• ALGAE
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• v.32 no.2
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• pp.101-130
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• 2017

The ichthyotoxic Cochlodinium polykrikoides red tides have caused great economic losses in the aquaculture industry in the waters of Korea and other countries. Predicting outbreak of C. polykrikoides red tides 1-2 weeks in advance is a critical step in minimizing losses. In the South Sea of Korea, large C. polykrikoides red tide patches have often been recorded offshore and transported to nearshore waters. To explore the processes of offshore C. polykrikoides red tides, temporal variations in 3-dimensional (3-D) distributions of red tide organisms and environmental parameters were investigated by analyzing 4,432 water samples collected from 2-5 depths of 60 stations in the South Sea, Korea 16 times from May to Nov, 2014. In the study area, the vegetative cells of C. polykrikoides were found as early as May 7, but C. polykrikoides red tide patches were observed from Aug 21 until Oct 9. Cochlodinium red tides occurred in both inner and outer stations. Prior to the occurrence of large C. polykrikoides red tides, the phototrophic dinoflagellates Prorocentrum donghaiense (Jun 12 to Jul 11), Ceratium furca (Jul 11 to Aug 21), and Alexandrium fraterculus (Aug 21) formed red tides in sequence, and diatom red tides formed 2-3 times without a certain distinct pattern. The temperature for the optimal growth of these four red tide dinoflagellates is known to be similar. Thus, the sequence of the maximum growth rates of P. donghaiense > C. furca > A. fraterculus > C. polykrikoides may be partially responsible for this sequence of red tides in the inner stations following high nutrients input in the surface waters because of heavy rains. Furthermore, Cochlodinium red tides formed and persisted at the outer stations when $NO_3$ concentrations of the surface waters were < $2{\mu}M$ and thermocline depths were >20 m with the retreat of deep cold waters, and the abundance of the competing red-tide species was relatively low. The sequence of the maximum swimming speeds and thus potential reachable depths of C. polykrikoides > A. fraterculus > C. furca > P. donghaiense may be responsible for the large C. polykrikoides red tides after the small blooms of the other dinoflagellates. Thus, C. polykrikoides is likely to outgrow over the competitors at the outer stations by descending to depths >20 m and taking nutrients up from deep cold waters. Thus, to predict the process of Cochlodinium red tides in the study area, temporal variations in 3-D distributions of red tide organisms and environmental parameters showing major nutrient sources, formation and depth of thermoclines, intrusion and retreat of deep cold waters, and the abundance of competing red tide species should be well understood.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.458-464
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• 2016

Mulberry is considered a healthy food for antioxidants and many other beneficial nutrients. However, food safety concerns exist as this commodity scarcely passes through a sanitizing step due to the fragile nature of mulberry fruits. Fermented mulberry wort is one traditional way to utilize and preserve mulberries by mixing with sugars although hygienic practices are not often implemented. The purpose of this study was to investigate the fate of foodborne pathogens in fermented mulberry wort. Microbial population of inoculated E. coli in mulberry wort showed a decreasing pattern as the fermentation progressed. A quicker decrease was observed in the mulberry wort mixed with sugar at 1 to 0.8 ratio (w/w, mulberry: sugar) compared to 1 to 1 ratio, which could be due to the amount of acids generated during the fermentation process. When fully-fermented mulberry wort was contaminated with foodborne pathogens, they all decreased in population although their deceasing patterns varied depending on the species of tested bacteria. Steep deceases in population of inoculated foodborne pathogens were observed when the fermented wort was stored at $30^{\circ}C$ in comparisons to the other storage temperature, 5 and $20^{\circ}C$, regardless of bacterial species. This study necessitates the optimization of a sanitizing process during fermentation and storage of mulberry wort.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.183-201
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• 2018

The tolerance of Korean benthic macroinvertebrates to organic pollution has been analyzed since the early 1990s. However, considering the fact that there have been related studies carried out in some European countries since the early 20th century, the history of the research in Korea is very short and there is still much knowledge to supplement. We revised the saprobic valency, the saprobic value and the indicator weight value of 190 benthic macroinvertebrates taxa through the data of water quality and individual abundance collected from 7,086 sampling units in Korea from 2008 to 2014. The individual abundance of Uracanthella (Ephemeroptera) as a representative, one of the most common and abundant taxa in Korea, showed a typical lognormal distribution to 5-day biochemical oxygen demand (BOD5) concentration, and a normal distribution to the class interval of BOD5 concentration according to saprobic series. The value combining the mean individual abundance and the relative frequency of occurrence was a more efficient indicator value than that of each property alone. Benthic Macroinertebrates Index (BMI) was newly proposed as a modification of the saprobic index of Zelinka and Marvan (1961). BMI showed extremely significant correlation (determination coefficient $r^2$ > 0.6, n = 569 sites) with the concentration of BOD5, and the coefficient was a little higher than those of the previous indices. Until now, there has been very little research on the assessment of biological integrity of benthic macroinvertebrates community in Korea. While continuing researches into improve the reliability of BMI, it is necessary to develop multimetric indices for evaluating the integrity, including the composition of species and functional guilds, and the richness and diversity of the community.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.191-199
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• 2018

This study was to investigate the occurrence patterns of paddy weeds, their resistance levels to an ALS inhibiting herbicide, and to estimate the areas of resistance in these paddy fields. We used soil collected from 358 paddy fields of Jeonnam province in 2017. Based on their life cycles, weeds were 96% annuals and 4% perennial. Additionally, according to morphological classification, 59% were broad leaves, 28% were sedges and 13% were grasses. Different areas within Jeonnam province contained different numbers and occurrence rates of weed species. However, generally, we observed Lindernia dubia var. dubia, Monochoria vaginalis var. plantaginea, Ludwigia prostrata, L. procumbens, Cyperus difformis, Scirpus juncoides, Eleocharis Kuroguwai, Echinochloa oryzoides, and E. crus-galli var. echinata. We also observed seven weeds resistant to an ALS inhibiting herbicide. They were M. vaginalis, S. juncoides, C. difformis, L. dubia, Ludwigia prostrata, E. oryzoides, and E. crus-galli var. echinata. Although there were differences in the number and occurrence rate of resistant weed species to an ALS inhibiting herbicide among areas in Jeonnam province, the M. vaginalis, C. difformis, and S. juncoides occurred in 23 cities and counties in Jeonnam including Gwangju metropolitan city. Based on the rates (52%) of resistant occurrence to an ALS inhibiting herbicide in Jeonnam province, the area of weed resistant paddy fields was estimated to be 91,543 ha.

• Journal of Chest Surgery
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• v.40 no.7 s.276
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• pp.467-472
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• 2007

Background: Lung transplantation is the definitive therapy for end stage lung disorders. The success of allogenic lung transplantation has led to an increasing shortage of donor lungs from humans, including cadavers, and attention has now turned to transplantation of lungs from other species. However, there are many biological hurdles when using organs from other species because of hyperacute rejection after discordant xenotransplantation. Material and Method: Pigs (n=6, weighing $20{\sim}30kg$ each) for the donors and mongrel dogs (n=6, weighing $20{\sim}28kg$ each) for the recipients were used in this experiment. The left kidney of a pig was perfused to a mongrel dog for 30 minutes through the femoral artery and vein of the dog, and the right kidney was perfused for 30 minutes sequentially. Then, both lungs of the pig were perfused to the dog through the pulmonary artery and left atrium with using the same time intervals. The levels of IgM and IgG were measured from the blood and specimens of the kidney and lung. Result: The average levels of serum IgM gradually decreased after the perfusion, but the average levels of serum IgG did not charge from before to after perfusion. The immunohistochemical findings revealed decreased deposition of IgG and IgM after the perfusion. Conclusion: We conclude that the levels of the serum natural antibodies would be decreased with pre-transplantation xenograft perfusion in the recipient and the occurrence rate of hyperacute rejection after transplantation would be decreased.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.355-363
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• 2015

The present work quantified the growth of young biofilm in a model distribution system that was fed with chlorinated drinking water at a hydraulic retention time of 2 h. Bacterial biofilms grew on the surface of polyvinyl chloride (PVC) slides at a specific growth rate of $0.14{\pm}0.09day^{-1}$ for total bacteria and $0.16{\pm}0.08day^{-1}$ for heterotrophic bacteria, reaching $3.1{\times}10^4cells/cm^2$ and $6.6{\times}10^3CFU/cm^2$ after 10 days, respectively. The specific growth rates of biofilm-forming bacteria were found to be much higher than those of bulk-phase bacteria, suggesting that biofilm bacteria account for a major part of the bacterial production in this model system. Biofilm isolates exhibited characteristic kinetic properties, as determined by ${\mu}_{max}$ and $K_S$ values using the Monod model, in a defined growth medium containing various amounts of acetate. The lowest ${\mu}_{max}$ value was observed in bacterial species belonging to the genus Methylobacterium, and their slow growth seemed to confer high resistance to chlorine treatment (0.5 mg/L for 10 min). $K_S$ values (inversely related to substrate affinity) of Sphingomonas were two orders of magnitude lower for acetate carbon than those of other isolates. The Sphingomonas isolates may have obligate-oligotrophic characteristics, since the lower $K_S$ values allow them to thrive under nutrient-deficient conditions. These results provide a better understanding and control of multi-species bacterial biofilms that develop within days in a drinking water distribution system.

• Journal of fish pathology
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• v.30 no.2
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• pp.89-96
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• 2017

The majority of freshwater ornamental fish are imported and distributed domestically, causing high risk of exposure to exotic pathogens and drug resistant bacteria in Korea. Aeromonas hydrophila is known as a common species of fresh water bacteria and opportunistic fish pathogen, as well as a species causing zoonotic infection. In this study, we isolated motile aeromonads from various imported freshwater ornamental fish and studied the characters of the isolates. Imported freshwater ornamental fish were purchased on day 1 after the fish were deposited in the aquarium. Bacteria were isolated from the liver, kidney and spleen of fish using 0.5% NaCl containing tryptic soy agar medium. Bacteria were grouped on the basis of their morphological characteristics. The colonies with clear zone on starch-ampicillin agar (SA agar) were tentatively identified as Aeromonas spp. Two hundred and twenty-six strains, about 70% of total isolates were assumed to be Aeromonas spp. Nine isolates were further identified based on the result of the API 20E test and PCR using primers specific for A. hydrophila 16S rRNA gene. The isolates were identified as A. hydrophila and the API 20E test showed differences in trisodium citrate, D-sucrose, D-melibiose, amygdalin and L-arabinose availability between the nine isolates and standard A. hydrophila. The susceptibilities of the isolated bacteria to 10 antibacterial agents were confirmed by the disk diffusion method. Isolated strains were found to be resistant to amoxicillin and ampicillin and sensitive to florfenicol. However, 7 isolates showed multiple drug resistances to erythromycin, oxytetracycline, nalidixic acid etc. Pathogenicity of the isolates was determined by the artificial challenge test on goldfish (Carassius auratus). Three isolates caused 60 ~ 80% mortality in goldfish within 5 days after the initiation of challenge. These results indicate that multiple drug resistant, highly pathogenic and exotic A. hydrophila can spread to domestic aquarium and the preventive treatment of fish before sale is necessary.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.

• Journal of Life Science
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• v.30 no.4
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• pp.370-378
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• 2020

This study aimed to investigate the hepatoprotective effect of Dendropanax morbifera (D. morbifera) leaf hot-water extract on carbon tetrachloride (CCl₄)-treated HepG2 cells. Treatment with D. morbifera leaf hot-water extract increased the cell viability of CCl₄-treated HepG2 cells without inducing cytotoxicity. The levels of alanine transaminase (ALT) and aspartate transaminase (AST) released by CCl₄-treated cells were 27.6 U/L and 52.4 U/L, respectively, and were significantly higher than those in untreated control cells (10.0 U/L and 15.2 U/L, respectively). Moreover, the level of γ-glutamyl transpeptidase (GGT) was 5.4 times higher, while that of glutathione was 44.0% lower in CCl₄-treated cells than in control cells. However, treatment with D. morbifera leaf hot-water extract resulted in a dose-dependent decrease in the levels of ALT, AST, and GGT, and an increase in the level of glutathione. Moreover, the malondialdehyde (MDA) content in CCl₄-treated HepG2 cells was effectively reduced after treatment with D. morbifera leaf hot-water extract. Additionally, overproduction of intracellular lipids induced by CCl₄ treatment was effectively inhibited by D. morbifera leaf hot-water extract treatment. Furthermore, DCFDA staining showed that overproduction of reactive oxygen species (ROS) induced by CCl₄ treatment was effectively reduced by treatment with D. morbifera leaf hot-water extract. Our results indicate that owing to its beneficial effects, D. morbifera leaf extract has considerable potential as a functional food material for liver protection.

• Journal of Life Science
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• v.26 no.1
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• pp.34-41
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• 2016

Black chokeberries (scientific name Aronia melanocarpa) have been reported to have major effects due to anti-oxidant, anti-inflammatory, and anti-cancer capabilities. In this study, we investigated the anti- wrinkle effects of A. melanocarpa, including collagenase inhibition effects and their molecular biological mechanisms, such as oxidative stress-induced matrix metalloproteinase (MMP), mitogen-activated protein (MAP) kinase, and activator protein (AP)-1 expression and/or phosphorylation. In collagenase inhibition activity, the ethyl acetate fraction of black chokeberry (AE) was 77.2% at a concentration of 500 μg/ml, which was a significant result compared to that of Epigallocatechin gallate (positive control, 83.9% in 500 μg/ml). In the reactive oxygen species (ROS) assay, the AE produced 78% of ROS in 10 μg/ml and 70% of ROS in 75 μg/ml, which was a much lower percentage than the ROS production of H₂O₂-induced CCRF S-180II cells. In the MTT assay, cell viability was increased dose-dependently with AE in H₂O₂-induced cells. In protein expression by western blot assay, the AE suppressed the expression and phosphorylation of MMPs (MMP-1, -3, -9), MAPK (ERK, JNK, and p38), and AP-1 (c-Fos and c-Jun), and expressed the pro-collagen type I in H₂O₂-induced cells. These results suggest that black chokeberries have anti-wrinkle and collagen-production effects, and they may be used in applications for material development in the functional food and cosmetic industries.