• Journal of Life Science
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• v.29 no.11
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• pp.1173-1178
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• 2019

The purpose of this study was to isolate an agar-degrading marine bacterium and characterize its agarase. Bacterium BK-1, from Gwanganri Beach at Busan, Korea, was isolated on Marine 2216 agar medium and identified as Agarivorans sp. BK-1 by 16S rRNA gene sequencing. The extracellular agarase, characterized after dialysis of culture broth, showed maximum activity at pH 6.0 and $50^{\circ}C$ in 20 mM Tris-HCl buffer. Relative activities at 20, 30, 40, 50, 60, and $70^{\circ}C$ were 67, 93, 97, 100, 58, and 52%, respectively. Relative activities at pH 5, 6, 7, and 8 were 59, 100, 95, and 91%, respectively. More than 90% of the activity remained after a 2 hr exposure to 20, 30, or $40^{\circ}C$; about 60% of the activity remained after a 2 hr exposure to $50^{\circ}C$. Almost all activity was lost after exposure to 60 or $70^{\circ}C$ for 30 min. Zymography revealed three agarases with molecular weights of 110, 90, and 55 kDa. Agarose was degraded to neoagarobiose (46.8%), neoagarotetraose (39.7%), and neoagarohexaose (13.5%), confirming the agarase of Agarivorans sp. BK-1 as a ${\beta}$-agarase. The neoagarooligosaccharides generated by this agarase could be used for moisturizing, bacterial growth inhibition, skin whitening, food treatments, cosmetics, and delaying starch degradation.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.255-263
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• 2019

Glycyrrhizae radix is one of the most frequently prescribed ingredients in Oriental medicine, and Glycyrrhizae radix extract has been shown to exert anti-cancer effects. However, the cellular and molecular mechanisms of programed cell death (apoptosis) by Glycyrrhizae radix are poorly defined. In the present study, it was examined the molecular mechanisms of apoptosis by water extracts of Glycyrrhizae radix (GRW) in human bladder T24 cancer cells. It was found that GRW could inhibit the cell growth of T24 cells in a concentration-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies, DNA fragmentation and increased populations of annexin-V positive cells. The induction of apoptotic cell death by GRW was connected with an up-regulation of pro-apoptotic Bax protein expression and down-regulation of anti-apoptotic proteins (Bcl-2 and Bcl-xL), and inhibition of apoptosis family proteins (XIAP, cIAP-1 and cIAP-2). In addition, apoptosis-inducing concentrations of GRW induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of PARP. GRW also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the down-regulation of total Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that GRW may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of Life Science
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• v.31 no.3
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• pp.330-337
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• 2021

This study was conducted to investigate the potential of Stewartia koreana as oral healthcare materials. The antibacterial activity of ethanol extracts from leaves and branches of S. koreana against oral bacteria was confirmed. The leaf and branch extracts (1 mg/disc) showed antibacterial activity against P. gingivalis only among several tested oral bacteria. The leaf extracts showed higher antibacterial activity, with values similar to those of chlorhexidine, which was used as a positive control. The MIC of the leaf extract against P. gingivalis was 0.4 mg/ml and showed bacteriostatic action. The inhibitory effects of the extract on biofilm formation and on gene expression related to biofilm formation by P. gingivalis were determined by biofilm biomass staining, scanning electron microscopy (SEM), and qRT-PCR analysis. The biofilm production rate and cell growth of P. gingivalis in the cultures treated with 0.2-2.0 mg/ml of S. koreana leaf extracts were significantly decreased in a concentration-dependent manner. The inhibitory effect on the formation of P. gingivalis biofilms at concentrations of 1 mg/ml was confirmed by SEM. The qRT-PCR analysis showed concentration-dependent suppression of the fimA and fimB gene expression associated with fimbriae formation in the cultures treated with 0.2-2.0 mg/ml S. koreana leaf extract. These results support the conclusion that S. koreana leaf extracts can be used as oral healthcare materials derived from natural materials, as demonstrated by the antibacterial action and inhibition of biofilm formation of P. gingivalis.

• Journal of Nutrition and Health
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• v.54 no.6
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• pp.618-630
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• 2021

Purpose: The ginger rhizome (Zingiber officinale) is widely cultivated as a spice for its aromatic and pungent components. One of its constituents, 6-hydroxydopamine (6-OHDA) is usually thought to cross the cell membrane through dopamine uptake transporters, and induce inhibition of mitochondrial respiration and the generation of intracellular reactive oxygen species (ROS). This study examines the neuroprotective effect and acetylcholinesterase (AChE) inhibitory activity of fermented ginger extracts (FGEs) on 6-OHDA induced toxicity in SH-SY5Y human neuroblastoma cells. Methods: Ginger was fermented using 2 species of Bacillus subtilis, with or without enzyme pretreatment. Each sample was extracted with 70% ethanol. Neurotoxicity was assessed by applying the EZ-Cytox cell viability assay and by measuring lactic dehydrogenase (LDH) release. Morphological changes of apoptotic cell nuclei were observed by Hoechst staining. Cell growth and apoptosis of SH-SY5Y cells were determined by Western blotting and enzyme activity analysis of caspase-3, and AChE enzymatic activity was determined by the colorimetric assay. Results: In terms of cell viability and LDH release, exposure to FGE showed neuroprotective activities against 6-OHDA stimulated stress in SH-SY5Y cells. Furthermore, FGE reduced the 6-OHDA-induced apoptosis, as determined by Hoechst staining. The occurrence of apoptosis in 6-OHDA treated cells was confirmed by determining the caspase-3 activity. Exposure to 6-OHDA resulted in increased caspase-3 activity of SH-SY5Y cells, as compared to the unexposed group. However, pre-treatment with FGE inhibited the activity of caspase-3. The neuroprotective effects of FGE were also found to be caspase-dependent, based on reduction of caspase-3 activity. Exposure to FGE also inhibited the activity of AChE induced by 6-OHDA, in a dose-dependent manner. Conclusion: Taken together, our results show that FGE exhibits a neuroprotective effect in 6-OHDA treated SH-SY5Y cells, thereby making it a potential novel agent for the prevention or treatment of neurodegenerative disease.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.223-229
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• 2022

This study was conducted to investigate the effect of packaging methods and sterilization treatment on storability and microbial control in paprika fruits. When treated with chlorine dioxide gas for 3, 6, and 12 hours and cold plasma gas for 1, 3, and 6 hours, and then packed in a carton box and stored in a 8 ± 1℃ chamber for 7 days, chlorine dioxide treated 12 hours and plasma treated 6 hours was prevented the development of E·coli and YM(yeast and mold). Accordingly, the control was treated with chlorine dioxide for 12 hours and plasma for 6 hours, packed using a carton box and 40,000 cc·m^-2·day^-1·atm^-1 OTR film (MAP), and stored in a 8 ± 1℃ chamber for 20 days. Fresh weight loss rate during storage was less than 1% in the MAP treatments, and the visual quality of the MAP treatments was above the marketability limit until the end of storage. There was no difference in the contents of oxygen, carbon dioxide, and ethylene in the film. In the case of firmness, the chlorine dioxide treatments was low, and the Hunter a^* value, which showed chromaticity, was highest in the Plasma 6h MAP treatment. Off-odor was investigated in the MAP treatments, but it was very low. The rate of mold growth on the fruit stalk of paprika was the fastest and highest in the chlorine dioxide treated box packaging treatments, and the lowest in the chlorine dioxide treated MAP treatments at the end of storage. The aerobic count in the pulp on the storage end date was the lowest in the plasma treated box packaging treatments, the lowest number of E·coli in the chlorine dioxide treated MAP treatments, and the lowest yeast & mold in the chlorine dioxide treated box packaging treatments. As a result, for the inhibition of microorganisms during paprika storage, it is considered appropriate to treat plasma for 6 hours before storage regardless of the packaging method.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.85-96
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• 2023

The study involved the categorization of domestic lakes located in South Korea into three groups based on their salinity levels: upstream reservoirs with salinity less than 0.3 psu, estuarine reservoirs with salinity ranging from 0.3 to 2 psu, and brackish lagoons with salinity exceeding 2 psu. Subsequently, the research assessed variations in the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the sediment of these lakes using statistical analysis, specifically one-way analysis of variance (ANOVA). Additionally, a laboratory core incubation test was conducted to investigate the benthic nutrient fluxes in Songji lagoon (salinity: 11.80 psu), Ganwol reservoir (salinity: 0.73 psu), and Janggun reservoir (salinity: 0.08 psu) under both aerobic and anoxic conditions. The findings revealed statistically significant differences in the concentrations of T-N and T-P among sediments in the lakes with varying salinity levels (p<0.05). Further post-hoc analysis confirmed significant distinctions in T-N between upstream reservoirs and estuarine reservoirs (p<0.001), as well as between upstream reservoirs and brackish lagoons (p<0.01). For T-P, a significant difference was observed between upstream reservoirs and brackish lagoons (p<0.01). Regarding benthic nutrient fluxes, Ganwol Lake exhibited the highest diffusive flux of NH₄⁺-N, primarily due to its physical characteristics and the inhibition of nitrification resulting from its relatively high salinity. The flux of NO₃^--N was lower at higher salinity levels under aerobic conditions but increased under anoxic conditions, attributed to the impact of salinity on nitrification and denitrification. Additionally, the flux of PO₄^3--P was highest in Songji Lake, followed by Ganwol Lake and Janggun Reservoir, indicating that salinity promotes the diffusive flux of phosphate through anion adsorption competition. It's important to consider the influence of salinity on microbial communities, growth rates, oxidation-reduction processes, and nutrient binding forms when studying benthic diffusive nutrient fluxes from lake sediments.

• Journal of Life Science
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• v.33 no.4
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• pp.357-362
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• 2023

This report looks at an agar-degrading marine bacterium and characterization of its agarase. Agar-degrading marine bacterium JS-1 was isolated with Marine agar 2216 media from seawater from the seashore of Sojuk-do, Changwon in Gyeongnam Province, Korea. The agar-degrading bacterium was named as Agarivorans sp. JS-1 by phylogenetic analysis based on 16S rRNA gene sequencing. The extracellular agarase was prepared from the culture media of Agarivorans sp. JS-1 and used for characterization. Relative activities at 20℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, and 60℃ were 70%, 74%, 78%, 83%, 87%, 100%, 74%, and 66%, respectively. Relative activities at pH 5, 6, 7, and 8 were 91%, 100%, 90%, and 89%, respectively. Its extracellular agarase showed maximum activity (207 units/l) at pH 6.0 and 50℃ in 20 mM Tris-HCl buffer. The residual activity after heat treatment at 20℃, 30℃, and 50℃ for 30 minutes was 90%, 70%, and 50% or more, respectively. After a 2-hour heat treatment at 20℃, 30℃, 35℃, 40℃, and 45℃, the residual activity was 80%, 68%, 65%, 63%, and 57%, respectively. At 50℃ and above, after heat treatment for 30 minutes, the residual activity was below 60%. Thin layer chromatography analysis suggested that Agarivorans sp. JS-1 produces extracellular β-agarases as they hydrolyze agarose to produce neoagarooligosaccharides such as neoagarohexaose (20.6%), neoagarotetraose (58.5%), and neoagarobiose (20.9%). Agarivorans sp. JS-1 and its thermotolerant β-agarase would be useful in the production of neoagarooligosaccharides, showing functional activity such as inhibition of bacterial growth and delay of starch degradation.

• Journal of Life Science
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• v.33 no.11
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• pp.923-935
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• 2023

Rubus crataegifolius (RC), Ulmus macrocarpa (UM), and Gardenia jasminoides (GJ) are well-known folk medicines in Asia used to treat various gastrointestinal disturbances. The present study evaluated the gastroprotective effect of LS-RUG-com, a mixture of commercially prepared powders of RC, UM, and GJ with a ratio of 3:1:2(w/w/w) against HCl/ethanol-induced gastritis, indomethacin-induced ulcers, and esophageal reflux-induced esophageal mucosal damage and Helicobacter pylori infections. In addition, TNF-α and IL-1β expressions were also determined and measured in esophageal tissue. As to HCl/ethanol-induced gastritis, the LS-RUG-com treatment at a dose of 150 mg/kg showed a remarkable anti-gastritis effect. Regarding indomethacin-induced gastric ulcers, the LS-RUG-com treatment had a significant anti-gastric ulcer effect. Furthermore, in the gastroesophageal reflux disease (GERD) model experiment, the LS-RUG-com treatment resulted in the histological recovery of stomach damage and mucosal injuries. Furthermore, the LS-RUG-com treatment led to an increase in gastric content pH, an increase in mucus protection, and a decrease in gastric pepsin output with a significant decrease in TNF-α and IL-1β. As to the Helicobacter pylori infected animal model, LS-RUG-com had a notable inhibitory effect on Helicobacter growth. The use of RC, UM, or GJ in isolation or the LS-RUG-com treatment as whole had good effects in terms of anti-oxidation, anti-neutralization, gastric acid secretion inhibition, and anti-lipid peroxidation, which supported the use of natural products as systemic gastric protective agents. Our results suggest that the LS-RUG-com might be a significant systemic gastroprotective agent that could be utilized for the treatment and/or protection from gastric disturbances and related damage.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.119-133
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• 2011

Sulfonylurea (SU)-resistant weeds include seven annual weeds such as Monochoria vaginalis, Scirpus juncoides and Cyperus difformis, etc., and three perennial weeds of Scirpus planiculmis, Sagittaria pigmaea and Eleocharis acicularis as of 2010 since identification Monochoria korsakowii in the reclaimed rice field in 1998. The Echinochloa oryzoides resistant to acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors has been confirmed in wet-direct seeding rice field of the southern province, Korea in 2009. In the beginning of occurrence of SU-resistant weeds the M. vaginalis, S. juncoides and C. difformis were rapidly and individually spreaded in different fields, however, theses resistant weeds have been occurring simultaneously in the same filed as time goes by. The resistant biotype by weed species demonstrated about 10- to 1,000-fold resistance, base on $GR_{50}$ (50% growth reduction) values of the SU herbicides tested. And the resistant biotype of E. oryzoides to cyhalofop-butyl, pyriminobac-methyl, and penoxsulam was about 14, 8, and 11 times more resistant than the susceptible biotype base on $GR_{50}$ values. In history of paddy herbicides in Korea, the introduction of SU herbicides including besulfuron-metyl and pyrazosulfuron-ethyl that control many troublesome weeds at low use rates and provide excellent crop safety gave farmers and many workers for herbicide business refreshing jolt. The products and applied area of SU-included herbicides have been rapidly increased, and have accounted for about 69% and 96%, respectively, in Korea. The top ten herbicides by applied area were composed of all SU-included herbicides by 2003. The concentrated and successive treatment of ACCase and ALS inhibitors for control of barnyardgrass in direct-seeded rice led up to the resistance of E. oryzoides. Also, SU-herbicides like pyrazosulfuron-ethyl and imazosulfuron which are effective to barnyardgrass can be bound up with the resistance of E. oryzoides. The ALS activity isolated from the resistant biotype of M. korsakowii to SU-herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity ($I_{50}$) of the SU-resistant M. korsakowii was 14- to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of [$^{14}C$]bensulfuron uptake and translocation. ALS genes from M. vaginalis resistant and susceptible biotypes against SU-herbicides revealed a single amino acid substitution of proline (CCT), at 197th position based on the M. korsakowii ALS sequence numbering, to serin (TCT) in conserved domain A of the gene. Carfentrazone-ethyl and pyrazolate were used mainly to control SU-resistant M. vaginalis by 2006, the early period, in Korea. However, the alternative herbicides such as benzobicyclone, to be possible to control simultaneously the several resistant weeds, have been developing and using broadly because the several resistant weeds have been occurring simultaneously in the same filed. The top ten herbicides by applied area in Korea have been occupied by products of 3-way mixture type including herbicides with alternative mode of action for the herbicide resistant weeds. Mefenacet, fentrazamide and cafenstrole had excellent controlling effects on the ACCase and ALS inhibitors resistant when they were applied within 2 leaf stage.

• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.340-349
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• 2011

This study examined the roles of autolytic enzymes and microorganisms in the ripening process of salted Alaska pollack tripe made with various concentrations of salt i.e, 7.5% and 20% by weight. Salted Alaska pollack tripe treated with antibiotic agents for the inhibition of microbial growth and a control were prepared experimentally, and changes in chemical composition and viable cell counts were investigated, individually, during the ripening process. Just after the preparation of the low salt Alaska pollack tripe made with 7.5% salt, viable bacterial cells occurred at a level of $10^5$ CFU/g. In the control, bacterial counts increased rapidly to $10^7$ CFU/g by the 14th day of ripening. However, in the sample treated with antibiotic agents, counts were decreased to a level of $10^4$ CFU/g by the 3rd day of ripening and increased gradually to $10^6$ CFU/g by the 5th day of ripening, and then the same value was maintained there-after. Just after the preparation of the high salt Alaska pollack tripe made with 20% salt, viable bacterial cells occurred at a level of $10^3$ CFU/g. In both the samples treated with antibiotic agents and the control, bacterial counts decreased rapidly to $10^0$ CFU/g by the 45th day of ripening and increased gradually there-after. The content of amino type nitrogen was 76.3 mg% just after the preparation of the low salt Alaska pollack tripe made with 7.5% salt. Amino type nitrogen content was increased to 283.5 mg% by the 5th day of proper ripening in the control, but it was increased to 208.0 mg% in the sample treated with antibiotic agents. The difference in amino type nitrogen content was 75.5 mg/100 g. The content of amino type nitrogen was 57.2 mg% just after the preparation of the high salt Alaska pollack tripe made with 20% salt. Amino type nitrogen content was increased to 198.3 mg by the 60th day of proper ripening in the control, but it was increased to 162.0 mg% in the sample treated with the antibiotic agents. The difference in amino type nitrogen content was 36.3 mg/100 g. The contents of VBN and TMA-N were 102.1 mg% and 20.5 mg%, respectively, at the 7th day of ripening in the low salt Alaska pollack tripe made with 7.5% salt. The content of VBN was 60.0 mg% and TMA-N was not detected at the 21st day of ripening in the sample treated with antibiotic agents. The control sample was spoiled by the 7th day of ripening but the sample treated with antibiotic agents was not spoiled by the 21st day of ripening. On the other hand, VBN content was 37.2 mg% and TMA-N was not detected at the 90th day of ripening in the high salt Alaska pollack tripe made with 20% salt, and the control sample was not spoiled.