Metal–Organic Framework Derived Hierarchical Porous Anatase TiO₂ as a Photoanode for Dye-Sensitized Solar Cell

Metal–organic frameworks (MOFs) have been generating a great deal of interest due to their high specific surface area, regular pore structure, and adjustable aperture. However, only a few studies explored their application in the field of photovoltaic devices. In the present work, MIL-125­(Ti), one kind of MOFs, was investigated as the precursor for TiO₂ photoanode of dye-sensitized solar cells for the first time. Herein, pure anatase TiO₂ with a hierarchical structure was synthesized through the decomposition of MIL-125­(Ti), which avoids the use of templates and fussy operation of sol–gel methods. The obtained TiO₂ has a specific surface area of 147 m² g^–1 and a mean pore size value of 10 nm. When used as a photoanode material in dye-sensitized solar cells, the device gave rise to an overall energy conversion efficiency of 7.20%, which is better than the performance of the P25 based photoanode

The Riemerella anatipestifer M949_RS01035 gene is involved in bacterial lipopolysaccharide biosynthesis

Abstract In this study, the Riemerella anatipestifer mutant strain RA1062 was obtained by screening a random Tn4351 transposon mutant library. The mutant strain was unreactive with the anti-CH3 lipopolysaccharide monoclonal antibody, as demonstrated with an enzyme-linked immunosorbent assay, and its M949_RS01035 gene was inactivated. When cultured in trypticase soy broth, the late stage growth of the mutant RA1062 was significantly decreased. The mutant RA1062 was stained with crystal violet and presented a rough lipopolysaccharide phenotype, which differed from that of the wild-type strain CH3, suggesting that deletion of the M949_RS01035 gene resulted in defective lipopolysaccharide. Silver staining and Western blot analyses further confirmed that the RA1062 lipopolysaccharide had a deficiency in ladder-like binding pattern, as compared to lipopolysaccharide of the wild-type CH3 strain. In addition, the mutant RA1062 showed a higher susceptibility to complement-dependent killing, increased bacterial adhesion and invasion capacities to Vero cells, decreased blood bacterial loads, and attenuated virulence in infected ducks, when compared to the wild-type strain CH3. Moreover, RNA-Seq and real-time polymerase chain reaction analyses indicated that two genes were up-regulated and two were down-regulated in the mutant RA1062 genome. Furthermore, an animal protection experiment showed that immunization of ducks with inactivated RA1062 bacterin conferred effective cross-protection against challenge with the virulent R. anatipestifer serotypes 1, 2, and 10. This study presents evidence that the M949_RS01035 gene is involved in bacterial phenotype, virulence, and gene regulation in R. anatipestifer. The mutant strain RA1062 could be used as a cross-protective vaccine candidate

ERPs and oscillations during encoding predict retrieval of digit memory in superior mnemonists.

Previous studies have consistently demonstrated that superior mnemonists (SMs) outperform normal individuals in domain-specific memory tasks. However, the neural correlates of memory-related processes remain unclear. In the current EEG study, SMs and control participants performed a digit memory task during which their brain activity was recorded. Chinese SMs used a digit-image mnemonic for encoding digits, in which they associated 2-digit groups with images immediately after the presentation of each even-position digit in sequences. Behaviorally, SMs' memory of digit sequences was better than the controls'. During encoding in the study phase, SMs showed an increased right central P2 (150-250ms post onset) and a larger right posterior high-alpha (10-14Hz, 500-1720ms) oscillation on digits at even-positions compared with digits at odd-positions. Both P2 and high-alpha oscillations in the study phase co-varied with performance in the recall phase, but only in SMs, indicating that neural dynamics during encoding could predict successful retrieval of digit memory in SMs. Our findings suggest that representation of a digit sequence in SMs using mnemonics may recruit both the early-stage attention allocation process and the sustained information preservation process. This study provides evidence for the role of dynamic and efficient neural encoding processes in mnemonists.info:eu-repo/semantics/publishe

Riemerella anatipestifer M949_1360 Gene Functions on the Lipopolysaccharide Biosynthesis and Bacterial Virulence.

Riemerella anatipestifer causes septicemic and exudative diseases in poultry, resulting in major economic losses to the duck industry. Lipopolysaccharide (LPS), as an important virulence factor in Gram-negative bacteria, can be recognized by the immune system and plays a crucial role in many interactions between bacteria and animal hosts. In this study, we screened out one LPS defective mutant strain RAΔ604 from a random transposon mutant library of R. anatipestifer serotype 1 strain CH3, which did not react with the anti-CH3 LPS monoclonal antibody 1C1 in an indirect enzyme-linked immunosorbent assay. Southern blot analysis confirmed that the genome of RAΔ604 contained a single Tn4351 insert. Then, we found that the M949_1360 gene was inactivated by insertion of the transposon. Using silver staining and western blot analyses, we found that the LPS pattern of RAΔ604 was defective, as compared with that of the wild-type (WT) strain CH3. The mutant strain RAΔ604 showed no significant influence on bacterial growth, while bacterial counting and Live/dead BacLight Bacterial Viability staining revealed that bacterial viability was decreased, as compared with the WT strain CH3. In addition, the abilities of the mutant strain RAΔ604 to adhere and invade Vero cells were significantly decreased. Animal studies revealed that the virulence of the mutant strain RAΔ604 was decreased by more than 200-fold in a duck infection model, as compared with the WT strain CH3. Furthermore, immunization with live bacteria of the mutant strain RAΔ604 protected 87.5% ducks from challenge with R. anatipestifer serotype 1 strain WJ4, indicating that the mutant strain RAΔ604 could be used as a potential vaccine candidate in the future

Strains, plasmids, and primers used in this study.

<p>Strains, plasmids, and primers used in this study.</p

LPS structure analysis.

<p>(A) Silver staining of purified LPS. Each lane contained 0.5 μg of purified LPS. Lane M: Prestained Protein Ladder (Thermo Fisher Scientific, Inc.); Lane 1: <i>R</i>. <i>anatipestifer</i> CH3 LPS; Lane 2: The mutant strain RAΔ604 LPS; Lane 3: The complementation strain cRAΔ604 LPS. (B) Western blot analysis. Each lane contained 10⁸−10⁹ CFU of bacteria in 10 μl volume. After SDS-PAGE and transferred to a NC membrane, the NC membrane was incubated with anti-CH3 LPS MAb 1C1 (1:2000 dilution). Lane M: Prestained Protein Ladder (Thermo Fisher Scientific, Inc.); Lane 1: <i>R</i>. <i>anatipestifer</i> WT strain CH3; Lane 2: The mutant strain RAΔ604 LPS; Lane 3: The complementation strain cRAΔ604.</p

<i>Riemerella anatipestifer</i> M949_1360 Gene Functions on the Lipopolysaccharide Biosynthesis and Bacterial Virulence - Fig 1

<p><b>Characterization of <i>R</i>. <i>anatipestifer</i> mutant strain RAΔ604 and complementation strain cRAΔ604</b> (A) Southern blot analysis. Lane 1: PEP<i>4351</i> (positive control); Lane 2: <i>R</i>. <i>anatipestifer</i> CH3 (negative control); Lane 3: mutant strain RAΔ604. (B) Schematic chart of Tn<i>4351</i> insertion in RAΔ604 chromosome at 810 bp of the M949_1360 gene. The flanking genes M949_1359, M949_1361, and M949_1362 were annotated as hypothetical protein, glycosyl transferase group 1 and lipopolysaccharide-modifying protein respectively. (C) qPCR analysis. Changes in mRNA levels are expressed as fold expression and calculated using the comparative CT (2^-ΔΔCT) method. The expression of M949_1360 was inactivated in RAΔ604. However, no significant difference was shown in expression levels of M949_1359 and M949_1361 between <i>R</i>. <i>anatipestifer</i> CH3 and RAΔ604 (ns, <i>p</i> > 0.05). Error bars represent standard deviations from three replicates (***, <i>p</i> < 0.01). (D) Identification of the complementation strain cRAΔ604 by PCR. Takara DL2000 marker; lanes 1–3: <i>R</i>. <i>anatipestifer</i> 16S rRNA was amplified from the WT strain CH3 (lane 1), the mutant strain RAΔ604 (lane 2), and the complementation strain cRAΔ604 (lane 3), showing a 744-bp fragment of 16S rRNA; lanes 4–6: 963-bp fragment of M949_1360 gene was amplified from the WT strain CH3 (lane 4), and the complementation strain cRAΔ604 (lane 6), no 963-bp fragment of M949_1360 gene was amplified from the mutant strain RAΔ604 (lane 5); lanes 7–11: a 459-bp fragment of <i>R</i>. <i>anatipestifer</i> dnaB gene, but not a <i>E</i>. <i>coli</i> phoA gene was amplified from the WT strain CH3 (lane 7), the mutant strain RAΔ604 (lane 8) and the complementation strain cRAΔ604 (lane 9); lane 10: a 720-bp fragment of <i>E</i>. <i>coli</i> phoA gene was amplified from <i>E</i>. <i>coli</i> S17-1 strain; lane 11: distilled water, as a negative control.</p

Bacterial adherence and invasion assays.

<p>(A) Adherence assay. (B) Invasion assay. Each point represents the mean ± standard deviation. Both adherence and invasion capacities of the mutant strain RAΔ604 were decreased, as compared with those of <i>R</i>. <i>anatipestifer</i> WT strain CH3 (***, <i>p</i> < 0.01; **, <i>p</i> < 0.05). The complementation strain cRAΔ604 partially recovered adherence and invasion capacities (ns, <i>p</i> > 0.05).</p