Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Functional conservation and divergence of Miscanthus lutarioriparius GT43 gene family in xylan biosynthesis
No full textBackground: Xylan is the most abundant un-cellulosic polysaccharides of plant cell walls. Much progress in xylan biosynthesis has been gained in the model plant species Arabidopsis. Two homologous pairs Irregular Xylem 9 (IRX9)/9L and IRX14/14L from glycosyltransferase (GT) family 43 have been proved to play crucial roles in xylan backbone biosynthesis. However, xylan biosynthesis in grass such as Miscanthus remains poorly understood
Genetically Engineered Phage-Templated MnO2 Nanowires: Synthesis and Their Application in Electrochemical Glucose Biosensor Operated at Neutral pH Condition
No full textTo conveniently obtain one-dimensional MnO2 nanowires (NWs) with controlled structure and unique properties for electron transfer, the genetically engineered M13 phages were used as templates for precise nucleation and growth of MnO2 crystals in filamentous phage scaffolds, via the spontaneous oxidation of Mn2+ in alkaline solution. It was found that the morphology of NWs could be tailored by the surface charge of M13 mutants. MnO2 crystals were uniformly distributed on the surface of negatively charged tetraglutamate-fused phage (M13-E4), significantly different from irregular MnO2 agglomeration on the weakly negatively charged wild-type phage and positively charged tetraarginine-fused phage. The as-synthesized M13-E4@MnO2 NWs could catalyze the electro-oxidation of H2O2 at neutral pH. To demonstrate the superiority of the electrocatalytic activity in the solution containing plenty of chloride ions at neutral pH, both glucose oxidase and as-prepared MnO2 NWs were used for fabricating the glucose biosensor. The proposed biosensor showed a wide linear range (5 mu M to 2 mM glucose), a low limit of detection of 1.8 mu M glucose (S/N = 3), good interassay and intra-assay reproducibility and satisfactory storage stability. Due to the superiorities of synthesis and electrochemical performance, the as-prepared MnO2 NWs are promising for applications in electrocatalysis, electrochemical sensor, and supercapacitor
Novel donor-acceptor polymers containing o-fluoro-p-alkoxyphenyl-substituted benzo[1,2-b:4,5-b ']dithiophene units for polymer solar cells with power conversion efficiency exceeding 9%
No full textIn this work, a new electron-rich building block, o-fluoro-p-alkoxyphenyl-substituted benzo[1,2-b:4,5-b'] dithiophene (BDT) unit, has been used to construct donor (D)-acceptor (A) conjugated copolymers with electron-deficient units 5,6-difluoro-4,7-di(4-(2-ethylhexyl)-2-thienyl)-2,1,3-benzothiadiazole (C8DTBTff) and 5,6-difluoro-4,7-di(4-hexyl-2-thienyl)-2,1,3-benzothiadiazole (C6DTBTff), named P-o-FBDTP-C8DTBTff (P2) and P-o-FBDTP-C6DTBTff (P3), respectively. The experimental results indicate that the incorporation of fluorine into the ortho-position of the alkoxyphenyl substituted BDT unit can enable its resultant polymer to efficiently tune the energy levels and improve the mobility of the derived bulk heterojunction layer, which results in a much higher power conversion efficiency (PCE) of P2 (8.10%). Moreover, replacing the 2-ethylhexyl chains on the DTBTff unit with hexyl chains can improve the planarity of the conjugated backbone of the polymer, which makes the P3/PC71BM blends exhibit higher carrier mobility than P2/PC71BM. Finally, a PCE of 9.02% for the device of P3 is obtained without any additive treatment, which is the highest value achieved for the widely reported D-A polymers with fluorine substituted BDT as the electron-donor unit in single junction polymer solar cells
Engineering Escherichia coli for high-yield geraniol production with biotransformation of geranyl acetate to geraniol under fed-batch culture (vol 9, 58, 2016)
No full textCetylpyridinium chloride mouth rinses alleviate experimental gingivitis by inhibiting dental plaque maturation
No full textOral rinses containing chemotherapeutic agents, such as cetylpyridinium chloride (CPC), can alleviate plaque-induced gingival infections, but how oral microbiota respond to these treatments in human population remains poorly understood. Via a double blinded, randomised controlled trial of 91 subjects, the impact of CPC-containing oral rinses on supragingival plaque was investigated in experimental gingivitis, where the subjects, after a 21-day period of dental prophylaxis to achieve healthy gingivae, received either CPC rinses or water for 21 days. Within-subject temporal dynamics of plaque microbiota and symptoms of gingivitis were profiled via 16S ribosomal DNA gene pyrosequencing and assessment with the Mazza gingival index. Cetylpyridinium chloride conferred gingival benefits, as progression of gingival inflammation resulting from a lack of dental hygiene was significantly slower in the mouth rinse group than in the water group due to inhibition of 17 gingivitis-enriched bacterial genera. Tracking of plaque alpha and beta diversity revealed that CPC treatment prevents acquisition of new taxa that would otherwise accumulate but maintains the original biodiversity of healthy plaques. Furthermore, CPC rinses reduced the size, local connectivity and microbiota-wide connectivity of the bacterial correlation network, particularly for nodes representing gingivitis enriched taxa. The findings of this study provide mechanistic insights into the impact of oral rinses on the progression and maturation of dental plaque in the natural human population
Single cell stable isotope probing in microbiology using Raman microspectroscopy
No full textMicrobial communities are essential for most ecosystem processes and interact in highly complex ways with virtually all eukaryotes. Thus, a detailed understanding of the function of such communities is a fundamental prerequisite for microbial ecologists, applied microbiologists and microbiome researchers. Using single cell Raman microspectroscopy, biochemical fingerprints of individual microbial cells can be obtained in an externally label-free and non-destructive manner. If combined with stable isotope probing (SIP), Raman spectroscopy can directly reveal functions of single microorganisms in their natural habitat. This review provides an update on various SIP-approaches suitable for combination with different Raman scattering techniques and illustrates how single cell Raman SIP can be directly combined with the omics-centric analysis pipelines to investigate microbial communities
Ultrafast Dynamics of Photongenerated Holes at a CH3OH/TiO2 Rutile Interface
No full textPhotogenerated charge carrier dynamics near molecule/TiO2 interfaces are important for the photocatalytic and photovoltaic processes. To understand this fundamental aspect, we performed a time-domain ab initio nonadiabatic molecular dynamics study of the photogenerated hole dynamics at the CH3OH/rutile TiO2(110) interface. We studied the forward and reverse hole transfer between TiO2 and CH3OH as well as the hole energy relaxation to the valence band maximum. First, we show that the hole-trapping ability of CH3OH depends strongly on the adsorption structure. Only when the CH3OH is deprotonated to form chemisorbed CH3O will 45% of the hole be trapped by the molecule. Second, we find that strong fluctuations of the HOMO energies of the adsorbed molecules induced by electron phonon coupling provide additional channels, which accelerate the hole energy relaxation. Third, we demonstrate that the charge transfer and energy relaxation processes depend significantly on temperature. When the temperature decreases from 100 to 30 K, the forward hole transfer and energy relaxation processes are strongly suppressed because of the reduction of phonon occupation. These results indicate that the molecule/TiO2 energy level alignment, thermal excitation of a phonon, and electron phonon coupling are the key factors that determine the photogenerated hole dynamics. Our studies provide valuable insights into the photogenerated charge and energy transfer dynamics at molecule/semiconductor interfaces
Facile One-Pot Conversion of Petroleum Asphaltene to High Quality Green Fluorescent Graphene Quantum Dots and Their Application in Cell Imaging
No full textBenefiting from the natural nano-size graphene-structure in natural asphaltene material, a facile one-pot route, mild chemical oxidation of low-value petroleum asphaltene followed by routine ammonium neutralization, is presented to produce high quality graphene quantum dots (GQDs). The asphaltene-derived GQDs possess a variety of oxygen-containing and nitrogen-containing functional groups such as carboxyl, hydroxyl, amine, and nitro groups. They present such excellent fluorescence properties as stable ability to retain strong green fluorescence within a relative broad excitation range in a bio-suitable pH range of 4-7, high photoluminescence quantum yield of 18% and good fluorescent stability against photobleaching. And they are much smaller and thinner than most reported GQDs, displaying good biocompatibility with low cytotoxicity, effective cellular uptake, and excellent fluorescent probe performance for cancer cell imaging
NaV3(PO4)(3)/C nanocomposite as novel anode material for Na-ion batteries with high stability
No full textAnode materials with long cycling life and rate capability have remained a great challenge for sodium ion batteries. Herein, a vanadium-based orthophosphate, NaV3(PO4)(3)/C nanocomposite has been investigated as a novel anode material for Na-ion batteries. The electrochemical performance of NaV3(PO4)(3)/C nanocomposite is evaluated in Na-half cell, which delivers a reversible capacity of 146 mA h g(-1) at the charging/discharging rate of 1 C, and remarkable rate capability. EIS, XPS and in-situ XRD are performed to give the insight into interfacial property of electrode and structural evolution of material during cycling. The excellent cycling stability could be attributed to stable interface at higher cutoff voltage and slight change of structure with intercalation/deintercalation of Nat Moreover, we achieve a Na-ion full battery with long term cycle life based on NaV3(PO4)(3)/C anode and Na3V2(PO4)(3)/C cathode, retaining 80% of initial capacity after 1000 cycles at charging/discharging rate of 5 C, suggesting the feasibility of the as-obtained materials applied as a promising candidate for anode of Na-ion batteries. (C) 2016 Elsevier Ltd. All rights reserved
Two T-Shaped Donor-Acceptor Small Molecules Based on 4,9-Di(thiophen-2-yl)naphtho[2,3-b]thiophene for Solution-Processed Organic Solar Cells
No full textTwo novel T-shaped -conjugated small molecules of DTNT-3DPP and DTNT(DPP-PN)(3) with 4,9-di(thiophen-2-yl)naphtho[2,3-b]thiophene (DTNT) as the donor core and diketopyrrolopyrrole (DPP) as acceptor arms, in the latter case incorporating phenanthrene (PN) units, have been designed and synthesized. The effects of the central core and terminal units on the optical, thermal, electrochemical, and photovoltaic properties have been investigated. It was found that DTNT-3DPP and DTNT(DPP-PN)(3) exhibit better light-harvesting and charge-transport properties than triphenylamine (TPA)-based star-shaped molecules. DTNT-3DPP and DTNT(DPP-PN)(3) were used as donor materials and methyl [6,6]-phenyl-C-71-butyrate (PC71BM) as the acceptor for the fabrication of solution-processed bulk heterojunction (BHJ) solar cells. The power conversion efficiencies (PCEs) of solar cells based on DTNT-3DPP and DTNT(DPP-PN)(3) are 3.47 and 3.69%, respectively. These PCEs are higher than those of the corresponding TPA-based solar cells (1.91 and 3.67%). Our work indicates that the planar DTNT unit can improve the photovoltaic properties of organic small molecules relative to those of the TPA unit