bluuebunny/crossref_metadata_2025 huggingface dataset:
Addition of Daptomycin to Levofloxacin Increased the Efficacy of Levofloxacin Monotherapy against a Methicillin-SusceptibleStaphylococcus aureusStrain in Experimental Meningitis and Prevented Development of Resistance
Authors: Cottagnoud Philippe , Sprenker Frederike , Cottagnoud Marianne , Collaud Alexandra , Ashkbus Reza , Perreten Vincent
Published: October 2020

Daptomycin and levofloxacin were tested as monotherapies and in combination against the antibiotic-susceptibleS. aureusstrain MSSA 1112 in a rabbit meningitis model and the effect of the combination on induction of resistance was determined in vitro. Changes of the susceptibility to fluoroquinolones and daptomycin was determined by the measurement of the MIC and mutations were detected by whole genome sequence comparison of the mutants with the parent strain MSSA 1112. Meningitis was induced by intracisternal inoculation of 105CFU of MSSA 1112 and treatment was started 10 h later by injection of daptomycin (15 mg/kg) and levofloxacin (10 mg/kg) standard doses. Cerebrospinal fluid (CSF) samples were repeatedly collected during therapy in order to determine killing rates and results of bactericidal activity were expressed in Δlog10CFU/ml over 8 h. The combination of daptomycin with levofloxacin was significantly (p< 0.001) superior to levofloxacin monotherapy and increased the antibacterial activity of daptomycin. In vitro, MSSA 1112 was cycled over six days with either increasing concentrations of levofloxacin or daptomycin or with a combination of levofloxacin with half of the MIC of daptomycin or daptomycin with half of the MIC of levofloxacin leading to mutations in target genes as identified by whole genome sequence analysis. Addition of low concentration of daptomycin (0.25 mg/L) reduced levofloxacin-induced resistance in vitro. Addition of levofloxacin in low concentration (0.125 mg/L) did not influence daptomycin-induced resistance.

These findings highlight the lack of reciprocal interference of antibiotics in combination with regard to the development of resistance.
Projecting the impact of behaviour and isolation interventions and super spreader events from mass gatherings and international travel on Malaysia’s COVID-19 epidemic trajectories using an augmented SEIR model
Authors: Ayub Aidonna Jan , Wai Son Gregory Ho , Hanafiah Khayriyyah Mohd
Published: October 2020

Background

Various levels of lockdown implemented to contain the rapid spread of COVID-19 are not long-term solutions due to socioeconomic implications.

Methods

To inform safe reopening, we used an augmented SEIR model to project the impact of 1) interventions and potential new epidemic trajectories arising from super spreader (SS) events and/or international travel and 2) re-introducing strong behavioural interventions on resurgence trajectories.

Results

Our model suggests that 50% behaviour intervention effectiveness (BIE) (from enforced social distancing during lockdown, early in the epidemic), along with 50% isolation intervention effectiveness (IIE) (from increased testing and isolating infected individuals) was achieved during lockdown, which curbed COVID-19 transmission in Malaysia. Post-lockdown, BIE plays a minimal role if IIE reaches or exceeds 46.9% when other variables are held constant. At IIE of 30% and BIE of 21.3%, SS events of 5,000 active cases risks COVID-19 resurgence, with 4-year projected 12.9mn cumulative cases and 1.1mn deaths. Earlier action to increase BIE to 50% on day 98 compared to day 111, prevented an additional 21,401 recovered cases and 257 deaths.

Conclusion

Until a safe and effective vaccine is widely available, the risk of COVID-19 resurgence from large SS events warrants caution in decisions to allow for mass gatherings and regular international travel.
Repulsive electrostatic interactions modulate dense and dilute phase properties of biomolecular condensates
Authors: Crabtree Michael D. , Holland Jack , Kompella Purnima , Babl Leon , Turner Noah , Baldwin Andrew J. , Nott Timothy J.
Published: October 2020

Liquid-like membraneless organelles form via multiple, weak interactions between biomolecules. The resulting condensed states constitute novel solvent environments inside eukaryotic cells that partition biomolecules and may favour particular biochemical reactions. Here we demonstrate that, in addition to attractive interactions, repulsive electrostatic interactions modulate condensate properties. We find that net charge modulates the formation, morphology and solvent properties of model Ddx4 condensates in cells and in vitro and that a net negative charge is conserved across germ cell-specific Ddx4 orthologues. This conserved net charge provides a sensitivity to multivalent cations that is not observed in somatic paralogues. The disfavouring effect of a net negative charge in Ddx4 orthologues appears to be offset by increased charge patterning, indicating that fine tuning of both attractive and repulsive interactions can create responsive solvent environments inside biomolecular condensates.
Separable neural mechanisms support intentional forgetting and thought substitution
Authors: Hubbard Ryan J. , Sahakyan Lili
Published: October 2020

Psychological and neuroscientific experiments have established that people can intentionally forget information via different strategies: direct suppression and thought substitution. However, few studies have directly compared the effectiveness of these strategies in forgetting specific items, and it remains an open question if the neural mechanisms supporting these strategies differ. Here, we developed a novel item-method directed forgetting paradigm with Remember, Forget, and Imagine cues, and recorded EEG to directly compare these strategies. Behaviorally, Forget and Imagine cues produced similar forgetting compared to Remember cues, but through separable neural processes; Forget cues elicited frontal oscillatory power changes that were predictive of future forgetting, whereas item-cue representational similarity was predictive of later accuracy for Imagine cues. These results suggest that both strategies can lead to intentional forgetting, but directed forgetting may rely on frontally-mediated suppression, while thought substitution may lead to contextual shifting, impairing successful retrieval.
Sexual selection theory meets disease vector control: Testing harmonic convergence as a “good genes” signal inAedes aegyptimosquitoes
Authors: League Garrett P. , Harrington Laura C. , Pitcher Sylvie A. , Geyer Julie K. , Baxter Lindsay L. , Montijo Julian , Rowland John G. , Johnson Lynn M. , Murdock Courtney C. , Cator Lauren J.
Published: October 2020

The mosquitoAedes aegyptiis a medically important, globally distributed vector of the viruses that cause dengue, yellow fever, chikungunya, and Zika. Although reproduction and mate choice are key components of vector population dynamics and control, our understanding of the mechanisms of sexual selection in mosquitoes remains poor. In “good genes” models of sexual selection, females use male cues as an indicator of both mate and offspring inherent genetic quality. Recent studies inAe. aegyptiprovide evidence that male wingbeat acoustics signal aspects of offspring quality and performance during mate selection in a process known as harmonic convergence. However, the extent to which harmonic convergence may signal overall inherent quality of mates and their offspring remains unknown. To examine this, we measured the potential acoustic signaling and heritability of a broad panel of parent and offspring fitness traits in two generations of field-derivedAe. aegyptioriginating from dengue endemic field sites in Thailand. Our data show that in this population of mosquitoes, harmonic convergence does not signal male fertility, female fecundity, and male flight performance traits, which despite displaying robust variability in both parents and their offspring were only weakly heritable. Together with previous work, our findings suggest that vector reproductive control programs should treat harmonic convergence as an indicator of some, but not all aspects of inherent quality, and that multiple forms of sexual selection are likely at play inAe. aegyptiin a trait, population, and environment dependent manner.
Oocyte Aging is Controlled by Mitogen Activated Protein Kinase Signaling
Authors: Achache Hanna , Falk Roni , Lerner Noam , Beatus Tsevi , Tzur Yonatan B.
Published: October 2020

Oogenesis is one of the first processes to fail during aging. In women, most oocytes cannot successfully complete meiotic divisions during the fourth decade of life. Studies of the nematodeCaenorhabditis eleganshave uncovered conserved genetic pathways that control lifespan, but our knowledge regarding reproductive aging in worms and humans is limited. Specifically, little is known about germline internal signals that dictate the oogonial biological clock. Here, we report a thorough characterization of the changes in the worm germline during aging. We found that shortly after ovulation halts, germline proliferation declines, while apoptosis continues, leading to a gradual reduction in germ-cell numbers. In late aging stages, we observed that meiotic progression is disturbed and crossover designation and DNA double-strand break repair decrease. In addition, we detected a decline in the quality of mature oocytes during aging, as reflected by decreasing size and elongation of interhomolog distance, a phenotype also observed in human oocytes. Many of these altered processes were previously attributed to MAPK signaling variations in young worms. In support of this, we observed changes in activation dynamics of MPK-1 during aging. We therefore tested the hypothesis that MAPK controls oocyte quality in aged worms using both genetic and pharmacological tools. We found that in mutants with high levels of activated MPK-1, oocyte quality deteriorates more rapidly than in wild-type worms, whereas reduction of MPK-1 levels enhances quality. Thus, our data indicate that MAPK signaling controls germline aging and could be used to attenuate the rate of oogenesis quality decline.
Midbrain dopaminergic inputs gate amygdala intercalated cell clusters by distinct and cooperative mechanisms
Authors: Aksoy-Aksel Ayla , Gall Andrea , Seewald Anna , Ferraguti Francesco , Ehrlich Ingrid
Published: October 2020

Abstract

Dopaminergic signaling plays an important role in associative learning including fear and extinction learning. Dopaminergic midbrain neurons encode prediction error-like signals when threats differ from expectations. Within the amygdala, GABAergic intercalated cell (ITC) clusters receive the densest dopaminergic projections, but their physiological consequences are incompletely understood. ITCs are important for fear extinction, a function thought to be supported by activation of ventromedial cluster ITCs that inhibit central amygdala fear output. In mice, we reveal two distinct mechanisms how mesencephalic dopaminergic afferents control ITCs. Firstly, they co-release GABA to mediate rapid, direct inhibition. Secondly, dopamine suppresses inhibitory interactions between distinct ITC clusters via presynaptic D1-receptors. Early extinction training augments both, GABA co-release onto dorso-medial ITCs and dopamine-mediated suppression of dorso- to ventromedial inhibition between ITC clusters. These findings provide novel insights into dopaminergic mechanisms shaping the activity balance between distinct ITC clusters that could support their opposing roles in fear behavior.
Phytochemical characterization andin vitroantibacterial activity ofXeroderris stuhlmannii(Taub.) Mendonca & E.P. Sousa bark extracts
Authors: Selemani Major A. , Kazingizi Luckmore F. , Manzombe Emily , Bishi Lorraine Y. , Mureya Cleopas , Gwata Tichaziwa T. , Rwere Freeborn
Published: October 2020

The use of herbal medicine is common in many rural communities in Zimbabwe because generic drugs are expensive and not readily available. In this work, we documented the important phytochemicals fromXeroderris stuhlmannii(Taub.) Mendonca & E.P. Sousa (Murumanyama in Shona), bark extracts and tested their antibacterial activity in order to demonstrate its potential as an antimicrobial agent. Qualitative screening of secondary metabolites confirmed the presence of alkaloids, flavonoids, terpenoids, steroids and polyphenols in the crude bark extracts. The MICs values for the crude extracts on six bacterial strains ranged from 0.23–0.80 mg/mL. Antimicrobial tests showed higher potency for crude bark extracts onE. Coli(MIC, 0.232 mg/mL) and lower potency oncoliform(MIC, 0.798 mg/mL). LC-MS/MS analysis of various fractions confirmed the presence of twenty-eight phytochemicals whereas, twelve phytochemicals were identified using GC-MS. Both techniques confirmed the presence of ursolic acid, roburic acid, reticuline, rotenone and p-coumaric acid glucoside in hexane and methanol extracts. In summary, our findings show thatXeroderris stuhlmannii(Taub.) Mendonca & E.P. Sousa contain many phytochemical compounds that have antimicrobial activity. Moreover, some of the compounds in the bark extract have been shown to possess antioxidant, antiviral, antitumor and anti-inflammatory properties. Thus,Xeroderris stuhlmannii(Taub.) Mendonca & E.P. Sousa barks can act as a useful herbal supplement for treatment of a number of diseases in rural communities where modern drugs are expensive and not readily available.
Evolutionary rescue in one dimensional stepping stone models
Authors: Tomasini Matteo , Peischl Stephan
Published: October 2020

Genetic variation and population sizes are critical factors for successful adaptation to novel environmental conditions. Gene flow between sub-populations is a potent mechanism to provide such variation and can hence facilitate adaptation, for instance by increasing genetic variation or via the introduction of beneficial variants. On the other hand, if gene flow between different habitats is too strong, locally beneficial alleles may not be able to establish permanently. In the context of evolutionary rescue, intermediate levels of gene flow are therefore often optimal for maximizing a species chance for survival in metapopulations without spatial structure. To which extent and under which conditions gene flow facilitates or hinders evolutionary rescue in spatially structured populations remains unresolved. We address this question by studying the differences between evolutionary rescue in the island model and in the stepping stone model in a gradually deteriorating habitat. We show that evolutionary rescue is modulated by the rate of gene flow between different habitats, which in turn depends strongly on the spatial structure and the pattern of environmental deterioration. We use these insights to show that in many cases spatially structured models can be translated into a simpler island model using an appropriately scaled effective migration rate.
Structure-based functional study of a peptide of an ecdysozoan superfamily: reveling a common molecular architecture and receptor-interacting residues
Authors: Chen Yun-Ru , Hsiao Nai-Wan , Huang Shiau-Shan , Chang Chih-Chun , Lee Yi-Zong , Tsai Jyuan-Ru , Lin Hui-Chen , Toullec Jean-Yves , Lee Chi-Ying , Lyu Ping-Chiang
Published: October 2020

A neuropeptide (Sco-CHH-L), belonging to the crustacean hyperglycemic hormone (CHH) superfamily and preferentially expressed in the pericardial organs (POs) of the mud crabScylla olivacea, was functionally and structurally studied. Its expression levels were significantly higher than the alternative splice form (Sco-CHH) in the POs and increased significantly after animals were subjected to a hypo-osmotic stress. Sco-CHH-L, but not Sco-CHH, significantly stimulatedin vitrothe Na+, K+-ATPase activity in the posterior (6th) gills. Furthermore, solution structure of Sco-CHH-L was resolved using nuclear magnetic resonance spectroscopy revealing that it has an N-terminal tail, three α-helices (α2, Gly9−Asn28; α3, His34−Gly38; α5, Glu62−Arg72), and a π-helix (π4, Cys43−Tyr53) and is structurally constrained by a pattern of disulfide bonds (Cys7-Cys43, Cys23-Cys39, Cys26-Cys52), which is characteristic of the CHH superfamily-peptides. Sco-CHH-L is topologically most similar to the molt-inhibiting hormone from the Kuruma prawnMarsupenaeus japonicuswith a backbone root-mean-square-deviation of 3.12 Å. Ten residues of Sco-CHH-L were chosen for alanine-substituted and the resulting mutants were functionally tested using the gill Na+, K+-ATPase activity assay, showing that the functionally important residues (I2, F3, E45, D69, I71, G73) are located at either end of the sequence, which are sterically close to each other and presumably constitutes the receptor binding sites. Sco-CHH-L was compared with other members of the superfamily revealing a molecular architecture, which is suggested to be common for the crustacean members of the superfamily, with the properties of the residues constituting the presumed receptor binding sites being the major factors dictating the ligand-receptor binding specificity.
A Library of Induced Pluripotent Stem Cells from Clinically Well-Characterized, Diverse Healthy Human Individuals
Authors: Schaniel Christoph , Dhanan Priyanka , Hu Bin , Xiong Yuguang , Raghunandan Teeya , Gonzalez David M. , Dariolli Rafael , D’Souza Sunita L. , Yadaw Arjun S. , Hansen Jens , Jayaraman Gomathi , Mathew Bino , Machado Moara , Berger Seth I. , Tripodi Joseph , Najfeld Vesna , Garg Jalaj , Miller Marc , Lynch Colleen S. , Michelis Katherine C. , Tangirala Neelima C. , Weerahandi Himali , Thomas David C. , Beaumont Kristin G. , Sebra Robert , Mahajan Milind , Schadt Eric , Vidovic Dusica , Schürer Stephan C. , Goldfarb Joseph , Azeloglu Evren U. , Birtwistle Marc R. , Sobie Eric A. , Kovacic Jason C. , Dubois Nicole C. , Iyengar Ravi
Published: October 2020

A library of well-characterized human induced pluripotent stem cell (hiPSC) lines from clinically healthy human subjects could serve as a useful resource of normal controls forin vitrohuman development, disease modeling, genotype-phenotype association studies, and drug response evaluation. We report generation and extensive characterization of a gender-balanced, racially/ethnically diverse library of hiPSC lines from 40 clinically healthy human individuals who range in age from 22-61. The hiPSCs match the karyotype and short tandem repeat identity of their parental fibroblasts, and have a transcription profile characteristic of pluripotent stem cells. We provide whole genome sequencing data for one hiPSC clone from each individual, genomic ancestry determination, and analysis of Mendelian disease genes and risks. We document similar transcriptomic profiles, single-cell RNA-seq derived cell clusters and physiology of cardiomyocytes differentiated from multiple independent hiPSC lines. This extensive characterization makes this hiPSC library a valuable resource for many studies on human biology.
Global diversity and biogeography of theZostera marinamycobiome
Authors: Ettinger Cassandra L. , Vann Laura E. , Eisen Jonathan A.
Published: October 2020

Seagrasses are marine flowering plants that provide critical ecosystem services in coastal environments worldwide. Marine fungi are often overlooked in microbiome and seagrass studies, despite terrestrial fungi having critical functional roles as decomposers, pathogens or endophytes in global ecosystems. Here we characterize the distribution of fungi associated with the seagrass,Zostera marina,using leaves, roots, and rhizosphere sediment from 16 locations across its full biogeographic range. Using high throughput sequencing of the ribosomal internal transcribed spacer (ITS) region and 18S ribosomal RNA gene, we first measured fungal community composition and diversity, then we tested hypotheses of neutral community assembly theory and the degree to which deviations suggested amplicon sequence variants (ASVs) were plant-selected or dispersal-limited, and finally we identified a core mycobiome and investigated the global distribution of differentially abundant ASVs. Our results show that the fungal community is significantly different between sites and follows a weak, but significant pattern of distance decay. Generally, there was evidence for both deterministic and stochastic factors contributing to community assembly of the mycobiome. TheZ. marinacore leaf and root mycobiomes are dominated by unclassified Sordariomycetes spp., unclassified Chytridiomycota lineages (including Lobulomycetaceae spp.), unclassified Capnodiales spp. andSaccharomycessp. A few ASVs (e.g.Lobulomycessp.) appear restricted to one or a handful of locations (e.g. possibly due to local adaptation, deterministic dispersal limitation or seasonal bloom events), while others (e.g.Saccharomycessp.) are more ubiquitous across all locations suggesting a true global distribution and possible plant-selection. Fungal guilds associated withZ. marinawere only weakly identified (10.12% of ITS region and 3.4% 18S rRNA gene ASV guild assignments were considered highly probable) including wood saprotrophs, ectomycorrhizal fungi, endophytic fungi and plant pathogens. Our results are similar to those found for other seagrass species. It is clear from the many unclassified fungal ASVs and fungal functional guilds, that our knowledge of marine fungi is still rudimentary. Further studies characterizing seagrass-associated fungi are needed to understand the roles of these microorganisms generally and when associated with seagrasses.
Two decades of creating drought tolerant maize and underpinning prediction technologies in the US corn-belt: Review and perspectives on the future of crop design
Authors: Messina Carlos D. , Cooper Mark , Hammer Graeme L. , Berning Dan , Ciampitti Ignacio , Clark Randy , Diepenbrock Christine , Gho Carla , Jines Mike , Lee Travis , McCormick Ryan , Mihura Eduardo , Podlich Dean , Rotundo Jose , Smalley Matt , Tang Tom , Truong Sandra , van Eeuwijk Fred
Published: October 2020

Over the last decade, society witnessed the largest expansion of agricultural land planted with drought tolerant (DT) maize (Zea maysL.) Dedicated efforts to drought breeding led to development of DT maize. Here we show that after two decades of sustained breeding efforts the rate of crop improvement under drought is in the range 1.0-1.6% yr−1, which is higher than rates (0.7% yr−1) reported prior to drought breeding. Prediction technologies that leverage biological understanding and statistical learning to improve upon the quantitative genetics framework will further accelerate genetic gain. A review of published and unpublished analyses conducted on data including 138 breeding populations and 93 environments between 2009 and 2019 demonstrated an average prediction skill (r) improvement around 0.2. These methods applied to pre-commercial stages showed accuracies higher that current statistical approaches (0.85 vs. 0.70). Improvement in hybrid and management choice can increase water productivity. Digital gap analyses are applicable at field scale suggesting the possibility of transition from evaluating hybrids to designing genotype x management (GxM) technologies for target cropping systems in drought prone areas. Due to the biocomplexity of drought, research and development efforts should be sustained to advance knowledge and iteratively improve models.

Highlight

Crop improvement rate in maize increased after implementation of drought breeding efforts. Harnessing crop, quantitative genetics and gap models will enable the transition from genetic evaluation to crop design.
Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family
Authors: Jäger Franziska , Lamy Anaïs , Guerini Nina , Sun Wei-Sheng , Berntsson Ronnie P-A
Published: October 2020

Multidrug resistant bacteria are one of the most important current threats to public health and a serious problem in hospital acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, in a process that is mediated by a protein machinery called the Type 4 Secretion System (T4SS). The core of the T4SS is a multiprotein complex that spans both the cell wall and cellular membrane(s), serving as a channel for macromolecular secretion. Although the majority of multidrug resistant bacteria responsible for HAIs are of Gram-positive origin, with Enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here we describe the structure and organisation of PrgL, one of the seven membrane proteins forming the translocation channel of the T4SS encoded by the pCF10 plasmid fromEnterococcus faecalis. We present the structure of the C-terminal domain of PrgL, which displays similarity to VirB8 proteins of Gram-negative secretion systems. PrgL forms dimers and higher order oligomers but does not interact strongly with the other T4SS components.In vitroexperiments show that the soluble domain alone is enough to drive both dimerization and dodecamerisation, with a dimerization interface that differs from all other known VirB8-like proteins. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.
Dynamic connectivity analyses of intracranial EEG during recognition memory reveal various large-scale functional networks
Authors: Kopal Jakub , Hlinka Jaroslav , Despouy Elodie , Valton Luc , Denuelle Marie , Sol Jean-Christophe , Curot Jonathan , Barbeau Emmanuel J.
Published: October 2020

Recognition memory is the ability to recognize previously encountered events, objects, or people. It is characterized by its robustness and rapidness. Even this relatively simple ability requires the coordinated activity of a surprisingly large number of brain regions. These spatially distributed, but functionally linked regions are interconnected into large-scale networks. Understanding memory requires an examination of the involvement of these networks and the interactions between different regions while memory processes unfold. However, little is known about the dynamical organization of large-scale networks during the early phases of recognition memory. We recorded intracranial EEG, which affords high temporal and spatial resolution, while epileptic subjects performed a visual recognition memory task. We analyzed dynamic functional and effective connectivity as well as network properties. Various networks were identified, each with its specific characteristics regarding information flow (feedforward or feedback), dynamics, topology, and stability. The first network mainly involved the right visual ventral stream and bilateral frontal regions. It was characterized by early predominant feedforward activity, modular topology, and high stability. It was followed by the involvement of a second network, mainly in the left hemisphere, but notably also involving the right hippocampus, characterized by later feedback activity, integrated topology, and lower stability. The transition between networks was associated with a change in network topology. Overall, these results confirm that several large-scale brain networks, each with specific properties and temporal manifestation, are involved during recognition memory. Ultimately, understanding how the brain dynamically faces rapid changes in cognitive demand is vital to our comprehension of the neural basis of cognition.
Minding The Gap: Range Size And Economic Use Drive Functional Trait Data Shortfall In The Atlantic Forest
Authors: Petisco-Souza Ana Carolina , Brum Fernanda Thiesen , Marcilio-Silva Vinícius , Zwiener Victor P. , Zanella Andressa , Dias Arildo S. , González-Melo Andrés , Jansen Steven , Mazzochini Guilherme G. , Niinemets Ülo , Pillar Valério D. , Sosinski Enio , Marques Márcia C. M. , Carlucci Marcos B.
Published: October 2020

Biodiversity shortfalls are knowledge gaps that may result from uneven sampling through time and space and human interest biases. Gaps in data of functional traits of species may add uncertainty in functional diversity and structure measures and hinder inference on ecosystem functioning and ecosystem services, with negative implications for conservation and restoration practices, such as in Atlantic Forest hotspot. Here we investigate which are the potential drivers of trait data gaps and where geographically they are in the Atlantic Forest. We quantified trait gaps for four key plant functional traits of 2335 trees species, and evaluated which factors drive trait gap at the species and at the geographical level. At the species level, we found larger trait gaps for small-ranged and with no economic use. At the geographical level, we found larger gaps at the Atlantic Forest east coast. Trait gaps were higher away from urban areas, and among species with smaller mean range size and smaller mean economic use of wood, and smaller near protected areas. Efforts on reducing trait gaps of small-ranged and of species with economic use of wood can further advance theory-driven studies and improve knowledge coverage
Haploid mouse germ cell precursors from embryonic stem cells revealXistactivation from a single X chromosome
Authors: Aizawa Eishi , Kaufmann Corinne , Sting Sarah , Freimann Remo , Wutz Anton
Published: October 2020

Mammalian haploid cells have applications for genetic screening and substituting gametic genomes. Here we characterize a culture system for obtaining haploid primordial germ cell-like cells (PCGLCs) from haploid mouse embryonic stem cells (ESCs). We find that a haploid genome is maintained in PGCLCs with a high frequency indicating a substantially lower rate of diploidization than somatic cells. Characterization of the differentiating haploid ESCs reveals thatXistis activated from the single X chromosome. This observation suggests that X chromosome inactivation is initiated in haploid cells consistent with a model where autosomal blocking factors set a threshold for X-linked activators. The germline segregates from the epiblast and differs from somatic lineages in gene expression and epigenetic mechanisms. The ability of primordial germ cells for repressingXistmight contribute to the maintenance of a haploid genome.
The effects ofCSTBduplication on APP/amyloid-β pathology and cathepsin activity in a mouse model
Authors: Wu Yixing , Whittaker Heather T. , Noy Suzanna , Cleverley Karen , Brault Veronique , Herault Yann , Fisher Elizabeth M. C. , Wiseman Frances K.
Published: October 2020

People with Down syndrome (DS), caused by trisomy of chromosome 21 have a greatly increased risk of developing Alzheimer’s disease (AD). This is in part because of triplication of a chromosome 21 gene,APP. This gene encodes amyloid precursor protein, which is cleaved to form amyloid-β that accumulates in the brains of people who have AD. Recent experimental results demonstrate that a gene or genes on chromosome 21, other thanAPP,when triplicated significantly accelerate amyloid pathology in a transgenic mouse model of amyloid-β deposition. Multiple lines of evidence indicate that cysteine cathepsin activity influences APP cleavage and amyloid-β accumulation. Located on human chromosome 21 (Hsa21) is an endogenous inhibitor of cathepsin proteases,CYSTATIN B(CSTB)which is proposed to regulate cysteine cathepsin activityin vivo. Here we determined if three copies of the mouse geneCstbis sufficient to modulate beta amyloid (Aβ) accumulation and cathepsin activity in a transgenicAPPmouse model. Duplication ofCstbresulted in an increase in transcriptional and translational levels ofCstbin the mouse cortex but had no effect on the deposition of insoluble Aβ plaques or the levels of soluble or insoluble Aβ42, Aβ40, or Aβ38in 6-month old mice. In addition, the increased CSTB did not alter the activity of cathepsin B enzyme in the cortex of 3-month old mice. These results indicate that the single-gene duplication ofCstbis insufficient to elicit a disease-modifying phenotype in the dupCstb x tgAPP mice, underscoring the complexity of the genetic basis of AD-DS and the importance of multiple gene interactions in disease.
Photocrystallographic and spectroscopic studies of a model (N,N,O)-donor square-planar nickel(II) nitro complex: in search of high-conversion and stable photoswitchable materials
Authors: Kutniewska Sylwia E. , Krówczyński Adam , Kamiński Radosław , Jarzembska Katarzyna N. , Pillet Sébastien , Wenger Emmanuel , Schaniel Dominik
Published: October 2020

A new, cheap, easy-to-synthesize and air-stable photoswitchable nickel(II) complex, QTNiNO2, is reported. The metal centre in QTNiNO2is coordinated by a nitro group and a [2-methyl-8-aminoquinoline]-1-tetralone ligand. The compound crystallizes in the tetragonal space groupI41/awith one complex molecule comprising the asymmetric unit, and the crystals are stable under ambient conditions. Irradiation of the solid-state form of QTNiNO2with 530–660 nm LED light at 160 K converts the ambidentate nitro moiety fully to the nitrito linkage isomer which is stable up to around 230 K, as indicated by IR spectroscopy measurements. The structures of all species present in the examined crystals and their thermal stability were confirmed via X-ray multi-temperature and photocrystallographic experiments. The impact of temperature on the (photo)isomerization reaction taking place in a single crystal was additionally investigated. The experimental results are supported by computational analyses of crystal packing and intermolecular interactions that influence the isomerization process studied.
High-resolution cryo-EM using beam-image shift at 200 keV
Authors: Cash Jennifer N. , Kearns Sarah , Li Yilai , Cianfrocco Michael A.
Published: October 2020

Recent advances in single-particle cryo-electron microscopy (cryo-EM) data collection utilize beam-image shift to improve throughput. Despite implementation on 300 keV cryo-EM instruments, it remains unknown how well beam-image-shift data collection affects data quality on 200 keV instruments and the extent to which aberrations can be computationally corrected. To test this, a cryo-EM data set for aldolase was collected at 200 keV using beam-image shift and analyzed. This analysis shows that the instrument beam tilt and particle motion initially limited the resolution to 4.9 Å. After particle polishing and iterative rounds of aberration correction in RELION, a 2.8 Å resolution structure could be obtained. This analysis demonstrates that software correction of microscope aberrations can provide a significant improvement in resolution at 200 keV.
Hirshfeld atom like refinement with alternative electron density partitions
Authors: Chodkiewicz Michał Leszek , Woińska Magdalena , Woźniak Krzysztof
Published: October 2020

Hirshfeld atom refinement is one of the most successful methods for the accurate determination of structural parameters for hydrogen atoms from X-ray diffraction data. This work introduces a generalization of the method [generalized atom refinement (GAR)], consisting of the application of various methods of partitioning electron density into atomic contributions. These were tested on three organic structures using the following partitions: Hirshfeld, iterative Hirshfeld, iterative stockholder, minimal basis iterative stockholder and Becke. The effects of partition choice were also compared with those caused by other factors such as quantum chemical methodology, basis set, representation of the crystal field and a combination of these factors. The differences between the partitions were small in terms ofRfactor (e.g.much smaller than for refinements with different quantum chemistry methods,i.e.Hartree–Fock and coupled cluster) and therefore no single partition was clearly the best in terms of experimental data reconstruction. In the case of structural parameters the differences between the partitions are comparable to those related to the choice of other factors. We have observed the systematic effects of the partition choice on bond lengths and ADP values of polar hydrogen atoms. The bond lengths were also systematically influenced by the choice of electron density calculation methodology. This suggests that GAR-derived structural parameters could be systematically improved by selecting an optimal combination of the partition and quantum chemistry method. The results of the refinements were compared with those of neutron diffraction experiments. This allowed a selection of the most promising partition methods for further optimization of GAR settings, namely the Hirshfeld, iterative stockholder and minimal basis iterative stockholder.
Crystal structure of monoclinic hafnia (HfO2) revisited with synchrotron X-ray, neutron diffraction and first-principles calculations
Authors: Pathak Santanu , Das Parnika , Das Tilak , Mandal Guruprasad , Joseph Boby , Sahu Manjulata , Kaushik S. D. , Siruguri Vasudeva
Published: October 2020

A study on the crystal structure of monoclinic HfO2 has been performed using synchrotron X-ray and neutron diffraction data separately, as well as a combination of both. The precision of the structural parameters increases significantly due to application of the neutron diffraction technique. The experimental oxygen positions in HfO2, derived precisely, are visualized only by semi-local density functional calculations in terms of the calculated electronic band gap, but are not captured as accurately by using hybrid functionals.
Have changes in audit standards altered client perceptions of auditors?
Authors: Doxey Marcus , Ewing Robert
Published: October 2020

Purpose

Changes in external auditing over four decades motivates a historical investigation of how client employees' perceptions of auditors have changed across this period.

Design/methodology/approach

This paper uses a longitudinal quasi-experiment to compare current client employees' perceptions of the auditor with results from 1972.

Findings

Changes in client employees' perceptions of the audit, its usefulness and of auditor-client conflict suggest increases in auditor independence. However, this paper also finds that despite decades of efforts to strengthen auditor independence and skepticism, the primary analogy client employees apply to the external auditor remains “consultant”.

Practical implications

The findings contribute to the discussion of whether regulatory and standard changes in the audit environment have changed aspects of client employees' perceptions of auditors.

Originality/value

The paper contributes by presenting a unique approach to partially replicating a historic study using a quasi-experimental research design.
Entrepreneurial orientation, new product development and firm performance: the moderating role of legitimacy in Chinese high-tech SMEs
Authors: Liu Yunqing , Wang Min
Published: October 2020

Purpose

This paper examines the relationship of entrepreneurial orientation (EO), new product development (NPD), legitimacy (political and market) and firm performance (FP). The authors investigate how and when EO improves FP in high-tech small and medium-size enterprises (SMEs).

Design/methodology/approach

The paper formulates 5 hypotheses from literature review and theoretical deduction. The hypotheses are tested using ordinary least squares (OLS) regression with data collected from 219 randomly selected SMEs operating in high-tech industries of China.

Findings

The findings show that the mechanism of EO improve FP in high-tech SMEs by considering NPD as a mediator and legitimacy as moderators: (1) NPD plays a mediating role in the relationship between EO and FP, (2) market legitimacy (ML) positively moderating the effect of EO on FP and (3) both political legitimacy (PL) and ML positively moderating the effect of NPD on FP.

Research limitations/implications

For the limitations, the firms the authors’ surveyed are SMEs that are not listed companies, which cause some limitations. For the implications, the authors propose some recommendations based on the findings to help Chinese SMEs to enhance performance.

Originality/value

The existing research on EO–FP linkage remains elusive findings. The paper reconciled the inconsistency by providing a nuanced mechanism of how EO promotes FP in high-tech SMEs of Chinese transition economy. By explain the important role of NPD in high-tech SMEs, the findings shed light on the mediators between EO and FP and the moderators. By emphasize the different role of ML and PL in determining EO–FP and NPD–FP linkages, the findings illustrate the peculiarity of contingency factors in a transition economy.
Prevalence of COPD by age, sex, socioeconomic position and smoking status; a cross-sectional study
Authors: Levin Kate Ann , Anderson David , Crighton Emilia
Published: October 2020

Purpose

The purpose of this study is to calculate gender and socioeconomic status (SES) inequalities in chronic obstructive pulmonary disease (COPD) in Greater Glasgow and Clyde and measure the proportion of inequalities explained by smoking.

Design/methodology/approach

Medical records until May 2016 were linked to mortality data to measure COPD prevalence. Population estimates for smoking status were calculated by merging three (2013–2015) Scottish Household Survey rounds. Poisson regression was carried out to analyse the relationship between SES and gender inequalities in COPD, and smoking.

Findings

Crude COPD prevalence for ages 16+ years was 3.29% and for ages 45 years+ was 6.26%, and higher in females than males. Adjusting for age and sex, prevalence of COPD in the most deprived quintile was 4.5 times of that in the least deprived. Adjustment for smoking explains almost half of the relative difference between Scottish Indicator for Multiple Deprivation (SIMD) 1 (least affluent quintile of deprivation) and SIMD 5 (most affluent quintile) and a fifth of the absolute difference. There is a higher risk of COPD among male non-smokers than female, but among smokers the risk is greater for females than males.

Research limitations/implications

Risk factors specific to respiratory health beyond smoking and common risk factors of morbidity more generally should be considered in understanding inequalities in COPD.

Originality/value

Prevalence of COPD is higher than previously thought. Smoking explains less than half of inequalities in COPD. Gender inequalities in COPD are dependent on smoking status and the smoking indicator used.
Public health leadership in the times of COVID-19: a comparative case study of three countries
Authors: Glenn Jeffrey , Chaumont Claire , Villalobos Dintrans Pablo
Published: October 2020

Purpose

The purpose is to understand the role of public leadership during the COVID-19 pandemic and advocate for a more active role of public health professionals in helping manage the crisis.

Design/methodology/approach

The authors use the framework developed by Boinet al.(2005) on crisis leadership. The authors focus on three of the core tasks – sense-making, decision-making and meaning-making – that are relevant to explain the role of public leaders during the ongoing crisis. The authors draw from the experience of three countries – Chile, France and the United States – to illustrate how these tasks were exercised with concrete examples.

Findings

Several examples of the way in which public leaders reacted to the crisis are found in the selected countries. Countries show different responses to the way they assessed and reacted to the COVID-19 as a crisis, the decisions taken to prevent infections and mitigate consequences, and the way they communicate information to the population.

Practical implications

A better understanding public leadership as a key for better crisis management, particularly for designing policy responses to public health crises. Public health leaders need to assume a more active role in the crisis management process, which also implies the emergence of a new class of public health leaders and a more prominent role for public health in the public eye.

Originality/value

The use of examples from three different countries, as well as the focus on the core leadership tasks during an ongoing crisis help not only assessing the crisis management but also extracting lessons for the coming months, as well as future public health emergencies. The three authors have a first-hand experience on the evolution of the crisis in their countries and the environment, since they are currently living and working in public health in Chile, France and the United States.
Predicting behavioural intentions of Craft Beer Festival attendees by their event experience
Authors: Hermann Uwe Peter , Lee Craig , Coetzee Willem , Boshoff Liezel
Published: October 2020

Purpose

The purpose of this paper is to contribute to the event experience literature by examining the effects of Craft Beer Festival attendee’s event experience on their satisfaction and behavioural intentions. The study also investigates whether these relationships are moderated by the attendee’s past history with the festival and the distance they have travelled to attend the event.

Design/methodology/approach

The theoretically derived model was tested on a sample of 354 attendees of the Capital Craft Beer Festival in Pretoria, South Africa. Partial least squares structural equation modelling was used to analyse the data.

Findings

The results indicated that only affective engagement positively influences attendee’s satisfaction, which, in turn, positively influences attendee’s intentions to revisit and recommend the beer festival. The authors found no evidence of the effects of cognitive and physical engagement and experiencing novelty on event satisfaction and no moderating effect of previous attendance and distance travelled to the event.

Originality/value

The findings advance the knowledge base in the field of a gastronomic event experience regarding critical factors that affect event satisfaction which, to date, have only been tested on sports events.
High-performance computing for computational modelling in built environment-related studies – a scientometric review
Authors: Aghimien Emmanuel Imuetinyan , Aghimien Lerato Millicent , Petinrin Olutomilayo Olayemi , Aghimien Douglas Omoregie
Published: October 2020

Purpose

This paper aims to present the result of a scientometric analysis conducted using studies on high-performance computing in computational modelling. This was done with a view to showcasing the need for high-performance computers (HPC) within the architecture, engineering and construction (AEC) industry in developing countries, particularly in Africa, where the use of HPC in developing computational models (CMs) for effective problem solving is still low.

Design/methodology/approach

An interpretivism philosophical stance was adopted for the study which informed a scientometric review of existing studies gathered from the Scopus database. Keywords such as high-performance computing, and computational modelling were used to extract papers from the database. Visualisation of Similarities viewer (VOSviewer) was used to prepare co-occurrence maps based on the bibliographic data gathered.

Findings

Findings revealed the scarcity of research emanating from Africa in this area of study. Furthermore, past studies had placed focus on high-performance computing in the development of computational modelling and theory, parallel computing and improved visualisation, large-scale application software, computer simulations and computational mathematical modelling. Future studies can also explore areas such as cloud computing, optimisation, high-level programming language, natural science computing, computer graphics equipment and Graphics Processing Units as they relate to the AEC industry.

Research limitations/implications

The study assessed a single database for the search of related studies.

Originality/value

The findings of this study serve as an excellent theoretical background for AEC researchers seeking to explore the use of HPC for CMs development in the quest for solving complex problems in the industry.