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133 results on '"Kazuma, Kohei"'

10. Chemical and biological characterization of four new linear cationic α-helical peptides from the venoms of two solitary eumenine wasps

Author

Rangel, Marisa, dos Santos Cabrera, Marcia Perez, Kazuma, Kohei, Ando, Kenji, Wang, Xiaoyu, Kato, Manabu, Nihei, Ken-ichi, Hirata, Izaura Yoshico, Cross, Tyra J., Garcia, Angélica Nunes, Faquim-Mauro, Eliana L., Franzolin, Marcia Regina, Fuchino, Hiroyuki, Mori-Yasumoto, Kanami, Sekita, Setsuko, Kadowaki, Makoto, Satake, Motoyoshi, and Konno, Katsuhiro

Published
2011
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16. Characterization of metabolites in Saposhnikovia divaricata root from Mongolia

Author

Batsukh, Zolboo, primary, Toume, Kazufumi, additional, Javzan, Batkhuu, additional, Kazuma, Kohei, additional, Cai, Shao-Qing, additional, Hayashi, Shigeki, additional, Atsumi, Toshiyuki, additional, Yoshitomi, Taichi, additional, Uchiyama, Nahoko, additional, Maruyama, Takuro, additional, Kawahara, Nobuo, additional, and Komatsu, Katsuko, additional

Published
2020
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20. Comprehensive analysis of peptides and low molecular weight components of the giant ant Dinoponera quadriceps venom. Biological Chemistry

Author

Rádis-Baptista, Gandhi, Dodou, Hilania V., Prieto-da-Silva, Álvaro R. B., Zaharenko3, André J., Kazuma, Kohei, Nihei, Ken-Ichi, Inagaki, Hidetoshi, Mori-Yasumoto, Kanami, and Konno, Katsuhiro

Subjects
Venenos, Formiga
Abstract

Ants (Hymenoptera, Apocrita, Aculeata, Formicoidea) comprise a well-succeeded group of animals. Like bees and wasps, ants are mostly venomous, having a sting system to deliver a mixture of bioactive organic compounds and peptides. The predatory giant ant Dinoponera quadriceps belongs to the subfamily Ponerinae that include one of the largest known ant species in the world. In the present study, low molecular weight compounds and peptides were identified by on-line peptide mass fingerprint. These include neuroactive biogenic amines (histamine, tyramine, and dopamine), monoamine alkaloid (phenethylamine), free amino acids (e.g., glutamic acid and proline), free thymidine and cytosine. To the best of our knowledge most of these components are described for the first time in an ant venom. Multifunctional dinoponeratoxin peptides variants (pilosulin- and ponericin-like peptides) were characterized that possess antimicrobial, hemolytic, and histamine-releasing properties. These venom components, particularly peptides, might synergistically contribute to the overall venom activity and toxicity, for immobilizing live prey, and defending D. quadricepsagainst aggressors, predators and potential microbial infection.

Published
2019

31. Localization Analysis of Natural Toxin of Solanum tuberosum L. via Mass Spectrometric Imaging

Author

Hashizaki, Riho, Komori, Hanaka, Kazuma, Kohei, Konno, Katsuhiro, Kawabata, Kyuichi, Kaneko, Daisaku, Katano, Hajime, Taira, Shu, Hashizaki, Riho, Komori, Hanaka, Kazuma, Kohei, Konno, Katsuhiro, Kawabata, Kyuichi, Kaneko, Daisaku, Katano, Hajime, and Taira, Shu

Abstract

The use of mass spectrometry imaging (MSI) revealed the localization of a-solanine and a-chaconine as natural toxins for Potato (Solanum tuberosum L.). The content of Potato glycoalkaloids, a-solanine and a-chaconine, were quantitatively determined by high performance liquid chromatography (HPLC). Matrix assisted laser desorption/ionization-based tandem mass spectrometry (MS) could determine a-solanine and a-chaconine from raw potato extraction and section. After budbreak, a-solanine and a-chaconine were produced and localized at periderm and germ compared with that before budbreak. At germ region, these glycoalkaloids did not exist whole germ region but eccentrically localize at germ surface and central region. The amount of a-chaconine was twofold higher than a-solanine at periderm. At germ region, there was no difference between these toxins.

Published
2016

38. Peripheral 5-HT3 Receptors Are Involved in the Antinociceptive Effect of Bunodosine 391.

Author

Ferreira Junior, Wilson Alves, Zaharenko, Andre Junqueira, Kazuma, Kohei, Picolo, Gisele, Gutierrez, Vanessa Pacciari, de Freitas, Jose Carlos, Konno, Katsuhiro, and Cury, Yara

Subjects
MARINE toxins, ANALGESICS, CELL receptors, MOLECULAR weights, SEA anemones, NOCICEPTIVE pain, HYPERALGESIA
Abstract

Bunodosine 391 (BDS 391), a low molecular weight compound isolated from the sea anemone Bunodosoma cangicum, increases the nociceptive threshold and inhibits inflammatory hyperalgesia. Serotonin receptors are involved in those effects. In this study, we have expanded the characterization of the antinociceptive effect of BDS 391 demonstrating that, in rats: (a) the compound inhibits (1.2-12 ng/paw) overt pain, in the formalin test, and mechanical hyperalgesia (0.6-6.0 ng/paw) detected in a model of neuropathic pain; (b) intraplantar administration of ondansetron, a selective 5-HT3 receptor antagonist, blocks the effect of BDS 391, whereas ketanserin, a 5-HT2 receptor antagonist, partially reversed this effect, indicating the involvement of peripheral 5-HT2 and 5-HT3 receptors in BDS 391 antinociception; and (c) in binding assay studies, BDS 391 was not able to displace the selective 5-HT receptor antagonists, suggesting that this compound does not directly bind to these receptors. The effect of biguanide, a selective 5-HT3 receptor agonist, was also evaluated. The agonist inhibited the formalin's nociceptive response, supporting an antinociceptive role for 5-HT3 receptors. Our study is the first one to show that a non-peptidic low molecular weight compound obtained from a sea anemone is able to induce antinociception and that activation of peripheral 5-HT3 receptors contributes to this effect. [ABSTRACT FROM AUTHOR]

Published
2018
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46. Active Constituents from Drynaria fortuneiRhizomes on the Attenuation of Aβ25–35-Induced Axonal Atrophy

Author

Yang, Zhi-You, Kuboyama, Tomoharu, Kazuma, Kohei, Konno, Katsuhiro, and Tohda, Chihiro

Abstract

Axonal regeneration might contribute to the restoration of damaged neuronal networks and improvement of memory deficits in a murine Alzheimer’s disease (AD) model. A search for axonal regenerative drugs was performed to discover novel therapeutic options for AD. In this study, an aqueous extract of Drynaria fortuneirhizomes reversed Aβ25–35-induced axonal atrophy in cultured cortical neurons of mice. Bioassay-guided fractionation of this extract led to the isolation and identification of compounds 1–5. Among them, (2S)-neoeriocitrin (2) and caffeic acid 4-O-glucoside (4) showed significant axonal elongation effects on Aβ25–35-induced atrophy.

Published
2015
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48. Crystal structure of UDP-glucose:anthocyanidin 3- O-glucosyltransferase from Clitoria ternatea.

Author

Hiromoto, Takeshi, Honjo, Eijiro, Tamada, Taro, Noda, Naonobu, Kazuma, Kohei, Suzuki, Masahiko, and Kuroki, Ryota

Subjects
URIDINE diphosphate, ANTHOCYANIDINS, GLYCOSYLTRANSFERASES, GLYCOGEN synthases, GENETIC regulation, ESCHERICHIA coli
Abstract

Flowers of the butterfly pea ( Clitoria ternatea) accumulate a group of polyacylated anthocyanins, named ternatins, in their petals. The first step in ternatin biosynthesis is the transfer of glucose from UDP-glucose to anthocyanidins such as delphinidin, a reaction catalyzed in C. ternatea by UDP-glucose:anthocyanidin 3- O-glucosyltransferase ( Ct3GT-A; AB185904). To elucidate the structure-function relationship of Ct3GT-A, recombinant Ct3GT-A was expressed in Escherichia coli and its tertiary structure was determined to 1.85 Å resolution by using X-ray crystallography. The structure of Ct3GT-A shows a common folding topology, the GT-B fold, comprised of two Rossmann-like β/α/β domains and a cleft located between the N- and C-domains containing two cavities that are used as binding sites for the donor (UDP-Glc) and acceptor substrates. By comparing the structure of Ct3GT-A with that of the flavonoid glycosyltransferase VvGT1 from red grape ( Vitis vinifera) in complex with UDP-2-deoxy-2-fluoro glucose and kaempferol, locations of the catalytic His-Asp dyad and the residues involved in recognizing UDP-2-deoxy-2-fluoro glucose were essentially identical in Ct3GT-A, but certain residues of VvGT1 involved in binding kaempferol were found to be substituted in Ct3GT-A. These findings are important for understanding the differentiation of acceptor-substrate recognition in these two enzymes. [ABSTRACT FROM AUTHOR]

Published
2013
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49. Quinochalcones and Flavonoids from Fresh Florets in Different Cultivars of Carthamus tinctoriusL.

Author

KAZUMA, Kohei, TAKAHASHI, Takashi, SATO, Katsura, TAKEUCHI, Hisatomo, MATSUMOTO, Takeshi, and OKUNO, Toshikatsu

Abstract

The flavonoid constituents in fresh florets of the three distinctive cultivars of Carthamus tinctoriusL. were purified and identified to investigate flavonoid biosynthesis in the petals. From the orange flower of cv. Ken-ba (K.), four new compounds, anhydrosafflor yellow B (1), two kaempferols, 9 and 13, and a quercetin, 17, were isolated, as well as the twelve known compounds, and their structures were determined by spectral data, chemical reactions, and molecular mechanics calculations. From the yellow flower of cv. Ogon-hanagasa (O.), two flavonols and two quinochalcones, and from the white flower of cv. Shiro-bana (S.), three flavonols were isolated. These compounds were the same as those contained in cv. K. To compare the flavonoid constituents among the three cultivars, crude extracts were analyzed by a LC/PDA/MS system. In cv. K., six quinochalcones and eleven flavonols were identified. In cv. O., three quinochalcones and nine flavonols were identified, but the red pigment, carthamin (4), and its precursor, precarthamin (3), were not detected. In cv. S., four flavonols without a 6-hydroxyl group were identified. On the basis of a comparative study on the constituents among these three cultivars, a possible biosynthetic pathway to form quinochalcones viathe intermediate, pentahydroxychalcone (19), is proposed.

Published
2000
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50. Crataegusins A and B, New Flavanocoumarins from the Dried Fruits of Crataegus pinnatifidavar. major(Rosaceae)

Author

Kazuma, Kohei, Isobe, Yuka, Asahina, Haruka, Nehira, Tatsuo, Satake, Motoyoshi, and Konno, Katsuhiro

Abstract

Crataegusins A (1) and B (2), new flavanocoumarins, were isolated from the crude drug Crataegus Fructus, i.e., the dried fruits of Crataegus pinnatifida var. major. Their structures were determined by spectroscopic methods. They were unique in terms of carrying a 3-(or 4-)substituted coumarin substructure while a flavanocoumarin generally does not carry any substituents in the 2-pyron ring. They showed a significant DPPH reducing activity compared with epicatechin. Their production would be biosynthetically regulated considering the results of an LC-MS analysis of the dried and fresh fruits, fruit skin, hypanthia, and leaves. Their structures led the authors to consider a hypothetical general biosynthetic pathway of the flavanocoumarins, to which a flavan-3-ol is converted through a Michael addition and successive oxidative decarboxylation or dehydration pathway.

Published
2016
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