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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Microbiology and Biotechnology Letters
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The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 32, Issue 4 - Dec 2004
Volume 32, Issue 3 - Sep 2004
Volume 32, Issue 2 - Jun 2004
Volume 32, Issue 1 - Mar 2004
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Characterization of the scr Gene Cluster Involved! in Sucrose Utilization in Bifidobacterium longum
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 199~205
The nucleotide sequence of 8.6-kb EcoRI fragment containing sucrose phosphorylase gene isolated from Bifidobacterium longum SJ32 was determined. It was found that the fragment contained five open reading frames including the gene cluster for sucrose utilization such as a sucrose phosphorylase (ScrP), a sucrose transporter (ScrT), and a GalR-LacI-type transcriptional regulator (ScrR) identified by amino acid homology. Each gene showed over 94% amino acid homology among various B. longum strains. Genomic organization of the gene cluster is the same as those of other strains of B. longum but different from that of B. lactis. In spite of high homology of each gene among B. longum strains, the difference of flanking sequences of the gene cluster between strains SJ32 and NCC2705 insinuates the horizontal transfer of scrPTR between B. longum strains. The increase of sucrose phosphorylase activity in heterologous E. coli system by the co-expression of scrT with scrP against the single expression of scrP was measured. It seems to be the result of sucrose uptake increment by scrT in the host and is an indirect evidence that scrT is the gene for sucrose transport. The existence of multiple sucrose uptake systems in B. longum is supposed from the findings of several genes besides scrPTR involved in sucrose uptake in the genome of B. longum NCC2705.
Secretion and Localization of Pseudomonas auratiaca Levansucrase Expressed in Saccharomyces cerevisiae
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 206~211
Levansucrase gene(lscA) from Pseudomonas aurantiaca was subcloned downstream of GAL1 promoter in pYES 2.0 and pYInu-AT [GAL10 promoter ＋ exoinulinase signal sequence of Kluyveromyces marxianus], resulting pYES-lscA and p YInu-lscA, respectively. The two expression plasmids were introduced into an invertase-deficient strain, Sacchromayces cerevisiae SEY2102, and transformants with high activity of levansucrase were selected. When each yeast transform ants was cultivated in medium containing galactose, the extracellular and intracellular activities of levansucrase reached about 8.62 U/ml with the strain harboring pYES-lscA and 5.43 U/ml with the strain harboring pYInu-lscA. The levansucrase activity of 80% was detected in the periplasmic space and cytoplasm. The levansucrase activity in the medium of SEY2102/pYInu-lscA was 0.87 U/ml whereas that of SEY2102/pYES-lscA was 0.47 U/ml, which implying the exoinulinase signal sequence didn't enhance the secretion efficiency of levansucrase. Furthermore, the recombinant levansucrase expressed in yeast seems to be produced as a hyper-glycosylated form.
High-Level Expression of A Bacillus subtilis Mannanase Gene in Escherichia coli.
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 212~217
The gene coding for mannanase from Bacillus subtilis WL-7, a number of glycosyl hydrolase family 26, was hyperexpressed in Escherichia coli. Two recombinant plasmids, pE7MAN and pENS7, were constructed by introducing the complete mannanase gene and the mature mannanase gene lacking N-terminal signal peptide region into a expression vector pET24a(＋), respectively. The level of mannanase produced by E. coli BL21 (DE3) carrying pENS7, which included the mature mannanase gene, was considerably higher than that by E. coli BL21 (DE3)/pE7MAN. Almost mannanase produced by the recombinant E. coli carrying pENS7 at growth temperature of
existed as inactive enzyme of insoluble form. Growth at temperature below
increased the soluble fraction of mannanase having catalytic activity in the recombinant E. coli cells. The highest productivity of active mannanase was observed in cell-free extract of the recombinant E. coli grown at growth temperature ranging from
, while mannanase activity per soluble protein of the cell-free extract was highest in the cells grown at
Isolation and Characterization of Bacteriolytic Wild Myxobacteria
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 218~223
Myxobacteria are Gram-negative soil bacteria known to be a rich source of potentially useful secondary metabolites. We have isolated 204 strains of bacteriolytic myxobacteria from soil samples collected in Korea and determined their 16S rRNA sequences. Sequence analysis of the partially determined 16S rRNA sequences has suggested that 132 isolates (65% of total isolates) belong to the genus Myxococcus and 59 isolates (29% of total isolates) belong to the genus Corallococcus. Meanwhile, 4 isolates appear to be Archangium spp. and the other 4 isolates appear to be Stigmatella spp. Genera of the remained 5 isolates have not been identified because their 16S rRNA sequences are distantly related to those of known myxobacteria.
The Isolation of Bacillus sphaericus 366M-9 Producing New Cephalosporin-C Deacetylase (CAH) and its Enzymatic Characterization
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 224~229
Several microorganisms (esterase-producing group) were isolated by the solid selective media containing-naphtylacetate. Among them, strain 366M-9 having a high activity of cephalosporin-C deacetylase (CAH; EC 126.96.36.199) was selected. The strain 366M-9 was identified as Bacillus sphaericus on the basis of morphological, physiological, and biochemical characteristics. The production of CAH reached at maximum value after 32 hrs, when cultivated in the optimal medium containing dextrin 2.5%, peptone 2.5%, sodium chloride 0.5%, dipotassium phosphate 0.25%, ferrous sulfate 0.02%, and 7-ACA 0.1% at
with initial pH 6.0. The CAH was purified by 3 steps with ammonium sulfate precipitation, adsorption chromatography on hydroxyapatite column, and Sephadex G-200 gel chromatography. The final enzyme preparation was homogeneous as judged by the analysis of SDS-PAGE and HPLC. Optimum temperature and pH for CAH activity were
and around 7.0, respectively. And the enzyme was stable at pH 6.0～8.0, up to
. The Michaelis-Menten constants (
were 0.87 mM and 1.22 unit/ml, respectively.
Characterization of Nitroreductase Purified from TNT-degrading Bacterium, Pseudomonas sp. HK-6.
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 230~237
In this study nitroreductase from Pseudomonas sp. HK-6 capable of degrading 2,4,6-trinitrotoluene (TNT) was characterized. Through a series of purification process including ammonium sulfate precipitation, DEAE-sepharose, and Q-sepharose, three different fractions I, II, and III having the enzyme activity of NTRs whose molecular weights were approximately 27 kDa were detected in fractions from HK-6 cells. Specific activity of the three fractions were approximately 4.85 unit/mg, 5.47 unit/mg, and 5.01 unit/mg, and concentrated to 9.0-, 10.1-, and 9.3-fold compared to crude extract, respectively. The optimal pH and temperature for the three NTR fractions were approximately 7.5 and
, respectively. Metal ions,
inhibited approximately 70% of enzymes activities of all NTR, while
did not stimulate or inhibit the activities. Monitoring the effect of chemicals on the enzyme activity revealed that those NTR fractions lost enzyme activity in presence of
-mercaptoethanol, but were a little influenced by dithiothreitol, EDTA and NaCl. The three NTR fractions demonstrated enzyme activities for nitrobenzene and RDX as well as TNT.
Isolation of Polyene Antifungal Antibiotics Against Gummy Stem Light Caused by Didymella bryoniae
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 238~242
Antifungal agents, flavofungin and fungichromin were isolated from the fermentation culture broth of a Streptomyces sp. SKM338. Biological evaluation of these antibiotics indicated that the compounds possesses broad spectrum antifungal activity against various pathogens. Especially, these compounds inhibited throughly growth of Didymella bryoniae, caused Gummy stem blight of melons, occurs in the southeastern Korea. Inhibition of this pathogen may be prevented from directly reducing both pre- and post-harvest yields.
Pilot Scale Production of (R)-3-Hydroxybutyric acid by Metabolically Engineered Escherichia coli.
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 243~248
Production of (R)-3-hydroxybutyric acid (R3HB) by fed-batch culture and continuous culture of metabolically engineered Escherichia coli harboring Ralstonia eutropha PHB biosynthesis and depolymerase genes was examined in a 30 1 pilot-scale fermentor. A new stable two-plasmid system, pBRRed containing the R. eutropha PHB depolymerase gene and pMCS 105 containing the R. eutropha PHB biosynthesis genes, was developed. Among a variety of E. coli strains harboring plasmids, recombinant E. coli XL-10 Gold (pBRRed, pMCS105) was able to produce R3HB with the highest efficiency in a batch culture. By the fed-batch culture of recombinant E. coli XL-10 Gold(pBRRed, pMCS 105) in a 30 1 fer-mentor, the final R3HB concentration was 22.4 g/l giving a productivity of 0.97 g/l-h. To produce R3HB to a high concentration with high productivity, a new strategy of fed-batch culture followed by a continuous culture was investigated. The maximum productivity and R3HB concentration were 5.06 g/l-h and 25.3 g/l, respectively. These results show that economical production of R3HB is possible by recombinant E. coli in large scale.
Changes in Acidity and Distributions of the Vancomycin-Resistant Lactic Acid Bacteria in the Kimchi Fermented at Different Temperatures
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 249~255
Chinese cabbage ('Baechu') Kimchi was fermented at the three different temperatures right after it was prepared. Samples were taken everyday for measuring bacterial populations, pH, and titratable acidity through the whole periods of fermentation up to 50 days. pH values and developed acidity were significantly affected by the fermenting temperatures of 4, 10, and
, suggesting that different bacterial flora has been established by the temperatures exposed. The modified MRS agar containing vancomycin (300
g/mL) was used for isolating the vancomycin-resistant LAB strains and 127 isolates were finally obtained. Of the LAB isolates, 13 isolates were subjected to the identification experiments based on the biochemical characteristics and the molecular-typing approach, an ITS-PCR, whether they belong to the genus Leuconostoc or not. The data obtained from API 50 CHL kit resulted that six isolates were identified as the members of Leuconostoc and six as Lactobacillus brevis strains except for a single isolate YKI 30-0401, which was not able to be identified because its biochemical traits were not matched to the database of API 50 CHL kit. It was noted that some isolates were distinct in a couple of some biochemical characteristics compared with those of the reference Leuconostoc species. To overcome the limitations experienced in the commercial identification products above, an ITS-PCR experiment was also conducted for the isolates, resulting that eight isolates belong to Leu. mesenteroides ssp. mesenteroides or dextranicum with a single band of 564 bp, and four to L. brevis strains. The ITS-PCR profiles clearly differentiated the closely-related LAB isolates for which same results were obtained by the biochemical method. This molecular approach, however, failed to produce the amplicons for the YKI 20-1003, leaving the strain unidentified. Judging from the identification data obtained in the Kimchi fermented at
, Leuconostoc spp. including Leu. mesenteroides/dextranicum were likely predominant species in the earlier stage and L. brevis occurred at the high level through the whole period. By contrast, L. brevis, as one of the major flora, possibly lead the fermentation from the beginning in the Kimchi fermented at
PCR-Based Sensitive Detection and Identification of Xanthomonas oryzae pv. oryzae
Lee, Byoung-Moo ; Park, Young-Jin ; Park, Dong-Suk ; Kim, Jeong-Gu ; Kang, Hee-Wan ; Noh, Tae-Hwan ; Lee, Gil-Bok ; Ahn, Joung-Kuk ;
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 256~264
A new primer set was developed for the detection and identification of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight (BLB) pathogen in rice plant. The nucleotide sequence of hpaA gene was determined from X. o. pv. oryzae str. KACC10331, and the sequence information was used to design primers for the application of the polymerase chain reaction (PCR). The nucleotide sequence of hpaA from X. o. pv. oryzae str. KACC 10331 was aligned with those of X. campestris pv. vesicatoria, X. campestris pv. campestris, X. axonopodis pv. citri, and X. axonopodis pv. glycines. Based on these results, a primer set(XOF and XOR) was designed for the specific detection of hpaA in X. o. pv. oryzae. The length of PCR products amplified using the primer set was 534-bp. The PCR product was detected from only X. o. pv. oryzae among other Xanthomonas strains and reference bacteria. This product was used to confirm the conservation of hpaA among Xanthomonas strains by Southern-blotting. Furthermore, PCR amplification with XOF and XOR was used to detect the pathogen in an artificially infected leaf. The sensitivity of PCR detection in the pure culture suspension was also determined. This PCR-based detection methods will be a useful method for the detection and identification of X. o. pv. oryzae as well as disease forecasting.
Removal of Malodorous Gases Emitted from a Wastewater Pumping Stations by Biological Methods
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 265~270
To select a promising technologies for removal of odorous gases emitted from a wastewater pump station, four methods such as activated carbon (A/C) adsorption, chemical absorption (acid and alkali scrubber), and two biofilters (polyurethane (PU) and worm cast) were investigated. The average odor removal efficiencies in the PU biofilter and A/C column was over 98%, but in a worm cast biofilter and chemical absorption were below 60-80%. The removal efficiency of PU biofilter was very stable (about 98-99%) in the range of retention times of 4-36s, and a maximum elimination capacity was $1.6
Deodorization costs for an activated carbon adsorption and a biofiltration method were investigated. With increasing odor intensity, the operating cost of the A/C column increased linearly, but the operating cost of the biofilteration increased slightly. The capital cost in a biofilter is about two times higher than that in an A/C column, but the operating cost is very lower than that of in A/C column. In conclusion, the biofiltration was evaluated one of the most promising technologies to control odor in a wastewater pump station.
Protective Effects of
-Immunan Isolated from the Mycelium of Ganoderma lucidum IY009 against Cisplatin-induced Nephrotoxicity
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 271~276
-Immunan was proteoglycan obtained from mycelium of Ganoderma lucidum IY009. In this study, the protective effects of
-Immunan, against the CDDP induced in vitro cytotoxicity and in vivo renal toxicity, was measured. Concentration dependent cytotoxicities of CDDP in normal kidney cells (Vero, TCMK-l) were reduced by
-Immunan treatment. Increased renal toxicity factors, such as elevation of blood urea nitrogen (BUN) and serum creatinine, reduction of kidney weight and malonidialdehyde (MDA), by intraperitoneal administration of CDDP in rats was improved. These results indicated that
-Immunan have a protective effects against the CDDP induced renal toxicity, however, it needed to confirm the detailed mechanism for therapeutic effects.
Antimicrobial Effect of Fraxinus rhynchophylla Extracts on Food-Borne Pathogens
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 277~281
This study was performed to investigate the antimicrobial effect of the Fraxinus rhynchophylla extracts against food-borne pathogens. First, the Fraxinus rhynchophylla was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Fraxinus rhynchophylla was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Fraxinus rhynchophylla extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Fraxinus rhynchophylla showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Fraxinus rhynchophylla and Portulaca aleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Fraxinus rhynchophylla against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Fraxinus rhynchophylla showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Fraxinus rhynchophylla retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Fraxinus rhynchophylla has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.
Isolation of Cryptic Polyene Hydroxylase Gene in Rare Actinomycetes via Polyene-specific Degenerate PCR.
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 282~285
The polyene antibiotics including nystatin, pimaricin, amphotericin and candicidin are a family of most promising antifungal polyketide compounds, typically produced by rare actinomycetes species. The biosynthetic gene clusters for these polyenes have been previously investigated, revealing the presence of highly homologous biosynthetic genes among polyene-producers such as polyketide synthase (PKS) and cytochrome P450 hydroxylase (CYP) genes. Based on amino acid sequence alignment among actinomycetes CYP genes, the highly-conserved regions specific for only polyene CYP genes were identified and chosen for degenerate PCR primers, followed by the PCR-screening with various actinomycetes genomic DNAs. Among tested several polyene non-producing actinomycetes strains, Pseudonorcardia autotrophica strain was selected based on the presence of PCR product with polyene-specific CYP gene primers, and then confirmed to contain a cryptic novel polyene hydroxylase gene in the chromosome. These results suggest that the polyene-specific hydroxylase gene PCR should be an efficient way of screening and isolating potentially-valuable cryptic polyene antibiotic biosynthetic genes from various microorganisms including rare actinomycetes.
Transglycosylation of Phenolic Compounds by the Recombinant Sucrose Phosphorylase Cloned from Bifidobacterium longum
Microbiology and Biotechnology Letters, volume 32, issue 3, 2004, Pages 286~289
Transglycosylation from sucrose to phenolic compounds by the recombinant sucrose phosphorylase from Bifidobacterium longum was studied. HPLC analysis revealed that the enzyme transferred glucosyl residue of sucrose to 1,2-dihydroxybenzene, 1,4-dihydroxybenzene, 1,2,3-trihydroxybenzene, and 2-hydroxybenzyl alcohol. The enzyme could transfer the glucosyl moiety of sucrose to phenolic compounds which have phenolic OH or alcoholic (hydroxymethyl) OH group.