bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular basis of dimer formation during the biosynthesis of benzofluorene-containing atypical angucyclines
Authors: Huang Chunshuai , Yang Chunfang , Zhang Wenjun , Zhang Liping , De Bidhan Chandra , Zhu Yiguang , Jiang Xiaodong , Fang Chunyan , Zhang Qingbo , Yuan Cheng-Shan , Liu Hung-wen , Zhang Changsheng
Published: May 2018

Lomaiviticin A and difluostatin A are benzofluorene-containing aromatic polyketides in the atypical angucycline family. Although these dimeric compounds are potent antitumor agents, how nature constructs their complex structures remains poorly understood. Herein, we report the discovery of a number of fluostatin type dimeric aromatic polyketides with varied C−C and C−N coupling patterns. We also demonstrate that these dimers are not true secondary metabolites, but are instead derived from non-enzymatic deacylation of biosynthetic acyl fluostatins. The non-enzymatic deacylation proceeds via a transient quinone methide like intermediate which facilitates the subsequent C–C/C−N coupled dimerization. Characterization of this unusual property of acyl fluostatins explains how dimerization takes place, and suggests a strategy for the assembly of C–C and C–N coupled aromatic polyketide dimers. Additionally, a deacylase FlsH was identified which may help to prevent accumulation of toxic quinone methides by catalyzing hydrolysis of the acyl group.
Author Correction: A B-ARR-mediated cytokinin transcriptional network directs hormone cross-regulation and shoot development
Authors: Xie Mingtang , Chen Hongyu , Huang Ling , O’Neil Ryan C. , Shokhirev Maxim N. , Ecker Joseph R.
Published: May 2018

The original version of this Article contained an error in Fig. 3. Panel b was inadvertently duplicated and the correct panel c was originally omitted. This error has been corrected in both the PDF and HTML versions of the Article.
Zinc ion flux during mammalian sperm capacitation
Authors: Kerns Karl , Zigo Michal , Drobnis Erma Z. , Sutovsky Miriam , Sutovsky Peter
Published: May 2018

Sperm capacitation, the ultimate maturation event preparing mammalian spermatozoa for fertilization, was first described in 1951, yet its regulatory mechanisms remain poorly understood. The capacitation process encompasses an influx of bicarbonate and calcium ions, removal of decapacitating factors, changes of pH and sperm proteasomal activities, and the increased protein tyrosine phosphorylation. Here, we document a novel biological phenomenon of a unique zinc (Zn2+) ion redistribution associated with mammalian sperm in vitro capacitation (IVC). Using image-based flow cytometry (IBFC), we identified four distinct types of sperm zinc ion distribution patterns (further zinc signature) and their changes during IVC. The zinc signature was altered after sperm capacitation, reduced by proteasomal inhibitors, removed by zinc chelators, and maintained with addition of external ZnCl2. These findings represent a fundamental shift in the understanding of mammalian fertilization, paving the way for improved semen analysis, in vitro fertilization (IVF), and artificial insemination (AI).
Coil-globule transitions drive discontinuous volume conserving deformation in locally restrained gels
Authors: Yamamoto Tetsuya , Masubuchi Yuichi , Doi Masao
Published: May 2018

The equilibrium volume of a thermoresponsive polymer gel changes dramatically across a temperature due to the coil–globule transitions of the polymers. When cofacially oriented nanosheets are embedded in such a gel, the composite gel deforms at the temperature, without changing the volume, and the response time is considerably shorter. We here theoretically predict that the deformation of the composite gel results from the fact that the nanosheets restrain the deformation of some polymers, while other polymers deform relatively freely. The unrestrained polymers collapse due to the coil–globule transitions and this generates the solvent flows to the restrained regions. The response time of this process is rather fast because solvent molecules travel only by the distance of the size of a nanosheet, instead of permeating out to the external solution. This concept may provide insight in the physics of composite gels and the design of thermoresponsive gels of fast response.
Author Correction: Biochemical phosphates observed using hyperpolarized 31P in physiological aqueous solutions
Authors: Nardi-Schreiber Atara , Gamliel Ayelet , Harris Talia , Sapir Gal , Sosna Jacob , Gomori J. Moshe , Katz-Brull Rachel
Published: May 2018

The original version of the Supplementary Information associated with this Article contained an error in Supplementary Figure 2 and Supplementary Figure 5 in which the 31P NMR spectral lines were missing. The HTML has been updated to include a corrected version of the Supplementary Information.
ON-OFF receptive fields in auditory cortex diverge during development and contribute to directional sweep selectivity
Authors: Sollini Joseph , Chapuis Gaëlle A. , Clopath Claudia , Chadderton Paul
Published: May 2018

Neurons in the auditory cortex exhibit distinct frequency tuning to the onset and offset of sounds, but the cause and significance of ON and OFF receptive field (RF) organisation are not understood. Here we demonstrate that distinct ON and OFF frequency tuning is largely absent in immature mouse auditory cortex and is thus a consequence of cortical development. Simulations using a novel implementation of a standard Hebbian plasticity model show that the natural alternation of sound onset and offset is sufficient for the formation of non-overlapping adjacent ON and OFF RFs in cortical neurons. Our model predicts that ON/OFF RF arrangement contributes towards direction selectivity to frequency-modulated tone sweeps, which we confirm by neuronal recordings. These data reveal that a simple and universally accepted learning rule can explain the organisation of ON and OFF RFs and direction selectivity in the developing auditory cortex.
CD11c+ M1-like macrophages (MΦs) but not CD206+ M2-like MΦ are involved in folliculogenesis in mice ovary
Authors: Ono Yosuke , Nagai Miwako , Yoshino Osamu , Koga Kaori , Nawaz Allah , Hatta Hideki , Nishizono Hirofumi , Izumi Gentaro , Nakashima Akitoshi , Imura Johji , Tobe Kazuyuki , Fujii Tomoyuki , Osuga Yutaka , Saito Shigeru
Published: May 2018

Macrophages (MΦs) are involved in folliculogenesis and ovulation. However, it is unknown which type of MΦ, M1 or M2, plays a more essential role in the ovary. CD206 or CD11c diphtheria toxin receptor transgenic (DTR) mice, which enable depletion of CD206+ M2 MΦs and CD11c+ MΦ or CD11c+ Dendritic cells (DCs), respectively, were used. Oocytes were used for in vitro fertilization and embryo transfer. In vitro fertilized embryos derived from M2 MΦ depleted oocytes were transferred to pseudo pregnant wild type mice. CD11c DTR mice were also used to investigate the role of CD11c cells, M1 MΦ and DCs in folliculogenesis. In WT mice, the proportion of CD206+ M2-like MΦs was not increased in follicular induction, while that of CD11c+ M1-like MΦs was increased. In CD206 DTR mice, folliculogenesis was normal and the ovulation number, fertilization rate, and implantation rate were similar to those in WT mice. In CD11c DTR mice, folliculogenesis was impaired with ovarian hemorrhage and the staining of platelet derived growth factor-receptor β (PDGF-Rβ), a marker of pericytes, and CD34, a marker of endothelial cells, was reduced. CD11c+ cells, M1 MΦs or DCs, may be involved in folliculogenesis, while M2 MΦs are not involved in folliculogenesis.
Developmental temperature has persistent, sexually dimorphic effects on zebrafish cardiac anatomy
Authors: Dimitriadi Anastasia , Beis Dimitris , Arvanitidis Christos , Adriaens Dominique , Koumoundouros George
Published: May 2018

Over the next century, climate change of anthropogenic origin is a major threat to global biodiversity. We show here that developmental temperature can have significant effects on zebrafish cardiac anatomy and swimming performance. Zebrafish embryos were subjected to three developmental temperature treatments (TD = 24, 28 or 32 °C) up to metamorphosis and then all maintained under common conditions (28 °C) to adulthood. We found that developmental temperature affected cardiac anatomy of juveniles and adults even eight months after the different thermal treatments had been applied. The elevation of TD induced a significant increase of the ventricle roundness in juvenile (10% increase) and male (22% increase), but not in female zebrafish. The aerobic exercise performance of adult zebrafish was significantly decreased as TD elevated from 24 to 32 °C. Gene expression analysis that was performed at the end of the temperature treatments revealed significant up-regulation of nppa, myh7 and mybpc3 genes at the colder temperature. Our work provides the first evidence for a direct link between developmental temperature and cardiac form at later life-stages. Our results also add to the emerging rationale for understanding the potential effects of global warming on how fish will perform in their natural environment.
Enabling STD-NMR fragment screening using stabilized native GPCR: A case study of adenosine receptor
Authors: Igonet Sébastien , Raingeval Claire , Cecon Erika , Pučić-Baković Maja , Lauc Gordan , Cala Olivier , Baranowski Maciej , Perez Javier , Jockers Ralf , Krimm Isabelle , Jawhari Anass
Published: May 2018

Structural studies of integral membrane proteins have been limited by the intrinsic conformational flexibility and the need to stabilize the proteins in solution. Stabilization by mutagenesis was very successful for structural biology of G protein-coupled receptors (GPCRs). However, it requires heavy protein engineering and may introduce structural deviations. Here we describe the use of specific calixarenes-based detergents for native GPCR stabilization. Wild type, full length human adenosine A2A receptor was used to exemplify the approach. We could stabilize native, glycosylated, non-aggregated and homogenous A2AR that maintained its ligand binding capacity. The benefit of the preparation for fragment screening, using the Saturation-Transfer Difference nuclear magnetic resonance (STD-NMR) experiment is reported. The binding of the agonist adenosine and the antagonist caffeine were observed and competition experiments with CGS-21680 and ZM241385 were performed, demonstrating the feasibility of the STD-based fragment screening on the native A2A receptor. Interestingly, adenosine was shown to bind a second binding site in the presence of the agonist CGS-21680 which corroborates published results obtained with molecular dynamics simulation. Fragment-like compounds identified using STD-NMR showed antagonistic effects on A2AR in the cAMP cellular assay. Taken together, our study shows that stabilization of native GPCRs represents an attractive approach for STD-based fragment screening and drug design.
Hot-Hole Cooling Controls the Initial Ultrafast Relaxation in Methylammonium Lead Iodide Perovskite
Authors: Hedley Gordon J. , Quarti Claudio , Harwell Jonathon , Prezhdo Oleg V. , Beljonne David , Samuel Ifor D. W.
Published: May 2018

Understanding the initial ultrafast excited state dynamics of methylammonium lead iodide (MAPI) perovskite is of vital importance to enable its fullest utilisation in optoelectronic devices and the design of improved materials. Here we have combined advanced measurements of the ultrafast photoluminescence from MAPI films up to 0.6 eV above the relaxed excited state with cutting-edge advanced non-adiabatic quantum dynamics simulations, to provide a powerful unique insight into the earliest time behaviour in MAPI. Our joint experimental-theoretical approach highlights that the cooling of holes from deep in the valence band to the valence band edge is fast, occurring on a 100–500 fs timescale. Cooling of electrons from high in the conduction band to the conduction band edge, however, is much slower, on the order of 1–10 ps. Density of states calculations indicate that excited states with holes deep in the valence band are greatly favoured upon photoexcitation, and this matches well with the fast (100–500 fs) formation time for the relaxed excited state observed in our ultrafast PL measurements. Consequently we are able to provide a complete observation of the initial excited state evolution in this important prototypical material.
Sorting Five Human Tumor Types Reveals Specific Biomarkers and Background Classification Genes
Authors: Roche Kimberly E. , Weinstein Marvin , Dunwoodie Leland J. , Poehlman William L. , Feltus Frank A.
Published: May 2018

We applied two state-of-the-art, knowledge independent data-mining methods – Dynamic Quantum Clustering (DQC) and t-Distributed Stochastic Neighbor Embedding (t-SNE) – to data from The Cancer Genome Atlas (TCGA). We showed that the RNA expression patterns for a mixture of 2,016 samples from five tumor types can sort the tumors into groups enriched for relevant annotations including tumor type, gender, tumor stage, and ethnicity. DQC feature selection analysis discovered 48 core biomarker transcripts that clustered tumors by tumor type. When these transcripts were removed, the geometry of tumor relationships changed, but it was still possible to classify the tumors using the RNA expression profiles of the remaining transcripts. We continued to remove the top biomarkers for several iterations and performed cluster analysis. Even though the most informative transcripts were removed from the cluster analysis, the sorting ability of remaining transcripts remained strong after each iteration. Further, in some iterations we detected a repeating pattern of biological function that wasn’t detectable with the core biomarker transcripts present. This suggests the existence of a “background classification” potential in which the pattern of gene expression after continued removal of “biomarker” transcripts could still classify tumors in agreement with the tumor type.
Rapid in situ assessment of Cu-ion mediated effects and antibacterial efficacy of copper surfaces
Authors: Rosenberg Merilin , Vija Heiki , Kahru Anne , Keevil C. William , Ivask Angela
Published: May 2018

Release of metal ions from metal-based surfaces has been considered one of the main drivers of their antimicrobial activity. Here we describe a method that enables parallel assessment of metal ion release from solid metallic surfaces and antimicrobial efficacy of these surfaces in a short time period. The protocol involves placement of a small volume of bioluminescent bacteria onto the tested surface and direct measurement of bioluminescence at various time points. In this study, two recombinant Escherichia coli strains, one expressing bioluminescence constitutively and applicable for general antimicrobial testing, and the other induced by Cu ions, were selected. Decrease in bioluminescence of constitutive E. coli on the surfaces showed a good correlation with the decrease in bacterial viability. Response of Cu-inducible E. coli showed a correlation with Cu content in the tested surfaces but not with Cu dissolution suggesting the role of direct bacteria-surface contact in Cu ion-driven antibacterial effects. In summary, the presented protocol enables the analysis of microbial toxicity and bioavailability of surface-released metal ions directly on solid surfaces within 30–60 min. Although optimized for copper and copper alloy surfaces and E. coli, the method can be extended to other types of metallic surfaces and bacterial strains.
One-way edge modes in a photonic crystal of semiconductor at terahertz frequencies
Authors: He Lingjuan , Shen Qian , Xu Jie , You Yun , Yu Tianbao , Shen Linfang , Deng Xiaohua
Published: May 2018

Electromagnetic edge mode in a photonic crystal (PhC), which is a square array of semiconductor rods in air, is theoretically investigated for terahertz frequencies. In the PhC, gyroelectric anisotropy is introduced in the semiconductor rods by applying an external magnetic field and consequently, a degeneracy point, at which two dispersion surfaces intersect, is lifted and a new band gap is created. The edge mode sustained by the PhC possesses the character of one-way propagation, and it even can be immune to backscattering at large defect on the wavelength scale and 90° sharp bend. The properties of the one-way mode are closely dependent on the cladding layer structure of the PhC.
The neurotrophic tyrosine kinase receptor TrkA and its ligand NGF are increased in squamous cell carcinomas of the lung
Authors: Gao Fangfang , Griffin Nathan , Faulkner Sam , Rowe Christopher W. , Williams Lily , Roselli Severine , Thorne Rick F. , Ferdoushi Aysha , Jobling Phillip , Walker Marjorie M. , Hondermarck Hubert
Published: May 2018

The neurotrophic tyrosine kinase receptor TrkA (NTRK1) and its ligand nerve growth factor (NGF) are emerging promoters of tumor progression. In lung cancer, drugs targeting TrkA are in clinical trials, but the clinicopathological significance of TrkA and NGF, as well as that of the precursor proNGF, the neurotrophin co-receptor p75NTR and the proneurotrophin co-receptor sortilin, remains unclear. In the present study, analysis of these proteins was conducted by immunohistochemistry and digital quantification in a series of 204 lung cancers of different histological subtypes versus 121 normal lung tissues. TrkA immunoreactivity was increased in squamous cell carcinoma compared with benign and other malignant lung cancer histological subtypes (p < 0.0001). NGF and proNGF were also increased in squamous cell carcinoma, as well as in adenocarcinoma (p < 0.0001). In contrast, p75NTR was increased across all lung cancer histological subtypes compared to normal lung (p < 0.0001). Sortilin was higher in adenocarcinoma and small cell carcinoma (p < 0.0001). Nerves in the tumor microenvironment were negative for TrkA, NGF, proNGF, p75NTR and sortilin. In conclusion, these data suggest a preferential therapeutic value of targeting the NGF-TrkA axis in squamous cell carcinomas of the lung.
High-throughput screening identified selective inhibitors of exosome biogenesis and secretion: A drug repurposing strategy for advanced cancer
Authors: Datta Amrita , Kim Hogyoung , McGee Lauren , Johnson Adedoyin E. , Talwar Sudha , Marugan Juan , Southall Noel , Hu Xin , Lal Madhu , Mondal Debasis , Ferrer Marc , Abdel-Mageed Asim B.
Published: May 2018

Targeting exosome biogenesis and release may have potential clinical implications for cancer therapy. Herein, we have optimized a quantitative high throughput screen (qHTS) assay to identify compounds that modulate exosome biogenesis and/or release by aggressive prostate cancer (PCa) CD63-GFP-expressing C4-2B cells. A total of 4,580 compounds were screened from the LOPAC library (a collection of 1,280 pharmacologically active compounds) and the NPC library (NCGC collection of 3,300 compounds approved for clinical use). Twenty-two compounds were found to be either potent activators or inhibitors of intracellular GFP signal in the CD63-GFP-expressing C4-2B cells. The activity of lead compounds in modulating the secretion of exosomes was validated by a tunable resistive pulse sensing (TRPS) system (qNano-IZON) and flow cytometry. The mechanism of action of the lead compounds in modulating exosome biogenesis and/or secretion were delineated by immunoblot analysis of protein markers of the endosomal sorting complex required for transport (ESCRT)-dependent and ESCRT-independent pathways. The lead compounds tipifarnib, neticonazole, climbazole, ketoconazole, and triademenol were validated as potent inhibitors and sitafloxacin, forskolin, SB218795, fenoterol, nitrefazole and pentetrazol as activators of exosome biogenesis and/or secretion in PC cells. Our findings implicate the potential utility of drug-repurposing as novel adjunct therapeutic strategies in advanced cancer.
Multiple implications of an active site phenylalanine in the catalysis of aryl-alcohol oxidase
Authors: Carro Juan , Amengual-Rigo Pep , Sancho Ferran , Medina Milagros , Guallar Victor , Ferreira Patricia , Martínez Angel T.
Published: May 2018

Aryl-alcohol oxidase (AAO) has demonstrated to be an enzyme with a bright future ahead due to its biotechnological potential in deracemisation of chiral compounds, production of bioplastic precursors and other reactions of interest. Expanding our understanding on the AAO reaction mechanisms, through the investigation of its structure-function relationships, is crucial for its exploitation as an industrial biocatalyst. In this regard, previous computational studies suggested an active role for AAO Phe397 at the active-site entrance. This residue is located in a loop that partially covers the access to the cofactor forming a bottleneck together with two other aromatic residues. Kinetic and affinity spectroscopic studies, complemented with computational simulations using the recently developed adaptive-PELE technology, reveal that the Phe397 residue is important for product release and to help the substrates attain a catalytically relevant position within the active-site cavity. Moreover, removal of aromaticity at the 397 position impairs the oxygen-reduction activity of the enzyme. Experimental and computational findings agree very well in the timing of product release from AAO, and the simulations help to understand the experimental results. This highlights the potential of adaptive-PELE to provide answers to the questions raised by the empirical results in the study of enzyme mechanisms.
Dissecting Clinical and Metabolomics Associations of Left Atrial Phasic Function by Cardiac Magnetic Resonance Feature Tracking
Authors: Koh Angela S. , Gao Fei , Leng Shuang , Kovalik Jean-Paul , Zhao Xiaodan , Tan Ru San , Fridianto Kevin Timothy , Ching Jianhong , Chua Serene JM , Yuan Jian-Min , Koh Woon-Puay , Zhong Liang
Published: May 2018

Among community cohorts, associations between clinical and metabolite factors and complex left atrial (LA) phasic function assessed by cardiac magnetic resonance (CMR) feature tracking (FT) are unknown. Longitudinal LA strain comprising reservoir strain (εs), conduit strain (εe) and booster strain (εa) and their corresponding peak strain rates (SRs, SRe, SRa) were measured using CMR FT. Targeted mass spectrometry measured 83 circulating metabolites in serum. Sparse Principal Component Analysis was used for data reduction. Among community adults (n = 128, 41% female) (mean age: 70.5 ± 11.6 years), age was significantly associated with εs (β = −0.30, p < 0.0001), εe (β = −0.3, p < 0.0001), SRs (β = −0.02, p < 0.0001), SRe (β = 0.04, p < 0.0001) and SRe/SRa (β = −0.01, p = 0.012). In contrast, heart rate was significantly associated with εa (β = 0.1, p = 0.001) and SRa (β = −0.02, p < 0.0001). Serine was significantly associated with εs (β = 10.1, p = 0.015), SRs (β = 0.5, p = 0.033) and SRa (β = −0.9, p = 0.016). Citrulline was associated with εs (β = −4.0, p = 0.016), εa (β = −3.4, p = 0.002) and SRa (β = 0.4, p = 0.019). Valine was associated with ratio of SRe:SRa (β = −0.4, p = 0.039). Medium and long chain dicarboxyl carnitines were associated with εs (β = −0.6, p = 0.038). Phases of LA function were differentially associated with clinical and metabolite factors. Metabolite signals may be used to advance mechanistic understanding of LA disease in future studies.
Network-guided genomic and metagenomic analysis of the faecal microbiota of the critically endangered kakapo
Authors: Waite David W. , Dsouza Melissa , Sekiguchi Yuji , Hugenholtz Philip , Taylor Michael W.
Published: May 2018

The kakapo is a critically endangered, herbivorous parrot endemic to New Zealand. The kakapo hindgut hosts a dense microbial community of low taxonomic diversity, typically dominated by Escherichia fergusonii, and has proven to be a remarkably stable ecosystem, displaying little variation in core membership over years of study. To elucidate mechanisms underlying this robustness, we performed 16S rRNA gene-based co-occurrence network analysis to identify potential interactions between E. fergusonii and the wider bacterial community. Genomic and metagenomic sequencing were employed to facilitate interpretation of potential interactions observed in the network. E. fergusonii maintained very few correlations with other members of the microbiota, and isolates possessed genes for the generation of energy from a wide range of carbohydrate sources, including plant fibres such as cellulose. We surmise that this dominant microorganism is abundant not due to ecological interaction with other members of the microbiota, but its ability to metabolise a wide range of nutrients in the gut. This research represents the first concerted effort to understand the functional roles of the kakapo microbiota, and leverages metagenomic data to contextualise co-occurrence patterns. By combining these two techniques we provide a means for studying the diversity-stability hypothesis in the context of bacterial ecosystems.
Long-Term Administration of Conjugated Estrogen and Bazedoxifene Decreased Murine Fecal β-Glucuronidase Activity Without Impacting Overall Microbiome Community
Authors: Chen Karen Lee Ann , Liu Xiaoji , Zhao Yiru Chen , Hieronymi Kadriye , Rossi Gianluigi , Auvil Loretta Sue , Welge Michael , Bushell Colleen , Smith Rebecca Lee , Carlson Kathryn E. , Kim Sung Hoon , Katzenellenbogen John A. , Miller Michael Joseph , Madak-Erdogan Zeynep
Published: May 2018

Conjugated estrogens (CE) and Bazedoxifene (BZA) combination is used to alleviate menopause-associated symptoms in women. CE+BZA undergo first-pass-metabolism in the liver and deconjugation by gut microbiome via β-glucuronidase (GUS) enzyme inside the distal gut. To date, the impact of long-term exposure to CE+BZA on the gut microbiome or GUS activity has not been examined. Our study using an ovariectomized mouse model showed that CE+BZA administration did not affect the overall cecal or fecal microbiome community except that it decreased the abundance ofAkkermansia, which was identified as a fecal biomarker correlated with weight gain. The fecal GUS activity was reduced significantly and was positively correlated with the abundance of Lactobacillaceae in the fecal microbiome. We further confirmed inEscherichia coliK12 andLactobacillus gasseriADH that Tamoxifen-, 4-hydroxy-Tamoxifen- and Estradiol-Glucuronides competed for GUS activity. Our study for the first time demonstrated that long-term estrogen supplementation directly modulated gut microbial GUS activity. Our findings implicate that long-term estrogen supplementation impacts composition of gut microbiota and microbial activity, which affects estrogen metabolism in the gut. Thus, it is possible to manipulate such activity to improve the efficacy and safety of long-term administered estrogens for postmenopausal women or breast cancer patients.
Multiple Reaction Monitoring for quantitative laccase kinetics by LC-MS
Authors: Perna Valentina , Agger Jane W. , Holck Jesper , Meyer Anne S.
Published: May 2018

Laccases (EC 1.10.3.2) are enzymes known for their ability to catalyse the oxidation of phenolic compounds using molecular oxygen as the final electron acceptor. Lignin is a natural phenylpropanoids biopolymer whose degradation in nature is thought to be aided by enzymatic oxidation by laccases. Laccase activity is often measured spectrophotometrically on compounds such as syringaldazine and ABTS which poorly relate to lignin. We employed natural phenolic hydroxycinnamates having different degree of methoxylations, p-coumaric, ferulic and sinapic acid, and a lignin model OH-dilignol compound as substrates to assess enzyme kinetics by HPLC-MS on two fungal laccases Trametes versicolor laccase, Tv and Ganoderma lucidum laccase, Gl. The method allowed accurate kinetic measurements and detailed insight into the product profiles of both laccases. Both Tv and Gl laccase are active on the hydroxycinnammates and show a preference for substrate with methoxylations. Product profiles were dominated by the presence of dimeric and trimeric species already after 10 minutes of reaction and similar profiles were obtained with the two laccases. This new HPLC-MS method is highly suitable and accurate as a new method for assaying laccase activity on genuine phenolic substrates, as well as a tool for examining laccase oxidation product profiles.
Effects of Low-level Brodifacoum Exposure on the Feline Immune Response
Authors: Kopanke Jennifer H. , Horak Katherine E. , Musselman Esther , Miller Craig A. , Bennett Kristine , Olver Christine S. , Volker Steven F. , VandeWoude Sue , Bevins Sarah N.
Published: May 2018

Anticoagulant rodenticides have been implicated as a potential inciting factor in the development of mange in wild felids, but a causative association between anticoagulant rodenticide exposure and immune suppression has not been established. Specific-pathogen-free domestic cats were exposed to brodifacoum over a 6-week period to determine whether chronic, low-level exposure altered the feline immune response. Cats were vaccinated with irrelevant antigens at different points during the course of the experiment to assess recall and direct immune responses. Measures of immune response included delayed-type hypersensitivity tests and cell proliferation assays. IgE and antigen-specific antibodies were quantified via ELISA assays, and cytokine induction following exposure to vaccine antigens was also analyzed. While cats had marked levels of brodifacoum present in blood during the study, no cats developed coagulopathies or hematologic abnormalities. Brodifacoum-exposed cats had transient, statistically significant decreases in the production of certain cytokines, but all other measures of immune function remained unaffected throughout the study period. This study indicates that cats may be more resistant to clinical effects of brodifacoum exposure than other species and suggests that the gross impacts of environmentally realistic brodifacoum exposure on humoral and cell-mediated immunity against foreign antigen exposures in domestic cats are minimal.
An individual differences approach to semantic cognition: Divergent effects of age on representation, retrieval and selection
Authors: Hoffman Paul
Published: May 2018

Semantic cognition refers to the appropriate use of acquired knowledge about the world. This requires representation of knowledge as well as control processes which ensure that currently-relevant aspects of knowledge are retrieved and selected. Although these abilities can be impaired selectively following brain damage, the relationship between them in healthy individuals is unclear. It is also commonly assumed that semantic cognition is preserved in later life, because older people have greater reserves of knowledge. However, this claim overlooks the possibility of decline in semantic control processes. Here, semantic cognition was assessed in 100 young and older adults. Despite having a broader knowledge base, older people showed specific impairments in semantic control, performing more poorly than young people when selecting among competing semantic representations. Conversely, they showed preserved controlled retrieval of less salient information from the semantic store. Breadth of semantic knowledge was positively correlated with controlled retrieval but was unrelated to semantic selection ability, which was instead correlated with non-semantic executive function. These findings indicate that three distinct elements contribute to semantic cognition: semantic representations that accumulate throughout the lifespan, processes for controlled retrieval of less salient semantic information, which appear age-invariant, and mechanisms for selecting task-relevant aspects of semantic knowledge, which decline with age and may relate more closely to domain-general executive control.
The conserved RNA recognition motif and C3H1 domain of the Not4 ubiquitin ligase regulate in vivo ligase function
Authors: Chen Hongfeng , Sirupangi Tirupataiah , Wu Zhao-Hui , Johnson Daniel L. , Laribee R. Nicholas
Published: May 2018

The Ccr4-Not complex controls RNA polymerase II (Pol II) dependent gene expression and proteasome function. The Not4 ubiquitin ligase is a Ccr4-Not subunit that has both a RING domain and a conserved RNA recognition motif and C3H1 domain (referred to as the RRM-C domain) with unknown function. We demonstrate that while individual Not4 RING or RRM-C mutants fail to replicate the proteasomal defects found in Not4 deficient cells, mutation of both exhibits a Not4 loss of function phenotype. Transcriptome analysis revealed that the Not4 RRM-C affects a specific subset of Pol II-regulated genes, including those involved in transcription elongation, cyclin-dependent kinase regulated nutrient responses, and ribosomal biogenesis. The Not4 RING, RRM-C, or RING/RRM-C mutations cause a generalized increase in Pol II binding at a subset of these genes, yet their impact on gene expression does not always correlate with Pol II recruitment which suggests Not4 regulates their expression through additional mechanisms. Intriguingly, we find that while the Not4 RRM-C is dispensable for Ccr4-Not association with RNA Pol II, the Not4 RING domain is required for these interactions. Collectively, these data elucidate previously unknown roles for the conserved Not4 RRM-C and RING domains in regulating Ccr4-Not dependent functionsin vivo.
RNA synthesis is modulated by G-quadruplex formation in Hepatitis C virus negative RNA strand
Authors: Jaubert Chloé , Bedrat Amina , Bartolucci Laura , Di Primo Carmelo , Ventura Michel , Mergny Jean-Louis , Amrane Samir , Andreola Marie-Line
Published: May 2018

DNA and RNA guanine-rich oligonucleotides can form non-canonical structures called G-quadruplexes or “G4” that are based on the stacking of G-quartets. The role of DNA and RNA G4 is documented in eukaryotic cells and in pathogens such as viruses. Yet, G4 have been identified only in a few RNA viruses, including the Flaviviridae family. In this study, we analysed the last 157 nucleotides at the 3′end of the HCV (−) strand. This sequence is known to be the minimal sequence required for an efficient RNA replication. Using bioinformatics and biophysics, we identified a highly conserved G4-prone sequence located in the stem-loop IIy’ of the negative strand. We also showed that the formation of this G-quadruplex inhibits the in vitro RNA synthesis by the RdRp. Furthermore, Phen-DC3, a specific G-quadruplex binder, is able to inhibit HCV viral replication in cells in conditions where no cytotoxicity was measured. Considering that this domain of the negative RNA strand is well conserved among HCV genotypes, G4 ligands could be of interest for new antiviral therapies.
Exploring a possible connection between U.S. tornado activity and Arctic sea ice
Authors: Trapp Robert J. , Hoogewind Kimberly A.
Published: May 2018

The significant losses in Arctic sea ice over the past few decades appear to have been accompanied by changes in global-scale and regional-scale atmospheric circulation. Such circulation changes have in turn been used to support arguments that low Arctic sea-ice extent (SIE) has helped to promote extreme weather events within the mid-latitudes. The contemporaneous variability in U.S. tornado incidence over the past decade provides motivation to explore whether the essence of these arguments also applies to tornadoes. Here, robust statistical correlations are found between tornado activity and SIE during boreal summer, specifically in July. The statistical relationship is supported by the presence of anomalous regional circulation and storm track that are unfavorable (favorable) for tornado-bearing thunderstorm formation when SIE is low (high).
Room-temperature synthesis of χ-Al2O3 and ruby (α-Cr:Al2O3)
Authors: Cortes-Vega Fernando D. , Yang Wenli , Zarate-Medina J. , Brankovic Stanko R. , Herrera Ramírez José M. , Robles Hernandez Francisco C.
Published: May 2018

In this work, we present a unique crystal growth synthesis of χ-Al2O3 accompanied with α-Cr:Al2O3 at room temperature.
Increase of Cr solubility in cubic Sr2FexCr2−xO6−y unit cell using sol–gel assisted synthesis and characterizations of Sr2FeCrO6−y phase
Authors: Song G. , Bovo L. , Terry L. R. , Gómez Rojas O. , Hall S. R.
Published: May 2018

A homogeneous, non-selective chelating system using EDTA–chitosan was created to produce a cubic phase perovskite material Sr2FeCrO6−y.
Correction: Insights into the enhanced CeN triple bond in the HCeN molecule
Authors: Pu Zhen , Yu Wenjie , Roy Soumendra K. , Li Chaoyang , Ao Bingyun , Liu Tianwei , Shuai Maobing , Wang Xuefeng
Published: May 2018

Correction for ‘Insights into the enhanced CeN triple bond in the HCeN molecule’ by Zhen Pu et al., Phys. Chem. Chem. Phys., 2017, 19, 8216–8222.
Elucidating the reactivity of methoxyphenol positional isomers towards hydrogen-transfer reactions by ATR-IR spectroscopy of the liquid–solid interface of RANEY® Ni
Authors: de Castro Ilton Barros Daltro , Graça Inês , Rodríguez-García Laura , Kennema Marco , Rinaldi Roberto , Meemken Fabian
Published: May 2018

In the presence of Raney® Ni and 2-propanol, guaiacol is orientated parallel to the catalyst surface, whereas 3- and 4-methoxyphenol forms a titled adsorption surface complex.
Long-term exposure to silver nanoparticles affects periphyton community structure and function
Authors: Gil-Allué Carmen , Tlili Ahmed , Schirmer Kristin , Gessner Mark O. , Behra Renata
Published: May 2018

Silver nanoparticles (AgNPs) are widely used as antimicrobial agents.
Elaboration of a chemical sensor based on polyaniline and sulfanilic acid diazonium salt for highly sensitive detection nitrite ions in acidified aqueous media
Authors: Diarisso Abdoulaye , Fall Modou , Raouafi Noureddine
Published: May 2018

The work describes the use of sulfonic acid-functionalized GCE as a scaffold to build a highly sensitive PANI-based sensor for nitrite ions in aqueous medium.
Oleuropein and hydroxytyrosol rich extracts from olive leaves attenuate liver injury and lipid metabolism disturbance in bisphenol A-treated rats
Authors: Mahmoudi Asma , Hadrich Fatma , Feki Ines , Ghorbel Hela , Bouallagui Zouhaier , Marrekchi Rim , Fourati Hela , Sayadi Sami
Published: May 2018

OLE and HYT olive leaves rich extracts possess hypolipidemic and hepatoprotective effects against BPA-induced metabolic disorders by enhancing the antioxidative defense system and regulation of important signaling pathway activities.
Partner-facilitating transmembrane penetration of nanoparticles: a biological test in silico
Authors: Wang W , Yang R , Zhang F , Yuan B , Yang K , Ma Y
Published: May 2018

Introducing a partner nanoparticle (NP) facilitates transmembrane penetration of a host NP due to membrane-mediated cooperation between them.
Gold- and silver-catalyzed intramolecular annulation and rearrangement of aniline-linked 1,6-enynes containing methylenecyclopropanes
Authors: Jiang Bo , Wei Yin , Shi Min
Published: May 2018

A new synthetic approach for the construction of 1,2-dihydroquinolines having a methylenecyclopropane moiety or a cyclobutene moiety has been developed from gold- and silver-catalyzed annulation of N-tethered 1,6-enynes containing methylenecyclopropanes.
Studies on metal charge density and band gap characteristics produced by the (nBuCp)2ZrCl2 compound and its reaction mechanism
Authors: Wang Hai , Zhang Peng , Zhou Panpan , Xu Renwei , Tang Yu
Published: May 2018

The charge density of the central metal atoms and band gap of the compounds were investigated by the Dmol3 software package in Density functional theory (DFT).
Decoration of metal oxide surface with {111} form Au nanoparticles using PEGylation
Authors: Moon Cheon Woo , Park Jongseong , Hong Seung-Pyo , Sohn Woonbae , Andoshe Dinsefa Mensur , Shokouhimehr Mohammadreza , Jang Ho Won
Published: May 2018

Phase transfer in the ethanol-dichloromethane medium extinguished the limitation of the ligand exchange reaction on the gold (111) surface. High-coverage octahedral Au NP decoration on metal oxide semiconductors is achieved by the process.
Correction: A long-persistent phosphorescent chemosensor for the detection of TNP based on CaTiO3:Pr3+@SiO2 photoluminescence materials
Authors: Li Fangfang , Wang Fengyi , Hu Xuan , Zheng Baozhan , Du Juan , Xiao Dan
Published: May 2018

Correction for ‘A long-persistent phosphorescent chemosensor for the detection of TNP based on CaTiO3:Pr3+@SiO2 photoluminescence materials’ by Fangfang Li et al., RSC Adv., 2018, 8, 16603–16610.
Thermodynamic versus kinetic control in substituent redistribution reactions of silylium ions steered by the counteranion
Authors: Omann Lukas , Pudasaini Bimal , Irran Elisabeth , Klare Hendrik F. T. , Baik Mu-Hyun , Oestreich Martin
Published: May 2018

Substituent exchange reactions of silylium ions can be steered in opposite directions. The judicious choice of the hydrosilane and the counteranion enables the selective formation of either triaryl- or trialkylsilylium ions.
White-light emission from a single organic compound with unique self-folded conformation and multistimuli responsiveness
Authors: Li Dengfeng , Hu Wende , Wang Jie , Zhang Qiwei , Cao Xiao-Ming , Ma Xiang , Tian He
Published: May 2018

White-light emission from a single molecule was realized and tuned via multistimuli including excitation, solvent polarity, temperature and host–guest interactions.
An option for stranded renewables: electrolytic-hydrogen in future energy systems
Authors: Grube Thomas , Doré Larissa , Hoffrichter André , Hombach Laura Elisabeth , Raths Stephan , Robinius Martin , Nobis Moritz , Schiebahn Sebastian , Tietze Vanessa , Schnettler Armin , Walther Grit , Stolten Detlef
Published: May 2018

Our study integrates power sector modelling with hydrogen infrastructure analysis and life cycle assessment complementing research on power-to-gas pathway alternatives.
Disordered carbon tubes based on cotton cloth for modulating interface impedance in β′′-Al2O3-based solid-state sodium metal batteries
Authors: Wu Tian , Wen Zhaoyin , Sun Changzhi , Wu Xiangwei , Zhang Sanpei , Yang Jianhua
Published: May 2018

Disordered carbon tubes for modulating the interface impedance in β′′-Al2O3-based solid-state sodium metal batteries.
Ternary non-fullerene polymer solar cells with an efficiency of 11.6% by simultaneously optimizing photon harvesting and phase separation
Authors: Wang Jianxiao , Gao Wei , An Qiaoshi , Zhang Miao , Ma Xiaoling , Hu Zhenghao , Zhang Jian , Yang Chuluo , Zhang Fujun
Published: May 2018

A PCE of 11.6% is achieved in ternary PSCs by optimizing photon harvesting and phase separation of active layers.
Regulation of radicals from electrochemical exfoliation of a double-graphite electrode to fabricate high-quality graphene
Authors: Li Le , Wang Minqiang , Guo Jun , Cao Minghui , Qiu Hengwei , Dai Liyan , Yang Zhi
Published: May 2018

Adjusting oxygen free radicals exfoliated from double graphite electrodes by adding thiourea and lowering the temperature to prepare high quality graphene.
Recent progress in the mechanofluorochromism of cyanoethylene derivatives with aggregation-induced emission
Authors: Zhao Juan , Chi Zhihe , Zhang Yi , Mao Zhu , Yang Zhiyong , Ubba Eethamukkala , Chi Zhenguo
Published: May 2018

This review provides a clear overview of the recent progress in the mechanofluorochromism of cyanoethylene derivatives with aggregation-induced emission.
15-GHz radio emission from nearby low-luminosity active galactic nuclei
Authors: Saikia Payaswini , Körding Elmar , Coppejans Deanne L. , Falcke Heino , Williams David , Baldi Ranieri D. , Mchardy Ian , Beswick Rob
Published: May 2018

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been detected above a flux density of 40 μ Jy in 60% (45 of 76) of the LLAGN sample. We detect 20 out of 31 (64%) low-ionization nuclear emission-line region (LINER) nuclei, ten out of 14 (71%) low-luminosity Seyfert galaxies, and 15 out of 31 (48%) transition objects. We use this sample to explore correlations between different emission lines and the radio luminosity. We also populate the X-ray and the optical fundamental plane of black hole activity and further refine its parameters. We obtain a fundamental plane relation of log LR = 0.48 (±0.04) log LX + 0.79 (±0.03) log M and an optical fundamental plane relation of log LR = 0.63 (±0.05) log L[O III] + 0.67 (±0.03) log M after including all the LLAGN detected at high resolution at 15 GHz, and the best-studied hard-state X-ray binaries (luminosities are given in erg s−1 while the masses are in units of solar mass). Finally, we find conclusive evidence that the nuclear 15 GHz radio luminosity function (RLF) of all the detected Palomar Sample LLAGN has a turnover at the low-luminosity end, and is best-fitted with a broken power law. The break in the power law occurs at a critical mass accretion rate of 1.2 × 10−3 M⊙ yr−1, which translates to an Eddington ratio of ṁEdd ~ 5.1 × 10−5, assuming a black hole mass of 109 M⊙. The local group stands closer to the extrapolation of the higher-luminosity sources, and the classical Seyferts agree with the nuclear RLF of the LLAGN in the local universe.
Control problem on space of random variables and master equation
Authors: Bensoussan Alain , Yam Sheung Chi Phillip
Published: May 2018

In this article, we study a control problem in an appropriate space of random variables; in fact, in our set up, we can consider an arbitrary Hilbert space, yet we specialize only to a Hilbert space of square-integrable random variables. We see that the control problem can then be related to a mean field type control problem. We explore here a suggestion of Lions in (Lectures at College de France, http://www.college-de-france.fr) and (Seminar at College de France). Mean field type control problems are control problems in which functionals depend on probability measures of the underlying controlled process. Gangbo and Święch [J. Differ. Equ. 259 (2015) 6573–6643] considered this type of problem in the space of probability measures equipped with the Wasserstein metric and use the concept of Wasserstein gradient; their work provides a completely rigorous treatment, but it is quite intricate, because metric spaces are not vector spaces. The approach suggested by Lions overcomes this difficulty. Nevertheless, our present proposed approach also benefits from the useful concept of L-derivatives as introduced in a recent interesting treatise of Carmona and Delarue [Probabilistic Theory of Mean Field Games with Applications. Springer Verlag (2017)]. We also consider Bellman equation and the Master equation of mean field type control. We provide also some extension of the results of Gangbo and Święch [J. Differ. Equ. 259 (2015) 6573–6643].