• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.197-206
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• 1990

Various conditions of cultures were performed to investigate the role of tight junctions formed between adjacent MDCK cells on the entry of Toxoplasma. When MDCK cells were cocultured with excess number of Toxoplasma at the seeding density of 1×105, 3×105, and 5×105 cells/ml for 4 days, the number of intracellular parasites decreased rapidly as the host cells reached saturation density, i.e., the formation of tight junctions. When the concentration of calcium in the media (1.8 mM in general) was shifted to $5{\mu}M$ that resulted in the elimination of tight junction, the penetration of Toxoplasma increased about 2-fold(p<0.05) in the saturated culture, while that of non-saturated culture decreased by half. Trypsin-EDTA which was treated to conquer the tight junctions of saturated culture favored the entry of Toxoplasma about 2.5-fold(P<0.05) compared to the non-treated, while that of non- saturated culture decreased to about one fifth. It was suggested that the tight junctions of epithelial cells play a role as a barrier for the entry of Toxoplasma and Toxoplasma penetrate into hoot cells through membrane structure-specific, i.e., certain kind of receptors present on the basolateral rather than apical surface of MDCK cells.

• Development and Reproduction
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• v.2 no.1
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• pp.29-37
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• 1998

To investigate the role of oviductal environment in early mammalian development, we examined the effects of bovine oviductal fluid (bOF) on the development of mouse 2-cell embryos in vitro. All of the embryos cultured in medium containing 5% or more of bOF underwent degeneration after 48 hr, whereas only 5% of embryos cultured in the absence of bOF degenerated. When bOF was heated at 65 \circ C for 30 min and then added to the culture medium, the embryotoxic effect of bOF was not removed at all such that none of the embryos remained alive after 48 hr. However, when bOF heated at 90 \circ C for 30 min was added to the culture, nearly most (95%) of embryos was alive. Similarly, pretreatment of bOF with 0.1% chymotrypsin for 1 hr or overnight following heating at 65 \circ C resulted in the development of 95.5% of mouse 2-cell embryos to early blastula after 48 hr culture in the presence of treated bOF. Interestingly addition of an anti-oxidant removed the evbryotoxic effect of bOF so that 91.0% of 2-cell embryos developed to morulae or blastulae in the presence of both 5% bOF and 10 mM of glutathione (GSH) after 48 hr culture. Neither oxidized form of GSH (GSSG) nor other antioxidants, however, could support the embryonic development in the presence of bOF. From these results, it is suggested that bOF contains a protein-like factor(s) which becomes embryotoxic by exposing in vitro, probably via oxidation reaction.

• KSBB Journal
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• v.14 no.3
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• pp.303-308
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• 1999

An in vitro culture method for entomopathogenic nematode Steinernema glaseri was developed. A symbiotic bacterium was isolated from Steinernema glaseri and identified as Xenorhabdus nematophilus. Phase variation that differed in some biochemical characteristics of symbiotic bacterium was observed. Entomopathogenic nematodes carried only phase I bacterium in their guts. Phase I bacterium could be converted into phase II form in in vitro culture medium consisting of 5% yeast extract, 0.5% NaCl, 0.05% $K_2HPO_4$, $0.02% MgSO_4$.$7H_2O$. The optimum temperature for bacterial growth was $28^{\circ}C$. The pH of the culture medium increased up to 9.0-9.5 during the exponential growth period of the culture, regardless of initial pH 6-7. Various culture media such as chicken offal, dog food, bovine liver, peanut, and so on were tested for in vitro culture of the nematodes. The best medium for Steinernema glaseri production was obtained from concentrated homogenate of bovine liver and the nematode growth was highest at 80% bovine liver. In the co-culture of entomopathogenic nematode with its symbiont, the growth rate of nematodes was 2 times faster than that without its symbiont and the nematode concentration reached about $5.5\times10^4$/mL within 15 days.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.71-73
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• 2001

In this study, we could improve transmission efficiency of germline chimeras by transfer of gonadal PGCs (gPGCs) cultured in vitro. Of hatched recipient chicks, 301 chickens (141 males and 160 females) were brought up to sexual maturity and these WLs (KOC) were mated with KOCs for testcross, resulting in 27 germline chimeras (15 males and 12 females) identified by black feather color of their progenies. The production efficiency of germline chimera production of experimental groups was observed (P=0.6831). The average transmission efficiency of proven germline chimeras was 0.6 ∼56.5% (15.0% on average). The transmission efficiency of experimental group which were transferred 10-days cultured gPGCs without Ficoll treatment was highest (49.7%) and that of experimental stock which transferred non-cultured gPGCs with Ficoll treatment was lowest (0.6%). The duration of in vitro culture before transferring was significantly important for the high efficiency of germline transmission. Transferring 10-days cultured gPGCs made the transmission efficiency higher rather than transferring non-cultured and 5-days cultured gPGCs, 50 times and 10 times, respectively (p<0.0001). However, Ficoll treatment for increasing the population ratio of gPGCs negatively affected the transmission efficiency and the effects of sexuality and the reciprocal interaction between treatments showed no significant differences. These findings demonstrated that the crucial factors for improving the germline transmission were the duration of in vitro culture prior to transfer. Thus, we developed the complete system for production of germline chimera using cultured gPGCs with highly improved efficiency and this system would be useful for genetic manipulation and obtaining the transgenic aves.

• Food Science and Preservation
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• v.23 no.6
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• pp.765-771
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• 2016

Omija-cheong, concentrated extracts from sugar-treated Omija fruit (Schisandra chinensis Baillon), is produced by traditional manner in Korea. The quality characteristics of Omija-cheong processed at low temperature with a pilot-scale were investigated to optimize the incubation time. With increasing incubation time in processing Omija-cheong, the pH level of Omija-cheong remained constant, while titratable acidity and organic acids increased. Fresh Omija fruits contained citric, malic and succinic acids, most of which were extracted into concentrated extracts after 37 days of incubation and reached to the stable concentration after 47 days of incubation. Titratable acidity in Omija-cheong gradually increased from 1.18% to 2.71%, and also was correlated with total concentration of organic acids. About 80% of supplemented sucrose for manufacturing Omija-cheong was converted into glucose and fructose until 68 days of incubation, and the composition of free sugars was maintained to be stable up to 138 days of incubation. The contents of total flavonoids and phenolic compounds in Omija-cheong were 24.1 mg-GAE/L and 1,635 mg-QE/L at 57 days of incubation, which were more than 9 and 5 times higher than those in Omija fruits, respectively. From the quality characteristics in processing Omija-cheong by low-temperature incubation, more than 60 days of incubation is required for the constant quality and value-added beverage.

• Clean Technology
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• v.4 no.1
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• pp.45-59
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• 1998

Continuous immobilized-cell culture was carried out for the production of kasugamycin, a secondary metabolite by a filamentous bacteria, Streptomyces kasugaensis, with an intention of reducing waste generation. A sporulation medium was developed for production of bulk amounts of spores, and the spores were entrapped into celite biosupports for immobilization. It was possible to effectively keep the immobilized-cells inside the reactor during the continuous culture by an efficient immobilized cell separator of decantor type on the outlet of the fermentor. Using this continuous immobilized-cell fermentor system, we investigated the effects of feed substrate and phosphate concentrations on kasugamycin production and chemical oxygen demand(COD). Comparing with the conventional suspended-cell batch culture, the kasugamycin productivity was observed to increase by 2.5 times, whereas COD per unit kasugamycin production decreased by 2.3 times in the continuous immobilized-cell culture. Based on these results, the continuous immobilized-cell system was considered to be a cleaner bioprocess than the conventional batch suspended-cell system.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.54-59
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• 2004

$\beta$-Glucan has been efficiently produced with higher yield by the optimization of liquid cultivation conditions. The optimal composition of medium for batch culture was 5% (w/v) of glucose as a carbon source, 0.5% (w/v) of yeast and 0.5% (w/v) of malt extract as a nitrogen source, 0.1% (w/v) of $KH_2PO_4$ and 0.05% (w/v) $MgSO_4{\cdot}7H_2O$, which had been the base medium for determination of other conditions. The set-up conditions are pH 5.0, $28^{\circ}C$, 1 vvm for aeration and 300 rpm for agitation. In order to minimize the inhibition effect of glucose on the initial growth of mycelia and to maximize the production of extracellular $\beta$-glucan, we have reduced the initial glucose feed to 4% and added 2nd feed at the point of 70 hr from the initial feed. The 2nd feed was composed of glucose 3%, yeast extract 0.1 % and malt extract 0.1 %. It improved the $\beta$-glucan yield upto 5.2 g/L in comparison with 2.8 g/L resulted from batch cultivation. Moreover, the serial treatment of a cell wall lytic enzyme and bromelain to the mycelia was effective for extraction of the cell wall bound $\beta$-glucan. The yield of $\beta$-glucan extraction by the enzyme treatment was 3.5 g/L, which was almost 4 times higher than that by hot-water extraction.

• Journal of Plant Biology
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• v.38 no.2
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• pp.211-215
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• 1995

병풀(Centella asiatica)의 엽병 조직절편에서 유도된 배발생 캘러스로부터 체세포배 발생에 의하여 소식물체의 재분화를 이루었다. 엽병 조직절편을 1mg/L 2,4-D와 1mg/L kinetin이 조합 처리된 MS 기본배지에 치상하여 85%의 효율로 배발생 캘러스를 유도할 수 있었으며 이와 같은 배발생 캘러스를 5mg/L NAA와 1mg/L kinetin이 첨가된 배지로 옮겼을 때 체세포배의 형성은 87%까지 이루어졌다. 체세포배는 기본배지의 농도를 절반으로 줄이고 0.2 mg/L NAA와 0.2 mg/L kinetin이 첨가된 배지조건에서 기관분화를 거쳐 소식물체로 재분화되었다.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.46-46
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• 2002

본 연구는 돼지의 미성숙 난포란을 체외에서 성숙, 수정시킨 후, 생산된 체외수정란을 NCSU 23 체외배양액에 항산화제 (NAC, ebselen 및 glutathione) 와 glutathione 합성억제제인 BSO의 첨가가 돼지 체외 수정란의 체외 발육에 미치는 영향을 검토하였다. Glutathione 합성 억제제인 BSO가 돼지 수정란의 체외 발육에 미치는 영향을 검토한 결과, 0, 1.0 및 5.0mM의 BSO 을 첨가하여 상실배기 이상 발육된 체외 발육 성적은 각각 35.9, 15.7 및 8.4%로서 BSO 첨가구가 대조구에 비해 통계적으로 유의하게 낮은 체외배율성적을 나타냈으며 (P＜0.05), NAC 1.0mM, ebselen 10μM 및 glutathione 100μM 과 BSO 1.0 mM 을 각각 첨가하여 체외 배양을 실시한 경우, 상실배 이상 발육된 체외 발육율은 40.5, 44.2, 36.0 및 10.9%로서 항산화제 첨가구가 BSO 첨가구보다 통계적으로 유의하게 높은 체외 발육 성적을 나타냈다 (P＜0.05). 모든 처리구에서 체외 수정 후 생산된 배반포기 수정란의 세포수에는 차이가 인정되지 않았다. (중략)

• KSBB Journal
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• v.7 no.3
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• pp.222-228
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• 1992

The effects of sucrose solution on cell growth and berberine production were studied in Thalictrum rugosum cell cultures. Application of sucrose solution without any other components enhanced berberine accumulation significantly in spite of slower cell growth. At high sucrose concentration, cells became very compact and fourfold increase in specific berberine content was achieved. Optimum concentration of sucrose in plain water to maximize the productivity was found to be 8%. Time course experiment in 8% sucrose solution showed that more than 5 days were required to utilize the advantage of this system efficiently. Addition of vitamins, growth regulators, and inorganic salts into the solution was not effective in increasing berberine productivity.