• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.125-132
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• 2007

We estimated the distribution of predator-prey interaction strengths for 12 species of herbivores (including amphipods, isopods, gastropods, and sea urchins) and made a regression model that may be applicable to other species. Laboratory experiments were used to determine per capita grazing rate (PCGR; g seaweeds/individual/day). Relationship between the biomass of individual grazers and fourth-root transformed PCGR was fitted to power curve ($y=0.2310x^{0.3290}$, r=0.8864). This finding supported that the grazing efficiency was not even as individual grazers increase in size (biomass). Therefore, the biomass-normalized PCGR was estimated and revealed that smaller size herbivores were more effective grazers. Grazing impact considering density of each taxon was calculated. The sea hare Aplysia kurodai had greatest grazing impact on the seaweed bed and the sea urchin Strongylocentrotus nudus and S. intermedius were ranked in descending order of the impact. The amount of seaweed grazed by the amphipod Elasmopus sp. (>4,000 $ind./m^2$) and Jassa falcata (>2,000 $ind./m^2$) were 3.435 and $1.697mg/m^2/day$ respectively. The combined grazing amount of herbivores was $5,045mg/m^2/day$ in the seaweed bed. Although sea hare and sea urchin had strong impacts on seaweeds, the effects of dense, smaller species could not be seen as negligible. Surprisingly, the calculated grazing potential of sea urchins with a mean density of 3 $ind./m^2$ exceeded the mean production of seaweed cultured in domestic coastal waters in Korea (ca., 5 ton/ha). Small crustaceans were also expected to consume up to 16% of the seaweed production if their densities were rising under weak predation conditions. Considering that the population density of herbivores are strongly controlled by fish, human interference like overfishing may have strong negative effects on persistence of seaweeds communities.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.205-212
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• 2009

To suggest possible to bioremediation by benthic microalgae Nitzschia sp. isolated from the Jinhae Bay, the studies investigated the effects o flight quality and quantity on the growth of Nitzschia sp. and its growth kinetics for phosphate investigated. The Nitzschia sp. was cultured under blue (450 nm), yellow (590 nm) and red wavelength (650 nm) using light emitting diode (LED) and mixed wavelengths using a fluorescent lamp. The maximum specific growth rate showed the Nitzschia sp. under blue wavelength, although photoinhibition was observed above $100\;{\mu}mol\;m^{-2}\;s^{-1}$. Mixed wavelengths were also observed by decreasing the maximum cell density from high irradiances (>$100\;{\mu}mol$ photons $m^{-2}\;s^{-1}$). The compensation photon flux density ($I_0$) calculated from the mixed wavelengths equated to a depth of 4-10 m in Jinhae Bay, and was lower in the summer season than the depth due to suspended matter (ca. 4 m). Thus, the suitable depth for maximum growth of Nitzschia sp. might be extremely limited. In the growth kinetics for phosphate, half-saturation constant ($K_s$) was similar among different wavelengths, although the maximum growth rate was varied among different wavelengths. Because the $K_s$ was high than that of the phytoplankton, Nitzschia sp. might have adapted to the high nutrient concentrations, and have effective nutrient storage in the cell quota. Thus, Nitzschia sp. may be a useful species for bioremediation of the benthic layer in polluted inner bays by means of irradiated specific wavelength as blue.

• Journal of Life Science
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• v.34 no.5
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• pp.304-312
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• 2024

This study was conducted to characterize strain Y10, isolated from discarded chicken feathers. Strain Y10 was identified as Bacillus amyloliquefaciens through phenotypic and 16S rRNA gene analysis. B. amyloliquefaciens Y10 exhibited plant growth-promoting activities, including the production of fungal cell-degrading enzymes (cellulase, lipase, protease, and pectinase), siderophores, ammonia, and indoleacetic acid. Furthermore, strain Y10 was able to inhibit the mycelial growth of several phytopathogenic fungi. When 0.1% sucrose as a carbon source and 0.05% casein as a nitrogen source were added to the basal medium, adjusted to pH 10, and cultured at 35℃, the degradation rate of chicken feathers by strain Y10 was about two times higher than that of the basal medium, with the feathers almost completely degraded in four days. Strain Y10 also degraded various keratin substrates, including duck feathers, wool, and human nails. It was confirmed that the feather hydrolyzates prepared using strain Y10 exhibited antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (EC₅₀ = 0.38 mg/ml) and superoxide dismutase-like activity (EC₅₀ = 183.7 mg/ml). These results suggest that B. amyloliquefaciens Y10 is a potential candidate for the development of bioinoculants and feed additives applicable to the agricultural and livestock industries, as well as the microbiological treatment of keratin waste.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.2
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• pp.55-63
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• 2024

Purpose: This study aimed to assess the antimicrobial efficacy of an 810-nm infrared diode laser with indocyanine green (ICG) against Staphylococcus aureus on sandblasted, large grit, and acid-etched (SLA) titanium surfaces, comparing its effectiveness with alternative chemical decontamination modalities. Materials and Methods: Biofilms of S. aureus ATCC 25923 were cultured on SLA titanium disks for 48 hours. The biofilms were divided into five treatment groups: control, chlorhexidine gluconate (CHX), tetracycline (TC), ICG, and 810-nm infrared diode laser with ICG (ICG-PDT). After treatment, colony-forming units were quantified to assess surviving bacteria, and viability was confirmed through confocal laser-scanning microscope (CLSM) imaging. Results: All treated groups exhibited a statistically significant reduction in S. aureus (P < 0.05), with notable efficacy in the CHX, TC, and ICG-PDT groups (P < 0.01). While no statistical difference was observed between TC and CHX, the ICG-PDT group demonstrated superior bacterial reduction. CLSM images revealed a higher proportion of dead bacteria stained in red within the ICG-PDT groups. Conclusion: Within the limitations, ICG-PDT effectively reduced S. aureus biofilms on SLA titanium surfaces. Further investigations into alternative decontamination methods and the clinical impact of ICG-PDT on peri-implant diseases are warranted.

• Research in Plant Disease
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• v.30 no.2
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• pp.131-138
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• 2024

The effects of five fungicides on the spore growth phase of Alternaria dauci, which causes carrot leaf blight, were tested using the spore viability assay (SVA) and agar dilution method (ADM). The average EC₅₀ values for chlorothalonil against seven isolates of A. dauci examined by SVA and ADM were 14.21 ㎍/ml and more than 100 ㎍/ml. Dithianon and folpet also had lower EC₅₀ values in SVA than in ADM, while iminoctadine trisalbesilate had lower EC₅₀ value in ADM. For fluazinam, the EC₅₀ values of SVA and ADM were 1.63 and 2.40 ㎍/ml, respectively. As EC₅₀ values of five fungicides according to the spore growth phase of A. dauci KACC 42997, the efficacy of each fungicide as chlorothalonil, dithianon, and folpet decreased when treated after spore germination rather than when treated with spores before germination. However, iminoctadine tris-albesilate was more effective when treated after spores germinated than when treated before treatment. The excellent effect of fluazinam on the pathogen was maintained until A. dauci KACC 42997 was cultured in potato dextrose broth for 6 hr and the germ tube grew beyond the size of the spore. However, when treated with iminoctadine tris-albesilate and fluazinam after culturing for 12 hr, as the EC₅₀ values of the two fungicides increased to 8.87 and 20.65 ㎍/ml, their efficacies decreased. The results of this study show that the treatment time of the fungicide should be determined by considering the effect of the fungicide on the spore growth phase of pathogens.

• Journal of Plant Biotechnology
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• v.50
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• pp.155-162
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• 2023

Radish (Raphanus sativus L.), a root vegetable grown worldwide, is consumed in several ways. In the cross between parental lines to produce F1 seeds of radish, the problem of low purity may arise because of pollen contamination. Therefore, we aimed to establish conditions for callus induction and regeneration so that in vitro cultured plants could be used for the propagation of stock seeds. The most effective hormone combination containing various concentrations of 2,4-D, TDZ, and kinetin was selected for callus induction using radish hypocotyl, and the induced calli were transferred to two types of hormone media to investigate the optimal conditions for shoot regeneration of the callus. The combination of 1 mg/L 2,4-D + 0.05 mg/L kin was the most effective for callus induction of RA2 and RA10, 1 mg/L 2,4-D + 0.1 mg/L kin + 0.025 mg/L TDZ of RA4, and 1 mg/L 2,4-D + 0.2 mg/L kin of RA30. Shoot regeneration of the RA4 callus occurred in both shoot regeneration media, but the frequency was much higher in the 5H+1B medium (1 mg/L NAA + 0.1 mg/L 2,4-D + 1 mg/L IPA + 0.02 mg/L GA3 + 2 mg/L zeatin + 1 mg/L BA). For the in vitro micropropagation of radish, the conditions selected in this study can assist in the propagation and maintenance of stock seeds to produce F1 seeds.

• Journal of Nutrition and Health
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• v.57 no.1
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• pp.53-64
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• 2024

Purpose: Mitochondria play a crucial role in preserving skeletal muscle mass, and damage to mitochondria leads to muscle mass loss. This study investigated the effects of oxypeucedanin hydrate, a furanocoumarin isolated from Angelica dahurica radix, on myogenesis and mitochondrial function in vitro and in zebrafish models. Methods: C2C12 myotubes cultured in media containing 0.1, 1, 10, or 100 ng/mL oxypeucedanin hydrate were immunostained with myosin heavy chain (MHC), and then multinucleated MHC-positive cells were counted. The expressions of markers related to muscle differentiation, muscle protein degradation, and mitochondrial function were determined by quantitative reverse transcription polymerase chain reaction. To investigate the effects of oxypeucedanin hydrate on mitochondrial dysfunction, Tg(Xla.Eef1a1:mito-EGFP) zebrafish embryos were treated with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) with or without oxypeucedanin hydrate and analyzed for mito-EGFP intensity and mitochondrial length. Results: Oxypeucedanin hydrate significantly increased MHC-positive multinucleated myotubes (≥ 3 nuclei) and increased the expression of the myogenic marker myosin heavy chain 4. However, it decreased the expressions of muscle-specific RING finger protein 1 and muscle atrophy f-box (markers of muscle protein degradation). Furthermore, oxypeucedanin hydrate enhanced the expressions of markers of mitochondrial biogenesis (peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, transcription factor a mitochondrial, succinate dehydrogenase complex flavoprotein subunit A, and cytochrome c oxidase subunit 1) and mitochondrial fusion (optic atrophy 1). However, it reduced the expression of dynamin-related protein 1 (a mitochondrial fission regulator). Consistently, oxypeucedanin hydrate reduced FOLFIRI-induced mitochondrial dysfunction in the skeletal muscles of zebrafish embryos. Conclusion: The study indicates that oxypeucedanin hydrate promotes myogenesis by improving mitochondrial function, and thus, suggests oxypeucedanin hydrate has potential use as a nutritional supplement that improves muscle mass and function.

• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.80-94
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• 2024

This study aimed to examine the morphological characteristics and variation in main traits by comparing the growth of individuals of Ecklonia cava Kjellman(Laminariales, Phaeophyceae) under an aquaculture environment. This survey was conducted from April 2018 to November 2019 at the aquafarm in Jindo-gun, Jeollanam-do(South coast of Korea). To classify the morphology of individuals in the aquaculture farm of E. cava, we investigated fourteen morphological characteristics and calculated four ratios between the measured values. Juvenile individuals showed a simple or oblong lanceolate, and at 3-4 months, a short stipe and holdfast developed, along with a bladelet that developed into the secondary blade form. At 5-7 months, secondary blades were found to develop irregularly on the primary blade. At 8-10 months, the primary blade expanded and secondary blades elongated. At 11-12 months, the secondary blades became oblong. At 13-14 months, the thallus area expanded. At 15-16 months, tertiary blades were formed, the thallus became more complex, the stipe thickened, and the holdfast widened. At 17-18 months, secondary blades clearly developed along with lobes. At 19-20 months, tertiary blades developed and became similar to mature natural blades. In the principal component analysis (PCA), the monthly population of the first year(Q1) and that of the second year(Q2) of the cultured population were divided along PC1, which is related to secondary blade morphological characteristics and the holdfast width. Q2 and natural populations are distributed in descending order of volume in Jeju(J), East Coast(E), and South Coast(S) along PC2, which is related to primary blade and stipe morphological characteristics. The results of this study were judged to offer important criteria for the development of different varieties of E. cava.

• Journal of Aquaculture
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• v.21 no.4
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• pp.203-212
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• 2008

A nutritional demand of oyster, Crassostrea gigas larva as part of research for improving of utilization of microalgae being used for the artificial oyster seed production. The change of body growth and biochemical compositions of larvae were investigated during larvae rearing in hatchery. The larvae were cultured in 60 M/T tank and fed mixture 6 different phytoplankton species, Isochrysis galbana (30%), Cheatoceros gracilis (20%), Pavlova lutheri (20%), Phaeodactylum triconutum (10%), Nannochryis oculata (10%) and Tetraselmis tetrathele (10%). The initial feeding amount was $0.3{\times}10^4cells/mL$ at three times a day to D-shaped larva and the feeding amount had been increased 30% gradually every two day since the larvae were raising. The larvae were developed from D shape to pediveliger stage for 12 days. The daily growth of shell length and hight were $5.8{\sim}30.8\;{\mu}m$ and $8.7{\sim}31.4\;{\mu}m$, respectively and weight gains were changed from D shape to pediveliger as follow: wet weight was $0.52{\sim}15.0\;{\mu}g/larva$, dry weight was $0.2{\sim}6.5\;{\mu}g/larva$, and ash free dry weight was $0.1{\sim}8.5\;{\mu}g/larva$. The larvae growth pattern shown a logarithmic phase from D shape to umbone stage but after that stage shown a exponential growth aspect. The crude protein, crude lipid and nitrogen free extract (NFE) of larvae during rearing periods were analyzed as $6.1{\sim}10.6%$, $0.6{\sim}1.1%$ and 1.0-2.7%, respectively. And the total amino acid contents of the larvae during rearing periods were in order as glutamic acid $1.26{\sim}2.24%$, aspartic acid $0.97{\sim}1.70%$, and methionine $0.12{\sim}0.33%$. Of the total fatty acid in the analyzed larvae, the saturated fatty acid (SSAFA) was decreased from 54.3% (D shaped larvae) to 17.1 % (pediveliger) as larvae development but the total mono-unsaturated fatty acid (${\Sigma}MOFA$) and Poly-unsaturated fatty acid (${\Sigma}PUFA$) were increased from 29.9% and 7.8% to 40.6% and 45.6%, respectively. By the way the each fatty acid of the larvae were composed of palmitic acid $9.89{\sim}36.95%$, oleic acid $12.17{\sim}32.29%$, linoleic acid $1.96{\sim}33.55%$, EPA $2.17{\sim}11.58%$ and DHA $1.95{\sim}4.51%$. As a result of this study, the larvae of oyster were demanded a various nutrients for healthy growth and the feeding control, expecially after umbone stage larvae are a rapidly growing time, is very important for success of artificial seed production.

• Journal of Chest Surgery
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• v.37 no.3
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• pp.210-219
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• 2004

Extracellular $K^{+}$ concentration ([ $K^{+}$]$_{0}$ ) can be increased within several mM by the efflux of intracellular $K^{+}$. To investigate the effect of an increase in [ $K^{+}$]$_{0}$ on vascular contractility, we attempted to examine whether extracellular $K^{+}$ might modulate vascular contractility, endothelium-dependent relaxation (EDR) and intracellular $Ca^2$$^{+}$ concentration ([C $a^2$$^{+}$]$_{i}$ ) in endothelial cells (EC). We observed isometric contractions in rabbit carotid, superior mesenteric, basilar arteries and movse aorta. [C $a^2$$^{+}$]$_{i}$ was recorded by microfluorimeter using Fura-2/AM in EC. No change in contractility was recorded by the increase in [ $K^{+}$]$_{0}$ from 6 to 12 mM in conduit artery such as rabbit carotid artery. whereas resistant vessels, such as basilar and branches of superior mesenteric arteries (SMA), were relaxed by the increase. In basilar artery, the relaxation by the increase in [ $K^{+}$]$_{0}$ to from 1 to 3 mM was bigger than that by the increase from 6 to 12 mM. In contrast, in branches of SMA, the relaxation by the increase in [ $K^{+}$]$_{0}$ to from 6 to 12 mM is bigger than that by the increase from 1 to 3 mM. $Ba^2$$^{+}$ (30 $\mu$M) did not inhibit the relaxation by the increase in [ $K^{+}$]$_{0}$ from 1 to 3 mM but did inhibit the relaxation by the increase from 6 to 12 mM. In the mouse aorta without the endothelium or treated with $N^{G}$_nitro-L-arginine (30 $\mu$M), nitric oxide synthesis blocker, the increase in [ $K^{+}$]$_{0}$ from 6 to 12 mM did not change the magnitude of contraction induced either norepinephrine or prostaglandin $F_2$$_{\alpha}$. The increase in [ $K^{+}$]$_{0}$ up to 12 mM did not induce contraction of mouse aorta but the increase more than 12 mM induced contraction. In the mouse aorta, EDR was completely inhibited on increasing [ $K^{+}$]$_{0}$ from 6 to 12 mM. In cultured mouse aorta EC, [C $a^2$$^{+}$]$_{i}$ , was increased by acetylcholine or ATP application and the increased [C $a^2$$^{+}$]$_{i}$ , was reduced by the increase in [ $K^{+}$]$_{0}$ reversibly and concentration-dependently. In human umbilical vein EC, similar effect of extracellular $K^{+}$ was observed. Ouabain, a N $a^{+}$ - $K^{+}$ pump blocker, and N $i^2$$^{+}$, a N $a^{+}$ - $Ca^2$$^{+}$ exchanger blocker, reversed the inhibitory effect of extracellular $K^{+}$. In resistant arteries, the increase in [ $K^{+}$]$_{0}$ relaxes vascular smooth muscle and the underlying mechanisms differ according to the kinds of the arteries; $Ba^2$$^{+}$-insensitive mechanism in basilar artery and $Ba^2$$^{+}$ -sensitive one in branches of SMA. It also inhibits [C $a^2$$^{+}$]$_{i}$ , increase in EC and thereby EDR. The initial mechanism of the inhibition may be due to the activation of N $a^{+}$ - $K^{+}$pump. activation of N $a^{+}$ - $K^{+}$pump.p.p.p.