bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural insights into the mechanism of rhodopsin phosphodiesterase
Authors: Ikuta Tatsuya , Shihoya Wataru , Sugiura Masahiro , Yoshida Kazuho , Watari Masahito , Tokano Takaya , Yamashita Keitaro , Katayama Kota , Tsunoda Satoshi P. , Uchihashi Takayuki , Kandori Hideki , Nureki Osamu
Published: April 2020

Rhodopsin phosphodiesterase (Rh-PDE) is an enzyme rhodopsin belonging to a recently discovered class of microbial rhodopsins with light-dependent enzymatic activity. Rh-PDE consists of the N-terminal rhodopsin domain and C-terminal phosphodiesterase (PDE) domain, connected by 76-residue linker, and hydrolyzes both cAMP and cGMP in a light-dependent manner. Thus, Rh-PDE has potential for the optogenetic manipulation of cyclic nucleotide concentrations, as a complementary tool to rhodopsin guanylyl cyclase (Rh-GC) and photosensitive adenylyl cyclase (PAC). Here we present structural and functional analyses of the Rh-PDE derived from Salpingoeca rosetta. The 2.6 Å resolution crystal structure of the transmembrane domain revealed a new topology of rhodopsin, with 8 TMs including the N-terminal extra TM, TM0. Mutational analyses demonstrated that TM0 plays a crucial role in the enzymatic photoactivity. We further solved the crystal structures of the transmembrane and PDE domain (2.1 Å) with their connecting linkers. Integrating these structures, we proposed a model of full-length Rh-PDE, based on the HS-AFM observations and computational modeling of the linker region. These findings provide insight into the photoactivation mechanisms of other 8-TM enzyme rhodopsins and expand the definition of rhodopsins.
A faster implementation of association mapping from k-mers
Authors: Mehrab Zakaria , Mobin Jaiaid , Tahmid Ibrahim Asadullah , Rahman Atif
Published: April 2020

Genome wide association studies (GWAS) attempt to map genotypes to phenotypes in organisms. This is typically performed by genotyping individuals using microarray or by aligning whole genome sequencing reads to a reference genome. Both approaches require knowledge of a reference genome which limits their application to organisms with no or incomplete reference genomes. This caveat can be removed using alignment-free association mapping methods based on k-mers from sequencing reads. Here we present an implementation of an alignment free association mapping method [1] to improve its execution time and flexibility. We have tested our implementation on anE. Coliampicillin resistance dataset and observe improvement in performance over the original implementation while maintaining accuracy in results. Finally, we demonstrate that the method can be applied to find sex specific sequences.
Dietary supplementation with products of Citrus reticulata "Chachi" for improving the fecal microbiome of weaned piglets
Authors: Lin Huafeng , Li Gang , Wang Haizhen , Li Lili , Chen Xun , Shi Lei , Tang Yong , Chang Yanlei , Yang Jie , Liu Yuqi , Gong Hanyue
Published: April 2020

Nutritional interventions play a critical role in modifying the intestinal microbiome of host animals. This study was conducted to interrogate the physiological effects on fecal microflora of weaned piglets via the dietary supplemented with two types of products of Citrus reticulata "Chachi", respectively. For this purpose, A total of 72 piglets with uniform sizes were randomly assigned to four dietary treatment groups consisted of a negative control group (NCG), a fermented citrus reticulata "Chachi" pulp group (FCRPG), a Citri Reticulatae Pericarpium group (CRPG) and a positive control group (PCG) in a 21-day feeding trial. After the raising experiment, fresh feces of piglets were analyzed systematically using multi-omics technologies. Metagenomics method with high-throughput compositional characterization indicated that the architecture and diversity of fecal microbiome were both influenced by these two additives and compound antibiotics. Metabolite analysis showed that FCRPG have an significant effects on fecal short-chain fatty acids (SCFAs) among four treatment groups. Results of functional proteomics approaches found that FCRPG presented the highest butyrate metabolic level, and CRPG showed the highest flavone and flavonol biosynthesis level in feces. In addition, NCP produced an effective effect on adjusting fecal microbiome proflie. Consequently, our findings demonstrate that dietary supplementation with FCRP or CRP modulates the microbial taxa, metabolic and proteomic alterations in fecal microbiota of weaned piglets for health maintaining.
The prevalence and genomic context of Shiga toxin 2a genes inE. colifound in cattle
Authors: Jinnerot Tomas , Tomaselli Angeles Tatiana Ponton , Johannessen Gro S , Söderlund Robert , Urdahl Anne Margrete , Aspán Anna , Sekse Camilla
Published: April 2020

Shiga toxin-producingEscherichia coli(STEC) that cause severe disease predominantly carry the toxin gene variantstx2a. However, the role of Shiga toxin in the ruminant reservoirs of this zoonotic pathogen is poorly understood and strains that cause severe disease in humans (HUSEC) likely constitute a small and atypical subset of the overall STEC flora. The aim of this study was to investigate the presence ofstx2ain samples from cattle and to isolate and characterizestx2a-positiveE. coli. In nationwide surveys in Sweden and Norway samples were collected from individual cattle or from cattle herds, respectively. Samples were tested for Shiga toxin genes by real-time PCR and amplicon sequencing andstx2a-positive isolates were whole genome sequenced. Among faecal samples from Sweden,stx1was detected in 37%,stx2in 53% andstx2ain 5% and in skin samples in 64%, 79% and 2% respectively. In Norway, 79% of the herds were positive forstx1, 93% forstx2and 17% forstx2a. Based on amplicon sequencing the most commonstx2types in samples from Swedish cattle werestx2aandstx2d. Multilocus sequence typing (MLST) of 39stx2a-positive isolates collected from both countries revealed substantial diversity with 19 different sequence types. Only a few classical LEE-positive HUSEC were found among thestx2a-positive isolates, notably a single O121:H19 and an O26:H11. Known LEE-negative HUSEC lineages were also recovered including O113:H21 (ST-223), O130:H11 (ST-297), and O101:H33 (ST-330). We conclude thatE. coliencodingstx2ain cattle are ranging from well-known HUSEC to unknown STEC variants. Comparison of isolates from human HUS cases to related STEC from the ruminant reservoirs can help identify combinations of virulence attributes necessary to cause HUS, as well as provide a better understanding of the routes of infection for rare and emerging pathogenic STEC.
A new automated chilled adult release system for the aerial distribution of sterile male tsetse flies
Authors: Mirieri Caroline , Mutika Gratian N , Bruno Jimmy , Seck Momar Talla , Sall Baba , Parker Andrew G. , van Oers Monique M. , Vreysen Marc J.B. , Bouyer Bouyer , Abd-Alla Adly M.M.
Published: April 2020

Background: Tsetse flies transmit trypanosomes that cause the debilitating diseases human African trypanosomosis (HAT) or sleeping sickness in humans and animal African trypanosomosis (AAT) or nagana in livestock. The riverine tsetse species Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The Government of Senegal has embarked on a project to eliminate a population of this tsetse species from the Niayes area with the objective to manage AAT in the area. The project is implemented following an area-wide integrated pest management approach with an SIT component. The SIT can only be successful when the sterile males that are released in the field are of high biological quality, i.e. have the same dispersal capacity, survival and competitiveness as their wild counterparts. To date, sterile tsetse males have been released by air using biodegradable cardboard cartons that were manually dropped from a fixed-wing aircraft or gyrocopter. The cardboard boxes are however expensive, and the system is rather cumbersome to implement. Methods: A new prototype of an automated chilled adult release system (Bruno Spreader Innovation, (BSI™)) for tsetse flies was tested for its accuracy (in counting numbers of sterile males as loaded into the machine), release rate consistency and impact on quality of the released males. The impact of the release process was evaluated on several performance indicators of the irradiated male flies such as flight propensity, survival, mating competitiveness, premating and mating duration, and insemination rate of mated females. Results: The BSI TM release system counted with a consistent accuracy and released homogenously tsetse flies at the lowest motor speed (0.6 rpm). In addition, the chilling conditions (6 ± 1 o C) and the release process (passing of flies through the machine) had no significant negative impact on the males' flight propensity. No significant differences were observed between the control males (no irradiation and no exposure to the release process), irradiated males (no exposure to the release process) and irradiated males exposed to the release process with respect to mating competitiveness, premating period and mating duration. Only survival of irradiated males that were exposed to the release process was reduced, irrespective of whether the males were held with or without feeding. Conclusion: Although the release process had a negative effect on survival of the flies, the data of the experiments indicate that the BSI machine holds promise for use in operational tsetse SIT programmes. The promising results of this study will now need to be confirmed under operational field conditions in West Africa.
Midkine-a functions as a universal regulator of proliferation during epimorphic regeneration in adult zebrafish
Authors: Ang Nicholas B , Saera-Vila Alfonso , Walsh Caroline , Hitchcock Peter F , Kahana Alon , Thummel Ryan , Nagashima Mikiko
Published: April 2020

Zebrafish have the ability to regenerate damaged cells and tissues by activating quiescent stem and progenitor cells or reprogramming differentiated cells into regeneration-competent precursors. Proliferation among the cells that will functionally restore injured tissues is a fundamental biological process underlying regeneration. Midkine-a is a cytokine growth factor, whose expression is strongly induced by injury in a variety of tissues across a range of vertebrate classes. Using a zebrafish Midkine-a loss of function mutant, we evaluated regeneration of caudal fin, extraocular muscle and retinal neurons to investigate the function of Midkine-a during epimorphic regeneration. In wildtype zebrafish, injury among these tissues induces robust proliferation and rapid regeneration. In Midkine-a mutants, the initial proliferation in each of these tissues is significantly diminished or absent. Regeneration of the caudal fin and extraocular muscle is delayed; regeneration of the retina is nearly completely absent. These data demonstrate that Midkine-a is universally required in the signaling pathways that convert tissue injury into the initial burst of cell proliferation. Further, these data highlight differences in the molecular mechanisms that regulate epimorphic regeneration in zebrafish.
One is not enough: on the effects of reference genome for the mapping and subsequent analyses of short-reads
Authors: Valiente-Mullor Carlos , Beamud Beatriz , Ansari Iván , Francés-Cuesta Carlos , García-González Neris , Mejía Lorena , Ruiz-Hueso Paula , González-Candelas Fernando
Published: April 2020

Mapping of high-throughput sequencing (HTS) reads to a single arbitrary reference genome is a frequently used approach in microbial genomics. However, the choice of a reference may represent a source of errors that may affect subsequent analyses such as the detection of single nucleotide polymorphisms (SNPs) and phylogenetic inference. In this work, we evaluated the effect of reference choice on short-read sequence data from five clinically and epidemiologically relevant bacteria (Klebsiella pneumoniae, Legionella pneumophila, Neisseria gonorrhoeae, Pseudomonas aeruginosa and Serratia marcescens). Publicly available whole-genome assemblies encompassing the genomic diversity of these species were selected as reference sequences, and read alignment statistics, SNP calling, recombination rates, dN/dS ratios, and phylogenetic trees were evaluated depending on the mapping reference. The choice of different reference genomes proved to have an impact on almost all the parameters considered in the five species. In addition, these biases had potential epidemiological implications such as including/excluding isolates of particular clades and the estimation of genetic distances. These findings suggest that the single reference approach might introduce systematic errors during mapping that affect subsequent analyses, particularly for data sets with isolates from genetically diverse backgrounds. In any case, exploring the effects of different references on the final conclusions is highly recommended.

Author summary

Mapping consists in the alignment of reads (i.e., DNA fragments) obtained through high-throughput genome sequencing to a previously assembled reference sequence. It is a common practice in genomic studies to use a single reference for mapping, usually the ‘reference genome’ of a species —a high-quality assembly. However, the selection of an optimal reference is hindered by intrinsic intra-species genetic variability, particularly in bacteria. Biases/errors due to reference choice for mapping in bacteria have been identified. These are mainly originated in alignment errors due to genetic differences between the reference genome and the read sequences. Eventually, they could lead to misidentification of variants and biased reconstruction of phylogenetic trees (which reflect ancestry between different bacterial lineages). However, a systematic work on the effects of reference choice in different bacterial species is still missing, particularly regarding its impact on phylogenies. This work intended to fill that gap. The impact of reference choice has proved to be pervasive in the five bacterial species that we have studied and, in some cases, alterations in phylogenetic trees could lead to incorrect epidemiological inferences. Hence, the use of different reference genomes may be prescriptive to assess the potential biases of mapping.
Characterizing the portability of RecT-mediated oligonucleotide recombination
Authors: Filsinger Gabriel T. , Wannier Timothy M. , Pedersen Felix B. , Lutz Isaac D. , Zhang Julie , Stork Devon A. , Debnath Anik , Gozzi Kevin , Kuchwara Helene , Volf Verena , Wang Stan , Rios Xavier , Gregg Christopher J. , Lajoie Marc J. , Shipman Seth L. , Aach John , Laub Michael T. , Church George M.
Published: April 2020

Bacterial genome editing methods are used to engineer strains for biotechnology and fundamental research. Homologous recombination (HR) is the most versatile method of genome editing, but traditional techniques using endogenous RecA-mediated pathways are inefficient and laborious. Phage encoded RecT proteins can improve HR over 1000-fold, but these proteins have limited portability between species. UsingEscherichia coli,Lactococcus lactis, Mycobacterium smegmatis, Lactobacillus rhamnosus, andCaulobacter crescentuswe investigated the hostlimited functionality of RecTs. We find that these proteins specifically recognize the 7 C-terminal amino acids of the bacterial single-stranded DNA-binding protein (SSB), and are portable between species only if compatibility with this host domain is maintained. Furthermore, in some species, we find that co-expressing otherwise incompatible RecTs with a paired bacterial SSB is sufficient to establish functionality. Finally, we demonstrate that high-efficiency HR surpasses the mutational capacity of more widely used error-prone methods for genome diversification, and can be used to identify exceptional phenotypes inaccessible through sequential nucleotide conversions.
Deep Active Inference and Scene Construction
Authors: Heins R. Conor , Mirza M. Berk , Parr Thomas , Friston Karl , Kagan Igor , Pooresmaeili Arezoo
Published: April 2020

Adaptive agents must act in intrinsically uncertain environments with complex latent structure. Here, we elaborate a model of visual foraging – in a hierarchical context – wherein agents infer a higher-order visual pattern (a ‘scene’) by sequentially sampling ambiguous cues. Inspired by previous models of scene construction – that cast perception and action as consequences of approximate Bayesian inference – we use active inference to simulate decisions of agents categorizing a scene in a hierarchically-structured setting. Under active inference, agents develop probabilistic beliefs about their environment, while actively sampling it to maximise the evidence for their internal generative model. This approximate evidence maximization (i.e. self-evidencing) comprises drives to both maximise rewards and resolve uncertainty about hidden states. This is realised via minimization of a free energy functional of posterior beliefs about both the world as well as the actions used to sample or perturb it, corresponding to perception and action, respectively. We show that active inference, in the context of hierarchical scene construction, gives rise to many empirical evidence accumulation phenomena, such as noise-sensitive reaction times and epistemic saccades. We explain these behaviours in terms of the principled drives that constitute theexpected free energy, the key quantity for evaluating policies under active inference. In addition, we report novel behaviours exhibited by these active inference agents that furnish new predictions for research on evidence accumulation and perceptual decision-making. We discuss the implications of this hierarchical active inference scheme for tasks that require planned sequences of information-gathering actions to infer compositional latent structure (such as visual scene construction and sentence comprehension). Finally, we propose experiments to contextualise active inference in relation to other formulations of evidence accumulation (e.g. drift-diffusion models) in tasks that require planning in uncertain environments with higher-order structure.
Phylogenetic Analysis of the Novel Coronavirus Reveals Important Variants in Indian Strains
Authors: Joshi Aditi , Paul Sushmita
Published: April 2020

Recently classified as a pandemic by WHO, novel Corononavirus 2019 has affected almost every corner of the globe causing human deaths in a range of hundred thousands. The virus having its roots in Wuhan (China) has been spread over the world by its own property to change itself accordingly. These changes correspond to its transmission and pathogenicity due to which the concept of social distancing appeared into the picture. In this paper, a few findings from the whole genome sequence analysis of viral genome sequences submitted from India are presented. The data used for analysis comprises 440 collective genome sequences of virus submitted in GenBank, GISAID, and SRA projects, from around the world as well as 28 viral sequences from India. Multiple sequence alignment of all genome sequences was performed and analysed. A novel non-synonymous mutation 4809C>T (S1515F) in NSP3 gene of SARS-CoV2 Indian strains is reported along with other frequent and important changes from around the world: 3037C>T, 14408C>T, and 23403A>G. The novel change was observed in samples collected in the month of March, whereas was found to be absent in samples collected in January with the respective persons’ travel history to China. Phylogenetic analysis clustered the sequences with this change as one separate clade. Mutation was predicted as stabilising change by insilco tool DynaMut. A second patient in the world to our knowledge with multiple (Wuhan and USA) strain contraction was observed in this study. The infected person is among the two early infected patients with travel history to China. Strains sequenced in Iran stood out to have different variants, as most of the reported frequent variants were not observed. The objective of this paper is to highlight the similarities and changes observed in the submitted Indian viral strains. This helps to keep track on the activity, that how virus is changing into a new subtype. Major strains observed were European with the novel change in India and other being emergent clade of Iran. Its important to observe the changes in NSP3 gene, as this gene has been reported with extensive positive selection as well as potential drug target. Extensive Positive Selection Drives the Evolution of Nonstructural Proteins. With the limited number of sequences this was the only frequent novel non-synonymous change observed from Indian strains, thereby making this change vulnerable for investigation in future. This paper has a special focus on tracking of Indian viral sequences submitted in public domain.
Horizontal gene transfer barrier shapes the evolution of prokaryotic pangenomes
Authors: Sela Itamar , Wolf Yuri I. , Koonin Eugene V.
Published: April 2020

The genomes of bacteria and archaea evolve by extensive loss and gain of genes which, for any group of related prokaryotic genomes, result in the formation of a pangenome with the universal, asymmetrical U-shaped distribution of gene commonality. To elucidate the evolutionary factors that define the specific shape of this distribution, we investigate the fit of simple models of genome evolution to the empirically observed gene commonality distributions and genomes intersections for 33 groups of closely related bacterial genomes. The combined analysis of genome intersections and gene commonality shows that at least one of the two simplifying assumptions that are usually adopted for modeling the evolution of the U-shaped distribution, those of infinitely many genes and constant genome size, is invalid. The violation of both these assumptions stems from the horizontal gene transfer barrier,i.e. the cost of accommodation of foreign genes by prokaryotes.
A multi-layered and dynamic apical extracellular matrix shapes the vulva lumen inCaenorhabditis elegans
Authors: Cohen Jennifer D. , Sparacio Alessandro P. , Belfi Alexandra C. , Forman-Rubinsky Rachel , Hall David H. , Maul-Newby Hannah M. , Frand Alison R. , Sundaram Meera V.
Published: April 2020

Biological tubes must develop and maintain their proper diameter in order to transport materials efficiently. These tubes are molded and protected in part by apical extracellular matrices (aECMs) that line their lumens. Despite their importance, aECMs are difficult to imagein vivoand therefore poorly understood. TheC. elegansvulva has been a paradigm for understanding many aspects of organogenesis. Here we describe the vulva luminal matrix, which contains chondroitin proteoglycans, Zona Pellucida (ZP) domain proteins, and other glycoproteins and lipid transporters related to those in mammals. Confocal and transmission electron microscopy revealed, with unprecedented detail, a complex and dynamic aECM. Different matrix factors assemble on the apical surfaces of each vulva cell type, with clear distinctions seen between Ras-dependent (1°) and Notch-dependent (2°) cell types. Genetic perturbations suggest that chondroitin and other aECM factors together generate a structured scaffold that both expands and constricts lumen shape.
LSD1 inhibitors induce neuronal differentiation of Merkel cell carcinoma by disrupting the LSD1-CoREST complex and activating TGFβ signaling
Authors: Leiendecker Lukas , Jung Pauline S. , Neumann Tobias , Wiesner Thomas , Obenauf Anna C.
Published: April 2020

Merkel cell carcinoma (MCC) is a highly aggressive, neuroendocrine skin cancer that is either associated with the clonal integration of the Merkel cell polyomavirus or with chronic sun exposure1,2. Immunotherapy is initially effective in many patients with metastatic MCC, but the response is rarely durable3,4. MCC lacks actionable mutations that could be utilized for targeted therapies, but epigenetic regulators, which govern cell fate, provide unexplored therapeutic entry points. Here, we performed a pharmacological screen in MCC cells, targeting epigenetic regulators. We discovered that the lysine-specific histone demethylase 1A (LSD1/KDM1A) is required for MCC growthin vitroandin vivo. HMG20B (BRAF35), a poorly characterized subunit of the LSD1-CoREST complex, is also essential for MCC proliferation. LSD1 inhibition in MCC disrupts the LSD1-CoREST complex, directly induces the expression of key regulators of the neuronal lineage and of members of the TGFβ pathway, and activates a gene expression signature corresponding to normal Merkel cells. Our results provide a rationale for evaluating LSD1 inhibitors, which are currently being tested in patients with leukemia and solid tumors, in MCC.
Specific splice junction detection in single cells with SICILIAN
Authors: Dehghannasiri Roozbeh , Olivieri Julia Eve , Salzman Julia
Published: April 2020

Precise splice junction calls are currently unavailable in scRNA-seq pipelines such as the 10x Chromium platform but are critical for understanding single-cell biology. Here, we introduce SICILIAN, a new method that assigns statistical confidence to splice junctions from a spliced aligner to improve precision. SICILIAN’s precise splice detection achieves high accuracy on simulated data, improves concordance between matched single-cell and bulk datasets, increases agreement between biological replicates, and reliably detects un-annotated splicing in single cells, enabling the discovery of novel splicing regulation.
Rapid acquisition through fast mapping: stable memory over time and role of prior knowledge
Authors: Li Cuihong , Hu Zhongyu , Yang Jiongjiong
Published: April 2020

In recent years, there have been intensive debates on whether healthy adults acquire new word knowledge through fast mapping (FM) by a different mechanism from explicit encoding (EE). In this study, we focused on this issue and investigated to what extent retention interval, prior knowledge (PK), and lure type modulated memory after FM and EE. Healthy young participants were asked to learn novel word-picture associations through both FM and EE. Half of the pictures were from familiar categories (i.e., high PK) and the other half were from unfamiliar categories (i.e., low PK). After 10 min and 1 wk, the participants were tested by forced-choice (FC) tasks, with lures from different categories (Experiment 1) or from the same categories of the target pictures (Experiment 2). Pseudowords were used to denote names of the novel pictures and baseline performance was controlled for each task. The results showed that in both Experiments 1 and 2, memory performance remained stable after FM, while it declined after EE from 10 min to 1 wk. Moreover, the effect of PK appeared at 10 min after FM while at 1 wk after EE in Experiment 2. PK enhanced memory of word-picture associations when the lures were from the same categories (Experiment 2), rather than from different categories (Experiment 1). These results were largely confirmed in Experiment 3 when encoding condition was manipulated as a between-subjects factor, while lure type as a within-subjects factor. The findings suggest that different from EE, FM facilitates rapid acquisition and consolidation of word-picture knowledge, and highlight that PK plays an important role in this process by enhancing access to detailed information.
Checking responses of goal- and sign-trackers are differentially affected by threat in a rodent analog of obsessive–compulsive disorder
Authors: Vousden George H. , Paulcan Sloane , Robbins Trevor W. , Eagle Dawn M. , Milton Amy L.
Published: April 2020

In obsessive–compulsive disorder (OCD), functional behaviors such as checking that a door is locked become dysfunctional, maladaptive, and debilitating. However, it is currently unknown how aversive and appetitive motivations interact to produce functional and dysfunctional behavior in OCD. Here we show a double dissociation in the effects of anxiogenic cues and sensitivity to rewarding stimuli on the propensity to develop functional and dysfunctional checking behavior in a rodent analog of OCD, the observing response task (ORT). While anxiogenic manipulations of perceived threat (presentation of threat-associated contextual cues) and actual threat (punishment of incorrect responding on the ORT) enhanced functional checking, dysfunctional checking was unaffected. In contrast, rats that had previously been identified as “sign-trackers” on an autoshaping task—and therefore were highly sensitive to the incentive salience of appetitive environmental cues—selectively showed elevated levels of dysfunctional checking under a range of conditions, but particularly so under conditions of uncertainty. These data indicate that functional and dysfunctional checking are dissociable and supported by aversive and appetitive motivational processes, respectively. While functional checking is modulated by perceived and actual threat, dysfunctional checking recruits appetitive motivational processes, possibly akin to the “incentive habits” that contribute to drug-seeking in addiction.
The modulated low-temperature structure of malayaite, CaSnOSiO4
Authors: Malcherek Thomas , Paulenz Bianca , Fischer Michael , Paulmann Carsten
Published: April 2020

The crystal structure of the mineral malayaite has been studied by single-crystal X-ray diffraction at a temperature of 20 K and by calculation of its phonon dispersion using density functional perturbation theory. The X-ray diffraction data show first-order satellite diffraction maxima at positionsq= 0.2606 (8)b*, that are absent at room temperature. The computed phonon dispersion indicates unstable modes associated with dynamic displacements of the Ca atoms. The largest-frequency modulus of these phonon instabilities is located close to a wavevector ofq= 0.3b*. These results indicate that the malayaite crystal structure is incommensurately modulated by static displacement of the Ca atoms at low temperatures, caused by the softening of an optic phonon withBgsymmetry.
Structure of P46, an immunodominant surface protein fromMycoplasma hyopneumoniae: interaction with a monoclonal antibody
Authors: Guasch Alicia , Montané Jordi , Moros Alexandra , Piñol Jaume , Sitjà Marta , González-González Luis , Fita Ignasi
Published: April 2020

Mycoplasma hyopneumoniaeis a prokaryotic pathogen that colonizes the respiratory ciliated epithelial cells in swine. Infected animals suffer respiratory lesions, causing major economic losses in the porcine industry. Characterization of the immunodominant membrane-associated proteins fromM. hyopneumoniaemay be instrumental in the development of new therapeutic approaches. Here, the crystal structure of P46, one of the main surface-antigen proteins, fromM. hyopneumoniaeis presented and shows N- and C-terminal α/β domains connected by a hinge. The structures solved in this work include a ligand-free open form of P46 (3.1 Å resolution) and two ligand-bound structures of P46 with maltose (2.5 Å resolution) and xylose (3.5 Å resolution) in open and closed conformations, respectively. The ligand-binding site is buried in the cleft between the domains at the hinge region. The two domains of P46 can rotate with respect to each other, giving open or closed alternative conformations. In agreement with this structural information, sequence analyses show similarities to substrate-binding members of the ABC transporter superfamily, with P46 facing the extracellular side as a functional subunit. In the structure with xylose, P46 was also bound to a high-affinity (Kd= 29 nM) Fab fragment from a monoclonal antibody, allowing the characterization of a structural epitope in P46 that exclusively involves residues from the C-terminal domain. The Fab structure in the complex with P46 shows only small conformational rearrangements in the six complementarity-determining regions (CDRs) with respect to the unbound Fab (the structure of which is also determined in this work at 1.95 Å resolution). The structural information that is now available should contribute to a better understanding of sugar nutrient intake byM. hyopneumoniae. This information will also allow the design of protocols and strategies for the generation of new vaccines against this important swine pathogen.
Capitalising teamwork for enhancing project delivery and management in construction: empirical study in Malaysia
Authors: Yap Jeffrey Boon Hui , Leong Wen Jie , Skitmore Martin
Published: April 2020

Purpose

Teamwork in the construction industry has attracted much attention from both academic and industrial circles. Most importantly, improving team effectiveness will increase the likelihood of successful project delivery. Recognising the factors influencing team dynamics is important for enhanced team performance.

Design/methodology/approach

Based on a detailed literature review, a survey questionnaire containing 10 aspects and 25 attributes of teamwork relevant to construction is used to collect feedback from Malaysian construction practitioners from client, consultant and contractor organisations to prioritise these hypothesised variables. The data are then subjected to reliability analysis, descriptive statistics (means, standard deviations, and frequencies), a one-sample t-test, the Kruskal–Wallis ANOVA and exploratory factor analysis.

Findings

The significance of these aspects and attributes is then presented. The three most crucial aspects are “project performance”, “decision-making capability” and “problem-solving ability”. The most influential attributes are “effective communication between project team members”, “efficient team leadership”, “well-defined team responsibilities and roles”, “clear team goals and objectives” and “good collaboration between all project leaders”. The Kruskal–Wallis ANOVA reveals five attributes having statistically significant differences with respect to company size, namely “clear team goals and objectives”, “commitment to the project”, “adequate resources”, “team or task processes” and “creativity and innovation”. Six underlying dimensions are found, comprising (1) participative engagement and task commitment; (2) team responsibility structure and accountability; (3) culture of trust and respect; (4) leader's skills and abilities; (5) top management support; and (6) synergic working environment.

Practical implications

The identification of these dimensions for team effectiveness provides rigorous basis for formulating useful team-building strategies for integrating a collaborative environment among project stakeholders and consequently improving project performance.

Originality/value

This paper bridges the identified knowledge gap concerning the dimensionality of teamwork attributes in construction-based setting and adds to existing knowledge of how team effectiveness can be leveraged to improve project performance in the construction management literature.
Corporate social responsibility disclosure and firms' performance in Mediterranean countries: a stakeholders' perspective
Authors: Buallay Amina , Kukreja Gagan , Aldhaen Esra , Al Mubarak Muneer , Hamdan Allam Mohammed
Published: April 2020

Purpose

The purpose of this study is to investigate the relationship between corporate social responsibility (CSR) disclosure and firms' operational, financial and market performance (measured in the form of return on assets (ROA), return on equity (ROE) and Tobin's Q (TQ), respectively) in the Mediterranean countries from a stakeholder perspective.

Design/methodology/approach

Research is quantitative in nature, based on a cross-sectional and time-series analysis of 203 firms listed in six Mediterranean countries for 10 years from 2008 to 2017, with 1,689 observations. The theoretical model is built on a stakeholder theory. The practical model is built on the independent variable (CSR) and the dependent variables ROA, ROE and TQ.

Findings

The findings deduced from the empirical results indicated that CSR disclosure negatively affects operational and market performance but does not affect financial performance.

Practical implications

Studying the relationship between CSR disclosure and firms' operational, financial and market performance, with the consideration of variations, can bring many benefits internally by being more conscious of important activities that should be undertaken and externally by detecting what regulators and other stakeholders want for better sustainable development.

Originality/value

This research adds value to the existing limited literature of CSR disclosure on firm's performance in the Mediterranean countries, and it gives tips of advice for firms to manage CSR disclosure wisely.
How live chat assistants drive travel consumers’ attitudes, trust and purchase intentions
Authors: McLean Graeme , Osei-Frimpong Kofi , Wilson Alan , Pitardi Valentina
Published: April 2020

Purpose

By adopting a social presence theory perspective, this study aims investigate the influence of perceived usefulness of live chat services and of their unique human attributes on customer attitudes, beliefs and behaviours in the context of online travel shopping.

Design/methodology/approach

Based on a cross-sectional survey research involving 8 travel provider websites and 631 travel consumers, this work applies structural equation modelling to analyse the data.

Findings

The results illustrate that the perceived usefulness from the communication with a human live chat assistant positively influences customer attitudes and trust towards the website as well as increasing purchase intention. The findings further illustrate the role of the human social cues conveyed by live chat facilities, namely, human warmth, human assurance, human attentiveness and human customised content in positively moderating this effect.

Research limitations/implications

The study is limited to specific human attributes. Future research could investigate the role of other human characteristics as well as assess the ability of artificial intelligent powered chatbots in replicating the human elements outlined in this research.

Originality/value

The study provides a unique contribution to the travel literature by offering empirical insights and conceptual clarity into the usefulness of human operated live chat communication on travellers’ attitudes, trust towards the website and purchase intentions.
Winescape through the lens of organized travel – a netnography study
Authors: Terziyska Ilinka , Damyanova Radina
Published: April 2020

Purpose

Winescape is the space where wine experiences occur, consisting of both tangible and intangible elements, and its understanding is very important for both the wine and the tourism industry. The purpose of this study is to define the attributes of winescape as seen from the perspective of organized travel.

Design/methodology/approach

The study uses the netnography approach by analyzing online user-generated content. A total of 118 TripAdvisor reviews for a wine tour company in Piemont, Italy, were coded using NVIVO12 software.

Findings

Six major elements of winescape were identified: tour guiding, core wine product, tour planning and logistics, complementary activities, food and dining and nature and scenery prominent. When compared to previous research, the findings show that the type of travel (organized versus independent travel) has a significant impact on the perceived winescape.

Research limitations/implications

As the study refers to a particular type of destination (Piedmont, Italy), and a specific product (private or small group tours), findings may not fully apply to wine regions and market segments of a different kind.

Practical implications

The proposed winescape model can be used by both practitioners (for enhancing the quality of their products) and researchers (for comparative studies or as a basis for customer satisfaction models specifically tailored to wine tours).

Originality/value

Organized wine tours as a specific aspect of wine tourism have been neglected in research so far. To the authors’ knowledge, this is the first study to focus on winescape as seen through the lens of organized wine tourists, and the resulting model differs significantly from the existing ones.
Subjective well-being among victimized university students: comparison between cyber dating abuse and bullying victimization
Authors: Víllora Beatriz , Yubero Santiago , Navarro Raul
Published: April 2020

Purpose

Previous research has documented a negative association between subjective well-being and different forms of victimization. The present study aims to examine differences in well-being among university student victims of cyber dating abuse and bullying after controlling for acceptance of dating violence.

Design/methodology

This a cross-sectional study involving 1,657 Spanish university students (62.1% females, 37.1% males) using a quantitative approach.

Findings

The multiple regression analysis results showed that the university students who reported low bullying victimization and low acceptance of dating violence also reported higher emotional, social and psychological well-being, although the association between bullying and well-being was weak. No relationship was found between cyber dating abuse victimization and the well-being dimensions examined (emotional, social and psychological). Indeed, the participants not involved in any form of abuse and the cyber dating abuse victims presented the highest level of emotional, social and psychological well-being compared to the bullying victims and the combined victims.

Practical implications

Prevention and intervention programs need to specifically address bullying and cyber dating abusive in university, with a special focus on normative beliefs about both types of victimization and offering different sources of support to overcome negative consequences on mental health.

Originality/value

This paper analyzes the subjective well-being correlates simultaneously in victims of cyber dating abuse and bullying among university students without assuming that every form of victimization has the same mental health outcomes.
Labor division and advantages and limits of participation in creation of intangible assets in industry 4.0: humans versus machines
Authors: Lobova Svetlana V. , Alekseev Alexander N. , Litvinova Tatiana N. , Sadovnikova Natalia A.
Published: April 2020

Purpose

The purpose of the work is to solve the set problem and to study the competition and perspectives of division of labor of humans and machines during creation of intangible assets in Industry 4.0.

Design/methodology/approach

The research is performed with the help of regression and comparative analysis by building regression curves and with the help of the qualitative structural and logical analysis.

Findings

The authors perform an overview of the factors that determine the advantages and limits of participation in creation of intangible assets in Industry 4.0, determine the perspectives and compile recommendations for division of human and machine labor during creation of intangible assets in Industry 4.0.

Originality/value

The results of the performed research confirmed the general hypothesis that machine technologies allow improving the innovative, marketing and organizational and managerial activities and activities in the sphere of R&D through automatization of certain stages of the process of creation of intangible assets. The authors determine the factors that define the contribution of machine technologies in this process and their competitive advantages as compared to human intellectual capital during creation of intangible assets. These advantages prove the possibility and expedience of division of human and machine labor during creation of intangible assets.
The relationship between abusive supervision and unethical pro-organizational behavior: linear or curvilinear?
Authors: Guo Limin , Zhao Hongdan , Cheng Ken , Luo Jinlian
Published: April 2020

Purpose

Based on social exchange theory and research on proactive personality, this study aims to explore the relationship between abusive supervision and unethical pro-organizational behavior (UPB), taking proactive personality as a boundary condition.

Design/methodology/approach

This study conducted a two-wave questionnaire survey and used data from 353 Chinese employees of a diversified company to test the research hypotheses.

Findings

The relationship between abusive supervision and UPB varied with proactive personality. Specifically, abusive supervision had an inverted U-shaped effect on UPB when proactive personality was high, while abusive supervision was negatively related to UPB when proactive personality was low.

Research limitations/implications

More research are encouraged to replicate our study in different cultural contexts. Besides, future research can gather data from dyads (e.g. supervisor–subordinate dyad and coworker–subordinate dyad) so as to increase the objectivity and validity of the data.

Practical implications

Managers should reduce abusive supervision and elevate proactive employees' moral awareness.

Social implications

This study hopes that the authors’ findings will help practitioners to devote greater attention to managing proactive personality, abusive supervision and UPB in the organization.

Originality/value

First, this study enriches the abusive supervision literature by identifying UPB as a consequence of abusive supervision. Second, this study provides a better understanding of the coping tactics used to combat abusive supervision. Third, this study uncovers a dark side of proactive personality by verifying the moderating effect of proactive personality.
Internationalisation theory and Born Globals
Authors: Wadeson Nigel
Published: April 2020

Purpose

It has been claimed that Born Globals are incompatible with the Uppsala model, which is based on the firm having a maximum tolerable risk level. This assumption was used to explain observed incremental commitments, with further commitments being made as experiential learning reduces the level of risk faced. This study aims to show that adding a consideration of the role of expected value, including the effects of resource constraints, can reconcile the Born Global and internationalisation process literatures.

Design/methodology/approach

The theoretical arguments are supported by mathematical modelling of a firm pursuing expected value based on subjective beliefs.

Findings

While the effects of risk and expected value coincide when firms limit their downside risks by taking an incremental approach to commitments, other factors impacting on expected value can shift the balance of incentives towards earlier and more rapid internationalisation. For instance, some firms are specialised and have high costs of R&D, and so need to achieve early and rapid growth but face small home markets. While resource constraints can lead a firm to expand for some time in its home market before internationalising, the effect can be reversed in the case of the finance constraint for some firms.

Originality/value

The study shows how Born Global and internationalisation process literatures can be reconciled through a consideration of the effects of expected value on internationalisation decisions. It also provides a novel theoretical analysis of Born Globals.