• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.42-42
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• 2001

The objective of this study was to assess the development of porcine follicular oocytes fertilized by ICSI. Cumulus-oocyte-complexes (COCs) were collected by aspiration from follicles of 2-7 mm in diameter from a local slaughterhouse ovaries. Oocytes matured for 40-44 h were centrifuged at 12,000g for 6 min and then injected with sperm prepared by swim-up procedure in the presence or absence of 5 mM dithiothreitol (DTT). Injected oocytes were cultured in NCSU 23 medium during 6 to 8 days. IVF controls were compared to those of resulting embryos. The results obtained were as. follow: 1, The rates of cleavage and development rates into blastocyst by ICSI were not significantly (P<0.05) different between with (53.0% and 19.7%) or without (48.3% and 23.8%) centrifugation, respectively. 2. The cleavage and developmental rates to blastocyst after ICSI with or without 5mM DTT treated-sperm were not significantly (P<0.05) different (60.4% vs 16.4% and 48.5% vs 22.2%, respectively). 3. The cleavage and the developmental rates to blastocyst were not significantly (P<0.05) different between the zygotes obtained by IVF (51.8% vs. 22.4%) and ICSI (51.4% vs. 21.6%). 4. The number of blastomere in blastocyst stages after IVF or ICSI was not significantly different (46.7 $\pm$2.9 and 41.9$\pm$4.6).

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.433-439
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• 1986

Abundant amount of Chiamydia trachomatis could be amplified in mammalian McCoy cells and purified using descontinuous Uroarafin gradient centrifugation. As a chemical means io increase the Chlamydia trachomatis inclusions in McCoy cells IUdR treatment was found to be more effective than the cycloheximide treatment and was recommendanble for the proliferation of Chlamydia trachomatis. Centrifugation promoted Chlamydia trachomatis adhesion to McCoy cell surface, and maximal percentage of infected cells was obtained at about 3000g. The purified Chlamydia trachomatis could be kept in SPG solution for 48 hours at +4$^{\circ}C$ but for longer storage freezing to -7$0^{\circ}C$ was necessary.

• Journal of Periodontal and Implant Science
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• v.34 no.1
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• pp.93-100
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• 2004

많은 연구들에서 hMSC를 얻기 위해 centrifugation, fluoroscence activated cell sorter(FACS), magnetic activated cell sorter(MACS)가 이용되어져 왔다. 그러나 centrifugation만을 이용한 경우 순도가 떨어지며 FACS나 MACS의 경우에는 비용, 시간이 많이 드는 단점이 있다. 따라서 이 연구에서는 antibody cocktail을 이용하여 hMSC를 좀더 쉽게 얻어내는 방법에 대해 알아보았다. 사람의 골반에서 12G의 바늘을 이용하여 골수를 흡입한 후 heparin이 들어있는 시험관에 넣고 처리과정을 시행하기 전에 냉장고에 보관하며 가능한 한 빨리 처리 과정을 실시한다. 얻은 골수에 적당량의 RosetteSep( Stemcell Technologies)을 첨가한 후 실온에서 20분간 반응시킨다. 그 후 적당량의 Ficoll-paque위에 골수와 RosetteSep의 혼합물을 섞이지 않게 올리고 원심분리를 이용하여 원하는 세포층을 얻어낸다. 이 세포층을 따로 분리한 뒤 배양한다. 배양 시 세포가 80%이상 차기 전에 계속 passage를 시행하며 배양한다. 이는 세포가 밀도가 높아져 원치 않는 세포로 분화되는 것을 막기 위함이다. 배양된 세포가 다양한 분화능력을 가지고 있는지 알아보기 위해 세 가지로 분화를 유도하였다. 적절한 배지와 적절한 환경에서 배양함으로써 얻어진 세포를 osteoblast, chondroblast, adipocyte로 분화를 유도하였다. 분화된 세포가 원하는 형질의 세포로 분화되었는지를 확인하기 위하여 osteoblast의 경우 alizarin red staining, alkaline phosphatase activity, chondroblast의 경우 toluidine blue staining, adipocyte의 경우 Oil-Red-O staining으로 염색하여 분화를 확인하였다. 분리해낸 세포는 각각 세 가지 세포로 분화가 되었으며 이는 RosetteSep이 hMSC를 성공적으로 분리해냈다는 것을 보여준다. 그러나 모든 세포가 분화를 보이지는 않았으며 따라서 hMSC의 순도를 높이기 위한 연구가 더 필요하다. RosetteSep을 이용하면 다른 방법들 보다 쉽게 hMSC를 얻을 수 있으나 기존의 방법과 순도의 측면에서 더 비교할 필요가 있다.

• ALGAE
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• v.24 no.4
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• pp.257-265
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• 2009

Marine microalgae are a key diet component in finfish and shellfish aquaculture. Cryopreservation of the microalgae is suggested by many other studies as the best method for long-term storage. To test cryopreservation efficacy, 19 taxas of marine microalgal species were examined. In the first experiment we compared dimethylsulfoxide ($Me_2SO$) and glycerol, which are most widely used as cryoprotectant agents (CPAs). The cryopreservation comprised two freezing procedures. Firstly, the samples containing the CPAs were kept at $4^{\circ}C$ for 10 min before being plunged into liquid nitrogen ($-196^{\circ}C$). Secondly, samples containing CPAs were pre-cooled ($-1^{\circ}C$ $min^{-1}$ to $-80^{\circ}C$ before being plunged into liquid nitrogen. Most of the species were successfully cryopreserved using $Me_2SO$, whereas the Prasinophyceae (T. striata and T. suecica) were successfully cryopreserved using glycerol. In general, the cooling method had no influence on the survival of the microalgae except in the case of the Tetraselmis species. In the second experiment, the cultured solution was divided before cryopreservation into concentrated and non-concentrated groups to identify the effect of cell density during cryopreservation. After 12 months of storage, the samples were again divided into centrifugation and non-centrifugation groups to learn the effect of $Me_2SO$ on the culture. Viability and growth of the microalgae were not influenced by cell density or the centrifugal removal of the $Me_2SO$ after thawing.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.101-106
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• 1992

Vie investigated the clarification effects of foxtail millet wine, a traditional wine in Cheju island, by centrifugation, protease treatment and ultrafiltration(UF). It was difficult to remove completely cloudy substances in foxtail millet wine only by centrifugation. With protease concentration of $5{\times}10^{-4}%(w/v)\;at\;35^{\circ}C$, for 2 hrs, foxtail millet wine was clarified effectively. Papain and bromelain appeared similar effects to the clarification of wine, but ficin was inferior to those. Ultrafiltration with pore size $100K\;and\;0.22{\mu}m$ membranes had appeared better clarification effects than the best result of enzyme treatment, and then was considered as a simple and economic method.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.157-162
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• 2007

Lactic acid bacteria (LAB) has been regarded as a useful microorganism and tried to manipulate plasmid DNA for increasing the usefulness. Although several methods have been developed to isolate plasmid DNA from Escherichia coli (E. coli), these methods were not sufficient to apply to LAB with exception of O'Sullivan's lysis method. So, we evaluated plasmid DNA extraction from LAB using general E. coli preparation methods and tried to improve the extraction yield and DNA purity by modifying O'Sullivan's alkaline lysis method. To improve the extraction yield, salt and carrier were added to precipitant and those were incubated at $-70{^{\circ}C}$. Only incubation at $-70{^{\circ}C}$ was the effective method of those modifications. Purity of plasmid DNA was improved by two times of each centrifugation and phenol/chloroform extraction. However, DNA was damaged by twice extraction with phenol/chloroform. Also, exclusion of ethidium bromide showed negative effect to purity. Additionally, it was recommended that improvement of the extraction yield may be due to centrifugation at high speed for more time and to dissolving complete DNA pellet before addition of 7.5 M ammonium acetate. Extraction using this modification produced higher quality of plasmid DNA.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.384-388
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• 1996

Volatile flavor compounds of a sea tangle powder and two kinds of extract were analyzed by GC/MS. Extract I was prepared by boiling for 2 hours and centrifugation, while extract II by a sequential procedure of enzymatic hydrolysis, boiling in 1.5% NaCl solution. centrifugation and ultrafiltration to remove viscous materials. Fifty six volatile compounds from the dried sea tangle powder and the extracts were identified. The GC profiles of the extract II were different from those of the dried powder and the extract 1, indicating most volatile compounds were lost during removing viscous materials. Particularly those compounds in the initial and later parts of the GC profiles were significantly decreased and some of the compounds such as fatty acids. 3,5-nonadien-2-ol and 1-penton-3-ol were not detected.

• Journal of agricultural medicine and community health
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• v.17 no.1
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• pp.46-55
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• 1992

A systematic study was conducted to identify and isolate a serologically pertinent antigen with high specific activity and low cross reactivity from P.westermani antigen. Differential centrifugation of the homogenate yield three particulate and one soluble fractions ; the $480{\times}G$ pellet(Pw1), the $7650{\times}G$ pellet(Pw2) treated with n-butanol(Pw3), and $100000{\times}G$ supernatnat(Pw4). Comparison of antigenicity of these antigens, based upon differential centrifugation, to that of saline extract of P. westermani worm(SEP) was performed by SDS-PAGE and immunoblot techniques. The results obtained were as follows : 1) The ratio of absorbance value of ELISA against paragonimiasis positive pool sera to that of negative sera was highest when using Pw3 as antigen and that was lowest using Pwl. 2) Silver stained and SDS-PAGE of each antigen showed 34 and 13Kd band as common antigen band, but Pw2 didn't show clear band. 3) By immunoblot 55 and 34Kd bands using SEP and Pw4 showed strong positive reaction without cross reaction with sera from other helmenthic infections. Using Pw3, 10Kd band was observed as specific band. In conclusion, Pw3($100000{\times}G$ pellet urea soluble, treated with n-butanol) and Pw4($100000{\times}G$ supernatant) were usable for ELISA and immunoblot technique.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.611-618
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• 2007

We demonstrate the sol-gel coating technique of colloidal clusters for producing hollow micro-particles with complex morphologies. Cross-linked amidine polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion copolymerization of styrene and divinylbenzene. The amidine PS particles were self-organized inside toluene-in-water emulsion droplets to produce large quantities of colloidally stable clusters. These clusters were coated with thin silica shell by sol-gel reaction of tetraethylorthosilicate (TEOS) and ammonia, and the organic polystyrene cores were removed by calcination at high temperature to generate nonspherical hollow micro-particles with complex morphologies. This process can be used to prepare hollow particles with shapes such as doublets, tetrahedra, icosahedra, and others.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.11 no.1
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• pp.21-31
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• 1985

The effect of dispersed phase on the stability of emulsion system with polyoxyethylene dodecyl ethers and their variation of ethylene oxide moles was studied by such methods as interfacial tension measurement, centrifugation and droplet size variation with time. The experiments showed that, in interfacial tension measurement, long chain alkanols into dispersed phaes are more effectively adsorbed onto interface, while long chain alkanes nearly not, and in centrifugation, dispersed phase with alkanols is less separated than that with alkanes. On the other hand, alkanes help more stabilyzing emulsion than alkanols in droplet size variation. And the addition of NaCl or Urea, and variation of E.O. moles have very slight effects on the stability with alkanes than with alkanols. Moreover, the longer carbon chain length is, dispersed phase is more effective on emulsion stability. Supposed from these facts is that more stable emulsion can be made with alkanes which retard molecular diffusion by water solubility decrease rather than alkanols which raise resistance to coalescence by rigid interfacial mixed monolayers formation. In conclusion, the stabilities of these emulsions are proved to be more influenced by molecular diffusion than coalescence.