Biomedical subjects

S O Chung

Publications and source records attributed to S O Chung.

At least 19 recordsLinked to original sources

PubMed2000

Asitrilobins C and D: two new cytotoxic mono-tetrahydrofuran annonaceous acetogenins from Asimina triloba seeds.

Two new bioactive mono-tetrahydrofuran (THF) gamma-lactone acetogenins, asitrilobins C (1) and D (2), were isolated from the seeds of Asimina triloba (Annonaceae) by directing the fractionation with brine shrimp lethality. Compounds 1 and 2 have a relative stereochemical relationship of threo/trans/threo across the mono-THF ring with its two flanking hydroxyls. Their structures were established on the basis of chemical and spectral evidence. Compounds 1 and 2 showed selective cytotoxicity comparable with adriamycin for the breast carcinoma (MCF-7) and the colon adenocarcinoma (HT-29) cell lines.

4-Butyrolactone↗

PubMed1999

cis-Annonacin and (2,4)-cis-and trans-isoannonacins: cytotoxic monotetrahydrofuran annonaceous acetogenins from the seeds of Annona cherimolia.

cis-Annonacin (1) and the mixture of (2,4)-cis-and trans-isoannonacins (2 and 3), three known mono-tetrahydrofuran annonaceous acetogenins, have been isolated from the seeds of Annona cherimolia by the use of the brine shrimp lethality test (BST) for bioactivity directed fractionation. Their structures were elucidated based on spectroscopic and chemical methods. 1 showed potent cytotoxicities in the brine shrimp lethality test (BST) and among six human solid tumor cell lines with notable selectivity for the pancreatic cell line (PaCa-2) at about 1,000 times the potency of adriamycin. The mixture of 2 and 3 is over 10,000 times cytotoxic as adriamycin in the pancreatic cell line (PaCa-2). All of the compounds are about 10 to 100 times as cytotoxic as adriamycin in the prostate cell line (PC-3).

Animals↗

PubMed1996

Genomic organization of purK and purE in Brevibacterium ammoniagenes ATCC 6872: purE locus provides a clue for genomic evolution.

From the genomic library of Brevibacterium ammoniagenes ATCC6872, the purE locus encoding 5'-phosphoribosyl-5-aminoimidazole (AIR) carboxylase (EC 4.1.1.21) was cloned and its nucleotide sequence was determined. From the sequence analysis, two distinct open reading frames (ORFs) in the sequence of the purE locus were identified as purK and purE genes (purK-purE). An in vivo translation experiment reconfirmed the purK and purE genes to be independent. The genomic organization in the purE locus of B. ammoniagenes is opposite to that of the bacteria Escherichia coli and Bacillus subtilis. However, it coincides with the fused genes (purKE) of higher organisms Saccharomyces cerevisiae, Schizosaccharomyces pombe and Vigna aconitifolia. This suggests that the purE locus might be an intermediate form for genomic evolution of bacteria to higher organisms.

Amino Acid Sequence↗

PubMed1995

Molecular cloning and sequencing of arylphorin-binding protein in protein granules of the Sarcophaga fat body. Implications of a post-translational processing mechanism.

Previously, we identified an arylphorin-binding protein of Sarcophaga peregrina (flesh fly) with a molecular mass of 120 kDa and suggested its participation in the selective uptake of arylphorin from the hemolymph into the pupal fat body at metamorphosis (Ueno, K., and Natori, S. (1984) J. Biol. Chem. 259, 12107-12111). This paper reports the isolation and sequencing of cDNA for the 120-kDa protein. This protein consists of 1146 amino acid residues. Immunoblotting and RNA blotting experiments revealed that this protein is present as two fragments of 76 kDa (695 residues) and 53 kDa (451 residues) in the larval fat body. When larvae pupate, the 120-kDa protein gene is further activated and the complete 120-kDa protein is synthesized without fragmentation. This suggests a novel mechanism for the production of the 120-kDa protein regulated by a proteinase depending upon the stage of development of Sarcophaga. All of these proteins were found to be localized in protein granules in the adipocytes.

Amino Acid Sequence↗

PubMed1978

Single-day treatment of trichomonas vaginitis with low dose of ornidazole.

A total of 107 cases of trichomonas vaginitis were treated with different regimens of ornidazole. The overall success rate of the treatment assessed by wet smear and clinical signs after three days in 68 cases was 98.5%. The side effects were mild and of short duration. These were noted in 14.7% of the assessable cases. No significant differences were seen in the success rate between the three drug regimens and the preliminary conclusions of the trial are that ornidazole is safe and effective in the treatment of trichomonas vaginitis in Korean women with an oral dose of 1.0 gm, 1.0 gm plus 0.5 gm intravaginally or 2.0 gm given in a single day.

Adult↗

PubMed1977