32 research outputs found

    Speech-like Emotional Sound Generator by WaveNet

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    In this paper, we propose a new algorithm to generate Speech-like Emotional Sound (SES). Emotional information plays an important role in human communication, and speech is one of the most useful media to express emotions. Although, in general, speech conveys emotional information as well as linguistic information, we have undertaken the challenge to generate sounds that convey emotional information without linguistic information, which results in making conversations in human-machine interactions more natural in some situations by providing non-verbal emotional vocalizations. We call the generated sounds “speech-like”, because the sounds do not contain any linguistic information. For the purpose, we propose to employ WaveNet as a sound generator conditioned by only emotional IDs. The idea is quite different from WaveNet Vocoder that synthesizes speech using spectrum information as auxiliary features. The biggest advantage of the idea is to reduce the amount of emotional speech data for the training. The proposed algorithm consists of two steps. In the first step, WaveNet is trained to obtain phonetic features using a large speech database, and in the second step, WaveNet is re-trained using a small amount of emotional speech. Subjective listening evaluations showed that the SES could convey emotional information and was judged to sound like a human voice

    Characterization of Bifidobacterium kashiwanohense that utilizes both milk- and plant-derived oligosaccharides

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    ABSTRACTBifidobacteria are prominent members of the human gut microbiota throughout life. The ability to utilize milk- and plant-derived carbohydrates is important for bifidobacterial colonization of the infant and adult gut. The Bifidobacterium catenulatum subspecies kashiwanohense (B. kashiwanohense) was originally isolated from infant feces. However, only a few strains have been described, and the characteristics of this subspecies have been poorly investigated. Here, we characterized genotypes and phenotypes of 23 B. kashiwanohense-associated strains, including 12 newly sequenced isolates. Genome-based analysis clarified the phylogenetic relationship between these strains, revealing that only 13 strains are genuine B. kashiwanohense. We defined specific marker sequences and investigated the worldwide prevalence of B. kashiwanohense based on metagenome data. This revealed that not only infants but also adults and weaning children harbor this subspecies in the gut. Most B. kashiwanohense strains utilize long-chain xylans and possess genes for extracellular xylanase (GH10), arabinofuranosidase and xylosidase (GH43), and ABC transporters that contribute to the utilization of xylan-derived oligosaccharides. We also confirmed that B. kashiwanohense strains utilize short- and long-chain human milk oligosaccharides and possess genes for fucosidase (GH95 and GH29) and specific ABC transporter substrate-binding proteins that contribute to the utilization of a wide range of human milk oligosaccharides. Collectively, we found that B. kashiwanohense strains utilize both plant- and milk-derived carbohydrates and identified key genetic factors that allow them to assimilate various carbohydrates

    Protective effect of 3-hydroxybutyrate against endoplasmic reticulum stress-associated vascular endothelial cell damage induced by low glucose exposure.

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    The aim of this study was to elucidate the mechanism by which severe hypoglycemia accelerates vascular complications. Furthermore, we assessed the possible protective effect of ketone bodies against the endothelial cell damage caused by glucose deficiency.Human umbilical vein endothelial cells (HUVECs) were cultured at a glucose level of either 0.56 or 5.6 mmol/L with or without 3-hydroxybutyrate (3-HB) supplementation. Cell viability was assessed with a CCK-8 assay and a lactate dehydrogenase (LDH) release assay. The activity of caspases was measured using fluorogenic substrates. The expression of genes associated with endothelial cell function and endoplasmic reticulum (ER) stress was evaluated by real-time quantitative PCR. Protein levels of ER stress-related molecules were assessed by Western blotting.Culture of HUVECs in low-glucose medium for 24 or 48 h resulted in reduction of cell viability accompanied by activation of caspase-3/7 and caspase-8. The addition of a pan caspase inhibitor attenuated the cell death. After incubation in the low-glucose medium, we found reduced mRNA and protein levels of endothelial nitric oxide synthase. ER stress responses mediated by phosphorylation of protein kinase RNA-like ER kinase (PERK) and cleavage of activating transcription factor 6 (ATF6) were augmented, but X-box binding protein 1 (Xbp1) splicing was reduced. Most of these responses to glucose deficiency were significantly attenuated by supplementation with 3-HB.These observations showed that exposure to low glucose induces ER stress, caspase activation, endothelial cell dysfunction and cell death. The beneficial effects of 3-HB shown in this study suggest that hypoketonemic severe hypoglycemia induced by insulin injections or insulin secretagogue administration may be more harmful than hyperketonemic severe hypoglycemia

    Beneficial effects of metformin on energy metabolism and visceral fat volume through a possible mechanism of fatty acid oxidation in human subjects and rats - Fig 6

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    <p><b>The protein expressions of pAMPK and pACC in the liver of SD rats at 15 weeks old.inhibo</b> A; Western blot analysis, B; Densitometric quantification. Open bars denote control group and black bars denote metformin-treated group. Data are presented as mean ± S.E. (n = 3 in each group). *P<0.05 vs. control groups.</p

    Refined Regio- and Stereoselective Hydroxylation of l‑Pipecolic Acid by Protein Engineering of l‑Proline <i>cis</i>-4-Hydroxylase Based on the X‑ray Crystal Structure

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    Enzymatic regio- and stereoselective hydroxylation are valuable for the production of hydroxylated chiral ingredients. Proline hydroxylases are representative members of the nonheme Fe<sup>2+</sup>/α-ketoglutarate-dependent dioxygenase family. These enzymes catalyze the conversion of l-proline into hydroxy-l-prolines (Hyps). l-Proline <i>cis</i>-4-hydroxylases (<i>cis</i>-P4Hs) from <i>Sinorhizobium meliloti</i> and <i>Mesorhizobium loti</i> catalyze the hydroxylation of l-proline, generating <i>cis</i>-4-hydroxy-l-proline, as well as the hydroxylation of l-pipecolic acid (l-Pip), generating two regioisomers, <i>cis</i>-5-Hypip and <i>cis</i>-3-Hypip. To selectively produce <i>cis</i>-5-Hypip without simultaneous production of two isomers, protein engineering of <i>cis</i>-P4Hs is required. We therefore carried out protein engineering of <i>cis</i>-P4H to facilitate the conversion of the majority of l-Pip into the <i>cis</i>-5-Hypip isomer. We first solved the X-ray crystal structure of <i>cis</i>-P4H in complex with each of l-Pro and l-Pip. Then, we conducted three rounds of directed evolution and successfully created a <i>cis</i>-P4H triple mutant, V97F/V95W/E114G, demonstrating the desired regioselectivity toward <i>cis</i>-5-Hypip
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