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Le Mao-hua - One of the best experts on this subject based on the ideXlab platform.

Takafumi Kasumi - One of the best experts on this subject based on the ideXlab platform.

  • Complementary Function of two transketolase isoforms from Moniliella megachiliensis in relation to stress response
    AMB Express, 2017
    Co-Authors: Hisashi Iwata, Yosuke Kobayashi, Daiki Mizushima, Taisuke Watanabe, Jun Ogihara, Takafumi Kasumi
    Abstract:

    Two transketolase isogenes, MmTKL1 and MmTKL2, isolated from Moniliella megachiliensis were investigated for their roles in stress response and erythritol biosynthesis. The encoded proteins were highly homologous in amino acid sequence and domain structure. Two stress response elements (STREs) were found upstream of MmTKL1, while no STRE was found upstream of MmTKL2. In contrast, two Ap-1 elements were present upstream of MmTKL2, but none were detected upstream of MmTKL1. MmTKL2 partially complemented the aromatic amino acid auxotrophy of a Saccharomyces cerevisiae tkl1 deletion mutant, suggesting that at least one of the MmTKLs Functioned as a transketolase in vivo. In response to short-term osmotic stress (20% glucose or 1.2 M NaCl) in Moniliella cells, MmTKL1 expression increased rapidly through the first 40 min before subsequently decreasing gradually, while MmTKL2 expression showed no significant change. In contrast, short-term oxidative stress (0.15 mM menadione) induced considerable increases in MmTKL2, while MmTKL1 expression remained low under the same conditions. Long-term osmotic stress (20% glucose) yielded increased expression of both genes starting at 12 h and continuing through 72 h. During either osmotic or oxidative stress, intracellular erythritol accumulation could clearly be correlated with the pattern of expression of either MmTKL1 or MmTKL2. These results strongly suggested that MmTKL1 is responsible primarily for the response to osmotic stress, while MmTKL2 is responsible primarily for the response to oxidative stress. Thus, we postulate that the two transketolase isoforms of M. megachiliensis play distinct and Complementary roles in coordinating erythritol production in response to distinct environmental stresses.

  • Complementary Function of mitogen activated protein kinase hog1 from trichosporonoides megachiliensis in saccharomyces cerevisiae under hyper osmotic stress
    Journal of Bioscience and Bioengineering, 2013
    Co-Authors: Junjiro Yoshida, Yosuke Kobayashi, Jun Ogihara, Yosuke Tanaka, Yoshiyuki Koyama, Jun Kato, Jun Shima, Takafumi Kasumi
    Abstract:

    A (TmHog1) gene encoding a mitogen-activated protein kinase (MAPK) homologous to Saccharomyces cerevisiae Hog1 (ScHog1) involved in hyper-osmotic stress signaling was isolated from Trichosporonoides megachiliensis SN-124A, an erythritol-producing yeast. Although TmHog1, like other Hog1 homologs, encoded a kinase catalytic domain containing TGY motif, it was 50–60 amino acid residues shorter than the ScHog1. A TmHog1 transgene rescued the osmotic sensitivity and glycerol production defect of S. cerevisiae hog1Δ, a highly osmo-sensitive strain that does not produce glycerol, a compatible solute, during osmotic stress. Functional analyses of chimeric Hog1 proteins constructed from ScHog1 and TmHog1 sequences indicated that the C-terminal region of TmHog1 is more effective for glycerol biosynthesis than ScHog1 under osmotic stress.

E Schwindt - One of the best experts on this subject based on the ideXlab platform.

  • some existence results on periodic solutions of euler lagrange equations in an orlicz sobolev space setting
    Nonlinear Analysis-theory Methods & Applications, 2015
    Co-Authors: Sonia Acinas, L Buri, G Giubergia, Fernando Mazzone, E Schwindt
    Abstract:

    Abstract In this paper we consider the problem of finding periodic solutions of certain Euler–Lagrange equations. We employ the direct method of the calculus of variations, i.e. we obtain solutions minimizing certain Functional I . We give conditions which ensure that I is finitely defined and differentiable on certain subsets of Orlicz–Sobolev spaces W 1 L Φ associated to an N -Function Φ . We show that, in some sense, it is necessary for the coercivity that the Complementary Function of Φ satisfy the Δ 2 -condition. We conclude by discussing conditions for the existence of minima of I .

  • Some existence results on periodic solutions of Euler–Lagrange equations in an Orlicz–Sobolev space setting
    Nonlinear Analysis: Theory Methods and Applications, 2015
    Co-Authors: Sonia Acinas, L Buri, G Giubergia, Fernando Mazzone, E Schwindt
    Abstract:

    In this paper we consider the problem of finding periodic solutions of certain Euler-Lagrange equations. We employ the direct method of the calculus of variations, i.e. we obtain solutions minimizing certain Functional I. We give conditions which ensure that I is finitely defined and differentiable on certain subsets of Orlicz-Sobolev spaces W 1 L Φ associated to an N-Function Φ. We show that, in some sense, it is necessary for the coercitivity that the Complementary Function of Φ satisfy the ∆ 2-condition. We conclude by discussing conditions for the existence of minima of I.

Nicolas Pallet - One of the best experts on this subject based on the ideXlab platform.

  • the unfolded protein response regulates an angiogenic response by the kidney epithelium during ischemic stress
    Journal of Biological Chemistry, 2012
    Co-Authors: Nicolas Bouvier, Sophie Fougeray, Philippe Beaune, Eric Thervet, Nicolas Pallet
    Abstract:

    Abstract Ischemic injuries permanently affect kidney tissue and challenge cell viability, promoting inflammation and fibrogenesis. Ischemia results in nutrient deprivation, which triggers endoplasmic reticulum stress, ultimately resulting in the unfolded protein response (UPR). The aim of this study was to test whether the UPR could promote an angiogenic response independently of the HIF-1α pathway during ischemic stress in the human kidney epithelium. Glucose deprivation induced the secretion of vascular endothelial growth factor A (VEGFA), basic fibroblast growth factor (bFGF) and angiogenin (ANG) in human kidney epithelial cells independently of HIF-1α. Glucose deprivation, but not hypoxia, triggered endoplasmic reticulum stress and activated the UPR. RNA interference-mediated inhibition of the gene encoding the kinase PERK decreased VEGFA and bFGF expression, but neither gene was affected by the inhibition of IRE1α or ATF6. Furthermore, we show that the expression of angiogenin, which inhibits protein synthesis, is regulated by both IRE1α and PERK, which could constitute a Complementary Function of the UPR in the repression of translation. In a rat model of acute ischemic stress, we show that the UPR is activated in parallel with VEGFA, bFGF, and ANG expression and independently of HIF-1α.

Jongshik Chung - One of the best experts on this subject based on the ideXlab platform.

  • simultaneous removal of cod and ammonium from landfill leachate using an anaerobic aerobic moving bed biofilm reactor system
    Waste Management, 2008
    Co-Authors: Sheng Chen, Jongshik Chung
    Abstract:

    Abstract The performance of a moving-bed biofilm reactor (MBBR) system with an anaerobic–aerobic arrangement was investigated to treat landfill leachate for simultaneous removal of COD and ammonium. It was found that the anaerobic MBBR played a major role in COD removal due to methanogenesis, and the aerobic MBBR acted as COD-polishing and ammonium removal step. The contribution of the anaerobic MBBR to total COD removal efficiency reached 91% at an organic loading rate (OLR) of 4.08 kgCOD/(m 3  d), and gradually decreased to 86% when feed OLR was increased to 15.70 kgCOD/(m 3  d). Because of the Complementary Function of the aerobic reactor, the total COD removal efficiency of the system had a slight decrease from 94% to 92% even though the feed OLR was increased from 4.08 to 15.70 kgCOD/(m 3  d). Hydraulic retention time (HRT) had a significant effect on NH 4 + -N removal; more than 97% of the total NH 4 + -N removal efficiency could be achieved when the HRT of the aerobic MBBR was more than 1.25 days. The anaerobic–aerobic system had a strong tolerance to shock loading. A decrease in COD removal efficiency of only 7% was observed when the OLR was increased by four times and shock duration was 24 h, and the system could recover the original removal efficiency in 3 days. The average sludge yield of the anaerobic reactor was estimated to be 0.0538 gVSS/gCOD rem .