bluuebunny/crossref_metadata_2025_split huggingface dataset:
CRISPR-Cas guided mutagenesis of chromosome and virulence plasmid inShigella flexneriby cytosine base editing
Authors: Sharma Atin , Aden Ruqiya Omer , Puhar Andrea , Cisneros David A. 
Published: March 2022

AbstractShigellais a Gram-negative bacterium that invades the human gut epithelium. The resulting infection, shigellosis, is the deadliest bacterial diarrheal disease. Much of the information about the genes dictating the pathophysiology ofShigella, both on the chromosome and the virulence plasmid, was obtained by classical reverse genetics. However, technical limitations of the prevalent mutagenesis techniques restrict the generation of mutants in a single reaction to a small number, preventing large scale targeted mutagenesis ofShigellaand the subsequent assessment of phenotype. We adopted a CRISPR-Cas dependent approach, where a nickase Cas9 and cytidine deaminase fusion is guided by sgRNA to introduce targeted C→T transitions, resulting in internal STOP codons and premature termination of translation. In proof-of-principle experiments using anmCherryfluorescent reporter, we were able to generate loss-of-function mutants in bothE. coliandShigellawith up to 100% efficacy. Using a modified fluctuation assay, we determined that under optimized conditions, the frequency of untargeted mutations introduced by the Cas9-deaminase fusion is in the same range as spontaneous mutations, making our method a safe choice for bacterial mutagenesis. Further, we programmed the method to mutate well-characterized chromosomal and plasmid-borneShigellagenes and found the mutant phenotype to be similar to that of the reported gene deletion mutants, with no apparent polar effects at the phenotype level. This method can be used in a 96-well plate format to increase the throughput and generate an array of targeted loss-of-function mutants in a few days.ImportanceLoss-of-function mutagenesis is critical in understanding the physiological role of genes. Therefore, high-throughput techniques to generate such mutants are important for facilitating the assessment of gene function at a pace that matches system biology approaches. However, to our knowledge, no such method was available for generating an array of single gene mutants in an important enteropathogen -Shigella. This pathogen causes high morbidity and mortality in children and antibiotic resistant strains are quickly emerging. Therefore, determination of the function of unknownShigellagenes is of utmost importance to develop effective strategies to control infections. Our present work will bridge this gap by providing a rapid method for generating loss-of-function mutants. The highly effective and specific method has the potential to be programmed to generated multiple mutants in a single, massively parallel, reaction. By the virtue of plasmid compatibility, this method can be extended to other members of Enterobacteriaceae.
Adolescent parvalbumin expression in the left orbitofrontal cortex shapes sociability in female mice
Authors: Jeon Yi-Seon , Jeong Daun , Kweon Hanseul , Kim Jae-Hyun , Kim Choong Yeon , Oh Youngbin , Lee Young-Ho , Kim Chan Hyuk , Kim Sang-Gyu , Jeong Jae-Woong , Kim Eunjoon , Lee Seung-Hee 
Published: March 2022

AbstractThe adolescent social experience is essential for the maturation of the prefrontal cortex in mammalian species. However, it still needs to be determined which cortical circuits mature with such experience and how it shapes adult social behaviors in a sex-specific manner. Here, we examined social approaching behaviors in male and female mice after post-weaning social isolation (PWSI), which deprives social experience during adolescence. We found that the PWSI, particularly isolation during late adolescence, caused an abnormal increase in social approaches (hypersociability) only in female mice. We further found that the PWSI female mice showed reduced parvalbumin (PV) expression in the left orbitofrontal cortex (OFCL). When we measured neural activity in the female OFCL, a substantial number of neurons showed higher activity when mice sniffed other mice (social sniffing) than when they sniffed an object (object sniffing). Interestingly, the PWSI significantly reduced both the number of activated neurons and the activity level during social sniffing in female mice. Similarly, the CRISPR/Cas9-mediated knock-down of PV in the OFCLduring late adolescence enhanced sociability and reduced the social sniffing-induced activity in adult female mice via decreased excitability of PV+neurons and reduced synaptic inhibition in the OFCL. Moreover, optogenetic activation of excitatory neurons or optogenetic inhibition of PV+neurons in the OFCLenhanced sociability in female mice. Our data demonstrate that the adolescent social experience is critical for the maturation of PV+inhibitory circuits in the OFCL; this maturation shapes female social behavior via enhancing social representation in the OFCL.Significance StatementAdolescent social isolation often changes adult social behaviors in mammals. Yet, we do not fully understand the sex-specific effects of social isolation and the brain areas and circuits that mediate such changes. Here, we found that adolescent social isolation causes three abnormal phenotypes in female but not male mice: hypersociability, decreased PV+neurons in the OFCL, and decreased socially evoked activity in the OFCL. Moreover, PV deletion in the OFCLin vivocaused the same phenotypes in female mice by increasing excitation compared with inhibition within the OFCL. Our data suggest that adolescent social experience is required for PV maturation in the OFCL, which is critical for evoking OFCLactivity that shapes social behaviors in female mice.
Loss of the adhesion protein Kindlin-1 stimulates tumor clearance via modulation of Tregs
Authors: Webb Emily R , Dodd Georgia , Bullock Esme , Muir Morwenna , Frame Margaret C , Serrels Alan , Brunton Valerie G 
Published: March 2022

AbstractThe adhesion protein Kindlin-1 is over-expressed in breast cancer where it has been shown to be associated with metastasis-free survival, however, the mechanisms involved are poorly understood. Here, we report that Kindlin-1 promotes anti-tumor immune evasion in a mouse model of breast cancer. Deletion of Kindlin-1 in Met-1 mammary tumor cells leads to tumor regression following injection into immunocompetent hosts. This was associated with a reduction in tumor infiltrating Tregs and impairment of their immune-suppressive activities in Kindlin-1 depleted tumors. Similar changes in T cell populations were seen following depletion of Kindlin-1 in the polyomavirus middle T antigen (PyV MT)-driven mouse model of mammary tumorigenesis. Analysis of cytokines secreted from the Met-1 cells identified a significant increase in IL-6 secretion when Kindlin-1 was depleted. Conditioned media from Kindlin-1 depleted cells lead to a decrease in the ability of Tregs to suppress the proliferation of CD8+ T cells, which was dependent on IL-6 and depletion of CD25+ Tregs resulted in a reduction of Met-1 tumor growth in mice. Overall, these data identify a novel function for Kindlin-1 in the regulation of anti-tumor immunity through cytokine regulation of Treg number and function.
Confinement of unliganded EGFR by tetraspanin nanodomains gates EGFR ligand binding and signaling
Authors: Sugiyama Michael G. , Brown Aidan I. , Vega-Lugo Jesus , Scott Andrew M. , Jaqaman Khuloud , Fairn Gregory D. , Antonescu Costin N. 
Published: March 2022

AbstractThe epidermal growth factor receptor (EGFR) is a central regulator of cell physiology. EGFR is activated by ligand binding, triggering receptor dimerization, activation of kinase activity, and intracellular signaling. EGFR is transiently confined within various plasma membrane nanodomains, yet how this may contribute to regulation of EGFR ligand binding is poorly understood. To resolve how EGFR nanoscale compartmentalization gates ligand binding, we developed single-particle tracking methods to track the mobility of ligand-bound and total EGFR, in combination with modeling of EGFR ligand binding. In comparison to unliganded EGFR, ligand-bound EGFR was more confined and distinctly regulated by clathrin and tetraspanin nanodomains. Ligand binding to unliganded EGFR occurred preferentially in tetraspanin nanodomains, and disruption of tetraspanin nanodomains impaired EGFR ligand binding and altered the conformation of the receptor’s ectodomain. We thus reveal a novel mechanism by which EGFR confinement within tetraspanin nanodomains regulates receptor signaling at the level of ligand binding.
Theoretical Quantification of the Polyvalent Binding of Nanoparticles Coated with Peptide-MHC to TCR-Nanoclusters
Authors: Pineros-Rodriguez Manuela , Richez Louis , Khadra Anmar 
Published: March 2022

AbstractNanoparticles (NPs) coated with pMHCs can reprogram a specific type of CD4+ T cells into diseasesuppressing T regulatory type 1 cells by binding to their TCRs expressed as TCR-nanoclusters (TCRnc). NP size and number of pMHCs coated on them (called valence) can be adjusted to increase their efficacy. Here we explore how this polyvalent interaction is manifested and examine if it can facilitate T cell activation. This is done by developing a multiscale biophysical model that takes into account the complexity of this interaction. Using the model, we quantify pMHC insertion probabilities, dwell time of NP binding, TCRnc carrying capacity, the distribution of covered and bound TCRs by NPs, and cooperativity in the binding of pMHCs within the contact area. Model fitting and parameter sweeping further reveal that moderate jumps between IFNγ dose-response curves at low valences can occur, suggesting that the geometry of NP binding can prime T cells for activation.
A method to estimate the effective point spread function of static single molecule localization microscopy images
Authors: Shaw Thomas R. , Fazekas Frank J. , Kim Sumin , Flanagan-Natoli Jennifer C. , Sumrall Emily R. , Veatch S. L. 
Published: March 2022

ABSTRACTSingle molecule localization microscopy (SMLM) permits the visualization of cellular structures an order of magnitude smaller than the diffraction limit of visible light, and an accurate, objective evaluation of the resolution of an SMLM dataset is an essential aspect of the image processing and analysis pipeline. Here we present a simple method that uses the pair autocorrelation function evaluated both in space and time to measure the time-interval dependent effective point spread function of SMLM images of static samples. Using this approach, we demonstrate that experimentally obtained images typically have effective point spread functions that are broader than expected from the localization precision alone, due to additional uncertainty arising from factors such as drift and drift correction algorithms. The method is demonstrated on simulated localizations, DNA origami rulers, and cellular structures labelled by dye-conjugated antibodies, DNA-PAINT, or fluorescent fusion proteins.STATEMENT OF SIGNIFICANCESingle molecule localization microscopy (SMLM) is a class of imaging methods that resolve fluorescently labeled structures beyond the optical resolution limit of visible light. SMLM detects stochastically blinking labels over time, and localizes each blink with precision of order 10 nm. The effective resolution depends on factors such as signal-to-noise ratio, localization algorithm, and several post-processing steps such as stage drift correction. We present a method to evaluate this effective resolution by taking advantage of temporal correlations of fluorophore blinking to separate the distribution of pairs of localizations from the same molecule from those from different molecules. The method is robust on useful timescales for a range of SMLM probes.
Predicting and promoting the consumption of plant-based meat
Authors: Carfora Valentina , Morandi Maria , Catellani Patrizia 
Published: March 2022

PurposeThe present research aimed to understand how to predict and promote plant-based meat (PBM) consumption.Design/methodology/approachIn Study 1 (N = 550), the authors investigated the psychosocial antecedents of the intentions to add PBM and to replace animal meat with PBM. In Study 2 (N = 390), the authors tested the effectiveness of different environmental messages promoting PBM consumption. The authors compared the effects of an addition message condition (i.e. a message promoting the addition of PBM to one's diet), a replacement message condition (i.e. a message promoting the replacement of animal meat with PBM) and a control condition (i.e. no message). In both studies, the authors considered the moderation of past PBM consumption (PMB eaters vs PBM noneaters).FindingsStudy 1 showed that a positive attitude towards eating PBM and a high awareness of the environmental consequences of meat production were key antecedents of participants' intention to eat PBM. The role of the other psychosocial antecedents varied according to past PBM consumption. Study 2 showed that both addition and replacement messages increased non-PBM eaters' positive attitude towards eating PBM and in turn willingness to pay for PBM. Instead, only replacement messages increased PBM eaters' willingness to pay for PBM.Originality/valueThe present research developed a model integrating the key psychosocial predictors of people's intentions to eat PBM. Furthermore, it is the first research that compared the persuasiveness of different environment messages to promote PBM consumption.
Confident or captured? Commercial producers in South Africa
Authors: Cloete Kandas , Mann Stefan , Delport Marion 
Published: March 2022

PurposeAmong the many things that land reform in South Africa suffers from is the lack of scientific attention paid to the willingness of commercial producers to exit or contract. This research aims to contribute to literature on this phenomenon.Design/methodology/approachThe interplay between the business confidence and the opportunity costs of a farming enterprise represented in a survey sample of 450 commercial farm owners is investigated, paying special attention to owners who want to, but cannot exit.FindingsThe regression analysis suggests that both forces have a strong influence on structural change, as they depict the rather complex interplay between the two main factors that may keep farms in business, one of which is a positive business climate and the other the capital invested. A subsequent cluster analysis indicates that there is a major cluster of producers who are pessimistic about the prospects of their farming business, but who are unable or unwilling to leave their farms.Research limitations/implicationsA limitation of our study is the fairly small sample size (91 exiters in the sample), so caution is advised in generalising the results. Another limitation is the overrepresentation of the Western Cape.Practical implicationsIt is likely that the productivity of South African agriculture could improve if some of these producers caught in the “system” could leave farming to create new opportunities for entrepreneurial entrants.Originality/valueThe importance of a captured state has been neglected both in theoretical frameworks and in practical concepts of commercial agriculture in South Africa.
In search of a fertile entrepreneurial landscape: how to keep it on the level
Authors: Claar Victor V. 
Published: March 2022

PurposeRecent analysis suggests entrepreneurship is in decline. If so, some argue that the appropriate policy response is to devote even further government intervention to nurture both fledgling ventures as well as entirely new undertakings, lamenting the fact that much current economic policy caters to already-successful firms – thereby creating a decision-making environment that stacks the deck against would-be entrepreneurs. While it is indeed true that entrepreneurial ventures lead to value creation over time, this paper argues that the answer to any slowdown in entrepreneurship is not to add even more policy Band-Aids to an already broken system of carve-outs, exemptions, subsidies and tax breaks. Instead the solution to bad policy is to unwind bad policy that favors Goliaths over Davids, thereby creating a level playing field for all. Any attempt to use government initiatives to spur entrepreneurship will, over the longer term, only serve to distort the economic outcomes society would have observed as the product of a system of rule-of-law, clearly defined and enforced property rights and freely functioning markets that permit entrepreneurs, investors, consumers and savers to make the most sensible choices available to them.Design/methodology/approachThis essay cites fundamental pieces of existing entrepreneurial research to make its argument.FindingsRather than adding even more policy initiatives to address any slowdown in entrepreneurship, policymakers should aspire to create the most fertile environment possible to foster entrepreneurial activity. Adding more policies on top of existing ones presumes to know which policies are better than others. Even when perceived as neutral, policy incentives cannot improve upon the outcomes of the unseen price system.Originality/valueThis paper reminds readers that entrepreneurship is vital to economic flourishing, while reminding readers that even policy actions presumed to be beneficial likely bear unintended consequences because they bring their own disruptions to the decision-making environment.
Frontline leadership for implementing clinical guidelines in Norwegian mental health services: a qualitative study
Authors: Nordin Håkan , Rørtveit Kristine , Mathisen Gro Ellen , Joa Inge , Johannessen Jan Olav , Ruud Torleif , Hartveit Miriam 
Published: March 2022

PurposeThe purpose of this study was to explore and interpret how frontline leaders define, experience and rationalise their approaches to the successful implementation of clinical guidelines in mental health care.Design/methodology/approachEmploying an interpretative phenomenological design, the authors conducted and analysed individual interviews of frontline leaders at 14 psychiatric clinics involved in a national study of implementing evidence-based clinical guidelines in mental health.FindingsThe authors found a broad spectrum of attitudes and attributes, as well as a wide repertoire of strategies for frontline implementation leadership. Three main approaches were revealed, comprising “Curious and welcoming”, “Integrity and setting standards” and “Caring and collegial”.Research limitations/implicationsThe study present what experienced frontline leaders emphasise to enable implementation of guidelines, not empirical pieces of evidences for what they in fact do or if these actions lead to implementation. The generalisability to other settings is unknown. Another sample profile, context or organisational level may have impacted the result. The concreteness of the frontline leaders’ considerations, approaches and actions gives important knowledge about frontline leaders leadership across traditional leadership theories.Originality/valueExisting leadership theories describe different leadership styles, while this study reveals the need for a wide range of approaches to balance the many needs and demands. The complexity of leadership approaches this study found is in line with implementation theories; thus, the present study incorporates implementation science into the leadership literature.
Can the components of green intellectual capital influence employee green behavior? An empirical analysis on Indian energy sector using the partial least squares method
Authors: Ghosh Arpita , Haque Shamima 
Published: March 2022

PurposeThe study aims to explore the relationship between the dimensions of green intellectual capital (GIC) and employee green behavior (EGB).Design/methodology/approachA survey has been conducted among a random representative population of employees working for the energy-sector organizations in India to collect data for this study. Exploratory factor analysis (EFA) for GIC supports the inclusion of the new dimension in its construct. Confirmatory factor analysis (CFA) validates the measurement model. Hypothesized relationships have been examined by applying structural equation modeling using partial least squares method.FindingsResults corroborate that all the four dimensions of GIC have varying degrees of significant positive impact on EGB. The study contributes to the existing literature by extending the understanding of the concept of GIC and its connection with EGB using natural-resource based theory and social cognitive theory (SCT).Originality/valueThe study has empirically examined the relationship between GIC and EGB in the context of a developing country like India. Moreover, unlike the existing literature that have classified GIC into green human capital (GHC), green structural capital (GSC) and green relational capital (GRC), the study identifies green spiritual capital (GSpC) as another important dimension of GIC which is an intangible asset and highly relevant in influencing altruistic activities like green behavior. The study presents significant implications for managers and policy-makers for ensuring EGB by investing in GIC resources.
The impact of supplier innovation on buyer innovation and the moderating effects of geographic distance, financial interdependence and technical similarity
Authors: Elking Isaac , Cantor David E. , Hofer Christian 
Published: March 2022

PurposeThis study aims to examine the extent to which a buying firm can leverage the firm's supplier's innovations to boost the firm's own innovation performance and key moderators to this relationship. Grounded in social embeddedness theory, the authors explore the role of dyadic embeddedness between a buyer and supplier as a facilitator of buyer innovation.Design/methodology/approachNegative binomial regression was used to empirically analyze a large sample of dyadic observations from the USA manufacturing industry. Measures were developed from data acquired from Compustat, LexisNexis and Bloomberg.FindingsThe findings indicate that supplier innovation has a positive impact on a buyer firm's innovation output, particularly when the firms are technically similar and when there is a higher degree of financial interdependence in the buyer–supplier dyad.Originality/valueThis study provides important insights into how supplier firms can facilitate buyer innovation as and how relational factors suggested by social embeddedness theory act to strengthen this effect. Through a theoretical-based empirical examination of supply chain dyads, the findings highlight the importance of financial interdependence and technical similarity when buyers seek to benefit from supplier innovation capabilities.