Faculty Profiles - MURATA Yoshiyuki

Papers - MURATA Yoshiyuki

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Purification and characterization of a cathepsin L-like enzyme from the body wall of the sea cucumber Stichopus japonicus. International journal

Bei-Wei Zhu, Lu-Lu Zhao, Li-Ming Sun, Dong-Mei Li, Yoshiyuki Murata, Lei Yu, Lei Zhang

Bioscience, biotechnology, and biochemistry 72 ( 6 ) 1430 - 7 2008.6

Language：English Publishing type：Research paper (scientific journal)

Cathepsin L-like enzyme was purified from the body wall of the sea cucumber Stichopus japonicus by an integral method involving ammonium sulfate precipitation and a series of column chromatographies on DEAE Sepharose CL-6B, Sephadex G-75, and TSK-GEL. The molecular mass of the purified enzyme was estimated to be 63 kDa by SDS-PAGE. The enzyme cleaved N-carbobenzoxy-phenylalanine-arginine7-amido-4-methylcoumarin with K(m) (69.92 microM) and k(cat) (12.80/S) hardly hydrolyzed N-carbobenzoxy-arginine-arginine 7-amido-4-methylcoumarin and L-arginine 7-amido-4-methylcoumarin. The optimum pH and temperature for the purified enzyme were found to be 5.0 and 50 degrees C. It showed thermal stability below 40 degrees C. The activity was inhibited by sulfhydryl reagents and activated by reducing agents. These results suggest that the purified enzyme was a cathepsin L-like enzyme and that it existed in the form of its enzyme-inhibitor complex or precursor.

Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells. International journal

Md Anamul Hoque, Mst Nasrin Akhter Banu, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

Journal of plant physiology 165 ( 8 ) 813 - 24 2008.5

Language：English Publishing type：Research paper (scientific journal)

Salt stress impairs reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems, and causes oxidative damage to plants. Up-regulation of the antioxidant and glyoxalase systems provides protection against NaCl-induced oxidative damage in plants. Thiol-disulfide contents, glutathione content and its associated enzyme activities involved in the antioxidant defense and glyoxalase systems, and protein carbonylation in tobacco Bright Yellow-2 cells grown in suspension culture were investigated to assess the protection offered by proline and glycinebetaine against salt stress. Salt stress increased protein carbonylation, contents of thiol, disulfide, reduced (GSH) and oxidized (GSSG) forms of glutathione, and the activity of glutathione-S-transferase and glyoxalase II enzymes, but decreased redox state of both thiol-disulfide and glutathione, and the activity of glutathione peroxidase and glyoxalase I enzymes involved in the ROS and MG detoxification systems. Exogenous application of proline or glycinebetaine resulted in a reduction of protein carbonylation, and in an increase in glutathione redox state and activity of glutathione peroxidase, glutathione-S-transferase and glyoxalase I under salt stress. Neither proline nor glycinebetaine, however, had any direct protective effect on NaCl-induced GSH-associated enzyme activities. The present study, therefore, suggests that both proline and glycinebetaine provide a protective action against NaCl-induced oxidative damage by reducing protein carbonylation, and enhancing antioxidant defense and MG detoxification systems.

Properties of an alginate-degrading Flavobacterium sp. strain LXA isolated from rotting algae from coastal China. International journal

Qing-Da An, Gong-Liang Zhang, Hai-Tao Wu, Zhen-Cheng Zhang, Guo-Shuang Zheng, Ying-Li Zhang, Xian-Zhen Li, Yoshiyuki Murata

Canadian journal of microbiology 54 ( 4 ) 314 - 20 2008.4

Language：English Publishing type：Research paper (scientific journal)

A novel bacterium exhibiting alginolytic activity was isolated from rotten algae. The alginate-degrading activity was detected in the culture supernatant by measuring the decrease in alginate viscosity or the increase in reducing sugars. Basic characterization showed that it was gram negative, rod shaped, yellow pigmented, and positive for oxidase and catalase, with a DNA G+C content of 35.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that this strain is related to members of the genus Flavobacterium. Sequence similarity values with their nearest phylogenetic neighbours ranged from 95.9% to 96.7%. Genotypic results, together with phenotypic characteristics, differentiated this species from related Flavobacterium organisms with validly published names, which suggests that the organism should be a new species of the genus Flavobacterium tentatively named as Flavobacterium sp. strain LXA.

DOI： 10.1139/w08-013

Salt-adaptation of tobacco BY2 cells induces change in glycoform of N-glycans: Enhancement of exo- and endo-glycosidase activities by salt-adaptation Reviewed International journal

Yoshinobu Kimura, Takao Watanabe, Mariko Kimura, Megumi Maeda, Yoshiyuki Murata, Kazuhito Fujjyama

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 72 ( 2 ) 514 - 522 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

In this report, we describe that a salt adaptation of plant cells induces glycoform changes in N-glycoproteins. Intracellular and cell-wall glycopeptides were prepared from glycoproteins expressed in wild-type BY2 cells and salt-adapted cells. N-Glycans were liberated from those glycopeptides by hydrazinolysis, and the released oligosaccharides were N-acetylated and pyridylaminated. The structures of pyridylaminated (PA-) N-glycans were analyzed by a combination of two-dimensional sugar-chain mapping, MS analysis, and exoglycosidase digestion. In both wild-type cells and salt-adapted cells, the plant complex type structure was predominant among N-glycans expressed on glycoproteins, but we found that the Man2Xyl1Fuc1GlcNAc2 structure was significantly expressed on intracellular and cell-wall glycoproteins of the salt-adapted cells. Furthermore, enhancement of the specific activities of alpha-mannosidase and beta-N-acetylglucosaminidase was observed in the salt-adapted BY2 cells, suggesting that the glycoform changes are due to changes in glycosidase activities.

DOI： 10.1271/bbb.70592

Characterization of a tobacco TPK-type K+ channel as a novel tonoplast K+ channel using yeast tonoplasts Reviewed International journal

Shin Hamamoto, Junichiro Marui, Ken Matsuoka, Kyohei Higashi, Kazuei Igarashi, Tsuyoshi Nakagawa, Teruo Kuroda, Yasuo Mori, Yoshiyuki Murata, Yoichi Nakanishi, Masayoshi Maeshima, Isamu Yabe, Nobuyuki Uozumi

JOURNAL OF BIOLOGICAL CHEMISTRY 283 ( 4 ) 1911 - 1920 2008.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

The tonoplast K+ membrane transport system plays a crucial role in maintaining K+ homeostasis in plant cells. Here, we isolated cDNAs encoding a two-pore K+ channel (NtTPK1) from Nicotiana tabacum cv. SR1 and cultured BY-2 tobacco cells. Two of the four variants of NtTPK1 contained VHG and GHG instead of the GYG signature sequence in the second pore region. All four products were functional when expressed in the Escherichia coli cell membrane, and NtTPK1 was targeted to the tonoplast in tobacco cells. Two of the three promoter sequences isolated from N. tabacum cv. SR1 were active, and expression from these was increased similar to 2-fold by salt stress or high osmotic shock. To determine the properties of NtTPK1, we enlarged mutant yeast cells with inactivated endogenous tonoplast channels and prepared tonoplasts suitable for patch clamp recording allowing the NtTPK1-related channel conductance to be distinguished from the small endogenous currents. NtTPK1 exhibited strong selectivity for K+ over Na+. NtTPK1 activity was sensitive to spermidine and spermine, which were shown to be present in tobacco cells. NtTPK1 was active in the absence of Ca2+, but a cytosolic concentration of 45 mu M Ca2+ resulted in a 2-fold increase in the amplitude of the K+ current. Acidification of the cytosol topH5.5 also markedly increased NtTPK1-mediated K+ currents. These results show that NtTPK1 is a novel tonoplast K+ channel belonging to a different group from the previously characterized vacuolar channels SV, FV, and VK.

DOI： 10.1074/jbc.M708213200

イオンチャネルを標的とした植物成長調節剤

村田芳行, 森

バイオサイエンスとインダストリー 66 610 - 614 2008

Exogenous proline and glycinebetaine increase NaCl-induced ascorbate-glutathione cycle enzyme activities, and proline improves salt tolerance more than glycinebetaine in tobacco Bright Yellow-2 suspension-cultured cells. International journal

Md Anamul Hoque, Mst Nasrin Akhter Banu, Eiji Okuma, Katsumi Amako, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

Journal of plant physiology 164 ( 11 ) 1457 - 68 2007.11

Language：English Publishing type：Research paper (scientific journal)

Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system.

Papaya seed represents a rich source of biologically active isothiocyanate. International journal

Yoshimasa Nakamura, Motoko Yoshimoto, Yoshiyuki Murata, Yasuaki Shimoishi, Yumi Asai, Eun Young Park, Kenji Sato, Yasushi Nakamura

Journal of agricultural and food chemistry 55 ( 11 ) 4407 - 13 2007.5

Language：English Publishing type：Research paper (scientific journal)

In the present study, papaya (Carica papaya) seed and edible pulp were carefully separated and then the contents of benzyl isothiocyanate and the corresponding glucosinolate (benzyl glucosinolate, glucotropaeolin) quantified in each part. The papaya seed with myrosinase inactivation contained >1 mmol of benzyl glucosinolate in 100 g of fresh seed. This content is equivalent to that of Karami daikon (the hottest Japanese white radish) or that of cress. The papaya seed extract also showed a very high activity of myrosinase and, without myrosinase inactivation, produced 460 micromol of benzyl isothiocyanate in 100 g of seed. In contrast, papaya pulp contained an undetectable amount of benzyl glucosinolate and showed no significant myrosinase activity. The n-hexane extract of the papaya seed homogenate was highly effective in inhibiting superoxide generation and apoptosis induction in HL-60 cells, the activities of which are comparable to those of authentic benzyl isothiocyanate.

Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. International journal

Md Anamul Hoque, Eiji Okuma, Mst Nasrin Akhter Banu, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

Journal of plant physiology 164 ( 5 ) 553 - 61 2007.5

Language：English Publishing type：Research paper (scientific journal)

Proline and betaine accumulate in plant cells under environmental stresses including salt stress. Here, we investigated effects of proline and betaine on the growth and activities of antioxidant enzymes in tobacco Bright Yellow-2 (BY-2) culture cells in suspension under salt stress. Both proline and betaine mitigated the inhibition of growth of BY-2 cells under salt stress and the mitigating effect of proline was more than that of betaine. Salt stress significantly decreased the activities of superoxide dismutase (SOD), catalase and peroxidase in BY-2 cells. Exogenous application of proline or betaine alleviated the reduction in catalase and peroxidase activities but not SOD activity under salt stress. In addition, proline was found to be effective in alleviating the inhibition of salt stress-induced catalase and peroxidase activities in BY-2 cells. Neither proline nor betaine directly scavenged superoxide (O(2)(-)) or hydrogen peroxide (H(2)O(2)). It is concluded that exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine because of its superior ability to increase the activities of antioxidant enzymes.

The coronatine-insensitive 1 Mutation Reveals the Hormonal Signaling Interaction between Abscisic Acid and Methyl Jasmonate in Arabidopsis Guard Cells. Specific Impairment of Ion Channel Activation and Second Messenger Production International journal

Shintaro Munemasa, Kenji Oda, Megumi Watanabe-Sugimoto, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

Plant Physiology 143 ( 3 ) 1398 - 1407 2007.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

Methyl jasmonate (MeJA) elicits stomatal closing similar to abscisic acid (ABA), but whether the two compounds use similar or different signaling mechanisms in guard cells remains to be clarified. We investigated the effects of MeJA and ABA on second messenger production and ion channel activation in guard cells of wild-type Arabidopsis (Arabidopsis thaliana) and MeJA-insensitive coronatine-insensitive 1 (coi1) mutants. The coi1 mutation impaired MeJA-induced stomatal closing but not ABA-induced stomatal closing. MeJA as well as ABA induced production of reactive oxygen species (ROS) and nitric oxide (NO) in wild-type guard cells, whereas MeJA did not induce production of ROS and NO in coi1 guard cells. The experiments using an inhibitor and scavengers demonstrated that both ROS and NO are involved in MeJA-induced stomatal closing as well as ABA-induced stomatal closing. Not only ABA but also MeJA activated slow anion channels and Ca(2+) permeable cation channels in the plasma membrane of wild-type guard cell protoplasts. However, in coi1 guard cell protoplasts, MeJA did not elicit either slow anion currents or Ca(2+) permeable cation currents, but ABA activated both types of ion channels. Furthermore, to elucidate signaling interaction between ABA and MeJA in guard cells, we examined MeJA signaling in ABA-insensitive mutant ABA-insensitive 2 (abi2-1), whose ABA signal transduction cascade has some disruption downstream of ROS production and NO production. MeJA also did not induce stomatal closing but stimulated production of ROS and NO in abi2-1. These results suggest that MeJA triggers stomatal closing via a receptor distinct from the ABA receptor and that the coi1 mutation disrupts MeJA signaling upstream of the blanch point of ABA signaling and MeJA signaling in Arabidopsis guard cells.

DOI： 10.1104/pp.106.091298

Localization and function of K(+)channels from tobacco cells

Shin Hamamoto, Junichiro Marui, Ken Matsuoka, Tetsuro Mimura, Tsuyoshi Nakagawa, Yoshiyuki Murata, Yoichi Nakanishi, Masayoshi Maeshima, Isamu Yabe, Nobuyuki Uozumi

PLANT AND CELL PHYSIOLOGY 48 S122 - S122 2007

Expression and Ca^<2+> Dependency of Plasma Membrane K^+ Channels of Tobacco Suspension Cells Adapted to Salt Stress

KASUKABE Naoki, WATANABE SUGIMOTO Megumi, MATSUOKA Ken, OKUMA Eiji, OBI Ichiro, NAKAMURA Yoshimasa, SHIMOISHI Yasuaki, MURATA Yoshiyuki, KAKUTANI Tadaaki

Plant and Cell Physiology 47 ( 12 ) 1674 - 1677 2006.12

Language：English Publishing type：Research paper (scientific journal)

The expression of plasma membrane K+ channels of NaCl-adapted tobacco suspension cells and effects of extracellular Ca2+ on plasma membrane K+ channels were investigated. Reverse transcription-PCR (RT-PCR) analysis showed that expression of TORK1, which encodes a K+ channel, was much lower in NaCl-adapted cells than in NaCl-unadapted cells. The magnitude of the outward K+ currents of NaCl-adapted as well as NaCl-unadapted cells decreased with increasing extracellular Ca2+ but there is no significant difference in Ca2+ dependency of the K+ current. These analyses suggest that reduction of the number of K+ channels might cause NaCl adaptation of cells through the decrease of outward K+ currents.

CDPKs CPK6 and CPK3 function in ABA regulation of guard cell S-type anion- and Ca2+-permeable channels and stomatal closure Reviewed International journal

Izumi C. Mori, Yoshiyuki Murata, Yingzhen Yang, Shintaro Munemasa, Yong-Fei Wang, Shannon Andreoli, Herve Tiriac, Jose M. Alonso, Jeffery F. Harper, Joseph R. Ecker, June M. Kwak, Julian I. Schroeder

PLOS BIOLOGY 4 ( 10 ) 1749 - 1762 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

Abscisic acid (ABA) signal transduction has been proposed to utilize cytosolic Ca2+ in guard cell ion channel regulation. However, genetic mutants in Ca2+ sensors that impair guard cell or plant ion channel signaling responses have not been identified, and whether Ca2+-independent ABA signaling mechanisms suffice for a full response remains unclear. Calcium-dependent protein kinases (CDPKs) have been proposed to contribute to central signal transduction responses in plants. However, no Arabidopsis CDPK gene disruption mutant phenotype has been reported to date, likely due to overlapping redundancies in CDPKs. Two Arabidopsis guard cell-expressed CDPK genes, CPK3 and CPK6, showed gene disruption phenotypes. ABA and Ca2+ activation of slow-type anion channels and, interestingly, ABA activation of plasma membrane Ca2+-permeable channels were impaired in independent alleles of single and double cpk3cpk6 mutant guard cells. Furthermore, ABA- and Ca2+-induced stomatal closing were partially impaired in these cpk3cpk6 mutant alleles. However, rapid-type anion channel current activity was not affected, consistent with the partial stomatal closing response in double mutants via a proposed branched signaling network. Imposed Ca2+ oscillation experiments revealed that Ca2+-reactive stomatal closure was reduced in CDPK double mutant plants. However, long-lasting Ca2+-programmed stomatal closure was not impaired, providing genetic evidence for a functional separation of these two modes of Ca2+-induced stomatal closing. Our findings show important functions of the CPK6 and CPK3 CDPKs in guard cell ion channel regulation and provide genetic evidence for calcium sensors that transduce stomatal ABA signaling.

DOI： 10.1371/journal.pbio.0040327

Resistance imparted by vitamin C, vitamin E and vitamin B12 to the acute hepatic glycogen change in rats caused by noise.

Bei-Wei Zhu, Mei-Lan Piao, Yu Zhang, Song Han, Qing-Da An, Yoshiyuki Murata, Mikiro Tada

Acta medica Okayama 60 ( 2 ) 107 - 11 2006.4

Language：English Publishing type：Research paper (scientific journal)

The effects of vitamin C, vitamin E and vitamin B12 on the noise-induced acute change in hepatic glycogen content in rats were investigated. The exposure of rats to 95 dB and 110 dB of noise acutely reduced their hepatic glycogens. Vitamin C (ascorbic acid) and vitamin E (alpha-tocopherol) attenuated the noise-induced acute reduction in the hepatic glycogen contents. This result suggests that antioxidants could reduce the change via reactive oxygen species. Vitamin B12 (cobalamin) delayed the noise-induced change, a finding that suggests that vitamin B12 could postpone the acute change via compensating for vitamin B12 deficiency.

Apoptosis induction by dohevanil, a DHA substitutive analog of capsaicin, in MCF-7 cells. International journal

Tuoya, Naomichi Baba, Yasuaki Shimoishi, Yoshiyuki Murata, Mikiro Tada, Masamichi Koseki, Kyoya Takahata

Life sciences 78 ( 13 ) 1515 - 9 2006.2

Language：English Publishing type：Research paper (scientific journal)

Capsaicin (8-methyl-N-vanillyl-6-nonenamide), a major pungent ingredient in a variety of red peppers of the genus Capsicum, is a type of vanilloid. It has been shown to induce apoptosis in many cell types. The effects of vanilloids on apoptosis induction are thought to be correlated with the length and degree of the unsaturation of the fatty acyl chains. In this study, we compared the effect of capsaicin and its docosahexaenoic acid (DHA, C22:6) analog (we named as dohevanil) on human breast cancer MCF-7 cells, which do not express caspase-3. Dohevanil, which was synthesized from DHA and vanillylamine, has longer and highly unsaturated fatty acyl chain than capsaicin. We showed that both vanilloids exhibit effects of growth inhibition and DNA fragmentation induction in MCF-7 cells. These effects of dohevanil were more potent than capsaicin. Because these effects were inhibited by z-VAD-fmk, a broad-spectrum caspase inhibitor, the vanilloids induced the apoptosis via caspase-dependent pathway not involving caspase-3. In conclusion, dohevanil has a more potent effect on apoptosis induction in MCF-7 cells than capsaicin.

Acceleration effect of sulfides on photodegradation of carotenoids by UVA irradiation. International journal

Shin Arita, Suguru Ando, Hiroshi Hosoda, Kazushi Sakaue, Tadahiro Nagata, Yoshiyuki Murata, Yasuaki Shimoishi, Mikiro Tada

Bioscience, biotechnology, and biochemistry 69 ( 9 ) 1786 - 9 2005.9

Language：English Publishing type：Research paper (scientific journal)

The photodegradation of carotenoids by UVA irradiation in the presence of sulfides was investigated. The sulfides accelerated the photodegradation of carotenoids. A larger number of sulfur atoms of coexistent sulfides was more favorable to the acceleration effect of sulfides on the photodegradation of beta-carotene, but the alk(en)yl group of sulfides was less favorable to the acceleration effect of sulfur compounds. The acceleration effect depended on light intensity, temperature, and the initial concentrations of beta-carotene and sulfide.

The inhibitory effect of dibutyryl cyclic AMP on docosahexaenoic acid-induced apoptosis in HL-60 cells through activation of the phosphatidylinositol-3 kinase pathway.

Yoshie Miura, Yoshiyuki Murata, Kozo Utsumi, Kyoya Takahata, Mikiro Tada, Takemi Otsuki

Environmental health and preventive medicine 10 ( 4 ) 184 - 9 2005.7

Language：English Publishing type：Research paper (scientific journal)

OBJECTIVE: Docosahexaenoic acid (DHA) is known as a chemopreventive substance for cancers. Previously we reported that DHA induces apoptosis in HL-60 cells. The aim of this study was to clarify the role of phosphatidylinositol 3-kinase (PI3-kinase)/Akt signaling during DHA-induced apoptosis in HL-60 cells. METHODS: The inhibitory effects of dibutyryl cAMP (db-cAMP) or LY294002 (a specific inhibitor of the PI3-kinase/Akt pathway) on DHA-induced apoptosis in HL-60 cells were evaluated by the appearance of apoptosis, and from the activities of caspases (3 and 8), the phospholylation of Akt, and cleavage of Bid using DNA indexes, emzymatic measurement of fragmented substrates, and Western blotting, respectively. RESULTS: The pre-incubation of db-cAMP reduced the activation of caspasses (3 and 8) during the occurrence of DHA-induced apoptosis in HL-60. However, the inhibition of PI3-kinase/Akt signaling by LY294002 resulted in recovery of the caspases' activities, appearance of apoptotic cells, and cleavage of the Bid molecule when LY294002 was co-treated with db-cAMP before the occurrence of DHA-induced apoptosis in HL-60. It was also confirmed that LY294002 strongly inhibited phospholylation of Akt during db-cAMP induced-reduction of DHA-induced apoptosis in HL-60. CONCLUSION: We demonstrated that DHA-induced apoptosis was sensitive to the modulation of PI3-kinase activity by treatment with db-cAMP or LY294002. These results may provide new insights into the mechanisms of the anti-cancer activity of DHA.

DOI： 10.1007/BF02897709

Docosahexaenoic acid induces apoptosis via the Bax-independent pathway in HL-60 cells. International journal

Yoshie Miura, Keigo Takahara, Yoshiyuki Murata, Kozo Utsumi, Mikiro Tada, Kyoya Takahata

Bioscience, biotechnology, and biochemistry 68 ( 11 ) 2415 - 7 2004.11

Language：English Publishing type：Research paper (scientific journal)

We attempted to determine whether docosahexaenoic acid (DHA)-induced apoptosis is mediated via the Bax-mediated pathway in human myeloid leukemia HL-60 cells. DHA-induced apoptosis was confirmed by morphological analysis and caspase-3 activation. But, cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition (MPT), did not inhibit DHA-induced Bax translocation to mitochondria or caspase-3 activation. These data suggest that DHA can induce apoptosis via the Bax-independent pathway.

Change in allantoin and arginine contents in Dioscorea opposita 'Tsukuneimo' during the growth

Akio Ninomiya, Yoshiyuki Murata, Mikiro Tada, Yasuaki Shimoishi

Journal of the Japanese Society for Horticultural Science 73 ( 6 ) 546 - 551 2004.11

Language：English Publishing type：Research paper (scientific journal)

The ureides, allantoin and allantoic acid, are believed to play an important role in the storage and translocation of nitrogen in higher plants. Arginine is a major component in the free amino acid pool in some plants. To investigate the behavior of ureides and free amino acids, especially arginine, in developing Dioscorea opposita plants 'Tsukuneimo', their contents as well as those of water and nitrogen in leaves, stems and tubers were quantitatively analyzed. The content of allantoin in the leaves decreased after any fertilization, while that in the stems did not increase after the 1st fertilization, 96 days after planting
it significantly increased after the 2nd fertilization, 26 days later. Allantoin content in tubers remained constant during tuber development. Arginine content in leaves and stems during the growth of 'Tsukuneimo' were lower than 0.15 and 4.8 μmol·g-1FW, respectively. The time course of arginine in stems content was similar to that of allantoin. In tubers, arginine content at 170 days after planting increased to reach 14 times that at 142 days but then decreased, demonstrating that D. opposita transiently accumulates arginine in stems as well as allantoin in leaves and stems but only accumulates the latter in developing tubers.

Resistance imparted by traditional Chinese medicines to the acute change of glutamic pyruvic transaminase, alkaline phosphatase and creatine kinase activities in rat blood caused by noise. International journal

Bei-Wei Zhu, Yu-Mei Sun, Xia Yun, Song Han, Mei-Lan Piao, Yoshiyuki Murata, Mikiro Tada

Bioscience, biotechnology, and biochemistry 68 ( 5 ) 1160 - 3 2004.5

Language：English Publishing type：Research paper (scientific journal)

The activities of serum glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP) and creatine kinase (CK) in rats injected or not with the Chinese medicines, Astragali, Rhodiolae and Ligusticum, were determined after noise exposure. Noise at 95 and 105 dB significantly increased the activities of GPT, ALP and CK, and showed a dependence on the exposure time. The injection of each medicine significantly suppressed the increased enzyme activities by 95 and 105 dB noise.

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