bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perceived Stress in First-Year Medical Students and its Effect on Gut Microbiota
Authors: Rusling Matthew Revere , Johnson Joseph , Shoskes Aaron , Jie Chunfa , Yuan Li-Lian 
Published: November 2019

AbstractMedical students are constantly under stress caused by strenuous medical programs, which may exert persistent physical and psychological effects on their well-being. Using medical students as a model population, this work explores the gut microbiome as a potential contributing mechanism for why individuals exposed to similar stimuli react variably. We evaluated the relationship of gut microbiome composition of first year medical students and stress resilience over a period of 4 months. Our objective was to identify gut microbiome characteristics of individuals that showed long-term stress resilience. Students were voluntarily recruited and screened for lifestyle and environmental factors at 3 timepoints during the first semester. Fecal samples were also collected at each timepoint. In order to identify candidates with stress resilience, their perceived stress and depression levels were normalized and summed to produce a psychologic index score. The most notable finding is a correlation between psychologic resiliency of Bacteriodete:Firmicute abundance as well as a relationship between durable resiliency and microbiome stability. Phylogenetic assembly of participants by microbiome relatedness found that 100% of subjects who were resilient to stress across all timepoints (n=8) were phylogenetically clustered in adjacent positions, showing a high degree of temporal stability. Of participants who were not durably resilient to stress, only 62% of participants (n=8) showed microbiomes that were phylogenetically related across the same 4 month period. We identified 2,102 Operational Taxonomic Units (OTUs) which were unique to the durable resilience group and 94 OTUs which were unique to the susceptible group. Of the 4,794 observed OTUs, 6.1% (n=294) were significantly different between groups. These findings support that the gut microbiome may play an important role in stress resilience at a time scale of 4 months. A better understanding of the role of the gut microbiome in stress resilience may shed light on potential treatment to reduce stress/anxiety in general, as well as to promote wellbeing of our future health care providers and physicians.
Sex chromosome pairing mediated by euchromatic homology inDrosophilamale meiosis
Authors: Hylton Christopher A. , Hansen Katie , Bourgeois Andrew , Tomkiel John E. 
Published: November 2019

ABSTRACTTo maintain proper ploidy, haploid sex cells must undergo two subsequent meiotic divisions. During meiosis I, homologs pair and remain conjoined until segregation at anaphase.Drosophila melanogasterspermatocytes are unique in that the canonical events of meiosis I including synaptonemal complex (SC) formation, double-strand DNA breaks, and chiasmata are absent. Sex chromosomes pair at intergenic spacer sequences within the heterochromatic rDNA while euchromatin is required to pair and segregate autosomal homologies, suggesting that pairing may be limited to specific sequences. However, previous work generated from genetic segregation assays or observations of late prophase I/prometaphase I chromosome associations fail to differentiate pairing from conjunction. Here, we separately examined the capability of X euchromatin to pair and conjoin using an rDNA-deficient X and a series ofDp(1;Y)chromosomes. Genetic assays showed that duplicated X euchromatin can substitute for endogenous rDNA pairing sites. Segregation was not proportional to homology length, and pairing could be mapped to nonoverlapping sequences within a singleDp(1;Y). Using fluorescentin situhybridization (FISH) to early prophase I spermatocytes, we showed that pairing occurred with high fidelity at all homologies tested. Pairing was unaffected by the presence of X rDNA, nor could it be explained by rDNA magnification. By comparing genetic and cytological data, we determined that centromere proximal pairings were best at segregation. Segregation was dependent on the conjunction protein Stromalin in Meiosis while the autosomal-specific Teflon was dispensable. Overall, our results suggest that pairing may occur at all homologies, but there may be sequence or positional requirements for conjunction.ARTICLE SUMMARYDrosophilamales have evolved a unique system of chromosome segregation in meiosis that lacks recombination. Chromosomes pair at selected sequences suggesting that early steps of meiosis may also differ in this organism. Using Y chromosomes carrying portions of X material, we show that pairing between sex chromosomes can be mediated by sequences other than the previously identified rDNA pairing sites. We propose that pairing may simply be homology-based and may not differ from canonical meiosis observed in females. The main difference in males may be that conjunctive mechanisms that join homologs in the absence of crossovers.
Central norepinephrine transmission is required for stress-induced repetitive behavior in two rodent models of obsessive-compulsive disorder
Authors: Lustberg Daniel , Iannitelli Alexa , Tillage Rachel P. , Pruitt Molly , Cameron Liles L. , Weinshenker David 
Published: November 2019

AbstractRationaleObsessive-compulsive disorder (OCD) is characterized by repetitive behaviors exacerbated by stress. Many OCD patients do not respond to available pharmacotherapies, but neurosurgical ablation of the anterior cingulate cortex (ACC) can provide symptomatic relief. Although the ACC receives noradrenergic innervation and expresses adrenergic receptors (ARs), the involvement of norepinephrine (NE) in OCD has not been investigated.ObjectiveTo determine the effects of genetic or pharmacological disruption of NE neurotransmission on marble burying (MB) and nestlet shredding (NS) in two animal models of OCD.MethodsWe assessed NE-deficient (Dbh -/-) mice and NE-competent (Dbh +/-) controls in MB and NS tasks. We also measured the effects of anti-adrenergic drugs on NS and MB in control mice and the effects of pharmacological restoration of central NE in Dbh -/- mice. Finally, we compared c-fos induction in the locus coeruleus (LC) and ACC of Dbh -/- and control mice following both tasks.ResultsDbh -/- mice virtually lacked MB and NS behaviors seen in control mice but did not differ in the elevated zero maze (EZM) model of general anxiety-like behavior. Pharmacological restoration of central NE synthesis in Dbh -/- mice completely rescued NS behavior, while NS and MB were suppressed in control mice by anti-adrenergic drugs. Expression of c-fos in the ACC was attenuated in Dbh -/- mice after MB and NS.ConclusionThese findings support a role for NE transmission to the ACC in the expression of stress-induced compulsive behaviors and suggest further evaluation of anti-adrenergic drugs for OCD is warranted.
Escort-like somatic cells mediate early mouse fetal ovarian development but surface-derived Lgr5+ cells support primordial follicles
Authors: Niu Wanbao , Spradling Allan C. 
Published: November 2019

AbstractOvarian murine somatic cells are essential to form first wave medullar follicles and second wave primordial follicles. Using single cell RNA sequencing we characterized the transcriptomes of both somatic and germline ovarian cells during fetal and early neonatal development. Wnt4-expressing somatic cells we term “escort-like cells (ELCs)” interact with incoming germ cells and early developing cysts of both sexes. In the medullar region, ELCs differentiate into the granulosa cells of fast-growing first wave follicles. In contrast, after E12.5, Lgr5+ pre-granulosa cells ingress from the ovarian surface epithelium and replace cortical escort-like cells. These surface-derived cells become the main population of granulosa cells supporting primordial follicles, and differ in transcription from ELC derivatives. Reflecting their different cellular origins, ablation of Lgr5+ cells at E16.5 using Lgr5-DTR-EGFP eliminates second wave follicles, but first wave follicles continue to develop normally and support fertility. Our findings provide striking evidence that somatic cell behavior supporting germline cyst development in mice and Drosophila has been evolutionarily conserved.
Implementation of Bayesian Multiple Comparison Correction in the Second-Level Analysis of fMRI Data: With Pilot Analyses of Simulation and Real fMRI Datasets Based on Voxelwise Inference
Authors: Han Hyemin 
Published: November 2019

AbstractWe developed and tested Bayesian multiple comparison correction method for Bayesian voxelwise second-level fMRI analysis with R. The performance of the developed method was tested with simulation and real image datasets. First, we compared false alarm and hit rates, which were used as proxies for selectivity and sensitivity, respectively, between Bayesian and classical inference were conducted. For the comparison, we created simulated images, added noise to the created images, and analyzed the noise-added images while applying Bayesian and classical multiple comparison correction methods. Second, we analyzed five real image datasets to examine how our Bayesian method worked in realistic settings. When the performance assessment was conducted, Bayesian correction method demonstrated good sensitivity (hit rate ≥ 75%) and acceptable selectivity (false alarm rate < 10%) when N ≤ 8. Furthermore, Bayesian correction method showed better sensitivity compared with classical correction method while maintaining the aforementioned acceptable selectivity.
Differential Effects of “Resurrecting” Csp Pseudoproteases duringClostridioides difficileSpore Germination
Authors: Lauren Donnelly M. , Forster Emily R. , Rohlfing Amy E. , Shen Aimee 
Published: November 2019

AbstractClostridioides difficileis a spore-forming bacterial pathogen that is the leading cause of hospital-acquired gastroenteritis.C. difficileinfections begin when its spore form germinates in the vertebrate gut upon sensing bile acids. These germinants induce a proteolytic signaling cascade controlled by three members of the subtilisin-like serine protease family, CspA, CspB, and CspC. Notably, even though CspC and CspA are both pseudoproteases, they are nevertheless required to sense germinants and activate the protease, CspB. Thus, CspC and CspA are part of a growing list of pseudoenzymes that play important roles in regulating cellular processes. However, despite their importance, the structural properties of pseudoenzymes that allow them to function as regulators remain poorly understood. Our recently determined crystal structure of CspC revealed that its degenerate site residues align closely with the catalytic triad of CspB, so in this study we tested whether the ancestral protease activity of the CspC and CspA pseudoproteases could be “resurrected.” Restoring the catalytic triad to these pseudoproteases failed to resurrect their protease activity, although the mutations differentially affected the stability and function of these pseudoproteases. Degenerate site mutations destabilized CspC and impaired spore germination without impacting CspA stability or function. Thus, our results surprisingly reveal that the presence of a catalytic triad does not necessarily predict protease activity. Since close homologs ofC. difficileCspA occasionally carry an intact catalytic triad, our results imply that bioinformatics predictions of enzyme activity may overlook pseudoenzymes in some cases.
GFP fusion protein with embedded foreign peptide
Authors: Glukhova K.A. , Klyashtorny V.G. , Melnik B.S. 
Published: November 2019

AbstractFrom the point of view structural biology and protein engineering the green fluorescent protein (GFP) is an exceptionally attracting object. The tertiary structure of GFP is quite unique: it reminds a “cylinder” or a “barrel” consisting of beta-layers that contains an alpha-helix inside. The “barrel” is a special container for an alpha-helix serving to protect the latter from the influence of the surroundings. Therefore a reasonable question arises whether the “barrel” can function as a container for preservation and isolation of other peptides. The alpha-helix itself contains hydrophilic amino acids, whereas inside the barrel there are many molecules of bound water. We supposed that the central alpha-helix of green fluorescent protein could be substituted for foreign peptide. In this study we checked the possibility for creation of such a system on base of GFP, where the toxic peptide is isolated from the environment inside the protein. The modification of green fluorescent protein was carried out. An antimicrobial peptide was inserted into the central alpha-helix. The results of our experiments show that such a chimeric protein is compact, soluble and non-toxic for the producing cell culture, but its structure is destabilized. The obtained data show that the idea of use of green fluorescent proteins as a «container» for storing foreign peptides could be realized.
dP75 safeguards oogenesis by preventing H3K9me2 spreading
Authors: Dou Kun , Liu Yanchao , Zhang Yingpei , Wang Chenhui , Huang Ying , Zhang ZZ Zhao 
Published: November 2019

ABSTRACTServing as a host factor for HIV integration, LEDGF/p75 has been under extensive study as a potential target for therapy. However, as a highly conserved protein, its physiological function remains to be thoroughly elucidated. Here we characterize the molecular function of dP75, theDrosophilahomolog of p75, during oogenesis. dP75 binds to transcriptionally active chromatin with its PWWP domain. The C-terminus IBD domain-containing region of dP75 physically interacts with the histone kinase Jil-1 and stabilizes itin vivo. Together with Jil-1, dP75 prevents the spreading of the heterochromatin mark–H3K9me2–onto genes required for oogenesis and piRNA production. Without dP75, ectopically silencing of these genes disrupts oogenesis, activates transposons, and causes animal sterility. We propose that dP75, the homolog of an HIV host factor inDrosophila, partners with Jil-1 to ensure gene expression during oogenesis by preventing ectopic heterochromatin spreading.
Contentious politics and democratization in Hong Kong
Authors: Ortmann Stephan 
Published: November 2019

PurposeThe purpose of this paper is to explain why many activists in Hong Kong have shifted from demanding democracy to independence while, at least for a short time, there have been more aggressive tactics which culminated in the Fishball Revolution of 2016.Design/methodology/approachBased on event analysis, participant observation in recent protests, as well as interviews with participants and non-participants in various pro-democracy protests, this paper traces the changes of the democracy movement from 1997 until 2018.FindingsThe paper demonstrates that the inability of the democracy movement to make progress has contributed to a change in the goals and tactics of some pro-democracy activists. The goals have shifted from moderate democratic reforms to much more revolutionary demands including calls for full autonomy or independence while the approach has shifted from an institutionalized approach toward more aggressive tactics such as illegal forms of resistance. During the Lunar New Year in 2016, the growing frustrations over perceived threats to the local culture have, for the first time since the handover, even led to the use of violence.Originality/valueThis paper views contentious politics in Hong Kong through McAdam’s distinction of reform-oriented and revolutionary goals as well as institutionalized and non-institutionalized tactics. This provides a new perspective for explaining the rise of localism and Hong Kong nationalism.
Expectations do not always hurt! Tying organizational career expectations to employment mode
Authors: Ahmad Bilal , Bilal Ahmad Raza , Hai Mahnoor 
Published: November 2019

PurposeThe past decade has witnessed a surge in research focused on universal career development needs. In contrast, the purpose of this paper is to offer a contingency perspective based on self-efficacy theory by examining the relationship between the employees’ perceived mode of employment and expectations of career development opportunities attached to the employer. The authors hypothesized that perceived mode of employment determines employees’ expectations about receiving career development opportunities offered by the employer.Design/methodology/approachResponses from 203 banking employees were obtained through a structured questionnaire. Perceived employment mode was identified through Ward’s method of cluster analysis. The proposed hypothesis was tested by using one-way analysis of variance.FindingsEmployees across all modes of employment (knowledge-based, job-based, contract-based and alliance-based) were found to be similar with respect to their need for career development programs. However, employees positioned in knowledge-based and alliance-based modes were also interested in career appraisal and career training.Originality/valueThe study contributes to the existing body of knowledge on career management by imparting preliminary insights into the way employees’ expectations of organizational career management opportunities vary according to their perceived mode of employment based on self-efficacy theory.
Substitute or complementary
Authors: Chen Bo , Saghaian Sayed , Tyler Mark 
Published: November 2019

PurposeThe purpose of this paper is to examine the relationship between US farmers’ adoption of organic farming and direct marketing, both of which are increasingly important practices in the US agricultural and food sector. In addition, the effects of the two practices on farm income are evaluated.Design/methodology/approachThe research uses the Agricultural and Resource Management Survey from the US Department of Agriculture. Farmers’ adoption of the two practices is modeled with a simultaneous linear probability model, which accounts for the possible linkage between the adoption of the two practices in farmers’ decision-making process. Farm income is modeled with a linear regression model, accounting for the possible endogeneity of the adoption of the two practices.FindingsThe main finding is that farmers’ adoption of organic farming decreases their probability of adopting direct marketing, whereas the reverse effect is insignificant. In addition, organic farming helps to improve gross farm income, whereas the effect of direct marketing is insignificant.Practical implicationsThese results facilitate better coordination among numerous government programs aimed at promoting organic farming or direct marketing in the US.Originality/valueThis paper extends previous literature by specifically accounting for the possible linkage between farmers’ adoption of organic farming and direct marketing, and demonstrates that farmers do not make the decision to adopt one particular practice in isolation.
Understanding the antecedents of car sharing usage: an empirical study in Italy
Authors: Guglielmetti Mugion Roberta , Toni Martina , Di Pietro Laura , Pasca Maria Giovina , Renzi Maria F. 
Published: November 2019

PurposeSustainable mobility and collaborative consumption are debated issues in the literature. In this field, car sharing (CS) represents a growing tendency that attracts interest by academicians for its potential positive impact on sustainability. This study aims to understand the main drivers of CS usage, unveiling the role of service quality and the possible inhibitors.Design/methodology/approachBased on theoretical assumptions in the literature, the authors developed a theoretical framework that aims at understanding the main antecedents of CS usage. An empirical investigation involving the city of Rome (Italy) was performed. The study presents a qualitative and quantitative survey, while the proposed theoretical model has been tested through structural equation modelling statistical techniques.FindingsThe findings show that usefulness positively affects the intention to use CS services. Moreover, the green attitude and expected service quality indirectly influence the intention to use CS services impacting perceived usefulness. The results show that the expected service quality has a strong influence on usefulness, whereas green attitude has a weaker influence on usefulness. The intention to use CS services is directly influenced by the usefulness and inhibitors that affect it negatively.Originality/valueThe originality of this paper lies in the fact that this study discloses the main antecedents of the intention to use CS services, emphasizing the role of service quality. This study provides fruitful insights to policy and decision-makers to understand how to improve the CS usage in the urban transport system of the city of Rome. It suggests developing a higher level of service quality in the vehicles, suitable technological applications and effective communication as well as on overcoming its main inhibitors.
An investigation into the relationship between materialism and green purchase behavior in Vietnam and Taiwan
Authors: Thi Tuyet Mai Nguyen 
Published: November 2019

Purpose
The purpose of this paper is to investigate the impact of materialistic values on purchase intention (PI) toward green products among consumers in Vietnam and Taiwan, two Asian countries with different levels of economic development.

Design/methodology/approach
This research employs the extended theory of planned behavior (TPB) with an integration of materialism. To serve the purpose of this study, two consumer surveys were conducted in Hanoi (Vietnam) and Taipei (Taiwan). The structural equation modeling was employed to test the proposed model and hypotheses.

Findings
This study examined the impact of some antecedents of green PI among consumers in Vietnam and Taiwan, focusing on the indirect impact of materialistic values (through attitude). All five hypotheses received support from the Vietnam data, confirming the significant impacts of materialistic values (i.e. success and happiness) on attitude, and all three antecedents from the TPB model (i.e. attitude, subjective norms and perceived behavioral control) as positive predictors of green PI. For the Taiwan data, the findings were similar to those from the Vietnam data, except insignificant impact of success value on attitude toward buying green products.

Originality/value
This research is expected to contribute to the extant literature by enriching the knowledge of the interesting and important relationship between materialistic values and green purchase behavior among consumers in two Asian markets where, to the author’s best understanding, only modest research effort has been given to explore this topic.
Evolution and decline of MNCs from a leadership-quality perspective- MNCs from the Brazilian market
Authors: Jneid Cherine 
Published: November 2019

PurposeThe purpose of this paper is to provide guidelines to IHRM by providing a set of personal and psychological competencies that are relevant to the development of global mindsets in global leaders.Design/methodology/approachThe authors adopted the qualitative research approach by conducting interviews with 22 top managers and organizing focus groups to 102 expatriated Brazilian global leaders.FindingsThe findings suggest that the language proficiency, the complexity of the global role and the positive psychological traits are highly relevant when developing global mindsets.Originality/valueThe researcher argues that the IHRM must review its practices regarding the management of international assignments which efficiency is overrated by top managers.