• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.119-125
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• 1988

$\beta$-Glucosidase of Cellulomonas sp. CS1-1 in cellular compartment was localized with cell-bound form while Avicelase and carboxymethylcellulase (CMCase) were appeared with extracellular enzyme. Cell growth on cellulose or CMC minimal broth was increased by glucose addition. $\beta$-Glucosidase production on cellobiose or CMC minimal broth was repressed by the addition of glucose. However, on CMC minimal broth, the enzyme production was specially stimulated by cellobiose addition. $\beta$-Glucosidase production was also induced by CMC, starcth and maltose compared with glycerol, arabinose, xylose and trehalose. From the above results, it was concluded that glucose effect on $\beta$-glucosidase biosynthesis showed catabolite repression, but enzyme production was induced by cellobiose, CMC, and starch, indicating that $\beta$-glucosidase is inducible enzyme. Yeast extract stimulated $\beta$-glucosidase production more than peptone and ammonium sulfate. $\beta$-Glucosidase activity was increased with 50mM MgCl$_2$in 10mM potassium phosphate buffer (pH 7.0). Optimum conditions for enzyme activities were pH 6.0 and 42$^{\circ}C$, Km value of $\beta$-glucosidase for p-nitrophenyl-$\beta$-D-glucosidase was 0.256mM and Ki for $\beta$-D(+)-glucose was 9.0mM.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.349-361
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• 2010

In this review, the current knowledge of the carbon metabolism and global carbon regulation in Corynebacterium glutamicum are summarized. C. gluamicum has phosphotransferase system (PTS) for the utilization of sucrose, glucose, and fructose. C. glutamicum does not show any preference for glucose when various sugars or organic acids are present with glucose, and thus cometabolizes glucose with other sugars or organic acids. The molecular mechanism of global carbon regulation such as carbon catabolite repression (CCR) in C. glutamicum is quite different to that in Gram-negative or low-GC Gram-positive bacteria. GlxR (glyoxylate bypass regulator) in C. glutamicum is the cyclic AMP receptor protein (CRP) homologue of E. coli. GlxR has been reported to regulate genes involved in not only glyoxylate bypass, but also central carbon metabolism and CCR including glycolysis, gluconeogenesis, and tricarboxylic acid (TCA) cycle. Therefore, GlxR has been suggested as a global transcriptional regulator for the regulation of diverse physiological processes as well as carbon metabolism. Adenylate cyclase of C. glutamicum is a membrane protein belonging to class III adenylate cyclases, thus it could possibly be a sensor for some external signal, thereby modulating cAMP level in response to environmental stimuli. In addition to GlxR, three additional transcriptional regulators like RamB, RamA, and SugR are also involved in regulating the expression of many genes of carbon metabolism. Finally, recent approaches for constructing new pathways for the utilization of new carbon sources, and strategies for enhancing amino acid production through genetic modification of carbon metabolism or regulatory network are described.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.507-511
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• 1995

In an attempt to improve the productivity of ${\beta}-galactosidase$ from Bacillus sp. A1, which was isolated from soil and has remarkably higher transgalactosylation activity than lactose hydrolysis activity, a chemical mutation procedure using N-methyl-N'-nitro-N-nitrosoguanidine followed by selection was conducted. The final selection, designated as Bacillus sp. A4442, turned out to show a substantially increased enzyme productivity. Catabolite repression by glucose and lactose requirement as an inducer for the enzyme biosynthesis, which were shown in the parent strain, was markedly diminished; instead it was found out that galactose acts as another inducer. Because pH of medium, one of the most important factors for cell growth as well as enzyme production, is closely related with the sugar concentration during culture, it was kept in the optimum range of $6.5{\sim}7.5$; for this the initial glucose concentration was adjusted to be 0.5% which was thereafter maintained by the controlled pumping-in of lactose using the pH-stat technique. By doing so, we were able to increase the productivity of ${\beta}-galactosidase$ with high transgalactosylation activity up to $44\;unit/m{\ell}-broth$.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.14-20
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• 1998

Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

• Journal of Microbiology
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• v.42 no.4
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• pp.319-327
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• 2004

An additional amylase, besides the typical $\alpha-amylase,$ was detected for the first time in the cytoplasm of B. subtilis SUH4-2, an isolate from Korean soil. The corresponding gene (bbmA) encoded a malto­genic amylase (MAase) and its sequence was almost identical to the yvdF gene of B. subtilis 168, whose function was unknown. Southern blot analysis using bbmA as the probe indicated that this gene was ubiquitous among various B. subtilis strains. In an effort to understand the physiological function of the bbmA gene in B. subtilis, the expression pattern of the gene was monitored by measuring the $\beta-galactosidase$ activity produced from the bbmA promoter fused to the amino terminus of the lacZ struc­tural gene, which was then integrated into the amyE locus on the B. subtilis 168 chromosome. The pro­moter was induced during the mid-log phase and fully expressed at the early stationary phase in defined media containing $\beta--cyclodextrin\;(\beta-CD),$ maltose, or starch. On the other hand, it was kept repressed in the presence of glucose, fructose, sucrose, or glycerol, suggesting that catabolite repression might be involved in the expression of the gene. Production of the $\beta-CD$ hydrolyzing activity was impaired by the spo0A mutation in B. subtilis 168, indicating the involvement of an additional regu­latory system exerting control on the promoter. Inactivation of yvdF resulted in a significant decrease of the $\beta-CD$ hydrolyzing activity, if not all. This result implied the presence of an additional enzyme(s) that is capable of hydrolyzing $\beta-CD$ in B. subtilis 168. Based on the results, MAase encoded by bbmA is likely to be involved in maltose and $\beta-CD$ utilization when other sugars, which are readily usable as an energy source, are not available during the stationary phase.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.181-187
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• 1989

Plasmid DNA was isolated from Lactobacillus casei SW-M1($Lac^{+}$strain). The curing frequencies of pPLac plasmid from L. casei SW-M1 showed 43% for acriflavin treatment and 53% for ethidium bromide treatment after 3 times transfer. On the charaterization of pPLac plasmid, it was found that the plasmid contained gene encoding phospho-$\beta$-galactosidase for lactose utilization. Lactose-PTS(phosphotransferase system)was involved in membrane transport system in $Lac^{+}$ strain. Induction of phospho-$\beta$-galactosidase was specially effective by galactose, lower effect with lactose and glucose but not by IPTG(isopropyl-$\beta$-D-thiogalactoside). This result showed that induction of phospho-$\beta$-galactosidase by IPTG did not appeared. The catabolite repression of phospho-$\beta$-galactosidase synthesis by glucose was not found in L. casei.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.128-134
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• 1991

To study the reduced growth and synthesis, proeviously reported, of ${\beta}$-galactosidase of alkalophilic Bacillus sp. YS-309 at the higher lactose concentration of 0.5% (w/v) in the medium, lactose transport and utilization were examined. The results showed that lactose transport was influenced by the addition of four kinds of antibiotics, and tetracycline stimulated most but not valinomycin. PEP-potentials of the cells grown on lactose was estimated lower than the cells on glucose and on galactose. Thus, the transport of lactose was independent of intracellular PEP and phosphorylation reactions, and was thought to be uptaked directly or oxidized in part in the transport process. In the other hand, once lactose was uptaked into the cells, it was hydrolyzed by ${\beta}$-glactosidase to glucose and galactose. The former was metabolized fast but the latter was accumulated. Galactose and lactose were not utilized until glucose was mostly depleted in the medium. The ${\beta}$-galactosidase synthesis decreased in the presence of glucose over 0.2% and galactose over 0.05 to 0.1%, respectively. In conclusion, it was considered for glucose as a repressor and galactose as a inducer for ${\beta}$-galactosidase synthesis even though the mechanisms were not elucidated. Catabolite repression of glucose on the enzyme synthesis was not relieved by the addition of exogeneous cAMP.

• Journal of Life Science
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• v.10 no.4
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• pp.397-402
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• 2000

Polyphosphate kinase catalyzes the formation of polyphosphate from ATP. To understand the mechanism of phosphate accumulation, the Serratia marcescens gene encoding ppk was cloned from the genomic library by the method of Southern hybridization. The hybridization positive DNA fragment region from pDH3 was subcloned into the expression vector. The ppk gene product, a polypeptide of 75 kDa, was confirmed by SDS-PAGE. Expression of the Serratia marcescens ppk is regulated by the catabolite repression system. The enzyme activity polyphosphate kinase was increased in the E. coli strain harboring plasmid pMH4 with ppk gene.

• 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.31 no.5
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• pp.659-666
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• 2021

After Candida albicans, Candida glabrata is one of the most common fungal species associated with candidemia in nosocomial infections. Rapid acquisition of nutrients from the host is important for the survival of pathogens which possess the metabolic flexibility to assimilate different carbon and nitrogen compounds. In Saccharomyces cerevisiae, nitrogen assimilation is controlled through a mechanism known as Nitrogen Catabolite Repression (NCR). NCR is coordinated by the action of four GATA factors; two positive regulators, Gat1 and Gln3, and two negative regulators, Gzf3 and Dal80. A mechanism in C. glabrata similar to NCR in S. cerevisiae has not been broadly studied. We previously showed that in C. glabrata, Gln3, and not Gat1, has a major role in nitrogen assimilation as opposed to what has been observed in S. cerevisiae in which both factors regulate NCR-sensitive genes. Here, we expand the knowledge about the role of Gln3 from C. glabrata through the transcriptional analysis of BG14 and gln3Δ strains. Approximately, 53.5% of the detected genes were differentially expressed (DEG). From these DEG, amino acid metabolism and ABC transporters were two of the most enriched KEGG categories in our analysis (Up-DEG and Down-DEG, respectively). Furthermore, a positive role of Gln3 in AAA assimilation was described, as was its role in the transcriptional regulation of ARO8. Finally, an unexpected negative role of Gln3 in the gene regulation of ABC transporters CDR1 and CDR2 and its associated transcriptional regulator PDR1 was found. This observation was confirmed by a decreased susceptibility of the gln3Δ strain to fluconazole.