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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 19, Issue 12 - Dec 2009
Volume 19, Issue 11 - Nov 2009
Volume 19, Issue 10 - Oct 2009
Volume 19, Issue 9 - Sep 2009
Volume 19, Issue 8 - Aug 2009
Volume 19, Issue 7 - Jul 2009
Volume 19, Issue 6 - Jun 2009
Volume 19, Issue 5 - May 2009
Volume 19, Issue 4 - Apr 2009
Volume 19, Issue 3 - Mar 2009
Volume 19, Issue 2 - Feb 2009
Volume 19, Issue 1 - Jan 2009
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Fungal Diversity in Composting Process of Pig Manure and Mushroom Cultural Waste Based on Partial Sequence of Large Subunit rRNA
Cho, Kye-Man ; Kwon, Eun-Ju ; Kim, Sung-Kyum ; Kambiranda, Devaiah M ; Math, Reukaradhya K ; Lee, Young-Han ; Kim, Jung-Ho ; Yun, Han-Dae ; Kim, Hoon ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 743~748
DOI : 10.4014/jmb.0807.455
Fungal diversity during composting was investigated by culture-independent rDNA sequence analysis. Composting was carried out with pig manure and mushroom cultural waste using a field-scale composter (Hazaka system), and samples were collected at various stages. Based on partial sequence analysis of large subunit (LSU) ribosomal RNA (rRNA) and sequence identity values, a total of 12 different fungal species were found at six sampling sites; Geotrichum sp., Debaryomyces hansenii, Monographella nivalis, Acremonium strictum, Acremonium alternatum, Cladosporium sphaerospermum, Myriangium durosai, Pleurotus eryngii, Malassezia globosa, Malassezia restricta, Rhodotorula glutinis, and Fusarium sporotrichioides. Geotrichum sp. of the class Saccharomycetes was the most predominant fungal species throughout the composting process (185 out of a total of 236 identified clones, or 78.4%), followed by Acremonium strictum (7.6%), Monographella nivalis (5.1%), and Pleurotus eryngii (3.8%). The prevalence of Geotrichum sp. was the lowest (61.1%) at the beginning of composting, and then gradually increased to 92.5% after 10 days of composting.
Diversity of Bacillus thuringiensis Strains Isolated from Citrus Orchards in Spain and Evaluation of Their Insecticidal Activity Against Ceratitis capitata
J.C., Vidal-Quist ; Castanera, P. ; Gonzalez-Cabrera, J. ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 749~759
DOI : 10.4014/jmb.0810.595
A survey of Bacillus thuringiensis (Berliner) strains isolated from Spanish citrus orchards has been performed, and the strains were tested for insecticidal activity against the Mediterranean fruit fly Ceratitis capitata (Wiedemann), a key citrus pest in Spain. From a total of 150 environmental samples, 376 isolates were selected, recording a total B. thuringiensis index of 0.52. The collection was characterized by means of phase-contrast microscopy, SDS-PAGE, and PCR analysis with primer pairs detecting toxin genes cry1, cry2, cry3, cry4, cry5, cry7, cry8, cry9, cry10, cry11, cry12, cry14, cry17, cry19, cry21, cry27, cry39, cry44, cyt1, and cyt2. Diverse crystal inclusion morphologies were identified: bipyramidal (45%), round (40%), adhered to the spore (7%), small (5%), and irregular (3%). SDS-PAGE of spore-crystal preparations revealed 39 different electrophoresis patterns. All primer pairs used in PCR tests gave positive amplifications in strains of our collection, except for primers for detection of cry3, cry19, cry39, or cry44 genes. Strains containing cry1, cry2, cry4, and cry27 genes were the most abundant (48.7%, 46%, 11.2%, and 8.2% of the strains, respectively). Ten different genetic profiles were found, although a total of 109 strains did not amplify with the set of primers used. Screening for toxicity against C. capitata adults was performed using both spore-crystal and soluble fractions. Mortality levels were less than 30%. We have developed a large and diverse B. thuringiensis strain collection with huge potential to control several agricultural pests; however, further research is needed to find out Bt strains active against C. capitata.
An In Vitro Study of the Antifungal Effect of Silver Nanoparticles on Oak Wilt Pathogen Raffaelea sp.
Kim, Sang-Woo ; Kim, Kyoung-Su ; Lamsal, Kabir ; Kim, Young-Jae ; Kim, Seung-Bin ; Jung, Moo-Young ; Sim, Sang-Jun ; Kim, Ha-Sun ; Chang, Seok-Joon ; Kim, Jong-Kuk ; Lee, Youn-Su ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 760~764
DOI : 10.4014/jmb.0812.649
In this study, we investigated the antifungal activity of three different forms of silver nanoparticles against the unidentified ambrosia fungus Raffaelea sp., which has been responsible for the mortality of a large number of oak trees in Korea. Growth of fungi in the presence of silver nanoparticles was significantly inhibited in a dose-dependent manner. We also assessed the effectiveness of combining the different forms of nanoparticles. Microscopic observation revealed that silver nanoparticles caused detrimental effects not only on fungal hyphae but also on conidial germination.
Regulation of the Edwardsiella tarda Hemolysin Gene and luxS by EthR
Fang, Wang ; Zhang, Min ; Hu, Yong-Hua ; Zhang, Wei-wei ; Sun, Li ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 765~773
DOI : 10.4014/jmb.0810.574
Edwardsiella tarda is a pathogen with a broad host range that includes human and animals. The E. tarda hemolysin (Eth) system, which comprises EthA and EthB, is a noted virulence element that is widely distributed in pathogenic isolates of E. tarda. Previous study has shown that the expression of ethB is regulated by iron, which suggests the possibility that the ferric uptake regulator (Fur) is involved in the regulation of ethB. The work presented in this report supports the previous findings and demonstrates that ethB expression was decreased under conditions when the E. tarda Fur (
) was overproduced, and enhanced when
was inactivated. We also identified a second ethB regulator, EthR, which is a transcription regulator of the GntR family. EthR represses ethB expression by direct interaction with the ethB promoter region. In addition to ethB, EthR also modulates, but positively, luxS expression and AI-2 production by binding to the luxS promoter region. The expression of ethR itself is subject to negative autoregulation; interference with this regulation by overexpressing ethR during the process of infection caused (i) drastic changes in ethB and luxS expressions, (ii) vitiation in the tissue dissemination and survival ability of the bacterium, and (iii) significant attenuation of the overall bacterial virulence. These results not only provide new insights into the regulation mechanisms of the Eth hemolysin and LuxS/AI-2 quorum sensing systems but also highlight the importance of these systems in bacterial virulence.
Comparative Analysis of Expressed Sequence Tags from Flammulina velutipes at Different Developmental Stages
Joh, Joong-Ho ; Kim, Kyung-Yun ; Lim, Jong-Hyun ; Son, Eun-Suk ; Park, Hye-Ran ; Park, Young-Jin ; Kong, Won-Sik ; Yoo, Young-Bok ; Lee, Chang-Soo ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 774~780
DOI : 10.4014/jmb.0809.548
Flammulina velutipes is a popular edible basidiomycete mushroom found in East Asia and is commonly known as winter mushroom. Mushroom development showing dramatic morphological changes by different environmental factors is scientifically and commercially interesting. To create a genetic database and isolate genes regulated during mushroom development, cDNA libraries were constructed from three developmental stages of mycelium, primordium, and fruit body in F. velutipes. We generated a total of 5,431 expressed sequence tags (ESTs) from randomly selected clones from the three cDNA libraries. Of these, 3,332 different unique genes (unigenes) were consistent with 2,442 (73%) singlets and 890 (27%) contigs. This corresponds to a redundancy of 39%. Using a homology search in the gene ontology database, the EST unigenes were classified into the three categories of molecular function (28%), biological process (29%), and cellular component (6%). Comparative analysis found great variations in the unigene expression pattern among the three different unigene sets generated from the cDNA libraries of mycelium, primordium, and fruit body. The 19-34% of total unigenes were unique to each unigene set and only 3% were shared among all three unigene sets. The unique and common representation in F. velutipes unigenes from the three different cDNA libraries suggests great differential gene expression profiles during the different developmental stages of F. velutipes mushroom.
Enhanced Delivery of siRNA Complexes by Sonoporation in Transgenic Rice Cell Suspension Cultures
Cheon, Su-Hwan ; Lee, Kyoung-Hoon ; Kwon, Jun-Young ; Choi, Sung-Hun ; Song, Mi-Na ; Kim, Dong-II ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 781~786
DOI : 10.4014/jmb.0901.057
Small interfering synthetic double-stranded RNA (siRNA) was applied to suppress the expression of the human cytotoxic-T-Iymphocyte antigen 4-immunoglobulin (hCTLA4Ig) gene transformed in transgenic rice cell cultures. The sequence of the 21-nucleotide siRNA was deliberately designed and synthesized with overhangs to inactivate the expression of hCTLA4Ig. The chemically synthesized siRNA duplex was combined with polyethyleneimine (PEl) at a mass ratio of 1:10 (0.33
PEl) to produce complexes. The siRNA complexes (siRNA+PEI) were labeled with Cy3 in order to subsequently confirm the delivery by fluorescent microscopy. In addition, the cells were treated with sonoporation at 40 kHz and 419W for 90 s to improve the delivery. The siRNA complexes alone inhibited the expression of hCTLA4Ig to 45% compared with control. The siRNA complexes delivered with sonoporation downregulated the production of hCTLA4Ig to 73%. Therefore, we concluded that the delivery of siRNA complexes into plant cells could be enhanced successfully by sonoporation.
Heptelidic Acid, a Sesquiterpene Lactone, Inhibits Etoposide-Induced Apoptosis in Human Leukemia U937 Cells
Kim, Jin-Hee ; Lee, Choong-Hwan ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 787~791
DOI : 10.4014/jmb.0810.585
In the course of screening for substances that inhibit etoposide (10
/ml)-induced apoptosis in human leukemia U937 cells, fungal strain F000120, which exhibits potent inhibitory activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak
column chromatography and HPLC, and was identified as heptelidic acid (koningic acid) by spectroscopic methods. This compound inhibited caspase-3 induction in U937 cells with an
value of 40
after 8 h of etoposide treatment. Fluorescent dye staining with acridine orange and ethidium bromide showed that heptelidic acid inhibited apoptosis. Furthermore, it was found that DNA fragmentation and caspase-3 activation, the biological hallmarks of apoptosis, were inhibited by the compound in a dose-dependent manner, suggesting that heptelidic acid inhibits etoposide-induced apoptosis via downregulation of caspases.
Identification of Novel Bioactive Hexapeptides Against Phytopathogenic Bacteria Through Rapid Screening of a Synthetic Combinatorial Library
Choi, Jae-Hyuk ; Moon, Eun-Pyo ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 792~802
DOI : 10.4014/jmb.0809.497
Antimicrobial peptides (AMPs) are considered to be a promising alternative to conventional antibiotics for future generations. We identified four novel hexapeptides with antimicrobial activity: KCM11 (TWWRWW-
), KCM12 (KWRWlW-
), KCM21 (KWWWRW-
), and KRS22 (WRWFIH-
), through positional scanning of a synthetic peptide combinatorial library (PS-SCL). The ability of these peptides to inhibit the growth of a variety of bacteria and unicellular fungi was evaluated. KCM11 and KRS22 preferentially inhibited the normal growth of fungal strains, whereas KCM12 and KCM21 were more active against bacterial strains. Bactericidal activity was addressed in a clear zone assay against phytopathogenic bacteria, including Pectobacterium spp., Xanthomonas spp., Pseudomonas spp., etc. KCM21 showed the highest activity and was effective against a wide range of target organisms. Application of KCM21 with inoculation of Pectobacterium carotovorum subsp. carotovorum on detached cabbage leaves resulted in an immune phenotype or a significant reduction in symptom development, depending on the peptide concentration. Cytotoxicity of the four hexapeptides was evaluated in mouse and human epithelial cell lines using an MTT test. The results revealed a lack of cytotoxic effects.
Baicalein Induces Programmed Cell Death in Candida albicans
Dai, Bao-Di ; Cao, Ying-Ying ; Huang, Shan ; Xu, Yong-Gang ; Gao, Ping-Hui ; Wang, Yan ; Jiang, Yuan-Ying ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 803~809
DOI : 10.4014/jmb.0812.662
Recent evidence has revealed the occurrence of an apoptotic phenotype in Candida albicans that is inducible with environmental stresses such as acetic acid, hydrogen peroxide, and amphotericin B. In the present study, we found that the Chinese herbal medicine Baicalein (BE), which was one of the skullcapflavones, can induce apoptosis in C. albicans. The apoptotic effects of BE were detected by flow cytometry using Annexin V-FITC and DAPI, and it was confirmed by transmission electron microscopy analysis. After exposure to 4
/ml BE for 12 h, about 10% of C. albicans cells were apoptotic. Both the increasing intracellular levels of reactive oxygen species (ROS) and upregulation of some redox-related genes (CAP1, SOD2, TRR1) were observed. Furthermore, we compared the survivals of CAP1 deleted, wild-type, and overexpressed strains and found that Cap1p attenuated BE-initiated cell death, which was coherent with a higher mRNA level of the CAP1 gene. In addition, the mitochondrial membrane potential of C. albicans cells changed significantly (p<0.001) upon BE treatment compared with control. Taken together, our results indicated that BE treatment induced apoptosis in C. albicans cells, and the apoptosis was associated with the breakdown of mitochondrial membrane potential.
Effect of Protective Compounds on the Survival, Electrolyte Leakage, and Lipid Degradation of Freeze-Dried Weissella paramesenteroides LC11 During Storage
Yao, Amenan A. ; Wathelet, Bernard ; Thonart, Philippe ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 810~817
DOI : 10.4014/jmb.0809.553
The effect of cryoprotectants (maltodextrin+glycerol) and cryoprotectants+antioxidant [ascorbic acid and/or butylated hydroxytoluene (BHT)] mixtures on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage was investigated and compared with that of the control (cells without additives) over a 90-day storage period at 4 or
in glass tubes with water activity (
) of 0.23. The survival, electrolyte leakage, and lipid degradation were evaluated through colony counts, electrical conductivity, and thiobarbituric acid reactive substances (TBARS) content, respectively. The fatty acids composition was determined by gas chromatography, in both the total lipid extract and the polar lipid fraction, and compared with that of the control after the 90-day storage period. As the storage proceeded, increases in leakage value and TBARS content, as well as a decrease in viability, were observed. After 90 days of storage, the major fatty acids found in both the total lipid extract and the polar lipid fraction were palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids. The survival, leakage value, TBARS content and 18:2/16:0 or 18:3/16:0 ratio were the greatest for the protected strain held at
. Cells with the cryoprotectants+BHT mixture showed the highest percentage of survival and 18:2/16:0 or 18:3/16:0 ratio in both lipid extracts, as well as the lowest leakage value and TBARS content after the 90-day storage period. Drying cells with the cryoprotectants+BHT mixture considerably slowed down polar lipid degradation and loss of membrane integrity, resulting in improved viability during storage.
Purification and Characterization of a Thermostable
,3-1,4-Glucanase from Laetiporus sulphureus var. miniatus
Hong, Mi-Ri ; Kim, Yeong-Su ; Joo, Ah-Reum ; Lee, Jung-Kul ; Kim, Yeong-Suk ; Oh, Deok-Kun ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 818~822
DOI : 10.4014/jmb.0812.674
,3-1,4-glucanase from the fungus Laetiporus sulphureus var. miniatus was purified as a single 26 kDa band by ammonium sulfate precipitation, HiTrap Q HP, and UNO Q ion-exchange chromatography, with a specific activity of 29 U/mg. The molecular mass of the native enzyme was 52 kDa as a dimer by gel filtration.
,3-1,4-Glucanase showed optimum activity at pH 4.0 and
. The half-lives of the enzyme at
were 152 h and 22 h, respectively. The enzyme showed the highest activity for barley
,3-1,4-glucan among the tested polysaccharides and p-nitrophenyl-
-D-glycosides with a
, of 0.67 mg/ml, a
of 20 mg/ml/s.
Molecular Cloning and Expression of the Trichoderma harzianum C4 Endo-
,4-Xylanase Gene in Saccharomyces cerevisiae
Lee, Jung-Min ; Shin, Ji-Won ; Nam, Jae-Kook ; Choi, Ji-Young ; Jeong, Choon-Soo ; Han, In-Seob ; Nam, Soo-Wan ; Choi, Yun-Jaie ; Chung, Dae-Kyun ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 823~828
DOI : 10.4014/jmb.0810.577
-xylanase) from Trichoderma harzianum C4 was purified without cellulase activity by sequential chromatographies. The specific activity of the purified enzyme preparation was 430 units/mg protein on D-xylan. The complementary DNA (cDNA) encoding
-xylanase (xynII) was amplified by PCR and isolated from cDNA PCR libraries constructed from T. harzianum C4. The nucleotide sequence of the cDNA fragment contained an open reading frame of 663 bp that encodes 221 amino acids, of which the mature protein is homologous to several
-xylanases II. An intron of 63 bp was identified in the genomic DNA sequence of xynII. This gene was expressed in Saccharomyces cerevisiae strains under the control of adh1 (alcohol dehydrogenase I) and pgk1 (phosphoglycerate kinase I) promoters in 2
-based plasmids, which could render recombinants able to secrete
-xylanase into the media.
Cloning of Dextransucrase Gene from Leuconostoc citreum HJ-P4 and Its High-Level Expression in E. coli by Low Temperature Induction
Yi, Ah-Rum ; Lee, So-Ra ; Jang, Myoung-Uoon ; Park, Jung-Mi ; Eom, Hyun-Ju ; Han, Nam-Soo ; Kim, Tae-Jip ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 829~835
DOI : 10.4014/jmb.0812.683
A dextransucrase (LcDS) gene from Leuconostoc citreum HJ-P4 has been amplified and cloned in E. coli. The LcDS gene consists of 4,431 nucleotides encoding 1,477 amino acid residues sharing 63-98% of amino acid sequence identities with other known dextransucrases from Leuc. mesenteroides. Interestingly, 0.1 mM of IPTG induction at
remarkably increased the LcDS productivity to 19,187 U/I culture broth, which was over 330-fold higher than that induced at
. Optimal reaction temperature and pH of LcDS were determined as
and pH 5.5 in 20 mM sodium acetate buffer, respectively. Meanwhile, 0.1 mM
increased its activity to the maximum of 686 U/mg, which was 2.1-fold higher than that in the absence of calcium ion. Similar to the native Leuconostoc dextransucrase, recombinant LcDS could successfully produce a series of isomaltooligosaccharides from sucrose and maltose, on the basis of its transglycosylation activity.
Electrochemical Activation of Nitrate Reduction to Nitrogen by Ochrobactrum sp. G3-1 Using a Noncompartmented Electrochemical Bioreactor
Lee, Woo-Jin ; Park, Doo-Hyun ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 836~844
DOI : 10.4014/jmb.0810.569
A denitrification bacterium was isolated from riverbed soil and identified as Ochrobactrum sp., whose specific enzymes for denitrification metabolism were biochemically assayed or confirmed with specific coding genes. The denitrification activity of strain G3-1 was proportional to glucose/nitrate balance, which was consistent with the theoretical balance (0.5). The modified graphite felt cathode with neutral red, which functions as a solid electron mediator, enhanced the electron transfer from electrode to bacterial cell. The porous carbon anode was coated with a ceramic membrane and cellulose acetate film in order to permit the penetration of water molecules from the catholyte to the outside through anode, which functions as an air anode. A non-compartmented electrochemical bioreactor (NCEB) comprised of a solid electron mediator and an air anode was employed for cultivation of G3-1 cells. The intact G3-1 cells were immobilized in the solid electron mediator, by which denitrification activity was greatly increased at the lower glucose/nitrate balance than the theoretical balance (0.5). Metabolic stability of the intact G3-1 cells immobilized in the solid electron mediator was extended to 20 days, even at a glucose/nitrate balance of 0.1.
Pretreatment on Corn Stover with Low Concentration of Formic Acid
Xu, Jian ; Thomsen, Mette Hedegaard ; Thomsen, Anne Belinda ;
Journal of Microbiology and Biotechnology, volume 19, issue 8, 2009, Pages 845~850
DOI : 10.4014/jmb.0809.514
Bioethanol derived from lignocellulosic biomass has the potential to replace gasoline. Cellulose is naturally recalcitrant to enzymatic attack, and it also surrounded by the matrix of xylan and lignin, which enhances the recalcitrance. Therefore, lignocellulosic materials must be pretreated to make the cellulose easily degraded into sugars and further fermented to ethanol. In this work, hydrothermal pretreatment on corn stover at
for 15 min with and without lower concentration of formic acid was compared in terms of sugar recoveries and ethanol fermentation. For pretreatment with formic acid, the overall glucan recovery was 89% and pretreatment without formic acid yielded the recovery of 94%. Compared with glucan, xylan was more sensitive to the pretreatment condition. The lowest xylan recovery of 55% was obtained after pretreatment with formic acid and the highest of 75% found following pretreatment without formic acid. Toxicity tests of liquor parts showed that there were no inhibitions found for both pretreatment conditions. After simultaneous saccharification and fermentation (SSF) of the pretreated corn stover with Baker's yeast, the highest ethanol yield of 76.5% of the theoretical was observed from corn stover pretreated at
for 15 min with formic acid.