REGULATION OF GLYCOSYLATION IN MAMMALIAN CELL LINES: INSIGHTS FROM STRUCTURAL GLYCOMICS, ANALYSIS OF GLYCOSYLATION-RELATED GENES AND FUNCTIONAL RNAI SCREENS

Ph.DDOCTOR OF PHILOSOPH

Controlling Capillary-Driven Fluid Transport in Paper-Based Microfluidic Devices Using a Movable Valve

This paper describes a novel, strategy for fabricating the movable valve on paper-based microfluidic devices to manipulate capillary-driven fluids. The movable valve fabrication is first realized using hollow rivets as the-holding center it, control the paper channel in different layer movement that Jesuits in the :channel's connection or disconnection. The relatively simple Valve fabrication procedure is robust, Versatile, and, compatible with microfluidic paper-based analytical devices (mu PADs) with differing levels of complexity. It is remarkable that the movable valve can be convenient and free to control fluid without the timing setting; advantages that make it user-friendly for untrained users to carry out the complex multistep operations. For the, performance of the Movable valve to be-verified, several different designs of mu PADs were tested and obtained with satisfactory results. In addition; in the proof-of-concept enzyme-linked immunosorbent assay experiments, we demonstrate the use of these valves in mu PADs for the successful analysis of samples of carcino-embryonic antigen, showing good sensitivity and reproducibility. We hope this technique will open new avenues for the fabrication of paper-based valves in an easily adoptable and widely available way on mu PADs and provide potential point-of-Care applications in the future.This paper describes a novel, strategy for fabricating the movable valve on paper-based microfluidic devices to manipulate capillary-driven fluids. The movable valve fabrication is first realized using hollow rivets as the-holding center it, control the paper channel in different layer movement that Jesuits in the :channel's connection or disconnection. The relatively simple Valve fabrication procedure is robust, Versatile, and, compatible with microfluidic paper-based analytical devices (mu PADs) with differing levels of complexity. It is remarkable that the movable valve can be convenient and free to control fluid without the timing setting; advantages that make it user-friendly for untrained users to carry out the complex multistep operations. For the, performance of the Movable valve to be-verified, several different designs of mu PADs were tested and obtained with satisfactory results. In addition; in the proof-of-concept enzyme-linked immunosorbent assay experiments, we demonstrate the use of these valves in mu PADs for the successful analysis of samples of carcino-embryonic antigen, showing good sensitivity and reproducibility. We hope this technique will open new avenues for the fabrication of paper-based valves in an easily adoptable and widely available way on mu PADs and provide potential point-of-Care applications in the future

Anomalous Photovoltaic Effect in Centrosymmetric Ferroelastic BiVO4

The anomolous photovoltaic (APV) effect is an intriguing phenomenon and rarely observed in bulk materials that structurally have an inversion symmetry. Here, the discovery of such an APV effect in a centrosymmetric vanadate, BiVO4, where noticeable above‐bandgap photovoltage and a steady‐state photocurrent are observed in both ceramics and single crystals even when illuminated under visible light, is reported. Moreover, the photovoltaic voltage can be reversed by the stress modulation, and a sine‐function relationship between the photovoltage and stress directional angle is derived. Microstructure and strain‐field analysis reveal localized asymmetries that are caused by strain fluctuations in bulk centrosymmetric BiVO4. On the basis of the experimental results, a flexoelectric coupling via a strain‐induced local polarization mechanism is suggested to account for the APV effect observed. This work not only allows new applications for BiVO4 in optoelectronic devices but also deepens insights into the mechanisms underlying the APV effect.This work was financially supported by the National Key R&D Program of China (2016YFA0201103), the Natural Science Foundation of China (Grant Nos. 21577143, 51502289, 51872311, and 51502325), the Natural Science Foundation of Fujian Province (Grant Nos. 2017J05031 and 2018I0021), the Frontier Science Key Project of the Chinese Academy of Sciences (QYZDB-SSW-JSC027), and the Instrument Developing Project of Chinese Academy of Sciences (Grant No. ZDKYYQ20180004). Y.L. thanks the Australian Research Council for support in the form of an ARC discovery program grant

Novel Ge–Ga–Te–CsBr Glass System with Ultrahigh Resolvability of Halide

International audienceCO2 molecule, one of the main molecules to create new life, should be probed accurately to detect the existence of life in exoplanets. The primary signature of CO2 molecule is approximately 15 μm, and traditional S- and Se-based glass fibers are unsuitable. Thus, Te-based glass is the only ideal candidate glass for far-infrared detection. In this study, a new kind of Te-based chalcohalide glass system was discovered with relatively stable and large optical band gap. A traditional melt-quenching method was adopted to prepare a series of (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glass samples. Experiment results indicate that the glass-forming ability and thermal properties of glass samples were improved when CsBr was added in the host of Ge–Ga–Te glass. Ge–Ga–Te glass could remarkably dissolve CsBr content as much as 85 at.%, which is the highest halide content in all reports for Te-based chalcohalide glasses. Moreover, ΔT values of these glass samples were all above 100 °C. The glass sample (Ge15Ga10Te75)65 (CsBr)35 with ΔT of 119 °C was the largest, which was 7 °C larger than that of Ge15Ga10Te75 host glass. The infrared transmission spectra of these glasses show that the far-infrared cut-off wavelengths of (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glasses were all beyond 25 μm. In conclusion, (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glasses are potential materials for far-infrared optical applicatio

Novel NaI improved Ge–Ga–Te far-infrared chalcogenide glasses

International audienceIn this study, a novel Te-based glass system was investigated. Some properties of Ge–Ga–Te–NaI chalcogenide glasses such as physical, thermal and optical transmitting were discussed. XRD patterns show this glass system with best amorphous state can dissolve content of NaI as much as 35 at.%. The lowest cut-off wavelength of glass samples is 1645 nm which is the smallest wavelength among the reported Te-based glasses doping with halide. DSC curves indicate that all glass samples have good thermal stabilities (ΔT > 100 °C) and the highest ΔT value corresponding to (Ge15Ga10Te75)85(NaI)15 glass is 120 °C which is 8 °C greater than that of Ge–Ga–Te host glass. The infrared spectra manifest Ge–Ga–Te–NaI chalcogenide glass system has a wide infrared transmission window between 1.6 μm and 20 μm. Consequently, Ge–Ga–Te–NaI glasses can be a candidate material for far infrared optic imaging and bio-sensing application

Fabrication and characterization of Ge–Sb–Se–I glasses and fibers

International audienceChalcogenide glasses of the Ge20Sb5Se75−x I x (x = 0, 5, 10, 15, 20 at.%) system were prepared. This study was performed to examine some Ge–Sb–Se–I glass physical and optical properties, the structural evolution of the glass network, and the optical properties of the infrared glass fibers based on our previous studies. The variation process of the glass physical properties, such as transition temperature, glass density, and refractive index, was investigated from the glass of Ge20Sb5Se75 to the Ge20Sb5Se75−x I x glass series. The structural evolutions of these glasses were examined by Raman spectroscopy. The Ge20Sb5Se55I20 composition was selected for the preparation of the IR fiber. The Ge20Sb5Se55I20 glass was purified through distillation, and the intensity of the impurity absorption peaks caused by Ge–O, H2O, and Se–H was reduced or eliminated in the purified glasses. Then, Ge20Sb5Se55I20 chalcogenide glass fiber for mid-infrared transmission was fabricated using high-purity materials. The transmission loss of the Ge20Sb5Se55I20 fiber was greatly reduced compared with that of the Ge20Sb5Se75 glass fiber. The lowest losses obtained were 3.5 dB/m at 3.3 μm for Ge20Sb5Se75I20 fiber, which was remarkably improved compared with 48 dB/m of the unpurified Ge20Sb5Se75 fiber

Effect of Al on Microstructure and Properties of Hot-Rolled 2205 Dual Stainless Steel

The microstructure, mechanical properties, oxidation, and corrosion resistance of 2205 stainless steels without and with Al in a range of 0.5 to 2.5 wt.% were investigated in this paper. The results showed that the matrix phase transformed from austenite to ferrite. The volume fraction of the ferrite in the steels decreased at first and then increased and was the lowest in the steel with 0.5 wt.% Al. Most of the Al was dissolved in the ferrite and austenite phases in the steels. The ultimate tensile strength and elongation rate of the steels increased at first and then decreased with the increasing Al content, with the highest values in the steel with 0.5 wt.% Al. The yield strength of the steels slightly increased from 544 to 607 MPa due to the addition of Al. The oxidation rates of the steels with Al were much lower than that of the steel without Al, and the rate of the steel with 1.5 wt.% Al was the lowest, approximately 10 times lower than that of the steel without Al. The corrosion rates of the steels with 0.5 and 1.0 wt.% Al were slightly higher than that of the alloy without Al. In general, the steel with 1 wt.% Al had optimal properties

Mammalian systems biotechnology: An integrative framework for combining in silico modeling and multi-Omics datasets in different CHO parental cell lines

The increasing availability of multi-omics data from Chinese hamster ovary (CHO) cell cultures entails both opportunity and challenges toward next generation cell culture engineering. Herein, we present a comprehensive and integrative framework to systematically combine trancriptome, proteome, metabolome and glycome datasets in conjunction with a genome-scale metabolic model of CHO cells. We then apply the framework to compare and contrast the metabolic characteristics of the three commonly used parental cell lines (CHO-K1, CHO-DUKXB11 and CHO-DG44) so that “global” attributes of the parental hosts (e.g. growth related characteristics, glycosylation patterns, etc.) could be highlighted (Figure 1). The unique characteristics of the adherent against the suspension cell lines reveal that the latter are in an oxidative stress and that they differentially express genes/proteins associated with the lipid biosynthetic process. The unique transcriptomic and proteomic signatures of the different suspension cell lines, more relevant in an industrial context than the adherent, reflect the known historic divergence of the cell lines, i.e. the very different nature of the -DG44 cell line than the other two. Genes/proteins related with the purine nucleotide biosynthetic process (as expected, due to the Dhfr gene copy number differences), epigenetic regulation and programmed cell death present the major expression differences between the three parental cell lines. As far as the host N-glycome for each of the cell lines is concerned, it reveals similar profiles. Nevertheless, the cell lines present several differences in the expression of N-glycosylation related genes (e.g.Man2a1 and Fut8 are differentially expressed for -DG44 and Mgat4a for the -DXB11 cell line) and the pools of nucleotide sugar donors (-K1 presents higher UDP-Glc / UDP-Gal and CMP-sialic acid pools than -DG44; while -DG44 higher GDP-Fuc pools). Growth profiles of the various cell lines were also assessed and our results demonstrate that -K1 cells present significantly higher growth rate than the other two cell lines in suspension culture. Interestingly, adherent cells present a significantly faster growth profile than suspension cells that we attribute to the different media used for the two culture formats, i.e. to the presence of serum for adherent cells. The integrative framework also involves the use of the genome-scale metabolic model as a scaffold to map the multiomics datasets. Such an analysis allows us to readily pinpoint the heterogeneity in cellular metabolism between the multiple conditions and/or cell lines tested, as well as their correlations. Moreover, the correlation analysis of transcriptome and proteome for a given cell line revealed the plausible regulatory intracellular events that can be targeted for genetic engineering to achieve the enhanced productivity and quality of recombinant proteins in the context of bioprocessing. Interestingly, we identified many differences in the reactions associated with the N-glycan processing pathways for the various parental cell lines analyzed, which may be associated with different glycosylation capacity. Further investigation at the glycomics level may validate our hypothesis that choice of CHO hosts should be product-specific. It is expected that our results can serve as the golden standard for the comprehensive comparison of the various CHO cell lines used worldwide

SIRT6 Suppresses NFATc4 Expression and Activation in Cardiomyocyte Hypertrophy

NFATc4, a member from the Nuclear Factor of Activated T cells (NFATs) transcription factor family, plays a pivotal role in the development of cardiac hypertrophy. NFATc4 is dephosphorylated by calcineurin and translocated from the cytoplasm to the nucleus to regulate the expression of hypertrophic genes, like brain natriuretic polypeptide (BNP). The present study identified SIRT6, an important subtype of NAD+ dependent class III histone deacetylase, to be a negative regulator of NFATc4 in cardiomyocyte hypertrophy. In phenylephrine (PE)-induced hypertrophic cardiomyocyte model, overexpression of SIRT6 by adenovirus infection or by plasmid transfection repressed the protein and mRNA expressions of NFATc4, elevated its phosphorylation level, prevented its nuclear accumulation, subsequently suppressed its transcriptional activity and downregulated its target gene BNP. By contrast, mutant of SIRT6 without deacetylase activity (H133Y) did not demonstrate these effects, suggesting that the inhibitory effect of SIRT6 on NFATc4 was dependent on its deacetylase activity. Moreover, the effect of SIRT6 overexpression on repressing BNP expression was reversed by NFATc4 replenishment, whereas the effect of SIRT6 deficiency on upregulating BNP was recovered by NFATc4 silencing. Mechanistically, interactions between SIRT6 and NFATc4 might possibly facilitate the deacetylation of NFATc4 by SIRT6, thereby preventing the activation of NFATc4. In conclusion, the present study reveals that SIRT6 suppresses the expression and activation of NFATc4. These findings provide more evidences of the anti-hypertrophic effect of SIRT6 and suggest SIRT6 as a potential therapeutic target for cardiac hypertrophy