Lee, Chul-Hoon ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 433~437
DOI : 10.4014/jmb.0910.10010
In the course of screening for novel modulators of cell cycle progression and apoptosis as anticancer drug candidates, we generated an analog of sangivamycin, MCS-C2, which was elucidated as 4-amino-6-bromo-7-cyclopentyl-7H-pyrrolo[2,3-d]pyrimidine-5-carboxamide. In the present study, we evaluated the molecular mechanisms of MCSC2-induced cell cycle arrest and apoptosis in A549 human lung cancer cells. To investigate the effects of MCS-C2 on cell cycle progression in A549 cells, we measured the DNA content of A549 cells treated with
MCS-C2 using flow cytometry. The analysis revealed an appreciable
phase arrest in treated cells. This event was associated with significant upregulation of p53 and
. In addition, the TUNEL assay was used to examine apoptotic induction in treated cells, and the effects of MCS-C2 on the expression of apoptosis-associated proteins were examined by Western blot. Apoptotic induction in MCS-C2-treated A549 cells was associated with cytochrome c release from mitochondria, which in turn resulted in the activation of caspase-9 and -3 and the cleavage of poly(ADP-ribose) polymerase (PARP). Based on these results, we conclude that MCS-C2 is a candidate therapeutic agent for the treatment of human lung cancer via upregulation and activation of p53.
Immunomodulatory Effects of Aureobasidium pullulans SM-2001 Exopolymers on Cyclophosphamide-Treated Mice
Yoon, Hyun-Soo ; Kim, Joo-Wan ; Cho, Hyung-Rae ; Moon, Seung-Bae ; Shin, Hyun-Dong ; Yang, Kun-Ju ; Lee, Hyeung-Sik ; Kwon, Young-Sam ; Ku, Sae-Kwang ;
Journal of Microbiology and Biotechnology, volume 20, issue 2, 2010, Pages 438~445
DOI : 10.4014/jmb.0905.05058
The immunomodulatory effects of Aureohasidium pullulans SM-2001 exopolymers containing
-1,3/1,6-glucan were evaluated in cyclophosphamide (CPA)-treated mice. To induce immunosuppression, 150 and 110 mg/kg of CPA were intraperitoneally injected 3 days and 1 day, respectively, before beginning administration of the test material. Exopolymers were delivered subcutaneously or orally, four times, in a volume of 10 ml/kg at 12-h intervals beginning 24 h after the second CPA treatment. Changes in thymus and spleen weights, splenic amounts of tumor necrosis factor (TNF)-
, interleukin (IL)-
, and IL-10, and numbers of CD3+, CD4+, CD8+, and TNF-
thymus and spleen cells were monitored in CPA-treated mice. As a result of CPA treatment, dramatic decreases in the number of CD3+, CD4+, CD8+, and TNF-
cells were detected in the thymus and spleen, along with decreases in thymus and spleen weights. In addition, splenic TNF-
, and IL-10 contents were also decreased on observation with flow cytometry. However, oral and subcutaneous treatments with exopolymers effectively reduced the immunosuppressive changes induced by CPA. Therefore, it is concluded that exopolymers of A. pullulans SM-2001 can effectively prevent immunosuppression through, at least partially, the recruitment of T cells and TNF-
cells or enhancement of their activity, and can provide an effective component of prevention or treatment regimens for immunosuppression related to cancer, sepsis, and high-dose chemotherapy or radiotherapy.