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Charlotte Lupton, Mohini Sengupta, Ruey-Kuang Cheng, Joanne Chia, Vatsala Thirumalai, Suresh Jesuthasan
Learning how to actively avoid a predictable threat involves two steps: recognizing the cue that predicts upcoming punishment and learning a behavioral response that will lead to avoidance. In zebrafish, ventral habenula (vHb) neurons have been proposed to participate in both steps by encoding the expected aversiveness of a stimulus. vHb neurons increase their firing rate as expectation of punishment grows but reduce their activity as avoidance learning occurs. This leads to changes in the activity of raphe neurons, which are downstream of the vHb, during learning...
May 2017: ENeuro
Eliana Castillo, Kellie Murphy, Julie van Schalkwyk
OBJECTIF: Examiner l'épidémiologie, l'histoire naturelle, l'évaluation et le traitement de l'infection au virus de l'hépatite B (VHB) durant la grossesse. Cela aidera les fournisseurs de soins obstétricaux à conseiller leurs patientes quant aux risques périnataux et aux options de prise en charge offertes aux femmes enceintes atteintes de l'hépatite B. ISSUES: Les éléments évalués comprennent les seuils de traitement antiviral contre le VHB pour la prévention de la transmission périnatale et pour les interventions effractives durant la grossesse pour les femmes atteintes de l'hépatite B...
March 2017: Journal of Obstetrics and Gynaecology Canada: JOGC, Journal D'obstétrique et Gynécologie du Canada: JOGC
Guoling Yin, Yu Yang, Feilong Song, Christophe Renard, Zhi-Min Dang, Chang-Yong Shi, Dongrui Wang
Dielectric elastomer generators (DEGs), which follow the physics of variable capacitors and harvest electric energy from mechanical work, have attracted intensive attention over the past decade. The lack of ideal dielectric elastomers, after nearly two decades of research, has become the bottleneck for DEGs' practical applications. Here, we fabricated a series of polyurethane-based ternary composites and estimated their potential as DEGs to harvest electric energy for the first time. Thermoplastic polyurethane (PU) with high relative permittivity (∼8) was chosen as the elastic matrix...
February 6, 2017: ACS Applied Materials & Interfaces
Tingzhen Mu, Maohua Yang, Jixiang Zhao, Moustafa Mohammed Sharshar, Jiangnan Tian, Jianmin Xing
OBJECTIVE: To construct efficient transformation and expression system and further improve desulfurizing activity of cells through expression of Vitreoscilla hemoglobin (VHb) in haloalkaliphilic Thialkalivibrio versutus SOB306. RESULTS: We transferred plasmids pKT230 and pBBR-sm(r) into T. versutus SOB306 via a conjugation method. We identified four promoters from among several predicted promoters by scoring for streptomycin resistance, and finally selected tac and p3 based on the efficiency of expression of red fluorescent protein (RFP)...
March 2017: Biotechnology Letters
Mariana Juárez, Claudia H González-De la Rosa, Elisa Memún, Juan-Carlos Sigala, Alvaro R Lara
Inefficient carbon metabolism is a relevant issue during the culture of mammalian cells for the production of biopharmaceuticals. Therefore, cell engineering strategies to improve the metabolic and growth performance of cell lines are needed. The expression of Vitreoscilla stercoraria hemoglobin (VHb) has been shown to significantly reduce overflow metabolism and improve the aerobic growth of bacteria. However, the effects of VHb on mammalian cells have been rarely studied. Here, the impact of VHb on growth and lactate accumulation during CHO-K1 cell culture was investigated...
March 2017: Biotechnology Journal
Xiaoliu Liu, Ping Zhu, Ruifan Jiang, Lingtian Wu, Xiaohai Feng, Sha Li, Hong Xu
Welan gum is a microbial polysaccharide produced by Sphingomonas sp. Its production is limited by the dissolved oxygen levels in the highly viscous fermentation. A strategy of heterologous expression of the Vitreoscilla hemoglobin gene in Sphingomonas sp. HT-1 was investigated to alleviate oxygen limitation and improve the yield of welan gum. Ultimately, the welan gum production increased from 25.3g/L to 34.6g/L, whereas the rheological behavior of welan gum solutions remained virtually unchanged. The transcriptional levels of the key genes in the electron transfer chain, TCA cycle and welan gum synthesis pathway, as well as ATP level revealed that the VHb expression in Sphingomonas sp...
January 20, 2017: Carbohydrate Polymers
Nigel E Bush, Derek J Smolenski, Lauren M Denneson, Holly B Williams, Elissa K Thomas, Steven K Dobscha
OBJECTIVE: The purpose of this study was to assess the impact of the Virtual Hope Box (VHB), a smartphone app to improve stress coping skills, suicidal ideation, and perceived reasons for living among patients at elevated risk of suicide and self-harm. METHODS: The authors conducted a parallel-group randomized controlled trial with two groups of U.S. service veterans in active mental health treatment who had recently expressed suicidal ideation. Between March 2014 and April 2015, 118 patients were enrolled in the study...
April 1, 2017: Psychiatric Services: a Journal of the American Psychiatric Association
Milan Shrestha, Gih-Keong Lau
This Letter presents a tunable window device based on microscopic wrinkling of a transparent elastomeric surface. "Crack-free" microscopic wrinkling of a 50-nm ZnO thin film is possible on a highly adhesive acrylic elastomer membrane (VHB 4910) upon partial release from a large radial pre-stretch of membrane. This ZnO-based tunable window device demonstrates reversible tunability between transparent and translucent states. At zero compression with a flat surface, the device is transparent with a 93% in-line transmittance at 550-nm wavelength...
October 1, 2016: Optics Letters
Alvaro R Lara, Karim E Jaén, Juan Carlos Sigala, Martina Mühlmann, Lars Regestein, Jochen Büchs
Oxygen limitation can be used as a simple environmental inducer for the expression of target genes. However, there is scarce information on the characteristics of microaerobic promoters potentially useful for cell engineering and synthetic biology applications. Here, we characterized the Vitreoscilla hemoglobin promoter (Pvgb) and a set of microaerobic endogenous promoters in Escherichia coli. Oxygen-limited cultures at different maximum oxygen transfer rates were carried out. The FMN-binding fluorescent protein (FbFP), which is a non-oxygen dependent marker protein, was used as a reporter...
October 7, 2016: ACS Synthetic Biology
Xiangchao Feng, Zhuo Ma, Jonathan V MacArthur, Christopher J Giuffre, Ashraf F Bastawros, Wei Hong
Inspired by the toughening mechanism of double-network (DN) hydrogels, a soft composite consisting of a fabric mesh and VHB tape layers was fabricated. The composite was as stiff as the fabric mesh, and as stretchable as the VHB tape. At certain compositions, the composite was significantly stronger and tougher than the base materials. The extensibility and toughness of the composite can be attributed to a damage delocalization mechanism similar to that of the DN gels. In the partially damaged regions, the fabric mesh fragmented into small islands, surrounded by the highly stretched VHB tapes...
October 3, 2016: Soft Matter
Zewang Guo, Xihua Zhao, Yuanzhi He, Tianxing Yang, Huifang Gao, Ganxi Li, Feixue Chen, Meijing Sun, Jung-Kul Lee, Liaoyuan Zhang
Acetoin (AC) is a volatile platform compound with various potential industrial applications. AC contains two stereoisomeric forms: (3S)-AC and (3R)-AC. Optically pure AC is important potential intermediate and widely used as a precursor to synthesize novel optically materials. In this study, chiral (3R)-AC production from meso-2,3-butanediol (meso-2,3-BD) was obtained using recombinant Escherichia coli cells co-expressing meso-2,3-butanediol dehydrogenase (meso-2,3-BDH), NADH oxidase (NOX) and hemoglobin protein (VHB) from Serratia sp...
October 6, 2016: Journal of Microbiology and Biotechnology
Taner Sar, Benjamin C Stark, Meltem Yesilcimen Akbas
Ethanol production from whey powder was investigated by using free as well as alginate immobilized E. coli and E. coli expressing Vitreoscilla hemoglobin (VHb) in both shake flask and fermenter cultures. Media with varying levels of whey (lactose contents of 3%, 5%, 8% or 15%) and yeast extract (0.3% or 0.5%) were evaluated with fermentation times of 48-96 h. Immobilization and VHb expression resulted in higher ethanol production with all media; the increases ranged from 2% to 89% for immobilization and from 2% to 182% for VHb expression...
March 4, 2017: Bioengineered
Tong-Xin Zhao, Mei Li, Xiang Zheng, Cheng-Hua Wang, Hong-Xin Zhao, Chong Zhang, Xin-Hui Xing
trans-4-Hydroxy-l-proline (Hyp) is a chiral amino acid conventionally produced by acid hydrolysis of animal collagen, a process which involves the bottleneck problems of low efficiency and heavy environmental pollution. Biotransformation of l-proline into Hyp using recombinant whole-cell biocatalysis with proline-4-hydroxylase (P4H) is an environmentally-friendly alternative method. Since biohydroxylation of proline by whole cells is a high-oxygen-demand process, oxygen transfer needs to be improved. To solve this problem, the Vitreoscilla hemoglobin gene (vgb) was integrated into the chromosome of recombinant Escherichia coli expressing the P4H gene originally from Dactylosporangium sp...
January 2017: Journal of Bioscience and Bioengineering
Di Liu, Ni Wan, Fuzhong Zhang, Yinjie J Tang, Stephen G Wu
Our recent (13) C-metabolic flux analysis ((13) C-MFA) study indicates that energy metabolism becomes a rate-limiting factor for fatty acid overproduction in E. coli strains (after "Push-Pull-Block" based genetic modifications). To resolve this bottleneck, Vitreoscilla hemoglobin (VHb, a membrane protein facilitating O2 transport) was introduced into a fatty-acid-producing strain to promote oxygen supply and energy metabolism. The resulting strain, FAV50, achieved 70% percent higher fatty acid titer than the parent strain in micro-aerobic shake tube cultures...
February 2017: Biotechnology and Bioengineering
Hyunwoo Yuk, Teng Zhang, German Alberto Parada, Xinyue Liu, Xuanhe Zhao
Inspired by mammalian skins, soft hybrids integrating the merits of elastomers and hydrogels have potential applications in diverse areas including stretchable and bio-integrated electronics, microfluidics, tissue engineering, soft robotics and biomedical devices. However, existing hydrogel-elastomer hybrids have limitations such as weak interfacial bonding, low robustness and difficulties in patterning microstructures. Here, we report a simple yet versatile method to assemble hydrogels and elastomers into hybrids with extremely robust interfaces (interfacial toughness over 1,000 Jm(-2)) and functional microstructures such as microfluidic channels and electrical circuits...
2016: Nature Communications
Rénovat Ntagirabiri, Belyse Munezero, Caritas Nahimana, Evariste Ndabaneze
INTRODUCTION: Hepatitis B virus infection (VHB) is a serious condition which can lead to serious complications, such as cirrhosis and hepato-cellular carcinoma (HCC). HBV genotypes greatly influence its evolution and the effectiveness of treatment. The aim was to evaluate the HBV genotypes and the evolutionary pathways of chronic HBsAG patients. METHODS: A cross-sectional study was conducted at the University Hospital of Kamenge and at the Digestive and liver diseases Center "CEMADIF" between June 2013 and Mai 2014...
2016: Pan African Medical Journal
Q Mo, H Zhang, Q Liu, X Tang, L Zhao, X Zan, Y Song
UNLABELLED: Oxygen deficiency is a critical limiting factor for nosiheptide production in Streptomyces actuosus during fermentation. To alleviate oxygen limitation and enhance the yield of nosiheptide, haemoprotein from Sinorhizobium meliloti (SmHb) was overexpressed in S. actuosus with overexpression of haemoglobin from Vitreoscilla (VHb) as a positive control. The expression of SmHb and VHb in S. actuosus was confirmed by SDS-PAGE and CO-difference spectra analysis. The results showed that S...
June 2016: Letters in Applied Microbiology
Huan-Jun Li, Yi-Long He, De-Huai Zhang, Tong-Hui Yue, Lu-Xi Jiang, Na Li, Jun-Wei Xu
The Vitreoscilla hemoglobin (VHb) gene was expressed in Ganoderma lucidum to enhance antitumor ganoderic acid (GA) production. The effects of VHb expression on the accumulation of GAs and lanosterol (intermediate) and the transcription of GA biosynthesis genes were also investigated. In VHb-expressing G. lucidum, the maximum concentrations of four individual GAs (GA-S, GA-T, GA-Mk and GA-Me) were 19.1±1.8, 34.6±2.1, 191.5±13.1 and 45.2±2.8μg/100mg dry weight, respectively, which were 1.4-, 2.2, 1.9- and 2...
June 10, 2016: Journal of Biotechnology
Jianrong Wang, Yangyuan Li, Danni Liu
A series of strategies were applied to improve expression level of recombinant endo-β-1,4-xylanase from Aspergillus usamii (A. usamii) in Pichia pastoris (P. pastoris). Firstly, the endo-β-1,4-xylanase (xynB) gene from A. usamii was optimized for P. pastoris and expressed in P. pastoris. The maximum xylanase activity of optimized (xynB-opt) gene was 33500 U/mL after methanol induction for 144 h in 50 L bioreactor, which was 59% higher than that by wild-type (xynB) gene. To further increase the expression of xynB-opt, the Vitreoscilla hemoglobin (VHb) gene was transformed to the recombinant strain containing xynB-opt...
2016: BioMed Research International
Wenwen Zhang, Zhaohui Chen, Mengmeng Wu, Zhong Shi, Feng Zhu, Guoqiang Li, Ting Ma
OBJECTIVE: To improve the production of welan gum and obtain a carotenoid-free strain while reducing the fermentation and post-treatment costs. RESULTS: The vitreoscilla globin (vgb) gene combined with the β-galactosidase (lacZ) promoter was inserted into the phytoene synthase (crtB) gene region of the chromosome in Alcaligenes sp. ATCC31555. When the recombinant strain was grown in a 5 l fermentor, welan gum was produced at 24 ± 0.4 g l(-1) compared to 21 g ± 0...
June 2016: Biotechnology Letters
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