• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.21-24
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• 1991

The promoter isolated from an alkali-tolerant Hwillus sp. chromosomal DNA was subcluned. The activity of promoter in B, subtilis and alkali-tolerant Bacillus sp. began to increase at the early stage. of spore formation. In the presence of 1% glucose, the promotcr activity repressed and was recovered by ;tddition of c-GMP in the medium.

• Microbiology and Biotechnology Letters
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• v.21 no.3
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• pp.239-246
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• 1993

Producing an extracellular alkaline lipase, this isolate JM123 was identified as a Pseudomonas aeruginosa strain from the results of the analyses of its morphological, biochemical and physiological properties. This strain showed the highest productivity of alkaline lipase when grown at pH 9.0 and 30C for 13-20 hours in the medium of 2% starch, 1% soytone, 0.5% peptone and 1% MgSO4.7H2O. However, this enzyme was greatly repressed when grown in the glucose containing medium. The culture broth was fractionated by the order of the ammonium sulfate precipitation, Sephadex G-200 gel filtration, DEAE-cellulose column chromatography, and Sephadex G-150 gel filtration.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.119-127
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• 1985

A series of Escherichia coli mutants were exmined for ability to convert glucose and ammonium salts into phenylalanine. This enabled the biochemical changes having major. effects on phenylaianine yield, and interactions between mutations, to be identified. Changes to the common pathway of aromatic biosynthesis having a major effects include desensitization of the first enzyme (3-deoxy-D-arabinoheptulosonate synthase) to end-product inhibition, and removal of repression of enzyme synthesis. It is suggested that the 3-deoxy-D-arabino-heptulosonate synthase Phe isoenzyme has a more important effect on yield. Similarly, removal of repression and end-product inhibition on the phenylalanine terminal pathway increased yield, and changes to both common and branch pathways were synergistic. Blockage of the typrosine and tryptophan pathways had minor effects on phenylalanine yield, and a mutation affecting aramatic amino acid transport (aroP) decreased yield. With multiple-mutation strains hish specific rates of product formation (ie 0.1-0.17g phenylalanine/g cells/h) were obtained.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.407-411
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• 2007

Regulation of ${\beta}-xylosidase$ synthesis in Paenibacillus sp. DC-22 was studied to optimize the enzyme production. ${\beta}-Xylosidase$ synthesis of the Paenibacillus sp. DG-22 was observed to be regulated by carbon sources present in culture media. The synthesis of ${\beta}-xylosidase$ was induced by xylan and methyl ${\beta}-D-xylopyranoside$ (${\beta}MeXyl$) but slightly repressed by readily metabolizable monosaccharides. ${\beta}MeXyl$ was found to be the best substrate for the induction of ${\beta}$-xylosidase and the most effective induction was obtained at a concentration of 10 mg/ml. ${\beta}-Xylosidase$ production showed a cell growth associated profile with the maximum amount formed during the late exponential phase of growth. The presence of glucose and xylose decreased the level of ${\beta}-xylosidase$ activity indicating that its production was subjected to a form of carbon catabolite repression. SDS-PAGE and zymogram techniques demonstrated the induction by ${\beta}MeXyl$ and revealed the presence of one ${\beta}-xylosidase$ of approximately 80 kDa.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.800-808
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• 2005

Leuconostoc mesenteroides SY1, an isolate from kimchi, was able to ferment $\alpha$-galactosides, such as melibiose and raffinose. $\alpha$-Galactosidase ($\alpha$-Gal) activity was higher in cells grown on melibiose and raffinose than cells grown on galactose, sucrose, and fructose. $\alpha$-Gal activity was not detected in cells grown on glucose, indicating the operation of carbon catabolite repression (CCR). A 6 kb DNA fragment was PCR amplified using a primer set based on the nucleotide sequence of a putative $\alpha$-galactosidase gene (aga) from L. mesenteroides ATCC 8293. Nucleotide sequencing of the 6 kb fragment confirmed the presence of aga and other genes involved in the galactosides utilization, and the gene order was galR (transcriptional regulator)-aga-gaIK (galactokinase)-gaIT (galactose-1-phosphate uridylyltransferase). Northern blotting experiment showed that aga, gaIK, and gaIT constituted the same operon, that the transcription was induced by galactosides, such as melibiose and raffinose, whereas gaIR was independently transcribed as a monocistronic gene, and that the level of transcription was fairly constant. The aga was overexpressed in E. coli BL21 (DE3) using pET26b(+) vector, and $\alpha$-Gal was accumulated in E. coli as an inclusion body.

• Journal of Microbiology
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• v.45 no.4
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• pp.311-317
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• 2007

In this study, the effects of phosphate concentration and carbon source on the patterns of alkaline phosphatase (APase) and phospholipase (PLase) expression in Vibrio vulnificus ATCC 29307 were assessed under various conditions. The activities of these enzymes were repressed by excess phosphate (4 mM) in the culture medium, but this repression was reversed upon the onset of phosphate starvation in low phosphate defined medium (LPDM) containing 0.2 mM of phosphate at approximately the end of the exponential growth phase. The expressions of the two enzymes were also influenced by different carbon sources, including glucose, fructose, maltose, glycerol, and sodium acetate at different levels. The APase activity was derepressed most profoundly in LPDM containing fructose as a sole carbon source. However, the repression/derepression of the enzyme by phosphate was not observed in media containing glycerol or sodium acetate. In LPDM-glycerol or sodium acetate, the growth rate was quite low. The highest levels of PLase activity were detected in LPDM-sodium acetate, followed by LPDM-fructose. PLase was not fully repressed by high phosphate concentrations when sodium acetate was utilized as the sole carbon source. These results showed that multiple regulatory systems, including the phosphate regulon, may perform a function in the expression of both or either APase and PLC, in the broader context of the survival of V. vulnificus.

• Microbiology and Biotechnology Letters
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• v.8 no.3
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• pp.173-180
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• 1980

A source of D-xylose was required for the enhanced production of D-glucose isomerase of Streptomyces sp. strain K-17. D-glucose supported the luxuriant growth of the organism as well as D-xylose, but D-glucose isomerase activity was hardly detected in the D-glucose-grown cells. When the D-glucose-grown cells were incubated aerobically for a few hours in 0.5% xylose solution in 0.05 M phosphate buffer, pH 7.0, it was found that inductive formation of D-glucose isomerase occurred in the cells without multiplication. In the non-growth phase of cells the inductive formation of D-glucose isomerase occurred because a source of nitrogen for the synthesis of enzymes was obtained from turnover of protein accumulated in cells. D-ribose, L-arabinose, D-glucose, D-mannose, citrate, succinate and tartrate could not induce the formation of D-glucose isomerase, but D-xylose could induce. Inductinn of D-glucose isomerase was repressed by D-glucose and its catabolites : glycerol, succinate and citrate. Inductive formation of the enzymes in the non-growth phase was stimulated by $Ba^{2+}$, $Mg^{2+}$ and $Co^{2+}$, and inhibited by C $u^{2+}$, C $d^{2+}$, A $g^{+}$and H $g^{2+}$. The synthesis of enzymes in the induction system composed of 0.5% xylose solution was disrupted by actinomycin D, streptomycin, chloramphenicol, kanamycin, tetracycline, p-chloromercuribenzo ate, arsenate and 2, 4-dinitrophenol, but not disrupted by mitomycin C and penicillin G.icillin G.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.417-421
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• 1992

The expression pattern of the cloned SUC2 gene in recombinant Saccharomyces cerevisiae was investigated in a two-stage culture. The recombinant yeast grown in a glucose medium where the SUC2 gene was repressed was harvested and then resuspended in a sucrose medium to induce invertase expression. The maximum activity of 10 units was obtained in a medium containing 2 $g/\ell$ sucrose as a carbon source at $30^{\circ}C$ . The oscillatory behavior of invertase activity in response to glucose concentrations in the second stage was observed. This effect can be attributed to a series of events: invertase expression from the SUC2 gene. sucrose hydrolysis to glucose and fructose by invertase, SUC2 repression by high glucose concentration, invertase induction as a result of depletion of glucose used for the yeast growth. The invertase activity was increased by 72.5% when growth temperature changed from $30^{\circ}C$: to $35^{\circ}C$.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.159-168
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• 1998

Effect of plant growth regulators and end-product on the enzyme activities in cotyledons of Vigna angularis during germination was investigated by measuring the changes of $\alpha-amylase$ activities in attached and detached cotyledons applied growth regulators and sugars. The higher levels of $\alpha-amylase$ in detached cotyledons than those in cotyledons attached to the embryonic axis were due to both faster synthesis and slower degradation of the enzyme in the detached cotyledons than in the attached cotyledons. Levels of $\alpha-amylase$ activity were reduced by high concentrations of glucose and sucrose, and it is suggested that this effect was caused mostly by osmotic stress and partly by end-product repression. In detached cotyledons exogenously supplied $GA_3,$ IAA, kinetin, or their combinations has a small promotive effect on the developmental patterns of $\alpha-amylase$ activity ABA and uniconazole both prevented the synthesis of $\alpha-amylase$. Glucose inhibition of enzyme activity was partly reversed by the application of $GA_3,$ and CAMP. $GA_3,$ and cAMP seemed to act through a similar mechanism. The addition of inhibitors of protein and RNA synthesis largely prevented the increase of enzyme activity in the presence or absence of exogenous $GA_3,$. The pretreatment experiments with canavanine indicated that the earlier the time of addition was, the lower the amylase activity was.

• The Journal of Natural Sciences
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• v.17 no.1
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• pp.103-111
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• 2006

Regulation of invertase biosynthesis was studied with the E. coil harboring recombinant plasmid, pYC17. Biosynthesis of invertase in the recombinant E. coil was effectively induced in the presence of 30mM of sucrose for 3h. Glucose also repressed the invertase induction in the recombinant E. coil at 10 mM, lower than that of parent strain (30 mM).