• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.764-769
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• 2000

The lipase gene(lip) from Bacillus stearothermophilus was recombined in vitro by utilizing the DNA shuffling technique. After four rounds of shuffling, transformation, and screening based on the initial rate of clear zone formation on a tricaprylin plate, a clone (M10) was isolated, the cell extract of which showed about 2.8-fold increased lipase activity. The DNA sequence of the mutant lipase gene (m10) showed 3 base changes, resulting in two cryptic mutations and one amino acid substitution: S113($AGC{\rightarrow}AGT$), L252 ($TTG{\rightarrow}TTA$), and G275E ($GGA{\rightarrow}GAA$). SDS-PAGE analysis revealed that the increased enzyme activity observed in M10 was partly caused by high expression of the m10 lipase gene. The amount of the expressed G275E lipase was estimated to comprise as much as 41% of the total soluble proteins of the cell. The maximum velocity ($V_{max}$) of the purified mutant enzyme for the hydrolysis of olive oil was measured to be 3,200 U/mg, which was 10% higher than that of the parental (WT) lipase (2,900 U/mg). Its optimum temperature for the hydrolysis of olive oil was $68^{\circ}C$ and it showed a typical $Ca^{2+}$-dependent thermostability, properties fo which were the same as those of the WT lipase. However, the mutant enzyme exhibited a high enantiospecificity towards (S)-naproxen compared with the WT lipase. In addition, it showed increased hydrolytic activity towards triolein, tricaprin, tricaprylin, and tricaproin.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.91-94
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• 2009

An unreported disease of garlic was observed in commercial fields in Jiangsu province, China. The symptoms started as water soaked lesions at the base of the leaves. Later, water-soaked areas developed on stems and spread to the internal tissues, followed by yellowing and necrosis along leaf edges and soft rot of the stems. The causal organism isolated from symptomatic plants was identified as Pseudomonas fluorescens based on its biochemical and physiological characteristics and confirmed by the cellular fatty acid composition and Biolog data as well as 168 rRNA gene sequence analysis. The bacterial isolates caused similar symptoms when inoculated onto garlic plants. In addition, leek and shallot were susceptible to the P. fluorescens pathogen. However, the P. fluorescens pathogen failed to cause any symptoms when it was inoculated onto 15 other plants. This is the first report of a bacterial disease of garlic caused by P. fluorescens in China.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.43-51
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• 1993

Mitochondrial DNA(mt DNA) of Mammalian is the circular one which the 16.5K base pairs and show the maternal inheritance. Evolutional speed of nucleotide sequence is very fast. So that polymorphic analysis of mt DNA provide the useful informations to investigate the genetic relations of interspecies. Authors trials were focussed to compare with the polymorphic differences of mitochondrial DNA between Jindo and Japanese mongrel dogs. DNA was extracted from bloods of 21 head of Jindo dogs and 20 head of Japanese dogs and isolated using 10 kinds of restriction endonucleases(Apa I, BamH I, Bgl II, EcoR I, EcoR V, Hinc II. Hind III, Pst I, Sty I, Xba I) and then separated by the agarose gel electrophoresis. After sourthern blotting hybridization was completed using the mtDNA of Japanese mongrel dogs as a probe. Autoradiography was used to compare the polymorphism of mtDNA both dogs. The results obtained were as follows; 1. mt DNA of Jindo dog showed polymorphism resulting cleavage with four kinds of restriction endonuclease, Apa I, EcoR V, Hinc II, Sty I. While in the Japanese mongrel dogs observed the polymorphism in the five kinds of restriction endonuclease supplemented with EcoR I. 2. Compared with both dogs the frequency differences of DNA polymorphism were recognized in the specific restriction endonuclease Apa I. Consequently in the restriction endonuclease Apa I both dogs classified with three types as A, B, C however in the Jindo dogs frequency of C type was 71.5 percent but in Japanese mongrel dogs observed 45 percent in the A type. 3. DNA polymorphism obtained from the use of five kinds of restriction endonuclease were classified with seven types. In Jindo dogs frequency was highest in the type 6 as 71.4 percent but in the Japanese mongrel dogs showed 35 percent in the type 5. 4. Genetic distances calculated by NEI method showed 0.0089 in Jindo dogs and was 0.0094 in the Japanese mongrel dogs.

• Journal of Microbiology
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• v.42 no.3
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• pp.188-193
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• 2004

Xanthobacter flavus strain UE15 was isolated in wastewater obtained from the Ulsan industrial complex, Korea. This strain functions as a 1,2-dichloroethane (1,2-DCA) degrader, via a mechanism of hydrolytic dechlorination, under aerobic conditions. The UE15 strain was also capable of dechlorinating other chloroaliphatics such as 2-chloroacetic acid and 2-chloropropionic acid. The dhlA gene encoding 1,2-DCA dechlorinase was cloned from the genomic DNA of the UE15 strain, and its nucleotide sequence was determined to consist of 933 base pairs. The deduced amino acid sequence of the DhlA dechlorinase exhibited 100％ homology with the corresponding enzyme from X. autotrophicus GJ10, but only 27 to 29％ homology with the corresponding enzymes from Rhodococcus rhodochrous, Pseudomonas pavonaceae, and Mycobacterium sp. strain GP1, which all dechlorinate haloalkane compounds. The UE15 strain has an ORF1 (1,356 bp) downstream from the dhlA gene. The OFR1 shows 99％ amino acid sequence homology with the transposase reported from X. autotrophicus GJ10. The transposase gene was not found in the vicinity of the dhlA in the GJ10 strain, but rather beside the dhlB gene coding for haloacid dechlorinase. The dhlA and dhlB genes were confirmed to be located at separate chromosomal loci in the Xanthobacter flavus UE15 strain as well as in X. autotrophicus GJ10. The dhlA and transposase the UE15 strain were found to be parenthesized by a pair of insertion sequences, 181247, which were also found on both sides of the transposase gene in the GJ10 strain. This unique structure of the dhlA gene organization in X. flavus strain UE15 suggested that the dechlorinase gene, dhlA, is transferred with the help of the transposase gene.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.186-191
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• 1994

The origin of the leading strand replication (ori) and of lagging strand replication (M-O) of R-plasmid pSBK203 was identified and its base sequence was determined. About 50 bp of ori sequence residues overlapped with the structural gene of rep. Sequence comparison reveals that pSBK-ori shares obvious identities with those of pT181 family and consists of two regions, one is conserved and the other is variable region. Of two palindrome sequence located one after another in upstream region of rep gene, palA' instead of palA which shares sequence homology with diverse family of plasmids such as pOX6, pC194, and pE194 seems to act as a signal for conversion of primarily replicated ssDNA to dsDNA (minus origin (M-O)).

• The Korean Journal of Mycology
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• v.18 no.2
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• pp.96-101
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• 1990

This study was conducted to select the promising antifungal microoganisms for biological control of wet bubble, Mycogone perniciosa. Ninty one isolates of fungi, 342 isolates of bacteria, and 556 actinomycetes were isolated from mushroom composts and soils, were subjected to primary screening test on agar medium base for their antimicrobial spectra. Among them, 12 bacteria and 71 actinomycetes were selected. Among the antibiotic producing microoganisms, 5 cultures were selected on the basis their antibiotic activities on casing soil with Benlate nontolerence M. perniciosa. Finally, AJ-117, AJ-136 and AK-139 were selected as microoganism with antifungal activity against two strains of M. perniciosa.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.45-49
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• 2004

Verticillium tenerum was detected from the samples of potato (Solanum tuberosum L.) and pumpkin (Cucurbita maxima Duch.) in Korea. The samples on which this species was detected were potato tubers collected from Pyungchang and Gimjae, and fruits and seeds of pumpkin from Yeonchon in 2003. The conidiophores of the fungus produced mainly three to five phialides in verticil. The phialides were narrow, flask-shaped, only very slightly swollen at the base, and taper subulately to a narrow neck. They were hyaline, $10{\sim}26{\times}2{\sim}5\;{\mu}m$. The conidia were formed in slimy heads, and were oval to ellipsoidal, pale reddish-brown, $2.5{\sim}7.5{\times}2{\sim}4\;{\mu}m$. The colony on the substrata was unique, showing brick-red color. This is the first report on the distribution of Verticillium tenerum in Korea.

• BMB Reports
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• v.38 no.1
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• pp.89-96
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• 2005

Earlier, we reported that the bacteriophage $\lambda$ P gene product is lethal to Escherichia coli, and the E. coli rpl mutants are resistant to this $\lambda$ P gene-mediated lethality. In this paper, we show that under the $\lambda$ P gene-mediated lethal condition, the host DNA synthesis is inhibited at the initiation step. The rpl8 mutation maps around the 83 min position in the E. coli chromosome and is 94% linked with the dnaA gene. The rpl8 mutant gene has been cloned in a plasmid. This plasmid clone can protect the wild-type E. coli from $\lambda$ P gene-mediated killing and complements E. coli dnaAts46 at $42^{\circ}C$. Also, starting with the wild-type dnaA gene in a plasmid, the rpl-like mutations have been isolated by in vitro mutagenesis. DNA sequencing data show that each of the rpl8, rpl12 and rpl14 mutations has changed a single base in the dnaA gene, which translates into the amino acid changes N313T, Y200N, and S246T respectively within the DnaA protein. These results have led us to conclude that the rpl mutations, which make E. coli resistant to $\lambda$ P gene-mediated host lethality, are located within the DNA initiator gene dnaA of the host.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.285-290
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• 2011

Fusarium graminearum virus 2 (FgV2) infects Fusarium graminearum strain 98-8-60 and has at least five segments of double-stranded RNAs (dsRNAs), denoted as dsRNA-1 to dsRNA-5. In this study, the genome of FgV2 was sequenced and its phylogenetic relationship with other mycoviruses was analyzed. The lengths of FgV2 dsRNAs 1-5 ranged from 2414 to 3580 base pairs (bp). The 5' and 3' untranslated regions (UTRs) are highly conserved, and each dsRNA segment had 78-105 and 84-306 bp of 5' and 3' UTRs, respectively. Each dsRNA segment contained a single open reading frame (ORF). Computer analysis of dsRNA-1 revealed a putative open reading frame (ORF) that shows high sequence identity with an RNA-dependent RNA polymerase (RdRp) containing eight conserved motifs. dsRNAs 2-5 also each contain one putative ORF coding for products of unknown function. The sequences of FgV2 dsRNA-2 and dsRNA-3 have significant sequence identity with Magnaporthe oryzae chrysovirus 1 (MoCV1) dsRNA-3 and -4, respectively. When compared to other dsRNA mycoviruses in a phylogenetic analysis of the putative RdRp protein, FgV2 was found to form a distinct virus clade with Aspergillus mycovirus 1816 and MoCV1 in the family Chrysoviridae.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.995-1000
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• 2010

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding a protein of 220 amino acids with a molecular mass of 24.5 kDa. The amino acid sequence was 79% identical to that of deoxyribose 5-phosphate aldolase (DERA) from Geobacillus sp. Y412MC10. The deoC gene encoding DERA was cloned into an expression vector and the protein was expressed in Escherichia coli. The recombinant DERA was purified using Ni-NTA affinity chromatography and then characterized. The optimum temperature and pH of the enzyme were $50^{\circ}C$ and 6.0, respectively. The specific activity for the substrate deoxyribose 5-phosphate (DR5P) was $62\;{\mu}mol/min/mg$. The $K_m$ value for DR5P was determined to be 145 mM with the $k_{cat}$ value of $3.2{\times}10^2/s$ from Lineweaver-Burk plots. The EA001 DERA showed stability toward a high concentration of acetaldehyde (100 mM).