bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maturation Trajectories of Cortical Resting-State Networks Depend on the Mediating Frequency Band
Authors: Khan S. , Hashmi J. A. , Mamashli F. , Michmizos K. , Kitzbichler M. G. , Bharadwaj H. , Bekhti Y. , Ganesan S. , Garel K. A , Whitfield-Gabrieli S. , Gollub R. L. , Kong J. , Vaina L. M. , Rana K. D. , Stufflebeam S. S. , Hämäläinen M. S. , Kenet T. 
Published: February 2018

ABSTRACTThe functional significance of resting state networks and their abnormal manifestations in psychiatric disorders are firmly established, as is the importance of the cortical rhythms in mediating these networks. Resting state networks are known to undergo substantial reorganization from childhood to adulthood, but whether distinct cortical rhythms, which are generated by separable neural mechanisms and are often manifested abnormally in psychiatric conditions, mediate maturation differentially, remains unknown. Using magnetoencephalography (MEG) to map frequency band specific maturation of resting state networks from age 7 to 29 in 162 participants (31 independent), we found significant changes with age in networks mediated by the beta (13-30Hz) and gamma (31-80Hz) bands. More specifically, gamma band mediated networks followed an expected asymptotic trajectory, but beta band mediated networks followed a linear trajectory. Network integration increased with age in gamma band mediated networks, while local segregation increased with age in beta band mediated networks. Spatially, the hubs that changed in importance with age in the beta band mediated networks had relatively little overlap with those that showed the greatest changes in the gamma band mediated networks. These findings are relevant for our understanding of the neural mechanisms of cortical maturation, in both typical and atypical development.
Representation of multiple objects in macaque category-selective areas
Authors: Bao Pinglei , Tsao Doris Y. 
Published: February 2018

AbstractObject recognition in the natural world usually occurs in the presence of multiple surrounding objects, but responses of neurons in inferotemporal (IT) cortex, the large brain area responsible for object recognition, have mostly been studied only to isolated objects. We study rules governing responses to multiple objects by cells in two category-selective regions of macaque IT cortex, the middle lateral face patch (ML) and the middle body patch (MB). We find that responses of single ML and MB cells to pairs of objects could be explained by the widely-accepted framework of normalization, with one added ingredient: homogeneous category selectivity of neighboring neurons forming the normalization pool. This rule leads to winner-take-all, contralateral-take-all, or weighted averaging behavior in single cells, depending on the category, spatial configuration, and relative contrast of the two objects. The winner-take-all behavior suggests a potential mechanism for clutter-invariant representation of face and bodies under certain conditions.
A widespread decrease of chromatin accessibility in age-related macular degeneration
Authors: Wang Jie , Zibetti Cristina , Shang Peng , Sripathi Srinivasa R. , Zhang Pingwu , Cano Marisol , Hoang Thanh , Xia Shuli , Ji Hongkai , Merbs Shannath L. , Zack Donald J. , Handa James T. , Sinha Debasish , Blackshaw Seth , Qian Jiang 
Published: February 2018

AbstractAge-related macular degeneration (AMD) is a leading cause of blindness in the elderly. The extent to which epigenetic changes regulate AMD progression is unclear. Here we globally profiled chromatin accessibility in the retina and retinal pigmented epithelium (RPE) from AMD patients and controls. Global decreases in chromatin accessibility occurr in RPE in early AMD, and in the retina with advanced disease, suggesting that dysfunction in RPE cells drives disease progression. Footprints of photoreceptor and RPE-specific transcription factors are enriched in differentially accessible regions (DARs). Genes associated with DARs show altered expression in AMD. Cigarette smoke treatment of RPE cells recapitulates epigenomic changes seen in AMD, providing an epigenetic link between the known risk factors for AMD and AMD pathology. Finally, overexpression of HDAC11 is partially responsible for the reduction in chromatin accessibility, identifying potential new targets for treatment of AMD.
Competition in biofilms between cystic fibrosis isolates ofPseudomonas aeruginosais shaped by R-pyocins
Authors: Oluyombo Olubukola , Penfold Christopher N. , Diggle Stephen P. 
Published: February 2018

ABSTRACTPseudomonas aeruginosais an opportunistic pathogen responsible for a number of different human infections and is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients.P. aeruginosainfections are difficult to treat due to a number of antibiotic resistance mechanisms and the organisms propensity to form multicellular biofilms. Epidemic strains ofP. aeruginosaoften dominate within the lungs of individual CF patients, but how they achieve this is poorly understood. One of the ways strains ofP. aeruginosacan compete, is by producing chromosomally encoded bacteriocins, called pyocins. Three major classes of pyocin have been identified inP. aeruginosa:soluble pyocins (S-types) and tailocins (R- and F-types). In this study, we investigated the distribution of S- and R-type pyocins in 24 clinical strains isolated from individual CF patients and then focused on understanding their roles on inter-strain competition. We found that (i) each strain produced only one R-pyocin type, but the number of S-pyocins varied between strains; (ii) R-pyocins were generally important for strain dominance during competition assays in planktonic cultures and biofilm communities in strains with both disparate R and S pyocin sub-types. (iii) purified R-pyocins demonstrated significant antimicrobial activity against established biofilms. Our work provides support for a key role played by R-pyocins in the competition betweenP. aeruginosastrains, and may help explain why certain strains and lineages ofP. aeruginosadominate and displace others during CF lung infection. Furthermore, we demonstrate the potential of exploiting R-pyocins for therapeutic gains in an era when antibiotic resistance is a global concern.IMPORTANCEA major clinical problem caused byPseudomonas aeruginosa, is chronic biofilm infection of the lungs in individuals with cystic fibrosis (CF). EpidemicP. aeruginosastrains dominate and displace others during CF infection, but these intra-species interactions remain poorly understood. Here we demonstrate that R-pyocins (bacterocins) are important factors in driving competitive interactions in biofilms betweenP. aeruginosastrains isolated from different CF patients. In addition, we found that these phage-like pyocins are inhibitory against mature biofilms of susceptible strains. This highlights the potential of R-pyocins as antimicrobial and antibiofilm agents, at a time when new antimicrobial therapies are desperately needed.
CRISPR Cas9 searches for a protospacer adjacent motif by one-dimensional diffusion
Authors: Globyte Viktorija , Lee Seung Hwan , Bae Taegun , Kim Jin-Soo , Joo Chirlmin 
Published: February 2018

AbstractSince its discovery, the CRISPR/Cas9 system has been at the focus of fundamental researchers, genome engineers, and the general public alike. Despite being in the spotlight for several years, aspects of the precise molecular mechanism of Cas9 activity remain ambiguous. We use single-molecule Foerster resonance energy transfer (smFRET) to reveal Cas9 target search mechanism with nanometer sensitivity. We have developed single-molecule assays to monitor transient interactions of Cas9 and DNA in real time. Our study shows that Cas9 interacts with the protospacer adjacent motif (PAM) sequence weakly, yet probing neighboring sequences via lateral diffusion. This dynamic mode of interactions leads to translocation of Cas9 to another PAM nearby and consequently an on-target sequence. We propose a model in which lateral diffusion competes with 3-dimensional diffusion and thus might aid PAM finding and consequently on-target binding.
A plant biodiversity effect resolved to a single genetic locus
Authors: Wuest Samuel E. , Niklaus Pascal A. 
Published: February 2018

SummaryDespite extensive evidence that biodiversity promotes plant community productivity, progress towards understanding the mechanistic basis of this effect remains slow, impeding the development of predictive ecological theory and agricultural applications. Here, we analysed non-additive interactions between genetically divergent Arabidopsis accessions in experimental plant communities. By combining methods from ecology and genetics, we identified a major effect locus at which allelic differences between individuals increases above-ground productivity of communities. In experiments with near-isogenic lines, we show that this diversity effect acts independently of other genomic regions and can be resolved to a single region representing less than 0.3% of the genome. Using plant-soil-feedback experiments, we also demonstrate that allelic diversity causes genotype-specific soil legacy responses in a consecutive growing period, even after the original community has disappeared. Our work thus suggests that positive diversity effects can be linked to single Mendelian factors, and that a range of complex community properties can have a simple cause. This may pave the way to a better understanding of diversity effects, and to novel breeding strategies, focussing on phenotypic properties that manifest themselves beyond isolated individuals, i.e. at a higher level of biological organisation.
Axenic Aedesaegyptidevelop without live bacteria, but exhibit delayed development and reduced oviposition
Authors: Correa Maria A. , Brackney Doug E , Steven Blaire 
Published: February 2018

AbstractThe mosquito gut microbiome plays an important role in mosquito development and fitness, providing a promising avenue for novel mosquito control strategies. Here we present a method for rearing axenic (bacteria free)Aedes aegyptimosquitoes, which will greatly facilitate mechanistic studies documenting the structure and function of the microbiome. Through feeding sterilized larvae agar plugs containing attenuatedEscherichia coli, mosquito development was observed in the absence of living bacteria. Axenic larvae were capable of full development into adults, which laid eggs that were subsequently hatched. However, axenic mosquitoes exhibited delayed development time and reduced egg clutch size in comparison to bacterially colonized mosquitoes. These findings suggest that mosquito development is not dependent on live bacteria, but their phenotype is modulated by the presence of microorganisms. This axenic system offers a new tool in which the mosquito microbiome can be systematically manipulated for a deeper understanding of microbiome host interactions.
F-actin patches nucleated on chromosomes coordinate capture by microtubules in oocyte meiosis
Authors: Burdyniuk Mariia , Callegari Andrea , Mori Masashi , Nédélec François , Lénárt Péter 
Published: February 2018

AbstractCapture of each and every chromosome by spindle microtubules is essential to prevent chromosome loss and aneuploidy. In somatic cells, astral microtubules search and capture chromosomes forming lateral attachments to kinetochores. However, this mechanism alone is insufficient in large oocytes. We have previously shown that a contractile F-actin network is additionally required to collect chromosomes scattered in the 70-μm starfish oocyte nucleus. How this F-actin-driven mechanism is coordinated with microtubule capture remained unknown. Here, we show that after nuclear envelope breakdown Arp2/3-nucleated F-actin patches form around chromosomes in a Ran-GTP-dependent manner, and we propose that these structures sterically block kinetochore-microtubule attachments. Once F-actin-driven chromosome transport is complete, coordinated disassembly of these F-actin patches allows synchronous capture by microtubules. Our observations indicate that this coordination is necessary, as early capture of chromosomes by microtubules would interfere with F-actin-driven transport leading to chromosome loss and formation of aneuploid eggs.
Saccharomyces cerevisiaehistone Chaperones FACT and Spt6 modulate Pol II and histone occupancy genome-wide
Authors: Pathak Rakesh , Singh Priyanka , Ananthakrishnan Sudha , Adamczyk Sarah , Schimmel Olivia , Govind Chhabi K. 
Published: February 2018

ABSTRACTHistone chaperones, chromatin remodelers, and histone modifying complexes play a critical role in alleviating the nucleosomal barrier. Here, we have examined the role of two highly conserved yeast (Saccharomyces cerevisiae) histone chaperones, FACT and Spt6, in regulating transcription and histone occupancy. We show that the H3 tail contributes to the recruitment of FACT to coding sequences in a manner dependent on acetylation. We found that deleting a H3 HAT Gcn5 or mutating lysines on the H3 tail impairs FACT recruitment atADH1andARG1genes. However, deleting the H4 tail or mutating the H4 lysines failed to dampen FACT occupancy in coding regions. Additionally, we show that FACT-depletion greatly reduces Pol II occupancy in the 5’ ends genome-wide. By contrast, Spt6-depletion led to reduction in Pol II occupancy towards the 3’ end, in a manner dependent on the gene-length. Severe transcription and histone eviction defects were also observed in a strain that was impaired for Spt6 recruitment (spt6Δ202) and depleted of FACT. Importantly, the severity of the defect strongly correlated with WT Pol II occupancies at these genes, indicating critical roles of Spt6 and Spt16 in promoting high-level transcription. Collectively, our study shows cooperation, as well as redundancy between chaperones, FACT and Spt6, in regulating transcription and chromatin in coding regions of transcribed genes.
Water availability dynamics have long-term effects on mature stem structure in Vitis vinifera
Authors: Munitz S. , Netzer Y. , Shtein Ilana , Schwartz A. 
Published: February 2018

AbstractVitis vinifera is a climbing vine with wide vessels and high hydraulic conductivity. There is a lack of data on the anatomical structure of the mature vine stem, and most current knowledge is based on first-year shoots. Moreover, the effect of drought stress on anatomical structure has been partly reported in shoots of Vitis vinifera but not in stems.In current study two irrigation approaches were applied on Vitis vinifera Merlot vines: constant (low, medium and high irrigation) and dynamic (early/late season water deficit). The following parameters were measured: trunk diameter, annual ring width and area, vessel diameter, specific hydraulic conductivity and stem water potential.High water availability early in the season (high irrigation and late deficit) resulted in vigorous vegetative growth (greater trunk diameter, ring width and area), wider vessels and increased specific hydraulic conductivity. The distribution of large xylem vessels was altered by drought stress, where high water availability early in the season caused a shift of the vessel population towards the wider frequency classes. Interestingly, the early deficit vines showed more negative water potential values late in the season compared to the low irrigation vines. This may imply an effect of anatomical structure on vine water status.HighlightsWater availability early in the season determines vegetative growth and stem anatomical structure in mature Vitis vinifera vines.
Intellectual stimulation and team creative climate in a professional service firm
Authors: Sandvik Alexander Madsen , Croucher Richard , Espedal Bjarne , Selart Marcus 
Published: February 2018

PurposeThe purpose of this paper is to investigate the precise role of intrinsic motivation and autonomy in relation to intellectual stimulation in creating a creative climate in a professional services firm. The intention is to discover whether theories that stress the primacy of the need for intrinsic motivation and autonomy over other managerial goals such as monitoring find support.Design/methodology/approachThe authors propose and test a model for the relationship of interest. The theoretical model is tested through analysis of multilevel data gathered across in two iterations over two years from 177 employees and 64 teams in one company.FindingsThe authors find that intrinsic motivation and autonomy mediate the relationship between intellectual stimulation and creative climate. Autonomy exercises a stronger mediating effect than intrinsic motivation.Research limitations/implicationsThe single company research context’s specificity; causal relationships between variables cannot be empirically investigated; the verified research model cannot claim to represent how the organization actually functions, for which qualitative work is required.Practical implicationsTheories stressing the primacy of employee autonomy are supported over those stressing a need for management to monitor and control autonomy-seeking employees.Originality/valueThis paper shows the vital mediating role of employee autonomy and to a lesser extent intrinsic motivation in a professional service firm context.
Empowering leadership and organizational ambidexterity: a moderated mediation model
Authors: Siachou Evangelia , Gkorezis Panagiotis 
Published: February 2018

PurposeThe purpose of this paper is to examine the effect of empowering leadership on contextual ambidexterity. To this end, the authors underscore the underlying mechanism of perceived organizational support (POS). Furthermore, to provide more robust insights into this indirect effect, role ambiguity was examined as a moderator.Design/methodology/approachThe paper is based on a questionnaire survey. Data collected from 219 employees working in three IT small-and-medium enterprises located in Greece.FindingsThe findings indicated that empowering leadership is positively related to contextual ambidexterity through POS and, further, this indirect association is contingent on role ambiguity.Originality/valueThe study provides more insights into the important role of leadership in generating contextual ambidexterity. Thus, moderated mediation framework that has empirically tested considers both how and when empowering leadership affects contextual ambidexterity and provides important implications for both theory and practice.
Modeling the determinants of turnover intentions: a Bayesian approach
Authors: Nandialath Anup Menon , David Emily , Das Diya , Mohan Ramesh 
Published: February 2018

PurposeMuch of what we learn from empirical research is based on a specific empirical model(s) presented in the literature. However, the range of plausible models given the data is potentially larger, thus creating an additional source of uncertainty termed: model uncertainty. The purpose of this paper is to examine the effect of model uncertainty on empirical research in HRM and suggest potential solutions to deal with the same.Design/methodology/approachUsing a sample of call center employees from India, the authors test the robustness of predictors of intention to leave based on the unfolding model proposed by Harmanet.al.(2007). Methodologically, the authors use Bayesian Model Averaging (BMA) to identify the specific variables within the unfolding model that have a robust relationship with turnover intentions after accounting for model uncertainty.FindingsThe findings show that indeed model uncertainty can impact what we learn from empirical studies. More specifically, in the context of the sample, using four plausible model specifications, the authors show that the conclusions can vary depending on which model the authors choose to interpret. Furthermore, using BMA, the authors find that only two variables, job satisfaction and perceived organizational support, are model specification independent robust predictors of intention to leave.Practical implicationsThe research has specific implications for the development of HR analytics and informs managers on which are the most robust elements affecting attrition.Originality/valueWhile empirical research typically acknowledges and corrects for the presence of sampling uncertainty throughp-values, rarely does it acknowledge the presence of model uncertainty (which variables to include in a model). To the best of the authors’ knowledge, it is the first study to show the effect and offer a solution to studying total uncertainty (sampling uncertainty + model uncertainty) on empirical research in HRM. The work should open more doors toward more studies evaluating the robustness of key HRM constructs in explaining important work-related outcomes.
Globalisation and governance in Africa: a critical contribution to the empirics
Authors: Asongu Simplice A. , Efobi Uchenna , Tchamyou Vanessa S. 
Published: February 2018

Purpose
This study aims to assess the effect of globalisation on governance in 51 African countries for the period 1996-2011.

Design/methodology/approach
Ten bundled and unbundled governance indicators and four globalisation variables are used. The empirical evidence is based on Generalised Method of Moments.

Findings
Firstly, on political governance, while only social globalisation improves political stability, only economic globalisation does not increase voice and accountability and political governance. Secondly, with regard to economic governance: only economic globalisation significantly promotes regulation quality; social globalisation and general globalisation significantly advance government effectiveness; and economic globalisation and general globalisation significantly promote economic governance. Thirdly, with respect to institutional governance, while only social globalisation improves corruption-control, the effects of globalisation dynamics on the rule of law and institutional governance are not significant. Fourthly, the impacts of social globalisation and general globalisation are positive on general governance.

Practical implications
It follows that political governance is driven by voice and accountability compared to political stability; economic governance is promoted by both regulation quality and government effectiveness from specific globalisation angles; and globalisation does not improve institutional governance for the most part.

Originality/value
Governance variables are bundled and unbundled to reflect evolving conceptions and definitions of governance. Theoretical contributions and policy implications are discussed.