• Journal of Life Science
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• v.12 no.6
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• pp.708-714
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• 2002

A new leaf blight was found on the perilla leaves at the major perilla-cultivating areas such as Kangdong in Busan and Miryang in Kyungnam province. Symptoms of the disease initially appeared on the edge of perilla leaves showing black necrosis and drying, and the infected leaves were finally fell down. The SD1 isolate showing strong pathogenicity and forming abundant conidial spores on the diseased lesions was isolated. Among the tested media, mycelial growth was abundant on PDA (Potato Dextrose Agar) medium at $25^{\circ}C$ under dark condition, but conidial formation was greater on V8A (V-8 juice A8ar) medium than that on PDA medium. Optimal temperatures for mycelial growth and conidial formation on PDA medium were respectively $25^{\circ}C$ and 3$0^{\circ}C$. The rate of conidial germination and the elongation of germ tube were more effective in 10% tomato juice than those in PDB (Potato Dextrose Broth) and sterile water. In 10% tomato juice, the rate of conidial germination and the length of germ tube were 100% after incubation for 24k and 535.2${\mu}{\textrm}{m}$ after incubation for 36hr, respectively. According to the result of pathogenicity, it revealed that conidial suspention with 10% tomato juice was the most effective for pathogenicity test showing as 100% of disease incidence, and the symptoms caused by artificial inoculum were same as those of naturally infected perilla. In this study, the SD1 isolate according to the results of morphological characteristics, the incubation characteristics and pathogenicity was firstly identified A. alternata, and named as leaf blight of perilla.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.772-780
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• 2013

The aim of this study was to investigate the effect of season and location on activities of enzyme produced by psychrotrophic bacteria isolated from raw milk located in Kyunggi region of South Korea. Agar diffusion and colorimetric methods were used for the lipase and protease activities of psychrotrophic bacteria. Intensities of dark blue and transparent ring around colony were compared for activity measurement. Nutrient agar with 1% skim milk added was employed for measuing protease activity. 14 strains of Arthrobacter russicus with lipase activity and 19 strains of Chryserobacterium shigense with protease activities were found to be present. It was found that Acinetobacter genomospecies 10 (match %: 99.90) isolated from B region in fall was the most lipolytic species, whereas Serratia liquefaciens (match %: 99.39) isolated from the same region in spring was the most proteolytic species. Growth curve of Acinetobacte and Serratia liquefaciens was a typical sigmoidal form. Lipase activity increased with incubation time, but its activity began to drop at stationary to motality phase. Optimum condition for incubation time, pH and temperature for extracellular lipase from Acinetobacter genomospecies 10 (match %: 99.90) was 12 h, 8.5, and $45^{\circ}C$, respectively. Extracellular protease from Serratia liquefaciens (match %:99.39) had the same optimum incubation time and pH as extracellular lipase, but optimum temperature was $35^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.4 no.4
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• pp.259-264
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• 1972

Oxidative changes of the Ramyon lipids were studied under three experimental storage conditions. Ramyon was 1) exposed to fluorescent light irradiation at $25^{\circ}C$, 2) incubated in the dark at $40^{\circ}C$ and 3) irradiated with ultra-violet light at $25^{\circ}C$. In the study, changes in acid value, peroxide value, carbonyl value, TBA number, fatty acid composition and iodine value were determined with the lipids extracted from the Ramyon samples in intervals for a period of 20 weeks. Acid value, peroxide value, and TBA number of the samples under fluorescent light irradiation and $40^{\circ}C$ incubation increased slightly during storage, while a sharp increase of those values were noticed with the samples of ultra-violet light irradiation. Especially, the TBA number of the Ramyon lipid under ultra-violet light irradiation markedly increased within 10 weeks and then decreased. With this change in TBA number, however, the bound form of malonaldehyde increased gradually. During the storage under $40^{\circ}C$ incubation, and ultra·violet irradiation for 10 weeks, the content of linoleic and linolenic acids decreased, while palmitic and stearic acids increased. However, only small changes were noticed in iodine value of the samples. On the other hand, oxidative rancid odor appeared at the end of 16 weeks storage under fluorescent light irradiation and $40^{\circ}C$ incubation, while it took only 4 weeks with the sample stored under ultra-violet irradiation.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.306-312
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• 2017

Changes in the cell growth and lipid accumulation of marine microalga Dunaliella tertiolecta were investigated in response to the combination of different stress factors including the variation of iron supply as a primary stress factor and different options in light irradiation and $CO_2$ supply as a secondary stress factor. High or limited Fe conditions could act as a stress for lipid synthesis. As a secondary stress factor, non-$CO_2$ condition was good for lipid accumulation, but the overall cell growth was sacrificed significantly after a long-time cultivation. Dark condition as a secondary stress factor also favored lipid accumulation and the extent of cell density reduction at the early period in the dark was small compared to other stress conditions. The two-stage cultivation strategy was necessary to maximize lipid production because tendencies of the cell growth and lipid content were not identical under the chosen stress condition. The first stage was for preparing a high cell density under the normal growth-favoring condition and the second stage was the stress condition to induce lipid accumulation in a short time. The short-term (12 h) incubation under the 5X Fe (3.25 mg/L) and dark conditions resulted in the best lipid productivity of 1.44 g/L/d providing 2 g/L inoculum at the second stage.

• Journal of Mushroom
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• v.7 no.3
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• pp.115-121
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• 2009

Recently sawdust cultivation of Shiitake mushroom (Lentinula edodes ) is getting increased because log cultivation is getting difficult to get oak logs. It is important to make mycelia browning on the substrate surface in sawdust cultivation. This browned surface plays an important role like as artificial bark of the oak log, which protects the other pests and suppresses water evaporation in the substrate. The period for mycelia browning is so long that the sawdust cultivation of Shiitake mushroom can not spread well into the mushroom farms. In this article we would like to discuss about the effect of environmental condition to the mycelial browning during sawdust bag cultivation for the To reduce the period required for browning of substrates, sawdust substrates was illuminated light with difference intensity. One hundred Lux light illumination was needed for producing normal yield of fruit body but fruit body yield was low and abnormally shaped fruit body was produced when cultured under the dark condition of incubation. Illumination over 200lux is necessary for the successful browning of substrates during incubation. Optimum incubation temperature for browning of substrates and fruiting was $25^{\circ}C$. The treatment of cotton plug with different size to identify the effect of aeration on the browning of substrates and fruiting showed rapid mycelial growth and reduced the periods for browning as the size of cotton plug was bigger. However, yield of fruit body was the highest at 16mm diameter cotton plug as compared to 20mm of that. $CO_2$ content in vessel of substrates was low as the size of cotton plug was bigger during incubation. $CO_2$ content during incubation of substrate was highest in periods between 8 week and 14 week after inoculation of shiitake when substrate was changed color into brown. $C_2H_4$ content in vessel with substrates was highest at 8mm diameter cotton plug and it was increased by order of 12, 16, 20, 0, 4 mm diameter cotton plug during substrate incubation. Sawdust substrate was soaked in cold water for different time to identify soaking effect of sawdust substrate on fruit body yield and activities of enzymes in these substrates were investigated. The fruit body yield was increased up to 40% by soaking substrates in comparison with unsoaked substrates. The soaked substrates showed 165, 175g/1,000ml at treatment of 4 and 15 hours, respectively. Cellulose activities in soaked substrates were not changed with soaking time, but activities of laccase, lignin degradation enzyme, were drastically increased up to 4 times in comparison with unsoaked substrates.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.216-221
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• 2001

Dieback of pine branches or twigs with brown needles occurs most commonly on Pinus species after severe winter in Korea. In this study, Cenangium ferruginosum was isolated from infected stems, branches, and twigs of Pinus koraiensis (C1), P. densiflora (C2), and P. thunbergii (C3). Morphological and cultural characteristics of the isolates were than compared. There were no significant differences in the morphological characteristics of conidia and ascospores produced by the three isolates. However, cultural differences were observed among the isolates. Optimum temperatures for mycelial growth of C1, C2, and C3 were 15, 20, and $20^{\circ}$, respectively. C1 produced a few conidia and no ascospores, while C2 and C3 produced abundant ascospores and conidia. While optimum temperatures for mycelial growth ranged from 15 to $20^{\circ}$, mycelial growth was also relatively good at lower temperatures of 5-$10^{\circ}$. Conidiomata and conidia were produced on MSA (malt extract soya peptone agar) after 25-30 days of incubation in the dark at $15^{\circ}$. Apothecia were produced by altering culture condition from 15 to $20^{\circ}$, and incubating for 35-60 more days. Optimum temperature for ascospore and conidium germination was $20^{\circ}$. RAPD analysis revealed that there was high similarity of 0.78 between C2 and C3, and low similarity of 0.31 between C2 or C3 and C1.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.77-80
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• 2002

A simple method for sporangial formation of the rice downy mildew pathogen, Sclerophthora macrospora, on infected leaf tissues was developed to facilitate diagnosis of the disease. Freshly infected young leaves showing whitish to yellowish small spots were selected and cut into small pieces about 2-3 cm in length. About 10-20 pieces were surface sterilized in a 100 ml Duran bottle with 40 ml of 70% ethanol by vigorous shaking for 30 seconds. After washing three times with distilled water, the leaf cuts were submerged in 10 ml of Millipore-filtered paddy water and incubated at $20^{\circ}C$ in the dark. After 8-10 h of incubation, the bottle was vigorously agitated on a vortex mixer, Aliquot amount of the suspension, 0.1-1.0 m1, was spread on a slide glass and examined under a light microscope at 50 or 100x magnification. It was found that light and 1% NaClO strongly inhibit sporangial formation of S. macrospora. Meanwhile, the use of freshly infected young loaves and washing with 70% ethanol stimulated sporangial formation of the fungus on rice leaves.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.438-443
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• 2016

The in vitro propagation of the commercially important Phalaeonopsis hybrid 'Little gem' was achieved by culturing the apical part and axillary buds excised from flower stalks. The explants were cultured on 5 different basal media: $3.0{\cdot}L^{-1}$ Hyponex and $4.0{\cdot}L^{-1}$ peptone ($H_3P_4$) and Murashige & Skoog (MS) media were shown to be suitable for shoot regeneration. The MS medium supplemented with $5.0mg{\cdot}L^{-1}$ 6-benzylaminopurine (BA) was found to be more efficient for shoot regeneration. However, the number of shoots induced by axillary buds was higher than that induced by the apical part. Incubation of the apical part under darkness for one week, as well as of the explants in the same medium with activated charcoal (AC) $0.5g{\cdot}L^{-1}$ promoted shoot regeneration and shoot growth; similar growth was not observed with axillary buds.

• KSBB Journal
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• v.24 no.1
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• pp.59-64
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• 2009

The callus formation from inferior leaf of Aloe saponaria was induced in M & S medium supplemented with 10-30 ${\mu}M$ NAA (${\alpha}$-naphthalene acetic acid) and 3-7 ${\mu}M$ kinetin under incubation in the dark at $25^{\circ}C$ for 6 weeks. The hot water extract ($100^{\circ}C$, 24 hrs) from cultured callus was obtained and the components analysis for the extract were examined to determine the callus can synthesized the bioactive component such as Aloe polysaccharide. The freeze dried extract contained the sugar of 53.2%, protein of 7.3%, ash of 18.5% and water of 21% (w/w). Two fractions (Fr-I and Fr-II) were obtained by Sepharose CL-4B gel permeation chromatography and Fr-I, major fraction was further purified with dialysis. From sugar analysis by TLC and GC, the purified Fr-I fraction consisted of glucose (77.6%), galactose (17.7%), mannose (4.7%, w/w) and uronic acid (trace). The molecular weight of purified Fr-I fraction determined by GPC was about 110 kDa.

• Journal of Hydrogen and New Energy
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• v.15 no.2
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• pp.166-174
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• 2004

Purple non-sulfur bacteria, Rhodobacter sphaeroides KD131 grew to reach the maximum cell concentration in 45 hrs of incubation in the synthetic media containing (NH4)2SO4, L-aspartic acid and succinic acid as the carbon and nitrogen sources, respectively, at 30oC under 8 klux irradiance using halogen lamp. The strain produced hydrogen from the middle of the logarithmic growth phase and continued until the cell growth leveled out. The strain grew and produced hydrogen under the irradiance of 3-30 klux, but cell growth was inhibited over 100 klux. In addition, anaerobic/light culture condition was better than the aerobic/dark on the hydrogen production. Among various photo-bioreactors examined, the flat-vertical reactor manufactured using clear acrylic plastic material showed the best hydrogen production rate at the given culture condition.