• Biotechnology and Bioprocess Engineering:BBE
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• 제7권3호
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• pp.163-170
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• 2002

This report describes the use of a transtubular bioreactor to study the relative effects of diffusion versus perfusion of medium on antibody production by a hybridoma cell line. The study was performed with a high-density cell culture maintained in a serum-free, low-protein medium for 77 days. It was determined that the reactor possessed a macro-mixing pattern residence time distribution similar to a continuous stirred tank reactor (CSTR), However, due to the arrangement of the medium lines in the reactor, the flow patterns for nutrient distribution consist of largely independent medium path lengths ranging from short to long. When operated with cyclic, reversing, transtubular medium flow, some regions of the reactor (with short residence times) are more accessible to medium than others (with long residence times). From this standpoint, the reactor can be divided into three regions: a captive volume, which consists of medium primarily delivered via diffusion; a lapped volume, which provides nutrients through unilateral convection; and a swept volume, which operates through bilateral convection. The relative sizes of these three volumes were modified experimentally by changing the period over which the direction of medium flow was reversed from 15 min (larger captive volume) to 9 h (larger swept volume). The results suggest that antibody concentration increases as the size of the diffusion-limited (captive) volume is increased to a maximum at around 30 min with a sharp decrease thereafter. As reflected by changes in measured consumption of glucose and production of lactate, no significant difference in cellular metabolism occurred as the reactor was moved between these different states. These results indicate that the mode of operation of the transtubular bioreactor may influence antibody productivity under serum-free, low-protein conditions with minimal effects on cellular metabolism.

• Nutrition Research and Practice
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• 제5권5호
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• pp.396-403
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• 2011

Ceramides (Cer) comprise the major constituent of sphingolipids in the epidermis and are known to play diverse roles in the outermost layers of the skin including water retention and provision of a physical barrier. In addition, they can be hydrolyzed into free sphingoid bases such as $C_{18}$ sphingosine (SO) and $C_{18}$ sphinganine (SA) or can be further metabolized to $C_{18}$ So-1-phosphate (S1P) and $C_{18}$ Sa-1-phosphate (Sa1P) in keratinocytes. The significance of ceramide metabolites emerged from studies reporting altered levels of SO and SA in skin disorders and the role of S1P and Sa1P as signaling lipids. However, the overall metabolism of sphingoid bases and their phosphates during keratinocyte differentiation remains not fully understood. Therefore, in this study, we analyzed these Cer metabolites in the process of keratinocyte differentiation. Three distinct keratinocyte differentiation stages were prepared using 0.07 mM calcium (Ca$^{2+}$) (proliferation stage), 1.2 mM Ca$^{2+}$ (early differentiation stage) in serum-free medium, or serum-containing medium with vitamin C (50 ${\mu}L$/mL) (late differentiation stage). Serum-containing medium was also used to determine whether vitamin C increases the concentrations of sphingoid bases and their phosphates. The production of sphingoid bases and their phosphates after hydrolysis by alkaline phosphatase was determined using high-performance liquid chromatography. Compared to cells treated with 0.07 mM Ca$^{2+}$, levels of SO, SA, S1P, and SA1P were not altered after treatment with 1.2 mM Ca$^{2+}$. However, in keratinocytes cultured in serum-containing medium with vitamin C, levels of SO, SA, S1P, and SA1P were dramatically higher than those in 0.07- and l.2-mM Ca$^{2+}$-treated cells; however, compared to serum-containing medium alone, vitamin C did not significantly enhance their production. Taken together, we demonstrate that late differentiation induced by vitamin C and serum was accompanied by dramatic increases in the concentration of sphingoid bases and their phosphates, although vitamin C alone had no effect on their production.

• 한국수정란이식학회지
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• 제13권2호
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• pp.139-145
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• 1998

In the present study, effects of interleukin-2 (IL-2), a differentiator and proliferator of T-cells, on nuclear maturation and sperm penetration of bovine oocytes was examined in a serum-free or serum-containing medium. Basic medium was used TCM-199 supplemented with 2.2g / ι sodium bicarbonate, 100 i.u. /rnl penicillin. 100$\mu$g /ml streptomycin, 0.25$\mu$g/ml Fungizone, this medium treated with FCS and IL-2. In experiment 1, we examined the effect of the addition of 0, 1, 5, 10 or 15nM /ml IL-2 to tissue culture medium (TCM-199) on nuclear maturation of oocytes Development of oocytes to the Metaphase II (M II) stage (%) was significantly (P<0.05) higher at 1, 5,10 and 15 nM /ml IL-2(54.2, 73.5, 80.0 and 69.6%, respectively) than at 0 nM /ml IL-2(35.7%). In experiment 2, we examined the effect of the addition of l0nM /ml IL-2 or 5% FCS in oocyte maturation. Nuclear maturation rates were significantly(P<0.05) higher l0nM /ml IL-2(80%) than non-treatment(35.7%) and 5% FCS(63.6%) treatment. On the other hand, there were no significant difference in the proportion of oocytes developed to the 2-cell stage after addition of IL-2 and/or FCS. These results suggest that IL-2 supports nuclear maturation of bovine immature oocytes in vitro. Serum-free maturation system using IL-2 might be useful for evaluation of various factors on oocyte maturation.

• KSBB Journal
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• 제13권2호
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• pp.181-186
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• 1998

부착의존성 세포주인 Trichoplusia ni 의 유래의 BTI-TN5B1-4 (TN5) 곤충세포주를 이용하여 인간 혈소판생성축진인자인 재조합 인간 트롬보포이에틴(rhTPO)의 배양조건 최적화 연구를 수행하였다. 배양배지, 세포감염에 투입되는 재조합 베큘로바이러스와 숙주세포의 비율(MOI),세포감염시 세포밀도, 배지 회수시간 및 배양방법 등이 rhTPO 의 생산에 미치는 효과를 연구하여 60 mm dish로 정체 배양시 10 MOl 이상,$2\times10^6$ cells 의 세포밀도,바이러스 감염 후72 시간에서 rhTP0 의 최대 발현양 (약 12 mg/L)을 나타내었다. 배양 배지로서는 EXCELL FIVE 배지가 SF900II나Insect serum free media-1 Figure 5. Effect of growth phases on rhTPO production. TN5 cells were grown as suspension culture in 1 L spinner flask with 200 mL of SF900II serum free medium at 80 rpm. The cells were infected with AcBac404-2 at MOl of 1. Culture medium was collected at given time intervals and the expression level of rhTPO was analyzed by ELISA (A) or immunoblot analysis (B). Lanes 1 and 7; cell density of $0.6\times10^6$ cells/mL, lanes 2 and 8; cell density of $1.6\times10^6$ cells/mL, lanes 3 and 9; cell density of $2.0\times10^6$ cells/mL, lanes 4 and 10; cell density of $3.0\times10^6$ cells/mL, lane M; prestained molecular weight marker (Bio-Rad). Lanes 1, 2, 3, and 4; culture medium was collected at 48 hpi and lanes 7, 8, 9, and 10; culture medium was collected at 72 hpi. Figure 6. Effect of culture media on rhTPO production. TN5 cells grown with different culture media were infected with AcBac-404-2 at 10 MOL 10$\mu$L of culture medium was run on SDS-PAGE and Immunoblot analysis was performed. Lane ];TN5 cells cultured with SF900II serum free media(Gibco),and lane 3; TN5 cells cultured with EXPRESS FIVE serum free media (Gibco) 에 비해 더 증가된 발현양을 나타내었다. TN5 세포주를 0.2 L 규모 (1 L spinner flask)oJl에서 세포간의 응집현상 없이 부유배양에 적응,배양시킨 후 세포성장 시기에 따른 발현을 조사한 결과 1 MOI의 감염조건 하에서는 $0.6\times10^6$cell/mL의 early exponential시기의 세포밀도에서 72시간 배양하였을 대 최대 발현양을 나타내었다. 나타내었다.

• 약학회지
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• 제43권1호
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• pp.85-90
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• 1999

FTY720, a novel immunosuppressant, elevated the level of endogenous sphingoid bases in a dose-dependent manner within 3 hr in $LLC-PK_1$ cells. The relative molar ratio of sphingoid bases expressed as sphingosine/sphinganine (SPN/SPA), a biomarker of altered sphingolipid biosynthesis, in $10{\;}{\mu}M$ of FTY720 showed tow-fold increase as compared with the one in control culture. FTY720 under the serum-free medium condition increased only cytosolic free sphingosine concentration, not sphinganine concentration in a time-dependent manner over the 8 hr incubation under the same condition as in serum free cultures, the SPN/SPA ratio began to fluctuate and the number of floating cells as an indicator of cytotoxicity was increased 8 hr after the addition of FTY720 to cultured cells. These results suggest that the process of FTY720-induced cell death in $LLC-PK_1$ cells.

• Preventive Nutrition and Food Science
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• 제3권4호
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• pp.362-367
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• 1998

Thyroid hormone(T3) stimulates hepatic lipogenesis by increasing expression of genes, indluding acetyl-CoA carboxylase and fatty acid synthase. S14 protein, which is thougth to be involved in lipid metabolism , appears to respond in parallel . Effect of T3 on lipogenesis in white and brown adipose tissue are less clear, and may be complicated by indirect effects of the hormone. We developed an adipocytes system where the indirect effects of thyroid hormone are abolished and direct effects of T3 on lipogenesis could be tested. Fat accumulation was mesured by Oil-Red O staining. Insulin clearly enhanced fat accumulation by 2-fold . Isobutylemethylxanthie(IBMX) apeared to inhibit insulin -stimulated fat accumulation. Dexamethasone increased insulin-stimulatedfat accumulation about 1.3-fold. confluent adipocytes were cultured in serum-free medium or medium containing 10% fetal calf serum or 10% fetal calf serum stripped of thyroid hormone and lipogenesis, assessed by the incorporation of 3H2O , was measured. Medium without serum or supplemented with T3-depleted serum did not amplify the stimulatory effect of T3 on lipogenesis compared to medium containing 10% fetal calf seru. Dexamethasone alone led to a decrease inlopogenesis of about 50 % in white adipocytes and 25% in brown adipocytes. However, dexamethasone amplified the lipogenic respnse to T3 by about 30% in whit eadipocytes and 60% in brown adipocytes. T3(1$\mu$M) stimulated lipogenesis and acetyl-CoA carboxylase and fatty acid syntase mRNA levels up to 2 -fold in both types of adipocytes. It seems that these adipocytes systems are as useful model to study the effects of hormones on lipogenic gene expression as well as lipogenesis.

• 한국가축번식학회지
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• 제10권1호
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• pp.109-120
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• 1986

This study was conducted to define the effect of addition of lysolecithin (LC) and 20% v/v rabbit serum to sperm preincubation medium on the induction of acrosome reaction (AR) an fertilizing ability in vitro of LG-added sperm. Ejaculated rabbit sperm from New Zealand White buck was washed once by centrifugation, then preincubated for 2 or 4 hrs in a chemically defined medium (DM), DM plus 20% rabbit serum or BSA-free DM plus 20% rabbit serum at 37$^{\circ}C$ water bath or CO2 incubator. At the end of preincubation LC was added to the preincubated sperm, which was stained at 0.5 to 4 hr later and examined for AR and sperm motility. For in vitro fertilization, gametes were coincubated in DM up to 24 hrs and thereafter fertilized embryos were incubated in BSM -II up to 48 hrs. Addition of LC to 4-hr preincubated sperm was more effective for the AR and sperm motility than that to 2-hr preincubated sperm and optimal concentration of LC for AR was about 80${\mu}$g/ml. A significant increase in AR occured from 20 to 30 min. after addition of 80 to 100${\mu}$g/ml in 4-hr preincubated sperm. BSA-free DM plus 20% rabbit serum showed a higher AR and sperm motility than those of DM plus 20% rabbit serum in LC-added sperm after 4-hr preincubation. The incidence of AR after 4-hr preincubation and at 30 min after 60${\mu}$g/ml LC addition varied greatly among individual bucks. Sixty ${\mu}$g/ml LC-added sperm showed a slight high cleavage rate over control levels, but 100${\mu}$g/ml LC-added sperm showed lower cleavage rate rather than 60${\mu}$g/ml LC. It is concluded that optimal concentration of LC for high AR induction and sperm motility in 4-hr preincubated sperm was about 80${\mu}$g/ml, but 60${\mu}$g/ml level was more useful for in vitro fertilization.

• 한국수산과학회지
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• 제39권1호
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• pp.23-26
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• 2006

Effects of sera from several fish species and insulin on the development of cultured Silurus asotus hepatocytes were investigated. Hepatocytes with high viability (95%) were obtained from the livers of male catfish by two step collagenase perfusion. Isolated hepatocytes, initially showed a typical round-shape, firmly attached to the culture dish within 24 h. In the presence of catfish serum, hepatocytes attached each other, spread well on the dish and developed into monolayer after 3-4 days of incubation. Cells within the established monolayer became polygonal in shape and their nuclei and boundaries being clearly visible under the microscope. In contrast, when incubated in FBS-supplemented or serum-free medium, cells managed to form small clusters, each made of 2-10 cells. Cells in FBS-supplemented medium further developed into larger clusters. However, these clusters failed to develope into monolayer. In addition, when insulin was deprived from culture medium, formation of monolayer also failed. From these data, it can be concluded that the presence of both catfish serum and insulin is necessary for the formation of monolayer of catfish hepatocytes and the functional role of fish serum may differ from that of insulin and can not be displaced by FBS-supplementation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.142-146
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• 2003

Three insect cell lines, Sf9, Sf21 and Tn5Bl-4, and four different kinds of serum free media (SFM), Sf 900 II, EX-CELL 420, EX-CELL 405 and Express Five, were used to compare the nutrient consumption, byproduct formation, production of recombinant protein and protease activity in suspension cultures. The Sf 900 II SFM was a ppropriate for the cell growth and protein production of the Sf9 and Sf21 cell lines. When the Tn5Bl-4 cell line was grown in the Express Five SFM, the specific growth rate was 1.6 fold higher than those of either the Sf9 or Sf21 cell lines. The glucose and glutamine consumption rates per cells, were 4 and 2.3 times higher than those of the Sf9 cell line, respectively. The overall yield coefficients of the lactate and ammoniumion were 2.8 and 1.5 times higher compared to those of the Sf9 cell line. respectively. The maximum specific ${\beta}$-galactosidase production rate was 4.5 fold that of the Sf9 cell line, a 3 times higher protease activity per cell.

• 한국가축번식학회지
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• 제27권4호
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• pp.339-347
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• 2003

The purpose of this study was to investigate the development of bovine nuclear transfer (NT) embryos cultured in serum-free conditions. Bovine NT embryos cultured in various culture conditions were compared blastocyst development, total cell number and apoptosis using TUNEL assay. In experiment 1, blastocyst rates of NT embryos were significantly higher (P<0.01) in FBS (22.0％) and BSA (26.6％) groups than in PVA (6.3％) group. Total cell number was significantly higher in FBS (78.4$\pm$19.4) and BSA (90.9$\pm$29.1) groups than in PVA group (46.0$\pm$0.0). Apoptotic cell number was significantly fewer in FBS (3.1$\pm$1.4) and BSA (1.7$\pm$1.4) groups than in PVA group (7.0$\pm$20.0) However, all of results were not different between the FBS and BSA group. In experiment 2, blastocyst rates of NT embryos were significantly higher (P<0.05) in fatty acid free-BSA (FAF-BSA) group (26.8％) than in fraction V-BSA group (11.2％). Total cell number were somewhat higher in FAF-BSA group (89.8$\pm$30.7) than in fraction V-BSA group (88.1$\pm$19.3). Apoptotic cell number were somewhat fewer in FAF-BSA (1.7$\pm$1.5) group than in fraction V-BSA group (4.2$\pm$2.9). These findings suggest that serum free condition were effective for the in vitro development of bovine NT embryos. Therefore, we concluded that fatty acid free-BSA has beneficial effect in development bovine NT embryos and can be use as a serum substitute.