• Parasites, Hosts and Diseases
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• v.32 no.4
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• pp.243-248
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• 1994

Plasma membrane proteins of a Korean isolate of Trichomonus vofinalis HY-1 were fractionated for antigen analysis. Homogenates of T. vaginalis were fractionated by the differential centrifugation using sucrose step-gradient method. The interface layer from the 25%/45% sucrose was collected as a plasma membrane fraction and its purity was examined by transmission electron microscopy. The antigenicity of plasma membrane fraction was analysed by enzyme-linked immunoelectrotransfer blot technique with immune rabbit serum and compared with surface antigen labelled with N. hydroxysuccinimide-biotin. The fluffy fraction of 25%/45% sucrose interface was homogeneous and membrane particles were present as extended sheet and concentric vesicles showing typical trilamellar appearance under transmission electron microscope. Seven fractions at 40, 50, 60, 110, 130, 140 and 150 kDa were identified as the antigenic membrane proteins in EITB with anti HY-1 rabbit serum. The common band at 60 kDa was detected both in antigenic fractions of plasma membrane and surface protein labelled with NHS-biotin. This result indicates that this protein is considered as a major surface antigen of T. vaginalis. The role of this surface antigen at 60 kDa should be studied further.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.33-39
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• 1989

Pure separation of various leukocytes is required for the assessment of their roles in immunological and phisiological function. In this study, pure separation of monocytes from canine peripheral blood was attempted. At first, mononuclear cells (PBMC) were separated by ficoll-hypaque gradient method and then monocytes were recovered from PBMC suspensions in sucrose gradient Sol. (PBMC-Sucrose), autologous plasma (PBMC-Plasma) and autologous serum (PBMC-Serum) incubated at $37^{\circ}C$ for 2 hours. 1. In the separation of PBMC by ficoll-hypaque gradient method in canine blood, higher relative centrifugal force (RCF) was required, as high as more than 1,300xg RCF for 40 minutes, for clear formation of PBMC layer than that in human blood as usually used 400xg RCF for 40 minutes. 2. In monocytes-separation from three PBMC suspensions following PBMC separation, recovery-, purity- and viability-rate of monocytes showed better results in PBMC-Plasma and PBMC-Serum than in PBMC-Sucrose suspension, particulary showing better results from PBMC suspensions performed by centrifugation at 1,500xg RCF for 40 minutes.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.107-114
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• 1996

본 연구는 인간면역결핍바이러스의 입자를 비이온성 계면활성제로 처리할 때 바이러스 입자구조에서 분리되어 방출되는 바이러스 구조단백질들의 분포를 sucrose gradient로 분석하여, 바이러스 입자를 구성하는 바이러스 구조단백질과 바이러스입자의 생물리학적 특성을 연구하였다. 바이러스입자들을 0.16% NP40 (Nonidet P-40)으로 처리할 때, 바이러스 capsid 단백질과 바이러스 막 단백질 (membrance protein)들은 다른 바이러스 구성성분들과 잘 분리되었다. 계면활성제처리에서 방출되지 않은 구성 성분들은 matrix 단백질, nucleocapsid 단백질, reverse transcriptase, integrase 및 바이러스 RNA genome로써, 이들은 subviral 구조를 형성한다. 이러한 결과는 상대적으로 다른 바이러스들의 capsid 단백질과 면역 결핍 바이러스의 capsid 단백질 (p24)를 비교할 때, 면역결핍바이러스의 capsid 단백질은 바이러스핵을 형성할 때, capsid 단백질 사이의 결합력이 매우 약한 것으로 추정된다. 또한 바이러스 조절단백질의 하나인 vpr 단백질을 함유하는 바이러스입자를 NP40 처리하여 분석하였을 때, vpr 단백질은 subviral 구조에 존재하는 것으로 나타났다.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.219-224
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• 1987

A strain of Leptospira interrogans(UM-19) was isolated in 1984 from a patient with epidemic pulmonary hemorrhagic fever. The bacteria has been characterized morphologically by a polymorphism showing spiral forms, short and long rods in culture. In order to study the biological relatedness among these forms of the bacteria, the short rods were separated from others by means of continuous sucrose density gradient centrifugation, and cultured at various temperatures such as $10^{\circ}C$, $15^{\circ}C$, $30^{\circ}C$ and $37^{\circ}C$. It was revealed that cultivation or subcultivation of the short rods has resulted in morphological changes observed by darkfield examination, silver stain, and scanning electron microscope showing spiral forms as well as short and long rods.

• ALGAE
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• v.28 no.1
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• pp.121-129
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• 2013

Intact phycobilisomes from a wild-type red Chondrus crispus and its vegetatively derived green mutant were isolated by centrifugation through a discontinuous sucrose density gradient. Pigment composition was subsequently characterized by spectrophotometry. Vegetative thalli of the two strains grown together for six months in the laboratory resulted in different pigment profiles. Two pigmented phycobilisome bands appeared in the sucrose gradient of the wild-type alga, a purple coloured one, and a pink one, whereas only a single blue band appeared in the gradient of the green mutant. Spectrophotometric and fluorescence analyses identified the phycobiliprotein composition of the purple band as the typical phycoerythrin-phycocyanin-allophycocyanin complement in the wild-type, but there was no detectable phycoerythrin present in the blue band of the green mutant. Sodium dodecyl sulphate, preparative polyacrylamide gel electrophoresis analysis confirmed the presence of allophycocyanin subunits in all extracts, but firm evidence of an R-phycoerythrin linker polypeptide in the blue band was missing. These results highlight the ability of C. crispus to adapt to a phycoerythrin deficiency by adjusting light harvesting pigment ratios.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.206.1-206
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• 2000

No Abstract, See Full Text

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.30-36
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• 2012

The active fraction of soil organic matter, which includes organic debris and light organic fraction, plays a major role in nutrient cycling. In addition, particulate organic matter is a valuable index of labile soil organic matter and can reflect differences in various soil behaviors. Since soil organic matter bound to soil mineral particles has its density lower than soil minerals, we partitioned soil organic matter into debris ($<1.5g\;cm^{-3}$), light fraction ($1.5-2.0g\;cm^{-3}$), and heavy fraction ($>2.0g\;cm^{-3}$), based on high density $ZnCl_{2-}$ sucrose solutions. Generally, partitioned organic bands were clearly separated, demonstrating that the $ZnCl_{2-}$ sucrose solutions are useful for such a density gradient centrifugation. The available gradient ranges from 1.2 to $2.0g\;cm^{-3}$. Although there was not a statistically meaningful difference in organic debris and organomineral fractions among the examined soils, there was a general trend that a higher content of organic debris resulted in a higher proportion of light organomineral fraction. In addition, high clay content was associated with increased fraction of light organomineals. Partitioning of soil organic carbon revealed that carbon content is reduced in the heavy fraction than in the light fraction, reflecting that the light fraction contains more fresh and abundant carbon than the passive resistant fraction. It was also found that carbon contents in the overall organic matter, debris, light fraction, and heavy fractions may differ considerably in response to different farming practices.

• Journal of Korean society of Dental Hygiene
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• v.17 no.3
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• pp.381-394
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• 2017

Objectives: This study aims to evaluate carbonated drinks induced dental caries with qualitative analysis and to compare with oral organic acids including lactate, acetate, propionate, formate, butyrate, pyruvate and valerate which cause caries when taking either 10% sucrose drinks or carbonated drinks. Methods: Saliva was collected from six study subjects before and after (start, 5, 10, 30 minutes) taking water intake upon (A) 10% sucrose intake, (B) 10% sucrose intake, and (C) carbonated drink intake, then they were centrifuged at 1,200 rpm followed by removing bacteria and enzymes with syringe filtering, performing a qualitative analysis with HPLC conductivity detection (GP50 gradient pump, ED 50 detector) after saliva pre-treatment under isocratic 100 mM NaOH mobile phase. Results: Higher risk of dental caries was evaluated in order of C>B>A, with the results of total oral organic acids' concentration, lactates of organic acids and organic acids produced after 5 minutes from the 3 types of drinks intake. Conclusions: Carbonated beverages were estimated to develop higher dental caries induction than beverages containing 10% sucrose because of the high organic acid concentration in the mouth after its intake.

• KSBB Journal
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• v.16 no.5
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• pp.523-525
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• 2001

Curdlan is one biopolymer composed of ${\beta}$1,3-glucan and dissolved in a alkali solution but formed salt under neutral or acid condition. It was produced by Agrobactrium species and the separation process is necessary to make pure curdlan from the culture broth. The pH swing separation method was as feasible separation process using solubility changes with the pH difference. however, this method requires a lot of acid and alkali solution also produces a lot of waste. Therefore, an efficient process which could save energy and minimize toxic waste was developed. A density gradient separation process was developed in this research. High density sucrose solution was used as a separation agent. Curdlan was separated from the culture broth when the density of the sucrose solution was 1.15 g/L. Since the curdlan was produced on the surface of cell wall. the pre-treatment of culture broth was necessary. Curdlan recovery yield was increased up to 83% with the homogenization of the culture broth and further increased up to 87% with the treatment of alkai-acid solution.

• The Journal of the Korean Society for Microbiology
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• v.34 no.5
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• pp.423-433
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• 1999

A novel bacteriophage, designated as VPP97, that infects the strains of Vibiro parahaemolyticus (hallophilic, Gram-negative bacterium) isolated most commonly from marine environments, has been discovered, and several of its properties have been determined. The plaques were clear and sized $0.6{\sim}1.0\;mm$ in diameter. The virion forms a single band on 70% sucrose gradient and ${\rho}1.50$ CsCl gradient by sucrose gradient centrifugation and CsCl gradient centrifugation respectively. It has a hexagonal head and a relatively long tail, as shown by electron microscopy. Vibrio alginolyticus, Vibrio fluvialis and Vibrio furnissii were also sensitive to this phage. It was almost totally inactivated at $70^{\circ}C$ and at pH below 5 or over 10. The nucleic acid of VPP97 is composed of DNA. The VPP97 had 9 specific structural proteins sized between 21.5 kDa and 97.4 kDa on SDS-PAGE. When V. parahaemolyticus cultures were treated with either phage VPP97 or one of the several antibiotics for 2 hours, the viable number of V. parahaemolyticus treated with the phage VPP97 is lower than that treated with chloramphenicol, erythromycin or penicillin, but not lower than that treated with tetracycline. Mice that have responded to the phage treatment revealed the lower numbers of V. parahaemolyticus in small intestine and less damage on small intestine compared to the untreated mice. Therefore, we suggest that the phage treatment appears effective to the infection by V. parahaemolyticus.