• Analytical Science and Technology
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• v.22 no.6
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• pp.449-457
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• 2009

Total PCBs (62 congeners) has been determined in the retailed foods by the isotopic dilution method and the exposure assessment has been performed. Put into a food sample $^{13}C$-labeled standard for recovery was added and then it was extracted, cleaned-up by multi-layer column chromatography and then analyzed by HRGC/MS. The average levels (ng/g) detected was 0.1 for rice, 1.8~3.4 for meats, 0.3~3.7 for milk and dairy products, 10.0 for egg and 0.8~34.4 for fishes. Distribution of total PCBs was in order of fishes (94.4%) > meats (2.3%) > eggs (1.7%) > milk and dairy products (1.3%) > rice (0.3%). The estimated daily intake(EDI) was 14 ng/kg bw/day. It was concluded that there was no health risk at all.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.1
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• pp.73-79
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• 1990

In order to study on the riboflavin content of common foods for Korean and the rates of destruction of riboflavin during cooking 26 kinds of the foods were selected and 3 kinds of menu were cooked by standardized method. For each food item and menu riboflavin content was measured by AOAC method. The experimental values of 13 kinds of food such as rice oak mushroom carrot squarsh tangle dried large anchovy apple(Fuji) dried laver ramyun pork soybean curd fried soybean curd and danmugi were almost consistent with food compo-sition values. Whereas those of 12 kinds of foods such as cabbage onion potato kimchi beef sausage dried medium anchovy hair tail soybean paste and egg were considerably different from food composition table values, up to now Alaskan pollack maize loaf bread hamburger bread etc have not been analyzed in food composition table, The rates of retention of riboflavin in menu 1, 2, and 3 cooked by standardized method were 24% 69% 46% respectively. The overally retention rate was in inverse proportion to the time of sunlight exposure during cooking.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.313-317
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• 2017

Paragonimiasis is a parasitic disease caused by Paragnonimus species. The primary site of infection is the lung, and extrapulmonary involvement is also reported. When infected with Paragonimus westermani, which is the dominant species in Korea, the central nervous system is frequently involved along with the liver, intestine, peritoneal cavity, retroperitoneum, and abdominal wall. Ectopic paragonimiasis raises diagnostic challenge since it is uncommon and may be confused with malignancy or other inflammatory diseases. Here, we report an ectopic paragonimiasis case initially presented with recurrent abdominal pain. The patient developed abdominal pain 3 times for the previous 3 years and the computed tomography (CT) of the abdomen revealed fluid collection with wall enhancement. Recurrent diverticulitis was initially suspected and part of the ascending colon was resected. However, the specimen showed intact colon wall without evidence of diverticulitis and multiple parasite eggs and granulomas were found instead. The size of about $70{\mu}m$, the presence of an operculum and relatively thick egg shell suggested eggs of Paragonimus species. With appropriate exposure history and a positive antibody test, the definitive diagnosis was made as peritoneal paragonimiasis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.135-139
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• 2002

In order to obtain the basic information for the seedling production of surf clam, Spisula sachalinensis, sperm motility and optimal method for fertilization were investigated. Sperm concentration of S. sachalinensis milt was$ 2.02{\times}10^{10}\;cell/mL$ and approximately $96.0\%$ of sperm showed forward movement after exposure to seawater. When sperm and eggs obtained by incision method were fertilized in 1 hour and 4 hours, respectively, high fertilization and hatching rate were achieved. The optimal sperm concentrations and egg density for fertilization and hatching were 10$\~$100 inds./egg and 100$\~$200 inds./mL sea water, respectively.

• Journal of Life Science
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• v.29 no.10
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• pp.1120-1125
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• 2019

The short-lived nematode Caenorhabditis elegans has been used as a model organism for many studies, including lifespan extension. To screen common seaweeds for natural anti-aging agents, the lifespan of C. elegans (N2 wild-type strain) was measured by its hatch rate, growth rate, survival rate, chemotaxis, brood size, and egg-laying time after exposure to nematode growth medium (NGM) containing seaweed extracts. Approximately 30 animals synchronized at the first larval stage were incubated until they reached their adult stages before laying their eggs and were transferred to fresh NGM every 3 days. We also identified the major active compound from the seaweed by gas chromatography-mass spectrometry and tested its optimal dose for longevity. Of 13 common seaweed species, an ethanol extract of the brown seaweed Hizikia fusiformis showed the greatest effect on hatching, growth, and survival rates. The lifespan of C. elegans was significantly expanded 1.54-fold and 1.23-fold in the presence of the ethanol extract (0.05 mg/ml) and the main active component, fucosterol (0.05 mg/ml), respectively. Exposure to the ethanol extract also increased chemotaxis 1.13-fold, decreased brood size 0.74-fold, and shortened egg-laying time 0.96-fold. These results suggest that the aquaculturable H. fusiformis may be a promising source of a diet supplement to support health care.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.79-85
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• 2007

From the surveys of 2005 and 2006 in Korea, Trissolicus nigripedius was found in four locations, i.e., Andong, Miryang, Namhae, and Suwon, and one of the major egg parasitoids of Dolycoris baccarum. T. nigripedius was also found to parasitize two other soybean bugs, Riptortus clavatus and Piezodous hybneri, from the field collection in 2005. Host acceptance behaviors of T. nigripedius consisting of drumming, oviposition, and marking were observed and compared on five species of soybean bugs. T. nigripedius showed the complete host acceptance behaviors on the eggs of D. baccarum, P. hybneri, and Halyomorpha halys. But T. nigripedius emerged only from the eggs of D. baccarum (96%) and P. hybneri (75%) after 24 hours of exposure. T. nigripedius did not mark on the eggs of R. clavatus and Nezara antennata during the observation of behavior, hence no egg deposition was made. However, T. nigripedius parasitized 20% and killed 30% of the eggs of R. clavatus when 24 hours were given for parasitization. T. nigripedius would be a potential biological control agent of D. baccarum and P. hybneri with ability of giving additional mortality on R. clavatus in soybean field.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.144-154
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• 2007

The acute and chronic toxicity of ambient and effluent water discharged to Lake Shihwa were investigated by using Vibrio fischeri, Daphnia magna and Oryzias latipes. Physicochemical characteristics including biochemical oxygen demand (BOD) and nine heavy metals in a total of 15 water samples were evaluated and were satisfied with relevant Korean Water Quality Standards (KWQS) except for Hg in one sample. Acute toxicity was observed in five samples collected from three sampling locations. When impacts on reproduction and growth after chronic exposure were evaluated with D. magna, all the samples showed significant chronic effects. Reproduction appeared relatively more sensitive endpoint. In 21 days chronic tests on O. latipes, survival, mean egg number per female per day, hatching success rate and time to hatch were affected by increasing sample concentration. The organ-level changes such as gonadosomatic index (GSI), and hepatosomatic index (HSI), and molecular biomarker of vitellogenin (Vtg) induction that evaluated with O. latipes increased as exposure concentrations increased. It is noteworthy that the samples that did not exceed the KWQS resulted in acute and chronic toxicities. The results suggested that numeric criteria based on physicochemical parameters may not be protective of aquatic ecosystem. Acute and chronic toxicity tests with organisms representing different trophic groups should be supplemented in order to provide adequate level of environmental protection.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.91-99
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• 1986

This experiment was undertaken to examine the effects of HIS treatment on the motility and acrosome reaction of frozen bovine spermatozoa and to test their abilities to interact with zona-free hamster eggs in vitro. Also, in vitro results were compared with those of bull's fertility in AI. The frozen semen from four Holstein bulls were exposed to HIS-DM for 5 minutes after thawing and then preincubated for 60 minutes in DM prior to insemination. The hamster eggs were mounted, fixed and stained 6 hours after exposure to boving spermatozoa and examined under a phase-contrast microscope. 1. The sperm motility expressed as a mobility index dro, pp.d significantly from 60-75 to 12-24 after exposure to HIS-DM, but increased in 32 to 41 at insemination. Bull C showed a low motility index than those of the orher bulls. The percentage of acrosome reaction by staining procedure were increased by HIS-DM treatment but did not change during 7 hours incubation period in DM. 2. The overall percentage of hamster eggs interacting with bull spermatozoa was 56.3%, 58.3%, 66.6% and 70.0%, respectively. Although there was no significant difference among bulls in the penetration rate of spermatozoa into hamster eggs, high proportions of eggs interacted with spermatozoa from Bull C and D than those from Bull A and B. 3. The conception rates (60-90 day RP) resulting from AI were 62.5%, 67.5% and 70.9% for Bull A, B and C, respectively. These results were in good agreement with the invitro results that the proportions of bull sperm-egg interction were greater for Bull C than for Bull A and B.

• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.35-41
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• 2006

Vitellogenin (Vtg), a phospholipoglycoprotein precursor of egg yolk is synthesized and secreted from the liver in response to estrogens in female fish. Vtg is normally undetectable in the blood of male fish, but can be induced by exposure to chemicals possessing estrogenic activity. Thus, the presence of Vtg in blood of male fish can serve as a useful biomarker for assessing previous exposure to estrogenic compounds. In the present study, Vtg was abnormally expressed in Rhynchocypris oxycephalus using estradiol benzoate ($E_2$). As the result, it was found that the level of Vtg in blood from R. oxycephalus was increased by treated quantity of $E_2$ with dose-effect manner. Monoclonal antibodies were generated against Vtg of R. oxycephalus. The hybridoma were screened with an enzyme immunoassay for the production of specific anti-Vtg antibodies. Five positive cell lines with a high specificity were selected. Monoclonal antibodies against vtg of R. oxycephalus that was developed in this study, may be a useful bio-indicator for the detection of estrogenic contamination in the aquatic ecosystem.

• Environmental Analysis Health and Toxicology
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• v.25 no.3
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• pp.241-251
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• 2010

Crucian carp (Carassius auratus) has been used as the sentinel species for POPs (Persistent Organic Pollutants) monitoring in aquatic environment. However, there is little information for dioxin toxicity and especially, early life stage toxicity in crucian carp have been never carried out. In this study, we investigated several toxic effects for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in fertilized egg obtained by natural fertilization from crucian carp. The embryos at 3 h post-fertilization (hpf) were treated with 0.039, 0.156, 0.625, and 2.5 (${\mu}g/L$) TCDD by waterborne exposure for 60 minutes and changed with fresh water 2 times per day. Fertilized eggs started hatching at 51 hpf and TCDD exposed embryo showed decrease of hatching rate in a dose-dependent manner at 75 hpf. Pericardial edema was continuously observed in larvae exposed to TCDD from hatching start time (51 hpf), followed by the onset of mortality. In addition, AhR-related gene, CYP1A was clearly increased by TCDD in a dose dependent manner. These results indicated that fertilized eggs obtained from crucian carp have the TCDD related gene regulation and a distinct TCDD developmental toxicity syndrome by TCDD exposure. Therefore, we suggested that early life stage test in crucian carp could be used as test methods on dioxins toxicity.