• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.387-390
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• 2009

Microbial UDP-glycosyltransferases can convert many small lipophilic compounds into glycons using uridine-diphosphate-activated sugars. The glycosylation of flavonoids affects solubility, stability, and bioavailability. The gene encoding the UDP-glycosyltransferase from Bacillus cereus, BcGT-3, was cloned by PCR and sequenced. BcGT-3 was expressed in Escherichia coli BL21(DE3) with a glutathione S-transferase tag and purified using a glutathione S-transferase affinity column. BcGT-3 was tested for activity on several substrates including genistein, kaempferol, luteolin, naringenin, and quercetin. Flavonols were the best substrates for BcGT-3. The enzyme dominantly glycosylated the 3-hydroxyl group, but the 7-hydroxyl group was glycosylated when the 3-hydroxyl group was not available. The kaempferol reaction products were identified as kaempferol-3-O-glucoside and kaempferol-3,7-O-diglucoside. Kaempferol was the most effective substrate tested. Based on HPLC, LC/MS, and NMR analyses of the reaction products, we conclude that BcGT-3 can be used for the synthesis of kaempferol 3,7-O-diglucose.

• Journal of Photoscience
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• v.9 no.2
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• pp.225-228
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• 2002

Bcl-2 is a member of large bcl-2 family and protects cells from apoptosis. Using bcl-2-expressing adenovirus vector (Ad-bc1-2), we investigated the effect of bc1-2 on UVB-induced apoptosis. Adenovirus vector efficiently introduced bc1-2 gene in cultured normal mouse keratinocytes (NMK cells); almost all NMK cells (lx10$^{6}$ ) were transfected at Ixl0$^{8}$ PFU/ml. Bcl-2-transfected NMK cells were significantly resistant to UVB-induced apoptosis with the suppressive effect dependent on bcl-2-expression level. Following UVB irradiation caspase 8, 3, 9 activities were stimulated in NMK cells, while in bc1-2-transfected cells, only caspase 8, but not caspase 3 or 9 activities were stimulated. In order to investigate the effect of bc1-2 in vivo, topical application of Ad-bc1-2 on tape-stripped mouse skin was performed. Following the application, Bc1-2 was efficiently overexpressed in almost all viable keratinocytes. The expression was transient with the maximal expression of Bc1-2 at 1st day following the application of lxl0$^{9}$ PFU in 200ml. The introduced Bc1-2 remained at least for 6 days. UVB irradiation (1250 J/m$^2$) induced apoptosis within 12 h and the maximal effect was observed at 24 h in control mouse skin. Bc1-2-transfected mice skin were resistant to UVB-induced apoptosis. Topical application of empty adenovirus vector alone had no effect on Bc1-2 expression or UVB-induced apoptosis. These results indicate that adenovirus vector is an efficient gene delivery system into keratinocytes and that Bcl-2 is a potent inhibitor of UVB-induced apoptosis both in vitro and in vivo.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.571-578
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• 2009

$PM_{2.5}$ black carbon (BC) concentrations were measured to investigate the filter spot loading effect in raw BC data at 5-minute time-based resolution using a single-wavelength aethalometer at a Gwangju site. Also the elemental carbon (EC) concentrations from 24-hr integrated filter-based measurements of $PM_{2.5}$ particles were determined to compare with the loading compensated BC values. Close examination of the time-series BC data showed clearly the "gaps" when the filter tape advances, suggesting the correction of raw BC data. Therefore, we calculated the average BC concentration in each range of attenuation (ATN) to decide if there was (or was not) an effect on the aethalometer data according to the loading of the filter spot. A consistent decrease of average BC concentration was found with increasing ATN values for every month, suggesting there was a consistent "spot loading effect" in the raw BC data. The loading compensated BC concentration according to a simple compensation model with loading effect was 1.01~1.15 times greater than the raw BC data. The 24-hr average concentration of EC observed during summer sampling period was about 3% higher than the original 24-hr average BC value and 2% lower than the loading compensated BC concentration.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1479-1484
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• 2022

Bacterial cellulose (BC) is gaining attention as a carbon-neutral alternative to plant cellulose, and as a means to prevent deforestation and achieve a carbon-neutral society. However, the high cost of fermentation media for BC production is a barrier to its industrialization. In this study, chestnut shell (CS) hydrolysates were used as a carbon source for the BC-producing bacteria strain, Gluconacetobacter xylinus ATCC 53524. To evaluate the suitability of the CS hydrolysates, major inhibitors in the hydrolysates were analyzed, and BC production was profiled during fermentation. CS hydrolysates (40 g glucose/l) contained 1.9 g/l acetic acid when applied directly to the main medium. As a result, the BC concentration at 96 h using the control group and CS hydrolysates was 12.5 g/l and 16.7 g/l, respectively (1.3-fold improved). In addition, the surface morphology of BC derived from CS hydrolysates revealed more densely packed nanofibrils than the control group. In the microbial BC production using CS, the hydrolysate had no inhibitory effect during fermentation, suggesting it is a suitable feedstock for a sustainable and eco-friendly biorefinery. To the best of our knowledge, this is the first study to valorize CS by utilizing it in BC production.

• Korean Management Science Review
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• v.23 no.3
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• pp.119-132
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• 2006

Since the guaranteed service quality(QoS) is spotlighted as a strategic competitive tool to Broadband Convergence Network(BcN) service providers, many scholars have dealt with QoS issues in the BcN environment. However, just a few researchers focus on end-users and most are lean toward service providers or technology itself. In this paper, therefore, we investigated how end-users could measure service quality in the BcN environment, and moreover, proposed the end-user oriented measurement guideline for BcN QoS. Through literature review and two surveys, four QoS dimensions and nineteen measurement items were derived from end-user's perspective. proposed QoS dimension and items would be utilized as meaningful tools for future BcN service.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.619-622
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• 2006

Biotransformation is a good tool to synthesize regioselective compounds. It could be performed with diverse sources of genes, and microorganisms provide a myriad of gene sources for biotransformation. We were interested in modification of flavonoids, and therefore, we cloned a putative O-methyltransferase from Bacillus cereus, BcOMT-2. It has a 668-bp open reading frame that encodes a 24.6-kDa protein. In order to investigate the modification reaction mediated by BcOMT-2, it was expressed in E. coli as a His-tag fusion protein and purified to homogeneity. Several substrates such as naringenin, luteolin, kaempferol, and quercetin were tested and reaction products were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). BcOMT-2 could transfer a methyl group to substrates that have a 3' functional hydroxyl group, such as luteolin and quercetin. Comparison of the HPLC retention time and UV spectrum of the quercetin reaction product with corresponding authentic 3'-methylated and 4'-methylated compounds showed that the methylation position was at either the 3'-hydroxyl or 4'-hydroxyl group. Thus, BcOMT-2 transfers a methyl group either to the 3'-hydroxyl or 4'-hydroxyl group of flavonoids when both hydroxyl groups are available. Among several flavonoids that contain a 3'- and 4'-hydroxyl group, fisetin was the best substrate for the BcOMT-2.

• Journal of radiological science and technology
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• v.32 no.4
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• pp.453-460
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• 2009

The purpose of this study was to determine the dose distribution and image quality according to slice thickness and BC(beam collimation) in the gantry aperture. CT scans were performed with a 64-slice MDCT(Brilliance 64, Philips, Cleveland, USA) scanner. To determine the dose distribution according to BC, a ionization chamber was placed at isocenter and 5, 10, 15, 20, 25 and 30 cm positions from the isocenter in the 12, 3, 6 and 9 o'clock directions. The dose distribution for phantom scan was also measured using CT head and body dose phantom with five holes at the center of the phantom and the positions of the 12, 3, 6 and 9 o'clock directions. The image noise measurement for different BCs was performed using an AAPM CT phantom. Water-filled block of the phantom was moved by 5 cm or 10 cm to the 12 o'clock direction, and the image noise was measured at the center of the phantom, and the points of 12, 3, 6 and 9 o'clock direction respectively. Some points were placed beyond the scan field of view (SFOV), so that measurement was not possible at that points. The results are as follows: The CTDIw showed a larger decrease as the source goes farther from the iso-center or the BC became wider. The CTDIw depends on the BC width more than the number of the channel of a detector array. The value of CTDIW decreased with increasing BC, but the value decreased 16.6~31.9% in the head phantom scan in air scan and 51.0~64.5% in the body phantom scan. The value of the noise was 3.9~5.9 in the head and 5.3~7.4 in the body except for BC of $2{\times}0.5\;mm$, regardless of the degree of deviation from the iso-center. When a subject was located within the SFOV, the position did not significantly affect image quality even if the subject was out of the center.

• The Korean Journal of Food And Nutrition
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• v.37 no.1
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• pp.30-39
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• 2024

Black chestnut (BC) was obtained through aging of fresh chestnut (FC) at 80℃ for 15 days. Proximate and mineral compositions along with colors of FC and BC were evaluated. With aging, moisture contents decreased by 50%, whereas sugar contents, carbohydrate contents, and calories increased. Contents of minerals (Fe, P, Ca, Na, Mg, K) were significantly higher in FC than in BC, showing an order of Mg < Ca < P < K in both FC and BC. Using a Hunter color system, it was found that lightness (L), redness (a), and yellowness (b) values of FC were higher than those of BC. Antioxidant and cytotoxic activities of hot water and ethanol (50, 80, 100%) extracts prepared from FC and BC were evaluated. Extraction yields were lower with FC than with BC. Among water and ethanol extracts, water extract showed the highest DPPH radical scavenging activity for both FC and BC. IC₅₀ values for ABTS+ radical scavenging activities increased after aging. Cytotoxicities of FC and BC extracts were similar to each other. They were different against various cell lines (3T3, HeLa, and Sarcoma-180). These results suggest that BC could be used as a new processed food using chestnut.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.5
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• pp.727-734
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• 2018

In this study, real-time absorption coefficients of carbonaceous species in $PM_{2.5}$ was observed using a dual-spot 7-wavelength Aethalometer between November 1, 2016 and December 31, 2017 at an urban site of Gwangju. In addition, 24-hr integrated $PM_{2.5}$ samples were simultaneously collected at the same site and analyzed for organic carbon and elemental carbon (OC and EC) using the thermal-optical transmittance protocol. A main objective of this study was to estimate mass absorption cross section (MAC) values of black carbon (BC) particles at the study site using the linear regression between aethalometer-based absorption coefficient and filter-based EC concentration. BC particles observed at 880 nm is mainly emitted from combustion of fossil fuels, and their concentration is typically reported as equivalent BC concentration (eBC). eBC concentration calculated using MAC value of $7.77m^2/g$ at wavelength of 880 nm, which was proposed by a manufacturer, ranged from 0.3 to $7.4{\mu}g/m^3$ with an average value of $1.9{\pm}1.2{\mu}g/m^3$, accounting for 7.3% (1.5~20.9%) of $PM_{2.5}$. The relationship between aerosol absorption coefficients at 880 nm and EC concentrations provided BC MAC value of $15.2m^2/g$, ranging from 11.4 to $16.2m^2/g$. The eBC concentrations calculated using the estimated MAC of $15.2m^2/g$ were significantly lower than those reported originally from aethalometer, and ranged from 0.2 to $3.8{\mu}g/m^3$, with an average of $1.0{\pm}0.6{\mu}g/m^3$, accounting for 3.7% of $PM_{2.5}$ (0.8~10.7%). Result from this study suggests that if the MAC value recommended by the manufacturer is applied to calculate the equivalent BC concentration and radiative forcing due to BC absorption, they would result in significant errors, implying investigation of an unique MAC value of BC particles at a study site.