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Biomedical subjects

Y Fukagawa

Publications and source records attributed to Y Fukagawa.

At least 19 recordsLinked to original sources
PubMed1995

Screening and production of arylsulfatases for target therapy with etoposide 4'-sulfate, an antitumor prodrug.

Two arylsulfatase-producing streptomycetes that desulfated etoposide 4'-sulfate were isolated from soil samples. Taxonomical study identified one soil isolate as Streptomyces griseorubiginosus S980-14 (Es-1 arylsulfatase producer), while the other was considered new and tentatively designated Streptomyces sp. T109-3 (Es-2 arylsulfatase producer). Both strains produced extracellular arylsulfatase activities, provided that cultivation media were prepared with distilled water. Unlike the two known types of arylsulfatases, which had significant activity on p-nitrophenyl sulfate but none on etoposide 4'-sulfate, the crude streptomycete arylsulfatases efficiently desulfated etoposide 4'-sulfate and p-nitrophenyl sulfate, which supports the establishment of a new type of arylsulfatases.

Antineoplastic Agents↗
PubMed1995

Arylsulfatase from Streptomyces griseorubiginosus S980-14.

A new arylsulfatase designated Es-1, which desulfated etoposide 4'-sulfate and p-nitrophenyl sulfate, was isolated from Streptomyces griseorubiginosus S980-14 and purified to protein homogeneity by ammonium sulfate fractionation, ion exchange column chromatography, and chromatofocusing. The enzyme was active in monomeric form with an approximate molecular weight of 45,000, had a pI value of 4.95, and required calcium for full activity. At an optimum reaction pH of 8.5, iodoacetate, mercurous chloride, and EDTA severely inhibited the activity of Es-1 arylsulfatase.

Arylsulfatases↗
PubMed1995

A new type of Streptomycete arylsulfatase with high affinity to the sulfuryl moiety of the substrate.

Streptomyces sp. T109-3 arylsulfatase (Es-2), which desulfated p-nitrophenyl sulfate as well as etoposide 4'-sulfate, was purified to protein homogeneity by sulfated cellulose affinity and DEAE-cellulose column chromatographies. Es-2 required calcium for enzyme activity and was severely inhibited by SH and chelating reagents. Comparative characterization showed that, although distinct in recognition of the binding moiety of substrate, Es-1 (Streptomyces griseorubiginosus S980-14 arylsulfatase) and Es-2 shared high desulfating activity on etoposide 4'-sulfate and many other common enzymological characteristics, which suggested they would be acceptable as the enzyme component of antitumor antibody-enzyme conjugates for target chemotherapy.

Amino Acid Sequence↗
PubMed1994

Eurystatins A and B, new prolyl endopeptidase inhibitors. III. Fermentation and controlled biosynthesis of eurystatin analogs by Streptomyces eurythermus.

Accurate and precise component analysis of eurystatin analogs in fermentation broth was devised by HPLC methods with and without 2,4-dinitrophenylhydrazonation. Detailed optimization of fermentation conditions and strain improvement by HPLC analysis significantly increased the eurystatin productivity of Streptomyces eurythermus. Chemically defined fermentation media which produced eurystatins A and B at fermentation yields comparable to complex media were elaborated for radio-isotope fermentation studies and controlled biosynthesis. Radio-isotope incorporation study using 14C-labeled amino acids in chemically defined medium demonstrated that L-leucine and L-ornithine were the direct precursors for the L-leucine and L-ornithine moieties of eurystatins A and B, respectively. Based on this finding, L-valine and L-isoleucine were supplemented to the growing culture of S. eurythermus in chemically defined medium, which resulted in the controlled biosynthesis of new eurystatin analogs named eurystatins C, D, E and F.

Amino Acids↗
PubMed1993

Studies on the mode of antifungal action of pradimicin antibiotics. I. Lectin-mimic binding of BMY-28864 to yeast mannan in the presence of calcium.

BMY-28864 (BMS-181184), a water-soluble pradimicin derivative, specifically bound on the yeast cell surface in the presence of calcium, which was considered to be the initial step that triggered chain reactions leading to the fungicidal action. Close cause-effect relationships of the cell wall binding of BMY-28864 with its antifungal activity and potassium leakage induction were observed by Candida albicans and Saccharomyces cerevisiae in the presence and absence of calcium. Using mannan and methyl alpha-D-mannopyranoside as specific sugars, the mode of binding of BMY-28864 to sugar was examined in vitro in the presence of calcium. Quantitative component analysis revealed that the precipitate of BMY-28864 with methyl alpha-D-mannopyranoside and calcium was a ternary complex possessing a molar component ratio of 2.1:4.3:1.0. These findings altogether proved that BMY-28864, although not protein, recognized specific sugars such as mannose in the same manner as lectin, and that the ternary complex formation of BMY-28864 with specific sugar and calcium was the first step for expression of the selective antifungal action of the pradimicin.

Adsorption↗
PubMed1993

Epocarbazolins A and B, novel 5-lipoxygenase inhibitors. Taxonomy, fermentation, isolation, structures and biological activities.

New 5-lipoxygenase inhibitors, designated epocarbazolins A and B, were isolated from the culture broth of Streptomyces anulatus T688-8. These compounds showed potent rat 5-lipoxygenase inhibitory activity with weak antibacterial activity. Structural studies revealed that epocarbazolins are new carbazole antibiotics having a novel substitution pattern and an epoxide in the side chain.

Animals↗
PubMed1993

Terpestacin, a new syncytium formation inhibitor from Arthrinium sp.

Terpestacin, a new antibiotic which inhibits syncytium formation, was isolated from Arthrinium sp. FA1744 (ATCC 74132). The structure of terpestacin was elucidated as a bicyclic sesterterpene on the basis of spectroscopic data and chemical derivatization.

Anti-Bacterial Agents↗
PubMed1993

Studies on the mode of antifungal action of pradimicin antibiotics. II. D-mannopyranoside-binding site and calcium-binding site.

Based on the structure-activity relationship data of BMY-28864 and related pradimicin derivatives, the calcium salt-forming ability and the D-mannopyranoside-specific visible absorption maximum shift of BMY-28864 were analysed in the ternary complex formation of BMY-28864 with D-mannopyranoside and calcium. The free C-18 carboxyl group of BMY-28864 was proved to be the sole site for binding to calcium, while no hydroxyl groups of the aglycone were involved in calcium salt formation. The stereospecific D-mannopyranoside-recognizing ability of BMY-28864 was completely abolished by removal of the C-5 disaccharide moiety, and, more particularly, of the C-5 thomosamine moiety. Close relationship of these findings with the antifungal action was also supported by the in vitro antifungal assay and the potassium leakage induction test.

Anthracyclines↗
PubMed1993

Studies on the mode of antifungal action of pradimicin antibiotics. III. Spectrophotometric sequence analysis of the ternary complex formation of BMY-28864 with D-mannopyranoside and calcium.

Sequence of reactions in the process of ternary complex formation of BMY-28864 with D-mannopyranoside and calcium was spectrophotometrically determined under more strict analytical conditions using metal-free preparations of sugars and the pradimicin derivative at a bandpass slit width of 1 nm. In the first phase of ternary complex formation, BMY-28864 stereospecifically recognized and bound to D-mannopyranoside in the absence of calcium, which was revealed by a visible absorption maximum shift of ca. 8 nm. Subsequently, the BMY-28864-D-mannopyranoside conjugate reacted with calcium to yield the ternary complex, which was detected by an additional visible absorption maximum shift of ca. 8 nm. When the three components were mixed at the same time, both phases simultaneously occurred to produce the ternary complex which was accompanied by a visible absorption maximum shift of 16 nm in total. Based on this two-phased reaction sequence, the mechanism of ternary complex formation of BMY-28864 with D-mannopyranoside and calcium was reexamined in details. Terminal D-mannopyranoside was confirmed to be essential as BMY-28864-specific sugar receptor by in vitro analysis and animal cell experiments. While calcium, strontium and cadmium behaved similar in the in vitro ternary complex formation, the yeast and animal cell experiments showed that only calcium played a dual role as a base in the ternary complex formation and as an effector in physiological disturbances leading to cell death.

Animals↗
PubMed1992

Protective effect of eurystatins A and B, new prolyl endopeptidase inhibitors, on scopolamine-induced amnesia in rats.

Eurystatins A and B, which are produced by Streptomyces eurythermus R353-21, potently inhibited Flavobacterium prolyl endopeptidase (PED) with IC50 values of 0.004 and 0.002 micrograms/ml, respectively, while no inhibition was observed against another 5 proteases, even at 100 micrograms/ml. The protective effect of eurystatins A and B against scopolamine (3 mg/kg, i.p.)-induced amnesia in rats was evaluated by the step-through one-trial passive avoidance method. When administered i.p. 30 min prior to the acquisition trial, both eurystatins A, at 2-8 mg/kg, and B, at 4-8 mg/kg, significantly protected rats from the amnesic effect of scopolamine without behavioral side effects.

Amino Acid Sequence↗
PubMed1992

[Effects of dietary proteins on analgesic activity of tolerance and physical dependence on morphine in rats].

Effects of dietary proteins such as casein and egg albumin on analgesic activity of, tolerance to and physical dependence on morphine in rats were examined. There was no difference in analgesic activity after acute administration of morphine 10 mg/kg, s.c. between rats treated with casein food or egg albumin food and normal food for 5 or 21 days. The development of tolerance to morphine analgesia in rats treated with albumin food but not with casein food was suppressed during daily morphine 10 mg/kg, s.c. on 5 consecutive days. Rats were treated with casein or albumin food mixed with morphine (0.5 mg/g of food) for 5 days. Morphine intake in rats treated with albumin food was significantly decreased as compared to that with morphine admixed casein or normal food. Body weight loss by naloxone in morphine-dependent rats was significantly less in both casein food and albumin food groups than in the normal food group. These results suggest that chronic dietary treatment with albumin may produce a partial inhibition of development of tolerance to morphine analgesia and that with casein may attenuate morphine withdrawal manifestation in rats.

Analgesics, Opioid↗
PubMed1991

Syntheses and biological properties of new 8-fluorocarbapenem derivatives.

8-Fluorocarbapenem derivatives having various C-3 side chains were synthesized to study for the structure-activity relationship of carbapenems by in vitro biological evaluation. The introduction of fluorine at C-8 of racemic PS-5 led to slight improvements of the antimicrobial activity and the stability to renal dehydropeptidase-I. When D-cysteine was additionally introduced to the C-3 position of (+/-)-8-fluorocarbapenem, the diastereomeric separation of the 8-fluorocarbapenems became feasible. As expected from penicillins and cephalosporins, (+)-8-fluoro-3-D-cysteinylcarbapenem (+)-7a was antimicrobially active, whereas (-)-7b was inactive. It is worth noting, however, that (+)-7a was significantly more sensitive to renal dehydropeptidase-I than (-)-7b. Irrespective of the presence of fluorine at C-8, basic S-side chains at C-3, such as the pyridyl and pyrrolidyl groups, significantly improved in antimicrobial activity and dehydropeptidase-I stability. The combination of 8-fluorination with C-3 basic side chains in 7c--g resulted in a marked improvement of antimicrobial activity and dehydropeptidase-I stability.

Anti-Bacterial Agents↗
PubMed1991

Kinetic analysis of dehydropeptidase-I and comparative in vitro and in vivo stabilities of PS-5 derivatives modified at the C-3 side chain.

With partially purified kidney dehydropeptidase-I (DHP-I) preparations, the hydrolysis kinetics of glycyldehydrophenylalanine (Gly-dPh) by DHP-I were found to be completely non-Michaelian, whereas those of PS-5 and imipenem were composed of at least two-phase reactions which were also observed using Bacillus cereus type II beta-lactamase. Thus the DHP-I stabilities of 34 PS-5 carbapenem derivatives which were synthesized by chemical modification at the C-3 side chain of PS-5 were examined in vitro using fresh mouse, dog and human DHP-I preparations, and are tentatively expressed in reference to the DHP-I stabilities of PS-5. The in vitro DHP-I stability of PS-5 was significantly improved by introduction of basic side chains and cysteines at C-3. More particularly, the D-cysteinyl side chain was more stable relative to DHP-I than the L-cysteinyl. In vivo, however, the degree of improvement of the DHP-I-stability by chemical modification at C-3 was not sufficient enough to establish therapeutically effective levels of serum concentrations and urinary recoveries of the carbapenem derivatives after parenteral administration.

Animals↗