753 research outputs found
Location and group size influence decisions in simulated intergroup encounters in banded mongooses
In social species that cooperatively defend territories the decision to retreat or attack in contests between groups is likely to depend on ecological and social factors. Previous studies have emphasized the importance of the encounter location or the size of competing groups on the outcome. In addition, the identity of the intruder, whether familiar or stranger, may also play a role. To test whether the same factors affect the resident group's decisions already at the beginning of contests, we simulated intergroup encounters in banded mongooses (Mungos mungo). When spotting rival groups banded mongooses emit "screeching calls” which lead group members to bunch up. With playbacks of these calls, we tested how the groups' response was affected by the following factors: 1) the location of the playback in relation to their territory (exclusive use vs. overlap); 2) the number of resident individuals; and 3) the origin of calls (neighbor vs. stranger) used. Subjects were more likely to approach the loudspeakers and arrive within 1 m of the speakers in the exclusive use zone than in the overlap zone. Moreover, larger groups tended to be more likely to move toward the loudspeakers and were also more likely to arrive there. The origin of calls used in the playbacks did not affect the groups' responses. These findings exemplify the importance of the combined effect of location and group size on group decisions during impending intergroup contes
Changes in surface water drive the movements of Shoebills
Animal movement is mainly determined by spatial and temporal changes in resource availability. For wetland specialists, the seasonal availability of surface water may be a major determinant of their movement patterns. This study is the first to examine the movements of Shoebills (Balaeniceps rex), an iconic and vulnerable bird species. Using GPS transmitters deployed on six immature and one adult Shoebills over a 5-year period, during which four immatures matured into adults, we analyse their home ranges and distances moved in the Bangweulu Wetlands, Zambia. We relate their movements at the start of the rainy season (October to December) to changes in Normalized Difference Water Index (NDWI), a proxy for surface water. We show that Shoebills stay in the Bangweulu Wetlands all year round, moving less than 3 km per day on 81% of days. However, average annual home ranges were large, with high individual variability, but were similar between age classes. Immature and adult Shoebills responded differently to changes in surface water; sites that adults abandoned became drier, while sites abandoned by immatures became wetter. However, there were no differences in NDWI of areas used by Shoebills before abandonment and newly selected sites, suggesting that Shoebills select areas with similar surface water. We hypothesise that the different responses to changes in surface water by immature and adult Shoebills are related to age-specific optimal foraging conditions and fishing techniques. Our study highlights the need to understand the movements of Shoebills throughout their life cycle to design successful conservation actions for this emblematic, yet poorly known, species
Towards broad spectrum activity-based glycosidase probes: synthesis and evaluation of deoxygenated cyclophellitol aziridines
Activity-based protein profiling has emerged as a powerful tool for visualizing glycosidases in complex biological samples. Several configurational cyclophellitol isomers have been shown to display high selectivity as probes for glycosidases processing substrates featuring the same configuration. Here, a set of deoxygenated cyclophellitols are presented which enable inter-class profiling of [small beta]-glucosidases and [small beta]-galactosidases
An overview of activity-based probes for glycosidases
As the scope of modern genomics technologies increases, so does the need for informative chemical tools to study functional biology. Activity-based probes (ABPs) provide a powerful suite of reagents to probe the biochemistry of living organisms. These probes, featuring a specificity motif, a reactive chemical group and a reporter tag, are opening-up large swathes of protein chemistry to investigation in vitro, as well as in cellular extracts, cells and living organisms in vivo. Glycoside hydrolases, by virtue of their prominent biological and applied roles, provide a broad canvas on which ABPs may illustrate their functions. Here we provide an overview of glycosidase ABP mechanisms, and review recent ABP work in the glycoside hydrolase field, encompassing their use in medical diagnosis, their application for generating chemical genetic disease models, their fine-tuning through conformational and reactivity insight, their use for high-throughput inhibitor discovery, and their deployment for enzyme discovery and dynamic characterization.Medical BiochemistryBio-organic Synthesi
First steps toward harmonized human biomonitoring in Europe : demonstration project to perform human biomonitoring on a European scale
'Reproduced with permission from Environmental Health Perspectives'Background: For Europe as a whole, data on internal exposure to environmental chemicals do not
yet exist. Characterization of the internal individual chemical environment is expected to enhance
understanding of the environmental threats to health.
Objectives: We developed and applied a harmonized protocol to collect comparable human
biomonitoring data all over Europe.
Methods: In 17 European countries, we measured mercury in hair and cotinine, phthalate metabolites,
and cadmium in urine of 1,844 children (5–11 years of age) and their mothers. Specimens were collected
over a 5-month period in 2011–2012. We obtained information on personal characteristics, environment,
and lifestyle. We used the resulting database to compare concentrations of exposure biomarkers within
Europe, to identify determinants of exposure, and to compare exposure biomarkers with healthbased
guidelines.
Results: Biomarker concentrations showed a wide variability in the European population. However,
levels in children and mothers were highly correlated. Most biomarker concentrations were below the
health-based guidance values.
Conclusions: We have taken the first steps to assess personal chemical exposures in Europe as a whole.
Key success factors were the harmonized protocol development, intensive training and capacity building for
field work, chemical analysis and communication, as well as stringent quality control programs for chemical
and data analysis. Our project demonstrates the feasibility of a Europe-wide human biomonitoring
framework to support the decision-making process of environmental measures to protect public health.The research leading to these results received funding for the COPHES project (COnsortium to Perform Human biomonitoring on a European Scale) from the European Community’s Seventh Framework Programme [FP7/2007–2013] under grant agreement 244237. DEMOCOPHES (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) was co-funded (50%:50%) by the European Commission LIFE+ Programme (LIFE09/ENV/BE/000410) and the partners. For information on both projects as well as on the national co-funding institutions, see http://www.eu-hbm.info/. The sponsors had no role in the study design, data collection, data analysis, data interpretation or writing of the report
Polymer nanofilms with enhanced microporosity by interfacial polymerization
Highly permeable and selective membranes are desirable for energy-efficient gas and liquid separations. Microporous organic polymers have attracted significant attention in this respect owing to their high porosity, permeability, and molecular selectivity. However, it remains challenging to fabricate selective polymer membranes with controlled microporosity which are stable in solvents. Here we report a new approach to designing crosslinked, rigid polymer nanofilms with enhanced microporosity by manipulating the molecular structure. Ultra-thin polyarylate nanofilms with thickness down to 20 nm were formed in-situ by interfacial polymerisation. Enhanced microporosity and higher interconnectivity of intermolecular network voids, as rationalised by molecular simulations, are achieved by utilising contorted monomers for the interfacial polymerisation. Composite membranes comprising polyarylate nanofilms with enhanced microporosity fabricated in-situ on crosslinked polyimide ultrafiltration membranes show outstanding separation performance in organic solvents, with up to two orders of magnitude higher solvent permeance than membranes fabricated with nanofilms made from noncontorted planar monomers
The detection of a strong episignature for Chung–Jansen syndrome, partially overlapping with Börjeson–Forssman–Lehmann and White–Kernohan syndromes
Chung-Jansen syndrome is a neurodevelopmental disorder characterized by intellectual disability, behavioral problems, obesity and dysmorphic features. It is caused by pathogenic variants in the PHIP gene that encodes for the Pleckstrin homology domain-interacting protein, which is part of an epigenetic modifier protein complex. Therefore, we hypothesized that PHIP haploinsufficiency may impact genome-wide DNA methylation (DNAm). We assessed the DNAm profiles of affected individuals with pathogenic and likely pathogenic PHIP variants with Infinium Methylation EPIC arrays and report a specific and sensitive DNAm episignature biomarker for Chung–Jansen syndrome. In addition, we observed similarities between the methylation profile of Chung–Jansen syndrome and that of functionally related and clinically partially overlapping genetic disorders, White–Kernohan syndrome (caused by variants in DDB1 gene) and Börjeson–Forssman–Lehmann syndrome (caused by variants in PHF6 gene). Based on these observations we also proceeded to develop a common episignature biomarker for these disorders. These newly defined episignatures can be used as part of a multiclass episignature classifier for screening of affected individuals with rare disorders and interpretation of genetic variants of unknown clinical significance, and provide further insights into the common molecular pathophysiology of the clinically-related Chung–Jansen, Börjeson–Forssman–Lehmann and White–Kernohan syndromes.</p
Ethical leadership as antecedent of job satisfaction, affective organizational commitment and intention to stay among volunteers of non-profit organizations
The aim of this paper is to investigate among a group of non-profit organizations: (a)
the effect of ethical leadership (EL) on volunteers\u2019 satisfaction, affective organizational
commitment and intention to stay in the same organization; (b) the role played by job
satisfaction as a mediator in the relationship between EL and volunteers\u2019 intentions
to stay in the same organization, as well as between EL and affective commitment.
An anonymous questionnaire was individually administered to 198 Italian volunteers of
different non-profit organizations. The questionnaire contained the Ethical Leadership
Scale, the Volunteers Satisfaction Index, the Affective organization Scale, as well as
questions regarding the participants\u2019 age, sex, type of work, level of education, length
of their volunteer works, intention to volunteer in the following months in the same
organization. The construct as well the effects of EL on volunteers is approached in
light of the Social Exchange Theory and the Social Learning Theory. Structural equation
models were used to test hypothesized relationships. The results confirm the role of
mediation of volunteer satisfaction in the relationships between the variables studied.
In particular, EL was found to be positively associated both with volunteers\u2019 intention
of staying and with their affective commitment. In the first case this relationship is fully
explained by the mediation of the volunteers\u2019 satisfaction, while the latter is explained
by both direct and indirect factors. To the authors\u2019 knowledge, this the first attempt to
understand the role played by EL on volunteers\u2019 behavior and, more in general, in the
management of non-profit organizations. Findings are relevant both for practitioners and
managers of non-profit organization, since they suggest the relevance of the perception
of EL by volunteers, as well as for scholars, since they further deepen the knowledge
on EL and its effects on the followers. Limits of the study: the questionnaire was
administered only among a group of non-statistical sample of volunteers. Furthermore,
the study reached only volunteers from Italian non-profit organization
Cluster Headache Genomewide Association Study and Meta-Analysis Identifies Eight Loci and Implicates Smoking as Causal Risk Factor
Objective: The objective of this study was to aggregate data for the first genomewide association study meta-analysis of cluster headache, to identify genetic risk variants, and gain biological insights. Methods: A total of 4,777 cases (3,348 men and 1,429 women) with clinically diagnosed cluster headache were recruited from 10 European and 1 East Asian cohorts. We first performed an inverse-variance genomewide association meta-analysis of 4,043 cases and 21,729 controls of European ancestry. In a secondary trans-ancestry meta-analysis, we included 734 cases and 9,846 controls of East Asian ancestry. Candidate causal genes were prioritized by 5 complementary methods: expression quantitative trait loci, transcriptome-wide association, fine-mapping of causal gene sets, genetically driven DNA methylation, and effects on protein structure. Gene set and tissue enrichment analyses, genetic correlation, genetic risk score analysis, and Mendelian randomization were part of the downstream analyses. Results: The estimated single nucleotide polymorphism (SNP)-based heritability of cluster headache was 14.5%. We identified 9 independent signals in 7 genomewide significant loci in the primary meta-analysis, and one additional locus in the trans-ethnic meta-analysis. Five of the loci were previously known. The 20 genes prioritized as potentially causal for cluster headache showed enrichment to artery and brain tissue. Cluster headache was genetically correlated with cigarette smoking, risk-taking behavior, attention deficit hyperactivity disorder (ADHD), depression, and musculoskeletal pain. Mendelian randomization analysis indicated a causal effect of cigarette smoking intensity on cluster headache. Three of the identified loci were shared with migraine. Interpretation: This first genomewide association study meta-analysis gives clues to the biological basis of cluster headache and indicates that smoking is a causal risk factor
The trans-ancestral genomic architecture of glycemic traits
Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution. A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Peer reviewe
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