• 한국가축번식학회지
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• 제25권3호
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• pp.243-250
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• 2001

본 연구는 미성숙 돼지 난포 난자의 체외성숙에 있어서 catalase (0.1 mg/$m\ell$)와 xanthine (5 mM)의 역할에 대하여 검토하였다. 그 결과, 체외에서 성숙배양 48시간 후 metaphase-II 단계로 발육한 난자의 비율은 xanthine (54%) 첨가 보다는 대조구 (72%), catalase (73%) 및 catalase+xanthine (70%) 첨가구에서 유의적으로 높은 성숙율을 나타냈다 (P＜0.05). 한편, 체외에서 30시간 동안 성숙배양한 경우 모든 실험구에서 성숙율의 유의적인 차이는 인정되지 않았으나, 성숙배양 36, 42 및 48시간 후 xanthine의 첨가 여부에 관계없이 catalase 무첨가 (29~50%) 보다는 첨가시 (49~70%)에 유의적으로 높은 성숙율을 나타냈다 (P＜0.05). 체외에서 xanthine의 첨가 또는 무첨가시 배양시간의 연장이 난자의 성숙에 미치는 영향을 검토한 결과 배양 72시간에서 높은 성숙율을 나타냈으며, 퇴행난자의 비율은 배양 120시간에서 catalase무첨가(47%)에 비하여 첨가시 (28%) 유의적으로 낮게 나타났으나 xanthine이 첨가된 배양액내에서 catalase첨가유무에 의한 차이는 인정되지 않았다. 또한 xanthine을 첨가하여 72시간 배양한 경우 단위발생란이 처음으로 관찰되었지만 catalase의 첨가 유무에 의한 차이는 인정되지 않았지만 배양시간이 길어짐에 따라 발생비율이 증가하였다. 이와 같은 결과에서 돼지 난포난자는 catalase와 xanthine을 첨가한 배양액내에서 배양 72시간까지 성숙율이 증가할 수 있으며, 배양기간의 연장시 catalase에 의하여 난자의 퇴행을 억제하며 단위발생란의 증가를 가져오는 것으로 생각된다.

• 한국식품영양학회지
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• 제1권2호
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• pp.64-67
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• 1988

Cadmium resistant cocobacillus B-17 from soil was tolerated up to 1600ug/ml of cadmium at agar plate and the strain B-17 was able to grow at 600ug/ml of cadmium at liquid medium after the lag phase being prolonged with lengthening culture time. Optimal pH of the strain was shown at pH7.0. The elimination frequency of cadmium resistance by 10ug/ml of acriflavin was 28%, and by 20ug/ml of ethidium bromide was 47%, respectively.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.42-48
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• 1998

In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.539-544
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• 2013

The effects of culture depth (2-10 cm) and cell density on the growth rate and biomass productivity of Chlorella sp. XQ-200419 were investigated through the use of a self-designed open circular pond photobioreactor-imitation system. With increases in culture depths from 2 to 10 cm, the growth rate decreased significantly from 1.08 /d to 0.39 /d. However, the biomass productivity only increased slightly from 8.41 to 11.22 $g/m^2/d$. The biomass productivity (11.08 $g/m^2/d$) achieved in 4 cm culture with an initial $OD_{540}$ of 0.95 was similar to that achieved in 10 cm culture with an initial $OD_{540}$ of 0.5. In addition, the duration of maximal areal productivity at a 4 cm depth was prolonged from 1 to 4 days, a finding that was also similar to that of the culture at a 10 cm depth. In both cases, the initial areal biomass densities were identical. Based on these results and previous studies, it can be concluded that the influence of culture depth and cell density on areal biomass productivity is actually due to different areal biomass densities. Under suitable conditions, there are a range of optimal biomass densities, and areal biomass productivity reaches its maximum when the biomass density is within these optimal ranges. Otherwise, biomass productivity will decrease. Therefore, a key factor for high biomass productivity is to maintain an optimal biomass density.

• Parasites, Hosts and Diseases
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• 제48권1호
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• pp.61-65
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• 2010

The objectives of this study were to conduct a prevalence survey of trichomoniasis in pregnant women and to evaluate the utility of different methods for its diagnosis. A total of 597 vaginal exudates from pregnant women who were examined at the Hospital de Clinicas in Buenos Aires, Argentina from 1 August 2005 to 31 January 2007, were prospectively and consecutively evaluated. The investigation of Trichomonas vaginalis was made by different microscopic examinations, and culture on liquid medium. The sensitivity and specificity of the microscopic examinations were assessed considering culture on liquid medium as the "gold standard". The prevalence of T. vaginalis obtained by culture on liquid medium was 4.0% (24/597). The prevalence of T. vaginalis obtained by direct wet smear, prolonged May-Grunwald Giemsa staining, and sodium acetate-formalin (SAF)/methylene blue staining-fixing technique was 1.8%, 2.3% and 2.5%, respectively. The sensitivity of the direct wet smear was 45.8%, that of the prolonged May-Grunwald Giemsa staining was 58.3%, and that of the SAF/methylene blue method was 62.5%. Considering the 3 microscopic examinations altogether, the sensitivity rose to 66.7% and the specificity was 100% for all of them. This is the first time that the prevalence data of T. vaginalis by culture in pregnant women are published in Argentina. Due to the low sensitivity obtained by microscopy in asymptomatic pregnant women, the use of the liquid medium is recommended during pregnancy, in order to provide an early diagnosis and treatment.

• BMB Reports
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• 제50권11호
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• pp.572-577
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• 2017

In most clinical applications, human mesenchymal stem cells (hMSCs) are expanded in large scale before their administration. Prolonged culture in vitro results in cellular senescence-associated phenotypes, including accumulation of reactive oxygen species (ROS) and decreased cell viabilities. Profiling of stem cell-related genes during in vitro expansion revealed that numerous canonical pathways were significantly changed. To determine the effect of selenocysteine (Sec), a rare amino acid found in several antioxidant enzymes, on the replicative senescence in hMSCs, we treated senescent hMSCs with Sec. Supplementation of Sec in the culture medium in late-passage hMSCs reduced ROS levels and improved the survival of hMSCs. In addition, a subset of key antioxidant genes and Sec-containing selenoproteins showed increased mRNA levels after Sec treatment. Furthermore, ROS metabolism and inflammation pathways were predicted to be downregulated. Taken together, our results suggest that Sec has antioxidant effects on the replicative senescence of hMSCs.

• 한국수학사학회지
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• 제31권4호
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• pp.169-181
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• 2018

We here discuss about the roles and meaning of Joseon mathematics in the history of Asian mathematics from cultural perspective. To do so, we focus on culture. We first look at the meanings and the definitions of the terms, civilization and culture, and their differences. We next discuss on the cultural perspective to look at the mathematical history of Korea, which is considered as a part of the history of Asian mathematics. It is notable that Joseon mathematics of Korea made Asian mathematics develop further, and played the roles of academic bridges among China, Korea and Japan. It also kept and prolonged the life of the Asian mathematics up to the beginning of the 20th century.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권5호
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• pp.350-354
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• 2000

The growth promotion of a Taxus brevifolia cell suspension culture was investigated using conditioning factors. The conditioning factors produced and secreted from cultured cells usually stimulate cell division and the production of secondary metabolites. Therefore, the effective incubation time for the optimal secretion of conditioning factors was firstly determined for the promotion of cell growth. Conditioned media obtained by cultivating for 2 and 5 days showed the promotion of initial cell growth during the early cell growth period. However, the positive effect of the conditioning factors on the initial cell growth did not continue because of the depletion of the medium nutrients. Accordingly, the addition of a carbon source to the conditioned medium prolonged the positive effect on the cell growth. The addition of sucrose to the conditioned medium resulted in the maximum cell density being reached 4 days earlier compared to the control group and an increased substrate yield.

• Journal of Ginseng Research
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• 제40권4호
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• pp.409-414
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• 2016

Background: The low survival rate of in vitro regenerated Panax ginseng plantlets after transfer to soil is the main obstacle for their successful micropropagation and molecular breeding. In most cases, young plantlets converted from somatic embryos are transferred to soil. Methods: In vitro thickened taproots, which were produced after prolonged culture of ginseng plantlets, were transferred to soil. Results: Taproot thickening of plantlets occurred near hypocotyl and primary roots. Elevated concentration of sucrose in the medium stimulated the root thickening of plantlets. Senescence of shoots occurred following the prolonged culture of plantlets. Once the leaves of plantlets senesced, the buds on taproots developed a dormant tendency. Gibberellic acid treatment was required for dormancy breaking of the buds. Analysis of endogenous abscisic acid revealed that the content of abscisic acid in taproots with senescent shoots was comparatively higher than that of taproots with green shoots. Thickened taproots were transferred to soil, followed by exposure to gibberellic acid or a cold temperature of $2^{\circ}C$ for 4 mo. Cold treatment of roots at $2^{\circ}C$ for 4 mo resulted in bud sprouting in 84% of roots. Spraying of 100 mg/L gibberellic acid also induced the bud sprouting in 81% roots. Conclusion: Soil transfer of dormant taproots of P. ginseng has advantages since they do not require an acclimatization procedure, humidity control of plants, and photoautotrophic growth, and a high soil survival rate was attained.

• Pediatric Infection and Vaccine
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• 제28권3호
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• pp.160-167
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• 2021

비장티푸스 살모넬라균에 의한 화농성 척추염은 면역이 정상인 소아청소년에서는 매우 드문 질환으로, 주로 면역저하자나 낫적혈구병과 같은 혈색소병을 가진 환자들이 이 질환의 위험군으로 알려져 있다. 본 증례는 발열과 우상복부 통증으로 내원한 정상 면역을 가진 건강한 13세 청소년에서 대변 배양 검사를 통하여 비장티푸스 살모넬라균을 확인하고, 지속된 발열에 대하여 추가 영상 검사를 통하여 화농성 척추염이 합병되었음을 확인한 증례로, 불명열의 검사로 배양 검사의 중요성을 인식하게 하고, 일반적이지 않은 살모넬라증의 임상경과를 보이는 경우에는 장외 국소감염의 합병증에 대하여 철저하게 조사하는 것이 중요함을 보여준다.