• KSBB Journal
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• v.13 no.1
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• pp.83-89
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• 1998

Using a cellulose macroporous microcarrier, HeLa cells were cultivated in 100mL spinner flask(Bellco Co., USA) and confluent cell laden microcarriers were subcultured by bead-to-bead cell transfer method. In macroporous mcirocarrier-HeLa system viable suspended cells played an important role in bead-to-bead cell transfer and that could be increased by use of RPMI-1640, a calcium-ion-reduced-media and high speed agitation. Successful bead-to-bead cell transfers were performed continuously three time in spinner flask. We applied this technique to produce recombinant Vaccinia virus which express $\beta$-galactosidase. Recombinant protein yield of bead-to-bead transferred culture was comparable to conventional microcarrier cultures that were inoculated by cells detached from T-flask. Although trypsinization is a useful method for subculturing microcarriers in some cases, that process adds quality control problem and handling steps to large scale cell production. There fore, bead-to-bead cell transfer technique offers another convenient and efficient scale-up method for continuous microcarrier cultures.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.19-24
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• 2007

Callus induction using leaf of purple sweetpotato (PSP) was decreased when subcultured. So we selected habituated callus in MS medium supplemented with $1{\mu}M\;2,4-D$ (2,4-dichlorophenoxyacetic acid) after 6 months of cultures (without subculture). It grew faster and easier than any other callus. It was able to proliferate in MS hormone free solid and liquid medium without any growth regulators and subculture limits. During subculture in liquid medium, a purple mottled spot formed in one of habituated cell aggregates without any treatment. This purple cell aggregates were carefully separated from habituated cell aggregates, and then subcultured by selecting purple cell aggregates for more than 2 years to be isolated. The color value of the pigment extracted of culture was 1.0 mg/mL, which was close to that of a pigment extracted from storage root, which was 1.5 mg/mL. This purple cell aggregates could therefore be used for the industrial mass production of anthocyanin.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.59-64
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• 1995

Effects of salicylic acid (SA) on anthocyanin synthesis in cell suspension cultures of grapes (Vitis vinifera L.) were investigated. tow concentrations (0.1 to 1$\mu$M) of SA did not affect the cell growth and anthocyanin accumulation whereas high concentrations (5 to 10$\mu$M ) of SA inhibited cell growth with increasement of anthocyanin synthesis. Five micromoles of SA promoted anthocyanin accumulation 4 folds compared to control cells. When SA was treated on the different culture times (0 to 7day), the highest pigment accumulation was obtained at the cells of second day. A low productivity of anthocyanin under continuous dark incubation was also recovered by adding SA which mimicked light irradiation effect These results suggest that SA is one of essential agents in anthocyanin biosynthesis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.3_4
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• pp.92-96
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• 1973

This examination was carried out to evaluate the sanitary quality of slices of raw fish being served in the restaurants. Twenty five kinds of slices of raw fish collected from various restaurants in Busan Korea were examined during the period from March to May in 1971. As the evaluation factors of sanitary quality, the contents of sanitary indicative bacteria such as coliform group, fecal coliform, feral streptococci and enterococci and plate counts were determined. The results obtained are as in below: 1. The numbers of fecal streptococci and enterococci MPN were much greater than those of coliform group and fecal coliform. 2. The median value of coliform group MPN was 3,300 per 100 grams of the sample examined and those of enterococci was 5,400. The median value of plate counts was $1.8\times10^5$ per gram. 3. Fifty-two percent of the samples examined were exceeded fecal coliform MPN 930 per 100 grams. 4. As a sanitary indicative bacteria fecal coliform MPN was more reasonable than enterococci 5. The grade of restaurants was not correlated with the bacterial quality of the foods served. 6. No correlation between the numbers of sanitary indicative bacteria ana plate counts was observed.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.4
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• pp.311-319
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• 2009

Objective: Human embryonic stem cells (hESCs) have the capacity to differentiate into all of the cell types and therefore hold promise for cell therapeutic applications. In order to utilize this important potential of hESCs, enhancement of currently used technologies for handling and manipulating the cells is required. The cryopreservation of hESC colonies was successfully performed using the vitrification and slow freezing-rapid thawing method. However, most of the hESC colonies were showed extremely spontaneous differentiation after freezing and thawing. In this study, we were performed to rapidly collect of early passage hESCs, which was thawed and had high rate of spontaneously differentiation of SNUhES11 cell line. Methods: Four days after plating, partially spontaneously differentiated parts of hESC colony were cut off using finely drawn-out dissecting pipette, which is mechanical separation method. Results: After separating of spontaneously differentiated cells, we observed that removed parts were recovered by undifferentiated cells. Furthermore, mechanical separation method was more efficient for hESCs expansion after thawing when we repeated this method. The recovery rate after removing differentiated parts of hESC colonies were 55.0%, 74.5%, and 71.1% when we have applied this method to three passages. Conclusion: Mechanical separation method is highly effective for rapidly collecting and large volumes of undifferentiated cells after thawing of cryopreserved early passage hESCs.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.158-165
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• 1999

Purpose : To investigate the percentage of colonies wi1h16or more cells distribution of human skin fibroblast according to in vitro aging, and to evaluate the relationship between percentage of colonies with 10 or more cells and in vivo donor age in human skin fibroblast culture. Material and Method : C1, C2, C3a, and C3b human skin fibroblast samples from three breast cancer patients were used as subjects. The C1, C2, and C3a donor were 44, 54, and 55 years old, respectively. C3a and C3b cells were isolated from the same person. Single cell suspension of skin fibroblasts was prepared with primary explant technique. One hundred cells are plated into 100m1 tissue culture flask and cultured for two weeks. The colony size was defined as colonies with 16 or more cells. The cultured cell was stained with crystal violet, and number of cells in each colony was determined with stereo microscope at $\times$10 magnification. Passage number of C1, C2, C3a and C3b skin fibroblast were 12th, 17th, and 14th, respectively. Results : Percentage of colonies with 16 or more cells of skin fibroblast samples decreased with increasing in vitro passage number. In contrast, cumulative population doublings of skin fibroblast sample increased with increasing in vitro passage number. Percentage of colonies with 16 or more cells also decreased with increasing population doublings in human skin fibroblast culture. There was strong correlation with percentage of colonies with 16 or more cells and population doublings En C3a skin fibroblast sampie. At the same point of population doublings, the percentage of colonies with 16 or more cells of the young C1 donor was higher level than the old C3a donor. Conclusion : The population doublings increased with increasing in vitro passage number but percentage of colonies with 16 or more cells decreased. The results of this study imply that percentage of colonies with 16 or more cell is useful as a indicator of in vitro human skin fibroblast aging and may estimate the in vivo donor age.

• Parasites, Hosts and Diseases
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• v.33 no.4
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• pp.387-390
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• 1995

In the present communication, YS-27, a Korean strain of Entnnloeba histoIWtica is described for the isolation and establishment of axonic cultivation. 5. histoLvticc, designated as strain "YS-27" was isolated from the pus of a hepatic abscess obtained from a 72 you old inpatient of August 10, 1969. Specimens, were obtained by needle aspiration, inoculated immediately and weekly cultured in a modified diphasic medium at 37℃. Strain YS-27 had been maintained for more than 15 years by weekly subculture until February, 1985. These cultures were transferred to a monoxenic TTY-SB medium seeded with a trypanosomatid of the genus CyithidiG. Penicillin G, 2 to 10 H 103 International units and Streptomycin, 2 to 10 mg per 100 ml, were added to the cultures to eliminate the bacteria. After more than one year later, these two organisms were well maintained by transfer every 3 or 4 days until .January. 1986 at 37℃ in TTY-SB medium in the absence of other microorganisms. These monoxenic cultures were then transferred to TYI-S-33 medium. Strain YS-27 alone had not been growing at the time of transfer, but when overlaid with Crithinia at intervals of 3 to 4 days, strain YS-27 propagated well. The Clthidio died out several weeks later after several passages. Beginning in April, 1986, strain YS-27. was successfully established in axonic culture in TYI-S-33 medium and has been maintained in continuous culture and multiplied well to present.

• Journal of Plant Biotechnology
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• v.41 no.2
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• pp.89-93
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• 2014

Long-term subcultured rose embryogenic calluses, which had been maintained for more than 5 to 6 years since the first embryogenesis from calluses induced from in vitro roots of rose, were identified as potential material for the development of transgenic plants. The first embryogenic calluses from 'Sweet Yellow' and two breeding lines (KR056002 and KR056006) were obtained in 2007 and 2009, respectively. Subsequently, we found that plants regenerated from long-term embryogenic calluses (LEC). Whereas the LEC from 'Sweet Yellow' takes 3 to 4 months to regenerate plants, those of the two breeding lines take 4 to 5 months. This period of time is the same as that taken for plants to regenerate from the first embryogenic callus. New embryogenesis was observed from atypical bodies (ABs) that appeared during the process of long-term subculture. We found that it is possible to use the AB as a material for new embryogenesis.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.71-75
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• 1997

For the establishment of early selection of heat-tolerant clones through in vitro tuberization of true potato seeds, different temperature treatments for in vitro tuberization were investigated. The ratios of tuberization at 2$0^{\circ}C$ on var. Superior and DTO-33 treated with 5 mg/L of BAP and 500 mg/L of CCC, were 85% and 92%, respectively. At 3$0^{\circ}C$, the ratio of tuberization on DTO-33 was 37%, which revealed strongly heat-tolerant clone. In culture system of in vitro tuberization, the number of tubers per flask at 2$0^{\circ}C$ on non-subculture incubation was more than that on subculture incubation. The condition of non-subculture and short-day treatment for 4 weeks was good for production as 10.6 tubers per flask, which was very similar to that of long-day treatment. On the other hand, tuber diameter on long-day treatment was greater as 11.2 mm than on short-day treatment. Therefore, in vitro tuberization from true potato seeds could be induced under the condition of long-day treatment at darkness.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.169-174
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• 2008

The growth characteristics of Paecilomyces tenuipes according to the passage in the two kind of liquid media were investigated by comparing the mycelium and conidium formation degrees. The potato dextrose broth medium and the silkworm larvae medium containing the silkworm powder were used as the liquid media, and the potato dextrose agar medium and the brown rice medium containing the powder of silkworm pupa were used as the solid media. The conidium formation degree in liquid media differed by the passages but that in solid media was not. This suggested that the passage in liquid media did not affect significantly the conidium formation in solid media. When the brown rice media were inoculated with the concentration of $1{\times}10^{10}$ conidia/ml, $1{\times}10^8$ conidia/ml and $1{\times}10^6$ conidia/ml, respectively, the conidium formation degrees were similar. This indicated that the optimal inoculation concentration of conidium to the brown rice media is $1{\times}10^6$ conidia/ml.