• 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.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.128-134
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• 1989

$Na^+-Ca^{2+}$ exchange process in sarcolemmal vesicles isolated from mesenteric arteries of Wistar-Kyoto normotensive(WKY) and spontaneously hypertensive rats(SHR) was investigated. The sarcolemmal fractions isolated after homogenization and sucrose density gradient centrifugation were enriched with 5'-nucleotidase and ouabain sensitive, $K^+-dependent$ phosphatase activities. When the vesicles were loaded with $Na^+$, a time dependent $Ca^{2+}$ uptake was observed. However, very little $Ca^{2+}$ uptake was observed when the vesicles were loaded with $K^+$, or $Ca^{2+}$ uptake of the $Na^+-loaded$ vesicles was carried out in high sodium medium so that there was no sodium gradient. When the vesicles loaded with $Ca^{2+}$ by $Na^+-Ca^{2+}$ exchange were diluted into potassium medium containing EGTA, $Ca^{2+}$ was rapidly released from the vesicles. $Na^+-dependent\;Ca^{2+}$ uptake was increased in SHR compared to WKY, but passive efflux of preaccumulated $Ca^{2+}$ from the vesicles was decreased in SHR. The data indicate that the membrane vesicles of rat mesenteric arteries exhibit $Na^+-Ca^{2+}$ exchange activity. It is also suggested that changes of this process in vascular smooth muscle cell membrane of SHR may be involved in higher intracellular $Ca^{2+}$ concentration and higher basal tone in SHR.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.51-57
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• 1992

Mitochondria in Pleurotus ostreatus were isolated and purified by stepped sucrose density gradient centrifugation, to compare the effects of organic compound on the activities of mitochondrial ATPase in Basidiomycotina with those in mammalian cell. The effects of N, N'-dicycio-hexylcarbodiimide (DCCD), carbonyl cyanide m-chlorophenylhydrazone (CCCP), sodium azide and aurovertin known as compounds to be related to electron transfer system in mitochondria were studied. A activity of mitochondrial ATPase was inhibited by 64%, 57% and 53% in the presence of 0.25 mM DCCD, 0.02 mM sodium azide and 1.5 $({\mu}g/mg\;of\;protein)$ aurovertin B, respectively. It was stimulated by 22% in the presence of 0.15 ${\mu}M$ CCCP.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.182-186
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• 1996

국내에서 재배되고 있는 고추(Capsicum annuum L.)로부터 분리된 TMV pepper 계통을 density gradient centrifugation을 이용하여 순화하였다. 이로부터 바이러스의 total RNA를 분리하였고 RT-PCR에 의하여 TMV pepper 계통의 외피단백질 cDNA를 합성, 증폭하였으며 이를 pBluescript II SK- 벡터에 재조합하였다. 본 실험에서 바이러스 외피단백질과 3` non-coding region을 포함하는 재조합 클론 p1561과 p1562로부터 염기서열을 분석하였고 그 결과로 477 염기의 외피단백질 유전자를 포함하는 691 염기가 합성되었음을 확인하였으며 이것과 TMV common 계통으로부터 합성된 외피단백질 cDNA와의 최대 유사도는 69%였다. 또한 유추된 아미노산 서열에서 이들 두 계통간의 최대 유사도는 81%였다.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.86-93
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• 1991

cis-Diamminedichloroplatinum(II)(CDDP), an antitumor drug, did not generate crosslink between bluetongue virus (BTV) capsid protein at moderate concentration. Cesium chloride density gradient centrifugation study revealed that protein-RNA crosslink was not detectable in CDDP treated BTV. CDDP treated BTV ds RNA showed remarkable change in the migration pattern in polyacrylamide gel electrophoresis. These results suggest that the reduction of BTV core associated transcriptase activity is most likely by the CDDP adduction to the genomic ds RNA rather than by the protein-RNA crosslink and/or protein-protein cross-link.

• Journal of Sericultural and Entomological Science
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• v.19 no.1
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• pp.25-32
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• 1977

The flacherie (FV) and Ina-flacherie (Ina-FV, named arbitarily) viruses of the silkworm, Bombyx mori was isolated from infectious larvae. Two types of infectious particles were purified by sucrose density gradient centrifugation. Some properties of the purified particles were investigated. Electron micrographs showed that FV and Ina-FV were spherical particles with diameters of 27nm and 20nm, respectively. The sedimentation coefficient of Ina-FV was 80S.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.101-106
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• 1996

Tobacco mosaic virus (TMV) tomato strain was isolated from tomato "Seo-Kwang" in Korea. The virion was purified by density gradient centrifugation, and total viral RNA was isolated from the purified particles. Coat protein (CP) cDNA of the virus was synthesized by RT-PCR, and the purified cDNA fragment was subcloned to pBluescript II SK-. The analysis of nucleotide sequence showed that this cDNA was 693 nucleotides long from the insert of clone p1571 and p1572 which contain complete codons of the viral coat protein gene (474 nucleotides) and 3' untranslated region. The nucleotides of coat protein encoding cDNA of the strain were 6 nucleotides less than that of TMV common strain isolated from tobacco plant in Korea. The CP gene showed 70% maximum homology with that of the common strain in the nucleotide level and 86% maximum homology in amino acid level.cid level.

• Korean Journal of Microbiology
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• v.25 no.4
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• pp.255-261
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• 1987

Five independent Actinomycetes harboring plasmids were isolated from soil. Molecular weight of these plasmids was 55kb, 6.2kb, 4.4kb, 55kb and 7.0kb, respectively. Among them small and apprent high copy number plasmids, pJY501 of 4.4kb and pHY711 of 7.0kb, were selected. The plasmids purified by CsCl-EtBr density gradient centrifugation preserved the conformation of supercoiled covalently closed circular molecule, and an apparent copy number was estivated about 150 and about 35 per chromosome. The isolates carrying plasmids were assigned to the genus Streptomyces. For the purpose of introducing selection markers into the isolated plasmids, the tsr fragmemt of pIJ702 was inserted into the BclI site of pJY 501 and pJY711. And the recombinant plasmids constructed designated as pJY502 and pJY712 respectively.

• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.61-65
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• 2011

The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on motile sperm recovery rate and motion kinematics. Frozen semen samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk-Tris-glycerol extender) were thawed in $37^{\circ}C$ water bath for 1 min. After thawing, the mixed semen samples were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities ($300{\times}g$ and $700{\times}g$) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Motile sperm recovery rate and motion kinematics were evaluated by computer assisted sperm analyzer using Makler counting chamber. Sperm motility (%) and motile sperm recovery rate showed similar pattern in all treatment groups. However, sperm motility (%) and motile sperm recovery rate were highest at $700{\times}g$ for 30 min through a discontionous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll. There were no significant differences in motion kinematics after various Percoll washings. These results suggest that force of centrifugation, centrifugation time, and Percoll volume significantly affect motile sperm recovery rate.

• Korean journal of applied entomology
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• v.17 no.3 s.36
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• pp.131-138
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• 1978

A virus named Cymbidium mild mosaic virus(Cy MMV), was mechanically transmitted to Chenopodium amaranticolor from the leaves of Cymbidium with mild mosaic symptoms. The virus was cultured in C. amaranticolor, in which it produced local chlorotic and ring spots, followed by systemic vein clearing with distortion. CyMMV infected 7 out of 35 species of plants. In C. amaranticolor juice infectivity was lost by heating at $90^{\circ}C$ for 10 miuntes, and by aging at$20^{\circ}C$ for 60 days, and by diluting at $10^{-6}$ when bioassayed on C. amaranticolor. CyMMV was not transmitted by Myzus persicae. The virus was purified after clarification of homogenized C. amaranticolor leaf tissues with chloroform, by differential centrifugation followed by sucrose density gradient centrifugation. Electron microscopic examination of purified preparation showed spherical particles of 28nm in diameter. The UV absorption spectrum of purified preparation was typical of u nucleoprotein (max. at 261nm. min. at 243nm), and showed 260/280=1.72 and max/min=1.26. The value of the sedimentation coefficient of the virus was S20.w=126. In gel-diffusion tests, CyMMV antiserum reacted with CarMV, but not with any of four other viruses (BBWV, CRSV, CMV, TBRV) having similar particles and properties in vitro. In ultra-thin sections of CyMMV infected tissues, a large number of virus particles were found in the cytoplasm of mesophyll cells and in xylem vessels.