• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.566-570
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• 1990

Regulation of $\beta$ -galactosidase formation was studied with Lactobacillus sporogenes. Synthesis of the enzyme was effectively induced by isopropyl- $\beta$-D-thiogalactopyranoside (IPTG) or galactose, and to a much lower level by lactose. When 15 mM glucose was added at the different intervals to the cultures that had been in contact with IPTG, the same levels of inhibition of the enzyme synthesis were observed (approximately one-third the differential rate of a control culture without glucose). This suggests that glucose did not interfere with the entry of the inducer into the cells, but interfere with the formation of $\beta$ -galactosidase through catabolite repression. The glucose inhibitory effect was not overcome by adding CAMP or cGMP to the culture media.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.514-523
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• 2017

Carbon catabolite repression is a crucial regulation mechanism in microorganisms, but its characteristic in Rhizopus is still unclear. We extracted a carbon regulation gene, cre, that encoded a carbon catabolite repressor protein (CRE) from Rhizopus stolonifer TP-02, and studied the regulation of CRE by real-time qPCR. CRE responded to glucose in a certain range, where it could significantly regulate part of the cellulase genes (eg, bg, and cbh2) without cbh1. In the comparison of the response of cre and four cellulase genes to carboxymethylcellulose sodium and a simple carbon source (lactose), the effect of CRE was only related to the concentration of reducing sugars. By regulating the reducing sugars to range from 0.4% to 0.6%, a glucose-containing medium with lactose as the inducer could effectively induce cellulases without the repression of CRE. This regulation method could potentially reduce the cost of enzymes produced in industries and provide a possible solution to achieve the largescale synthesis of cellulases.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.293-298
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• 1986

Sisomicin, which is one of aminoglycoside antibiotics, was produced by Micromonospora inyoensis. The effects of carbon sources on sisomicin production were studied in batch cultures. Starch, dextrin and maltose were good carbon sources for the production of sisomicin. However, when glucose was used, the antibiotic productivity decreased significantly due to a carbon catabolite regulation. The carbon catabolite regulation depends mostly on carbon catabolite repression, but not on carbon catabolite inhibition. On the other hand, the growth-production curves of batch cultures show that sisomicin is produced most actively during the idiophase.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.41-46
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• 2014

The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (${\alpha}$-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with ${\alpha}$-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, ${\alpha}$-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.126-130
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• 2002

Regulation of invertase biosynthesis was studied in thermophilic and alkalophilic Bacillus sp. TA-11. Biosynthesis of the invertase was effectively induced in the presence of 10 mM sucrose for 180 min. Glucose repressed the invertase induction by sucrose and as late as addition time of glucose, the invertase formation was increased, indicating that glucose repression was occurred by inducer exclusion. Catabolite repression was reduced a little by the addition of cAMP for 180 min of induction.

• 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.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.91-95
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• 1992

The hydrolyzates of lignocellulosic biomass contain a mixture of glucose, xylose and cellobiose. The yeast which can produce ethanol efficiently from xylose and cellobiose was selected and its growth and ethanol formation behavior on each sugar and their mixture were investigated. Ethanol yields during batch culture of Pichia stipitis CBS 5776 were 0.4. 0.36 and 0.23 g/g substrate on glucose, xylose and cellobiose, respectively. Mixed sugar fermentation data indicate that glucose causes catabolite regulation on xylose and cellobiose utilization. However, xylose and cellobiose were utilized simultaneously. Ethanol yields on mixtures of sugars were generally additive for each of the substrates.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.1
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• pp.59-62
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• 2014

Glucose uptake plays a pivotal role in maintaining whole body glucose homeostasis in adipocytes and skeletal muscles. In the present study we have shown that Fructus Piperis Longi Extracts (FPLE) can stimulate glucose uptake in OP9 adipocytes. The increasing effects of FPLE on glucose uptake were inhibited by compound C pretreatment, which means that the glucose uptake effects by FPLE were carried out by AMP-activated protein kinase (AMPK) activation. Further studies revealed that FPLE stimulated glucose transport occurs through a mechanism involving extracellular signal-regulated kinase (ERK1/2) activation.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.496-510
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• 2007

This paper describes the use of a discrete mathematical model to represent the basic mechanisms of regulation of the bacteria E. coli in batch fermentation. The specific phenomena studied were the changes in metabolism and genetic regulation when the bacteria use three different carbon substrates (glucose, glycerol, and acetate). The model correctly predicts the behavior of E. coli vis-a-vis substrate mixtures. In a mixture of glucose, glycerol, and acetate, it prefers glucose, then glycerol, and finally acetate. The model included 67 nodes; 28 were genes, 20 enzymes, and 19 regulators/biochemical compounds. The model represents both the genetic regulation and metabolic networks in an integrated form, which is how they function biologically. This is one of the first attempts to include both of these networks in one model. Previously, discrete mathematical models were used only to describe genetic regulation networks. The study of the network dynamics generated 8 $(2^3)$ fixed points, one for each nutrient configuration (substrate mixture) in the medium. The fixed points of the discrete model reflect the phenotypes described. Gene expression and the patterns of the metabolic fluxes generated are described accurately. The activation of the gene regulation network depends basically on the presence of glucose and glycerol. The model predicts the behavior when mixed carbon sources are utilized as well as when there is no carbon source present. Fictitious jokers (Joker1, Joker2, and Repressor SdhC) had to be created to control 12 genes whose regulation mechanism is unknown, since glycerol and glucose do not act directly on the genes. The approach presented in this paper is particularly useful to investigate potential unknown gene regulation mechanisms; such a novel approach can also be used to describe other gene regulation situations such as the comparison between non-recombinant and recombinant yeast strain, producing recombinant proteins, presently under investigation in our group.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.13-17
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• 1992

Regulation of $\beta$-galactosidase biosynthesis was studied with alkalophilic, thermophilic Bacillus sp. TA-11. Biosynthesis of the enzyme was effectively induced by lactose and some low level by isoprophyl-$\beta$-D-thiogalactopyranoside(IPTG). When 30mM glucose was added at the different intervals to the culture that had been in contact with lactose, the different levels of the enzyme synthesis were observed. So, this suggests that glucose interfered with the entry of the lactose into the cells.The glucose inhibitory effect was not relieved by adding cAMP to the culture.