• Journal of Life Science
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• v.20 no.2
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• pp.292-297
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• 2010

Anthocyanin, a phenolic compound, is a pigment that shows blue or red color in the fruit, petal and other tissues. It is an important factor in grape berry skin pigment and accumulates only in the skin. This skin-specific accumulation of anthocyanin has been reported to be regulated by the ufgt gene which encodes UDP-glucose: flavonoid 3-O-glucosyltransferase that participates in the biosynthesis of anthocyanin. The ufgt gene is expressed only in berry skin, while the other genes involved in the biosynthetic pathway are expressed in both skin and flesh tissues. In order to determine whether anthocyanin accumulation is primarily regulated by compartment of UFGT, a ufgt cDNA clone was isolated from grape berry, its open reading frame was ligated in pBI121 vector in either a sense or an antisense orientation under the control of the CaMV35S promoter and the recombinant constructs were incorporated into tobacco plants. Several transgenic lines were selected and characterized to determine the level of expression of the grapevine ufgt transcript and endogenous homologs of tobacco. Compared to the wild-type, the amount of anthocyanins in sense transgenic plants increased by 44%, while the amount of anthocyanins in antisense transgenic plants decreased by 88%. In addition, the color of flowers became intense in the sense transgenic plants. These results suggest that over-expression or repression of the ufgt gene affected the accumulation of anthocyanin in flowers of tobacco.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.349-354
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• 2000

Abstract A facultative alkalophilic gram-negative Vibrio metschnikovii strain RH530, isolated from the wastewater, produced several alkaline proteases (VAP) including six alkaline serine proteases and a metalloprotease. From this strain, high yielding YAP mutants were isolated by NTG treatment. The isolated mutant KS1 showed nine times more activity than the wild-type after optimization of the culture media. The production was regulated by catabolite repression when glucose was added to the medium. The effects of several organic nitrogen sources on the production of the YAP were investigated to avoid catabolite repression. The combination of 4% wheat gluten meal (WGM), 1.5% cotton seed flour (eSF), and 5% soybean meal (SBM) resulted in the best production when supplemented with 1% NaCl. The YAP showed a resistance to surfactants such as $sodium-{\alpha}-olefin$ sulfonate (AOS), polyoxy ethylene oxide (POE), and sodium dodecyl sulfate (SDS), yet not to linear alkylbenzene sulfonate (LAS). However, the activity of the YAP was restored completely when incubated with LAS in the presence of POE or $Na_2SO_4$. The YAP was stable in a liquid laundry detergent containing 6.6% SLES (sodium lauryl ether sulfate), 6.6% LAS, 19.8% POE, and stabilizing agents for more than two weeks at $40^{\circ}C$, but the stability was sharply decreased even after 1 day when incubated at $60^{\circ}C$. A washing performance test with the YAP exhibited it to be a good washing power by showing 51 % and 60% activity at $25^{\circ}C{\;}and{\;}40^{\circ}C$, respectively, thereby indicating that the YAP also has a good detergency at a low temperature. All the results suggest that the YAP produced from the mutant strain KSI has suitable properties for use in laundry detergents.rgents.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.749-755
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• 2005

The ccpA gene encoding catabolite control protein A (CcpA) of Leuconostoc mesenteroides SYl, a strain isolated from kimchi, was cloned, sequenced, analyzed for transcript, and overexpressed in Escherichia coli. The ccpA ORF (open reading frame) is 1,011 bp in size, which can encode a protein of 336 amino acid residues with a molecular mass of 36,739 Da. The transcription start site was mapped at a position 49 nucleotides upstream of the start codon, and promoter sequences were also identified. The putative cre site overlapped with the -35 promoter sequence. The deduced amino acid sequence of the CcpA contained the helix-turn-helix motif found in many DNA-binding regulatory proteins. CcpA from 1. mesenteroides SY1 had $54.6\%$ identity with CcpA from Lactobacillus casei. The Northern blot experiment showed that ccpA was transcribed as a single 1.1 kb transcript, and transcription was repressed when grown on media containing glucose. CcpA was overproduced in E. coli BL21(DE3) cells using the pET expression vector, and purified to an apparent homogeneity. Gel Mobility Shift Assay with purified CcpA and a DNA fragment containing the ere sequence of the $\alpha$-galactosidase gene (aga) from L. mesenteroides SY1 revealed that CcpA bound specifically to the cre site of aga.

• Journal of Microbiology and Biotechnology
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• v.3 no.3
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• pp.146-155
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• 1993

A DNA fragment from an alkali-tolerent Bacillus sp., conferring strong promoter activity, was subcloned into the promoter probe plasmid pPL703 and the nucleotide sequence of this promoter region was determined. The sequence analysis suggested that this highly efficient promoter region containing the complex clustered promoters comprised three kinds of promoters (P1, P2 and P3), which are transcribed by $\sigma^B (formerly \sigma^{37}), \sigma^E(formerly \sigma^{29}) and \sigma^A (formerly \sigma^{43})$ RNA polymerase holoenzymes which play major rules at the onset of endospore formation, during sporulation and at the vegetative phase of growth, respectively. S1 nuclease mapping experiments showed that all three promoters had staggered transcription initiation points. The results of chloramphenicol acetyltransferase assay after the subcloning experiments also indicated that the expression of these clustered promoters was correlated with the programs of growth and endospore development. Promoter P1, P2 and P3 were preceded by 75% AT, 79% AT and 81% AT regions, respectively, and a partial deletion of AT-rich region prevented transcription from promoter P1 in vivo. Two sets of 5 -AGTGTT-3 sequences and inverted repeat sequences located around the promoter P1 were speculated as the possible cis acting sites for the catabolite repression in B. subtilis. In vivo transcripts from these sequence regions may be able to form a secondary structure, however, the possibility that a regulatory protein induced by the excess amount of glucose could be bound to such a domain for crucial action remains to be determined.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.415-424
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• 2010

The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:87. A nonpolar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the ${\Delta}luxS$ mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxisrelated genes (flhD; fliA, C, D, S, Z; and cheA, Y, Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.243-249
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• 2017

An agar-degrading bacterium, designated as the GNUM08123 strain, was isolated from samples of red algae collected from the Yongil Bay near East Sea, Korea. The isolated GNUM08123 strain was gram-negative, aerobic, motile, and beige-pigmented, with $C_{16:0}$ (25.9%) and summed feature 3 (comprising $C_{16:1}{\omega}7c/iso-C_{15:0}2-OH$, 34.4%) as its major cellular fatty acids. A similarity search based on the 16S rRNA gene sequence revealed that it belonged to class Gammaproteobacteria and shared 97.7% similarity with the type strain Vibrio chagasii $R-3712^T$. The DNA G+C content of strain $GNUM08123^T$ was 46.9 mol%. The major isoprenoid quinone was ubiquinone-8. The results of DNA-DNA relatedness and 16S rRNA sequence similarity analyses, in addition to its phenotypic and chemotaxonomic characteristics, suggest that strain GNUM08123 is a novel species within genus Vibrio, designated as Vibrio sp. GNUM08123. Agarase production by strain GNUM08123 was induced by agar and sucrose, but was repressed probably owing to carbon catabolite repression by glucose and maltose.

• KSBB Journal
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• v.8 no.2
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• pp.133-142
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• 1993

The effects of genetic and environmental factors on productivity of a cloned protein were studied in recombinant Saccharomyces cerevisiae. Plasmid stability and copy level were very high for a $REP^+$ system(at ca. 10 generations, stability: 65-90%, plasmid copy number per cell: 40-200), whereas these were very low for a yep- system(at ca. 10 generations, stability: 30%, plasmid copy number per cell 20). In plasmids containing the $2{\mu}m$ circle genome, a $[cir^o]$ strain was a preferred host cell since the plasmid stability and the copy number in a $[cir^o]$ strain were higher than in a $[cir^+]$strain. Cloned gene expression was dependent on plasmid copy number and stability. The inducer (galactose) level played a very important role in cloned lacZ gene expression, showing that a galactose concentration of 0.8% was sufficient for induction of gene expression. Induction rate was very fast in the case of plasmids exhibiting high stability and copy number by a factor of 4 to 25. The time to reach the peak value of gene expression was longer when galactose was added at the start of fermentation (ca. 26 hours) than at the mid-exponential phase (ca. 6 hours). Glucose repression was reduced by a factor of 2 to 5 as the relative inducer level increased.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.637-645
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• 1999

Two putative regulator genes, mocR and mocS, of the moc (mannityl opine catabolism) operons in pTi15955 of the octopine-/mannityl opine-type Agrobacterium tumefaciens strain 15955, were tested for their possible roles as repressors in the moc operons. The regions upstream of macC and mocD, the first structural genes in the two divergently oriented moc operons, were transcriptionally fused into the promoterless lacZ reporter gene. Each of the lacZ-fusions was introduced into Agrobacterium strain UIA5, a Ti plasmid-cured derivative, harboring either a mocR or a mocS clone. The resulting strains were grown in media containing various sugar sources, and the $\beta$-galactosidase activities were quantitatively measured. The results suggested that MocR repressed the expression of macC and macD. The expression of the fused $\beta$-galactosidase was not induced by mannopine (MOP) or possible catabolic intermediates of the opine, e.g. santhopine (SOP), glucose, mannose, or glutamine. However, the repression was significantly relieved by the supplementation of MOP and the concomitant introduction of the agcA gene encoding MOP cyclase that catalyzes the lactonization of MOP to agropine (AGR). These results suggested that AGR, rather than MOP or the other catabolic intermediates, is the inducer for the expression of the operon. On the contrary to previous report showing that the induction levels of macC and macD were lowered by the supplementation of inorganic nitrogen in media, the expression of these genes was not affected by the level of nitrogen in our reporter system. MocS did not strongly repress the expressions of macC and mocD. It is possible that MocS may be involved in the regulation of the operons present downstream of the moc operon, which are responsible for the utilization of mannopinic acid and agropinic acid.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.8-16
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• 2013

An agar-hydrolyzing marine bacterium, strain GNUM08120, was isolated from Sargassum fulvellum collected from Yeongil bay of East Sea of Korea. The isolate was Gram-negative, aerobic, motile with single polar flagellum, and grew at 1-10% NaCl, pH 5.0-8.0, and $15-37^{\circ}C$. G+C content and the predominant respiratory quinone were 46.13 mol% and Q-8, respectively. The major cellular fatty acids were Summed feature 3 (24.5%), $C_{16:0}$ (21.7%), and $C_{18:1}{\omega}7c$ (12.5%). Based on 16S rRNA gene sequence similarity and DNA-DNA hybridization analyses, strain GNUM08120 was identified as a novel subspecies of Alteromonas macleodii, designated Alteromonas macleodii subsp. GNUM08120. Production of agarase by strain GNUM08120 was likely repressed by the effect of carbon catabolite repression caused by glucose. The crude agarase prepared from 12-h culture broth of strain GNUM08120 exhibited an optimum pH and temperature for agarase activity at 7.0 and $40^{\circ}C$, respectively. The crude enzyme produced (neo)agarobiose, (neo)agarotetraose, and (neo)agarohexaose as the hydrolyzed product of agarose.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.206-213
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• 1996

Talaromyces luteus 2004, a thermophilic mutant of T. luteus 6112 was obtained by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. T. luteus 2004 produced thermophilic carboxymethylcellulase (CMCase), and other polysaccharide enzymes: avicellase, xylanase, and ${\beta}-glucosidase$. Induction of CMCase production was shown at the highest level in 3% carboxymethylcellulose (CMC) minimal broth, indicating that CMC could work as an inducer. However, glucose and D-cellobiose showed catabolite repression for CMCase production which was under the control of CMC utilization. Optimal conditions for CMCase activity were at $70^{\circ}C$ and pH 4.0, suggesting that CMCase of T. luteus 2004 was a thermophilic enzyme.