• Korean Journal of Ecology and Environment
• /
• v.55 no.2
• /
• pp.120-131
• /
• 2022

Microcystins (MCs) are cyano-toxins mainly produced by cyanobacteria in the genera of Microcystis, Anabaena, and Oscillatoria. The concentrations of MCs in the water bodies and fish tissues taken from the four weirs (Ipo, Gangjeong-goryeong, Baekje, and Juksan) in the four main rivers in Korea, and the health risk of human due to consumption of toxin-detected fish was examined. The maximum values of MCs concentration in the water samples were as follows: Juksan (3.261 ㎍ L^-1), Gangjeong-goryeong (1.014 ㎍ L^-1), Baekje (0.759 ㎍ L^-1), and Ipo (0.266 ㎍ L^-1) weirs. The MC-RR concentration was the highest among the MCs, and MC-YR was not detected. MCs of 0.222~9.808 ㎍ g^-1 dry weight were detected in the liver of 3 out of 215 fishes of 16 species, and below the detection limit in muscle. As a result of comparing the feeding characteristics of the collected fishes and toxin concentrations in water and fish tissue, it was concluded that the biomagnification of MCs through the food chain did not occur. It was judged that there was no health risk due to the consumption of the fish detected the toxin, based on the amount of the fish intake of the Korean people and the allowable daily intake of MCs. However, in order to reduce the health risk due to MCs, further studies should be conducted to analyze the concentration of MCs contained in fish tissues collected at various times in the area dominated by harmful cyanobacteria to obtain data on the exposure of MCs due to fish consumption. In addition, it is necessary to establish the management guidelines for MCs in fish tissues.

• Microbiology and Biotechnology Letters
• /
• v.51 no.1
• /
• pp.83-92
• /
• 2023

In this study, bioconversion of rutin to quercetin was confirmed by the fermentation of Korean indigenous probiotics and tartary buckwheat. Based on whole genome sequencing of 17 probiotics species, α-rhamnosidase, related to bioconversion of isoquercetin (quercetin 3-β-D glucoside) from rutin, is identified in the genome of CBT BG7, LC5, LR5, LP3, LA1, and LGA1. β-Glucosidase, related to bioconversion of isoquercetin to quercetin, is identified in the genome of all 17 species. Among the 17 probiotics species, 6 probiotics including CBT BG7, LR5, LP3, LA1, LGA1 and ST3 performed the bioconversion of rutin to quercetin up to 21.5 ± 0.3% at 7 days after fermentation. The fermentation of each probiotics together with enzyme complex Cellulase KN^® was conducted to reduce the time of bioconversion. As a result, CBT LA1 which showed the highest yield of bioconversion of 21.5 ± 0.3% when the enzyme complex was not added showed high bioconversion yield of 84.6 ± 0.5% with adding the enzyme complex at 1 day after fermentation. In particular, CBT ST3 (96.2 ± 0.4%), SL6 (90.1 ± 1.4%) and LP3 (90.0 ± 0.4%) showed high yield of bioconversion more than 90%. In addition, such probiotics including high levels in quercetin indicated the inhibitory effects of NO production in LPS-induced RAW264.7 cells. In this study, we confirmed that the fermentation of Korean indigenous probiotics and enzyme complex together with roasted tartary buckwheat increased the content of quercetin and reduced the time of bioconversion of rutin to quercetin which is a bioactive compound related to anti-inflammatory, antioxidants, anti-obesity, and anti-diabetes.

• Korean journal of applied entomology
• /
• v.61 no.4
• /
• pp.605-614
• /
• 2022

Two major problems currently threaten human survival on Earth: climate change and the rapid aging of the population in developed countries. Climate change is a result of the increase in greenhouse gas (GHG) concentrations in the atmosphere due to the increase in the use of fossil fuels owing to economic and transportation development. The rapid increase in the age of the population is a result of the rise in life expectancy due to the development of biomedical science and technology and the improvement of personal hygiene in developed countries. To avoid irreversible global climate change, it is necessary to quickly transition from the current fossil fuel-based economy to a zero-carbon renewable energy-based economy that does not emit GHGs. To achieve this goal, the dairy and livestock industry, which generates the most GHGs in the agricultural sector, must transition to using low-carbon emission production methods while simultaneously increasing consumers' preference for low-carbon diets. Although 77% of currently available arable land globally is used to produce livestock feed, only 37% and 18% of the proteins and calories that humans consume come from dairy and livestock farming and industry. Therefore, using edible insects as a protein source represents a good alternative, as it generates less GHG and reduces water consumption and breeding space while ensuring a higher feed conversion rate than that of livestock. Additionally, utilizing the functionality of medicinal insects, such as silkworms, which have been proven to have certain health enhancement effects, it is possible to develop functional foods that can prevent or delay the onset of currently incurable degenerative diseases that occur more frequently in the elderly. Insects are among the first animals to have appeared on Earth, and regardless of whether humans survive, they will continue to adapt, evolve, and thrive. Therefore, the use of various edible and medicinal insects, including silkworms, in industry will provide an important foundation for human survival and prosperity on Earth in the near future by resolving the current two major problems.

• Journal of Wetlands Research
• /
• v.25 no.4
• /
• pp.274-283
• /
• 2023

Buffer zones, an example of nature-based solutions, offer wide range of environmental, social and economic benefits due to their multifunctionality when applied to watershed areas promoting blue-green connectivity. This study evaluated the effects of buffer zone application to the water quality of Yongdam reservoir tributaries. Particularly, the challenges and improvement of the buffer zone design were identified and suggested, respectively. Water and soil samples were collected from a total of six sites in Yongdam reservoir from September 2021 to April 2022. Water quality analyses revealed that among the sites monitored, downstream of Sangjeonmyeon Galhyeonri (SG_W_D2) was found to have the highest concentration for water quality parameters turbidity, total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN). This finding was attributed to the algal bloom observed during the sampling conducted in September and October 2021. It was found through the soil analyses that high TN and TP concentrations were also observed in all the agricultural land uses implying that nutrient accumulation in agricultural areas are high. Highest TN concentration was found in the agricultural area of Jeongcheonmyeon Wolpyeongri (JW_S_A) followed by Jucheonmyeon Sinyangri (JS_S_A) while the lowest TN concentration was found in the original soil of Sangjeonmyeon Galhyeonri (SG_S_O). Among the types of buffer zones identified in this study, Type II-A, Type II-B and Type III were found to have blue-green connectivity. However, initially, blue-green connectivity in these buffer zone types were not considered leading to poor design and poor performance. As such, improvement in the design considering blue-green network and renovation must be considered to optimize the performance of these buffer zones. The findings in this study is useful for designing buffer zones in the future.

• Korean Journal of Environmental Biology
• /
• v.41 no.3
• /
• pp.179-192
• /
• 2023

In this study, changes in the microbial ecosystem of the Yeongheungdo island coastal waters were investigated for five years to collect basic data. To evaluate the influence of distance from the coast on the microbial ecosystem, four sites, coastal Site (S1) and 0.75, 1.5, and 3 km away from the coast, were set up and the changes in physicochemical and biological factors were monitored. The results showed seasonal changes in water temperature, dissolved oxygen, salinity, and pH but with no significant differences between sites. For nutrients, the concentration of dissolved inorganic nitrogen increased from 6.4 μM in April-June to 16.4 μM in July-November, while that of phosphorus and silicon phosphate increased from 0.4 μM and 2.5 μM in April-June to 1.1 μM and 12.0 μM in July-November, respectively. Notably, phosphorus phosphate concentrations were lower in 2014-2015 (up to 0.2 μM) compared to 2016-2018 (up to 2.2 μM), indicating phosphorus limitation during this period. However, there were no differences in nutrients with distance from the coast, indicating that there was no effect of distance on nutrients. Phytoplankton (average 511 cells mL^-1) showed relatively high biomass (up to 3,370 cells mL^-1) in 2014-2015 when phosphorus phosphate was limited. Notably, at that time, the concentration of dissolved organic carbon was not high, with concentrations ranging from 1.1-2.3 mg L^-1. However, no significant differences in biological factors were observed between the sites. Although this study revealed that there was no disturbance of the ecosystem, further research and more basic data on the microecosystem are necessary to understand the ecosystem of the Incheon.

• Microbiology and Biotechnology Letters
• /
• v.51 no.4
• /
• pp.465-473
• /
• 2023

In this study, we aimed to evaluate the bioconversion ability of single (Lactiplantibacillus plantarum CBT LP3, Lactococcus lactis subsp. lactis CBT SL6, Streptococcus thermophilus CBT ST3) and multi-strain probiotics to convert rutin to quercetin in roasted tartary buckwheat, and to assess their biological activities. To evaluate the bioconversion efficiency, each strain was cultured for 24 h in MRS media with 5% roasted tartary buckwheat 'Hwangguem-Miso' powder. After then, rutin and quercetin contents were determined by HPLC. Additionally, the biological activities were compared before and after bioconversion of an ingredient. Anti-oxidant effects were measured by DPPH and ABTS assays. Anti-inflammatory effects were determined by measuring NO production, and levels of iNOS, TNF-α, IL-6 and IL-4 using an LPS-induced Raw 264.7 cell model. The bioconversion rate under the combination of three species of probiotics significantly increased more than single species. Antioxidant efficacy results showed the highest activity when the combination of three species of probiotics cultured. The pro-inflammatory factors such as nitric oxide, iNOS, TNF-a, and IL-6 were significantly decreased when the three types of probiotics were combined than single strain was cultured. In addition, level in the anti-inflammatory factor IL-4 was increased. The multi-strain probiotics showed increased bioconversion efficiency, effects of anti-oxidant and anti-inflammatory compared to the single strain. These findings suggest that the fermentation of tartary buckwheat by probiotics may be a valuable candidate for developing functional foods with anti-oxidation and anti-inflammation.

• Food Science and Preservation
• /
• v.30 no.1
• /
• pp.78-87
• /
• 2023

This study was conducted to evaluate the effect of different 1-methylcyclopropene (1-MCP) concentrations on fruit quality of small-sized RubyS apples during cold storage. After harvesting, the fruits were treated with 1-MCP at 0.5 or 1 µL/L concentrations and, subsequently, stored at 0℃ for 6 months. After 6 months, the flesh firmness of untreated fruits, which was 85.4 N at harvest, had gradually decreased to 46.5 N; however, that of 1-MCP-treated fruits was maintained at 59.1 and 59.5 N. Titratable acidity (TA) of untreated fruits had also decreased from 0.42 to 0.24%, whereas that of 1-MCP-treated fruits was maintained at 0.26 and 0.27%. Soluble solids content (SSC) did not differ in all fruits. However, the 1-MCP-treated fruits had lower levels of SSC/TA ratio than untreated fruits. Moreover, after 6 months, the ethylene production had increased to 47.0 µL/kg/h in the untreated fruits, whereas 1-MCP blocked the ethylene production at 1.4 and 1.7 µL/kg/h. The weight loss and peel color variables remained unaffected by 1-MCP treatments. Thus, these results indicated that, for RubyS apples, the storability was only 2 months at 0℃ without treatment, which can be extended to 6 months with 1-MCP treatments. The application of 1-MCP at 0.5 µL/L concentration is effectively and economically sufficient to maintain the quality of RubyS apples.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.3
• /
• pp.363-373
• /
• 2010

"Curve number" (CN) indicates the runoff potential of an area. The US Soil Conservation Service (SCS)'s CN method is a simple, widely used, and efficient method for estimating the runoff from a rainfall event in a particular area, especially in ungauged basins. The use of soil maps requested from end-users was dominant up to about 80% of total use for estimating CN based rainfall-runoff. This study introduce the use of soil maps with respect to hydrologic and watershed management focused on hydrologic soil group and a case study resulted in assessing effective rainfall and runoff hydrograph based on SCS-CN method in a small watershed. The ratio of distribution areas for hydrologic soil group based on detailed soil map (1:25,000) of Korea were 42.2% (A), 29.4% (B), 18.5% (C), and 9.9% (D) for HSG 1995, and 35.1% (A), 15.7% (B), 5.5% (C), and 43.7% (D) for HSG 2006, respectively. The ratio of D group in HSG 2006 accounted for 43.7% of the total and 34.1% reclassified from A, B, and C groups of HSG 1995. Similarity between HSG 1995 and 2006 was about 55%. Our study area was located in Sosu-myeon, Goesan-gun including an approx. 44 $km^2$-catchment, Chungchungbuk-do. We used a digital elevation model (DEM) to delineate the catchments. The soils were classified into 4 hydrologic soil groups on the basis of measured infiltration rate and a model of the representative soils of the study area reported by Jung et al. 2006. Digital soil maps (1:5,000) were used for classifying hydrologic soil groups on the basis of soil series unit. Using high resolution satellite images, we delineated the boundary of each field or other parcel on computer screen, then surveyed the land use and cover in each. We calculated CN for each and used those data and a land use and cover map and a hydrologic soil map to estimate runoff. CN values, which are ranged from 0 (no runoff) to 100 (all precipitation runs off), of the catchment were 73 by HSG 1995 and 79 by HSG 2006, respectively. Each runoff response, peak runoff and time-to-peak, was examined using the SCS triangular synthetic unit hydrograph, and the results of HSG 2006 showed better agreement with the field observed data than those with use of HSG 1995.

• Journal of Food Hygiene and Safety
• /
• v.27 no.1
• /
• pp.42-49
• /
• 2012

This study was carried out to investigate the toxicity of food Red No.2 in the Sprague-Dawley (SD) female rat for 4 weeks. SD rats were orally administered for 28 days, with dosage of 500, 1,000, 2,000 mg/kg/day. Animals treated with food Red No.2 did not cause any death and show any clinical signs. They did not show any significant changes of body weight, feed uptake and water consumption. There were not significantly different from the control group in urinalysis, hematological, serum biochemical value and histopathological examination. In conclusion, 4 weeks of the repetitive oral medication of food Red No.2 has resulted no alteration of toxicity according to the test materials in the group of female rats with injection of 2,000 mg/kg. Therefore, food Red No.2 was not indicated to have any toxic effect in the SD rats, when it was orally administered below the dosage 2,000 mg/kg/day for 4 weeks.