• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.131-137
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• 2001

Previous work has identified that only the catabolite responsive element A (creA; previously called cre-2) out of two potential cre sequences (cre-1: nucleotide +160 to +173 and cre-2: +173 to +186), recognized within the coding region of the xylanaseA gene (xynA) of Bacillus stearothermophilus No.236, was actually, was actually involved in the carbon catabolite repression(CCR) of xynA expression in B. subtilis. However, the level of CCR of xynA expression in the original B.stearothermophilus No.236 strain (70-fold repression). Therefore, to search for an additional cre element in the promoter region, the upstream region of the xynA gene was subcloned by chromosome walking, and as a result, another potential cre element (nucleotide -124∼-137; designated creB) was recognized in this region. The cre-like sequence revealed a high homology to the cre consensus sequence. The xylanase activity of B. subtilis MW15 bearing pWPBR14 (containing creA and creB) cultured in a medium containing xylose as the sole carbon source was about 7.7 times higher than that observed for the same culture containing glucose. B. subtilis MW15 bearing pWPBR23 (containing only creA) produced an activity about 2.4 times higher. This pattern of CCR was confirmed using derivatives of xynA::aprA fusion plasmids. Furthermore, a measurement of the amounts of the xynA transcript showed a similar pattern as that for the production of xylanase. In addition, the synthesis of xylanase in B. subtilis QB7115 [a catabolite control protein A (ccpA) mutant strain] carrying pWPBR14 was almost completely relieved from glucose repression. Together, these results lead to a conclusion that the CCR of the expression of the xynA gene is mediated by CcpA binding at creA and creB sites in B. subtilis.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.147-159
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• 2018

Genetically engineered mouse models are commonly preferred for studying the human disease due to genetic and pathophysiological similarities between mice and humans. In particular, Cre-loxP system is widely used as an integral experimental tool for generating the conditional. This system has enabled researchers to investigate genes of interest in a tissue/cell (spatial control) and/or time (temporal control) specific manner. A various tissue-specific Cre-driver mouse lines have been generated to date, and new Cre lines are still being developed. This review provides a brief overview of Cre-loxP system and a few commonly used promoters for expression of tissue-specific Cre recombinase. Also, we finally introduce some available links to the Web sites that provides detailed information about Cre mouse lines including their characterization.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.109-117
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• 2020

Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TAT-Cre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TAT-Cre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TAT-Cre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.

• Journal of Medicine and Life Science
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• v.20 no.2
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• pp.67-72
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• 2023

Carbapenem-resistant Enterobacteriaceae (CRE) infections have increased rapidly over the past decade and are recognized as a severe health threat in Korea and worldwide. This study aimed to identify the status and characteristics of CRE infection in Jeju province and provide important basic data for the prevention and management of CRE infection. A descriptive epidemiological analysis was performed on reported cases of CRE infection in Jeju Province between 2018 and 2021 using the integrated management system for disease, an infectious disease reporting system from the Korea Disease Control and Prevention Agency. The annual difference and distribution trends of CRE infection were analyzed using CRE isolates, carbapenemase-producing CREs (CP-CRE) and their genotypes, and the type of medical institution in Jeju Province. CRE infections steadily increased in Jeju from 2018 to 2021, and the proportion of CP-CRE among the CREs also showed a statistically significant increase each year. Among the CRE isolates, Klebsiella pneumoniae (KPC, 62.13%) was the most common, and among the CP-CRE genotypes, KPC (81.62%) showed the highest distribution and increased each year. As the distribution of CP-CRE in have increased over the past 4 years, measures to prevent the spread and outbreak of CRE infections are warranted. The results of this study are expected to be used as basic data for prevention and management of CRE infections in the province.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.76-83
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• 2016

This study investigated the quality characteristics and antioxidative activity of muffins prepared with coffee ground residue water extracts (CRE) and powder (CRP). CRE-muffins were prepared by addition of CRE (0~2.0%, w/v) to water of a basic formulation, whereas CRP-muffins were prepared by addition of CRP (0~3.0%, w/w) to the flour. The height and volume index of CRE-muffins were higher than those of control. The weight and water contents of CRE-muffins and CRP-muffins were higher than those of the control. The hardness of CRE-muffins decreased compared to the control, whereas hardness of CRP-muffins increased. The total polyphenol contents and antioxidative activity of muffin significantly increased with increasing concentrations of CRE and CRP. Muffins containing 0.5~2.0% CRE and 0.5~3.0% CRP had acceptable sensory properties (flavor, taste, texture, and overall acceptability). Therefore, this study indicated that the optimal concentrations of CRE and CRP into muffin formula are 1.0 % (w/v) and 1.0% (w/w), respectively.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.5
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• pp.104-112
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• 2017

The CRE (Cell Range Expansion) that selects the small cell with more efficient uplink resources has been developed by 3GPP to relieve the problem of the traffic imbalance due to the power differences between macro and small cells in HetNet. In addition, ABS (Almost Blank Subframes) has been proposed to resolve the signal interference problem due to the operation CREs. This paper proposes an effective method to calculate the ABS ratio by considering the proportion of the number of UEs in CRE and macro cell ranges, as well as the number of small cells in a macro cell. The proposed method has been implemented on the LTESim simulator, and compared with previously proposed methods. The experimental results show that the proposed method can improve the throughput and packet loss ratio performances. In particular, it is also shown that CRE bias values affect those performances, and there exist effective CRE bias values to derive the best performances.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.22 no.2
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• pp.50-59
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• 2009

Objectives : The aim of this study was conducted that CRE (Coptidis Rhizoma Extract) induces apoptosis in YD-10B cells, human oral squamous carcinoma cell line. Methods : In this study, YD-10B cells were exposed to CRE (0.03-0.30 mg/ml), for 6-24 hours. We measured the effects of CRE on the changes of cell viability and cell membrane, TUNEL assay of CRE-treated YD-10B cell. Results : In this study, CRE caused a decrease of viability in YD-10B cells, human oral squamous carcinoma cell line. When YD-10B cells were treated with CRE, cells showed dose-dependent manner apoptotic cell death. Conclusions : These results suggest that CRE may be potential therapeutic approach in the clinical management of oral squamous cell carcinoma.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.345-350
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• 2012

The purpose of this study was to observe the effects of Cynanchi wilfordii Radix extracts (CRE) on the improvement of the lipid compositions and blood pressure level in spontaneously hypertensive rats (SHR) fed an experimental diet for 5 weeks. The rats were divided into 3 groups: a control group, a 0.5% CRE treated group, and a 1% CRE treated group. Consumption of CRE extract for 5 weeks in SHR significantly suppressed blood pressure rise with aging (p<0.05). After eating the experimental diets, the triglycerides in serum was significantly lower in the CRE group than that in the control group. The fasting glucose levels of the 0.5% and 1% CRE group had a tendency to be lower compared with those of the control group. Total cholesterol, HDL-cholesterol and HTR (HDL-cholesterol/total cholesterol) of the SHR in the 0.5% and 1% CRE diet were significantly increased compared to the control diet. Thus, long term consumption of CRE might be beneficial in lowering high blood pressure and the improvement of lipid metabolism in SHR rats.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.584-591
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• 2022

Identifying carbapenem-resistant Enterobacteriaceae (CRE) is necessary to prevent nosocomial CRE infection outbreaks. Here, a rapid identification method with reduced enrichment time was developed without compromising accuracy. A total of 49 rectal swabs requested for CRE screening at the Department of Diagnostic Medicine at Hospital B in Busan, Korea, were included in this study. Specimens were inoculated on MacConkey and CHROMID Carba media either directly or following enrichment for 3, 6, and 24 h in 100 μl trypticase soy broth containing an ertapenem disk. The enriched cultures were further inoculated on CHROMID Carba or MacConkey media containing an ertapenem disk. In total, 19 CRE and 5 carbapenem-intermediate Enterobacteriaceae isolates were obtained from the 49 swabs. Among the 19 CRE isolates, carbapenemase-producing Enterobacteriaceae constituted 13 strains. Moreover, of the 19 CRE isolates, 16 (81.25%) and 17 (88.24%) were identified from the direct cultures on MacConkey and CHROMID Carba media, respectively. After 3 h of enrichment, the proportions of the CRE identified in the media were: MacConkey medium, 16/19 (81.25%); CHROMID Carba medium, 17/19 (88.24%); and MacConkey medium containing an ertapenem disk, 17/19 (88.24%). The detection rates after 6 h of enrichment were the same for all three media (19/19 strains, 100%), whereas those after 24 h of enrichment were 21, 22, and 24 strains, respectively, but included false positives. These findings suggest that a 6-h enrichment before inoculation on the CHROMID Carba medium is optimal for the rapid and accurate detection of CRE in clinical samples.