bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Rac1 pools integrate the direction and coordination of collective cell migration
Authors: Zhou Sijia , Li Peng , Liu Jiaying , Li Hao , Liao Juan , Chen Lin , Yi Bin , Wang Xiaobo 
Published: June 2022

AbstractIntegration of collective cell direction and coordination is believed to ensure collective guidance for efficient movement. Previous studies demonstrated that chemokine receptors PVR and EGFR govern a gradient of Rac1 activity essential for collective guidance of Drosophila border cells, whose mechanistic insight is unknown. By monitoring and manipulating subcellular Rac1 activity, here we reveal two switchable Rac1 pools at border cell protrusions and supracellular cables, two important structures responsible for direction and coordination. Rac1 and Rho1 form a positive feedback loop that guides mechanical coupling at cables to achieve migration coordination. Rac1 cooperates with Cdc42 to control protrusion growth for migration direction, as well as to regulate the protrusion-cable exchange, linking direction and coordination. PVR and EGFR guide correct Rac1 activity distribution at protrusions and cables. Therefore, our studies emphasize the existence of a balance between two Rac1 pools, rather than a Rac1 activity gradient, as an integrator for the direction and coordination of collective cell migration.
B-Myb association with DNA is mediated by its negative regulatory domain and Cdk phosphorylation
Authors: Wijeratne Tilini U. , Guiley Keelan Z. , Lee Hsiau-Wei , Müller Gerd A. , Rubin Seth M. 
Published: June 2022

AbstractB-Myb is a highly conserved member of the vertebrate Myb family of transcription factors that plays a critical role in cell-cycle progression and proliferation. Myb proteins activate Myb-dependent promoters by interacting specifically with Myb binding site (MBS) sequences using their DNA binding domain (DBD). Transactivation of MBS promoters by B-Myb is repressed by its negative regulatory domain (NRD), and phosphorylation of the NRD by Cdk2-CyclinA relieves the repression to activate B-Myb dependent promoters. The structural mechanisms underlying autoinhibition and activation have been poorly characterized. We determined that a region in the B-Myb NRD (residues 510-600) directly associates with the DBD and inhibits DBD binding to the MBS DNA sequence. We demonstrate that phosphorylation of the NRD at T515, T518, and T520 is sufficient to disrupt the interaction between the NRD and the DBD, which results in increased affinity for MBS DNA and increased B-Myb-dependent promoter activation. Our biochemical characterization of B-Myb autoregulation and the activating effects of phosphorylation provides insight into how B-Myb functions as a site-specific transcription factor.
Rapid and reversible optogenetic silencing of synaptic transmission by clustering of synaptic vesicles
Authors: Vettkötter Dennis , Schneider Martin , Liewald Jana , Zeiler Sandra , Guldan Julia , Watanabe Shigeki , Gottschalk Alexander 
Published: June 2022

AbstractSilencing neurons acutely and specifically informs about their functional roles in circuits and behavior. Existing optogenetic silencers include ion pumps or channels, and tools that damage the neurotransmitter release machinery. While the former hyperpolarize the cell and can alter ionic gradients, the latter allow only slow recovery, requiring de novo synthesis. Thus, there is a need for other strategies combining fast activation and reversibility. Here, we use light-evoked homo-oligomerization of cryptochrome CRY2 to silence synaptic transmission, by clustering synaptic vesicles (SVs). We benchmark this tool, optoSynC, by electrophysiology and locomotion in Caenorhabditis elegans. optoSynC clusters SVs within 25 s, causing approximation, observable by electron microscopy. Locomotion silencing is rapid (tauon ∼15 s) and recovers quickly (tauoff ∼10 min) after light-off. Further, optoSynC can inhibit exocytosis for several hours, at very low light intensities. optoSynC is a highly efficient, ‘non-ionic’ optogenetic silencer that may further allow to manipulate different SV pools.
Defocus Corrected Large Area Cryo-EM (DeCo-LACE) for Label-Free Detection of Molecules across Entire Cell Sections
Authors: Elferich Johannes , Schiroli Giulia , Scadden David , Grigorieff Nikolaus 
Published: June 2022

AbstractA major goal of biological imaging is localization of biomolecules inside a cell. Fluorescence microscopy can lo-calize biomolecules inside whole cells and tissues, but its ability to count biomolecules and accuracy of the spatial coordinates is limited by the wavelength of visible light. Cryo-electron microscopy (cryo-EM) provides highly accurate position and orientation information of biomolecules but is often confined to small fields of view inside a cell, limiting biological context. In this study we use a new data-acquisition scheme called “Defocus-Corrected Large-Area cryo-EM” (DeCo-LACE) to collect high-resolution images of entire sections (100 – 200 nm thick lamel-lae) of neutrophil-like mouse cells, representing 1-2% of the total cellular volume. We use 2D template matching (2DTM) to determine localization and orientation of the large ribosomal subunit in these sections. These data provide “maps” of ribosomes across entire sections of mammalian cells. This high-throughput cryo-EM data collection approach together with 2DTM will advance visual proteomics and provide biological insight that cannot be obtained by other methods.
Immediate early proteins of herpes simplex virus transiently repress viral transcription before subsequent activation
Authors: Dunn Laura E.M. , Birkenheuer Claire H. , Dufour Rachel , Baines Joel D. 
Published: June 2022

AbstractHerpes simplex virus 1 (HSV-1) utilizes cellular RNA polymerase II (Pol) to transcribe its genes in one of two phases. In the latent phase, viral transcription is highly restricted but during the productive lytic phase, more than 80 genes are expressed in a temporally coordinated cascade. In this study, we used precision nuclear Run On followed by deep Sequencing (PRO-Seq) to characterize early viral transcriptional events using HSV-1 immediate early (IE) gene mutants, corresponding genetically repaired viruses, and wild type virus. Unexpectedly, in the absence of the IE genes ICP4, ICP22 or ICP0 at 1.5 hpi we observed high levels of aberrant transcriptional activity across the mutant viral genomes, but substantially less on either wild type or the congenic repaired virus genomes. This feature was particularly prominent in the absence of ICP4 expression. Cycloheximide treatment during infection with both the ICP4 and ICP22 mutants and their respective genetic repairs did not alter the relative distribution of Pol activity, but increased overall activity across both viral genomes, indicating that both virion components and at least some de novo protein synthesis were required for full repression. Overall, these data reveal that prior to their role in transcriptional activation, IE gene products and virion components first repress transcription and that the HSV-1 lytic transcriptional cascade is mediated through subsequent de-repression steps.ImportanceHerpes simplex virus 1 (HSV-1) transcription during productive replication is believed to comprise a series of activation steps leading to a specific sequence of gene expression. Here we show that virion components and immediate early (IE) gene products ICP0, ICP4 and ICP22 first repress viral gene transcription to varying degrees before subsequently activating specific gene subsets. It follows that the entire HSV transcriptional program involves a series of steps to sequentially reverse this repression. This previously uncharacterized repressive activity of IE genes very early in infection may represent an important checkpoint allowing HSV-1 to orchestrate either the robust lytic transcriptional cascade or the more restricted transcriptional program during latency.
Juvenile Shank3 KO mice adopt distinct hunting strategies during prey capture learning
Authors: Kuhnle Chelsea Groves , Grimes Micaela , Casanova Victor Manuel Suárez , Turrigiano Gina G. , Van Hooser Stephen D. 
Published: June 2022

AbstractMice are opportunistic omnivores that readily learn to hunt and eat insects such as crickets. The details of how mice learn these behaviors and how these behaviors may differ in strains with altered neuroplasticity are unclear. We quantified the behavior of juvenile wild type and Shank3 knockout mice as they learned to hunt crickets during the critical period for ocular dominance plasticity. This stage involves heightened cortical plasticity including homeostatic synaptic scaling, which requires Shank3, a glutamatergic synaptic protein that, when mutated, produces Phelan-McDermid syndrome and is often comorbid with autism spectrum disorder (ASD). Both strains showed interest in examining live and dead crickets and learned to hunt. Shank 3 knockout mice took longer to become proficient, and, after 5 days, did not achieve the efficiency of wild type mice in either time-to-capture or distance-to-capture. Shank3 knockout mice also exhibited different characteristics when pursuing crickets that defied explanation as a simple motor deficit. Although both genotypes moved at the same average speed when approaching a cricket, Shank3 KO mice paused more often during approaches, did not begin final accelerations toward crickets as early, and did not close the distance gap to the cricket as quickly as wild type mice. These differences in Shank3 KO mice are reminiscent of some behavioral characteristics of individuals with ASD as they perform complex tasks, such as slower action initiation and completion. This paradigm will be useful for exploring the neural circuit mechanisms that underlie these learning and performance differences in monogenic ASD rodent models.
Kinetic Characterization and Computational Modeling of the Escherichia coli Heptosyltransferase II: Exploring the Role of Protein Dynamics in Catalysis for a GT-B Glycosyltransferase
Authors: Hassan Bakar A. , Liu Zhiqi A. , Milicaj Jozafina , Kim Mia S. , Tyson Meka , Sham Yuk Y. , Taylor Erika A. 
Published: June 2022

AbstractGlycosyltransferases (GTs) are enzymes that are uniquely adapted to promote the formation of a glycosidic bond between a sugar molecule and a wide variety of substrates. Heptosyltransferase II (HepII) is a GT involved in the lipopolysaccharide (LPS) biosynthetic pathway that transfers the seven-carbon sugar (L-glycero-D-manno-heptose; Hep) onto a lipid anchored glycopolymer (heptosylated Kdo2-Lipid A, Hep-Kdo2-Lipid A or HLA). LPS plays a key role in Gram-negative bacterial sepsis as a stimulator of the human immune response and has been used as an adjuvant in vaccines. As such, ongoing efforts towards inhibition of LPS biosynthetic enzymes to aid development of novel antimicrobial therapeutics has driven significant effort towards the characterization of these enzymes. Three heptosyltransferases are involved in the inner-core biosynthesis, with E. coli HepII being the last to be quantitatively characterized in vivo, as described herein. HepII shares modest sequence similarity with heptosyltransferase I (HepI) while maintaining a high degree of structural homology. Here we report the first kinetic and biophysical characterization of HepII and demonstrate the properties of HepII that are shared by HepI to include sugar donor promiscuity, and sugar acceptor induced secondary structural changes which results in significant thermal stabilization. HepII also has an increased catalytic efficiency and a significantly tighter binding affinity for both of its substrates, with an insensitivity to the number of acyl chains on the sugar acceptor. Additionally, a structural model of the HepII ternary complex, refined by molecular dynamics simulations, was developed to probe potentially important substrate-protein contacts and revealed the potential of Tryptophan (Trp) residues responsible for reporting on ligand binding. As was previously described for HepI, Tryptophan fluorescence in HepII allowed observation of substrate induced changes in Trp fluorescence intensity which enabled determination of substrate dissociation constants. Combined, these efforts meaningfully enhance our understanding of the Heptosyltransferase family of enzymes and will aid in future efforts to design novel, potent and specific inhibitors for this family of enzymes.
Psychiatric symptoms influence the performance on the Screener Intelligence and Learning Disabilities in general mental health care in The Netherlands
Authors: Nieuwenhuis Jeanet , Noorthoorn Eric , Lepping Peter , Mulder Niels , Nijman Henk 
Published: June 2022

Purpose
A recently published study showed a 41% prevalence of mild intellectual disability (MID) and borderline intellectual functioning (BIF) in a large sample of Dutch psychiatric patients. This study aims to examine if the outcomes of the Screener for Intelligence and Learning Disabilities (SCIL) were affected by the severity of psychiatric symptoms during admission.

Design/methodology/approach
The authors administered the SCIL and the Kennedy Axis V (domain psychological impairment) at two moments when patients were sufficiently stabilised and just before discharge.

Findings
A total of 86% of the respondents had the same outcome regardless of the time of administration. The Kennedy score correlated modestly with changes in the SCIL scores, suggesting that the severity of psychiatric symptoms just modestly affected the performance.

Practical implications
Recognising MID/BIF in mental health care is essential but challenging for clinicians. The authors concluded that screening with the SCIL allows clinicians to identify patients with MID/BIF at an early stage of their admission, which helps to individualise treatment and reduce the risk of aggression, coercive measures and prolonged admissions. However, the authors prefer to assess all patients on cognitive impairment as early as possible after referral at a more stable moment in time.

Originality/value
To the best of the authors’ knowledge, there is no research concerning screening instruments on MID/BIF used at admission wards in Mental Health Care.
Importance of first-line employees in lean implementation in SMEs: a systematic literature review
Authors: Knapić Viktorija , Rusjan Borut , Božič Katerina 
Published: June 2022

Purpose
Existing research evidence shows a fragmented understanding of the roles of first-line employees (FLEs) as essential factors for successful lean implementation in small- and medium-sized enterprises (SMEs), provoking recent calls for additional research on the identification of enablers and barriers for lean acceptance among workers. Therefore, this paper aims to identify related enablers and barriers to lean implementation among FLEs and determine future research avenues for improving the understanding of lean methodology implementation in SMEs.

Design/methodology/approach
Relying on a systematic literature review methodology, the authors aimed to synthesize and evaluate available peer-reviewed papers on the role of FLEs in lean implementation in SMEs. General descriptive and thematic analysis comprehensively depicted the selected research topic and identified the main themes within collected papers and potential future research questions.

Findings
The authors identified four main themes related to FLEs’ role in lean implementation: cultural change factors, employee characteristics, management involvement and lean job design. Within each theme, the authors present a comprehensive overview of FLE-related factors and associated enablers and barriers that should be considered for a successful lean implementation in SMEs.

Practical implications
The research outcomes are important to practicing managers in SMEs, helping them facilitate lean acceptance and enhance the likelihood of successful lean implementation.

Originality/value
The insights from this study present building blocks in developing a lean implementation model for SMEs that considers the FLEs’ role more comprehensively.
The importance of adopting an intersectionality approach to refugee status determination procedures: lessons from Greece, Israel and Uganda
Authors: Sarkin Jeremy Julian , Morais Tatiana 
Published: June 2022

PurposeThis paper argues that intersectionality ought to be a vital tool to identify and recognise those who are refugees. It provides a useful way to distinguish refugees from migrants as well as making it possible to screen for asylum seekers who are at greater risk of experiencing specific vulnerable situations, such as sexual and gender-based violence. This study therefore argues that intersectionality is useful for risk assessment processes as well as for triggering special protection mechanisms.Design/methodology/approachThis research article draws from a cross-cultural empirical study conducted in Greece, Uganda, and Israel on problems asylum seekers and refugees face in host countries.FindingsIt is argued that while it is important to identify and screen for asylum seekers who have survived or are at greater risk of experiencing sexual and gender-based violence to provide special protection, it may lead to what has been called a “categorical fetishism”, in this case, applied to vulnerability. Such stigmatising and disempowering perceptions of refugees and their experiences may lead to the view that there are “good” refugees and asylum seekers who are worthy of protection, as opposed to “others”.Originality/valueThis original empirical article provides a new way of examining issues of refugee status determination to ensure fairer ways of doing so.
Supervisor bottom line mentality, self-regulation impairment and unethical pro-organizational behavior: investigating the moderating effect of perceived employability
Authors: Kamran Komal , Farasat Mobina , Azam Akbar , Atif Mian Muhammad 
Published: June 2022

Purpose
Unethical pro-organizational behavior (UPB) is one of the major reasons behind high-profile financial frauds in the recent past. This study aims to explore how an exclusive focus on financial outcomes, i.e. supervisor bottom-line mentality (BLM) leads to UPB among employees and highlights the critical role of self-regulation impairment and perceived employability in the process. Drawing on self-regulation theory, this study examines how BLM and perceived employability interactively impact self-regulatory strength, which ultimately influences UPB.

Design/methodology/approach
The theoretical model is tested through a time-lagged field study of 171 employees and hypothesis testing in SPSS PROCESS Macros.

Findings
Results suggest that self-regulation impairment mediates a positive relationship between supervisor BLM and employee UPB and perceived employability moderates this indirect association between BLM and UPB, wherein the indirect positive relationship is stronger when perceived employability is low (than high).

Originality/value
This study contributes to the BLM and UPB literature by identifying the critical role of perceived employability and suggesting that UPB is an impulsive action rather than an intentional move.
Memetic algorithm for unrelated parallel machine scheduling problem with grey processing times
Authors: Arık Oğuzhan Ahmet 
Published: June 2022

Purpose
This paper aims to provide a promising memetic algorithm (MA) for an unrelated parallel machine scheduling problem with grey processing times by using a simple dispatching rule in the local search phase of the proposed MA.

Design/methodology/approach
This paper proposes a MA for an unrelated parallel machine scheduling problem where the objective is to minimize the sum of weighted completion times of jobs with uncertain processing times. In the optimal schedule of the problem’s single machine version with deterministic processing time, the machine has a sequence where jobs are ordered in their increasing order of weighted processing times. The author adapts this property to some of their local search mechanisms that are required to assure the local optimality of the solution generated by the proposed MA. To show the efficiency of the proposed algorithm, this study uses other local search methods in the MA within this experiment. The uncertainty of processing times is expressed with grey numbers.

Findings
Experimental study shows that the MA with the swap-based local search and the weighted shortest processing time (WSPT) dispatching rule outperforms other MA alternatives with swap-based and insertion-based local searches without that dispatching rule.

Originality/value
A promising and effective MA with the WSPT dispatching rule is designed and applied to unrelated parallel machine scheduling problems where the objective is to minimize the sum of the weighted completion times of jobs with grey processing time.
Bolt stripping failure and ductility of end plate beam-column connections at ambient and elevated temperatures
Authors: Shaheen Mohamed A. , Cunningham Lee S. , Foster Andrew S.J. 
Published: June 2022

PurposeThe effect of bolt stripping failure on the ductility of steel end plate beam-column connections has received relatively little investigation to date. The objective with the present work is to establish a validated numerical model of end plate connections at elevated temperatures, which predicts the mechanical behaviour and failure modes observed in the experimental tests including the bolt stripping failure. Furthermore, the validated FE model was used to investigate the effect of stripping failure on both the rotational and load-bearing capacity of end plate connection.Design/methodology/approachThe analysis was conducted on a validated numerical model of end plate connections at elevated temperatures, which predicts the mechanical behaviour and failure modes observed in the experimental tests including the bolt stripping failure. The material was modelled considering ductile damage initiation and evolution featured in ABAQUS/Standard.FindingsThis study demonstrates that thick end plates can prevent stripping failure which significantly improves the rotational capacity of the connection. This failure mode can develop readily with thin end plates; however the effect is often unrealistically mitigated through idealised experimental tests. The rotational capacity of a connection can be 5.0 times higher if stripping failure is avoided, particularly at elevated temperatures. Eurocode 3 part 1.8 does not consider the possibility of stripping failure when discussing the requirements for plastic analysis. It is concluded in the present study that by allowing for the possibility of bolt stripping, the mode of failure can often shift from end plate failure to bolt stripping, this in turn significantly reduces the connection rotational capacity.Originality/valueThe effect of bolt stripping failure on the ductility of steel end plate beam-column connections has received relatively little investigation to date.