Mechanisms and consequences of phagocytosis on influenza virus-infected cells

金沢大学医薬保健研究域薬学系Influenza virus-infected cells are induced to undergo apoptosis and become susceptible to phagocytosis. Data from our in vitro and in vivo experiments have suggested that 1) alveolar macrophages and neutrophils phagocytose influenza virus-infected cells in an apoptosis-dependent manner; 2) the membrane phospholipid phosphatidylserine and viral neuraminidase-processed carbohydrates at the surface of target cells and phagocytes, respectively, are involved in the association of the two types of cells; and 3) phagocytic elimination of virus-infected cells leads to a reduction in the pathogenesis of influenza. These findings could lead to the development of a novel antiviral agent against influenza. © 2008 Bentham Science Publishers Ltd.全文公開20090

Identification of amino acid residues of mammalian mitochondrial phosphate carrier important for its functional expression in yeast cells, as achieved by PCR-mediated random mutation and gap-repair cloning

The mitochondrial phosphate carrier (PiC) of mammals, but not the yeast one, is synthesized with a presequence. The deletion of this presequence of the mammalian PiC was reported to facilitate the import of the carrier into yeast mitochondria, but the question as to whether or not mammalian PiC could be functionally expressed in yeast mitochondria was not addressed. In the present study, we first examined whether the defective growth on a glycerol plate of yeast cells lacking the yeast PiC gene could be reversed by the introduction of expression vectors of rat PiCs. The introduction of expression vectors encoding full-length rat PiC (rPiC) or rPiC lacking the presequence (ΔNrPiC) was ineffective in restoring growth on the glycerol plates. When we examined the expression levels of individual rPiCs in yeast mitochondria, ΔNrPiC was expressed at a level similar to that of yeast PiC, but that of rPiC was very low. These results indicated that ΔNrPiC expressed in yeast mitochondria is inert. Next, we sought to isolate “revertants” viable on the glycerol plate by expressing randomly mutated ΔNrPiC, and obtained two clones. These clones carried either of two mutations, F267S or F282S; and these mutations restored the transport function of ΔNrPiC in yeast mitochondria. These two Phe residues were conserved in human carrier (hPiC), and the transport function of ΔNhPiC expressed in yeast mitochondria was also markedly improved by their substitutions. Thus, substitution of F267S or F282S was concluded to be important for functional expression of mammalian PiCs in yeast mitochondria

Embedding a Differentiable Mel-cepstral Synthesis Filter to a Neural Speech Synthesis System

This paper integrates a classic mel-cepstral synthesis filter into a modern neural speech synthesis system towards end-to-end controllable speech synthesis. Since the mel-cepstral synthesis filter is explicitly embedded in neural waveform models in the proposed system, both voice characteristics and the pitch of synthesized speech are highly controlled via a frequency warping parameter and fundamental frequency, respectively. We implement the mel-cepstral synthesis filter as a differentiable and GPU-friendly module to enable the acoustic and waveform models in the proposed system to be simultaneously optimized in an end-to-end manner. Experiments show that the proposed system improves speech quality from a baseline system maintaining controllability. The core PyTorch modules used in the experiments will be publicly available on GitHub.Comment: Submitted to ICASSP 202

Articulatory Text-to-Speech Synthesis Using the Digital Waveguide Mesh Driven by a Deep Neural Network

Following recent advances in direct modeling of the speech waveform using a deep neural network, we propose a novel method that directly estimates a physical model of the vocal tract from the speech waveform, rather than magnetic resonance imaging data. This provides a clear relationship between the model and the size and shape of the vocal tract, offering considerable flexibility in terms of speech characteristics such as age and gender. Initial tests indicate that despite a highly simplified physical model, intelligible synthesized speech is obtained. This illustrates the potential of the combined technique for the control of physical models in general, and hence the generation of more natural-sounding synthetic speech

Comparison of 2 expression systems using COS7 cells and yeast cells for expression of heart/muscle-type carnitine palmitoyltransferase 1 (CPT1b)

Carnitine palmitoyltransferase 1 (CPT1), catalyzing the transfer of the acyl group from acyl-CoA to carnitine to form acylcarnitine, is located at the outer mitochondrial membrane. Because it is easily inactivated by solubilization, expression systems using living cells are essential for its functional characterization. COS7 cells or yeast cells are often utilized for this purpose; however, the advantages/disadvantages of the use of these cells or the question as to how the CPT1 enzyme expressed by these cells differs are still uncertain. In this study, we characterized the heart/muscle-type isozyme of rat CPT1 (CPT1b) expressed by these 2 cellular expression systems. The mitochondrial fraction prepared from yeast cells expressing CPT1b showed 25% higher CPT1 activity than that obtained from COS7 cells. However, the expression level of CPT1b in the former was 3.8 times lower than that in the latter; and thus, under the present experimental conditions, the specific activity of CPT1b expressed in yeast cells was estimated to be approximately 5 times higher than that expressed in COS7 cells. Possible reasons for this difference are discussed

A study on the Dressing of Diamond Wheels by Lapping Method

In this study clusters of resin bonded and metal bonded diamond wheels were dressed by lapping with GC abrasive grains. GC grain sizes at varying pressures were investigated to determine the effects of these various dressing processes. The main results obtained are: (1) Effects of the GC grain sizes and pressures on the protrusion height of the diamonds, the ratio of the fractured diamond grains, and the rate of the fractured areas are cleared quantitatively. (2) The method of lapping is effective not only for roughing the diamond grains to protrude from the bended surface but it is also effective in sharpening the worn and flat diamond grains under suitable conditions