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Biomedical subjects

J Uzawa

Publications and source records attributed to J Uzawa.

At least 19 recordsLinked to original sources
PubMed2001

A new phosphoglycerolipid, 'phosphatidylglucose', found in human cord red cells by multi-reactive monoclonal anti-i cold agglutinin, mAb GL-1/GL-2.

Cord red cell membranes express many differentiation-related molecules. To study such molecules, we have established human cell lines, termed GL-1 and GL-2, by the Epstein-Barr virus transformation method, both of which produce monoclonal anti-i cold agglutinin [Y. Nagatsuka et al., Immunol. Lett. 46 (1995) 93-100]. Thin layer chromatography immunoblotting analysis revealed that these antibodies had broad specificities reacting with a variety of glycolipid antigens. Of the immunoreactive lipid antigens, a new phosphoglycerolipid containing glucose from human cord red cells was found. The isolated lipid was unstable to alkaline hydrolysis and contained glucose as a sole sugar. Secondary ion mass spectrum-collision-induced dissociation mass spectrometric analysis of this lipid gave the main molecular ion peak at m/z 885 corresponding to phosphatidylhexose. This antigen was susceptible to phospholipases A2, C and D but resistant to phosphatidylinositol-specific phospholipase C. Two-dimensional nuclear magnetic resonance spectroscopy confirmed that glucose is linked to the sn-glycerol 3-phosphate residue with a beta-anomeric configuration. Based upon these combined results, we identified this lipid as phosphatidyl-beta-D-glucose. This is the first report showing the presence of the glucosylated glycerophospholipid in mammalian sources.

Agglutinins↗
PubMed2000

Three new triterpenoid saponins from the seeds of Vaccaria segetalis.

Three new triterpenoid saponins, named segetoside G(1), H(2) and I(3), have been isolated from the seeds of Vaccaria segetalis. On the basis of chemical reaction and spectral data, their structures have been established as: 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-arabinofuranosyl (1-->3)]-beta-D-(4-O-acetyl)-fucopyranosyl-gypsogenin-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-(6-O-butyl ester)-glucuronopyranoside (1), 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-(5-O-acetyl)-arabinofuranosyl-(1-->3)]-beta-D-(4-O-acetyl)-fucopyranosyl-gypsogenin-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranoside (2) and 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-(5-O-acetyl)-arabinofuranosyl-(1-->3)]-beta-D-(4-O-acetyl)-fucopyranosyl-quillaic acid-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranoside (3).

China↗
PubMed2000

Nematicidal alkaloids and related compounds produced by the fungus Penicillium cf. simplicissimum.

A new nematicidal alkaloid, peniprequinolone (1), together with the known alkaloids penigequinolones A and B (2a, 2b), 3-methoxy-4-hydroxy-4-(4'-methoxyphenyl)quinolinone (3), and 3-methoxy-4,6-dihydroxy-4-(4'-methoxyphenyl)quinolinone (4), were isolated from Penicillium cf. simplicissimum (Oudemans) Thom. Cyclopenin (5) and a compound (6a/6b) structurally related to cyclopenin also were isolated from the fungus, and their structures were established by spectroscopic analysis. The biological activities of 1, 2, 3, 4, and 5 were examined by a bioassay with root-lesion nematodes.

Alkaloids↗
PubMed2000

Haematocin, a new antifungal diketopiperazine produced by Nectria haematococca Berk. et Br. (880701a-1) causing nectria blight disease on ornamental plants.

A new antifungal diketopiperazine named haematocin was isolated from the culture broth of Nectria haematococca Berk. et Br. (880701a-1) causing blight disease on ornamental plants, Phalaenopsis spp. and Doritanopsis spp. Its structure was established by spectroscopic methods. Haematocin inhibited the germ-tube elongation and spore-germination of Pyricularia oryzae at the ED50 values of 30 microg/ml and 160 microg/ml, respectively.

Anti-Bacterial Agents↗
PubMed1999

Lucidenic acid O and lactone, new terpene inhibitors of eukaryotic DNA polymerases from a basidiomycete, Ganoderma lucidum.

Terpenoids, 1, 2 and 3, which selectively inhibit eukaryotic DNA polymerase activities, were isolated from the fruiting body of a basidiomycete, Ganoderma lucidum, and their structures were determined by spectroscopic analyses. New terpenes, lucidenic acid O (1) and lucidenic lactone (2), prevented not only the activities of calf DNA polymerase alpha and rat DNA polymerase beta, but also these of human immunodeficiency virus type 1 reverse transcriptase. Cerevisterol (3), which was reported to be a cytotoxic steroid, inhibited only the activity of DNA polymerase alpha. Although these compounds did not influence the activities of prokaryotic DNA polymerases and other DNA metabolic enzymes such as T7 RNA polymerase and deoxyribonuclease I.

Animals↗
PubMed1999

CH/pi interaction in the conformation of peptides. A database study.

A study was carried out, with use of the Cambridge Structural Database, to examine the role of the CH/pi interaction in the conformation of peptides. A number of short intramolecular CH/pi distances have been shown in the crystal structure of peptides bearing at least an aromatic residue in the sequence. The molecular structure in the crystal was inspected individually to know whether the conformation is merely a consequence of the so-called packing forces, or the CH/pi interaction plays a role. It has been demonstrated that the CH/pi interaction constitutes one of the key factors in controlling the conformation of peptides.

Amino Acid Sequence↗
PubMed1999

Triterpenoid saponins from Vaccaria segetalis.

A new triterpenoid saponin, named segetoside C (1), and two known saponins, vaccaroid A (vaccaroside A) (2) and dianoside G (3), have been isolated from the seeds of Vaccaria segetalis. On the basis of chemical reaction and spectral data, the structure of segetoside C (1) has been established as: gypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[6-O-acetyl-beta-D-glucopyra-nosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside.

Carbohydrate Sequence↗
PubMed1998

4-Hydroxy-17-methylincisterol, an inhibitor of DNA polymerase-alpha activity and the growth of human cancer cells in vitro.

An ergosterol derivative, 4-hydroxy-17-methylincisterol (HMI), was found to be an inhibitor of mammalian DNA polymerases in vitro. HMI inhibited the activity of calf thymus DNA polymerase alpha (pol. alpha). Among the polymerases tested, pol. alpha was the most sensitive to inhibition by HMI, and the inhibition was concentration dependent. The inhibitory effect of HMI on pol. alpha was almost the same as that shown by aphidicolin, a well-known potent pol. alpha inhibitor. HMI had relatively less effect on rat DNA pol. beta, human immunodeficiency virus type 1 reverse transcriptase (HIV-RT), and calf thymus terminal deoxynucleotidyl transferase (TdT) in vitro, and did not influence the activities of prokaryotic DNA polymerases such as Klenow Fragment of DNA polymerase I, or the DNA-metabolic enzyme DNase I. HMI was found to be able to prevent the growth of human cancer cell lines originating from patients with leukemia or various solid tumors; its IC50 values ranged from 7.5 to 12 microM. We also synthesized other ergosterol derivatives and tested them, and found that two compounds, 17-methylincisterol and 4-acetyl-17-methylincisterol, have similar inhibitory effects.

Animals↗
PubMed1998

An ergosterol peroxide, a natural product that selectively enhances the inhibitory effect of linoleic acid on DNA polymerase beta.

As described previously (Mizushina Y., Tanaka N., Yagi H., Kurosawa T., Onoue M., Seto H., Horie T., Aoyagi N., Yamaoka M., Matsukage A., Yoshida S., and Sakaguchi K., Biochim. Biophys. Acta, 1308, 256-262, 1996), linoleic acid (LA) inhibits the activities of mammalian DNA polymerases. We found a natural product from a basidiomycete, Ganoderma lucidum, that enhances this effect of LA in a special manner. The structure was identified to be an ergosterol peroxide, 5,8-epidioxy-5alpha,8alpha-ergosta-6,22E-dien -3beta-ol by spectroscopic analyses. The ergosterol peroxide (EPO) itself scarcely inhibited the activities of calf thymus DNA polymerase alpha (pol. alpha) or rat DNA polymerase beta (pol. beta). However, when EPO at 0.25 mM was present, 10 microM or less of LA almost completely inhibited the pol. beta activity, while almost complete inhibition by LA itself was achieved at 80 microM or higher. Interestingly, under the same conditions, EPO did not affect the LA-effect on pol. alpha. The action mode of the EPO was discussed.

Animals↗
PubMed1994

A new glucuronide saponin from tea leaves (Camellia sinensis var. sinensis.

A new glucuronide saponin (1) was isolated as its methyl ester (2) from the leaves of Camellia sinensis var. sinensis. On the basis of its spectral data and the results of chemical degradation, the structure was elucidated to be 3-O-[beta-D-galactopyranosyl(1-->2)-[beta-D- xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]- beta-D-glucuronopyranosyl]-21-O-cinnamoyl-16,22-di-O-acetylbarr ingtogenol C.

Carbohydrate Sequence↗
PubMed1993

Respinomycins A1, A2, B, C and D, a novel group of anthracycline antibiotics. II. Physico-chemical properties and structure elucidation.

Respinomycins A1, A2, B, C and D were revealed to be novel anthracycline antibiotics with molecular formulae of C51H72N2O20, C43H58N2O15, C35H43NO14, C36H45NO14 and C51H70N2O22, respectively. Their structures were determined by means of 1H-1H COSY, 13C-1H COSY and HMBC spectra. The structure of the aglycone of respinomycins was unambiguously determined by LSPD experiments and NOESY. The common skeleton of respinomycins is a new type and is distinguished from that of the nogalamycin group.

Anthracyclines↗
PubMed1991

Actiketal, a new member of the glutarimide antibiotics.

A new glutarimide antibiotic named actiketal was isolated from the culture fluid of the epiderstatin-producing streptomycete, Streptomyces pulveraceus subsp. epiderstagenes. The IC50 of the antibiotic for inhibition of the incorporation of [3H]thymidine into epidermal growth factor-stimulated Balb/MK cells was 14.5 microM. The structure of this compound was determined by 1H and 13C NMR spectroscopic analyses using 1H-1H COSY, 13C-1H COSY, heteronuclear multiple-bond correlation spectroscopy, selective 13C-[1H] NOE's techniques.

Animals↗
PubMed1990

New pyrrolobenzodiazepine antibiotics, RK-1441A and B. II. Isolation and structure.

Antibacteriophage antibiotics, RK-1441A and B, related to neothramycin were isolated from the culture broth of Streptomyces sp. and their structures were deduced from spectroscopic analyses. The structure of RK-1441A was 8,11-dihydroxy-3,7-dimethoxy-5-oxo-1H-pyrrolo[2,1-c:1,4]benzodiazepine. RK-1441B is a tautomeric mixture at C-3 of the structure, 3,8,11-trihydroxy-7-methoxy-5-oxo-1H-pyrrolo[2,1-c:1,4]benzodiazepine.

Anti-Bacterial Agents↗
PubMed1989

Epiderstatin, a new inhibitor of the mitogenic activity induced by epidermal growth factor. II. Structure elucidation.

The structure of a novel antibiotic, epiderstatin, was determined as 4-[3-((Z)-3,5-dimethyl-2-oxopiperidin-6-ylidene)-2-oxopropyl]-2, 6-piperidinedione by spectroscopic analyses of 1H NMR, 13C NMR, 1H-1H correlation spectroscopy (COSY), 13C-1H COSY, heteronuclear multiple bond correlation spectroscopy, UV and IR spectra. The antibiotic belongs to the glutarimide antibiotics, however, the characteristic feature of epiderstatin is that it has a piperidone ring instead of a cyclohexanone ring.

Antibiotics, Antineoplastic↗
PubMed1989

Biosynthesis and 13C NMR assignment of cytovaricin, a neutral macrolide antibiotic.

13C NMR analysis of 13C-labeled cytovaricin which was obtained by feeding sodium [1-13C]-, [2-13C]-, and [1,2-13C]acetates, [1-13C]- and [3-13C]propionates, [1-13C]isobutyrate and [methyl-13C]methionine to cultures of Streptomyces diastatochromogenes showed that the aglycone of cytovaricin is derived from nine acetate units, six propionate units and one isobutyrate unit and the methoxy group at C-3' of cymarose moiety is derived from the methionine-S-methyl group. The 13C NMR spectra of 13C-labeled cytovaricins which were obtained from feeding experiments allowed the complete assignment of the 13C NMR spectrum of cytovaricin.

Anti-Bacterial Agents↗