• The Korean Journal of Malacology
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• v.30 no.3
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• pp.189-196
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• 2014

A significant production decrease has been witnessed for the Pacific oysters, Crassostrea gigas farmed in the western coastal waters of Korea, presumably by the loss of physiological viability. We evaluated the viability in terms of health indicators, the condition indices and hemocyte apoptosis rates of the oysters inhabiting two representative farming sites, Incheon and Taean each with different environmental variables. In our monthly measurements for the whole year 2013, the indicators were location specific. The condition indices of Incheon were highly variable, 1.67-8.58%, while those of Taean were less, 2.28-5.57%. The condition indices decreased during the spawning seasons, July and September in common. The two oysters exhibited also differed in the apoptotic activities of hemocyte, highly active, 4.03-30.15% for Incheon oysters and less active, 2.87-17.48% for Taean oysters. One thing we could identify was the two measurements were adverse during the critical seasons of spawning, reminiscent of being a useful tool for a health indicator for the oysters. Similar trend was also observed in the time when change in temperature was extreme. The findings in this study are highly indicative of health indicators for the oyster aquaculture.

• Environmental Engineering Research
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• v.10 no.5
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• pp.205-212
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• 2005

The study was conducted to investigate the removal of heavy metals by using Hydroxyapatite(HAp) made from waste oyster shells and wastewater with high concentration of phosphorus. The maximum calcium concentration for the production of HAp in this study was released up to 361 mg/L at pH of 3 by elution experiments. When the pH was at adjusted 6, the maximum calcium released concentration was 41 mg/L. During the elution experiment, most of the calcium was released within 60 minutes. This reaction occurred at both pH levels of 3 and 6. The result of the XRD analysis for the HAp product used in this study shows the main constituent was HAp, as well as OCP. The pH was 8.6. As the temperature increased, the main constituent did not vary, however its structure was crystallized. When the pH was maintained at 3, the removal efficiency decreased as the heavy metal concentration increased. The order of removal efficiency was as follows: $Fe^{2+}$(92%), $Pb^{2+}$(92%) > $Cu^{2+}$(20%) > $Cd^{2+}$(0%). Most of these products were dissolved and did not produce sludge in the course of heavy metals removal. As the heavy metal concentration increased at pH of 6, the removal efficiency increased. The removal efficiencies in all heavy metals were over 80%. From the analysis of the sludge after reaction with heavy metals, the HAp was detected and the OCP peak was not observed. Moreover, lead ion was observed at the peaks of lead-Apatite and lead oxidant. In the case of cadmium, copper and iron ions, hydroxide forms of each ion were also detected.

• Journal of Mushroom
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• v.4 no.2
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• pp.53-56
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• 2006

The enormous production of spores by the fruitbodies in the cultivation of oyster mushrooms (Pleurotus ostreatus) is develop an allergy with symptoms similar to an "extrinsic allergic alveolitis (EEA)". the sporeless strain would noy only benefit health of mushroom workers but also reduce the risk of viral infections on the mushroom farms. For the development of a sporeless strain of P. ostreatus we used strain ASI 2069. This non-commercial strain is completely nonsporulating. We have recovered both nuclear types of strain ASI 2069 as monokaryons (hereafter referred to as neohaplonts) by protoplasting the mycelium. Crosses between neohaplonts and SSI's(single spore isolates) obtained from a sporulating commercial strain ASI 2180 yielded fruitbodies that isolated 128 strains. 13 excellent strains are selected from 30 bred strains by quality of fruitbodies and spore number. Among 13 excellent strains, G192 strain is chose finally to high yield and sporelessness.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.3
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• pp.5-14
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• 2022

Trichoderma is known as pathogen caused serious green mold disease on commercial production. T. pleuroti and T. pleuroticola were common species in various mushroom media. Many strains of T. pleuroti, known as aggressive species causing major economic losses in Korea, showed benomyl resistance. Accurate identification and detection of Trichoderma species associated with oyster mushrooms is very important for disease control. We developed species-specific primers for T. pleuroticola, T. pleuroti, T. harzianum, and T. atroviride based on species-specific fragments isolated from amplified fragment length polymorphism analysis. PCR products corresponding to the predicted fragment of 500bp, 230bp, 180bp, and 410bp were amplified from T. pleuroticola, T. pleuroti, T. harzianum, and T. atroviride, respectively. Multiplex PCR assay using species-specific primers quickly and accurately identified and detected T. pleuroti from mushroom media in which various species co-exist. Our results can be useful for the effective control of mushroom disease.

• Mycobiology
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• v.42 no.2
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• pp.193-197
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• 2014

Laccase activity of Pleurotus ostreatus is significantly increased by the addition of apple pomace. Among various conditions, the best concentration of apple pomace and cultivation time for the production of laccase by P. ostreatus was 2.5% and 9 days, respectively. Reverse transcription polymerase chain reaction analyses of laccase isoenzyme genes, including pox1, pox3, pox4, poxc, poxa3, and poxa1b, revealed a clear effect of apple pomace on transcription induction. Our findings reveal that the use of apple pomace can be a model for the valuable addition of similar wastes and for the development of a solid-state fermenter and commercial production of oyster mushroom P. ostreatus.

• Mycobiology
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• v.41 no.4
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• pp.252-255
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• 2013

Fungal pathogens have caused severe damage to the commercial production of Pleurotus eryngii, the king oyster mushroom, by reducing production yield, causing deterioration of commercial value, and shortening shelf-life. Four strains of pathogenic fungi, including Trichoderma koningiopsis DC3, Phomopsis sp. MP4, Mucor circinelloides MP5, and Cladosporium bruhnei MP6, were isolated from the bottle culture of diseased P. eryngii. A species-specific primer set was designed for each fungus from the ITS1-5.8S rDNA-ITS2 sequences. PCR using the ITS primer set yielded a unique DNA band for each fungus without any cross-reaction, proving the validity of our method in detection of mushroom fungal pathogens.

• KSBB Journal
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• v.13 no.4
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• pp.343-351
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• 1998

About 75 strains which utilize cholesterol as sole carbon and energy source were isolated from 10 samples of Kimchi and 18 samples of fermented fish food (2 Ojingo-jeots, salt-fermented squid ; 5 Changran-jeots, salt-fermented pollack tripe ; 5 Myungran-jeots, salt-fermented Alaska pollack roe ; 3 Gajami-sikhae-jeots, fermented flat fish ; 2 Gul-jeots, salt-fermented oyster ; a Juneo-jeots, salt-fermented shad). Among them tested, the 3T6-5Mj strain isolated from Changran-jeot showed the highest activity on cholesterol degradation. The optimal composition of medium for the producing cholesterol degradation enzyme by 3T6-5Mj strain was 1.0 g/L NH4NO3, 1.0 g/L K2HPO4, 0.1 g/L MgSO4.7H2O, 1.0 g/L FeSO4.7H2O, 1 g/L NaCl, 5 g/L Trypton, 1 g/L Cholesterol, and 5 g/L Maltose at 30$^{\circ}C$, pH 7.5, and the enzyme production reached a maximum level at 140 hours of cultivation.

• Journal of Mushroom
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• v.20 no.4
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• pp.193-198
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• 2022

The biological efficiencies of promising Pleurotus spp. were evaluated. Pleurotus ostreatus, Pleurotus tuberregium,and Pleurotus sajor-cajuwere investigated at temperatures of 22℃, 20℃, and 18℃ to determine their ability to adapt to temperatures that are likely to be found in subtropical regions. The experiment was conducted using a substrate comprising Popular sawdust 60% + cotton seed 20% + beet pulp 20% under a relative humidity of 65%. The results indicated that there were significant differences in terms of biological efficiency between the species: P. tuber regium 128.84% at 22℃, P. ostreatus 108.41% at 22℃, and P. sajor-caju is 80% at 20℃. The common temperatures at which all species showed the highest biological efficiencies were 22℃ and 20℃. Therefore, the production of the evaluated species was equal to or surpassed biological efficiencies reported in tropical environments, thereby demonstrating a potential opportunity to adapt to tropical environments without compromising quality standards.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.542-549
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• 2017

To evaluate bacteriological and toxicological safety, the hygienic indicator bacterium and paralytic and diarrhetic shellfish toxins in the shellfish produced in the Kamakman Area from 2012 to 2016 were investigated. Fecal coliforms and E. coli of all 194 oyster samples tested did not exceed 230 MPN/100 g. The geometric mean of the fecal coliform analyzed with the oyster samples of harvesting period was 19.6 MPN/100 g, which was more stable than the non-harvesting period (26.5 MPN/100 g). For the toxicological evaluation of the Kamakman Area, 77 oyster samples and 350 mussel samples as an indicator were analyzed. Paralytic shellfish toxins were detected very low in the range of $40{\sim}46{\mu}g$/100 g in 13 mussel samples during late April and early June, but not in oyster samples. Diarrhetic shellfish toxin was detected in 2 of 180 samples, but it was found to be below the regulation value (0.16 mg OA equ./kg). Based on the bacteriological studies, it was confirmed that the shellfish produced in Kamakman area meets the standard of shellfish hygiene of the Food Sanitation Act and meets the Grade A of the shellfish production area of EU. As the results of the paralytic and diarrhetic shellfish toxin evaluation, it was confirmed that the Kamakman Area is also toxicologically safe for shellfish production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1940-1948
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• 2013

This study is conducted to investigate the antioxidative effect of oyster hydrolysates in the serum and liver of SD-rats through the determination of lipid content, production of free radicals and antioxidant enzyme activities. Two different hydrolysates, Protamex-treated and Neutrase-treated hydrolysate with the cross-linking of protein by transglutaminase (TGPN group) and without (PN group), were fed for 6 weeks. TGPN hydrolysate in serum and liver significantly decreased the total cholesterol in the range of 26.1% to 28.9%, and triglyceride in the liver of up to 6.3%. Superoxide radical in the serum and lipid peroxide radical in the liver were significantly decreased in SD-rats fed 200 mg TGPN hydrolysate. Superoxide dismutase activity was significantly decreased in the liver of SD-rats. These results indicate that TGPN hydrolysate could scavenge the superoxide and hydroxyl radicals, and reduce the superoxide dismutase and catalase activities. The TGPN is also protected the oxidation of protein by the free radicals.