Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and ...assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.
Various bio-applications of mesoporous materials (
e.g.
, the immobilization of enzymes or the delivery of biomolecules such as siRNA) require large pores for the successful adsorption of the rather ...large molecules of interest and protecting the fragile cargo from external forces such as degradation. We describe the facile synthesis of functionalized mesoporous silica nanoparticles with large pores (LP-MSNs) providing high loading capacity for the immobilization of two differently-sized enzymes. The synthesis procedure yields homogeneous core-shell particles of about 100 nm in size with large mesopores (about 7 nm in diameter) and an azide-functionality inside the pores. The LP-MSNs were synthesized employing a co-condensation approach with the rather large micellar template cetyltrimethylammonium
p
-toluenesulfonate (CTATos). Due to the azide functionality, the LP-MSNs are suitable for bio-orthogonal click chemistry reactions within the porous network. Two different acetylene-functionalized enzymes (sp-carbonic anhydrase (CA) and sp-horseradish peroxidase (HRP)) were immobilized in the pores of the obtained LP-MSNs by a copper-catalyzed 1,3-dipolar cycloaddition reaction. The covalent attachment of the enzymes within the mesopores allowed us to investigate the catalytic performance of the enzyme-silica systems. The enzymes are stable after bioconjugation with the silica support and show high catalytic activity over several cycles for the colorimetric reaction of guaiacol (2-methoxyphenol) in case of LP-MSN-HRP and the hydrolysis of 4-nitrophenyl acetate (NPA) by LP-MSN-CA.
Carbonic anhydrase and horseradish peroxidase are immobilized inside the ordered material by click reactions. Colorimetric assays prove their catalytic activity.
Nowadays, the use of biomass increasingly replaces the fossil fuels for the domestic heating production. In order to reduce pollutant emissions from biomass combustion, wood was washed at room ...temperature in order to represent natural rain leaching before burning in a recent pellet stove (2010s) of nominal output of 6.3 kW. Raw and washed woods were combusted for three different types of wood (oak, beech and fir) and the study focused on their particulate and gaseous emissions (Total Suspended Particles (TSP), Particulate Matter with diameter below 2.5 μm (PM2.5), carbon monoxide (CO), nitrogen oxides (NOx) and Total Volatile Organic Compounds (TVOC)). Polycyclic Aromatic Hydrocarbons (PAH), aldehydes and wood tracers as phenols compounds were also measured. In addition, considering the toxic equivalent factor, the human health impact of adsorbed and gaseous PAH is considerably reduced (96%) in the case of washed fir combustion. Emission factors of CO and TSP for washed wood combustion also show a decrease up to 50% depending on the type of wood used. Furthermore, phenolic compounds, Benzene, Toluene, Ethylbenzene, Xylenes and Trimethylbenzene (BTEXT) emissions can also be reduced by the washing of biomass. Washed oak combustion leads to a clear decrease by 60% of the total of BTEXT. In the case of phenols emissions, phenol shows a significant decrease by 91% during the combustion of washed fir wood.
•Combustion of several species of wood pellets in a pellet stove•Influence of the leaching on gaseous and particulate pollutants•Speciation of organic compounds in PM emitted during energy recovery in a domestic pellet stove•Size fractionation of PM2.5 by Electrical Low Pressure Impactor
In the original published article, some of the symbols in figure 1A were modified incorrectly during the typesetting and publication process. The correct version of the figure is provided in this ...correction
Impaired tool use despite preserved basic motor functions occurs after stroke in the context of apraxia, a cognitive motor disorder. To elucidate the neuroanatomical underpinnings of different tool ...use deficits, prospective behavioral assessments of 136 acute left-hemisphere stroke patients were combined with lesion delineation on magnetic resonance imaging (MRI) images for voxel-based lesion-symptom mapping. Deficits affecting both the selection of the appropriate recipient for a given tool (ToolSelect, e.g., choosing the nail for the hammer), and the performance of the typical tool-associated action (ToolUse, e.g., hammering in the nail) were associated with ventro-dorsal stream lesions, particularly within inferior parietal lobule. However, ToolSelect compared with ToolUse deficits were specifically related to damage within ventral stream regions including anterior temporal lobe. Additional retrospective error dichotomization based on the videotaped performances of ToolUse revealed that spatio-temporal errors (movement errors) were mainly caused by inferior parietal damage adjacent to the intraparietal sulcus while content errors, that is, perplexity, unrecognizable, or semantically incorrect movements, resulted from lesions within supramarginal gyrus and superior temporal lobe. In summary, our results suggest that in the use of tools, conceptual and production-related aspects can be differentiated and are implemented in anatomically distinct streams.
Most birds incubate their eggs, which requires time and energy at the expense of other activities. Birds generally have two incubation strategies: biparental where both mates cooperate in incubating ...eggs, and uniparental where a single parent incubates. In harsh and unpredictable environments, incubation is challenging due to high energetic demands and variable resource availability.
We studied the relationships between the incubation behaviour of sandpipers (genus Calidris) and two environmental variables: temperature and a proxy of primary productivity (i.e. NDVI). We investigated how these relationships vary between incubation strategies and across species among strategies. We also studied how the relationship between current temperature and incubation behaviour varies with previous day's temperature.
We monitored the incubation behaviour of nine sandpiper species using thermologgers at 15 arctic sites between 2016 and 2019. We also used thermologgers to record the ground surface temperature at conspecific nest sites and extracted NDVI values from a remote sensing product.
We found no relationship between either environmental variables and biparental incubation behaviour. Conversely, as ground-surface temperature increased, uniparental species decreased total duration of recesses (TDR) and mean duration of recesses (MDR), but increased number of recesses (NR). Moreover, small species showed stronger relationships with ground-surface temperature than large species. When all uniparental species were combined, an increase in NDVI was correlated with higher mean duration, total duration and number of recesses, but relationships varied widely across species. Finally, some uniparental species showed a lag effect with a higher nest attentiveness after a warm day while more recesses occurred after a cold day than was predicted based on current temperatures.
We demonstrate the complex interplay between shorebird incubation strategies, incubation behaviour, and environmental conditions. Understanding how species respond to changes in their environment during incubation helps predict their future reproductive success.
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•We used ground-surface temperature and a primary productivity index to describe environmental conditions.•Most biparental species showed no relationship between incubation behaviour and environmental conditions.•Uniparental species showed a higher attentiveness, shorter and more frequent recesses in warm than in cold conditions.•Relationships found between uniparental species’ incubation behaviour and temperature vary with primary productivity.•We found lag effects of past temperature, supporting the hypothesis that some species use their reserves during cold days.
Abstract
Fluorescent ligands are versatile tools for the study of G protein-coupled receptors. Depending on the fluorophore, they can be used for a range of different applications, including ...fluorescence microscopy and bioluminescence or fluorescence resonance energy transfer (BRET or FRET) assays. Starting from phenylpiperazines and indanylamines, privileged scaffolds for dopamine D
2
-like receptors, we developed dansyl-labeled fluorescent ligands that are well accommodated in the binding pockets of D
2
and D
3
receptors. These receptors are the target proteins for the therapy for several neurologic and psychiatric disorders, including Parkinson’s disease and schizophrenia. The dansyl-labeled ligands exhibit binding affinities up to 0.44 nM and 0.29 nM at D
2
R and D
3
R, respectively. When the dansyl label was exchanged for sterically more demanding xanthene or cyanine dyes, fluorescent ligands 10a-c retained excellent binding properties and, as expected from their indanylamine pharmacophore, acted as agonists at D
2
R. While the Cy3B-labeled ligand 10b was used to visualize D
2
R and D
3
R on the surface of living cells by total internal reflection microscopy, ligand 10a comprising a rhodamine label showed excellent properties in a NanoBRET binding assay at D
3
R.
Previous lesion studies suggest that semantic and phonological fluency are differentially subserved by distinct brain regions in the left temporal and the left frontal cortex, respectively. However, ...as of yet, this often implied double dissociation has not been explicitly investigated due to mainly two reasons: (i) the lack of sufficiently large samples of brain-lesioned patients that underwent assessment of the two fluency variants and (ii) the lack of tools to assess interactions in factorial analyses of non-normally distributed behavioral data. In addition, previous studies did not control for task resource artifacts potentially introduced by the generally higher task difficulty of phonological compared to semantic fluency. We addressed these issues by task-difficulty adjusted assessment of semantic and phonological fluency in 85 chronic patients with ischemic stroke of the left middle cerebral artery. For classical region-based lesion-behavior mapping patients were grouped with respect to their primary lesion location. Building on the extension of the non-parametric Brunner-Munzel rank-order test to multi-factorial designs, ANOVA-type analyses revealed a significant two-way interaction for cue type (semantic vs. phonological) by lesion location (left temporal vs. left frontal vs. other as stroke control group). Subsequent contrast analyses further confirmed the proposed double dissociation by demonstrating that (i) compared to stroke controls, left temporal lesions led to significant impairments in semantic but not in phonological fluency, whereas left frontal lesions led to significant impairments in phonological but not in semantic fluency, and that (ii) patients with frontal lesions showed significantly poorer performance in phonological than in semantic fluency, whereas patients with temporal lesions showed significantly poorer performance in semantic than in phonological fluency. The anatomical specificity of these findings was further assessed in voxel-based lesion-behavior mapping analyses using the multi-factorial extension of the Brunner-Munzel test. Voxel-wise ANOVA-type analyses identified circumscribed parts of left inferior frontal gyrus and left superior and middle temporal gyrus that significantly double-dissociated with respect to their differential contribution to phonological and semantic fluency, respectively. Furthermore, a main effect of lesion with significant impairments in both fluency types was found in left inferior frontal regions adjacent to but not overlapping with those showing the differential effect for phonological fluency. The present study hence not only provides first explicit evidence for the anatomical double dissociation in verbal fluency at the group level but also clearly underlines that its formulation constitutes an oversimplification as parts of left frontal cortex appear to contribute to both semantic and phonological fluency.
Multifunctional mesoporous silica nanoparticles (MSN) have attracted substantial attention with regard to their high potential for targeted drug delivery. For future clinical applications it is ...crucial to address safety concerns and understand the potential immunotoxicity of these nanoparticles. In this study, we assess the biocompatibility and functionality of multifunctional MSN in freshly isolated, primary murine immune cells. We show that the functionalized silica nanoparticles are rapidly and efficiently taken up into the endosomal compartment by specialized antigen-presenting cells such as dendritic cells. The silica nanoparticles showed a favorable toxicity profile and did not affect the viability of primary immune cells from the spleen in relevant concentrations. Cargo-free MSN induced only very low immune responses in primary cells as determined by surface expression of activation markers and release of pro-inflammatory cytokines such as Interleukin-6, -12 and -1β. In contrast, when surface-functionalized MSN with a pH-responsive polymer capping were loaded with an immune-activating drug, the synthetic Toll-like receptor 7 agonist R848, a strong immune response was provoked. We thus demonstrate that MSN represent an efficient drug delivery vehicle to primary immune cells that is both non-toxic and non-inflammagenic, which is a prerequisite for the use of these particles in biomedical applications.
Mesoporous silica nanoparticles represent an efficient drug delivery vehicle to primary immune cells that is both non-toxic and non-inflammagenic.
After birth, the immune system matures via interactions with microbes in the gut. The S100 calcium binding proteins S100A8 and S100A9, and their extracellular complex form, S100A8–A9, are found in ...high amounts in human breast milk. We studied levels of S100A8–A9 in fecal samples (also called fecal calprotectin) from newborns and during infancy, and their effects on development of the intestinal microbiota and mucosal immune system.
We collected stool samples (n = 517) from full-term (n = 72) and preterm infants (n = 49) at different timepoints over the first year of life (days 1, 3, 10, 30, 90, 180, and 360). We measured levels of S100A8–A9 by enzyme-linked immunosorbent assay and analyzed fecal microbiomes by 16S sRNA gene sequencing. We also obtained small and large intestine biopsies from 8 adults and 10 newborn infants without inflammatory bowel diseases (controls) and 8 infants with necrotizing enterocolitis and measured levels of S100A8 by immunofluorescence microscopy. Children were followed for 2.5 years and anthropometric data and medical information on infections were collected. We performed studies with newborn C57BL/6J wild-type and S100a9–/– mice (which also lack S100A8). Some mice were fed or given intraperitoneal injections of S100A8 or subcutaneous injections of Staphylococcus aureus. Blood and intestine, mesenterial and celiac lymph nodes were collected; cells and cytokines were measured by flow cytometry and studied in cell culture assays. Colon contents from mice were analyzed by culture-based microbiology assays.
Loss of S100A8 and S100A9 in mice altered the phenotypes of colonic lamina propria macrophages, compared with wild-type mice. Intestinal tissues from neonatal S100-knockout mice had reduced levels of CX3CR1 protein, and Il10 and Tgfb1 mRNAs, compared with wild-type mice, and fewer T-regulatory cells. S100-knockout mice weighed 21% more than wild-type mice at age 8 weeks and a higher proportion developed fatal sepsis during the neonatal period. S100-knockout mice had alterations in their fecal microbiomes, with higher abundance of Enterobacteriaceae. Feeding mice S100 at birth prevented the expansion of Enterobacteriaceae, increased numbers of T-regulatory cells and levels of CX3CR1 protein and Il10 mRNA in intestine tissues, and reduced body weight and death from neonatal sepsis. Fecal samples from term infants, but not preterm infants, had significantly higher levels of S100A8–A9 during the first 3 months of life than fecal samples from adults; levels decreased to adult levels after weaning. Fecal samples from infants born by cesarean delivery had lower levels of S100A8–A9 than from infants born by vaginal delivery. S100 proteins were expressed by lamina propria macrophages in intestinal tissues from infants, at higher levels than in intestinal tissues from adults. High fecal levels of S100 proteins, from 30 days to 1 year of age, were associated with higher abundance of Actinobacteria and Bifidobacteriaceae, and lower abundance of Gammaproteobacteria—particularly opportunistic Enterobacteriaceae. A low level of S100 proteins in infants’ fecal samples associated with development of sepsis and obesity by age 2 years.
S100A8 and S100A9 regulate development of the intestinal microbiota and immune system in neonates. Nutritional supplementation with these proteins might aide in development of preterm infants and prevent microbiota-associated disorders in later years.
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