The Inheritance of Histone Modifications Depends upon the Location in the Chromosome in Saccharomyces cerevisiae

Histone modifications are important epigenetic features of chromatin that must be replicated faithfully. However, the molecular mechanisms required to duplicate and maintain histone modification patterns in chromatin remain to be determined. Here, we show that the introduction of histone modifications into newly deposited nucleosomes depends upon their location in the chromosome. In Saccharomyces cerevisiae, newly deposited nucleosomes consisting of newly synthesized histone H3-H4 tetramers are distributed throughout the entire chromosome. Methylation of lysine 4 on histone H3 (H3-K4), a hallmark of euchromatin, is introduced into these newly deposited nucleosomes, regardless of whether the neighboring preexisting nucleosomes harbor the K4 mutation in histone H3. Furthermore, if the heterochromatin-binding protein Sir3 is unavailable during DNA replication, histone H3-K4 methylation is introduced onto newly deposited nucleosomes in telomeric heterochromatin. Thus, a conservative distribution model most accurately explains the inheritance of histone modifications because the location of histones within euchromatin or heterochromatin determines which histone modifications are introduced

Radiocesium and potassium decreases in wild edible plants by food processing

More than 4 years has been past since March 11, 2011, and, at this stage, foods exceeding the standard limits of radiocesium were mainly from the wild. Thus one of the public’s main concerns is how to decrease ingestion of radiocesium from foods they have collected from the wild as well as from their home-grown fruits because these food materials are not monitored. In this study, we focused on wild edible plants and fruits and the effects of washing, boiling and pealing to remove radiocesium were observed. Samples were collected in 2013 and 2014 from Chiba and Fukushima Prefectures, e.g., young bamboo shoots, giant butterbur, chestnuts, etc. For wild edible plants were separated into three portions to make raw, washed and boiled samples. For fruit samples (i.e. persimmon, loquat and Japanese plum) fruit parts were separated into skin, flesh and seeds. It was found that washing plants is not effective to remove both 137Cs and 40K, and boiling provided different removal effects by plant tissues. There was a tendency that the retention factors of 137Cs and 40K for thinner plant body sample (leaves) were higher than those of thicker plant body types, e.g. giant butterbur petiole and bamboo shoots. Thus the boiling time as well as the crop thickness should affect radiocesium retention in processed foods. For fruits, 137Cs concentration was higher in skin than in fruit flesh for persimmon and loquat, however, Japanese apricot showed different distribution

The combination of NAD+-dependent deacetylase gene deletion and the interruption of gluconeogenesis causes increased glucose metabolism in budding yeast

Metabolic engineering focuses on rewriting the metabolism of cells to enhance native products or endow cells with the ability to produce new products. This engineering has the potential for wide-range application, including the production of fuels, chemicals, foods and pharmaceuticals. Glycolysis manages the levels of various secondary metabolites by controlling the supply of glycolytic metabolites. Metabolic reprogramming of glycolysis is expected to cause an increase in the secondary metabolites of interest. In this study, we constructed a budding yeast strain harboring the combination of triple sirtuin gene deletion (hst3Δ hst4Δ sir2Δ) and interruption of gluconeogenesis by the deletion of the FBP1 gene encoding fructose-1,6-bisphosphatase (fbp1Δ). hst3Δ hst4Δ sir2Δ fbp1Δ cells harbored active glycolysis with high glucose consumption and active ethanol productivity. Using capillary electrophoresis±time-of-flight mass spectrometry (CE-TOF/MS) analysis, hst3Δ hst4Δ sir2Δ fbp1Δ cells accumulated not only glycolytic metabolites but also secondary metabolites, including nucleotides that were synthesized throughout the pentose phosphate (PP) pathway, although various amino acids remained at low levels. Using the stable isotope labeling assay for metabolites, we confirmed that hst3Δ hst4Δ sir2Δ fbp1Δ cells directed the metabolic fluxes of glycolytic metabolites into the PP pathway. Thus, the deletion of three sirtuin genes (HST3, HST4 and SIR2) and the FBP1 gene can allow metabolic reprogramming to increase glycolytic metabolites and several secondary metabolites except for several amino acids