Publications by authors named "Hirotaka Katsuzaki"

YcjT is a kojibiose phosphorylase found in Escherichia coli. We found that sucrose was a good acceptor of YcjT in reverse phosphorolysis using β-d-glucose 1-phosphate as a donor. The product was identified as β-d-fructofuranosyl α-d-glucopyranosyl-(1→2)-α-d-glucopyranoside.

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Glycoside hydrolase family 94 (GH94) contains enzymes that reversibly catalyze the phosphorolysis of β-glycosides. We conducted this study to investigate a GH94 protein (PBOR_13355) encoded in the genome of Paenibacillus borealis DSM 13188 with low sequence identity to known phosphorylases. Screening of acceptor substrates for reverse phosphorolysis in the presence of α-d-glucose 1-phosphate as a donor substrate showed that PBOR_13355 utilized d-glucuronic acid and p-nitrophenyl β-d-glucuronide as acceptors.

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The immunomodulating effect of phlorotannin was investigated in mice stimulated by ovalbumin. When analyzing the main components of phlorotannin concentrate (PTC) from Eisenia nipponica, seven phlorotannins [eckol, 6,6'-bieckol, 6,8'-bieckol, 8,8'-bieckol, dieckol, phlorofucofuroeckol (PFF)-A, and PFF-B] were detected. These phlorotannins accounted for approximately 80% of PTC.

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The zebrafish obesogenic test (ZOT) is a powerful tool for identifying anti-adipogenic compounds for in vivo screening. In our previous study, we found that (MO) leaf powder suppressed the accumulation of visceral adipose tissue (VAT) in ZOT. MO demonstrates a wide range of pharmacological effects; however, little is known about its functional constituents.

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Various natural products (NPs) have been used to treat obesity and related diseases. However, the best way to fight obesity is preventive, with accurate body weight management through exercise, diet, or bioactive NPs to avoid obesity development. We demonstrated that green tea extract (GTE) is an anti-obesity NP using a zebrafish obesity model.

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Osteoporosis is the most common aging-associated bone disease and is caused by hyperactivation of osteoclastic activity. We previously reported that the hexane extract of ginger rhizome [ginger hexane extract (GHE)] could suppress receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells.

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We previously found a lipophilic fraction of the methanol/chloroform extract of a brown alga, Eisenia nipponica, that had an antiallergic effect in a murine ear swelling test. In this study, we purified the active component from the lipophilic fraction using high performance liquid chromatography and analyzed the mass and nuclear magnetic resonance spectra. This uncovered the phlorotannin dieckol, which exhibited antiallergic effects in an ear swelling test using mice sensitized by arachidonic acid, 12-O-tetradecanoylphorbol-13-acetate, and oxazolone.

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Ruminiclostridium josui Fae1A is a modular enzyme consisting of an N-terminal signal peptide, family-1 carbohydrate esterase module (CE1), family-6 carbohydrate-binding module (CBM6), and dockerin module in that order. Recombinant CE1 and CBM6 polypeptides were collectively and separately produced as RjFae1A, RjCE1, and RjCBM6. RjFae1A showed higher feruloyl esterase activity than RjCE1 towards insoluble wheat arabinoxylan, but the latter was more active towards small synthetic substrates than the former.

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Functional foods that inhibit α-amylase and α-glucosidase activity are effective for regulating the blood glucose level and preventing hyperglycemia. Extracts of adzuki beans (ABs, Vigna angularis), widely eaten in East Asia, can inhibit α-amylase and α-glucosidase activity. In this study, we identified and evaluated the components in an AB water extract (ABWE) after boiling, which is an essential process for cooking ABs.

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Osteoporosis is a systemic skeletal disease that causes bone weakness and fragility. Consuming bone-beneficial nutrients through diet can prevent and treat osteoporosis. (Japanese maple) leaves are used to make tea, but there have been few reports of their health benefits, especially regarding bone homeostasis.

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Phlorotannin is the collective term for polyphenols derived from brown algae belonging to the genera , , , and etc. Since the incidence of allergies is currently increasing in the world, there is a focus on phlorotannins having anti-allergic and anti-inflammatory effects. In this study, six purified phlorotannins (eckol; 6,6'-bieckol; 6,8'-bieckol; 8,8'-bieckol; phlorofucofuroeckol (PFF)-A and PFF-B) from , orally administered to mice, were examined for their suppression effects on ear swelling.

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Ruminiclostridium josui Abf62A-Axe6A is a modular enzyme comprising (in order from the N-terminus): an N-terminal signal peptide, a glycoside hydrolase family 62 (GH62) catalytic module, a family 6 carbohydrate binding module (CBM6), a dockerin module and an additional carbohydrate esterase family 6 catalytic module (CE6). In this study, three Abf62A-Axe6A derivatives were constructed, overexpressed in Escherichia coli, purified, and biochemically characterized: RjAbf62A-Axe6A, containing all four modules but lacking the signal peptide; RjAbf62A-CBM6, containing the GH62 and CBM6 modules; and RjAxe6A, containing only CE6. RjAbf62A-Axe6A was highly active toward arabinoxylan and moderately active toward sugar beet arabinan, and released mainly arabinose.

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Paenibacillus curdlanolyticus B-6 Xyn10C is a single module xylanase consisting of a glycoside hydrolase family-10 catalytic module. The recombinant enzyme, rXyn10C, was produced by Escherichia coli and characterized. rXyn10C was highly active toward soluble xylans derived from rye, birchwood, and oat spelt, and slightly active toward insoluble wheat arabinoxylan.

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The genome sequence of Bacillus licheniformis SVD1, that produces a cellulolytic and hemi-cellulolytic multienzyme complex, was partially determined, indicating that the glycoside hydrolase system of this strain is highly similar to that of B. licheniformis ATCC14580. All of the fifty-six genes encoding glycoside hydrolases identified in B.

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Eisenia arborea is an edible brown alga occasionally used as a folk medicine in gynecopathy in Japan. A new phlorotannin was isolated from the alga during our search for naturally occurring anti-allergic compounds from edible algae guided by the inhibitory effect on histamine release from rat basophile leukemia (RBL)-2H3 cells. The phlorotannin was called "phlorofucofuroeckol-B.

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Five types of flavonol were isolated from seabuckthorn (Hippophae rhamnoides) and identified by mass, 1H- and 13C-NMR. The proliferations of human promyelotic leukemia HL-60 cells were inhibited as the concentrations of these flavonols were increased. The order of the extent of growth inhibition by the flavonols at a concentration of 20 microM is as follows: pentamethylquercetin > syringetin > isorhamnetin > quercetin > kaempherol > myricetin.

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The comparison of antioxidative activity between the hot water extract and ambient water extract of Japanese radish (daikon) was carried out. The activity of the hot water extract was higher than that of the ambient water extract. One of the antioxidants was isolated as L-tryptophan that should no change in its amount that was determined between the hot water extract and ambient water extract.

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We have investigated the effects of maackiain and trifolirhizin (maackiain glycoside) isolated from sanzukon (Sophora Subprostrate Chen et T. Chen) on DNA of human promyelotic HL-60 leukemia cells. It was found that extent of induction of apoptosis by maackiain was larger than that by trifolirhizin in human leukemia HL-60 cells.

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2-O-methylisohemigossylic acid lactone, a sesquiterpene, was purified from roots of mokumen (Gossampinus malabarica) and identified by Mass, and (1)H- and (13)-NMR. This sesquiterpene displayed strong growth inhibitory effect against human promyelotic leukemia HL-60 cells. Apoptotic morphological change of the nucleus, including chromatin condensation was induced in the HL-60 cells treated with the sesquiterpene.

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We have investigated the effect of lupeol (lup-20(29)-ene-3beta-ene-3-ol) isolated from mokumen (Gossampinus malabarica L. Merr) on DNA of human promyelotic HL-60 leukemia cells. Induction of apoptosis by lupeol was observed in human leukemia HL-60 cells.

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Hot water soluble (HWS)-sesquiterpenes [anhydroperoxycostunolide and 3-oxo-eudesma-1,4(15),11(13)triene-12,6alpha-olide] were purified from Laurel (Laurus nobilis L.) and identified by Mass, and 1H- and 13C-NMR. These HWS-sesquiterpenes displayed strong growth inhibitory effect against human promyelotic leukemia HL-60 cells.

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Sesquiterpenes (costunolide and zaluzanin D) were purified from laurel (Laurus nobilis L.) and identified by Mass, and 1H- and 13C-NMR. These sesquiterpenes displayed strong growth inhibitory effect against human promyelotic leukemia HL-60 cells.

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Cyanidin 3-O-beta-D-glucoside (CG) was purified from black bean seed coat and other anthocyanins were prepared from red grape skin. These anthocyanins were identified by Mass, and 1H- and 13C-NMR. The effects of four anthocyanins on cell viability in human leukemia Molt 4B cells were investigated.

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Protodioscin (PD) was purified from fenugreek (Trigonella foenumgraecum L.) and identified by Mass, and 1H- and 13C-NMR. The effects of PD on cell viability in human leukemia HL-60 and human stomach cancer KATO III cells were investigated.

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