Age- and trait-dependent breeding responses to environmental variation in a short-lived songbird

Breeding responses of organisms to environmental changes may profoundly depend on an individual's age, as an age-environment interaction may be expected to affect the expression of reproductive traits. However, little is known about how this interaction affects short-lived species that experience various environmental conditions in adulthood. Here, we used a 32-year dataset from the collared flycatcher, Ficedula albicollis, population to test whether and how the environment interacts with age to shape female age-specific reproduction. To characterise environmental variation, we applied the remotely sensed normalised difference vegetation index (NDVI), estimating vegetation productivity, and used it as a surrogate for habitat quality. Then, we analysed how within-individual age and NDVI determine patterns in laying date, clutch size, offspring production, and recruitment. We found that young and old females, but not middle-aged females, breeding under low NDVI started to lay eggs later and produced smaller clutches than females of the same age breeding under higher NDVI. No such effects were observed for offspring production or recruitment. Our study provides evidence that both an individual's age and the environmental variation experienced during adulthood may be crucial for shaping reproductive patterns in short-lived avian species, as has been found in long-lived birds.

Using citizen science to identify environmental correlates of bird-window collisions in Poland

Bird collisions with windows are among the highest sources of human caused mortality to this group of animals. However, environmental correlates of spatial patterns in collision risk are poorly understood, thus making mitigation measures difficult to implement. We took advantage of Covid-19 lockdown in the spring of 2020, when people were obligated to stay mainly at home, and performed a memory-recall questionnaire survey concerning bird-window collisions in Poland. We received information on bird-window collisions with 1800 buildings across the whole country accompanied by characteristics of each building, its vicinity and resident's behavior (time spent home, window cleaning). We supplemented these data with landscape description and performed statistical models to estimate importance of 13 explanatory variables as predictors of number of bird-window collisions. Reported number of collisions increased with the share of forests and arable land within 2 km of the building, and with proximity to rivers. Number of collisions also increased when single trees were close to buildings. More collisions were reported for houses than for flats and for new buildings than for old ones. Reported number of collisions increased with window cleaning which might suggest that cleaning reduces glass visibility for birds. As bird-window collision risk is highly variable among buildings but can be reduced with several measures improving glass visibility for birds, we recommend to use predictive models to identify collision hotspots for applying these measures. New houses located near rivers, in forests or agricultural landscapes have highest collision risk, and trees near buildings, often planted to benefit birds, can additionally elevate collision rate, thus potentially creating ecological traps. In such collision hotspots, reduction of window cleaning frequency can be considered as a mitigation measure unless the visual markers improving glass visibility for birds are installed on the panels.

The use of socio-economy in species distribution modelling: Features of rural societies improve predictions of barn owl occurrence

Variation of habitats and resources important for farmland birds seems to be only partly captured by ordinary statistics on land-use and agricultural production. For instance, densities of rodents being prey for owls and raptors or structures of rural architecture providing nesting sites for many species are central for bird diversity but are not reported in any official statistics. Thus, modelling species distributions, population abundance and trends of farmland birds may miss important predictive habitat elements. Here, we involve local socio-economy factors as a source of additional information on rural habitat to test whether it improves predictions of barn owl occurrence in 2768 churches across Poland. Barn owls occurred in 778 churches and seemed to prefer old churches made of brick located in regions with a milder climate, higher share of arable land and pastures, low road density and low levels of light pollution. Including data on local unemployment, the proportion of elder citizens, commune income per citizen, the share of citizens with high education and share of farmers among working population improved the model substantially and some of these variables predicted barn owl occurrence better than several land-use and climate data. Barn owls were more likely to occur in areas with high unemployment, a higher proportion of older citizens in a local population and higher share of farmers among working population. Importantly, the socio-economy variables were correlated with the barn owl occurrence despite all climatic, infrastructure and land-use data were present in the model. We conclude that the socio-economy of local societies may add important but overlooked information that links to spatial variation in farmland biodiversity.

Spatial patterns of bat diversity overlap with woodpecker abundance

Woodpecker diversity is usually higher in natural forests rich in dead wood and old trees than in managed ones, thus this group of birds is regarded as an indicator of forest biodiversity. Woodpeckers excavate cavities which can be subsequently used by several bird species. As a consequence, their abundance indicates high avian abundance and diversity in forests. However, woodpecker-made holes may be also important for other animals, for example, mammals but it has seldom been investigated so far. Here, we examine how well one species, the Great Spotted Woodpecker, predicts species richness, occurrence and acoustic activity of bats in Polish pine forests. In 2011 we conducted woodpecker and bat surveys at 63 point-count sites in forests that varied in terms of stand age, structure and amount of dead wood. From zero to five Great Spotted Woodpeckers at a point-count site were recorded. The total duration of the echolocation calls during a 10-min visit varied from 0 to 542 s and the number of bat species/species groups recorded during a visit ranged between zero to five. The local abundance of the woodpecker was positively correlated with bat species richness (on the verge of significance), bat occurrence and pooled bat activity. The occurrence of Eptesicus and Vespertilio bats and Nyctalus species was positively related with the abundance of the Great Spotted Woodpecker. The activity of Pipistrellus pygmaeus, Eptesicus and Vespertilio bats and a group of Myotis species was not associated with the woodpecker abundance, but echolocation calls of Nyctalus species, P. nathusii and P.pipistrellus were more often at sites with many Great Spotted Woodpeckers. Moreover, the probability of bat presence and the activity of bats was generally higher shortly after dusk and in middle of the summer than in late spring. We suggest that the observed correlations can be driven by similar roosting habitats (e.g., woodpeckers can provide breeding cavities for bats) or possibly by associated invertebrate food resources of woodpeckers and bats. The abundance of Great Spotted Woodpecker seems to be a good positive indicator of bat species richness, occurrence and activity, thus adding a group of relatively cryptic forest species that are indicated by the presence of the Great Spotted Woodpecker.

The impact of exercise training and resveratrol supplementation on gut microbiota composition in high-fat diet fed mice

The aim of this study was to examine the effect of exercise training and dietary supplementation of resveratrol on the composition of gut microbiota and to test the hypothesis that exercise training and resveratrol can prevent high-fat diet (HFD)-induced changes in the gut microbiota. Mice fed a HFD supplemented with resveratrol (4 g/kg food) were protected against diet-induced obesity, while exercise trained HFD-fed animals (running on average 50 km/week) were not. Dietary resveratrol supplementation induced changes predominantly in the low-abundant bacteria, while exercise training induced changes in the high-abundant bacteria in the gut as analyzed by ADONIS test with Weighted UniFrac distances. Interestingly, the two interventions affected the gut microbiome independently of the inflammatory state of the HFD-fed animals as assessed by the systemic serum amyloid A levels. These results suggest that both resveratrol supplementation and regular physical activity modulate the composition of murine microbiota independently of the systemic inflammatory state. Moreover, the effects of exercise training on the microbiota seem to occur without changes in adiposity, while resveratrol-mediated alterations may relate to adipose tissue mass.

Lingonberries alter the gut microbiota and prevent low-grade inflammation in high-fat diet fed mice

Background

The gut microbiota plays an important role in the development of obesity and obesity-associated impairments such as low-grade inflammation. Lingonberries have been shown to prevent diet-induced obesity and low-grade inflammation. However, it is not known whether the effect of lingonberry supplementation is related to modifications of the gut microbiota. The aim of the present study was to describe whether consumption of different batches of lingonberries alters the composition of the gut microbiota, which could be relevant for the protective effect against high fat (HF)-induced metabolic alterations.

Methods

Three groups of C57BL/6J mice were fed HF diet with or without a supplement of 20% lingonberries from two different batches (Lingon1 and Lingon2) during 11 weeks. The composition and functionality of the cecal microbiota were assessed by 16S rRNA sequencing and PICRUSt. In addition, parameters related to obesity, insulin sensitivity, hepatic steatosis, inflammation and gut barrier function were examined.

Results

HF-induced obesity was only prevented by the Lingon1 diet, whereas both batches of lingonberries reduced plasma levels of markers of inflammation and endotoxemia (SAA and LBP) as well as modified the composition and functionality of the gut microbiota, compared to the HF control group. The relative abundance of Akkermansia and Faecalibacterium, genera associated with healthy gut mucosa and anti-inflammation, was found to increase in response to lingonberry intake.

Conclusions

Our results show that supplementation with lingonberries to an HF diet prevents low-grade inflammation and is associated with significant changes of the microbiota composition. Notably, the anti-inflammatory properties of lingonberries seem to be independent of effects on body weight gain.

ApoA-I Milano stimulates lipolysis in adipose cells independently of cAMP/PKA activation

ApoA-I, the main protein component of HDL, is suggested to be involved in metabolic homeostasis. We examined the effects of Milano, a naturally occurring ApoA-I variant, about which little mechanistic information is available. Remarkably, high-fat-fed mice treated with Milano displayed a rapid weight loss greater than ApoA-I WT treated mice, and a significantly reduced adipose tissue mass, without an inflammatory response. Further, lipolysis in adipose cells isolated from mice treated with either WT or Milano was increased. In primary rat adipose cells, Milano stimulated cholesterol efflux and increased glycerol release, independently of β-adrenergic stimulation and phosphorylation of hormone sensitive lipase (Ser563) and perilipin (Ser522). Stimulation with Milano had a significantly greater effect on glycerol release compared with WT but similar effect on cholesterol efflux. Pharmacological inhibition or siRNA silencing of ABCA1 did not diminish Milano-stimulated lipolysis, although binding to the cell surface was decreased, as analyzed by fluorescence microscopy. Interestingly, methyl-β-cyclodextrin, a well-described cholesterol acceptor, dose-dependently stimulated lipolysis. Together, these results suggest that decreased fat mass and increased lipolysis following Milano treatment in vivo is partly explained by a novel mechanism at the adipose cell level comprising stimulation of lipolysis independently of the canonical cAMP/protein kinase A signaling pathway.

A catalog of the mouse gut metagenome

We established a catalog of the mouse gut metagenome comprising ∼2.6 million nonredundant genes by sequencing DNA from fecal samples of 184 mice. To secure high microbiome diversity, we used mouse strains of diverse genetic backgrounds, from different providers, kept in different housing laboratories and fed either a low-fat or high-fat diet. Similar to the human gut microbiome, >99% of the cataloged genes are bacterial. We identified 541 metagenomic species and defined a core set of 26 metagenomic species found in 95% of the mice. The mouse gut microbiome is functionally similar to its human counterpart, with 95.2% of its Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologous groups in common. However, only 4.0% of the mouse gut microbial genes were shared (95% identity, 90% coverage) with those of the human gut microbiome. This catalog provides a useful reference for future studies.

Polyacetylenes from carrots (Daucus carota) improve glucose uptake in vitro in adipocytes and myotubes

Falcarinol and falcarindiol isolated from a carrot extract stimulate glucose uptake in adipocytes and myotubes, and may represent scaffolds for novel partial PPARγ agonists.

Isomeric C12-alkamides from the roots of Echinacea purpurea improve basal and insulin-dependent glucose uptake in 3T3-L1 adipocytes

Echinacea purpurea has been used in traditional medicine as a remedy for the treatment and prevention of upper respiratory tract infections and the common cold. Recent investigations have indicated that E. purpurea also has an effect on insulin resistance. A dichloromethane extract of E. purpurea roots was found to enhance glucose uptake in adipocytes and to activate peroxisome proliferator-activated receptor γ. The purpose of the present study was to identify the bioactive compounds responsible for the potential antidiabetic effect of the dichloromethane extract using a bioassay-guided fractionation approach. Basal and insulin-dependent glucose uptake in 3T3-L1 adipocytes were used to assess the bioactivity of extract, fractions and isolated metabolites. A peroxisome proliferator-activated receptor γ transactivation assay was used to determine the peroxisome proliferator-activated receptor γ activating properties of the extract, active fractions and isolated metabolites. Two novel isomeric dodeca-2E,4E,8Z,10E/Z-tetraenoic acid 2-methylbutylamides together with two known C12-alkamides and α-linolenic acid were isolated from the active fractions. The isomeric C12-alkamides were found to activate peroxisome proliferator-activated receptor γ, to increase basal and insulin-dependent glucose uptake in adipocytes in a dose-dependent manner, and to exhibit characteristics of a peroxisome proliferator-activated receptor γ partial agonist.

2-(2-Bromophenyl)-formononetin and 2-heptyl-formononetin are PPARγ partial agonists and reduce lipid accumulation in 3T3-L1 adipocytes

Isoflavones are bioactive compounds that have been shown to decrease lipid accumulation in vitro. However, the knowledge of the isoflavone formononetin is limited. The aim of the study was to assess the effects of formononetin and its two synthetic analogues, 2-(2-bromophenyl)-formononetin and 2-heptyl-formononetin, on lipid accumulation in 3T3-L1 adipocytes and investigate possible mechanisms. Formononetin and the two analogues were added day 0-8 or day 8-10 of the differentiation period, and lipid accumulation, glycerol release and gene expression were measured. Additionally, competitive peroxisome proliferator-activated receptor (PPAR)-γ binding assay, PPARγ transactivation assay and Western blot for phosphorylated AMP-activated protein kinase (AMPK) were performed. Chronic treatment (day 0-8) with formononetin increased lipid accumulation, whereas the two analogues decreased lipid accumulation partly due to decreased differentiation. The two analogues, but not formononetin, also decreased lipid content in mature adipocytes. 2-Heptyl-formononetin increased glycerol release and lipolytic gene expression and decreased lipogenic gene expression. Formononetin did not bind to or activate PPARγ whereas both analogues bound to the receptor and behaved as PPARγ partial agonists in the transactivation assay. Neither of the compounds affected phosphorylation of AMPK. In conclusion, the analogues of formononetin decreased lipid accumulation possibly in part by acting as PPARγ partial agonists.

Profiling of lipid species by normal-phase liquid chromatography, nanoelectrospray ionization, and ion trap-orbitrap mass spectrometry

Detailed analysis of lipid species can be challenging due to their structural diversity and wide concentration range in cells, tissues, and biofluids. To address these analytical challenges, we devised a reproducible, sensitive, and integrated lipidomics workflow based on normal-phase liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) and LC-ITMS(2) (ion trap tandem mass spectrometry) for profiling and structural analysis of lipid species. The workflow uses a normal-phase LC system for efficient separation of apolar and polar lipid species combined with sensitive and specific analysis powered by a chip-based nanoelectrospray ion source and a hybrid ion trap-orbitrap mass spectrometer. The workflow was executed using a primary LC-FTMS survey routine for identification and profiling of lipid species based on high-mass accuracy and retention time followed by a targeted LC-ITMS(2) routine for characterizing the fatty acid moieties of identified lipid species. We benchmarked the performance of the workflow by characterizing the chromatographic properties of the LC-MS system for general lipid analysis. In addition, we demonstrate the efficacy of the workflow by reporting a study of low-abundant triacylglycerol and ceramide species in mouse brain cerebellum and 3T3-L1 adipocytes, respectively. The workflow described here is generic and can be extended for detailed lipid analysis of sample matrices having a wide range of lipid compositions.

Activation of the nuclear receptor PPARγ by metabolites isolated from sage (Salvia officinalis L.)

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia officinalis has been used as a traditional remedy against diabetes in many countries and its glucose-lowering effects have been demonstrated in animal studies. The active compounds and their possible mode of action are still unknown although it has been suggested that diterpenes may be responsible for the anti-diabetic effect of Salvia officinalis.

AIM OF THE STUDY

To investigate whether the reported anti-diabetic effects of Salvia officinalis are related to activation of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)γ and to identify the bioactive constituents.

MATERIALS AND METHODS

From a dichloromethane extract of Salvia officinalis able to activate PPARγ several major metabolites were isolated by chromatographic techniques. To assess bioactivity of the isolated metabolites a PPARγ transactivation assay was used.

RESULTS

Eight diterpenes were isolated and identified including a new abietane diterpene being the epirosmanol ester of 12-O-methyl carnosic acid and 20-hydroxyferruginol, which was isolated from Salvia officinalis for the first time, as well as viridiflorol, oleanolic acid, and α-linolenic acid. 12-O-methyl carnosic acid and α-linolenic acid were able to significantly activate PPARγ whereas the remaining metabolites were either unable to activate PPARγ or yielded insignificant activation.

CONCLUSIONS

Selected metabolites from Salvia officinalis were able to activate PPARγ and hence, the anti-diabetic activity of this plant could in part be mediated through this nuclear receptor.