Tanaka R

References (9)

Title : Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide - Zahir_2021_Life.(Basel)_11_
Author(s) : Zahir L , Kida T , Tanaka R , Nakayama Y , Shiono T , Kawasaki N , Yamano N , Nakayama A
Ref : Life (Basel) , 11 : , 2021
Abstract : An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than -40 degreesC and melting temperature at 130-152 degreesC. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 degreesC. The triblock copolymers and PMPG homopolymer were found to show 9-15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.
ESTHER : Zahir_2021_Life.(Basel)_11_
PubMedSearch : Zahir_2021_Life.(Basel)_11_
PubMedID: 33445658

Title : Subcellular localization of chlorophyllase2 reveals it is not involved in chlorophyll degradation during senescence in Arabidopsis thaliana - Hu_2020_Plant.Sci_290_110314
Author(s) : Hu X , Jia T , Hortensteiner S , Tanaka A , Tanaka R
Ref : Plant Sci , 290 :110314 , 2020
Abstract : Chlorophyllase (CLH), which catalyzes the release of the phytol chain from chlorophyll (Chl), has been long considered to catalyze the first step of Chl degradation. Arabidopsis contains two isoforms of CLH (CLH1 and CLH2), and CLH1 was previously demonstrated to be localized in tonoplast and endoplasmic reticulum, and not be involved in Chl degradation. In contrast, CLH2 possesses a predicted signal-peptide for chloroplast localization, and phylogenetic analysis of CLHs in Arabidopsis and other species also indicate that CLH2 forms a different clade than CLH1. Therefore, the possibility remains that CLH2 is involved in the breakdown of Chl. In the current study, clh mutants lacking CLH2 or both CLH isoforms were analyzed after the induction of senescence. Results indicated that the clh knockout lines were still able to degrade Chl at the same rate as wild-type plants. Transgenic Arabidopsis plants were generated that constitutively expressed either CLH2 or CLH2 fused to a yellow fluorescent protein (YFP). Observations made using confocal microscopy indicated that CLH2-YFP was located external to chloroplasts. Additionally, in overexpression plants, CLH2 was enriched in tonoplast and endoplasmic reticulum fractions following membrane fractionation. Based on the collective data, we conclude that CLH2 is not involved in Chl breakdown during senescence in Arabidopsis.
ESTHER : Hu_2020_Plant.Sci_290_110314
PubMedSearch : Hu_2020_Plant.Sci_290_110314
PubMedID: 31779896

Title : Reexamination of chlorophyllase function implies its involvement in defense against chewing herbivores - Hu_2015_Plant.Physiol_167_660
Author(s) : Hu X , Makita S , Schelbert S , Sano S , Ochiai M , Tsuchiya T , Hasegawa SF , Hortensteiner S , Tanaka A , Tanaka R
Ref : Plant Physiol , 167 :660 , 2015
Abstract : Chlorophyllase (CLH) is a common plant enzyme that catalyzes the hydrolysis of chlorophyll to form chlorophyllide, a more hydrophilic derivative. For more than a century, the biological role of CLH has been controversial, although this enzyme has been often considered to catalyze chlorophyll catabolism during stress-induced chlorophyll breakdown. In this study, we found that the absence of CLH does not affect chlorophyll breakdown in intact leaf tissue in the absence or the presence of methyl-jasmonate, which is known to enhance stress-induced chlorophyll breakdown. Fractionation of cellular membranes shows that Arabidopsis (Arabidopsis thaliana) CLH is located in the endoplasmic reticulum and the tonoplast of intact plant cells. These results indicate that CLH is not involved in endogenous chlorophyll catabolism. Instead, we found that CLH promotes chlorophyllide formation upon disruption of leaf cells, or when it is artificially mistargeted to the chloroplast. These results indicate that CLH is responsible for chlorophyllide formation after the collapse of cells, which led us to hypothesize that chlorophyllide formation might be a process of defense against chewing herbivores. We found that Arabidopsis leaves with genetically enhanced CLH activity exhibit toxicity when fed to Spodoptera litura larvae, an insect herbivore. In addition, purified chlorophyllide partially suppresses the growth of the larvae. Taken together, these results support the presence of a unique binary defense system against insect herbivores involving chlorophyll and CLH. Potential mechanisms of chlorophyllide action for defense are discussed.
ESTHER : Hu_2015_Plant.Physiol_167_660
PubMedSearch : Hu_2015_Plant.Physiol_167_660
PubMedID: 25583926

Title : Specialist versus generalist life histories and nucleotide diversity in Caenorhabditis nematodes - Li_2014_Proc.Biol.Sci_281_20132858
Author(s) : Li S , Jovelin R , Yoshiga T , Tanaka R , Cutter AD
Ref : Proc Biol Sci , 281 :20132858 , 2014
Abstract : Species with broad ecological amplitudes with respect to a key focal resource, niche generalists, should maintain larger and more connected populations than niche specialists, leading to the prediction that nucleotide diversity will be lower and more subdivided in specialists relative to their generalist relatives. This logic describes the specialist-generalist variation hypothesis (SGVH). Some outbreeding species of Caenorhabditis nematodes use a variety of invertebrate dispersal vectors and have high molecular diversity. By contrast, Caenorhabditis japonica lives in a strict association and synchronized life cycle with its dispersal host, the shield bug Parastrachia japonensis, itself a diet specialist. Here, we characterize sequence variation for 20 nuclear loci to investigate how C. japonica's life history shapes nucleotide diversity. We find that C. japonica has more than threefold lower polymorphism than other outbreeding Caenorhabditis species, but that local populations are not genetically disconnected. Coupled with its restricted range, we propose that its specialist host association contributes to a smaller effective population size and lower genetic variation than host generalist Caenorhabditis species with outbreeding reproductive modes. A literature survey of diverse organisms provides broader support for the SGVH. These findings encourage further testing of ecological and evolutionary hypotheses with comparative population genetics in Caenorhabditis and other taxa.
ESTHER : Li_2014_Proc.Biol.Sci_281_20132858
PubMedSearch : Li_2014_Proc.Biol.Sci_281_20132858
PubMedID: 24403340
Gene_locus related to this paper: caeja-h2wj36

Title : Anagliptin, a DPP-4 inhibitor, suppresses proliferation of vascular smooth muscles and monocyte inflammatory reaction and attenuates atherosclerosis in male apo E-deficient mice - Ervinna_2013_Endocrinology_154_1260
Author(s) : Ervinna N , Mita T , Yasunari E , Azuma K , Tanaka R , Fujimura S , Sukmawati D , Nomiyama T , Kanazawa A , Kawamori R , Fujitani Y , Watada H
Ref : Endocrinology , 154 :1260 , 2013
Abstract : Dipeptyl peptidase-4 (DPP-4) inhibitors modulate the progression of atherosclerosis. To gain insights into their mechanism of action, 9-wk-old male apolipoprotein E (apoE)-deficient mice were fed a DPP-4 inhibitor, anagliptin-containing diet. The effects of anagliptin were investigated in, a monocyte cell line, human THP-1 cells, and rat smooth muscle cells (SMCs). Treatment with anagliptin for 16 wk significantly reduced accumulation of monocytes and macrophages in the vascular wall, SMC content in plaque areas, and oil red O-stained area around the aortic valve without affecting glucose tolerance or body weight. Serum DPP-4 concentrations were significantly higher in apoE-deficient mice than control mice, and the levels increased with aging, suggesting the involvement of DPP-4 in the progression of atherosclerosis. Indeed, soluble DPP-4 augmented cultured SMC proliferation, and anagliptin suppressed the proliferation by inhibiting ERK phosphorylation. In THP-1 cells, anagliptin reduced lipopolysaccharide-induced TNF-alpha production with inhibiting ERK phosphorylation and nuclear translocation of nuclear factor-kappaB. Quantitative analysis also showed that anagliptin reduced the area of atherosclerotic lesion in apoE-deficient mice. These results indicated that the anti-atherosclerotic effect of anagliptin is mediated, at least in part, through its direct inhibition of SMC proliferation and inflammatory reaction of monocytes.
ESTHER : Ervinna_2013_Endocrinology_154_1260
PubMedSearch : Ervinna_2013_Endocrinology_154_1260
PubMedID: 23337530

Title : Molecular Cloning and Transcript Expression of Genes Encoding Two Types of Lipoprotein Lipase in the Ovary of Cutthroat Trout, Oncorhynchus clarki - Ryu_2013_Zoolog.Sci_30_224
Author(s) : Ryu YW , Tanaka R , Kasahara A , Ito Y , Hiramatsu N , Todo T , Sullivan CV , Hara A
Ref : Zoolog Sci , 30 :224 , 2013
Abstract : Large amounts of neutral lipids (NLs) are stored as lipid droplets in the ooplasm of fish oocytes, providing an essential energy resource for developing embryos and larvae. However, little is known about the origin of such lipids or about mechanisms underlying their uptake and accumulation in oocytes. We have proposed a model for this lipidation of teleost oocytes, as follows: very low density lipoprotein (Vldl) is metabolized by lipoprotein lipase (Lpl) outside and/or inside of the oocyte and the resulting fatty acids (FAs) are then utilized for de novo biosynthesis of NLs. As a first step toward verification of this model, cDNAs for genes encoding two types of Lpl, lpl and lpl2, were cloned from the ovary of cutthroat trout, Oncorhynchus clarki. Examination of Lpl polypeptide sequences deduced from the cDNAs revealed features similar to LPLs/Lpls in other species, including several conserved structural and functional domains. Both types of lpl mRNA were highly expressed in lipid storage tissues (e.g., adipose tissue, muscle, and ovary) and were predominantly expressed in the granulosa cells of ovarian follicles. Ovarian lpl1 mRNA levels showed a remarkable peak in April (early oocyte lipid droplet stage) and then decreased to low values sustained until November (mid-vitellogenesis), after which time a small peak in lpl1 gene expression was observed in December (late vitellogenesis). The mRNA levels of lpl2 also were elevated in April and were highest in June (late lipid droplet stage), but did not show other pronounced changes. These results suggest that, in the cutthroat trout, Vldl is metabolized by the action of Lpls in the granulosa cell layer to generate free FAs for uptake and biosynthesis of neutral lipids by growing oocytes.
ESTHER : Ryu_2013_Zoolog.Sci_30_224
PubMedSearch : Ryu_2013_Zoolog.Sci_30_224
PubMedID: 23480383
Gene_locus related to this paper: oncmy-a0a060vy20 , oncmy-a0a060y788

Title : Interfacial behavior of fatty-acylated sericin prepared by lipase-catalyzed solid-phase synthesis - Ogino_2006_Biosci.Biotechnol.Biochem_70_66
Author(s) : Ogino M , Tanaka R , Hattori M , Yoshida T , Yokote Y , Takahashi K
Ref : Biosci Biotechnol Biochem , 70 :66 , 2006
Abstract : Fatty-acylated sericin {1:0.7 molar ratio of sericin (Mr 18,700) to oleic acid} was prepared by lipase-catalyzed solid-phase synthesis in n-hexane containing oleic acid to endow sericin with interfacial properties. Acylation with oleic acid was confirmed by 1H-NMR. The fatty-acylated sericin exhibited superior emulsifying activity index and emulsion stability in the presence of 0-0.5 M NaCl, in a temperature range of 30-80 degrees C and pH range of 2-7, as compared with the control sericin. The fatty-acylated sericin (1:0.4 molar ratio) prepared by using low-molecular-weight sericin (Mr 5,000) also exhibited superior emulsifying properties. The affinity of the fatty-acylated sericin to a hydrophobic surface as evaluated by a biomolecular interaction analyzer was about twice as much as that of the control sericin. The fatty-acylated sericin showed retarded water vaporization, similar to the control sericin, indicating good retention of moistness, and was adsorbed four times as much to defatted wool with little desorption as compared with the control sericin.
ESTHER : Ogino_2006_Biosci.Biotechnol.Biochem_70_66
PubMedSearch : Ogino_2006_Biosci.Biotechnol.Biochem_70_66
PubMedID: 16428822

Title : Plasma endotoxin and serum cytokine levels in patients with alcoholic hepatitis: relation to severity of liver disturbance - Fujimoto_2000_Alcohol.Clin.Exp.Res_24_48S
Author(s) : Fujimoto M , Uemura M , Nakatani Y , Tsujita S , Hoppo K , Tamagawa T , Kitano H , Kikukawa M , Ann T , Ishii Y , Kojima H , Sakurai S , Tanaka R , Namisaki T , Noguchi R , Higashino T , Kikuchi E , Nishimura K , Takaya A , Fukui H
Ref : Alcohol Clin Exp Res , 24 :48S , 2000
Abstract : BACKGROUND: Endotoxin plays an important role in the initiation and aggravation of alcoholic liver disease. In this study, we evaluated plasma endotoxin levels and serum concentrations of cytokines and lipopolysaccharide binding protein (LBP) during the acute and recovery phase of patients with alcoholic hepatitis; we also explored the prognostic factors associated with a fatal outcome.
METHODS: Fourteen patients, consisting of eight patients with alcoholic hepatitis (AH), five cirrhotics with superimposed AH (LC+AH), and one patient with severe alcoholic hepatitis (SAH), were studied. Among these, two with LC+AH died of hepatic failure.
RESULTS: Plasma endotoxin levels in the acute phase were higher in patients with AH (184.4 +/- 159.4 pg/ml) and LC+AH (206.9 +/- 174.9 pg/ml) than in healthy subjects (10.4 +/- 5.5 pg/ml, p < 0.001). In particular, in one patient with SAH and one of two nonsurvivors, plasma endotoxin levels were markedly high relative to the other cases. In most survivors, plasma endotoxin levels decreased in the recovery phase, whereas they further increased at the terminal stage in one of two nonsurvivors. Serum interleukin (IL)-6 and IL-8 levels in the acute phase were significantly higher in patients with AH and LC+AH as compared with healthy subjects. These levels were especially high in nonsurvivors and in one patient with SAH. IL-10 increased in two nonsurvivors, one patient with SAH, and one with LC+AH. In the recovery phase, these cytokine levels in survivors tended to decrease, but in nonsurvivors, IL-6 remained high, and IL-8 and IL-10 further increased. Tumor necrosis factor-alpha levels were below the detection limit throughout the course in all patients. Serum lipopolysaccharide binding protein (LBP) generally was elevated in the acute phase and decreased in the recovery phase in all survivors, but in one of the nonsurvivors, LBP was elevated markedly at the terminal stage. In the acute phase, plasma endotoxin levels were correlated positively with white blood cell counts, neutrophil counts, and serum IL-8. IL-8 was correlated positively with neutrophil counts and negatively with serum cholinesterase, hepaplastin test, and serum albumin levels. IL-6 was correlated positively with white blood cell and neutrophil counts, C-reactive protein, and serum total bilirubin and negatively with hepaplastin test and serum total protein levels. Serum LBP was correlated positively with white blood cell and neutrophil counts.
CONCLUSIONS: Endotoxemia and related elevation of IL-8 may play an important role in the activation and migration of neutrophils in patients with alcoholic hepatitis. Marked elevation of inflammatory cytokines, IL-6 and IL-8, are related to severity and poor prognosis of alcoholic hepatitis. Serum LBP may serve as an index of inflammatory reaction in alcoholics.
ESTHER : Fujimoto_2000_Alcohol.Clin.Exp.Res_24_48S
PubMedSearch : Fujimoto_2000_Alcohol.Clin.Exp.Res_24_48S
PubMedID: 10803780

Title : Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy - Tanaka_1999_Am.J.Kidney.Dis_34_289
Author(s) : Tanaka R , Iijima K , Xu H , Inoue Y , Murakami R , Shirakawa T , Nishiyama K , Miwa M , Shiozawa S , Nakamura H , Yoshikawa N
Ref : Am J Kidney Dis , 34 :289 , 1999
Abstract : Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.
ESTHER : Tanaka_1999_Am.J.Kidney.Dis_34_289
PubMedSearch : Tanaka_1999_Am.J.Kidney.Dis_34_289
PubMedID: 10430976
Gene_locus related to this paper: human-PLA2G7