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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Microbiology and Biotechnology
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 17, Issue 12 - Dec 2007
Volume 17, Issue 11 - Nov 2007
Volume 17, Issue 10 - Oct 2007
Volume 17, Issue 9 - Sep 2007
Volume 17, Issue 8 - Aug 2007
Volume 17, Issue 7 - Jul 2007
Volume 17, Issue 6 - Jun 2007
Volume 17, Issue 5 - May 2007
Volume 17, Issue 4 - Apr 2007
Volume 17, Issue 3 - Mar 2007
Volume 17, Issue 2 - Feb 2007
Volume 17, Issue 1 - Jan 2007
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Cancer Chemopreventive Effects of Lactic Acid Bacteria
Kim, Jong-Eun ; Kim, Ji-Yeon ; Lee, Ki-Won ; Lee, Hyong-Joo ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1227~1235
Lactic acid bacteria (LAB) provide several potential health and nutritional benefits, including improving the nutritional value of food, controlling serum cholesterol levels, and controlling some types of cancer. Numerous in vitro, in vivo, human, and epidemiological studies have provided evidence of the chemopreventive effects of LAB on colon, bladder, liver, breast, and gastric cancers. These effects act via diverse mechanisms, including alteration of the gastrointestinal micro flora, enhancement of the host's immune response, and antioxidative and antiproliferative activities. This review discusses the recent progresses on the chemopreventive effects of LAB on specific cancer types and the underlying molecular mechanisms.
Analysis of Factors Affecting the Periplasmic Production of Recombinant Proteins in Escherichia coli
Mergulhao, Filipe J. ; Monteiro, Gabriel A. ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1236~1241
Five fusion proteins between Z domains derived from Staphylococcal Protein A and Green Fluorescent Protein or Human Proinsulin were produced on the periplasm of Escherichia coli. The effects of the molecular weight and amino acid composition of the translocated peptide, culture medium composition, and growth phase of the bacterial culture were analyzed regarding the expression and periplasmic secretion of the recombinant proteins. It was found that secretion was not affected by the size of the translocated peptide (17-42 kDa) and that the highest periplasmic production values were obtained on the exponential phase of growth. Moreover, the highest periplasmic values were obtained in minimal medium, showing the relevance of the culture medium composition on secretion. In silico prediction analysis suggested that with respect to the five proteins used in this study, those that are prone to form
-helix structures are more translocated to the periplasm.
Critical Factors to High Thermostability of an
-Amylase from Hyperthermophilic Archaeon Thermococcus onnurineus NA1
Lim, Jae-Kyu ; Lee, Hyun-Sook ; Kim, Yun-Jae ; Bae, Seung-Seob ; Jeon, Jeong-Ho ; Kang, Sung-Gyun ; Lee, Jung-Hyun ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1242~1248
Genomic analysis of a hyperthermophilic archaeon, Thermococcus onnurineus NA1 , revealed the presence of an open reading frame consisting of 1,377 bp similar to
-amylases from Thermococcales, encoding a 458-residue polypeptide containing a putative 25-residue signal peptide. The mature form of the
-amylase was cloned and the recombinant enzyme was characterized. The optimum activity of the enzyme occurred at
and pH 5.5. The enzyme showed a liquefying activity, hydrolyzing maltooligosaccharides, amylopectin, and starch to produce mainly maltose (G2) to maltoheptaose (G7), but not pullulan and cyclodextrin. Surprisingly, the enzyme was not highly thermostable, with half-life (
) values of 10 min at
, despite the high similarity to
-amylases from Pyrococcus. Factors affecting the thermostability were considered to enhance the thermo stability. The presence of
seemed to be critical, significantly changing
to 153 min by the addition of 0.5 mM
. On the other hand, the thermostability was not enhanced by the addition of
or other divalent metals, irrespective of the concentration. The mutagenetic study showed that the recovery of zinc-binding residues (His175 and Cys189) enhanced the thermo stability, indicating that the residues involved in metal binding is very critical for the thermostability.
Analysis of Active Center in Hyperthermophilic Cellulase from Pyrococcus horikoshii
Kang, Hee-Jin ; Ishikawa, Kazuhiko ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1249~1253
A hyperthermostable endoglucanase from Pyrococcus horikoshii with the capability of hydrolyzing crystalline cellulose was analyzed. A protein engineering study was carried out to obtain a reduced-size mutant. Five amino acid residues at both the N- and C-terminus were found to be removable without any loss of activity or thermal stability. Site-directed mutagenesis was also performed on R102, N200, E201, H297, Y299, E342, and W377, residues possibly involved in the active center or in the recognition and binding of a cellulose substrate. The activity of the resulting mutants was considerably decreased, confirming that the mutated residues were all important for activity. A reduced-size enzyme, as active as the wild-type endoglucanase, was successfully obtained, plus the residues critical for its activity and specificity were confirmed. Consequently, an engineered enzyme with a reduced size was obtained, and the amino acids essential for activity were confirmed by site-directed mutagenesis and comparison with a known three-dimensional structure.
Detection of Nitrate/Nitrite Bioavailability in Wastewater Using a luxCDABE-Based Klebsiella oxytoca Bioluminescent Bioreporter
Abd-El-Haleem, Desouky ; Ripp, Steven ; Zaki, Sahar ; Sayler, Gary S. ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1254~1261
In the present study, we have constructed a bioluminescent bioreporter for the assessment of nitrate/nitrite bioavailability in wastewater. Specifically, an approximately 500-bp DNA fragment containing a nitrate/nitrite-activated nasR-like promoter (regulating expression of genes encoding nitrite reductase in the genus Klebsiella) was fused upstream of the Vibrio fischeri luxCDABE gene cassette in a modified mini-Tn5 vector. Characterization of this strain, designated W6-1, yielded dose-dependent increased bioluminescence coincident with increased nitrate, nitrite, and ammonium added to the growth medium from 1 to 11 ppm. Bioluminescence in response to nitrogen species addition was light dependent up to 10, 7, and 8 ppm with nitrate, nitrite, and ammonium, respectively. This response was linear in the range from 1 to 8 ppm for nitrate (
), 1 to 6 ppm for nitrite (
), and 1 to 7 ppm for ammonium (
). A significant bioluminescent response was also recorded when strain W6-1 was incubated with slurries from aged, nitrate/nitrite contaminated wastewater. Thus, bioreporter strain W6-1 can be used to elucidate factors that constrain the use of nitrate/nitrite in wastewaters.
Evaluation of Arabinofuranosidase and Xylanase Activities of Geobacillus spp. Isolated from Some Hot Springs in Turkey
Sabriye, Canakci ; Inan, Kadriye ; Murat, Kacagan ; Belduz, Ali Osman ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1262~1270
Some hot springs located in the west of Turkey were investigated with respect to the presence of thermophilic microorganisms. Based on phenotyping characteristics and 16S rRNA gene sequence analysis, 16 of the isolates belonged to the genus Geobacillus and grew optimally at about
on nutrient agar. 16S rRNA gene sequence analysis showed that these isolates resembled Geobacillus species by
, but SDS-PAGE profiles of these 16 isolates differ from some of the other species of the genus Geobacillus. However, it is also known that analysis of 16S rRNA gene sequences may be insufficient to distinguish between some species. It is proposed that recN sequence comparisons could accurately measure genome similarities for the Geobacillus genus. Based on recN sequence analysis, isolates 11, IT3, and 12 are strains of G stearothermophilus; isolate 14.3 is a strain of G thermodenitrificans; isolates 9.1, IT4.1, and 4.5 are uncertain and it is required to make further analysis. The presence of xylanase and arabinofuranosidase activities, and their optimum temperature and pH were also investigated. These results showed that 7 of the strains have both xylanase and arabinofuranosidase activities, 4 of them has only xylanase, and the remaning 5 strains have neither of these activities. The isolates 9.1, 7.1, and 3.3 have the highest temperature optima (
), and 7.2, 9.1, AO4, 9.2, and AO17 have the highest pH optima (pH 8) of xylanase. Isolates 7.2, AO4, AC15, and 12 have optimum arabinofuranosidase activities at
, and only isolate AC15 has the lowest pH of 5.5.
Purification, Characterization, and Cloning of Fibrinolytic Metalloprotease from Pleurotus ostreatus Mycelia
Shen, Ming-Hua ; Kim, Jae-Sung ; Sapkota, Kumar ; Park, Se-Eun ; Choi, Bong-Suk ; Kim, Seung ; Lee, Hyun-Hwa ; Kim, Chun-Sung ; Chun, Hong-Sung ; Ryoo, Cheon-In ; Kim, Sung-Jun ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1271~1283
A fibrinolytic protease (PoFE) was purified from the cultured mycelia of the edible oyster mushroom Pleurotus ostreatus, using a combination of various chromatographies. The purification protocol resulted in an 876-fold purification of the enzyme, with a final yield of 6.5%. The apparent molecular mass of the purified enzyme was estimated to be 32 kDa by SDS-PAGE, fibrin-zymography, and size exclusion using FPLC. The optimal reaction pH value and temperature were pH 6.5 and
, respectively. PoFE effectively hydrolyzed fibrinogen, preferentially digesting the
-chain and the
-chain over the
-chain. Enzyme activity was enhanced by the addition of
ions. Furthermore, PoFE activity was potently inhibited by EDTA, and it was found to exhibit a higher specificity for the chromogenic substrate S-2586 for chymotrypsin, indicating that the enzyme is a chymotrypsin-like metalloprotease. The first 19 amino acid residues of the N-terminal sequence were ALRKGGAAALNIYSVGFTS, which is extremely similar to the metalloprotease purified from the fruiting body of P. ostreatus. In addition, we cloned the PoFE protein, encoding gene, and its nucleotide sequence was determined. The cDNA of cloned PoFE is 867 nucleotides long and consists of an open reading frame encoding 288 amino acid residues. Its cDNA showed a high degree of homology with PoMEP from P. ostreatus fruiting body. The mycelia of P. ostreatus may thus represent a potential source of new therapeutic agents to treat thrombosis.
Shelf-Life Extension of Fresh-Cut Iceberg Lettuce (Lactuca sativa L) by Different Antimicrobial Films
Kang, Sun-Chul ; Kim, Min-Jeong ; Choi, Ung-Kyu ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1284~1290
This study was conducted to investigate the antibacterial activity and shelf-life extension effect of iceberg lettuce packed in BN/PE film. The BN/PE film has a strong microbial suppression effect on pathogenic bacteria such as Escherichia coli, Salmonella enteritidis, and S. typhimurium. The number of psychrophiles and mesophiles during 5 days of cold storage of fresh-cut iceberg lettuce at
packaged in BN/PE film was strictly suppressed in comparison with other tested films (OPP, PE, and PET film). When fresh processed iceberg lettuce was processed and stored under the current conditions, the shelf-life of the product was longer than 5 days in the BN/PE film package, whereas the shelf-life when using the other films tested, PE, OPP and PET, was no longer than 3-4 days. The decay rates of the iceberg lettuce packed in the BN/PE film was maintained at
on the 5th day of preservation. The samples packed in BN/PE film maintained an excellent visual quality during the 3 days of storage without significant differences in comparison with the initial visual quality. No browning was observed in the samples packed in BN/PE film for up to 3 days. The texture of shredded iceberg lettuce packaged in BN/PE film remained unchanged up to 3 days, and then a moderate decrease in texture was observed after 4 days of storage. In addition, the overall acceptability of fresh-cut iceberg lettuce packaged in BN/PE film did not change for up to 3 days, whereas the samples packaged in the other films were inedible by 3 days of storage. In conclusion, the shelf-life of fresh-cut iceberg lettuce packaged in the BN/PE film was extended to more than 5 days at
, whereas that in the other films was 2 days at
. Therefore, the shelf-life extension effect of the fresh-cut iceberg lettuce in BN/PE film packaging was very effective compared with the other films tested.
Characterization and Action Patterns of Two
-1,4-Glucanases Purified from Cellulomonas uda CS1-1
Yoon, Min-Ho ; Choi, Woo-Young ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1291~1299
-1,4-glucanases (DI and DIII fractions) were purified to homogeneity from the culture filtrate of a cellulolytic bacteria, Cellulomonas sp. CS 1-1, which was classified as a novel species belonging to Cellulomonas uda based on chemotaxanomic and phylogenetic analyses. The molecular mass was estimated as 50,000 Da and 52,000 Da for DI and DIII, respectively. Moreover, DIII was identified as a glycoprotein with a pI of 3.8, and DI was identified as a non-glycoprotein with a pI of 5.3. When comparing the ratio of the CMC-saccharifying activity and CMC-liquefying activity, DI exhibited a steep slope, characteristic of an endoglucanase, whereas DIII exhibited a low slope, characteristic of an exoglucanase. The substrate specificity of the purified enzymes revealed that DI efficiently hydrolyzed CMC as well as xylan, whereas DIII exhibited a high activity on microcrystalline celluloses, such as Sigmacells. A comparison of the hydrolysis patterns for pNP-glucosides (DP 2-5) using an HPLC analysis demonstrated that the halosidic bond 3 from the nonreducing end was the preferential cleavage site for DI, whereas bond 2, from which the cellobiose unit is split off, was the preferential cleavage site for DIII. The partial N-terminal amino acid sequences for the purified enzymes were
-for DI and
-for DIII. The apparent sequences exhibited high sequence similarities with other bacterial
-1,4-glucanases as well as
Effectiveness of Various Pseudomonas spp. and Burkholderia caryophylli Containing ACC-Deaminase for Improving Growth and Yield of Wheat (Triticum aestivum L.)
Shaharoona, B. ; Jamro, G.M. ; Zahir, Z.A. ; Arshad, M. ; Memon, K.S. ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1300~1307
This study assessed the possible role of different traits in selected plant growth-promoting rhizobacteria (PGPR) for improving wheat growth and yield under natural conditions. Rhizobacteria exhibiting 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity were isolated and screened for their growth-promoting activity in wheat under axenic conditions. Five isolates belonging to Pseudomonas and one Burkholderia caryophylli isolate that showed promising performances under axenic conditions were selected and characterized for in vitro ACC-deaminase activity, chitinase activity, auxin production, P solubilization, and root colonization. These isolates were then used as inocula for wheat cultivated under natural conditions in pot and/or field trials. Significant increases in root elongation, root weight, tillers per pot, 1,000-grain weight, and grain and straw yields were observed in response to inoculation with PGPR in the pot trials. Inoculation with these PGPR was also effective under field conditions and increased the wheat growth and yield significantly. However, the efficacy of the strains was inconsistent under the axenic, pot, and field conditions. Pseudomonas fluorescens (
), which exhibited a relatively high in vitro ACC-deaminase activity, chitinase activity, auxin production, and P solubilization and more intensive root colonization, was the most efficient isolate under the field conditions. Therefore, these results demonstrated that ACC-deaminase activity is an efficient parameter for the selection of promising PGPR under axenic conditions. However, additional traits of PGPR, including auxin production, chitinase activity, P solubilization, and root colonization, are also important for selecting PGPR as biofertilizers.
In Vitro Evolution of Lipase B from Candida antarctica Using Surface Display in Hansenula polymorpha
Kim, So-Young ; Sohn, Jung-Hoon ; Pyun, Yu-Ryang ; Yang, In-Seok ; Kim, Kyung-Hyun ; Choi, Eui-Sung ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1308~1315
Lipase B from Candida antarctica (CalB) displayed on the cell surface of H. polymorpha has been functionally improved for catalytic activity by molecular evolution. CalB was displayed on the cell surface by fusing to a cell-wall anchor motif (CwpF). A library of CalB mutants was constructed by in vivo recombination in H. polymorpha. Several mutants with increased whole-cell CalB activity were acquired from screening seven thousand transformants. The two independent mutants CalB 10 and CalB 14 showed an approximately 5 times greater whole-cell activity than the wild-type. When these mutants were made as a soluble form, CalB 10 showed 6 times greater activity and CalB 14 showed an 11 times greater activity compared with the wild-type. Sequence analyses of mutant CALB genes revealed amino acid substitutions of
in CalB10 and
in CalB14. The substituted
in both mutants was located near the proline site of the
10 helix. This mutation was assumed to induce a conformational change in the
10 helix and increased the
value of mutant CalB approximately 6 times. Site-directed mutagenized CalB, LQ (
) was secreted into the culture supernatant at an amount of approximately 3 times more without an increase in the CalB transcript level, compared with the wild-type.
Development of a Protein Secretion System with the Application of Sec-dependent Protein Secretion Components
Kim, Sam-Woong ; Kim, Young-Hee ; Yoo, Ah-Young ; Yu, Jong-Earn ; Hur, Jin ; Lee, John-Hwa ; Cha, Jae-Ho ; Kang, Ho-Young ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1316~1323
In order to induce high levels of protein secretion, we have constructed a recombinant plasmid, designated pBP244, into which was incorporated key components of the type-II See-dependent secretion system, including LepB (signal peptidase), SecA (ATPase), and SecB (chaperone). The biological activities of the LepB, SecA, and SecB components expressed from genes harbored by pBP244 appeared to play their normal roles. In order to evaluate the protein secretion, a pspA (Streptococcus
) gene was cloned into pBP244, resulting in pBP438. S. typhimurium harboring pBP438 grown until the stationary phase, secreted a higher level of PspA into the culture supernatants than did the strain harboring pYA3494. The strain harboring pBP438 secreted a supernatant amount 1.71-fold, a periplasmic space amount 1.47-fold, and an outer membrane amount 1.49-fold higher than that of pYA3494. S. typhimurium
plasmid pBP244 and pBP438 for 60 generations in LB broth harboring DAP, thereby indicating that pBP244 and pBP438 were quite stable in the Salmonella strain.
Candicidal Action of Resveratrol Isolated from Grapes on Human Pathogenic Yeast C. albicans
Jung, Hyun-Jun ; Seu, Young-Bae ; Lee, Dong-Gun ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1324~1329
Resveratrol (3,5,4'-trihydroxystilbene) is a naturally occurring, multi-biofunctional chemical existing in grapes and various other plants as a polyphenol type, and it is one of the best known natural anticancer and antiatherosclerosis reagents. In this study, we investigated the antifungal action by resveratrol in Candida albicans, which is a human infectious fungi as an agent of candidiasis. Resveratrol displayed potent fungicidal activity in an energy-dependent manner, without any hemolytic effects against human erythrocytes. It was found that the serum-induced mycelial forms, which playa crucial role in the pathogenesis of C. albicans during host tissue invasion, were disrupted by resveratrol. To understand the correlation between lethal effects and resveratrol action, we examined the physiological changes of C. albicans. A significant accumulation of intracellular trehalose was induced by stress responses to resveratrol action, and a remarkable arrest of cell-cycle processes at the S-phase in C. albicans occured. Therefore, the fungicidal effects of resveratrol demonstrate that this compound is a potential candidate as an antifungal agent in treating infectious diseases by candidal infections.
Annotation and Expression Profile Analysis of cDNAs from the Antarctic Diatom Chaetoceros neogracile
Jung, Gyeong-Seo ; Lee, Choul-Gyun ; Kang, Sung-Ho ; Jin, Eon-Seon ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1330~1337
To better understand the gene expression of the cold-adapted polar diatom, we conducted a survey of the Chaetoceros neogracile transcriptome by cDNA sequencing and expression of interested cDNAs from the Antarctic diatom. A non-normalized cDNA library was constructed from the C. neogracile, and a total of 2,500 cDNAs were sequenced to generate 1,881 high-quality expressed sequence tags (ESTs) (accession numbers EL620615-EL622495). Based on their clustering, we identified 154 unique clusters comprising 342 ESTs. The remaining 1,540 ESTs did not cluster. The number of unique genes identified in the data set is thus estimated to be 1,694. Taking advantage of various tools and databases, putative functions were assigned to 939 (55.4%) of these genes. Of the remaining 540 (31.9%) unknown sequences, 215 (12.7%) appeared to be C. neogracile-specific since they lacked any significant sequence similarity to any sequence available in the public databases. C. neogracile consisted of a relatively high percentage of genes involved in metabolism, genetic information processing, cellular processes, defense or stress resistance, photosynthesis, structure, and signal transduction. From the ESTs, the expression of these putative C. neogracile genes was investigated: fucoxanthin chlorophyll (chl) a,c-binding protein (FCP), ascorbate peroxidase (ASP), and heat-shock protein 90 (HSP90). The abundance of ASP and HSP90 changed substantially in response to different culture conditions, indicating the possible regulation of these genes in C. neogracile.
Streptochlorin, a Marine Natural Product, Inhibits
Activation and Suppresses Angiogenesis In Vitro
Choi, In-Kwon ; Shin, Hee-Jae ; Lee, Hyi-Seung ; Kwon, Ho-Jeong ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1338~1343
Angiogenesis is an essential step in tumor progress and metastasis. Accordingly, small molecules that inhibit angiogenesis would appear to be a promising way to cure angiogenesis-related diseases, including cancer. In the present study, we report that streptochlorin, a small molecule from marine actinomycete, exhibits a potent antiangiogenic activity. The compound potently inhibited endothelial cell invasion and tube formation stimulated with vascular endothelial cell growth factor (VEGF) at low micromolar concentrations where it showed no cytotoxicity to the cells. In addition, streptochlorin inhibited TNF-
activation in the newly developed cell-based reporter gene assay. These data demonstrate that streptochlorin is a new inhibitor of
activation and can be a basis for the development of novel anti-angiogenic agents.
Identification of Pseudomonas aeruginosa Genes Crucial for Hydrogen Peroxide Resistance
Choi, Young-Seok ; Shin, Dong-Ho ; Chung, In-Young ; Kim, Seol-Hee ; Heo, Yun-Jeong ; Cho, You-Hee ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1344~1352
An opportunistic human pathogen, Pseudomonas aeruginosa, contains the major catalase KatA, which is required to cope with oxidative and osmotic stresses. As an attempt to uncover the
-dependent regulatory mechanism delineating katA gene expression, four prototrophic
-sensitive mutants were isolated from about 1,500 TnphoA mutant clones of P. aeruginosa strain PA14. Arbitrary PCR and direct cloning of the transposon insertion sites revealed that one insertion is located within the katA coding region and two are within the coding region of oxyR, which is responsible for transcriptional activation of several antioxidant enzyme genes in response to oxidative challenges. The fourth insertion was within PA3815 (IscR), which encodes a homolog of the Escherichia coli iron-sulfur assembly regulator, IscR. The levels of catalase and SOD activities were significantly reduced in the iscR mutant, but not in the oxyR mutant, during the normal planktonic culture conditions. These results suggest that both IscR and OxyR are required for the optimal resistance to
, which involves the expression of multiple antioxidant enzymes including KatA.
Expression Analysis of the csp-like Genes from Corynebacterium glutamicum Encoding Homologs of the Escherichia coli Major Cold-Shock Protein CspA
Kim, Wan-Soo ; Park, Soo-Dong ; Lee, Seok-Myung ; Kim, Youn-Hee ; Kim, Pil ; Lee, Heung-Shick ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1353~1360
Three csp-like genes were identified in the Corynebacterium glutamicum genome and designated cspA, cspB, and cspA2. The genes cspA and cspA2 encode proteins, comprising of 67 amino acid residues, respectively. They share 83% identity with each other. Identity of those proteins with Escherichia coli Csp proteins was near 50%. The cspB gene encodes a protein composed of 127 amino acids, which has 40% and 35% sequence identity with CspA and CspA2, respectively, especially at its N-terminal region. Analysis of the gene expression profiles was done using transcriptional cat fusion, which identified not only active expression of the three genes at the physiological growth temperature of
but also growth phase-dependent expression with the highest activity at late log phase. The promoters of cspA and cspA2 were more active than that of cspB. The expression of the two genes increased by 30% after a temperature downshift to
, and such stimulation was more evident in the late growth phase. In addition, the cspA gene appeared to show DNA-binding activity in vivo, and the activity increased at lower temperatures. Interestingly, the presence of cspA in multicopy hindered the growth of the host C. glutamicum cells at
, but not at
. Altogether, these data suggest that cspA, cspB, and cspA2 perform functions related to cold shock as well as normal cellular physiology. Moreover, CspA and its ortholog CspA2 may perform additional functions as a transcriptional regulator.
Plant Growth-Promoting Potential of Endophytic Bacteria Isolated from Roots of Coastal Sand Dune Plants
Shin, Dong-Sung ; Park, Myung-Soo ; Jung, Se-Ra ; Lee, Myoung-Sook ; Lee, Kang-Hyun ; Bae, Kyung-Sook ; Kim, Seung-Bum ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1361~1368
Endophytic bacteria associated with the roots of coastal sand dune plants were isolated, taxonomically characterized, and tested for their plant growth-promoting activities. Ninety-one endophytic bacterial isolates were collected and assigned to 17 different genera of 6 major bacterial phyla based on partial 16S rDNA sequence analyses. Gammaproteobacteria represented the majority of the isolates (65.9%), and members of Pseudomonas constituted 49.5% of the total isolates. When testing for antagonism towards plant pathogenic fungi, 25 strains were antagonistic towards Rhizoctonia solani, 57 strains were antagonistic towards Pythium ultimum, 53 strains were antagonistic towards Fusarium oxysporum, and 41 strains were antagonistic towards Botrytis cinerea. Seven strains were shown to produce indole acetic acid (IAA), 33 to produce siderophores, 23 to produce protease, 37 to produce pectinase, and 38 to produce chitinase. The broadest spectra of activities were observed among the Pseudomonas strains, indicating outstanding plant growth-promoting potential. The isolates from C. kobomugi and M. sibirica also exhibited good plant growth-promoting potential. The correlations among individual plant growth-promoting activities were examined using phi coefficients, and the resulting data indicated that the production of protease, pectinase, chitinase, and siderophores was highly related.
Exopolysaccharide Production and Mycelial Growth in an Air-Lift Bioreactor Using Fomitopsis pinicola
Choi, Du-Bok ; Maeng, Jeung-Moo ; Ding, Ji-Lu ; Cha, Wol-Suk ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1369~1378
For effective exopolysaccharide production and mycelial growth by a liquid culture of Fomitopsis pinicola in an air-lift bioreactor, the culture temperature, pH, carbon source, nitrogen source, and mineral source were initially investigated in a flask. The optimal temperature and pH for mycelial growth and exopolysaccharide production were
and 6.0, respectively. Among the various carbon sources tested, glucose was found to be the most suitable carbon source. In particular, the maximum mycelial growth and exopolysaccharide production were achieved in 4% glucose. The best nitrogen sources were yeast extract and malt extract. The optimal concentrations of yeast extract and malt extract were 0.5 and 0.1%, respectively.
were found to be the best mineral sources for mycelial growth and exopolysaccharide production. In order to investigate the effect of aeration on mycelial growth and exopolysaccharide production in an air-lift bioreactor, various aerations were tested for 8 days. The maximum mycelial growth and exopolysaccharide production were 7.9 g/l and 2.6 g/l, respectively, at 1.5 vvm of aeration. In addition, a batch culture in an air-lift bioreactor was carried out for 11 days under the optimal conditions. The maximum mycelial growth was 10.4 g/l, which was approximately 1.7-fold higher than that of basal medium. The exopolysaccharide production was increased with increased culture time. The maximum concentration of exopolysaccharide was 4.4 g/l, which was about 3.3-fold higher than that of basal medium. These results indicate that exopolysaccharide production increased in parallel with the growth of mycelium, and also show that product formation is associated with mycelial growth. The developed model in an air-lift bioreactor showed good agreement with experimental data and simulated results on mycelial growth and exopolysaccharide production in the culture of F. pinicola.
Sufflavibacter maritimus gen. nov., sp. nov., Novel Flavobacteriaceae Bacteria Isolated from Marine Environments
Kwon, Kae-Kyoung ; Yang, Seung-Jo ; Lee, Hee-Soon ; Cho, Jang-Cheon ; Kim, Sang-Jin ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1379~1384
Four Gram-negative, chemoheterotrophic, non-motile, yellow-colored strains were isolated from the East Sea or from deep-sea sediments of Nankai Trough by standard dilution plating. Characterization by polyphasic approaches indicated that the four strains are members of the same species. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the strains formed a coherent and novel genus-level lineage within the family Flavobacteriaceae. The dominant cellular fatty acids were i-C15:0, 3-OH i-C17:0, and 2-OH i-C15:0 and/or C16:1
. Predominance of 2-OH i-C15:0 and/or C16:1
$ clearly differentiated the strains from closely related members. The DNA G+C contents ranged 35.1-36.2 mol%. It is proposed, from the polyphasic evidence, that the strains should be placed into a novel genus and species named Sufflavibacter maritimus gen. nov., sp. nov., with strain
as the type strain.
Engineering and Characterization of the Isolated C-Terminal Domain of 5-Enolpyruvylshikimate-3-phosphate (EPSP) Synthase
Kim, Hak-Jun ; Kim, Hyun-Woo ; Kang, Sung-Ho ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1385~1389
5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase catalyzes the formation of EPSP and inorganic phosphate from shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) in the biosynthesis of aromatic amino acids. To delineate the domain-specific function, we successfully isolated the discontinuous C-terminal domain (residues 1-21, linkers, 240-427) of EPSP synthase (427 residues) by site-directed mutagenesis. The engineered C-terminal domains containing no linker (CTD), or with gly-gly (
) and gly-ser-ser-gly (
) linkers were purified and characterized as having distinct native-like secondary and tertiary structures. However, isothermal titration calorimetry (ITC),
revealed that neither its substrate nor inhibitor binds the isolated domain. The isolated domain maintained structural integrity, but did not function as the half of the full-length protein.
Analysis of the Stress Effects of Endocrine Disrupting Chemicals (EDCs) on Escherichia coli
Kim, Yeon-Seok ; Min, Ji-Ho ; Hong, Han-Na ; Park, Ji-Hyun ; Park, Kyeong-Seo ; Gu, Man-Bock ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1390~1393
In this study, three of the representative EDCs,
-estradiol, bisphenol A, and styrene, were employed to find their mode of toxic actions in E. coli. To accomplish this, four different stress response genes, recA, katG, fabA, and grpE genes, were used as a representative for DNA, oxidative, membrane, or protein damage, respectively. The expression levels of these four genes were quantified using a real-time RT-PCR after challenge with three different EDCs individually. Bisphenol A and styrene caused high-level expression of recA and katG genes, respectively, whereas
-estradiol made no significant changes in expression of any of those genes. These results lead to the classification of the mode of toxic actions of EDCs on E. coli.
Acaricidal Effects of Quinone and Its Congeners and Color Alteration of Dermatophagoides spp. with Quinone
Lee, Hoi-Seon ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1394~1398
Acaricidal activity of the active constituent derived from Pyrus ussuriensis fruits against Dermatophagoides farinae and D. pteronyssinus was examined and compared with that of the commercial benzyl benzoate. The
value of the ethyl acetate fraction obtained from the aqueous extract of P. ussuriensis fruits was 9.51 and
against D. farinae and D. pteronyssinus, respectively. The active constituent was identified as quinone by spectroscopic analyses. On the basis of
values with quinone and its congeners, the compound most toxic against D. farinae was quinone (
), followed by quinaldine (1.46), benzyl benzoate (9.32), 4-quinolinol (86.55), quinine (89.16), and 2-quinolinol (91.13). Against D. pteronyssinus, these were quinone (
), followed by quinaldine (1.29), benzyl benzoate (8.54), 4-quinolinol (78.63), quinine (82.33), and 2-quinolinol (86.24). These results indicate that the acaricidal activity of the aqueous extracts can be mostly attributed to quinone. Quinone was about 7.8 and 8.4 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus. Additionally, quinaldine was about 6.4 and 6.6 times more toxic than benzyl benzoate against D. farinae and D. pteronyssinus, respectively. Furthermore, the skin color of the dust mites was changed from colorless-transparent to dark brown-black by the treatment of quinone. These results indicate that quinone can be very useful as potential control agents, lead compounds, or the indicator of house dust mites.
The Virulence of Vibrio vulnificus is Affected by the Cellular Level of Superoxide Dismutase Activity
Kang, In-Hye ; Kim, Ju-Sim ; Lee, Jeong-K. ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1399~1402
The virulence of superoxide dismutase (SOD) mutants of Vibrio vulnificus, as tested by intraperitoneal injection into mice, decreases in the order of sodC mutant, sodA mutant, and sodB mutant lacking CuZnSOD, MnSOD, and FeSOD, respectively. The survival of SOD mutants under superoxide stress also decreases in the same order. The virulence of soxR mutant, which is unable to induce MnSOD in response to superoxide, is similar to that of the sodA mutant, as the survival of the soxR mutant under superoxide stress is similar to that of the sodA mutant. Consistently, the lowered survival of the soxR mutant is complemented not only with soxR but also with sodA. Thus, the virulence of V. vulnificus is significantly affected by the cellular level of SOD activity, and an increase in SOD level through MnSOD induction by SoxR under superoxide stress is essential for virulence.
Isolation and Structure Determination of Streptochlorin, an Antiproliferative Agent from a Marine-derived Streptomyces sp. 04DH110
Shin, Hee-Jae ; Jeong, Hyun-Sun ; Lee, Hyi-Seung ; Park, Song-Kyu ; Kim, Hwan-Mook ; Kwon, Ho-Jeong ;
Journal of Microbiology and Biotechnology, volume 17, issue 8, 2007, Pages 1403~1406
An antiproliferative agent, streptochlorin, was isolated from the fermentation broth of a marine actinomycete isolated from marine sediment. Phylogenetic analysis of the 16S rRNA gene sequence indicated that the strain belongs to the genus Streptomyces. Bioactivity guided fractionation of the culture extract by solvent partitioning, ODS open flash chromatography, and reversed-phase HPLC gave a pure compound, streptochlorin. Its structure was elucidated by extensive 2D NMR and mass spectral analyses. Streptochlorin exhibited significant antiproliferative activity against human cultured cell lines.