• Journal of Marine Life Science
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• v.5 no.2
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• pp.35-42
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• 2020

17β-estradiol (E₂) is a natural hormone secreted by ovary, and continuously discharged from household and livestock wastewater into aquatic environment. Due to its strong estrogenic activity, it has adverse effects on development and reproduction in crustacean as an endocrine disrupting chemical. Although ecdysteroid signaling pathway play a key role in development in crustacean, little information on transcriptional modulation of ecdysteroid-related genes in response to E₂ is available in small crustacean. Here, we investigated the acute toxicity of E₂ to obtain 24-h LC_x values in the brackish water flea Diaphanosoma celebensis. Time-dependent expression patterns of seven ecdysteroid pathway - related genes (CYP314a1, EcRA, EcRB, USP, ERR, Vtg, VtgR) were further examined using quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR). As results, 24-h LC₅₀ and LC₁₀ values were 9.581 mg/l and 4.842 mg/l, respectively. The mRNA expression of CYP314a1, EcRA, USP, VtgR was significantly up-regulated at 12 or 24 h after exposure to E₂. These findings indicate that E₂ can affect their molting and reproduction by modulating the expression of ecdysteroid pathway - related in D. celebensis. This study will be useful for better understanding of molecular mode of action of endocrine disrupting chemicals on molting process in small crustacean.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.274-277
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• 2007

In this study, liquid crystal(LC) aligning capabilities for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method were investigated. Also, the control of pretilt angles and thermal stabilities of the nematic liquid crystal(NLC) treated on $SiO_x$ thin film were investigated. A high pretilt angle of about $86.5^{\circ}$ was obtained, and also the suitable pretilt angle of the NLC on the $SiO_x$ thin film at $10{\sim}50nm$ thickness with e-beam evaporation can be achieved. The uniform LC alignment and good thermal stabilities on the $SiO_x$ thin film surfaces with electron beam evaporation can be achieved. It is considered that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.34-34
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• 2020

희귀식물(LC)인 낙지다리(Penthorum chinense Pursh.)는 '수택란', '차근채'로 불리며 약용으로 사용되어 왔으나, 최근 하천개수 및 습지매립 등으로 자생지가 파괴되어 개체수가 급감하고 있다. 따라서 본 연구는 낙지다리의 종 보존 및 활용을 위하여 종자의 최적발아조건을 확인하고자 수행하였다. 종자는 2017년 국립백두대간수목원에서 수집되어 연구에 사용되기 전까지 건조 상태(15℃, 15% RH)로 시드뱅크(-20℃, 40% RH)에 저장하고 있었다. 종자의 최적발아조건을 확인하기 위하여, 항온과 변온 66조건에서 발아율과 최종발아율의 50%가 발아하는데 소요되는 일 수(T₅₀)를 조사하였으며, 생리적 휴면 타파를 위해서 GA₃(20~1000 mg·L^-1) 처리 후 발아율과 T₅₀을 조사하였다. 그리고 GA₃ 처리에 따른 유묘 생장에 대한 GA₃의 영향을 확인하기 위하여 종자 치상 30일 후 유근·아 생장에 대한 영향을 조사하였다. 낙지다리 종자는 항온보다 변온에서 발아율 증가와 T₅₀ 감소를 보였다. 특히 낮/밤의 온도 차가 11~25℃일 때, 85%이상의 발아율을 보였고, 그 이상의 온도차이가 나면 발아율은 감소하는 경향을 보였다. T₅₀은 온도차가 증가할수록 감소하여, 발아가 균일하며 빨라지는 것을 확인 할 수 있었다. 또한 GA₃ 처리시 생리적 휴면 타파가 진행되어 발아율(79.8%~100%)과 발아속도가 증가(T₅₀ 감소)함을 확인하였으나, GA₃ 100mg·L^-1 이상의 농도에서는 무처리(21.2m)에 비하여 유근의 길이 생장을 0.11~6.88mm로 지연시켰다.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.374-379
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• 2005

Sublethal dose effect of imidacloprid on green peach aphid (Myzus persicae) was investigated. Nymphs of green peach aphid newly produced were counted on 4 days after sub-lethal dose treatment of imidacloprid. Numbers of nymph were not significantly different between $LC_1$ treatment and untreated control. Their numbers of nymph were 8.8 and 12.7 at $LC_1$ and untreated control, respectively. When they were tented at $LC_{10}$, $LC_{30}$ and $LC_{50}$. their numbers of newly produced nymph were 6.0, 5.1 and 3.9 and reduction rates were 52.7%, 59.8% and 69.3% at each treatment compare to untreated control. Reduction rates of newly laid nymph were proportional to the concentrations of imidacloprid treated. Repellent effect of aphid to imidacloprid was bigger in dipping than in watering method. Secretion amount had negative correlation with imidacloprid concentration in dipping method and suppression of secretion went up to 96%. In watering method, amount of secretion did not show any difference between insecticide concentration, but suppression, compared to untreated control, was over 97%.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.197-203
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• 2023

Callus cultivation is a method for producing a large amount of tissue of a plant in the laboratory, regardless of the environment. Lycoris chejuensis, a plant species native to jeju island, is a member of the Lycoris family has been used as a traditional medicine for the treatment of diverse diseases. In this study, we evaluated anti-inflammatory effect of biorenovated Lycoris chejuensis callus (LCB) in lipopolysaccharide (LPS)-induced RAW264.7 cells. As a result, LCB was less toxic to the cells in the concentration range of 25, 50, and 100 ㎍/mL as shown by the improved viability of LCB treated cells than compared to Lycoris chejuensis callus (LC) treatment. In addition, LCB inhibited the generation of NO and prostaglandin E₂ through the suppression of inducible nitric oxide synthase and cyclooxygenase-2 protein expression. LCB also attenuated the expression of interleukin-1β, interleukin-6 and tumor necrosis factor-α induced by LPS. The results suggest that LCB has anti-inflammatory activity on the LPS-induced inflammatory response and may be suitable for the development of potent functional cosmetic material.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.129-138
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• 2022

Crucian carp, Carassius carassius (Weight 42.4 ± 9.0 g, Length 15.0 ± 1.0 cm) were exposed to waterborne zinc at 0, 5, 10, 20, 40 and 80 mg Zn²⁺/l for 96 hours. The lethal concentration 50 (LC₅₀) at 96 hours of crucian carp, C. carassius exposed to waterborne zinc was 51.58 mg Zn²⁺/l. In hematological parameters, the RBC count was significantly decreased in the concentration of 40 mg Zn²⁺/l at 48 hours, whereas the hematocrit was significantly increased by zinc exposure. The MCV (mean corpuscular volume) (µl) and MCH (mean corpuscular hemoglobin) (pg) were significantly increased in the concentration of 40 mg Zn²⁺/l at 48 hours. The plasma components such as calcium, magnesium, glucose, cholesterol, total protein and ALT (Alanine aminotransminase) were significantly changed by zinc exposure. The results of this study suggest that the zinc exposure to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as toxicity.

• Journal of Life Science
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• v.26 no.2
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• pp.181-189
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• 2016

The aim of this study was to identify the effects of dithiopyr (DTP), a herbicide, on behavior in zebrafish. The toxicity of DTP has rarely been investigated in fish. In the present study, zebrafish were exposed to different concentrations of DTP in the range of 10-20 μM for 48 h in a test container, in order to measure the value of median lethal concentrations (LC₅₀). Behavioral experiments were performed, including the novel tank test (NTT) and the open field test (OFT), to assess stress responses or locomotion. After exposure to the DTP solution at a sublethal concentration of 2.5–10 μM for 6 min, the behavior of the zebrafish was observed for 6 min. In the acute toxicity test, the LC₅₀ value of DTP showed as 14.49 μM in the zebrafish. The NTT showed that the duration of immobility and the velocity were significantly increased by exposure at a concentration of 5 μM of DTP, compared with a control group (p<0.05). However, compared with the control group, DTP significantly decreased the distance moved and the frequency at the top of the tank, and significantly increased the turn angle and duration at the bottom, in a concentration-dependent manner (p<0.05). In addition, in the OFT, exposure to DTP significantly decreased the distance moved and velocity compared with the control group (p<0.05). Exposure to DTP also significantly increased the duration of immobility, the turn angle, and the meandering movement, in a concentration-dependent manner (p<0.05). Further, exposure to DTP at a low concentration elevated whole-body cortisol levels in the zebrafish. The results of this study thus suggest that DTP induces a toxic response and negative effects on behavior and the endocrine system in zebrafish.

• Journal of Ginseng Research
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• v.46 no.4
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• pp.536-542
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• 2022

Background: In aged skin, reactive oxygen species (ROS) induces degradation of the extracellular matrix (ECM), leading to visible aging signs. Collagens in the ECM are cleaved by matrix metalloproteinases (MMPs). Syringaresinol (SYR), isolated from Panax ginseng berry, has various physiological activities, including anti-inflammatory action. However, the anti-aging effects of SYR via antioxidant and autophagy regulation have not been elucidated. Methods: The preventive effect of SYR on skin aging was investigated in human HaCaT keratinocytes in the presence of H₂O₂, and the keratinocyte cells were treated with SYR (0-200 ㎍/mL). mRNA and protein levels of MMP-2 and -9 were determined by real-time PCR and Western blotting, respectively. Radical scavenging activity was researched by 2,2 diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. LC3B level was assessed by Western blotting and confocal microscopy. Results: SYR significantly reduced gene expression and protein levels of MMP-9 and -2 in both H₂O₂-treated and untreated HaCaT cells. SYR did not show cytotoxicity to HaCaT cells. SYR exhibited DPPH and ABTS radical scavenging activities with an EC₅₀ value of 10.77 and 10.35 ㎍/mL, respectively. SYR elevated total levels of endogenous and exogenous LC3B in H₂O₂-stimulated HaCaT cells. 3-Methyladenine (3-MA), an autophagy inhibitor, counteracted the inhibitory effect of SYR on MMP-2 expression. Conclusion: SYR showed antioxidant activity and up-regulated autophagy activity in H₂O₂-stimulated HaCaT cells, lowering the expression of MMP-2 and MMP-9 associated with skin aging. Our results suggest that SYR has potential value as a cosmetic additive for prevention of skin aging.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.221-229
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• 2022

This study was aimed to investigate spatial and vertical characteristics of greenhouse environments according to the location of the environmental sensors, and to investigate the correlations between temperature, light intensity, and carbon dioxide (CO₂) concentration according to the type of greenhouse. Temperature, relative humidity (RH), CO₂, and light sensors were installed in the four-different vertical positions of the whole canopy as well as ground and roof space at the five spatial locations of the Venlo greenhouse. Also, correlations between temperature, light intensity, and CO₂ concentration in Venlo and semi-closed greenhouses were analyzed using the Curve Expert Professional program. The deviations among the spatial locations were larger in the CO₂ concentration than other environmental factors in the Venlo greenhouse. The average CO₂ concentration ranged from 465 to 761 µmol·mol^-1 with the highest value (646 µmol·mol^-1) at the Middle End (4ME) close to the main pipe (50Ø) of the liquefied CO₂ gas supply and lowest (436 µmol·mol^-1) at the Left Middle (5LM). The deviation among the vertical positions was greater in temperature and relative humidity than other environments. The time zone with the largest deviation in average temperature was 2 p.m. with the highest temperature (26.51℃) at the Upper Air (UA) and the lowest temperature (25.62℃) at the Lower Canopy (LC). The time zone with the largest deviation in average RH was 1 p.m. with the highest RH (76.90%) at the LC and the lowest RH (71.74%) at the UA. The highest average CO₂ concentration at each hour was Roof Air (RF) and Ground (GD). The coefficient of correlations between temperature, light intensity, and CO₂ concentration were 0.07 for semi-closed greenhouse and 0.66 for Venlo greenhouse. All the results indicate that while the CO₂ concentration in the greenhouse needs to be analyzed in the spatial locations, temperature and humidity needs to be analyzed in the vertical positions of canopy. The target CO₂ fertilization concentration for the semi-closed greenhouse with low ventilation rate should be different from that of general greenhouses.

• Journal of Life Science
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• v.30 no.4
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• pp.321-330
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• 2020

The aim of this study was to investigate the effect of copper (II) chloride (CuCl₂) on zebrafish. Zebrafish were exposed to various CuCl₂ concentrations and subjected to different exposure times to determine the median lethal concentration (LC₅₀) values. To evaluate stress responses, we measured whole-body cortisol levels and behavioral parameters using the open field test (OFT) or the novel tank test (NTT). The zebrafish were exposed to CuCl₂ solution at concentrations of 1.5-150 ㎍/l or a vehicle for 1 hr before behavioral tests or sample collection for whole-body cortisol. The LC₅₀ values were 30.3, 25.3, and 14.8 ㎍/l at 24, 48, and 96 hr, respectively. The NTT showed that mobility, velocity, and distance covered were significantly lower in zebrafish exposed to CuCl₂ than in the control group (p<0.05), while the turn angle was significantly higher in zebrafish exposed to a CuCl₂ concentration of 150 ㎍/l than in the control group (p<0.05). The OFT also showed that mobility, velocity, and distance covered were significantly lower and the turn angle and meandering were significantly higher in zebrafish exposed to all concentrations of CuCl₂ than in the control group (p<0.05). The whole-body cortisol levels were significantly higher in zebrafish exposed to CuCl₂ than in the control group (p<0.05). These results suggest that exposure to lethal CuCl₂ concentrations induces an intense toxic and stress response in zebrafish, causing behavioral changes and increasing whole-body cortisol levels.