Hirofumi Shibata, Nishitani Noriko, Yaohara Sayuri, Naokatu Arakaki, Tomihiko Higuti, Kazuyoshi Kawazoe and Kazuo Minakuchi : Simvastatin represses translocation of Pseudomonas aeruginosa across Madin-Darby canine kidney cell monolayers, The Journal of Medical Investigation : JMI, Vol.59, No.1,2, 186-191, 2012.
(要約)
Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. An increase in intestinal epithelial permeability is a characteristic of severe sepsis. Alterations in the normal barrier function of the gut mucosa may result in the translocation of microbial cells and products. On the otherhand, it has been demonstrated that statin use is associated with a lower risk of mortality from bloodstream infections. Therefore, we investigated the ability of P. aeruginosa PAO1 to translocate across the Madin-Darby canine kidney (MDCK) cell monolayers in the presence and absence of simvastatin. The bacteria readily translocated across MDCK cell monolayers after 3 h of infection irrespective of the presence or absence of the drug in the medium. However, the bacteria were less able to penetrate the MDCK monolayers in the presence of simvastatin than in its absence. A gentamicin survival assay demonstrated that simvastatin did not affect the bacteria's invasive behavior in the MDCK cells.
K Yoshikawa, M Ohtsu, N Kokudo, Hirofumi Shibata, Naokatu Arakaki, Tomihiko Higuti and T Hashimoto : Phenolic constituents from the branch of Firmiana simplex., The Japanese Journal of Pharmacognosy, Vol.64, No.2, 102-103, 2010.
(要約)
From the branch of Firmiana simplex, eleven phenolic compounds, ethyl caffeate, butyl caffeate, methyl caffeate, caffeic acid, ethyl cinnamate, kaempferol, astragalin, afzelin, quercetin, (+)-pinoresinol, and (+)-isolariciresinol were isolated. Their structures were determined by 1D and 2D nuclear magnetic resonance (NMR) and mass spectroscopy analysis. Furthermore, all the isolated compounds (1-11) were tested for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA).
Hirofumi Shibata, Tatsuro Nakano, Khasru M. Anowar Parvez, Yoshihiro Furukawa, Akio Tomoishi, Shingo Niimi, Naokatu Arakaki and Tomihiko Higuti : Triple combinations of lower and longer alky1 gallates and oxacillin improve antibiotic synergy against methicillin-resistant Staphylococcus aureus, Antimicrobial Agents and Chemotherapy, Vol.53, No.5, 2218-2220, 2009.
(要約)
Using liposome systems, we found that gallates with short alkyl chains were located in the external medium and those with longer alkyl chains were located in the surface region of lipid bilayer. Combinations of these gallates remarkably reduced oxacillin MICs against methicillin-resistant Staphylococcus aureus to below the antibiotic breakpoint (< or = 2 microg/ml).
Hitoshi Kawazoe, kyoko Takaoka, Hirofumi Shibata, Naokatu Arakaki, Tomihiko Higuti, K Negayama, Hitoshi Houchi, Koichiro Tsuchiya and Yoshiharu Takiguchi : Comparison of antibacterial activity of fluoroquinolones with their sucralfate-complexes against clinically-isolated bacteria, Journal of Health Science, Vol.55, No.5, 790-795, 2009.
(要約)
Oral fluoroquinolones are widely known to form chelate complexes with metal-containing drugs, resulting in inhibition of their intestinal absorption. However, for intestinal sterilization, the concomitant regimen may be a selective and effective strategy due to decreased absorption of fluoroquinolones result in the retainment of antibiotics at the intestine if the mixture still perpetuated antibacterial activity. Therefore, to clarify whether the mixture of fluoroquinolones and sucralfate affects their antibacterial activity or not, we conducted in vitro study. According from the checkerboard study using a microdilution method with Mueller-Hinton broth, the antibacterial activity of these fluoroquinolones-sucralfate mixtures equaled to the parent fluoroquinolones even in the presence of sucralfate at the molar ratio of [sucralfate: fluoroquinolone] was less than 166, and the minimal inhibitory concentrations for clinical isolated Escherichia coli and Pseudomonas aeruginosa strains were independent of the existence of sucralfate. These data imply that the chelated forms of each fluoroquinolone retain antibacterial activity even in the presence of the recommended therapeutic doses of sucralfate in clinical practice.
MAK Parvez, Hirofumi Shibata, Tatsuro Nakano, Shingo Niimi, Nobuo Fujii, Naokatu Arakaki and Tomihiko Higuti : No relationship exists between PBP 2a amounts expressed in different MRSA strains obtained clinically and their beta-lactam MIC values, The Journal of Medical Investigation : JMI, Vol.55, No.3-4, 246-253, 2008.
(要約)
After establishing a linear relationship between the amount of penicillin-binding protein (PBP) 2a and membrane proteins of methicillin-resistant Staphylococcus aureus (MRSA) COL by dot-blot analysis using an antibody against PBP 2a, we determined the PBP 2a quantities in membrane fractions prepared from 14 different MRSA cells. Methicillin-sensitive S. aureus ATCC 6538P was used as a quality control strain. The amounts of PBP 2a diverged among the strains, and no relationship to beta-lactam MIC values were observed in the corresponding strains.
Kazuko Yoshikawa, Naoki Kokudo, Masami Tanaka, Tatsuro Nakano, Hirofumi Shibata, Naokatu Arakaki, Tomihiko Higuti and Toshihiro Hashimoto : Novel abietane diterpenoids and aromatic compounds from Cladonia rangiferina and their antimicrobial activity against antibiotics resistant bacteria, Chemical & Pharmaceutical Bulletin, Vol.56, No.1, 89-92, 2008.
(要約)
From Cladonia rangiferina were isolated two novel abietane diterpenoids, hanagokenols A (1) and B (2). Also in this investigation, four known abitetane diterpenoids (3-6), four known labdane diterpenoids (7-10), one known isopimarane diterpenoid (11), and six known aromatic compounds were isolated. These structures were elucidated primarily through extensive NMR experiments. Hanagokenol A (1) was a unique abietane diterpene having an ether linkage between C-6 and C-18 of sugiol. Hanagokenol B (2) is also a unique secoabietane diterpene, having gamma-lactone which occurred by cleavage and subsequently oxidation between C-6/C-7 of 12-hydroxydehydroabietinol. Furthermore, all the isolated compounds (1-17) were tested for the antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE).
Naokatu Arakaki, Toshiyuki Kita, Hirofumi Shibata and Tomihiko Higuti : Cell-surface H+-ATP synthase as a potential molecular target for anti-obesity drugs, FEBS Letters, Vol.581, No.18, 3405-3409, 2007.
(要約)
Here we show that the cell-surface expression of the alpha subunit of H(+)-ATP synthase is markedly increased during adipocyte differentiation. Treatment of differentiated adipocytes with small molecule inhibitors of H(+)-ATP synthase or antibodies against alpha and beta subunits of H(+)-ATP synthase leads to a decrease in cytosolic lipid droplet accumulation. Apolipoprotein A-I, which has been shown to bind to the ectopic beta-chain of H(+)-ATP synthase and inhibit the activity of cell-surface H(+)-ATP synthase, also was found to inhibit cytosolic lipid accumulation. These results suggest that the cell-surface H(+)-ATP synthase has a previously unsuspected role in lipid metabolism in adipocytes.
Naokatu Arakaki, Takeshi Nishihama, Akira Kohda, Hiroyuki Owaki, Reika Abe, Toshiyuki Kita, Midori Suenaga, Toshiki Himeda, Masamichi Kuwajima, Hirofumi Shibata and Tomihiko Higuti : Regulation of mitochondrial morphology and cell survival by Mitogenin I and mitochondrial single-stranded DNA binding protein, Biochimica et Biophysica Acta (BBA) - General Subjects, Vol.1760, No.9, 1364-1372, 2006.
(要約)
We found that a mouse homolog of human DNA polymerase delta interacting protein 38, referred to as Mitogenin I in this paper, and mitochondrial single-stranded DNA-binding protein (mtSSB), identified as upregulated genes in the heart of mice with juvenile visceral steatosis, play a role in the regulation of mitochondrial morphology. We demonstrated that overexpression of Mitogenin I or mtSSB increased elongated or fragmented mitochondria in mouse C2C12 myoblast cells, respectively. On the other hand, the silencing of Mitogenin I or mtSSB by RNA interference led to an increase in fragmented or elongated mitochondria in the cells, respectively, suggesting that Mitogenin I and mtSSB are involved in the processes of mitochondrial fusion and fission, respectively. In addition, we showed that the silencing of Mitogenin I resulted in an increase in the number of trypan blue-positive cells and the silencing of mtSSB resulted in an enhancement of the sensitivity of the cells to apoptotic stimulation by etoposide. The present results demonstrated that these proteins play a role in cell survival.
Hiroyuki Nakagawa, Yoshihisa Takaishi, Naonobu Tanaka, Koichiro Tsuchiya, Hirofumi Shibata and Tomihiko Higuti : Chemical Constituents from the Peels of Citrus sudachi, Journal of Natural Products, Vol.69, No.8, 1177-1179, 2006.
(要約)
A methanol extract of the peels of Citrus sudachi gave five new compounds (1-5) and 27 known compounds. The structures were elucidated on the basis of spectroscopic evidence. Several of these compounds were assayed for antimicrobial activity against methicillin-resistant Staphylococcus aureus and Helicobacter pylori, and sudachitin (6) and 3'-demethoxysudachitin (7) were the most active.
Naokatu Arakaki, Takeshi Nishihama, Hiroyuki Owaki, Yoshinori Kuramoto, Midori Suenaga, Eri Miyoshi, Yuka Emoto, Hirofumi Shibata, Masayuki Shono and Tomihiko Higuti : Dynamics of mitochondria during the cell cycle, Biological & Pharmaceutical Bulletin, Vol.29, No.9, 1962-1965, 2006.
(要約)
Mitochondria are highly dynamic organelles in eukaryotic cells. Although the role of mitochondria in metabolism, ATP production and apoptosis is more widely recognized, alterations in mitochondrial morphology and abundance are also important for cellular functions. Here we investigated mitochondrial dynamics in synchronized HeLa cells in which the major stages of the cell cycle of the observed cells were resolved by staining phosphorylate histones H1 and H3, and showed that mitochondria exist as filamentous network structures throughout the cell cycle progression, changing their morphology, distribution, and abundance. The current results suggest that mitochondrial condensation occurred at prophase is required for the proper progression of mitochondrial division.
F.A. Ramos, Yoshihisa Takaishi, M. Shirotori, Y. Kawaguchi, Koichiro Tsuchiya, Hirofumi Shibata, Tomihiko Higuti, T. Tadokoro and M. Takeuchi : Antibacterial and Antioxidant Activities of Quercetin Oxidation Products from Yellow Onion (Alliu cepa) Skin, Journal of Agricultural and Food Chemistry, Vol.54, No.10, 3551-3357, 2006.
(要約)
Four new quercetin-derived oxidation products (1-4) and lunularin-4-O-beta-D-glucoside (5) were isolated from a water extract of onion (Allium cepa) skin, together with 17 other known compounds. Antibacterial assays for the isolated compounds showed that 2-(3,4-dihydroxyphenyl)-4,6-dihydroxy-2-methoxybenzofuran-3-one (1) presented selective activity against Helicobacter pylori strains and 3-(quercetin-8-yl)-2,3-epoxyflavanone (4) showed antibacterial activity against MRSA and H. pylori strains at the same time that it increased susceptibility of MRSA to beta-lactams. Evaluation of antioxidant activity against DPPH for the isolated compounds showed that the new derivative compounds (1-4) and 2,5,7,3',4'-pentahydroxy-3,4-flavandione (6) are more active than quercetin.
K Kondo, Yoshihisa Takaishi, Hirofumi Shibata and Tomihiko Higuti : ILSMRs (intensifier of β-lactam-susceptibility in methicillin-resistant Staphylococcus aureus) from Tara [Caesalpinia spinosa (Molina) Kuntze], Phytomedicine, Vol.13, No.3, 209-212, 2006.
(要約)
Four quinic acid gallates were isolated from the dried pods of Tara [Caesalpinia spinosa (Molina) Kuntze]. These compounds intensified the susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) to oxacillin. 3,4,5-Tri-O-galloylquinic acid methyl ester (2) was the most effective compound of them.
Toshimasa Ochi, Hirofumi Shibata, Tomihiko Higuti, Ko-hei Kodama, Takenori Kusumi and Yoshihisa Takaishi : Anti-Helicobacter pylori Compounds from Santalum album, Journal of Natural Products, Vol.68, No.6, 819-824, 2005.
(要約)
Six new sesquiterpenes, (Z)-2beta-hydroxy-14-hydro-beta-santalol (1), (Z)-2alpha-hydroxy-albumol (2), 2R-(Z)-campherene-2,13-diol (3), (Z)-campherene-2beta,13-diol (4), (Z)-7-hydroxynuciferol (5), and (Z)-1beta-hydroxy-2-hydrolanceol (6), together with five known compounds, (Z)-alpha-santalol (7), (Z)-beta-santalol (8), (Z)-lanceol (9), alpha-santaldiol (10), and beta-santaldiol (11), were isolated from Santalum album, by using bioassay-guided fractionation for Helicobacter pylori. The structures were determined by extensive NMR studies. The absolute configuration of compound 3 was determined by a modified Mosher method. The crude extracts as well as the isolated compounds showed antibacterial activity against H. pylori. Especially, compounds 7 and 8 have strong anti-H. pylori activities against a clarithromycin-resistant strain (TS281) as well as other strains.
Hirofumi Shibata, Kyoko Kondo, Ryo Katsuyama, Kazuyoshi Kawazoe, Youichi Sato, Kotaro Murakami, Yoshihisa Takaishi, Naokatu Arakaki and Tomihiko Higuti : Alkyl Gallates, Intensifiers of ß-Lactam Susceptibility in Methicillin-Resistant Staphylococcus aureus, Antimicrobial Agents and Chemotherapy, Vol.49, No.2, 549-555, 2005.
(要約)
We found that ethyl gallate purified from a dried pod of tara (Caesalpinia spinosa) intensified beta-lactam susceptibility in methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA strains, respectively). This compound and several known alkyl gallates were tested with MRSA and MSSA strains to gain new insights into their structural functions in relation to antimicrobial and beta-lactam susceptibility-intensifying activities. The maximum activity of alkyl gallates against MRSA and MSSA strains occurred at 1-nonyl and 1-decyl gallate, with an MIC at which 90% of the isolates tested were inhibited of 15.6 microg/ml. At concentrations lower than the MIC, alkyl gallates synergistically elevated the susceptibility of MRSA and MSSA strains to beta-lactam antibiotics. Such a synergistic activity of the alkyl gallates appears to be specific for beta-lactam antibiotics, because no significant changes were observed in the MICs of other classes of antibiotics examined in this study. The length of the alkyl chain was also associated with the modifying activity of the alkyl gallates, and the optimum length was C5 to C6. The present work clearly demonstrates that the length of the alkyl chain has a key role in the elevation of susceptibility to beta-lactam antibiotics.
Naokatu Arakaki, Ayano Toyofuku, Yuka Emoto, Tomoko Nagao, Yoshinori Kuramoto, Hirofumi Shibata and Tomihiko Higuti : Induction of G1 cell-cycle arrest in human umbilical vein endothelial cells by flavone s inhibition of the ERK cascade., Biochemistry and Cell Biology, Vol.82, No.5, 583-588, 2004.
(要約)
Dietary flavonoids have demonstrated anti-carcinogenic activity in several animal models, but their mechanisms of action have not yet been clearly established. Here we show that flavone, a parent compound of flavonoids, inhibits the proliferation, migration, and capillary tube formation of human umbilical vein endothelial cells (HUVECs). Flow cytometric analysis showed that flavone arrests the cell-cycle progression at G1 phase in HUVECs. We observed the down-regulation of the hyperphosphorylated form of retinoblastoma gene product and cyclin-dependent kinases 2 and 4 in flavone-treated cells, but it had no affect on the expression of p53 and CDK inhibitors, p21CIP/Waf1 and p27Kip. Flavone almost completely inhibited the activation of extracellular signal-regulated kinase 1 (ERK1). The present results suggest that the flavone moiety of flavonoids is required for anti-proliferative activity of flavonoids and that anticarcinogenic action of flavonoids in vivo was mediated, at least in part, by inhibiting angiogenesis.
Youichi Sato, Hirofumi Shibata, Tsutomu Arai, Akira Yamamoto, Yousuke Okimura, Naokatu Arakaki and Tomihiko Higuti : Variation in synergistic activity by flavone and its related compounds on the increased susceptibility of various strains of methicillin-resistant Staphylococcus aureus to β-lactam antibiotics, International Journal of Antimicrobial Agents, Vol.24, No.3, 226-233, 2004.
(要約)
We found that some flavonoids had a weak antibacterial effect on methicillin-resistant Staphylococcus aureus (MRSA), but that at sub-MIC concentrations they greatly increased the susceptibility of these strains to beta-lactam antibiotics. Flavone showed diverse synergistic effects on the susceptibility of MRSA to beta-lactam antibiotics. The variation of the synergistic effects of the flavones to increase the susceptibility of strains of MRSA to beta-lactam antibiotics coincided with their varying effects on growth-inhibition of these strains. Based on these findings, we have proposed a model for the mechanisms of high resistance of MRSA to beta-lactams and the massive reduction in the beta-lactams MIC caused by flavones.
Mamoru Okasaka, Yoshihisa Takaishi, Kentaro Kogure, Kenji Fukuzawa, Hirofumi Shibata, Tomihiko Higuti, Gisho Honda, Michiho Ito, Olimjon K. Kodzhimatov and Ozodbek Ashurmetov : New Stilbene Derivatives from Calligonum leucocladum, Journal of Natural Products, Vol.67, No.6, 1044-1046, 2004.
(要約)
Two new stilbene derivatives, (E)-resveratrol 3-(6' '-galloyl)-O-beta-D-glucopyranoside (1) and (E)-resveratrol 3-(4' '-acetyl)-O-beta-D-xylopyranoside (2), and five known stilbene derivatives (3-7) were isolated from the dried aerial parts of Calligonum leucocladum. Their structures were established on the basis of spectroscopic evidence. Compound 1 showed antioxidant activity and a restorative effect of the inhibition of oxacillin to oxacillin/methicillin-resistant Staphylococcus aureus.
Midori Suenaga, Masamichi Kuwajima, Toshiki Himeda, Kayoko Morokami, Teruro Matsuura, Kiyokazu Ozaki, Naokatu Arakaki, Hirofumi Shibata and Tomihiko Higuti : Identification of the up- and down-regulated genes in the heart of juvenile visceral steatosis mice, Biological & Pharmaceutical Bulletin, Vol.27, No.4, 496-503, 2004.
(要約)
Juvenile visceral steatosis (JVS) mice, novel animal models of systemic carnitine deficiency, exhibit a remarkably increased number of mitochondria in their cardiac myocytes. To date, however, there has been no reported investigation of the molecular mechanism of this increased number of mitochondria. Here, we analyzed the gene expression profile from the hearts of JVS and control mice by Affymetrix GeneChip analysis representing 34323 genes. We found that 176 genes, containing 93 known genes and 83 novel genes, were up-regulated in JVS mice compared with control mice, and 167 genes, containing 67 known genes and 100 novel genes, were down-regulated in JVS mice compared with control mice. We found several interesting molecular aspects that have not yet been identified in the hearts of JVS mice, including down-regulation of a number of ion channels and up-regulation of regulators involved in cell cycle progression. This genome-wide analysis should contribute to a greater understanding of the molecular mechanism of mitochondrial biogenesis in the heart of JVS mouse and provide a strategy for identifying novel genes involved not only in mitochondrial biogenesis but also in cardiac hypertrophy.
Youichi Sato, Hirofumi Shibata, Naokatu Arakaki and Tomihiko Higuti : 6,7-dihydroxyflavone dramatically intensifies the susceptibility of methicillin-resistant or -sensitive Staphylococcus aureus to beta-lactams., Antimicrobial Agents and Chemotherapy, Vol.48, No.4, 1357-1360, 2004.
(要約)
We have demonstrated that 6,7-dihydroxyflavone by itself has only a weak antibacterial effect on methicillin-resistant Staphylococcus aureus (MRSA) but that at concentrations less than MIC it synergistically elevates the susceptibility of clinically isolated MRSA and methicillin-sensitive S. aureus strains to beta-lactam antibiotics from 8- to 32,800-fold.
Naokatu Arakaki, Tomoko Nagao, Rie NIki, Ayako Toyofuku, Hiroaki Tanaka, Yoshinori Kuramoto, Yuka Emoto, Hirofumi Shibata, Koji Magota and Tomihiko Higuti : Possible role of cell surface H+-ATP synthase in the extracellular ATP synthesis and proliferation of human umbilical vein endothelial cells, Molecular Cancer Research : MCR, Vol.1, No.13, 931-939, 2003.
(要約)
Extracellular ATP synthesis on human umbilical vein endothelial cells (HUVECs) was examined, and it was found that HUVECs possess high ATP synthesis activity on the cell surface. Extracellular ATP generation was detected within 5 s after addition of ADP and inorganic phosphate and reached a maximal level at 15 s. This type of ATP synthesis was almost completely inhibited by mitochondrial H(+)-ATP synthase inhibitors (e.g., efrapeptins, resveratrol, and piceatannol), which target the F(1) catalytic domain. Oligomycin and carbonyl cyanide m-chlorophenylhydrazone, but not potassium cyanide, also inhibited extracellular ATP synthesis on HUVECs, suggesting that cell surface ATP synthase employs the transmembrane electrochemical potential difference of protons to synthesize ATP as well as mitochondrial H(+)-ATP synthase. The F(1)-targeting H(+)-ATP synthase inhibitors markedly inhibited the proliferation of HUVECs, but intracellular ATP levels in HUVECs treated with these inhibitors were only slightly affected, as shown by comparison with the control cells. Interestingly, piceatannol inhibited only partially the activation of Syk (a nonreceptor tyrosine kinase), which has been shown to play a role in a number of endothelial cell functions, including cell growth and migration. These findings suggest that H(+)-ATP synthase-like molecules on the surface of HUVECs play an important role not only in extracellular ATP synthesis but also in the proliferation of HUVECs. The present results demonstrate that the use of small molecular H(+)-ATP synthase inhibitors targeting the F(1) catalytic domain may lead to significant advances in potential antiangiogenic cancer therapies.
Flavone and its derivatives had very weak antibacterial effects on niethicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus, but dramatically intensified MRSA's susceptibility to β-lactams. We named these compounds "ILSMR (intensifier of β-lactam-susceptibility in MRSA)." We also found discrepancies among MRSA strains in their responses to flavone; some strains showed phenotypic susceptibility to methicillin while others showed phenotypic resistance to it. To understand the mechanism underlying this discrepancy, we characterized 20 MRSA strains in detail, analyzed their conventional and molecular typings, and examined each strain's resistance to β-lactams, with COL serving as a reference. Neither SCCmec typing nor coagulase typing explained the diverse effects of flavone on the β-lactam MICs of these strains. Likewise, changes in pulsed-field gel electrophoresis (PFGE) type were not associated with the profiles of ILSMR effects. However, the present observations suggest that the ILSMR effects on MRSA is strain-specific, and that this effect depends on an as-yet unknown mechanism that is essential for the expression of the phenotype conferring β-lactam resistance to MRSA strains, independently of an interaction with the mecA-encoded penicillin-binding protein 2a or with the β-lactamase.
Kazuyoshi Kawazoe, Yoshiko Tsubouchi, Norasyikin Abdullah, Yoshihisa Takaishi, Hirofumi Shibata, Tomihiko Higuti, Hitoshi Hori and Makoto Ogawa : Sesquiterpenoids from Artemisia gilvescens and an Anti-MRSA Compound, Journal of Natural Products, Vol.66, No.4, 538-539, 2003.
(要約)
A new secoguaianolide sesquiterpene (1) was isolated along with its three stereoisomers (2-4) from the nonmedicinal plant Artemisia gilvescens. The structure of 1 was elucidated to be (4S,5S)-dihydro-5-[(1R,2S)-2-hydroxy-2-methyl-5-oxo-3-cyclopenten-1-yl]-3-methylene-4-(3-oxobutyl)-2(3H)-furanone on the basis of 2D NMR and other spectroscopic evidence. Five known sesquiterpenoids were also isolated from this plant, and one of them (5) showed activity against methicillin-resistant Staphylococcus aureus (MRSA).
Midori Suenaga, Naokatu Arakaki, Kayoko Morokami, Toshiki Himeda, Hirofumi Shibata, Masamichi Kuwajima and Tomihiko Higuti : Functional disorders of the oxidative phosphorylation system in the heart mitochondria of mice with juvenile visceral steatosis, Biological & Pharmaceutical Bulletin, Vol.26, No.3, 289-294, 2003.
(要約)
Mice with juvenile visceral steatosis (JVS) develop remarkable cardiac hypertrophy and exhibit an increased number of mitochondria in their heart. However, the biochemical characteristics and physiological functions of these mitochondria cardiac are little known. Here we show that the respiratory activities at state 3 with glutamate plus malate or succinate in the heart mitochondria of JVS mice were greatly decreased to 47% or 77%, respectively, compared with those of control mice. The contents of cytochromes a+a_3, b, and c+c_1 in the heart mitochondria of these mice were also decreased, to 51%, 45%, and 79%, respectively, of those of the control mice. Oligomycin-sensitive ATPase activitiy in these mitochondria, however, was increased to about 2 times over that of the control mice. Surprisingly, the ATP-Pi exchange activity of the heart mitochondria of JVS mice was greatly decreased, to 35% of that of control mice. On the other hand, the expression levels of 2 subunits of H^+-ATP synthase, I. E. , coupling factor 6 and α subunit, in heart mitochondria from control and JVS mice were almost the same. These results indicate that the coordinate regulation of mitochondrial proliferation and gene expression for components of the oxidative phosphorylation system was markedly defective in the heart of JVS mice. Our current results also suggest the presence of a novel regulatory mechanisms of ATP synthase activities in the heart.
Michiko Matsuhisa, Yasuhiro Shikishima, Yoshihisa Takaishi, Gisho Honda, Michiho Ito, Yoshio Takeda, Hirofumi Shibata, Tomihiko Higuti, Olimjon K. Kodzhimatov and Ozodbek Ashurmetov : Benzoylphloroglucinol Derivatives from Hypericum scabrum, Journal of Natural Products, Vol.65, No.3, 290-294, 2002.
(要約)
Nine new polyprenylated benzoylphloroglucinol derivatives, hyperibones A-I (1-9), were isolated from the aerial parts of the Uzbekistan medicinal plant Hypericum scabrum. Their structures were determined mainly on the basis of spectroscopic evidence (2D NMR and HRMS). Compounds 1, 2, and 4 showed mild in vitro antibacterial activity against methicillin-resistance Staphylococus aureus (MRSA) and methicillin-sensitive Staphylococus aureus (MSSA).
Akira Shibata, A. Yorimitsu, H. Ikema, K. Minami, Satoru Ueno, E. Muneyuki and Tomihiko Higuti : Photocurrent of purple membrane adsorbed onto a thin polymer film, --- action characteristics of the local anesthetics ---, Colloids and Surfaces B:Biointerfaces, Vol.23, No.4, 375-382, 2002.
(キーワード)
Oriented purple membrane / Photocurrent / Local anesthetic / Binding site
Tomihiko Higuti, H. Shibata, Y. Sato, C. Arai, C. Shirakata and N. Arakaki : Dramatic Induction by Flavone and its derivatives of Susceptibility to β-Lactam Antibiotics in Methicillin-Resistant Staphylococcus Aureus, Polyphenols Communications, 127-128, 2002.
29.
Kimiko Tamemoto, Yoshihisa Takaishi, Bei Chen, Kazuyoshi Kawazoe, Hirofumi Shibata, Tomihiko Higuti, Gisho Honda, Michiho Ito, Yoshio Takeda, Olimjon K. Kodzhimatov and Ozodbek Ashurmetov : Sesquiterpenoids from the fruits of Ferula kuhistanica and antibacterial activity of the constituents of F. kuhistanica, Phytochemistry, Vol.58, No.5, 763-767, 2001.
(要約)
Ethyl acetate extracts of the air-dried fruits of Ferula kuhistanica afforded three daucane esters: kuhistanicaol H, I and J, together with nine other known compounds. Their structures were established on the basis of spectroscopic evidence. Isolated compounds in this paper and previously reported compounds from the roots and stems of F. kuhistanica were tested for antibacterial activity. Some of them were selectively toxic against Gram-positive bacteria, including methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA).
Akira Shibata, H. Ikema, Satoru Ueno, E. Muneyuki and Tomihiko Higuti : Alkane derivative-bacteriorhodopsin interaction: proton transport and protein structure, Colloids and Surfaces B:Biointerfaces, Vol.22, No.1, 31-38, 2001.
(要約)
The effects of alkane derivatives, 1-alcohols (ROH), aliphatic amine hydrochlorides (RNH(2).HCl) and sodium aliphatic carboxylates (ROONa), on the proton pumping activity of bacteriorhodopsin (bR) in a purple membrane have been examined. Photocurrents in bR in the purple membrane adsorbed onto polyester thin film were recorded before and after exposure to these test substances. The peak photocurrent in bR was reversibly suppressed by each substance. From the dose-response curve, the concentrations required to reduce the peak capacitive current by 50% were determined for each homolog and then the standard free energies per CH(2) for the adsorption of the alkane derivatives to the site of action were estimated: -3.13 kJ mol(-1) for ROH, -3.05 kJ mol(-1) for RNH(3)(+), and -2.95 kJ mol(-1) for ROO(-). The proton pumping activity of bR was mainly suppressed by the hydrophobic interaction with the additive. The relative potencies of the functional groups of the alkane derivatives were almost comparable between 1-octanol (C(8)OH) and octylamine hydrochloride (C(8)NH(3)(+)) and about 10 times less effective for sodium octanoate (C(8)OO(-)) than for others. The addition of C(8)OH or C(8)OO(-) changed the absorption spectra of bR with a maximum at 560 nm to the spectra of the intermediate state with a maximum at 480 nm, while the C(8)NH(3)(+) decreased the intensity of the 560 nm band only with no blue-shift by the 480 nm band. We conclude that the action of the alkane derivatives is nonspecific and directed to all organized purple membrane structures and that the binding sites of the ROH and ROO(-) are different from that of RNH(3)(+).
Naokatu Arakaki, Yumiko Ueyama, Mayumi Hirose, Toshiki Himeda, Hirofumi Shibata, Shiroh Futaki, Kouki Kitagawa and Tomihiko Higuti : Stoichiometry of subunit e in rat liver mitochondrial H+-ATP synthase and membrane topology of its putative Ca2+-dependent regulatory region, Biochimica et Biophysica Acta (BBA) - Bioenergetics, Vol.1504, No.2-3, 220-228, 2001.
(要約)
Previous studies have revealed that residues 34-65 of subunit e of mitochondrial H(+)-ATP synthase are homologous with the Ca(2+)-dependent tropomysin-binding region for troponin T and have suggested that subunit e could be involved in the Ca(2+)-dependent regulation of H(+)-ATP synthase activity. In this study, we determined the content of subunit e in H(+)-ATP synthase purified from rat liver mitochondria, and we also investigated the membrane topology of a putative Ca(2+)-dependent regulatory region of subunit e using an antibody against peptide corresponding to residues 34-65 of subunit e. Quantitative immunoblot analysis of subunit e in the purified H(+)-ATP synthase revealed that 1 mol of H(+)-ATP synthase contained 2 mol of subunit e. The ATPase activity of mitoplasts, in which the C-side of F(0) is present on the outer surface of the inner membrane, was significantly stimulated by the addition of the antibody, while the ATPase activity of submitochondrial particles and purified H(+)-ATP synthase was not stimulated. The antibody bound to mitoplasts but not to submitochondrial particles. These results suggest that the putative Ca(2+)-dependent regulatory region of subunit e is exposed on the surface of the C-side of F(0) and that subunit e is involved in the regulation of mitochondrial H(+)-ATP synthase activity probably via its putative Ca(2+)-dependent regulatory region.
A. Shibata, K. Yamada, H. Ikema, Satoru Ueno, E. Muneyuki and Tomihiko Higuti : Photocurrent of purple membrane adsorbed onto a thin solid film: effects of monovalent and divalent ions, Studies in Surface Science and Catalysis, Vol.132, 635-638, 2001.
Kazuyoshi Kawazoe, Aki Yutani, Kimiko Tamemoto, Shuko Yuasa, Hirofumi Shibata, Tomihiko Higuti and Yoshihisa Takaishi : Phenylnaphthalene Compounds from the Subterranean Part of Vitex rotundifolia and Their Antibacterial Activity Against Methicillin-Resistant Staphylococcus aureus, Journal of Natural Products, Vol.64, No.5, 588-591, 2001.
(要約)
A careful investigation of the subterranean part of Vitex rotundifolia has shown that this plant contains five novel lignans having a 1-phenylnaphthalene-type skeleton together with four known lignans. These structures were elucidated on the basis of spectroscopic data. Furthermore, some of the isolated compounds showed antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).
Toshiki Himeda, Kayoko Morokami, Naokatu Arakaki, Hirofumi Shibata and Tomihiko Higuti : Synchronized transcriptional gene expression of H+-ATP synthase subunits in different tissues of Fischer 344 rats of different ages, European Journal of Biochemistry, Vol.267, No.23, 6938-6942, 2000.
(要約)
Little is known about the relationship between the stoichiometry of polypeptides of multisubunit enzyme complexes and the absolute amount of each transcript of the complexes in mammalian tissues. Here we showed that the absolute amounts of the transcripts of most subunits of rat H+-ATP synthase examined greatly differed in the different tissues, showing the following hierarchy of tissue-specificity: heart > kidney > brain approximately liver. However, surprisingly, there was no difference in the expression pattern of these in terms of the molar ratio of each transcript, indicating a nearly similar stoichiometric expression pattern irrespective of tissue or age of the rat. Therefore, the present finding clearly indicates that most of the transcripts of the 16 subunits of rat H+-ATP synthase were concertedly and synchronously expressed, having a constant expression pattern of the transcripts, irrespective of tissue or age of the rats. This is the first report of the absolute amounts of the transcripts of this multisubunit enzyme.
Youichi Sato, Shiho Suzaki, Takako Nishikawa, Masaru Kihara, Hirofumi Shibata and Tomihiko Higuti : Phytochemical flavones isolated from Scutellaria barbata and antibacterial activity against methicillin-resistant Staphylococcus aureus., Journal of Ethnopharmacology, Vol.72, No.3, 483-488, 2000.
(要約)
A crude extract prepared from Scutellaria barbata D. Don (Lamiaceae) was analyzed in the effort to discover antibacterial compounds against high-level strains of methicillin-resistant Staphylococcus aureus (MRSA). Apigenin and luteolin were isolated from the plant as active constituents against the bacteria. These flavonoid congeners were selectively toxic to S. aureus, including the MRSA and methicillin-sensitive S. aureus strains.
Youichi Sato, H Oketani, T Yamada, K Singyouchi, T Ohtsubo, Masaru Kihara, Hirofumi Shibata and Tomihiko Higuti : A Xanthanolide with Potent Antibacterial Activity against Methicillin-resistant Staphylococcus aureus., The Journal of Pharmacy and Pharmacology, Vol.49, 1042-1044, 1997.
37.
Hidehiro Sangawa, Toshiki Himeda, Hirofumi Shibata and Tomihiko Higuti : Gene expression of subunit c(P1), subunit c(P2), and oligomycin sensitivity-conferring protein may play a key role in biogenesis of H+-ATP synthase in various rat tissues, The Journal of Biological Chemistry, Vol.272, No.9, 6034-6037, 1997.
(要約)
Mammalian H+-ATP synthase is a supramolecule composed of at least 14 subunits that have a constant stoichiometry. Nevertheless the coordinate regulation of the gene expressions of various subunits remains obscure. To clarify the coordinate transcriptional regulatory system of mammalian H+-ATP synthase, we determined the absolute amount of nine species of mRNAs for eight nuclear-encoded subunits of H+-ATP synthase in different tissues of 8-week-old rats by use of the synthetic mRNAs and 32P-labeled DNA probes for each mRNA. Our quantitative analyses of the transcripts of H+-ATP synthase revealed that nine species of the subunits in different tissues of 8-week-old rats were divisible into two groups: a high transcript gene (HTG) group (beta-subunit, subunit b, subunit d, subunit e, and Factor 6) and a low transcript gene (LTG) group (subunit c(P1), subunit c(P2), IF1, and oligomycin sensitivity-conferring protein). The transcription step of LTG could constitute a bottleneck in the biogenesis of H+-ATP synthase. Thus, the transcriptional regulatory system of the LTG may play a key role in the biogenesis of mammalian H+-ATP synthase. The HTG were transcribed in a tissue-specific manner that corresponds with energy demand in the tissues. However, there was no tissue specificity in subunit c(P2). Furthermore, the tissue specificity of the transcript of IF1 differed substantially from that of HTG, suggesting that it could be crucial in the protection of mitochondrial membrane under abnormal conditions.
Youichi Sato, H Oketani, K Singyouchi, T Ohtubo, Masaru Kihara, Hirofumi Shibata and Tomihiko Higuti : Extraction and Purification of Effective Antimicrobial Constituents of Terminalia chebula RETS. against Methicillin-Resistant Staphylococcus aureus., Biological & Pharmaceutical Bulletin, Vol.20, 401-404, 1997.
39.
Mark Prescott, Tomihiko Higuti, Phillip Nagley and Rodney J. Devenish : The Functional Expression of a Rat cDNA Encoding OSCP in the Yeast Saccharomyces cerevisiae, Biochemical and Biophysical Research Communications, Vol.207, No.3, 943-949, 1995.
40.
Junji Ezaki, Leonhard S. Wolfe, Tomihiko Higuti, Kazumi Ishidoh and Eiki Kominami : Specific Delay of Degradation of Mitochondrial ATP Synthase Subunit c in Late Infantile Neuronal Ceroid Lipofuscinosis (Batten Disease), Journal of Neurochemistry, Vol.64, No.2, 733-741, 1995.
41.
Tomisaburo Kakuno, Kazuo Hosoi, Tomihiko Higuti and Takekazu Horio : Electron and proton transports in Rhodospirillum rubrum chromatophores, The Journal of Biochemistry, Vol.74, No.6, 1193-1203, 1973.
総説・解説:
1.
Tomihiko Higuti, Toshiki Himeda, Yuko Koto and Kayoko Morokami : Concerted gene expression and master factor in molecular architecture of mammalian H+-ATP synthase, In Molecular Superstructure Design and Creation (Kajiyama, T. ed.), 362-366, 1998.
国際会議:
1.
Kawano Wataru, Hirofumi Shibata, Hikichi Kaori, Masanori Higuti, Kazuyoshi Kawazoe, Kazuo Minakuchi and Tomihiko Higuti : Antiviral Effect of Octyl Gallate, 11th Western Pacific Congress on Chemotherapy and Infectious Diseases, 0, Taipei, Dec. 2008.
Toshiki Himeda, Kayoko Morokami, Naokatu Arakaki, Hirofumi Shibata and Tomihiko Higuti : Synchronized transcriptional gene expression of H+-ATP synthase subunits in different tissues of Fischer 344 rats of different ages, The First International Symposium on Molecular Synchronization for Design of New Materials System, Tokyo, Sep. 2000.
4.
Toshiki Himeda, Kayoko Morokami, Hidehiro Sangawa, Hirofumi Shibata and Tomihiko Higuti : Gene expression of subunit c(P1), subunit c(P2), and oligomycin sensitivity conferring protein may play a key role in biogenesis of ATP synthase in various rat tissues, 17th International Congress of Biochemistry and Molecular Biology, San Francisco, Aug. 1997.
5.
Hidehiro Sangawa, Toshiki Himeda and Tomihiko Higuti : Age-Related Changes of Transcriptional Regulatory Systems of H+-ATP Synthase Subunits in Rat Tissues, 12th International Symposium of Federation of Asian and Oceanian Biochemists and Molecular Biologists. Gene Regulation of Biological Functions, Tokushima, Jul. 1996.
MAK Parvez, Hirofumi Shibata and Tomihiko Higuti : No relationship exists between PBP 2a amounts expressed in MRSA and -lactams MIC-values, 第81回日本細菌学会総会, Mar. 2008.
MAK Anowar Khasru Parvez Md., Hirofumi Shibata, T Nakano, N Eguchi, H Aoi, Y Itoh and Tomihiko Higuti : Action mechanism of ILSMRs in MRSA, 第52回ブドウ球菌研究会, Sep. 2007.
Tomihiko Higuti, Hirofumi Shibata, Youichi Sato, Yoshihisa Takaishi, Kazuyoshi Kawazoe and Kotaro Murakami : Medical composition for treating infection with drugresistant Staphylococcus aureus, PIXXD2 WO 2004066992 A1 20040812 CAN 141:167738 AN 2004:648378 CAPLUS (Apr. 2004).