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Yusuke Yoshida

Publications and source records attributed to Yusuke Yoshida.

10 recordsLinked to original sources
PubMed2006

Loss of Catalase-1 (Cat-1) results in decreased conidial viability enhanced by exposure to light in Neurospora crassa.

Light is one of the most important factors inducing morphogenesis in Neurospora crassa. The reception of light triggers the generation of reactive oxygen species (ROS) including hydrogen peroxide (H(2)O(2)). Catalase-1 (Cat-1) is one of three catalases known to detoxify H(2)O(2) into water and oxygen. We reported that the photomorphogenetic characteristics of mutants in nucleoside diphosphate kinase-1 (NDK-1), a light signal transducer, are severely affected, and NDK-1 interacted with Cat-1 in a yeast two-hybrid assay. To disclose the function of Cat-1, we created a Cat-1 loss-of-function mutant (cat-1 ( RIP )) by the repeat induced point-mutation (RIPing) method. No Cat-1 activity was detected in the mutant strain. Forty guanines were replaced with adenines in the cat-1 gene of cat-1 ( RIP ), which caused 30 amino acid substitutions. The mutant strain grew normally, but its conidia and mycelia were more sensitive to H(2)O(2) than those of the wild type. The lack of Cat-1 activity also caused a significant reduction in the conidial germination rate. Furthermore, light enhanced this reduction in cat-1 ( RIP ) more than that in the wild type. Introduction of cat-1 into the mutant reversed all of these defective phenotypes. These results indicate that Cat-1 plays an important role in supporting the survival of conidia under oxidative and light-induced stress.

Amino Acid Substitution↗
PubMed2006

The role of TNF-alpha and its receptors in the production of NGF and GDNF by astrocytes.

The neurotrophic factors, nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF), are produced by astrocytes, and are induced by inflammatory stimuli including bacterial lipopolysaccharide and pro-inflammatory cytokines. In this study, we examined the regulatory mechanisms of tumor necrosis factor-alpha (TNF-alpha)-induced production of neurotrophic factors. We show here that cultured astrocytes express both TNF-alpha receptor 1 (TNFR1) and TNFR2, and that activation of these receptors by TNF-alpha promotes expression of both NGF and GDNF. In addition, we observe that not only exogenous TNF-alpha but also TNF-alpha produced by astrocytes induce NGF and GDNF production in astrocytes. These results suggest that an autocrine loop involving TNF-alpha contributes to the production of neurotrophic factors in response to inflammation.

Animals↗
PubMed2006

Interaction of nucleoside diphosphate kinase and catalases for stress and light responses in Neurospora crassa.

Nucleoside diphosphate kinase (NDK) is an ubiquitous enzyme with the function of a signal transducer. In Neurospora crassa, an ndk-1(P72H) mutant carrying the point mutation Pro72His was isolated. We found that ndk-1(P72H) showed hypersensitivity to oxidative and heat stress and a decrease in the levels of catalase (Cat)-1 and -3 induced by oxidative, heat stress and illumination compared with wild type (Wt). We found, by conducting a yeast two-hybrid assay, that Cat-1 interacted with NDK-1. NDK-1 was suggested to control Cat-1 and Cat-3 at the post-transcriptional level in response to heat, oxidative stress and light.

Catalase↗
PubMed2006

Intraocular pressure change during hemodialysis.

PURPOSE: To evaluate intraocular pressure (IOP) change through hemodialysis and examine other factors to affect IOP change in patients treated with hemodialysis. DESIGN: Prospective, observational case series. METHODS: IOP, blood pressure, and plasma colloid osmotic pressure (COP) were measured in 188 eyes of 95 patients receiving hemodialysis in Nantan General Hospital. RESULTS: IOP significantly decreased after hemodialysis (P = 0.006). Body weight, systolic and diastolic blood pressure also decreased significantly (P < 0.001). COP significantly increased (P < 0.001). Change in IOP correlated negatively with COP change (OD; r = -0.196, OS; r = -0.339) and positively with change in body weight (OD; r = -0.278, OS; r = -0.357). IOP tended to increase after hemodialysis in patients receiving hemodialysis for more than 12 years. CONCLUSIONS: IOP decrease during hemodialysis may be due to COP increase. Patients receiving hemodialysis for a long time are more likely to show IOP increase after hemodialysis.

Adult↗
PubMed2006

Light-dependent subcellular localization of nucleoside diphosphate kinase-1 in Neurospora crassa.

Nucleoside diphosphate kinase (NDK) is a housekeeping enzyme localized in cellular organelles and distributed in various organs in prokaryotes and eukaryotes. In Neurospora crassa, NDK-1 is suggested to control catalases in response to heat, oxidative stress and light. In this study, we identified the presence of NDK-1 during most developmental stages in submerged mycelia, aerial hyphae, asexual conidia and perithecia, and the localization of it in soluble, mitochondrial, nuclear and membrane fractions in the mycelial cell. A light-dependent localization of NDK-1 was shown by Western blotting and immunohistochemical analysis using anti-NDK-1 antibody. In the mycelia, NDK-1 was compartmentalized on the plasma membrane in darkness, while it was relocated in the cytoplasm under light. These results suggest that NDK-1 protein was translocated from the plasma membrane to cytoplasm in response to light, and may interact with catalase.

Blotting, Western↗
PubMed2005

Photomorphogenetic characteristics are severely affected in nucleoside diphosphate kinase-1 (ndk-1)-disrupted mutants in Neurospora crassa.

We previously demonstrated that the NDK-1 (Nucleoside Diphosphate Kinase-1) point mutant, ndk-1(P72H), displays a defective phenotype in light-induced perithecial polarity in Neurospora crassa. To investigate the biological function of NDK-1 in detail, we isolated two ndk-1 mutants, ndk-1(RIP-1) and ndk-1(RIP-2), using the RIPing (repeat induced point mutation) method. Notably, we detected no accumulation of ndk-1(RIP-1) mRNA and truncated NDK-1(RIP-2) protein. The ndk-1(RIP) mutants exhibited altered morphogenesis; (1) aerial hypha was not formed with no conidium formation, (2) the mutants exhibited colonial, and very slow mycelial growth on a solid medium and by shaking culture in a liquid medium, (3) light-induced carotenoid accumulation in mutant mycelia is reduced to less than half that by wild type, (4) the mutants exhibited spiral growth of mycelia, and (5) female sterility with defective protoperithecium formation. The morphogenetic processes of 1, 3, and 5 are light induced in the wild type. Moreover, despite only 10-20% of total nucleoside diphosphate kinase activity, the accumulation of relevant transcripts in the ndk-1(RIP) mutants, such as al-1 and al-2, was similar to that of wild type.

Base Sequence↗
PubMed2005

Oxygen and hydrogen peroxide enhance light-induced carotenoid synthesis in Neurospora crassa.

Previously, we found that intracellular reactive oxygen species (ROS) affect photomorphogenesis in Neurospora crassa. In this study, we investigated the physiological roles of ROS in the response to light and found that the exposure of mycelia to air was important for the light-induced carotenogenesis. Mycelia treated with a high concentration of O(2) gas and H(2)O(2) to release ROS showed an enhancement of light-induced carotenoid accumulation and the expression of gene related to light-inducible carotenogenesis. These results suggested that stimuli caused by the exposure of the mycelia to air containing O(2) gas triggered the light-induced carotenoid synthesis.

Air↗
PubMed2003

Reactive oxygen species affect photomorphogenesis in Neurospora crassa.

In Neurospora crassa, several biological phenomena such as the synthesis of carotenoids in the mycelia and polarity of perithecia are regulated by light. We found that a sod-1 mutant, with a defective Cu,Zn-type superoxide dismutase (SOD), showed accelerated light-dependent induction of carotenoid accumulation in the mycelia compared with the wild type. The initial rate of light-induced carotenoid accumulation in the sod-1 mutant was faster than that in the vvd mutant known to accumulate high concentrations. This acceleration was suppressed by treatment with antioxidant reagents. Light-induced transcription of genes involved in carotenoid synthesis, al-1, -2, and -3, was sustained in the sod-1 mutant, whereas it was transient in the wild type. Moreover sod-1 was defective in terms of light-induced polarity of perithecia. By genetic analysis, the enhancement in light-inducible carotenoid synthesis in sod-1 was dependent on the wild type alleles of wc-1 and wc-2. However, the sod-1;vvd double mutant showed additive effects on the carotenoid accumulation in the mycelia. These results suggested that intracellular reactive oxygen species regulated by SOD-1 could affect the light-signal transduction pathway via WC proteins.

Antioxidants↗
PubMed2003

Putative functions of nucleoside diphosphate kinase in plants and fungi.

The putative functions of NDP (nucleoside diaphosphate) kinases from various organisms focusing to fungi and plants are described. The biochemical reactions catalyzed by NDP kinase are as follows. (i) Phosphotransferring activity from mainly ATP to cognate NDPs generating nucleoside triphosphates (NTPs). (ii) Autophosphorylation activity from ATP and GTP. (iii) Protein kinase (phosphotransferring) activity phosphorylating such as myelin basic protein. NDP kinase could function to provide NTPs as a housekeeping enzyme. However, recent works proved possible functions of the NDP kinases in the processes of signal transduction in various organisms, as described below. 1) By use of the extracts of the mycelia of a filamentous fungus Neurospora crassa blue-light irradiation could increase the phosphorylation of a 15-kDa protein, which was purified and identified to be NDP kinase (NDK-1). By use of the etiolated seedlings of Pisum sativum cv Alaska and Oryza sativa red-light irradiation of intact plants increased the phosphorylation of NDP kinase. However, successive irradiation by red-far-red reversed the reaction, indicating that phytochrome-mediated light signals are transduced to the phosphorylation of NDP kinase. 2) NDP kinase localizing in mitochondria is encoded by nuclear genome and different from those localized in cytoplasm. NDP kinase in mitochondria formed a complex with succinyl CoA synthetase. 3) In Spinicia oleraceae two different NDP kinases were detected in the chloroplast, and in Pisum sativum two forms of NDP kinase originated from single species of mRNA could be detected in the choloroplast. However, the function of NDP kinases in the choloroplast is not yet known. 4) In Neurospora crassa a Pro72His mutation in NDP kinase (ndk-1Pro72His) deficient in the autophosphorylation and protein kinase activity resulted in lacking the light-induced polarity of perithecia. In wild-type directional light irradiation parallel to the solid medium resulted in the formation of the perithecial beak at the top of perithecia, which was designated as "light-induced polarity of perithecia." In wild-type in darkness the beak was formed at random places on perithecia, and in ndkPro72His mutant the perithecial beak was formed at random places even under directional light illumination. The introduction of genomic DNA and cDNA for ndk-1 demonstrated that the wild-type DNAs suppressed the mutant phenotype. With all these results except for the demonstration in Neurospora, most of the phenomena are elusive and should be solved in the molecular levels concerning with NDP kinases.

Amino Acid Sequence↗