• KSBB Journal
• /
• v.8 no.3
• /
• pp.193-199
• /
• 1993

To find out the optimum conditions for indigo cell culture in air-lift bioreactor, effects of media composition including nutrients and precursors of the indigo colorants on the cell growth and characteristics of the cell growth under various cultural conditions were analyzed. Optimum cultural conditions were tested and the growth characteristics were analyzed in external and internal loop type air-lift bioreactors during 14-day culture. Better cell growth was obtained when the inoculum size was higher in the range of 0.5∼2.5% packed cell volume tested. In the sucrose concentration of 2 to 4%, the cell growth was better when the sucrose concentration was 4% (w/w) in both types of reactors. Sucrose was used up in the early stage of exponential phase of growth At the optimum concentration of a Precursor tryptophan at 1 U UW was 3.8 g/l in internal loop bioreactor, and 3.5 g/l in external one after 14 days of cultivation. Addition of indole showed negative effect on cell growth of suspension culture in air-lift biorector culture and cell mass of 2.5 g/l and 2.2 g/l were obtained in external and internal loop bioreactor, respectively. Selected inorganic nitrogen source potassium nitrate showed about 110% increase in cell growth than that of control. DCW was 16.34 g/l under optimum conditions during 14-day cultivation in internal loop bioreactor.

• Restorative Dentistry and Endodontics
• /
• v.33 no.4
• /
• pp.397-404
• /
• 2008

The purpose of this study was to evaluate the effects of MTAD, EDTA and sodium hypochlorite(NaOCl) as final irrigants on coronal leakage resistance to Enterococcus faecalis. Forty extracted human maxillary molars were used in this experiment. The teeth were randomly divided into positive control group (Group 1; n = 5), negative control group (Group 2; n = 5) and three experimental groups (n = 30). In Group 3 (n = 10), the root canals were irrigated with sodium hypochlorite. In Group 4 (n = 10) and 5 (n = 10), the root canals were irrigated with sodium hypochlorite and rinsed with EDTA and MTAD, respectively. The teeth in each group were cleaned and shaped to #40 profile with .04 taper, and obturated with gutta-percha and AH-26 root canal sealer. The coronal portion of each tooth was placed in contact with inoculum of Enterococcus faecalis in Brain Heart Infusion (BHI) culture media. Each root tip was placed in a vial containing sterile culture media. The vials were placed in anaerobic chamber and observed everyday for turbidity for 180 days. Statistical analysis was performed using Fisher's Exact Test. After 180 days, Group 3, 4, and 5 showed 7, 4 and 5 leaking samples respectively. The differences in leakage resistance were not statistically significant among Group 3, 4 and 5.

• Journal of Korean Society of Forest Science
• /
• v.101 no.1
• /
• pp.77-82
• /
• 2012

Sterilization of oak sawdust at $65^{\circ}C$ for Lentinula edodes bed cultivation can be efficient in sterilization facility cost, but its effect on the mushroom production is uncertain due to high contamination probability. The effective conditions for L. edodes hyphal growth in the low temperature sterilized oak sawdust were investigated with combinations of three sterilization temperatures ($65^{\circ}C$, $100^{\circ}C$ and $121^{\circ}C$) and four cultivation temperatures ($15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$). L. edodes inoculation density effect was also tested with 1 cm, 2 cm, and 4 cm distance in the sawdust (4%, 11% and 25% inoculation rate by surface area). L. edodes hyphal growth in the sawdust sterilized at $65^{\circ}C$ was as much as at those $100^{\circ}C$ and $121^{\circ}C$ when the fungus cultured below $25^{\circ}C$, but it was greatly reduced when cultured at $30^{\circ}C$. And the sawdust medium with 1cm distance inoculation density was fully occupied with L. edodes hyphae, but those with 2~4cm distance inoculation were contaminated by 4~33%. Therefore, we conclude that low temperature sterilized oak sawdust needs to be cultured under $25^{\circ}C$ after sufficient inoculation by 25% for successful bed cultivation of L. edodes.

• Research in Plant Disease
• /
• v.24 no.3
• /
• pp.193-201
• /
• 2018

Pectobacterium carotovorum subsp. carotovorum (Pcc) causes bacterial soft rot on a wide range of crops worldwide, especially in countries with warm and humid climates. This study was conducted to establish an efficient screening method for resistant cultivars of radish (Raphanus sativus) to bacterial soft rot. Resistance degrees of 60 commercial radish cultivars to the Pcc KACC 10421 isolate were investigated. For further study, six radish cultivars (Awooriwoldong, YR Championyeolmu, Jeonmuhumu, Bitgoeunyeolmu, Sunbongaltari, Housecheongok) showing different level of resistance to the bacterium were selected. The development of bacterial soft rot on the cultivars was tested according to several conditions such as incubation temperature, seedling stage of radish, inoculum concentration to develop the disease. On the basis of the results, we suggest that an efficient screening method for resistant radish to Pcc is to inoculate twenty-day-old seedlings with a bacterial suspension of Pcc at a concentration of $8{\times}10^5cfu/ml$ and then to cultivate the plants in a growth room at $25^{\circ}C$ and 80% RH with 12-hour light per day.

• The Korean Journal of Mycology
• /
• v.40 no.1
• /
• pp.49-53
• /
• 2012

Hot-water extracted natural media were made from raw materials for mycelial culture of Pleurotus eryngii. Poplar sawdust, wheat bran and rice bran were used as substrates for hot water extraction. The mixed substrates of poplar sawdust, wheat bran, and rice bran with 50 : 20 : 30 (v/v/v, PWR523) and 50 : 30 : 20 (v/v/v, PWR532) were optimal for mycelial growth of P. eryngii, respectively. The hot-water extracted natural media from PWR523 and PWR532 showed a rapid mycelial growth and spawn running compared to PDA. There was no significant difference in mushroom yield when the mycelium grown on the hot-water extracted natural media was used as the inoculum source for producing fruit body.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.110-116
• /
• 2013

This study was carried out to establish the simple mass-screening methods for resistant tomato to Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Root dip inoculation method has been used in many studies on the resistance of tomato to disease. On the other hand, in mass-screening for resistant tomato to Fusarium wilt, the inoculation method is time-consuming and laborious procedure. Disease development of two FOL isolates on two cultivars of tomato according to inoculation method including root dip, tip and scalpel methods were investigated. In compatible interaction, tomato seedlings of each cultivar inoculated by tip method showed the lower and more variable disease severities than by root dip method. Whereas the seedlings by scalpel method represented clear resistant and susceptible responses to Fusarium wilt as root dip method. The resistance degree of each cultivar inoculated with FOL isolates by scalpel method was hardly affected by the tested incubation temperature and inoculum concentration. On the basis of the results, we suggest scalpel inoculation method as an efficient mass-screening method for resistant of tomato cultivars to Fusarium wilt. Roots of tomato seedlings at two-leaf stage grown in plastic cell tray were injured with scalpel and then spore suspension (more than $1{\times}10^7\;conidia{\cdot}mL^{-1}$) of FOL was poured directly on the roots. The infected plants were cultivated in a growth room at $25-30^{\circ}C$ for 4 weeks with 12-hours light a day.

• Horticultural Science & Technology
• /
• v.19 no.1
• /
• pp.54-59
• /
• 2001

The objective of this research was to develop a screening system for selection of grape downy mildew (Plasmopara viticola)-resistant grape cultivars or seedlings under greenhouse condition. Inoculum concentrations ranging from $10^4$ to $10^5spores/mL$ for screening of resistance were evaluated and $5{\times}10^4spores/mL$ was optimum. Of the tested 14 grape cultivars, Campbell Early and Niagara were resistant to grape downy mildew, Sheridan and Cheongsoo were moderate resistant, while Kaiji, Red Queen and Ruby Okuyama were susceptible under both greenhouse and field conditions. Vitis vinifera grape cultivars were more susceptible to grape downy mildew than V. vinifera-labrusca hybrids and V. vinifera-labrusca-aestivalis hybrids. In V. vinifera-labrusca hybrids, tetraploid grape cultivars were more susceptible than diploid culivars. The evaluated results of grape downy mildew resistance under greenhouse condition were in accordance with those of field condition. Results of this study indicated that both greenhouse and field procedures could be used to screen grape cultivars and seedlings for downy mildew resistance.

• Korean journal of food and cookery science
• /
• v.21 no.2 s.86
• /
• pp.263-269
• /
• 2005

Citrus juice, a concentrate manufactured by the Jeju Provincial Corporation, was converted into vinegar orderly by alcohol and acetate fermentation. The juice with 6 folds dilution by distilled water was used as the sole nutrient source through out experiments. Diluted juice contained $12.96^{\circ}Brix$ of total sugar, $0.632\%$ of total acid and $20.23{\mu}g/m{\ell}$ of hesperidin. Naringin was not detected from the juice. Citrus wine having $5.6\~6.3\%$ alcohol was produced from diluted juice by 3 days of fermentation at $28^{\circ}C$. A kind of malomelo yeast CMY-28 was used for wine fermentation. The wine was succeedingly fermented for 8 days at $30^{\circ}C$ after inoculation of seed vinegar which contained active cells of acid producing bacteria CV1. Inoculum size of seed vinegar was controlled to $10\%$(v/v) of citrus wine. The wine converted into vinegar by the fermentation. Citrus vinegar, the final product of fermentation, was colored with very thin radish-yellow and transparent. It's acidity ranged between $5.8\~6.2\%$ as acetic acid. The vinegar got the best score by sensory test among several natural fruit vinegars. It was clear from the results that citrus vinegar in high quality could be produced from concentrated citrus juice, however fermentation conditions should be improved to reduce the amount of reducing alcohol.

• Korean Journal of Plant Resources
• /
• v.27 no.2
• /
• pp.194-201
• /
• 2014

This study was carried out to investigate the characteristics and infection effects of AMF with soil samples collected at some sites in Gyeonggi province, Korea. AMF spore and characteristics of infection structure in upland plant root were observed as wet sieving and staining method, growth of Capsicicum annum was compared between treatment and non treatment. AMF spores isolated from each soil sample were ellipse or circle type and the colors were soft yellow and white. The colonization rate of AMF with soil infection of Zea mays roots was 13.3~83.3%, the rate of infected soil collected from Z. mays was higher on average. When compared to the growth of C. Annum with control after infection on C. annum, it wasn't showing many differences in fresh weight, dry weight and height, but the yield of fruit of C. annuum showed double than the control group.

• Korean Journal of Soil Science and Fertilizer
• /
• v.39 no.6
• /
• pp.409-414
• /
• 2006

Sulfur-oxidizing bacteria were enumerated and isolated from a steady-state anaerobic master culture reactor (MCR) operated for over six months under a semi-continuous mode and nitrate-limiting conditions using thiosulfate as an electron donor. Most are Gram-negative bacteria, which have sizes up to 12 m. Strains AD1 and AD2 were isolated from the plate count agar (PCA), and strains BD1 and BD2 from the solid thiosulfate/nitrate medium. Based on the morphological, physiological, FAME and 16S rDNA sequence analyses, the two dominant strains, AD1 and AD2, were identified as Paracoccus denitrificans and Paracoccus versutus (formerly Thiobacillus versutus), respectively. From the physiological results, glucose was assimilated by both strains AD1 and AD2. Heterotrophic growth of strains AD1 and AD2 could be a more efficient way of obtaining a greater amount of biomass for use as an inoculum. Even though facultative autotrophic bacteria grow under heterotrophic conditions, autotrophic denitrification would not be reduced.