• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.128-131
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• 1996

Lactobacillus acidophilus KFRI 233 (of human origin) exhibited a high tolerance to bile. The maximum cell yield was 6.6${\time}10^9 CFU$ per gram of whey in a 5.0% whey medium. Cell growth was improved with the addition of 0.5% thiotone and 0.25% calcium carbonate. Cell growth reached a maximum level of 5.4${\times}10^8$ CFU/ml at 20 h. Eighty-nine percent of the viable cells in the centrifuged concentrate survived freezing at $-70^{\circ}C$ and this frozen concentrate showed no reduction in the viable cell count after 30 days at $-70^{\circ}C$. Eight percent of the viable cells survived freeze-drying after the addition of 1 g/l sodium carbonate before harvesting by centrifuging and this freeze-dried concentrate showed only a slight reduction in the viable cell count after 30 days at $4^{\circ}C$.

• Journal of Chest Surgery
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• v.26 no.2
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• pp.80-85
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• 1993

Synthetic and biosynthetic vascular grafts of small diameter have long been considered to be prone to thrombosis, ultimately leading to the complete graft occlusion. Endothelial cell seeding onto synthetic blood-contacting surfaces has been suggested to be an ideal means to solve this problem. This study described a culture method of bovine endothelial cells and evaluated blood-compatibility and seeding efficiency of cultured endothelial cells. Bovine pulmonary artery endothelial cells were harvested enzymatically and grown to confluence on polystyrene culture flask surfaces using established techniques. The identification of endothelial cells was made through the demonstration of expression of factor VIII R:Ag by immunofluorescent technique. To quantitate the effect of improvement in blood-compatibility of viable endothelial cells, endothelial monolayers were exposed to blood containing $\^$111/In-oxine labeled platelets. Viable endothelial monolayers retained less labeled platelets than control surfaces. The Indium-labeled endothelial cells were seeded onto three different blood-contacting surfaces of Dacron vascular graft immobilized in specially equipped wells and incubated for specific time intervals (t=15, 30, 60, 120 minutes). Longer incubation times showed improved cell adherence in collagen-coated and fibrin-coated Dacron vascular graft groups. However in untreated Dacron grafts, no direct relationship was observed between incubation time and endothelial cell seeding efficiency. This may be due to leakage of endothelial cells through porosity of Dacron grafts in this in-vitro experimental condition.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.2
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• pp.131-134
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• 2004

This study was carried out to investigate the shelf life of Shepherd's purse(Capsella bursa-pastoris) Kimchi during fermentation at 1$0^{\circ}C$. Capsella bursa-pastoris was treated without or with blanching. The viable cells of lactic acid bacteria(LAB) of raw and blanched Kimchi after fermentation for 15 days at 1$0^{\circ}C$ were 7.91 log CFU/mL and 6.4 log CFU/mL, respectively. The viable cells of LAB of Capsella bursa-pastoris Kimchi at 1$0^{\circ}C$ were lower in the blanched one when compared to the raw one. The pH of raw Kimchi was lower than that of the blanched one during fermentation for 25 days at 1$0^{\circ}C$. The viable cells of total bacteria of the blanched Kimchi were lower than that of non-blanched one during fermentation at 1$0^{\circ}C$. The ascorbic acid and chlorophyll contents decreased more in the blanched Kimchi when compared to that treated without heat. The sensory quality of the blanched Kimchi was a little inferior to that treated without heat during fermentation.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.553-558
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• 1997

Frozen cod fillet block(7.0$\times$4.6$\times$0.6cm, 18$\pm$0.5g) was purchased from a supermarket in Taegu area. Three experimental groups of fish fillet, frozen-thawed cod fillet refrigerated at 5$^{\circ}C$(R), frozen at -2$0^{\circ}C$(F) and repeated freezing and refrigerating(RFR) every other day, were incubated at each temperature. Changes in the viable counts of mesophiles and psychrotrops, the amount of free drip and pH of cod muscle during cold storage were 6.5$\times$104 and 7.4$\times$103 CFU/g of muscle, respectively. The viable counts of cod muscle R and FRF exceeded 107 CFU/g within 8 days and 16 days, respectively, while the viable counts of cod muscle F were not exceeded 107 cells/g throughout the storage period. The viable counts of psychrotrops exceeded that of mesophiles at the end of cold storage period. The viable counts of cod muscle showed positive correlation with pH(r=0.73-0.96,the highest in RFR) during cold storage. The amount of free drip in cod muscle R, F and RFR was 27.06$\pm$9.75, 27.56$\pm$8.02 and 33.97$\pm$10.70%, respectively. The amount of free drip in RFR increased as the progress of storage.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.145-149
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• 1986

The development of delayed-type hypersensitivity(DTH) reaction to Staphylococcus aureus in mice was studied, Mice received 3 injections of $10^8$ viable S. aureus subcutaneously showed a marked footpad swelling when mice were challenged with $10\;{\mu}g$ staphylococcal protein antigen into footpad(The percent increase of footpad thickness at 24 h after challenge wsa 35% approximately). Histological observation of footpad of immunized mice showed a marked thickness of subcutaneous tissue due to edematous reaction and massive infiltration of lymphocytes and neutrophils which are characteristic cells in DTH reaction. Intensity of DTH reaction of mice immunized with viable bacteria was much higher than that of mice immunized with staphylococcal protein or heat-killed bacteria. The DTH reaction to S. aureus could be transferred to normal recipient mice by both spleen cells and lymph node cells.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.254-261
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• 2005

The over-expression of Bcl-2 has greatly improved the culture period, specific growth rate, and maximum viable cell density of NS0 cells culture under low serum condition. Further analysis of these data suggests that a saturation model of the Monod type can be used to represent the relationships of specific growth rate and initial serum concentration. The ${\mu}_{max}$ and $K_s$ for the Bcl-2 cell line is $0.927day^{-1}\;and\;0.947\%(v/v)$ respectively, which are $21\%$ greate and $7\%$ lower respectively than its control counterpart. Study on the amino acid supplementation revealed that Bcl-2 cell lines possess greater improvement in the specific growth rate and maximum viable cell density compared to the control cell lines. A further increase in the amino acid supplementation has resulted a $17\%$ decrease in specific growth rate and no improvement in maximum viable cell density in the control culture. However, the Bcl-2 cell line exhibited a better growth characteristic in this culture condition compared to that of control cell lines. The higher specific growth rate and maximum viable cell density of the Bcl-2 cell line in medium fortified with serum and MEM EM suggested a more efficient nutrient metabolism compared to that in the control cell line. The low serum and amino acid utilisation rate and the higher cell yield may prove to be important in the development of serum/protein free culture.

• The Journal of the Korean Society for Microbiology
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• v.21 no.4
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• pp.407-415
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• 1986

This study investigated whether a correlation exists between environmental physical and biochemical factors and adherence of Candida albicans to human buccal epithelial cells by using normal and UV-irradiated strains. The results were as follows: 1. The percentage of germ tube forming activities of normal Candida albicans was 91.5% and UV-irradiated Candida albicans was 15.0%. The $LD_{50}$ of normal strains in mice were $1.0{\times}10\;cells/ml$, but could not be observed in the UV-irradiated strains even with $1.0{\times}10\;cells/ml$. It demonstrated that the virulence is decreased in the UV-irradiated strain. 2. The adherence of normal Candida albicans to human buccal epithelial cells($166{\pm}29{\sim}207{\pm}17\;cells$/100 epithelial cells) was significantly greater than UV-irradiated Candida albicans($99{\pm}21{\sim}131{\pm}25\;cells$/100 epithelial cells). 3. Candida albicans cultured at $37^{\circ}C$ adhered to buccal epithelial cells($166{\pm}16{\sim}207{\pm}17\;cells$/100 epithelial cells) in greater numbers than cultured at $25^{\circ}C$($80{\pm}15{\sim}143{\pm}22\;cells$/100 epithelial cells). 4. On comparison of the adherence of viable and nonviable(heat-killed) Candida albicans to human buccal epithelial cells, the nonviable Candida albicans demonstrated poorer adherence than viable Candida albicans. 5. Adherence in vitro of Candida albicans to human epithelial cells appeared to be effected by the pH. The adherence ability was maximum increased at pH 7.0($187{\pm}22\;cells$/100 epithelial cells) other than experimental pH. 6. The adherence was proportional to the incubation time and the Candida cell concentration in the suspension. 7. A strong correlation was shown between germ tube forming activity and increased adherence of Candida albicans to human epithelial cells, indicating that germ tube forming activity were responsible for candidal virulence.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.918-922
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• 2001

In a previous study, we have isolated a number of lactobacilli from Korean women, and one of them (KLB46) was identified as Lactobacillus crispatus by 16S rRNA gene sequencing. For the ecological treatment of bacterial vaginosis (BV) cell suspension of L. crispatus KLB46 was instillated into BV patients. L. crispatus KLB46 was found to persist for several days in cell suspension with no nutrients. In this study, in order to assess the influence of starvation on physiological activity, we compared the viability and culturability of KLB46 following suspension in various buffer solutions. A pair of in situ fluorescent dye was used to assess viability (i.e. membrane integrity) and the culturability was examined by plate count assay. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit $(BacLight^{TM})$ was applied to estimate both viable and total counts of bacteria in cell suspension. $BacLight^{TM}$ is composed of two nucleic acid-binding stains ($SYTO\;9^{TM}$ and propidium iodide). $SYTO\;9^{TM}$ penetrates all bacterial membranes and stains the cells green while propidium iodide only penetrates cells with damaged membranes, therefore the combination of the two stains produces red fluorescing cells. Optimal staining conditions for $BacLight^{TM}$ were found to be with 0.0835M $SYTO\;9^{TM}$ and 0.05M propidium iodide for 15 min incubation at room temperature in dark. When cells were microscopically examined during 140 hours of starvation, the culturability decreased markedly while the viability remained relatively constant, which suggests that large fraction of KLB46 cells became viable but non-culturable (VBNC) upon starvation.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.374-377
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• 2003

Hybridoma cells were adapted in media containing up to 80 mM $K^+$. The adapted cells obtained tolerance at high osmotic pressure and low pH. The adapted cells showed a maximum viable cell density of $1.1{\times}10^6$ cells/ml when a batch culture was progressed in a nutrient-fortified medium with Erlenmeyer flask at 450 $mOsm/kgH_2O,$ as compared to $4.8{\times}10^5$ cells/ml for non-adapted cells grown under the same conditions. The adapted cells also showed a maximum viable cell density of $7.8{\times}10^5$ cells/ml with the same method at initial pH 7.0 as compared to $5.3{\times}10^5$ cells/ml for non-adapted cells. Adaptation of animal cells at high $K^+$ levels may therefore lead to an improvement of their performance at limited conditions.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.299-304
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• 1998

Despite the rapid development of assisted reproductive technologies (ART) in recent years, implantation rates after replacement of embryos into the uterine cavity remains low. Several techniques such as culture conditions based on formulations of human tubal fluid and various ART techniques as GIFT, ZIFT, TET have been adopted in recent years to improve embryo viability in vitro and implantation rates. Also, coculture of human IVF-derived embryos have been used in an effort to increase the number of viable embryos following IVF and to improve synchrony between the developing embryo and the uterine environment. The aim of this study was to evaluate whether the use of co culture with autologous cumulus cells has a significant beneficial effect on the development of embryos in vitro and its relation to the pregnancy rates in 120 patients with previous failed IVF-ET from September, 1995 to January 1998. We obtained the results from which significant improvement in the quality of viable embryos were observed using a coculture system with autologous cumulus cells, but pregnancy rates in this group of patients did not differ from the rate in the standard IVF group during the same period. Our study shows that a simplified short-term coculture system with autologous cumulus cells may help rescue moderate quality embryos to cleave regularly.