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L. R. Fayura D. V. Fedorovych T. M. Prokopiv Yu. R. Boretsky A. A. Sibirny 《Microbiology》2007,76(1):55-59
The yeast Pichia guilliermondii is capable of riboflavin overproduction under iron deficiency. The rib80, hit1, and red6 mutants of this species, which exhibit impaired riboflavin regulation, are also distinguished by increased iron concentrations in the cells and mitochondria, morphological changes in the mitochondria, as well as decreased growth rates (except for red6) and respiratory activity. With sufficient iron supply, the rib80 and red6 mutations cause a 1.5–1.8-fold decrease in the activity of such Fe-S cluster proteins as aconitase and flavocytochrome b 2, whereas the hit1 mutation causes a six-fold decrease. Under iron deficiency, the activity of these enzymes was equally low in all of the studied strains. 相似文献
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Yuriy V. Pynyaha Yuriy R. Boretsky Daria V. Fedorovych Lubov R. Fayura Andriy I. Levkiv Vira M. Ubiyvovk Olha V. Protchenko Caroline C. Philpott Andriy A. Sibirny 《Biometals》2009,22(6):1051-1061
Pichia guilliermondii is a representative of yeast species that overproduce riboflavin (vitamin B2) in response to iron deprivation. P. guilliermondii
YFH1 gene coding for frataxin homologue, eukaryotic mitochondrial protein involved in iron trafficking and storage, was identified
and deleted. Constructed P. guilliermondii Δyfh1 mutant grew very poorly in a sucrose-containing synthetic medium supplemented with sulfate or sulfite as a sole sulfur source.
Addition of sodium sulfide, glutathione, cysteine, methionine, N-acetyl-l-cysteine partially restored growth rate of the mutant suggesting that it is impaired in sulfate assimilation. Cellular iron
content in Δyfh1 mutant was ~3–3.5 times higher as compared to the parental strain. It produced 50–70 times more riboflavin in iron sufficient
synthetic media relative to the parental wild-type strain. Biomass yield of the mutant in the synthetic glutathione containing
medium supplemented with glycerol as a sole carbon source was 1.4- and 2.6-fold increased as compared to sucrose and succinate
containing media, respectively. Oxygen uptake of the Δyfh1 mutant on sucrose, glycerol or succinate, when compared to the parental strain, was decreased 5.5-, 1.7- and 1.5-fold, respectively.
Substitution of sucrose or glycerol in the synthetic iron sufficient medium with succinate completely abolished riboflavin
overproduction by the mutants. Deletion of the YFH1 gene caused hypersensitivity to hydrogen peroxide and exogenously added riboflavin and led to alterations in superoxide dismutase
activities. Thus, deletion of the gene coding for yeast frataxin homologue has pleiotropic effect on metabolism in P. guilliermondii. 相似文献
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Tetyana M. Prokopiv Dariya V. Fedorovych Yuriy R. Boretsky Andriy A. Sibirny 《Current microbiology》2013,66(1):79-87
Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. Under iron deprivation conditions, Pichia guilliermondii cells increase production of riboflavin and malondialdehyde and the formation of protein carbonyl groups, which reflect increased intracellular content of reactive oxygen species. In this study, we found that P. guilliermondii iron deprived cells showed dramatically decreased catalase and superoxide dismutase activities. Previously reported mutations rib80, rib81, and hit1, which affect repression of riboflavin synthesis and iron accumulation by iron ions, caused similar drops in activities of the mentioned enzymes. These findings could explain the previously described development of oxidative stress in iron deprived or mutated P. guilliermondii cells that overproduce riboflavin. Similar decrease in superoxide dismutase activities was observed in iron deprived cells in the non-flavinogenic yeast Saccharomyces cerevisiae. 相似文献
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Roman M Stilling Hendrik Urbanke Vincenzo Capece Susanne Burkhardt Sanaz Bahari‐Javan Jonas Barth Farahnaz Sananbenesi Anna L Schütz Jerzy Dyczkowski Ana Martinez‐Hernandez Cemil Kerimoglu Sharon YR Dent Stefan Bonn Klaus G Reymann Andre Fischer 《The EMBO journal》2014,33(17):1912-1927
Neuronal histone acetylation has been linked to memory consolidation, and targeting histone acetylation has emerged as a promising therapeutic strategy for neuropsychiatric diseases. However, the role of histone‐modifying enzymes in the adult brain is still far from being understood. Here we use RNA sequencing to screen the levels of all known histone acetyltransferases (HATs) in the hippocampal CA1 region and find that K‐acetyltransferase 2a (Kat2a)—a HAT that has not been studied for its role in memory function so far—shows highest expression. Mice that lack Kat2a show impaired hippocampal synaptic plasticity and long‐term memory consolidation. We furthermore show that Kat2a regulates a highly interconnected hippocampal gene expression network linked to neuroactive receptor signaling via a mechanism that involves nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB). In conclusion, our data establish Kat2a as a novel and essential regulator of hippocampal memory consolidation. 相似文献
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The Hedgehog (Hh) signaling pathway differentially utilizes the primary cilium in mammals and fruit flies. Recent work, including
a study in BMC Biology, demonstrates that Hh signals through the cilium in zebrafish, clarifying the evolution of Hh signal transduction. 相似文献
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Boretsky YR Pynyaha YV Boretsky VY Fedorovych DV Fayura LR Protchenko O Philpott CC Sibirny AA 《FEMS yeast research》2011,11(3):307-314
Pichia guilliermondii is a representative of a group of so-called flavinogenic yeast species that overproduce riboflavin (vitamin B(2)) in response to iron limitation. Using insertion mutagenesis, we isolated P. guilliermondii mutants overproducing riboflavin. Analysis of nucleotide sequence of recombination sites revealed that insertion cassettes integrated into the genome disrupting P. guilliermondii genes similar to the VMA1 gene of Ashbya gossypii and Saccharomyces cerevisiae and FES1 and FRA1 genes of S. cerevisiae. The constructed P. guilliermondiiΔvma1-17 mutant possessed five- to sevenfold elevated riboflavin production and twofold decreased iron cell content as compared with the parental strain. Pichia guilliermondiiΔfra1-45 mutant accumulated 1.8-2.2-fold more iron in the cells and produced five- to sevenfold more riboflavin as compared with the parental strain. Both Δvma1-17 and Δfes1-77 knockout strains could not grow at 37 °C in contrast to the wild-type strain and the Δfra1-45 mutant. Increased riboflavin production by the wild-type strain was observed at 37 °C. Although the Δfes1-77 mutant did not overproduce riboflavin, it showed partial complementation when crossed with previously isolated P. guilliermondii riboflavin-overproducing mutant rib80-22. Complementation analysis revealed that Δvma1-17 and Δfra1-45 mutants are distinct from previously reported riboflavin-producing mutants hit1-1, rib80-22 and rib81-31 of this yeast. 相似文献
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