• ALGAE
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• 제30권4호
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• pp.275-280
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• 2015

Coolia santacroce is a newly described epibenthic dinoflagellate species collected from the U.S. Virgin Islands. The original description indicates this species is unique from others in the Coolia monotis complex due to the relative size of the apical pore complex, broad range of pore sizes, and ribosomal DNA. The original description was done based on the isolation and cultivation of one isolate of the organism. In this study, we report three more isolates of Coolia santacroce collected from the Bahamas. Morphological observations were made using scanning electron microscopy that do not correspond to those from the original description, indicating the variability of the morphological features. However, analysis of the D1 / D2 regions of the large subunit rDNA places the three strains in a strongly supported monophyletic clade with the type specimen.

• Parasites, Hosts and Diseases
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• 제40권1호
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• pp.25-31
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• 2002

We describe a riboprinting scheme for identification of unknown Acanthamoeba isolates at the species level. It involved the use of PCR-RFLP of small subunit ribosomal RNA gene (riboprint) of 24 reference strains by 4 kinds of restriction enzymes. Seven strains in morphological group I and III were identified at species level with their unique sizes of PCR product and riboprint type by Rsa 1. Unique RFCP of 17 strains in group II by Dde I. Taq I and Hae III were classified into: (1) four taxa that were identifiable at the species level. (2) a subgroup of 4 taxa and a pair of 2 taxi that were identical with each other. and (3) a species complex of 7 taxa assigned to A. castellanii complex that were closely related. These results were consistent with those obtained by 18s rDNA sequence analysis. This approach provides an alternative to the rDNA sequencing for rapid identification of a new clinical isolate or a large number of environmental isolates of Acanthamoeba.

• 한국자기공명학회논문지
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• 제2권1호
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• pp.33-40
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• 1998

The cross peak intensities versus mixing times of 2D NOESY spectrum for a corepressor L-trp were simulated for the case of a ligand exchanging between free (AX) and bound (A'X') forms in protein/DNA complex. The direct NOE (I(AX)) of the free ligand exhibited a small positive intensity indicative of the strong dominant influence of the bound ligand. The exchange-mediated NOE peak (I(AX')) was very sensitive to corepressor exchange. However, both diagonal (I(A'A')) and direct NOE (I(A'X')) intensities of the bound ligand were not affected much at initial stage. Both peaks were severely influenced by exchange at mixing times of greater than 100 ms. In conclusion, since the NOE intensity is a function of exchange rate, the exchange effect should be considered to properly extract accurate distance information for bound ligand in the presence of conformational exchange.

• Journal of Plant Biology
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• 제11권1호
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• pp.15-21
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• 1968

Chlorella ellipsoidea were grown in a Mg-free medium. Aliquots of the algal cell were taken out at the beginning and predetermined time intervals during the culture and were analyzed the contents of phosphate in various fractions of the cell constituents. The results obtained were compared with those of the control. When Chlorella cells were grown in a Mg-free medium, the contents of phosphate in the DNA protein, RNA-olyphosphate complex, nucleotidic-lbileP, and PCA-soluble, fractions decreased compared with those of the control, while the content of acid insoluble polyphosphate increased significantly. On the otherhand, RNA-P and lipid-P showed the tendency of decrease at the early stage of the culture, but they were increased more than those in the control as culture proceeds. It is showed that phosphate turnover from acid-insoluble polyphosphate into DNA, protein, and RNA-polyphosphate complex was inhibited by magnesium-deficiency of the cells.

• BMB Reports
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• 제36권3호
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• pp.305-311
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• 2003

A modified actinomycin D was prepared with a hydroxyl group that replaced the amino group at the chromophore 2-position, a substitution known to strongly reduce affinity for double-stranded DNA. Interactions of the modified drug on single-stranded DNAs of the defined sequence were investigated. Competition assays showed that 2-hydroxyactinomycin D has low affinity for two oligonucleotides that have high affinities ($K_a\;=\;5-10{\times}10^6\;M^{-1}$ oligomer) for 7-aminoactinomycin D and actinomycin D. Primer extension inhibition assays performed on several single-stranded DNA templates totaling around 1000 nt in length detected a single high affinity site for 2-hydroxyactinomycin D, while many high affinity binding sites of unmodified actinomycin D were found on the same templates. The sequence selectivity of 2-hydroxyactinomycin D binding is unusually high and approximates the selectivity of restriction endonucleases. Binding appears to require a complex structure, including residues well removed from the polymerase pause site.

• BMB Reports
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• 제30권6호
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• pp.421-425
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• 1997

The 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT) has been used as intercalating DNA binding drugs in the photo-chemotherapy of skin diseases. The conformation and stability of DNA octamer duplex, $d(GGGTACCC)_2$, cross-linked with AMT has been studied by NMR spectroscopy. All the proton resonances of the psoralen cross-linked octamer were assigned and meting temperature studies were carried out based on the assignment of the proton resonances. The aromatic proton chemical shift data suggest that the conformation of the helix cross-linked with psoralen is destabilized more to furanside of the psoralen. possibly due to the protrusion of the aminomethyl side chain of the psoralen.

• 한국환경성돌연변이발암원학회지
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• 제25권2호
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• pp.71-75
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• 2005

Green tea and their major constituents such as catechins are famous materials for their anti-oxidative and anti-carcinogenic activity, but many compounds with reducing power can promote the oxidation in their oxidized form or in the presence of metal ion. We investigated the pro-oxidative effect of the ethanol extract equivalent up to 30mg of dried weight of green tea leaves in four in vitro systems which could be used for detecting DNA damage. Although ethanol extract of green tea did not show significant mutagenicity in Salmonella typhimurium TA102, which is sensitive strain to oxidative stress, it degraded deoxyribose extensively in the presence of $FeCl_3-EDTA$ complex, promoted 8-oxoguanine formation in the live bacteria cell, Salmonella typhimurium TAI04, and cleaved super coiled DNA strand with the help of copper ion. It suggested that green tea, famous anti-oxidative material, can be pro-oxidant according to the condition of extraction or metal existence.

• 생물정신의학
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• 제15권4호
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• pp.243-253
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• 2008

In the post-genomic era, the mechanisms controlling activation of genes are thought to be more important. Gene-environment interactions are crucial in both development and treatment of psychiatric disorders as they are complex genetic disorders. Epigenetics is defined as a change of gene expression that occurs without a change of DNA sequence and can be heritable by certain mechanisms. Epigenetic changes play essential roles in control of gene activation. DNA methylation, chromatin remodeling and RNAi act as key mechanisms for epigenetic modifications of genes. Here, we review the basic mechanisms of epigenetics and discuss their potential involvement of human diseases, including psychiatric disorders.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1211-1216
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• 2004

The interaction of the antitumour agent doxorubicin with calf thymus DNA is investigated in an aqueous solution at a pH level of 6-7 with molar ratios of 1/10. A UV-resonance Raman spectroscopy and surface enhanced Raman spectroscopy are used to determine the doxorubicin binding sites and the structural variations of doxorubicin-DNA complexes in an aqueous solution. Doxorubicin intercalates with adenine and guanine via a hydrogen bond formation between the N7 positions of purine bases and the hydroxyl group of doxorubicin.

• Journal of Microbiology
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• 제38권2호
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• pp.113-116
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• 2000

Escherichia coli F plasmid partition apparatus is composed of two trans-acting proteins (SopA and SopB) and one cis-acting DNA sequence (sopC). The SopB-sopC complex has been suggested to serve a centromere-like function through its interaction with chromosomally encoded proteins which remain to be identified. In this paper, we are introducing a new yeast 1.5-hybrid system which assembles the two-hybrid and one-hybrid system as a mean to find and additional component of the F plasmid partition system, interacting with DNA (sopC)-bound SopB protein. The results indicates that this system is a promising one, capable of selecting an interacting component.