• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1017-1023
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• 2010

This study investigated the effect of surfactants (nonionic surfactant (Tween 20), biosurfactant) on enhancing transport of bacteria (Bacillus subtilis ATCC 6633) in geological materials. Column experiments were performed under various surfactant conditions with columns packed with quartz sand (particle size distribution: 0.5~2.0 mm, mean diameter: 1.0 mm). Bacterial mass recovery, sticking efficiency, and other parameters were quantified from breakthrough curves. Results indicate that bacterial attachment to sand surfaces increased considerably in the presence of mineral salt medium (MSM), especially at the inlet, which was due to the increase of ionic strength by MSM. It was observed that bacterial transport in sand columns was enhanced in the presence of surfactant. Results also show that simultaneous injection of both surfactant and MSM or pre-injection of surfactant was more effective in bacterial transport enhancement than after-injection of surfactant. This study suggests that transport of bacteria in geological materials could be influenced by surfactants and their injection methods.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.69-82
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• 1994

This study was conducted to investigate the physiological characteristics and to isolate plasmid DNA of R. japonicum strains. The results obtained were as follows; Strains S117, S118, 005, 011 and DY-1 were slow-growers and showed alkaline reaction, whereas strains S110, S111, S114, S116, S120 and 010 were fast-growers and produced acid reaction in YEM broth. All the fast- and slow-growing R. japonicum showed gram negative and formed mucous white colony on agar plate. After 7 days, the colonies of the fast-growers were between 2.0 and 4.0mm in diameter, whereas those of slow-growers were approximately between 0.5 and 1.5mm. The fast-growers were uniformly sensitive to the pH of 4.5 and tolerant of the pH of 9.5, whereas the reverse was found for the slow-growers. All the fast-growers were able to grow in the presence of 2% NaCl however the slow-growers were not grown. All the microorganisms grew rapidly in simple mineral salt medium containing as the sole source of carbon. Starch was rarely utilized. All the fast-growers utilized sucrose. The slow-growing R. japonicum strains examined usually contained 1 to 3 plasmid DNA ranging between 15Kb and 250 Kb, whereas the fast-growing R. japonicum strains contained 1 to 3 plasmid DNA ranging from 20 Kb to 250Kb.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.95-100
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• 2004

The main objectives of the study were to investigate cultural characteristics of Phellinus linteus. The optimum culture media for mycelial growth of P. linteus were MYA (malt yeast agar) and SMS (soybean powder malt Sucrose). Similarly, optimum temperature and pH were $30^{\circ}C$ and 6.0, respectively. Malt extract (2%, v/v) and yeast extract (0.2%, v/v) were optimum carbon and nitrogen sources. Similarly, 0.1% $KH_2PO_4$ was optimum mineral salt. Highest mycelial growth was observed when C/N ratio was 10 : 1. Optimum inoculum amount for flask culture was $5{\sim}6$ mycelial discs (6 mm diameter) per 100 ml of liquid medium, Highest mycelial dry weight was obtained when cultured in 100 ml liquid medium in 300 ml shaking flask after 20 days of shaking culture, For mass liquid culture (8 l), flask culture was homogenized and used as an inoculum. Optimum culture period and aeration rate for 8l fermentation culture were 12 days and 2.0 vvm, respectively.

• Journal of Mushroom
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• v.21 no.1
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• pp.15-21
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• 2023

Volvariella bombycinais an edible mushroom commercially cultivated in Korea and other countries. In this study, the culture characteristics and optimal growth conditions of milky mushroom strains were determined. The growth temperature and pH range of V. bombycinawas extensively investigated between 15 and 35℃ and pH 3-11. For efficient cultivation, 20 types of nutrient sources were selected, specifically, 21 carbon sources, 6 organic nitrogen sources, 7 inorganic nitrogen sources, 13 amino acids, 9 organic acids, and 13 inorganic salts. The impact of each of the selected nutrition sources and their concentration on growth was investigated. The optimum temperature and pH were determined to be 30℃ and pH 8.0, respectively. The optimum concentration of medium elements required for mycelial growth of V. bombycinawas determined to be as follows: carbon source, 0.7% Soluble starch; organic nitrogen source, 0.7% Soytone; inorganic nitrogen source, 1.0% (NH₄)₂C₄H₄O₆; amino acid, 0.1% cysteine; organic acid, 0.07% lactic acid; and inorganic salt, 0.07 mM CaCl₂.

• Korean Journal of Animal Reproduction
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• v.14 no.4
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• pp.263-271
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• 1990

This study was carried out to investigate the factors affecting maturation in vitro of follicular oocytes in Korean Native Cattle. The bovine ovaries were obtained at a slaughter house and the follicular oocytes were recovered by aspirating the follicular fluid from the visible follicles of 3~6mm. The bovine oocytes were matured in vitro in TCM-199 containing FCS and hormones. The effects of TCM-199 salt type, number of oocytes per drop, incubation time and co-culture with granulosa cells on maturation of oocytes, were investigated. The results obtained are summarized as follows. 1. The maturation rates of follicular oocytes cultured for 22, 25 and 28 hours in Hank's TCM-199 or Earle's TCM-199 were 59.3, 59.6, 80% and 80.0, 90.0, 93.7%, respectively. The maturation rate of follicular oocytes in Earle's TCM-199 was faster and higher than in Hank's TCM-199(P<0.05). 2. The maturation rates of oocytes were 54.5, 62.5 and 62.0% when cultured the oocytes number 10, 20 and 40 per 200${mu}ell$ drop for 18 hours. 3. The maturation of follicular oocytes in the Korean Native Cattle was induced at 14 hours culture, by giving the maturation rate of 90.0% after 20 hours. 4. The maturation rates were 63.3% and 66.7%, respectigely when the oocytes were co-cultured with granulosa cells from medium-size follicles used immediately after recovery in the presence or absence of hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$). When the oocytes were co-cultured with granulosa cells from medium-size follicles cultured for 3 days, the maturation rates were 20.8% and 76.2%, respectively(P<0.05). 5. The maturation rate were 88.0% and 70.0%, respectively when the oocytes were co-cultured with granulosa cells from large-size follicles used immediately after recovery in the presence or absence of hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$)(P<0.05). When the hormones added(0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH and 1$\mu\textrm{g}$/ml estradiol 17-$\beta$)(P<0.05). When the oocytes were co-cultred with granulosa cells from large-size follicles cultured for 3 days, the maturation rates were 41.2% and 73.3%, respectively(P<0.05).

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.319-329
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• 1990

Effects of atrial natriuretic peptide (ANP) on blood pressure, plasma lenin activity, aldosterone and renal excretion were compared in conscious spontaneously hypertensive rats (SHR) and normotensive Wistar rats fed low, medium or high sodium diet (2, 10, 25 mmol NaCl/100g diet) for 6 weeks. ANP infusion (380 ng/kg/min for 20 min) produced reductions in blood pressure, plasma renin activity, and aldosterone level, but marked increases in hematocrit, urine flow, and excretions of sodium and potassium. The low sodium group showed a significantly enhanced aldosterone lowering effect of ANP than the high sodium group. However, three salt groups showed no difference in effects of ANP on blood pressure, plasma renin activity, hematocrit and diuresis. Natriuretic response to ANP was significantly greater in the high salt-than in the low sait-SHR, but was not different between the Wistar salt groups. There were strain differences in effects of ANP: SHR showed greater responses of blood pressure and natriuresis than Wistar rats. Above results indicate that aldosterone-lowering and natriuretic effects of ANP were modifed by different dietary sodium intakes. However, blood pressure- and renin-lowering, or diuretic effects of ANP were not affected by dietary sodium intakes. The mechanisms whereby dietary sodium intakes alter the effects of ANP in the pathogenesis of hypertension are not clear.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.1072-1077
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• 2010

Plant diseases including gray mold caused by Botrytis cinerea are often reduced when calcium compounds are used as alternative materials in paprika. However, much less information is available about the effects of calcium compounds on controlling of $B.$ $cinerea$. Seven calcium compounds such as calcium sulfate dihydrate, calcium chloride, calcium nitrate, calcium oxide, calcium hydroxide, calcium carbonate, and calcium hydride were evaluated for their effectiveness against $B.$ $cinerea$ on potato dextrose agar medium. The pH of selected calcium compounds was higher (pH 8.2-10) than that of the control (pH 6.6). Calcium carbonate, calcium oxide, calcium hydride, and calcium hydroxide among seven calcium compounds were more effectively inhibited the growth of $B.$ $cinerea$ than other calcium compounds. In the case of spraying the spore suspension on paprika applied with the selected four calcium compounds and supplied with the selected calcium supplements in a hydroponic culture system, the paprika treated with calcium compounds showed less severity of disease than those untreated plants. On the basis of our results, we propose that the suppressive effects of calcium compounds on $B.$ $cinerea$ in paprika resulted from the supply of calcium and a certain degree of salt stress.

• Journal of fish pathology
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• v.36 no.2
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• pp.263-275
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• 2023

Chum salmon (Oncorhynchus keta) is a species which returns to Korea for spawning and was produced as seed production at the Fisheries Resources Agency located in Uljin-gun, Gyeongsangbuk-do to preserve the species. However, farmed chum salmon showed symptoms of bacterial infection. Therefore, in this study, bacteria were isolated to identify the causative agent from chum salmon in October 2021. The isolated bacteria were identified based on the sequences of 16S rDNA, rpoD (RNA polymerase sigma factor σ⁷⁰), and vapA (A-layer) genes. Also, salinity-growth curve, biochemical characterization, antibiotic susceptibility test, and pathogenicity analysis were performed in four strains. As a result, four isolated strains were identified as Aeromonas salmonicida subsp. salmonicida. Additionally, the bacterial strains showed a decrease in growth as the salt concentration increased in the medium. All of the isolated strains exhibited γ-hemolysis, and the same biochemical properties. In the antimicrobial susceptibility test, all strains showed an inhibition zone of 40 to 44 mm for oxolinic acid, flumequine, and florfenicol. Pathogenic factors were assessed by RT-PCR at the mRNA level, and found that the four strains expresses the outer membrane ring of T3SS (ascV), inner membrane ring of T3SS (ascC), vapA, enterotoxin (act), and lipase (lip) genes which are well known to significantly contribute to the pathogenicity of A. salmonicida. The results of this study can be used as basic data to prevent A. salmonicida subsp. salmonicida occurring in sea-chum salmon in the future.