LYVE-1-expressing macrophages modulate the hyaluronan-containing extracellular matrix in the mammary stroma and contribute to mammary tumor growth.

Macrophages represent a heterogeneous myeloid population with diverse functions in normal tissues and tumors. While macrophages expressing the cell surface marker lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) have been identified in stromal regions of the normal mammary gland and in the peri-tumoral stroma, their functions within these regions are not well-understood. Using a genetic mouse model of LYVE-1+ macrophage depletion, we demonstrate that loss of LYVE-1+ macrophages is associated with altered extracellular matrix remodeling in the normal mammary gland and reduced mammary tumor growth in vivo. In further studies focused on investigating the functions of LYVE-1+ macrophages in the tumor microenvironment, we demonstrate that LYVE-1 expression correlates with an increased ability of macrophages to bind, internalize, and degrade hyaluronan. Consistent with this, we show that depletion of LYVE-1+ macrophages correlates with increased hyaluronan accumulation in both the normal mammary gland and in mammary tumors. Analysis of single cell RNA sequencing of macrophages isolated from these tumors reveals that depletion of LYVE-1+ macrophages in tumors drives a shift in the majority of the remaining macrophages towards a pro-inflammatory phenotype, as well as an increase in CD8+ T cell infiltration. Together, these findings indicate that LYVE-1+ macrophages represent a tumor-promoting anti-inflammatory subset of macrophages that contributes to hyaluronan remodeling in the tumor microenvironment.

Bird tolerance to humans in open tropical ecosystems.

Animal tolerance towards humans can be a key factor facilitating wildlife-human coexistence, yet traits predicting its direction and magnitude across tropical animals are poorly known. Using 10,249 observations for 842 bird species inhabiting open tropical ecosystems in Africa, South America, and Australia, we find that avian tolerance towards humans was lower (i.e., escape distance was longer) in rural rather than urban populations and in populations exposed to lower human disturbance (measured as human footprint index). In addition, larger species and species with larger clutches and enhanced flight ability are less tolerant to human approaches and escape distances increase when birds were approached during the wet season compared to the dry season and from longer starting distances. Identification of key factors affecting animal tolerance towards humans across large spatial and taxonomic scales may help us to better understand and predict the patterns of species distributions in the Anthropocene.

Universal Behavior of Highly Confined Heat Flow in Semiconductor Nanosystems: From Nanomeshes to Metalattices.

Nanostructuring on length scales corresponding to phonon mean free paths provides control over heat flow in semiconductors and makes it possible to engineer their thermal properties. However, the influence of boundaries limits the validity of bulk models, while first-principles calculations are too computationally expensive to model real devices. Here we use extreme ultraviolet beams to study phonon transport dynamics in a 3D nanostructured silicon metalattice with deep nanoscale feature size and observe dramatically reduced thermal conductivity relative to bulk. To explain this behavior, we develop a predictive theory wherein thermal conduction separates into a geometric permeability component and an intrinsic viscous contribution, arising from a new and universal effect of nanoscale confinement on phonon flow. Using experiments and atomistic simulations, we show that our theory applies to a general set of highly confined silicon nanosystems, from metalattices, nanomeshes, porous nanowires, to nanowire networks, of great interest for next-generation energy-efficient devices.

Structural and Elastic Properties of Empty-Pore Metalattices Extracted via Nondestructive Coherent Extreme UV Scatterometry and Electron Tomography.

Semiconductor metalattices consisting of a linked network of three-dimensional nanostructures with periodicities on a length scale <100 nm can enable tailored functional properties due to their complex nanostructuring. For example, by controlling both the porosity and pore size, thermal transport in these phononic metalattices can be tuned, making them promising candidates for efficient thermoelectrics or thermal rectifiers. Thus, the ability to characterize the porosity, and other physical properties, of metalattices is critical but challenging, due to their nanoscale structure and thickness. To date, only metalattices with high porosities, close to the close-packing fraction of hard spheres, have been studied experimentally. Here, we characterize the porosity, thickness, and elastic properties of a low-porosity, empty-pore silicon metalattice film (∼500 nm thickness) with periodic spherical pores (∼tens of nanometers), for the first time. We use laser-driven nanoscale surface acoustic waves probed by extreme ultraviolet scatterometry to nondestructively measure the acoustic dispersion in these thin silicon metalattice layers. By comparing the data to finite element models of the metalattice sample, we can extract Young's modulus and porosity. Moreover, by controlling the acoustic wave penetration depth, we can also determine the metalattice layer thickness and verify the substrate properties. Additionally, we utilize electron tomography images of the metalattice to verify the geometry and validate the porosity extracted from scatterometry. These advanced characterization techniques are critical for informed and iterative fabrication of energy-efficient devices based on nanostructured metamaterials.

Cone photoreceptors in human stem cell-derived retinal organoids demonstrate intrinsic light responses that mimic those of primate fovea.

High-definition vision in humans and nonhuman primates is initiated by cone photoreceptors located within a specialized region of the retina called the fovea. Foveal cone death is the ultimate cause of central blindness in numerous retinal dystrophies, including macular degenerative diseases. 3D retinal organoids (ROs) derived from human pluripotent stem cells (hPSCs) hold tremendous promise to model and treat such diseases. To achieve this goal, RO cones should elicit robust and intrinsic light-evoked electrical responses (i.e., phototransduction) akin to adult foveal cones, which has not yet been demonstrated. Here, we show strong, graded, repetitive, and wavelength-specific light-evoked responses from RO cones. The photoresponses and membrane physiology of a significant fraction of these lab-generated cones are comparable with those of intact ex vivo primate fovea. These results greatly increase confidence in ROs as potential sources of functional human cones for cell replacement therapies, drug testing, and in vitro models of retinal dystrophies.

Disinfection of Maternal Environments Is Associated with Piglet Microbiome Composition from Birth to Weaning.

Maternal factors predetermine offspring development and health, including the establishment of offsprings' first microbiomes. Research in swine has shown that early microbial exposures impact microbiome colonization in piglets, but this phenomenon has never been tested in the context of delivery room disinfection. Thus, we exposed gestating sows to two delivery environments (n = 3/environment): stalls cleaned with a broad-spectrum disinfectant (disinfected environment [D]) or stalls cleaned only with hot-water power washing (nondisinfected environment [Nde]), 3 days prior to farrowing. Microbiomes of sows and farrowed piglets (n = 27/environment) were profiled at 4 different time points from birth to weaning via 16S rRNA sequencing. The results show that although vaginal, milk, skin, and gut microbiomes in mothers were minimally affected, sanitation of farrowing stalls impacted piglet microbiome colonization. These effects were mainly characterized by lower bacterial diversity in the gut and nasal cavity, specifically in D piglets at birth, and by distinct taxonomic compositions from birth to weaning depending on the farrowing environment. For instance, environmental bacteria greatly influenced microbiome colonization in Nde piglets, which also harbored significantly higher abundances of gut Lactobacillus and nasal Enhydrobacter at several time points through weaning. Different sanitation strategies at birth also resulted in distinct microbiome assembly patterns, with lower microbial exposures in D piglets being associated with limited interactions between bacterial taxa. However, increasing microbial exposures at birth through the lack of disinfection were also associated with lower piglet weight, highlighting the importance of understanding the trade-offs among optimal microbiome development, health, and growth performance in swine production systems. IMPORTANCE We show that levels of disinfection in farrowing facilities can impact early microbial exposures and colonization by pioneer microbes in piglets. Although previous research has shown a similar effect by raising pigs outdoors or by exposing them to soil, these practices are unattainable in most swine production systems in the United States due to biosecurity practices. Thus, our results underscore the importance of evaluating different disinfection practices in swine production to safely reduce pathogenic risks without limiting early microbial exposures. Allowing early exposure to both beneficial and pathogenic microbes may positively impact immune responses, reduce the stressors of weaning, and potentially reduce the need for dietary antimicrobials. However, the benefits of modified early microbial exposures need to be accomplished along with acceptable growth performance. Thus, our results also provide clues for understanding how disinfection practices in farrowing rooms may impact early microbiome development and assembly.

A new fanged frog in the Limnonectes kuhlii complex (Anura: Dicroglossidae) from northeastern Cambodia.

The Limnonectes kuhlii complex is a group of morphologically similar species of fanged frogs distributed across much of mainland and insular Southeast Asia. Many new species in this complex have been described in recent years, primarily on the basis of mitochondrial DNA divergence corroborated by differences in linear measurements and qualitative characters. Males in this species complex develop enlarged heads at sexual maturity, but the degree of head enlargement varies among mature males, even within the same population. We evaluated the utility of body length (snout-vent length minus head length) in descriptive statistics and in size-adjusting measurements for traditional morphometric analysis, as well as a landmark-based geometric morphometric analysis of male head shape, in Indochinese species of the L. kuhlii complex. The analyses supported quantitative and qualitative morphological distinction of a divergent mitochondrial lineage of the L. kuhlii complex in northeastern Cambodia, and the lineage is described as a new species. Limnonectes fastigatus sp. nov. differs from its closest relatives and from geographically proximate members of the complex by having the combination of elongated, slender odontoids; nuptial pads on the first finger; immaculate belly; significantly different body length-adjusted measurements in both sexes; and a significantly different male head shape. The new species is the only member of the L. kuhlii complex known from Cambodia.

Cauterization as a Simple Method for Regeneration Studies in the Zebrafish Heart.

In the last two decades, the zebrafish has emerged as an important model species for heart regeneration studies. Various approaches to model loss of cardiac myocytes and myocardial infarction in the zebrafish have been devised, and have included resection, genetic ablation, and cryoinjury. However, to date, the response of the zebrafish ventricle to cautery injury has not been reported. Here, we describe a simple and reproducible method using cautery injury via a modified nichrome inoculating needle as a probe to model myocardial infarction in the zebrafish ventricle. Using light and electron microscopy, we show that cardiac cautery injury is attended by significant inflammatory cell infiltration, accumulation of collagen in the injured area, and the reconstitution of the ventricular myocardium. Additionally, we document the ablation of cardiac nerve fibers, and report that the re-innervation of the injured zebrafish ventricle is protracted, compared to other repair processes that accompany the regeneration of the cauterized ventricle. Taken together, our study demonstrates that cautery injury is a simple and effective means for generating necrotic tissue and eliciting a remodeling and regenerative response in the zebrafish heart. This approach may serve as an important tool in the methods toolbox for regeneration studies in the zebrafish.

Risk perception of vervet monkeys Chlorocebus pygerythrus to humans in urban and rural environments.

Like other animals, primates respond to predation using behavioural adaptations. Hence, they should optimise their escape strategy under the risk of predation, and flee at a distance, referred to as flight initiation distance (FID), when the fitness-related benefits of staying are balanced against the costs of escape. However, there is an absence of FID studies in primates. In this study, we used vervet monkeys Chlorocebus pygerythrus, a medium-sized African cercopithecoid, as a model species to investigate the influence of environment type (urban and rural), group size (defined as the number of visible neighbours), sex and age on FID when approached by a human. We found significantly shorter FID among urban than rural monkeys; urban individuals delayed their escape compared to rural individuals. We found no relationship between FID and sex and age class, but FID was positively correlated with group size in both settings; urban monkeys live in smaller groups than monkeys in rural areas. As FID and group size are important predictors of predation risk perception in primates, results suggest that, despite probable effects of habituation, vervet monkeys in Uganda adjust their antipredator behaviour when coping with novel environments within human settlements. Our findings are consistent with some previous studies of risk perception in animals, and indicate that FID could be used as an alternative measure for predation risk in primates.

The common cuckoo is an effective indicator of high bird species richness in Asia and Europe.

Common cuckoo Cuculus canorus is a charismatic bird species with a dominant presence in human culture: from folklore legends to nowadays there is evidence of cuckoos being a prime candidate as a surrogate of bird diversity. Recent studies demonstrated that the cuckoo can predict hotspots of taxonomic diversity and functional diversity of bird communities in European countries. In this study, we demonstrated that the cuckoo is an excellent bioindicator at multi-spatial scale, extending cuckoo surrogacy from Europe to Asia. Even using three different survey methods (transect, square, point counts), comparing the new findings with results of our research in Europe, sites where the cuckoo is present were characterized by greater species richness, while the cuckoo was absent from sites with low species richness. The goodness of fit of models based on point counts ranged between 71 and 92%. Furthermore, the cuckoo population trend mirrors the average population trend and climate suitability of overall bird communities in Europe. The common cuckoo is therefore a suitable intercontinental bioindicator of hotspots of bird richness, even under climate change scenarios or in areas where the species co-occurs with other cuckoo species, opening a new avenue for standardized citizen science on bird biodiversity surveys worldwide.

A systematic review of animal predation creating pierced shells: implications for the archaeological record of the Old World.

BACKGROUND: The shells of molluscs survive well in many sedimentary contexts and yield information about the diet of prehistoric humans. They also yield evidence of symbolic behaviours through their use as beads for body adornments. Researchers often analyse the location of perforations in shells to make judgements about their use as symbolic objects (e.g., beads), the assumption being that holes attributable to deliberate human behaviour are more likely to exhibit low variability in their anatomical locations, while holes attributable to natural processes yield more random perforations. However, there are non-anthropogenic factors that can cause perforations in shells and these may not be random. The aim of the study is compare the variation in holes in shells from archaeological sites from the Old World with the variation of holes in shells pierced by mollusc predators. METHODS: Three hundred and sixteen scientific papers were retrieved from online databases by using keywords, (e.g., 'shell beads'; 'pierced shells'; 'drilling predators'); 79 of these publications enabled us to conduct a systematic review to qualitatively assess the location of the holes in the shells described in the published articles. In turn, 54 publications were used to assess the location of the holes in the shells made by non-human predators. RESULTS: Almost all archaeological sites described shells with holes in a variety of anatomical locations. High variation of hole-placement was found within the same species from the same site, as well as among sites. These results contrast with research on predatory molluscs, which tend to be more specific in where they attacked their prey. Gastropod and bivalve predators choose similar hole locations to humans. DISCUSSION: Based on figures in the analysed articles, variation in hole-location on pierced shells from archaeological sites was similar to variation in the placement of holes created by non-human animals. Importantly, we found that some predators choose similar hole locations to humans. We discuss these findings and identify factors researchers might want to consider when interpreting shells recovered from archaeological contexts.

No Sexual Dimorphism Detected in Digit Ratios of the Fire Salamander (Salamandra salamandra).

It has been proposed that digit ratio may be used as a biomarker of early developmental effects. Specifically, the second-to-fourth digit ratio (2D:4D) has been linked to the effects of sex hormones and their receptor genes, but other digit ratios have also been investigated. Across taxa, patterns of sexual dimorphism in digit ratios are ambiguous and a scarcity of studies in basal tetrapods makes it difficult to understand how ratios have evolved. Here, we focus on examining sex differences in digit ratios (2D:3D, 2D:4D, and 3D:4D) in a common amphibian, the fire salamander (Salamandra salamandra). We used graphic software to measure soft tissue digit length and digit bone length from X-rays. We found a nonsignificant tendency in males to have a lower 2D:3D than females; however, no sexual differences were detected in the other ratios. We discuss our results in the context of other studies of digit ratios, and how sex determination systems, as well as other factors, might impact patterns of sexual dimorphism, particularly in reptiles and in amphibians. Our findings suggest that caution is needed when using digit ratios as a potential indicator of prenatal hormonal effects in amphibians and highlight the need for more comparative studies to elucidate the evolutionary and genetic mechanisms implicated in sexually dimorphic patterns across taxonomic groups.

Hominin cognitive evolution: identifying patterns and processes in the fossil and archaeological record.

As only limited insight into behaviour is available from the archaeological record, much of our understanding of historical changes in human cognition is restricted to identifying changes in brain size and architecture. Using both absolute and residual brain size estimates, we show that hominin brain evolution was likely to be the result of a mix of processes; punctuated changes at approximately 100 kya, 1 Mya and 1.8 Mya are supplemented by gradual within-lineage changes in Homo erectus and Homo sapiens sensu lato. While brain size increase in Homo in Africa is a gradual process, migration of hominins into Eurasia is associated with step changes at approximately 400 kya and approximately 100 kya. We then demonstrate that periods of rapid change in hominin brain size are not temporally associated with changes in environmental unpredictability or with long-term palaeoclimate trends. Thus, we argue that commonly used global sea level or Indian Ocean dust palaeoclimate records provide little evidence for either the variability selection or aridity hypotheses explaining changes in hominin brain size. Brain size change at approximately 100 kya is coincident with demographic change and the appearance of fully modern language. However, gaps remain in our understanding of the external pressures driving encephalization, which will only be filled by novel applications of the fossil, palaeoclimatic and archaeological records.

Digit ratios predict polygyny in early apes, Ardipithecus, Neanderthals and early modern humans but not in Australopithecus.

Social behaviour of fossil hominoid species is notoriously difficult to predict owing to difficulties in estimating body size dimorphism from fragmentary remains and, in hominins, low canine size dimorphism. Recent studies have shown that the second-to-fourth digit ratio (2D : 4D), a putative biomarker for prenatal androgen effects (PAEs), covaries with intra-sexual competition and social systems across haplorrhines; non-pair-bonded polygynous taxa have significantly lower 2D : 4D ratios (high PAE) than pair-bonded monogamous species. Here, we use proximal phalanx ratios of extant and fossil specimens to reconstruct the social systems of extinct hominoids. Pierolapithecus catalaunicus, Hispanopithecus laietanus and Ardipithecus ramidus have ratios consistent with polygynous extant species, whereas the ratio of Australopithecus afarensis is consistent with monogamous extant species. The early anatomically modern human Qafzeh 9 and Neanderthals have lower digit ratios than most contemporary human populations, indicating increased androgenization and possibly higher incidence of polygyny. Although speculative owing to small sample sizes, these results suggest that digit ratios represent a supplementary approach for elucidating the social systems of fossil hominins.

Heritability of digit ratio (2D:4D) in rhesus macaques (Macaca mulatta).

The second-to-fourth digit ratio (2D:4D) is a putative biomarker for prenatal androgen effects, which has been widely employed to study androgenic-programming effects on shaping sex-linked traits and behaviours in humans. This approach is now increasingly applied to non-human species. Heritability studies of 2D:4D in both humans and zebra finches indicate substantial genetic contributions to the expression of this trait. This study examines the heritability of 2D:4D in rhesus macaques, based on the resemblance of mother-infant dyads, to see how these compare with human values. Results suggest that familial resemblance in 2D:4D is also strong in rhesus monkeys. Heritability estimates were within the range of estimates from human studies. These preliminary results suggest that the strength of heritability of 2D:4D may generalize across taxa.

Finger length ratios (2D:4D) in anthropoids implicate reduced prenatal androgens in social bonding.

The second-to-fourth digit ratio (2D:4D) has been proposed as a biomarker reflecting prenatal androgen effects (PAE), such that individuals with lower ratios have experienced higher PAE than those with higher ratios. 2D:4D has been correlated with a number of sex-linked traits in humans such as aggression, promiscuity, and competitiveness. In addition, polygynous societies reportedly have lower 2D:4D (higher PAE) than more monogamous populations. This evidence suggests that PAE may be implicated in the development of sexually selected behaviors in humans. To place 2D:4D research into a broader context, we test the relationship between digit ratios and behavior across nonhuman anthropoids; polygynous species, with higher levels of intrasexual competition, should have more pronounced markers of PAE (lower 2D:4D) than pair-bonded species. Our results accord with those found in humans: 2D:4D is lower in polygynous species and higher (lower PAE) in pair-bonded species. Old World monkeys have low, and relatively invariant 2D:4D (high PAE), which is coupled with high levels of intrasexual competition. This contrasts with higher and more variable ratios in both great apes and New World monkeys. In addition, both male and female ratios decrease with increasing levels of intrasexual competition. Human ratios are intermediate between pair-bonded and more promiscuous hominoids. We propose that PAE may be involved in promoting species characteristic social behavior in anthropoids.

2D:4D and sexually dimorphic facial characteristics.

The second-to-fourth-digit ratio (2D:4D) may be related to prenatal testosterone and estrogen levels and pubertal face growth. Several studies have recently provided evidence that 2D:4D is associated with other-rated facial masculinity and dominance, but not with facialmetric measures of masculinity. We found that localized face shape differences, shown here to be sexually dimorphic and related to ratings of dominance, were associated with direct and indirect measurements of 2D:4D. In this study we examined various localized features of the face, showing nose width, jaw angle, and lip height to be sexually dimorphic. We then had faces rated for dominance and saw that the most dimorphic characteristics were those most associated with rated dominance, with typically masculine characteristics tending to be associated with high ratings of dominance. Finally, 2D:4D measurements were made using three different techniques. High (feminine) values of 2D:4D were associated with feminine facial characteristics in women, but not in men. It was concluded that certain aspects of facial development are governed by factors that are established prenatally. These aspects may be associated with perceptions of the self by others that are important in the social environment, particularly in terms of intra-sexual competition and mate acquisition.