Experience-dependent emergence of a grouping bias

Humans share with non-human animals perceptual biases that might form the basis of complex cognitive abilities. One example comes from the principles described by the iambic–trochaic law (ITL). According to the ITL, sequences of sounds varying in duration are grouped as iambs, whereas sequences varying in intensity are grouped as trochees. These grouping biases have gained much attention because they might help pre-lexical infants bootstrap syntactic parameters (such as word order) in their language. Here, we explore how experience triggers the emergence of perceptual grouping biases in a non-human species. We familiarized rats with either long–short or short–long tone pairs. We then trained the animals to discriminate between sequences of alternating and randomly ordered tones. Results showed animals developed a grouping bias coherent with the exposure they had. Together with results observed in human adults and infants, these results suggest that experience modulates perceptual organizing principles that are present across species.     

Culture–gene coevolution of individualism–collectivism and the serotonin transporter gene

Culture–gene coevolutionary theory posits that cultural values have evolved, are adaptive and influence the social and physical environments under which genetic selection operates. Here, we examined the association between cultural values of individualism–collectivism and allelic frequency of the serotonin transporter functional polymorphism (5-HTTLPR) as well as the role this culture–gene association may play in explaining global variability in prevalence of pathogens and affective disorders. We found evidence that collectivistic cultures were significantly more likely to comprise individuals carrying the short (S) allele of the 5-HTTLPR across 29 nations. Results further show that historical pathogen prevalence predicts cultural variability in individualism–collectivism owing to genetic selection of the S allele. Additionally, cultural values and frequency of S allele carriers negatively predict global prevalence of anxiety and mood disorder. Finally, mediation analyses further indicate that increased frequency of S allele carriers predicted decreased anxiety and mood disorder prevalence owing to increased collectivistic cultural values. Taken together, our findings suggest culture–gene coevolution between allelic frequency of 5-HTTLPR and cultural values of individualism–collectivism and support the notion that cultural values buffer genetically susceptible populations from increased prevalence of affective disorders. Implications of the current findings for understanding culture–gene coevolution of human brain and behaviour as well as how this coevolutionary process may contribute to global variation in pathogen prevalence and epidemiology of affective disorders, such as anxiety and depression, are discussed.     

Missing the rarest: is the positive interspecific abundance–distribution relationship a truly general macroecological pattern?

Lepidopterists have long acknowledged that many uncommon butterfly species can be extremely abundant in suitable locations. If this is generally true, it contradicts the general macroecological pattern of the positive interspecific relationship between abundance and distribution, i.e. locally abundant species are often geographically more widespread than locally rare species. Indeed, a negative abundance–distribution relationship has been documented for butterflies in Finland. Here we show, using the Finnish butterflies as an example, that a positive abundance–distribution relationship results if the geographically restricted species are missed, as may be the case in studies based on random or restricted sampling protocols, or in studies that are conducted over small spatial scales. In our case, the abundance–distribution relationship becomes negative when approximately 70 per cent of the species are included. This observation suggests that the abundance–distribution relationship may in fact not be linear over the entire range of distributions. This intriguing possibility combined with some taxonomic biases in the literature may undermine the generalization that for a given taxonomic assemblage there is a positive interspecific relationship between local abundance and regional distribution.     

Therapeutic Anti-Depressant Potential of Microbial GABA Produced by Lactobacillus rhamnosus Strains for GABAergic Signaling Restoration and Inhibition of Addiction-Induced HPA Axis Hyperactivity

The role of the microbiota–gut–brain (MGB) axis in mood regulation and depression treatment has gained attention in recent years, as evidenced by the growing number of animal and human studies that have reported the anti-depressive and associated gamma-aminobutyric acid-ergic (GABAergic) effects of probiotics developed from Lactobacillus rhamnosus bacterial strains in the gut microbiome. The depressive states attenuated by these probiotics in patients suffering from clinical depression also characterize the severe and relapse-inducing withdrawal phase of the addiction cycle, which has been found to arise from the intoxication-enabled hyperregulation of the hypothalamic–pituitary–adrenal (HPA) axis, the body’s major stress response system, and a corresponding attenuation of its main inhibitory system, the gamma-aminobutyric acid (GABA) signaling system. Therefore, the use of probiotics in the treatment of general cases of depression provides hope for a novel therapeutic approach to withdrawal depression remediation. This review discusses potential therapeutic avenues by which probiotic application of Lactobacillus rhamnosus strains can be used to restore the central GABAergic activity responsible for attenuating the depression-inducing HPA axis hyperactivity in addiction withdrawal. Also, information is provided on brain GABAergic signaling from other known GABA-producing strains of gut microbiota.     

Influence of environmental conditions at spawning sites and migration routes on adaptive variation and population connectivity in Chinook salmon

Many species that undergo long breeding migrations, such as anadromous fishes, face highly heterogeneous environments along their migration corridors and at their spawning sites. These environmental challenges encountered at different life stages may act as strong selective pressures and drive local adaptation. However, the relative influence of environmental conditions along the migration corridor compared with the conditions at spawning sites on driving selection is still unknown. In this study, we performed genome–environment associations (GEA) to understand the relationship between landscape and environmental conditions driving selection in seven populations of the anadromous Chinook salmon (Oncorhynchus tshawytscha)—a species of important economic, social, cultural, and ecological value—in the Columbia River basin. We extracted environmental variables for the shared migration corridors and at distinct spawning sites for each population, and used a Pool‐seq approach to perform whole genome resequencing. Bayesian and univariate GEA tests with migration‐specific and spawning site‐specific environmental variables indicated many more candidate SNPs associated with environmental conditions at the migration corridor compared with spawning sites. Specifically, temperature, precipitation, terrain roughness, and elevation variables of the migration corridor were the most significant drivers of environmental selection. Additional analyses of neutral loci revealed two distinct clusters representing populations from different geographic regions of the drainage that also exhibit differences in adult migration timing (summer vs. fall). Tests for genomic regions under selection revealed a strong peak on chromosome 28, corresponding to the GREB1L/ROCK1 region that has been identified previously in salmonids as a region associated with adult migration timing. Our results show that environmental variation experienced throughout migration corridors imposed a greater selective pressure on Chinook salmon than environmental conditions at spawning sites.     

Effects of social organization and elevation on spatial genetic structure in a montane ant

Studying patterns of population structure across the landscape sheds light on dispersal and demographic processes, which helps to inform conservation decisions. Here, we study how social organization and landscape factors affect spatial patterns of genetic differentiation in an ant species living in mountainous regions. Using genome‐wide SNP markers, we assess population structure in the Alpine silver ant, Formica selysi. This species has two social forms controlled by a supergene. The monogyne form has one queen per colony, while the polygyne form has multiple queens per colony. The two social forms co‐occur in the same populations. For both social forms, we found a strong pattern of isolation‐by‐distance across the Alps. Within regions, genetic differentiation between populations was weaker for the monogyne form than for the polygyne form. We suggest that this pattern is due to higher dispersal and effective population sizes in the monogyne form. In addition, we found stronger isolation‐by‐distance and lower genetic diversity in high elevation populations, compared to lowland populations, suggesting that gene flow between F. selysi populations in the Alps occurs mostly through riparian corridors along lowland valleys. Overall, this survey highlights the need to consider intraspecific polymorphisms when assessing population connectivity and calls for special attention to the conservation of lowland habitats in mountain regions.     

Bumblebees moving up: shifts in elevation ranges in the Pyrenees over 115 years

In a warming climate, species are expected to shift their geographical ranges to higher elevations and latitudes, and if interacting species shift at different rates, networks may be disrupted. To quantify the effects of ongoing climate change, repeating historical biodiversity surveys is necessary. In this study, we compare the distribution of a plant–pollinator community between two surveys 115 years apart (1889 and 2005–06), reporting distribution patterns and changes observed for bumblebee species and bumblebee-visited plants in the Gavarnie-Gèdre commune in the Pyrenees, located in southwest Europe at the French–Spanish border. The region has warmed significantly over this period, alongside shifts in agricultural land use and forest. The composition of the bumblebee community shows relative stability, but we observed clear shifts to higher elevations for bumblebees (averaging 129 m) and plants (229 m) and provide preliminary evidence that some bumblebee species shift with the plants they visit. We also observe that some species have been able to occupy the same climate range in both periods by shifting elevation range. The results suggest the need for long-term monitoring to determine the role and impact of the different drivers of global change, especially in montane habitats where the impacts of climate changes are anticipated to be more extreme.     

No post-Cretaceous ecosystem depression in European forests? Rich insect-feeding damage on diverse middle Palaeocene plants,Menat, France

Insect herbivores are considered vulnerable to extinctions of their plant hosts. Previous studies of insect-damaged fossil leaves in the US Western Interior showed major plant and insect herbivore extinction at the Cretaceous–Palaeogene (K–T) boundary. Further, the regional plant–insect system remained depressed or ecologically unbalanced throughout the Palaeocene. Whereas Cretaceous floras had high plant and insect-feeding diversity, all Palaeocene assemblages to date had low richness of plants, insect feeding or both. Here, we use leaf fossils from the middle Palaeocene Menat site, France, which has the oldest well-preserved leaf assemblage from the Palaeocene of Europe, to test the generality of the observed Palaeocene US pattern. Surprisingly, Menat combines high floral diversity with high insect activity, making it the first observation of a ‘healthy’ Palaeocene plant–insect system. Furthermore, rich and abundant leaf mines across plant species indicate well-developed host specialization. The diversity and complexity of plant–insect interactions at Menat suggest that the net effects of the K–T extinction were less at this greater distance from the Chicxulub, Mexico, impact site. Along with the available data from other regions, our results show that the end-Cretaceous event did not cause a uniform, long-lasting depression of global terrestrial ecosystems. Rather, it gave rise to varying regional patterns of ecological collapse and recovery that appear to have been strongly influenced by distance from the Chicxulub structure.     

Evidence against a role of P-glycoprotein in the clearance of the Alzheimer’s disease Aβ1–42 peptides

It has been proposed that the amyloid-β peptides (Aβ) cause the neuronal degeneration in the Alzheimer’s disease brain. An imbalance between peptide production at the neuronal level and their elimination across the blood–brain–barrier (BBB) results in peptide accumulation inside the brain. The identification and functional characterization of the transport systems in the BBB with the capacity to transport Aβ is crucial for the understanding of Aβ peptide traffic from the brain to the blood. In this context, it has been suggested that the P-glycoprotein (P-gp), expressed in endothelial cells of the BBB, plays a role in the elimination of Aβ. However, there is little, if any, experimental evidence to support this; therefore, the aim of this investigation was to determine whether P-gp is capable of transporting Aβ peptides. Our results show that ATPase activity measured in plasma membrane vesicles of K562 cells overexpressing P-gp is not increased by the presence of Aβ₄₂, suggesting that Aβ₄₂ is not a P-gp substrate. Similarly, P-gp of pirarubicin was unaffected by Aβ₄₂. Moreover, the overexpression of P-gp does not protect cells against Aβ₄₂ toxicity. Taken together, our results support the conclusion that Aβ₄₂ is not transported by P-gp.     

The bounce of the body in hopping,running and trotting: different machines with the same motor

The bouncing mechanism of human running is characterized by a shorter duration of the brake after ‘landing’ compared with a longer duration of the push before ‘takeoff’. This landing–takeoff asymmetry has been thought to be a consequence of the force–velocity relation of the muscle, resulting in a greater force exerted during stretching after landing and a lower force developed during shortening before takeoff. However, the asymmetric lever system of the human foot during stance may also be the cause. Here, we measure the landing–takeoff asymmetry in bouncing steps of running, hopping and trotting animals using diverse lever systems. We find that the duration of the push exceeds that of the brake in all the animals, indicating that the different lever systems comply with the basic property of muscle to resist stretching with a force greater than that developed during shortening. In addition, results show both the landing–takeoff asymmetry and the mass-specific vertical stiffness to be greater in small animals than in large animals. We suggest that the landing–takeoff asymmetry is an index of a lack of elasticity, which increases with increasing the role of muscle relative to that of tendon within muscle–tendon units.     

Integrating high‐speed videos in capture‐mark‐recapture studies of insects

Capture–mark–recapture (CMR) studies have been used extensively in ecology and evolution. While it is feasible to apply CMR in some animals, it is considerably more challenging in small fast‐moving species such as insects. In these groups, low recapture rates can bias estimates of demographic parameters, thereby handicapping effective analysis and management of wild populations. Here, we use high‐speed videos (HSV) to capture two large dragonfly species, Anax junius and Rhionaeschna multicolor, that rarely land and, thus, are particularly challenging for CMR studies. We test whether HSV, compared to conventional “eye” observations, increases the “resighting” rates and, consequently, improves estimates of both survival rates and the effects of demographic covariates on survival. We show that the use of HSV increases the number of resights by 64% in A. junius and 48% in R. multicolor. HSV improved our estimates of resighting and survival probability which were either under‐ or overestimated with the conventional observations. Including HSV improved credible intervals for resighting rate and survival probability by 190% and 130% in A. junius and R. multicolor, respectively. Hence, it has the potential to open the door to a wide range of research possibilities on species that are traditionally difficult to monitor with distance sampling, including within insects and birds.     

Does the intensive grazing and aridity change the relations between the dominant shrub Artemisia kopetdaghensis and plants under its canopies?

The interspecific plant interactions along grazing and aridity stress gradients represent a major research issue in plant ecology. However, the combined effects of these two factors on plant–plant interactions have been poorly studied in the northeast of Iran. To fill this knowledge gap, 144 plots were established in 12 study sites with different grazing intensities (high vs. low) and climatic characteristics (arid vs. semiarid) in northeastern Iran. A dominant shrub, Artemisia kopetdaghensis, was selected as the model species. Further, we studied changes in plant life strategies along the combined grazing and aridity stress gradients. In this study, we used relative interaction indices calculated for species richness, Shannon diversity, and species cover to determine plant–plant interactions using linear mixed‐effect models (LMM). The indicator species analysis was used to identify the indicator species for the undercanopy of shrub and for the adjacent open areas. The combined effects of grazing and aridity affected the plant–plant interactions and plant life strategies (CSR) of indicator species. A. kopetdaghensis showed the highest facilitation effect under high stress conditions (high grazing, high aridity), which turned into competition under the low stress conditions (low grazing, low aridity). In the arid region, the canopy of the shrub protected ruderals, annual forbs, and grasses in both high and low grazing intensities. In the semiarid region and high grazing intensity (low aridity/high grazing), the shrubs protected mostly perennial forbs with C‐strategy. Our findings highlight the importance of context‐dependent shrub management to restore the vegetation damaged by the intensive grazing.     

Parallel evolution of trehalose production machinery in anhydrobiotic animals via recurrent gene loss and horizontal transfer

Trehalose is a versatile non-reducing sugar. In some animal groups possessing its intrinsic production machinery, it is used as a potent protectant against environmental stresses, as well as blood sugar. However, the trehalose biosynthesis genes remain unidentified in the large majority of metazoan phyla, including vertebrates. To uncover the evolutionary history of trehalose production machinery in metazoans, we scrutinized the available genome resources and identified bifunctional trehalose-6-phosphate synthase-trehalose-6-phosphate phosphatase (TPS–TPP) genes in various taxa. The scan included our newly sequenced genome assembly of a desiccation-tolerant tardigrade Paramacrobiotus sp. TYO, revealing that this species retains TPS–TPP genes activated upon desiccation. Phylogenetic analyses identified a monophyletic group of the many of the metazoan TPS–TPP genes, namely ‘pan-metazoan’ genes, that were acquired in the early ancestors of metazoans. Furthermore, coordination of our results with the previous horizontal gene transfer studies illuminated that the two tardigrade lineages, nematodes and bdelloid rotifers, all of which include desiccation-tolerant species, independently acquired the TPS–TPP homologues via horizontal transfer accompanied with loss of the ‘pan-metazoan’ genes. Our results indicate that the parallel evolution of trehalose synthesis via recurrent loss and horizontal transfer of the biosynthesis genes resulted in the acquisition and/or augmentation of anhydrobiotic lives in animals.     

Mitochondrial Tim9 protects Tim10 from degradation by the protease Yme1

Translocase of IM (inner membrane; Tim)9 and Tim10 are essential homologue proteins of the mitochondrial intermembrane space (IMS) and form a stable hexameric Tim9–Tim10 complex there. Redox-switch of the four conserved cysteine residues plays a key role during the biogenesis of these proteins and, in turn, the Tim proteins play a vital chaperone-like role during import of mitochondrial membrane proteins. However, the functional mechanism of the small Tim chaperones is far from solved and it is unclear whether the individual proteins play specific roles or the complex functions as a single unit. In the present study, we examined the requirement and role for the individual disulfide bonds of Tim9 on cell viability, complex formation and stability using yeast genetic, biochemical and biophysical methods. Loss of the Tim9 inner disulfide bond led to a temperature-sensitive phenotype and degradation of both Tim9 and Tim10. The growth phenotype could be suppressed by deletion of the mitochondrial i-AAA (ATPases associated with diverse cellular activities) protease Yme1, and this correlates strongly with stabilization of the Tim10 protein regardless of Tim9 levels. Formation of both disulfide bonds is not essential for Tim9 function, but it can facilitate the formation and improve the stability of the hexameric Tim9–Tim10 complex. Furthermore, our results suggest that the primary function of Tim9 is to protect Tim10 from degradation by Yme1 via assembly into the Tim9–Tim10 complex. We propose that Tim10, rather than the hexameric Tim9–Tim10 complex, is the functional form of these proteins.     

Neuropathy in COVID-19 associated with dysbiosis-related inflammation

Although COVID-19 affects mainly lungs with a hyperactive and imbalanced immune response, gastrointestinal and neurological symptoms such as diarrhea and neuropathic pains have been described as well in patients with COVID-19. Studies indicate that gut–lung axis maintains host homeostasis and disease development with the association of immune system, and gut microbiota is involved in the COVID-19 severity in patients with extrapulmonary conditions. Gut microbiota dysbiosis impairs the gut permeability resulting in translocation of gut microbes and their metabolites into the circulatory system and induce systemic inflammation which, in turn, can affect distal organs such as the brain. Moreover, gut microbiota maintains the availability of tryptophan for kynurenine pathway, which is important for both central nervous and gastrointestinal system in regulating inflammation. SARS-CoV-2 infection disturbs the gut microbiota and leads to immune dysfunction with generalized inflammation. It has been known that cytokines and microbial products crossing the blood-brain barrier induce the neuroinflammation, which contributes to the pathophysiology of neurodegenerative diseases including neuropathies. Therefore, we believe that both gut–lung and gut–brain axes are involved in COVID-19 severity and extrapulmonary complications. Furthermore, gut microbial dysbiosis could be the reason of the neurologic complications seen in severe COVID-19 patients with the association of dysbiosis-related neuroinflammation. This review will provide valuable insights into the role of gut microbiota dysbiosis and dysbiosis-related inflammation on the neuropathy in COVID-19 patients and the disease severity.     

Modularity and specialization in bat–fly interaction networks are remarkably consistent across patches within urbanized landscapes and spatial scales

Patterns of specialization and the structure of interactions between bats and ectoparasitic flies have been studied mostly on non-urban environments and at local scales. Thus, how anthropogenic disturbances influence species interactions and network structure in this system remain poorly understood. Here, we investigated patterns of interaction between Phyllostomidae bats and ectoparasitic Streblidae flies, and variations in network specialization and structure across Cerrado patches within urbanized landscapes in Brazil and between local and regional scales. We found high similarity in the richness and composition of bat and fly species across communities, associated with low turnover of interactions between networks. The high specialization of bat–streblid interactions resulted in little connected and modular networks, with the emergence of modules containing subsets of species that interact exclusively or primarily with each other. Such similarities in species and interaction composition and network structure across communities and scales suggest that bat–fly interactions within Cerrado patches are little affected by the degree of human modification in the surrounding matrix. This remarkable consistency is likely promoted by specific behaviors, the tolerance of Phyllostomidae bats to surrounding urbanized landscapes as well as by the specificity of the streblid–bat interactions shaped over evolutionary time.     

Can size distributions of European lake fish communities be predicted by trophic positions of their fish species?

An organism''s body size plays an important role in ecological interactions such as predator–prey relationships. As predators are typically larger than their prey, this often leads to a strong positive relationship between body size and trophic position in aquatic ecosystems. The distribution of body sizes in a community can thus be an indicator of the strengths of predator–prey interactions. The aim of this study was to gain more insight into the relationship between fish body size distribution and trophic position in a wide range of European lakes. We used quantile regression to examine the relationship between fish species'' trophic position and their log‐transformed maximum body mass for 48 fish species found in 235 European lakes. Subsequently, we examined whether the slopes of the continuous community size distributions, estimated by maximum likelihood, were predicted by trophic position, predator–prey mass ratio (PPMR), or abundance (number per unit effort) of fish communities in these lakes. We found a positive linear relationship between species'' maximum body mass and average trophic position in fishes only for the 75% quantile, contrasting our expectation that species'' trophic position systematically increases with maximum body mass for fish species in European lakes. Consequently, the size spectrum slope was not related to the average community trophic position, but there were negative effects of community PPMR and total fish abundance on the size spectrum slope. We conclude that predator–prey interactions likely do not contribute strongly to shaping community size distributions in these lakes.     

The N-terminal domain of the Schaaf–Yang syndrome protein MAGEL2 likely has a role in RNA metabolism

MAGEL2 encodes the L2 member of the melanoma-associated antigen gene (MAGE) protein family, truncating mutations of which can cause Schaaf-Yang syndrome, an autism spectrum disorder. MAGEL2 is also inactivated in Prader–Willi syndrome, which overlaps clinically and mechanistically with Schaaf–Yang syndrome. Studies to date have only investigated the C-terminal portion of the MAGEL2 protein, containing the MAGE homology domain that interacts with RING-E3 ubiquitin ligases and deubiquitinases to form protein complexes that modify protein ubiquitination. In contrast, the N-terminal portion of the MAGEL2 protein has never been studied. Here, we find that MAGEL2 has a low-complexity intrinsically disordered N-terminus rich in Pro-X_n-Gly motifs that is predicted to mediate liquid–liquid phase separation to form biomolecular condensates. We used proximity-dependent biotin identification (BioID) and liquid chromatography–tandem mass spectrometry to identify MAGEL2-proximal proteins, then clustered these proteins into functional networks. We determined that coding mutations analogous to disruptive mutations in other MAGE proteins alter these networks in biologically relevant ways. Proteins identified as proximal to the N-terminal portion of MAGEL2 are primarily involved in mRNA metabolic processes and include three mRNA N 6-methyladenosine (m⁶A)-binding YTHDF proteins and two RNA interference-mediating TNRC6 proteins. We found that YTHDF2 coimmunoprecipitates with MAGEL2, and coexpression of MAGEL2 reduces the nuclear accumulation of YTHDF2 after heat shock. We suggest that the N-terminal region of MAGEL2 may have a role in RNA metabolism and in particular the regulation of mRNAs modified by m⁶A methylation. These results provide mechanistic insight into pathogenic MAGEL2 mutations associated with Schaaf–Yang syndrome and related disorders.     

Differences in brain morphology of brown trout across stream,lake, and hatchery environments

It has been suggested that a trade‐off between cognitive capacity and developmental costs may drive brain size and morphology across fish species, but this pattern is less well explored at the intraspecific level. Physical habitat complexity has been proposed as a key selection pressure on cognitive capacity that shapes brain morphology of fishes. In this study, we compared brain morphology of brown trout, Salmo trutta, from stream, lake, and hatchery environments, which generally differ in physical complexity ranging from low habitat complexity in the hatchery to high habitat complexity in streams and intermediate complexity in lakes. We found that brain size, and the size of optic tectum and telencephalon differed across the three habitats, both being largest in lake fish with a tendency to be smaller in the stream compared to hatchery fish. Therefore, our findings do not support the hypothesis that in brown trout the volume of brain and its regions important for navigation and decision‐making increases in physically complex habitats. We suggest that the observed differences in brain size might be associated with diet quality and habitat‐specific behavioral adaptations rather than physical habitat complexity.