bluuebunny/crossref_metadata_2025 huggingface dataset:
Active vitamin D is cardioprotective in experimental uraemia but not in children with CKD Stages 3–5
Authors: Schön Anne , Leifheit-Nestler Maren , Deppe Jennifer , Fischer Dagmar-Christiane , Bayazit Aysun K , Obrycki Lukasz , Canpolat Nur , Bulut Ipek Kaplan , Azukaitis Karolis , Yilmaz Alev , Mir Sevgi , Yalcinkaya Fatos , Soylemezoglu Oguz , Melk Anette , Stangl Gabriele I , Behnisch Rouven , Shroff Rukshana , Bacchetta Justine , Querfeld Uwe , Schaefer Franz , Haffner Dieter ,   for the 4C and Study Consortium and the ESPN CKD-MBD Working Group
Published: August 2020

Background

Uraemic cardiac remodelling is associated with vitamin D and Klotho deficiency, elevated fibroblast growth factor 23 (FGF23) and activation of the renin–angiotensin system (RAS). The cardioprotective properties of active vitamin D analogues in this setting are unclear.

Methods

In rats with 5/6 nephrectomy (5/6Nx) treated with calcitriol, the cardiac phenotype and local RAS activation were investigated compared with controls. A nested case–control study was performed within the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, including children with chronic kidney disease (CKD) Stages 3–5 [estimated glomerular filtration rate (eGFR) 25 mL/min/1.73 m2] treated with and without active vitamin D. Echocardiograms, plasma FGF23 and soluble Klotho (sKlotho) were assessed at baseline and after 9 months.

Results

In rats with 5/6Nx, left ventricular (LV) hypertrophy, LV fibrosis and upregulated cardiac RAS were dose-dependently attenuated by calcitriol. Calcitriol further stimulated FGF23 synthesis in bone but not in the heart, and normalized suppressed renal Klotho expression. In the 4C study cohort, treatment over a mean period of 9 months with active vitamin D was associated with increased FGF23 and phosphate and decreased sKlotho and eGFR compared with vitamin D naïve controls, whereas LV mass index did not differ between groups.

Conclusions

Active vitamin D ameliorates cardiac remodelling and normalizes renal Klotho expression in 5/6Nx rats but does not improve the cardiac phenotype in children with CKD Stages 3–5. This discrepancy may be due to further enhancement of circulating FGF23 and faster progression of CKD associated with reduced sKlotho and higher serum phosphate in vitamin D-treated patients.
Medical management of brain metastases
Authors: Lauko Adam , Rauf Yasmeen , Ahluwalia Manmeet S
Published: August 2020

Absrtract

The development of brain metastases occurs in 10–20% of all patients with cancer. Brain metastases portend poor survival and contribute to increased cancer mortality and morbidity. Despite multimodal treatment options, which include surgery, radiotherapy, and chemotherapy, 5-year survival remains low. Besides, our current treatment modalities can have significant neurological comorbidities, which result in neurocognitive decline and a decrease in a patient’s quality of life. However, innovations in technology, improved understanding of tumor biology, and new therapeutic options have led to improved patient care. Novel approaches in radiotherapy are minimizing the neurocognitive decline while providing the same therapeutic benefit. In addition, advances in targeted therapies and immune checkpoint inhibitors are redefining the management of lung and melanoma brain metastases. Similar approaches to brain metastases from other primary tumors promise to lead to new and effective therapies. We are beginning to understand the appropriate combination of these novel approaches with our traditional treatment options. As advances in basic and translational science and innovative technologies enter clinical practice, the prognosis of patients with brain metastases will continue to improve.
Microbiome-mediated plasticity directs host evolution along several distinct time scales
Authors: Kolodny Oren , Schulenburg Hinrich
Published: August 2020

Host-associated microbiomes influence their host's fitness in myriad ways and can be viewed as a source of phenotypic plasticity. This plasticity may allow the host to accommodate novel environmental challenges and thus influence the host's evolutionary adaptation. As with other modalities of phenotypic plasticity in phenomena such as the Baldwin effect and genetic assimilation, the microbiome-mediated plasticity may influence host genetic adaptation by facilitating and accelerating it, by slowing it down, or even by preventing it. The dynamics involved are likely more complex than those of previously studied phenomena related to phenotypic plasticity, and involve different processes on each time scale, such as acquired recognition of newly associated microbes by the host's immune system on single- and multiple-generation time scales, or selection on transmission dynamics of microbes between hosts, acting on longer time scales. To date, it is unclear if and how any of these processes shape host evolution. This opinion piece article provides a conceptual framework for considering the processes by which microbiome-mediated plasticity directs host evolution and concludes with suggestions for key experimental tests of the presented ideas.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Pathogen resistance may be the principal evolutionary advantage provided by the microbiome
Authors: McLaren Michael R. , Callahan Benjamin J.
Published: August 2020

To survive, plants and animals must continually defend against pathogenic microbes that would invade and disrupt their tissues. Yet they do not attempt to extirpate all microbes. Instead, they tolerate and even encourage the growth of commensal microbes, which compete with pathogens for resources and via direct inhibition. We argue that hosts have evolved to cooperate with commensals in order to enhance the pathogen resistance this competition provides. We briefly describe competition between commensals and pathogens within the host, consider how natural selection might favour hosts that tilt this competition in favour of commensals, and describe examples of extant host traits that may serve this purpose. Finally, we consider ways that this cooperative immunity may have facilitated the adaptive evolution of non-pathogen-related host traits. On the basis of these observations, we argue that pathogen resistance vies with other commensal-provided benefits for being the principal evolutionary advantage provided by the microbiome to host lineages across the tree of life.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Microbiota–host interactions shape ageing dynamics
Authors: Popkes Miriam , Valenzano Dario Riccardo
Published: August 2020

Occupying the interface between host and environment, host-associated microbes play fundamental roles in nutrient absorption, essential metabolite synthesis, development of the immune system, defence against pathogens and pathogenesis. Microbiota composition and function is rather stable during adulthood, while it dramatically changes during early development, frailty and disease. Ageing is associated with progressive decrease of homeostasis, often resulting in disruption of the physiological balance between host and commensal microbes, ultimately leading to dysbiosis and host demise. Generally, high microbial diversity is associated with health and a youthful state, while low individual microbial diversity and larger inter-individual microbial diversity is associated with ageing and disease states. Different species are equipped with species-specific commensal, symbiotic and pathogenic microbial communities. How and whether the specific host–microbiota consortia co-evolved with host physiology to ensure homeostasis and promote individual fitness remains an open question. In this essay, we propose that the evolution of vertebrate-specific immune adaptations may have enabled the establishment of highly diverse, species-specific commensal microbial communities. We discuss how the maintenance of intact immune surveillance mechanisms, which allow discrimination between commensal and pathogenic bacteria, fail during ageing and lead to the onset of known ageing-related diseases. We discuss how host–microbiota interactions are key to maintaining homeostasis despite external perturbations, but also how they affect a range of host-specific ageing-related phenotypes.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Evolution of animal immunity in the light of beneficial symbioses
Authors: Gerardo Nicole M. , Hoang Kim L. , Stoy Kayla S.
Published: August 2020

Immune system processes serve as the backbone of animal defences against pathogens and thus have evolved under strong selection and coevolutionary dynamics. Most microorganisms that animals encounter, however, are not harmful, and many are actually beneficial. Selection should act on hosts to maintain these associations while preventing exploitation of within-host resources. Here, we consider how several key aspects of beneficial symbiotic associations may shape host immune system evolution. When host immunity is used to regulate symbiont populations, there should be selection to evolve and maintain targeted immune responses that recognize symbionts and suppress but not eliminate symbiont populations. Associating with protective symbionts could relax selection on the maintenance of redundant host-derived immune responses. Alternatively, symbionts could facilitate the evolution of host immune responses if symbiont-conferred protection allows for persistence of host populations that can then adapt. The trajectory of immune system evolution will likely differ based on the type of immunity involved, the symbiont transmission mode and the costs and benefits of immune system function. Overall, the expected influence of beneficial symbiosis on immunity evolution depends on how the host immune system interacts with symbionts, with some interactions leading to constraints while others possibly relax selection on immune system maintenance.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Compartmentalization drives the evolution of symbiotic cooperation
Authors: Chomicki Guillaume , Werner Gijsbert D. A. , West Stuart A. , Kiers E. Toby
Published: August 2020

Across the tree of life, hosts have evolved mechanisms to control and mediate interactions with symbiotic partners. We suggest that the evolution of physical structures that allow hosts to spatially separate symbionts, termed compartmentalization, is a common mechanism used by hosts. Such compartmentalization allows hosts to: (i) isolate symbionts and control their reproduction; (ii) reward cooperative symbionts and punish or stop interactions with non-cooperative symbionts; and (iii) reduce direct conflict among different symbionts strains in a single host. Compartmentalization has allowed hosts to increase the benefits that they obtain from symbiotic partners across a diversity of interactions, including legumes and rhizobia, plants and fungi, squid andVibrio, insects and nutrient provisioning bacteria, plants and insects, and the human microbiome. In cases where compartmentalization has not evolved, we ask why not. We argue that when partners interact in a competitive hierarchy, or when hosts engage in partnerships which are less costly, compartmentalization is less likely to evolve. We conclude that compartmentalization is key to understanding the evolution of symbiotic cooperation.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Housing microbial symbionts: evolutionary origins and diversification of symbiotic organs in animals
Authors: Douglas Angela E.
Published: August 2020

In many animal hosts, microbial symbionts are housed within specialized structures known as symbiotic organs, but the evolutionary origins of these structures have rarely been investigated. Here, I adopt an evolutionary developmental (evo-devo) approach, specifically to apply knowledge of the development of symbiotic organs to gain insights into their evolutionary origins and diversification. In particular, host genetic changes associated with evolution of symbiotic organs can be inferred from studies to identify the host genes that orchestrate the development of symbiotic organs, recognizing that microbial products may also play a key role in triggering the developmental programme in some associations. These studies may also reveal whether higher animal taxonomic groups (order, class, phylum, etc.) possess a common genetic regulatory network for symbiosis that is latent in taxa lacking symbiotic organs, and activated at the origination of symbiosis in different host lineages. In this way, apparent instances of convergent evolution of symbiotic organs may be homologous in terms of a common genetic blueprint for symbiosis. Advances in genetic technologies, including reverse genetic tools and genome editing, will facilitate the application of evo-devo approaches to investigate the evolution of symbiotic organs in animals.

This article is part of the theme issue ‘The role of the microbiome in host evolution’.
Mobilization of aKluyvera-likearnBCADTEFoperon, besidesmcrgenes, confers colistin resistance toEscherichia coliisolated from healthy animals
Authors: Gallardo Alejandro , Iglesias María-Rocío , Ugarte-Ruiz María , Hernández Marta , Miguela-Villoldo Pedro , Gutiérrez Gloria , Rodríguez-Lázaro David , Domínguez Lucas , Quesada Alberto
Published: August 2020

The use of colistin as a last resort antimicrobial is compromised by the emergence of resistant enterobacteria with acquired determinants likemcrgenes, mutations that activate the PmrAB two-component system and also by some other(s) still unknown mechanism(s). This work analyzed 74E. coliisolates from healthy swine, turkey or bovine animals, characterizing their colistin resistance determinants. Themcr-1gene, detected in 69 isolates, was the main determinant found among which 45% were carried by highly mobile plasmids, followed by four strains lacking previously known resistance determinants or two withmcr-4(one in addition tomcr-1), whose phenotypes were not transferred by conjugation. Although a fraction of isolates carryingmcr-1ormcr-4genes also presented missense polymorphisms inpmrAorpmrB, constitutive activation of PmrAB was not detected, in contrast to control strains carrying mutations that confer colistin resistance. The expression ofmcrgenes negatively controlsarnBCADTEFexpression, a down-regulation that was also observed in the four isolates lacking known resistance determinants, three of them sharing the same macrorestriction and plasmid profiles. Genomic sequencing of one of these strains, isolated from a bovine in 2015, revealed a IncFII plasmid of 60 Kb encoding anarnBCADTEFoperon closely related toKluyvera ascorbatahomologs. This element, named pArnT1, was cured by ethidum bromide and lost in parallel to colistin resistance. This work reveals that, besidesmcrgenes and chromosomal mutations, mobilization ofarnBCADTEFoperon represents a colistin resistance mechanism whose spread and relevance for public health should be carefully surveyed.

Abstract Importance

Colistin is an old antibiotic that has returned to first-line fighting against (Gram negative) microorganisms after pandemic rising of antimicrobial resistance. However, low susceptibility to colistin is also becoming spread, mainly by plasmid mobilization of one of the enzymes (encoded bymcrgenes) that modify covalently the external layer (the lipid A component of the lipopolysaccharide) of bacterial envelope, interfering antibiotic effectiveness. The second enzymatic system that performs envelope modification and confers colistin resistance when overexpressed is encoded byarnBCADTEFoperon, a set of seven genes with location restricted (up to now) to the chromosome of Gram negative bacteria. This work describes plasmid mobilization of this operon between enterobacteria, fromKluyveratoEscherichia coli, where aKluyvera-likearnBCADTEFoperon carried by pArnT1 might represent, besidesmcrgenes, a potential risk for antimicrobial therapy and might require careful surveillance.
Necator americanus Ancylostoma secreted protein-2 (Na-ASP-2) selectively binds an ascaroside (ascr#3)
Authors: El Atab Ola , Darwiche Rabih , Truax Nathanyal J. , Schneiter Roger , Hull Kenneth G. , Romo Daniel , Asojo Oluwatoyin A.
Published: August 2020

During their infective stages, hookworms release excretory-secretory (E-S) products, including small molecules and proteins, to help evade and suppress the host’s immune system. Small molecules found in E-S products of mammalian hookworms include nematode derived metabolites like ascarosides, which are composed of the sugar ascarylose linked to a fatty acid side chain. Ascarosides play vital roles in signaling, development, reproduction, and survival. The most abundant proteins found in hookworm E-S products are members of the protein family known asAncylostomasecreted protein (ASP). ASP belongs to the SCP/TAPS (sperm-coating protein / Tpx / antigen 5 / pathogenesis related-1 / Sc7) superfamily of proteins, members of which have previously been shown to bind to eicosanoids and fatty acids. These molecules are structurally similar to the fatty acid moieties of ascarosides. The objective of this study was to determine if the hookworm ASP;N. americanus Ancylostomasecreted protein 2 (Na-ASP-2) binds to the ascarosides or their fatty acid moieties. We describe investigations of our hypothesis that there is a functional relationship between the major secreted proteins and signaling small molecules found in hookworm E-S products. To accomplish this, several ascarosides and their fatty acid moieties were synthesized and tested forin vitrobinding toNa-ASP-2 using a ligand competition assay and microscale thermophoresis. Our results reveal that the fatty acid moieties of the ascarosides, bind specifically to the palmitic acid binding cavity ofNa-ASP-2. Additionally, ascr#3, an ascaroside that is present in mammalian hookworm E-S products binds to the palmitic acid binding cavity ofNa-ASP-2, whereas oscr#10 which is not found in hookworm E-S products does not bind. Future studies are required to determine the structural basis of ascaroside binding byNa-ASP-2 and to understand the physiological significance of these observations.
Driving Hierarchical Collagen Fiber Formation for Functional Tendon, Ligament, and Meniscus Replacement
Authors: Puetzer Jennifer L. , Ma Tianchi , Sallent Ignacio , Gelmi Amy , Stevens Molly M.
Published: August 2020

Hierarchical collagen fibers are the primary source of strength in musculoskeletal tendons, ligaments, and menisci. It has remained a challenge to develop these large fibers in engineered replacements orin vivoafter injury. The objective of this study was to investigate the ability of restrained cell-seeded high density collagen gels to drive hierarchical fiber formation for multiple musculoskeletal tissues. We found boundary conditions applied to high density collagen gels were capable of driving tenocytes, ligament fibroblasts, and meniscal fibrochondrocytes to develop native-sized hierarchical collagen fibers 20-40 µm in diameter. The collagen fibers organize similar to native collagen with native fibril banding patterns and hierarchical fiber bundles 50-350 µm in diameter by 6 weeks. Mirroring fiber organization, tensile properties of restrained samples improved significantly with time, reaching ∼1 MPa. Additionally, tendon, ligament, and meniscal cells produced significantly different sized fibers, different degrees of crimp, and different GAG concentrations, which corresponded with respective native tissue. To our knowledge, these are some of the largest, most organized fibers produced to datein vitro. Further, cells produced tissue specific hierarchical fibers, suggesting this system is a promising tool to better understand cellular regulation of fiber formation to better stimulate itin vivoafter injury.
Impact of community-based business model and competitive advantage on exports: evidence from diamond industry
Authors: Kumar Shubham , Kumar Deepak , Sengupta Keya , Giri Tapas Kumar
Published: August 2020

Purpose

This study aims to examine the altering paradigms for two specific characteristics of the international diamond industry: community-based business model and competitive advantage and their impact and interaction effect.

Design/methodology/approach

This study uses global value chain (GVC) analysis to understand the industry characteristics, social impacts and disruption in the international diamond industry. Further, normalized revealed comparative advantage is used to measure the competitiveness of different countries over time. Finally, stochastic frontier analysis is used to test the impact of the community-based business model and competitiveness on exports and estimate the technical efficiency.

Findings

The international diamond industry is witnessing changes in the business model, competitiveness, processes, policies and consumer behavior. While competitive advantage and community have a positive impact on exports, the relationship between competitive advantage and exports gets negatively moderated by the community. Further, insights from the GVC analysis indicate that though the industry is facing several disruptions and challenges, it has shown the unique quality of community reconfiguration and relocation.

Originality/value

This paper provides insights into the diamond industry facing multiple disruptions at various stages of GVC and contributes to the literature on international trade, community-based business models and GVC.
The legacy of stress: Coral bleaching impacts reproduction years later
Authors: Johnston Erika C. , Counsell Chelsie W. W. , Sale Tayler L. , Burgess Scott C. , Toonen Robert J.
Published: August 2020

The extent to which populations persist under environmental stress depends on the reproductive output of individuals that survive the stress. In coral systems, corals bleach in response to stress from elevated water temperature. However, little is known of the extent to which thermal stress impairs the reproductive capacity of the survivors over the following years, limiting the capacity to predict how populations will persist in the Anthropocene.

Using histology to quantify the abundance and size of oocytes and spermaries per polyp, we tested how bleaching impairs the reproductive response of the coral Pocillopora meandrina over two reproductive seasons following the 2015 mass bleaching event in the Hawaiian Islands.

We found that smaller colonies not only had a greater probability of bleaching but also suffered greater reproductive impacts over a longer time. In contrast, larger colonies generated comparable reproductive output regardless of bleaching severity, although bleached colonies generated smaller oocytes the year after bleaching.

These results show that reproductive impacts of bleaching are more complex and size‐specific than commonly assumed. Therefore, estimates of bleaching mortality may underestimate the true impact of thermal stress on populations, especially as populations lose larger individuals from repeated and co‐occurring stressors.

A free Plain Language Summary can be found within the Supporting Information of this article.
Isotope analyses of amino acids in fungi and fungal feeding Diptera larvae allow differentiating ectomycorrhizal and saprotrophic fungi‐based food chains
Authors: Pollierer Melanie M. , Scheu Stefan , Tiunov Alexei V.
Published: August 2020

Both ectomycorrhizal (ECM) and saprotrophic fungi are fundamental to carbon and nutrient dynamics in forest ecosystems; however, the relative importance of these different fungal functional groups for higher trophic levels of the soil food web is virtually unknown.

To explore differences between fungal functional groups and their importance for higher trophic levels, we analysed isotopic composition of nitrogen and carbon in amino acids (AAs) and bulk tissue of leaf litter, fungi and fungal‐feeding Diptera larvae.

By accounting for isotopic variability of utilized substrates, compound‐specific isotope analyses of nitrogen in AAs yielded more realistic results for the trophic position of fungi than bulk isotope analyses, with converging trophic positions of saprotrophic and ECM fungi.

Saprotrophic and ECM fungi possessed different AA δ13C signatures separating fungal functional groups and their consumers in fingerprinting approaches, thereby allowing to trace energy fluxes from these basal resources to higher trophic levels.

A pronounced isotopic fractionation even in essential/source AAs of fungal‐feeding Diptera larvae necessitates further studies on tissue‐/compound‐specific isotopic differences in fungi and on potential supplementation by gut micro‐organisms.

The results highlight the potential of compound‐specific isotope analysis of amino acids to identify and integrate contributions of different fungal functional groups to higher trophic levels in soil food webs.

A free Plain Language Summary can be found within the Supporting Information of this article.
Waterbird seed‐dispersal networks are similarly nested but less modular than those of frugivorous birds, and not driven by functional traits
Authors: Sebastián‐González Esther , Lovas‐Kiss Ádám , Soons Merel B. , van den Broek Bas , Green Andy J.
Published: August 2020

Frugivory is widely recognized as vital for the dispersal of many plants. Moreover, plant species and their frugivorous dispersers form seed‐dispersal assemblages whose structure has important implications for the persistence and stability of the community. However, dispersal interactions between plants and non‐frugivorous animal groups such as waterbirds remain largely understudied.

We aimed to characterize the structure of waterbird seed‐dispersal networks, assess if this structure is similar to that of networks formed between frugivorous birds and fleshy‐fruited plants, and identify bird or plant functional traits important for the maintenance of network structure.

We used network analyses and data from four community‐level studies on waterbird gut contents, including 12 bird and 88 plant species. We compared the network structure of waterbirds to those from previous studies of frugivorous birds. We also related the contribution of each species to the network structure with functional traits (e.g. size, habitat requirements, diet).

Waterbird seed‐dispersal networks are similarly nested (i.e. specialists interact with a subset of those species that interact with generalists) but less modular (i.e. fewer semi‐independent groups of highly interacting species) than those of frugivores. Dabbling ducks, diving ducks and rallids did not separate into modules. The contribution of bird or plant species to network structure was not related to any functional trait.

Seed‐dispersal networks of waterbirds share some organizational patterns with those of frugivores, but the underlying processes are not related to functional traits. This is probably related to fundamental differences between waterbirds and frugivores in how seeds are ingested. Differences in the functional role of waterbirds for seed dispersal are likely driven by other processes such as differences in population size, movement, ecology or gut processing of seeds.

A free Plain Language Summary can be found within the Supporting Information of this article.
Root herbivory controls the effects of water availability on the partitioning between above‐ and below‐ground grass biomass
Authors: Franco André L. C. , Gherardi Laureano A. , de Tomasel Cecilia M. , Andriuzzi Walter S. , Ankrom Katharine E. , Bach Elizabeth M. , Guan Pingting , Sala Osvaldo E. , Wall Diana H.
Published: August 2020

The fraction of primary productivity allocated below‐ground accounts for a larger flow of carbon than above‐ground productivity in most grassland ecosystems. Here, we addressed the question of how root herbivory affects below‐ground allocation of a dominant shortgrass prairie grass in response to water availability. We predicted that high levels of root herbivory by nematodes, as seen under extreme drought in sub‐humid grasslands, would prevent the high allocation to root biomass normally expected in response to low water availability.

We exposed blue gramaBouteloua gracilis, which accounts for most of the net primary productivity in the shortgrass steppe of the central and southern Great Plains, to three levels of water availability from extreme low to intermediate and extreme high crossed with a gradient of root­herbivore per cent abundance relative to the total nematode community in soil microcosms.

As hypothesized, the effect of water availability on below‐ground biomass allocation was contingent on the proportion of root herbivores in the nematode community. The relationship between below‐ground biomass allocation and water availability was negative in the absence of root herbivory, but tended to reverse with increasing abundance of root feeders. Increasing abundance of root‐feeding nematodes prevented grasses from adjusting their allocation patterns towards root mass that would, in turn, increase water uptake under dry conditions. Therefore, below‐ground trophic interactions weakened plant responses and increased the negative effects of drought on plants.

Our work suggests that plant responses to changes in precipitation result from complex interactions between the direct effect of precipitation and indirect effects through changes in the below‐ground trophic web. Such complex responses challenge current predictions of increasing plant biomass allocation below‐ground in water‐stressed grasslands, and deserve further investigation across ecosystems and in field conditions.

A freePlain Language Summarycan be found within the Supporting Information of this article.
Dynamic shifts in social network structure and composition within a breeding hybrid population
Authors: Zonana David M. , Gee Jennifer M. , Breed Michael D. , Doak Daniel F.
Published: August 2020

Mating behaviour and the timing of reproduction can inhibit genetic exchange between closely related species; however, these reproductive barriers are challenging to measure within natural populations. Social network analysis provides promising tools for studying the social context of hybridization, and the exchange of genetic variation, more generally.

We test how social networks within a hybrid population of CaliforniaCallipepla californicaand Gambel's quailCallipepla gambeliichange over discrete periods of a breeding season. We assess patterns of phenotypic and genotypic assortment, and ask whether altered associations between individuals (association rewiring), or changes to the composition of the population (individual turnover) drive network dynamics. We use genetic data to test whether social associations and relatedness between individuals correlate with patterns of parentage within the hybrid population.

To achieve these aims, we combine RFID association data, phenotypic data and genomic measures with social network analyses. We adopt methods from the ecological network literature to quantify shifts in network structure and to partition changes into those due to individual turnover and association rewiring. We integrate genomic data into networks as node‐level attributes (ancestry) and edges (relatedness, parentage) to test links between social and parentage networks.

We show that rewiring of associations between individuals that persist across network periods, rather than individual turnover, drives the majority of the changes in network structure throughout the breeding season, and that the traits involved in phenotypic/genotypic assortment were highly dynamic over time. Social networks were randomly assorted based on genetic ancestry, suggesting weak behavioural reproductive isolation within this hybrid population. Finally, we show that the strength of associations within the social network, but not levels of genetic relatedness, predicts patterns of parentage.

Social networks play an important role in population processes such as the transmission of disease and information, yet there has been less focus on how networks influence the exchange of genetic variation. By integrating analyses of social structure, phenotypic assortment and reproductive outcomes within a hybrid zone, we demonstrate the utility of social networks for analysing links between social context and gene flow within wild populations.
Arbuscular mycorrhizal symbiosis increases phosphorus uptake and productivity of mixtures of maize varieties compared to monocultures
Authors: Wang Xin‐Xin , Hoffland Ellis , Feng Gu , Kuyper Thomas W.
Published: August 2020

Ecological intensification seeks to achieve crop yield increases by intensifying complementary or facilitative interactions between plant species or varieties. Different species of arbuscular mycorrhizal fungi (AMF) exhibit niche differentiation and show selectivity towards certain plants, which can further enhance complementarity. It is not clear whether in the presence of one AMF species, where mycelial networks connect crop species, opportunities for complementarity effects may be reduced.

We grew monocultures and mixtures of maize varieties in a greenhouse with one species of AMF, Funneliformis mosseae, during two consecutive years to investigate whether under such conditions the mycorrhizal symbiosis would affect complementarity and overyielding compared to non‐mycorrhizal plants.

Variety mixtures showed increased phosphatase activity and mycorrhizal colonization, enhanced phosphorus uptake and overyielding when plants were mycorrhizal. There was no overyielding when plants were non‐mycorrhizal. The increase in relative yield total was due to complementarity effects.

Synthesis and applications. Our study implies that appropriate agricultural management that enhances mycorrhizal fungal contribution to ecosystem services may result in overyielding in terms of yield or phosphorus uptake through mixing varieties within one crop species.
Hypothesis: The potential therapeutic role of nicorandil in COVID‐19
Authors: Ashour Hend , Elsayed Mohamed H. , Elmorsy Soha , Harb Inas A.
Published: August 2020

At present, there is yet no specific antiviral treatment or immunization against the newly identified human severe acute respiratory syndrome virus (SARS‐CoV2) that results in a rapidly progressive pandemic coronavirus disease 2019 (COVID‐19). We believe in a crucial need for a clinical strategy to counteract this viral pandemic based on the known pathogenesis throughout the disease course. Evidence suggests that exaggerated patient's inflammatory response and oxidative stress are likely to aggravate the disease pathology. The resulting endothelial dysfunction further induces fibrosis and coagulopathy. These disturbances can generate severe acute respiratory distress syndrome (ARDS) that can progress into respiratory and circulatory failure. Nicorandil is an anti‐anginal vasodilator drug acts by increasing nitric oxide bioavailability and opening of the KATP channel. Recently, nicorandil has been recognized to possess multiple protective effects against tissue injury. Here, we address a possible modulatory role of nicorandil against COVID‐19 pathogenesis. We hypothesise nicorandil would be an effective form of adjuvant therapy against COVID‐19.
Effects of maternal high‐fat/high sucrose diet on hepatic lipid metabolism in rat offspring
Authors: Ingvorsen Camilla , Lelliott Christopher J. , Brix Susanne , Hellgren Lars I.
Published: August 2020

Maternal obesity and/or high‐fat diet during pregnancy predispose the offspring to metabolic disease. It is however unclear how pre‐natal and post‐natal exposure respectively affect the risk of hepatic steatosis and the trajectory towards non‐alcoholic steatohepatitis in the offspring. We investigate hepatic lipid metabolism and how these factors are related to metabolic outcome in new born and young rats. Rat dams were exposed to a high‐fat/high sucrose (HFHS) diet for 17 weeks prior to mating and during pregnancy. After birth, female offspring were killed and male offspring were cross‐fostered, creating four groups; Control‐born pups lactated by control (CC) or HFHS dams (CH) and HFHS‐born pups lactated by control (HC) or HFHS dams (HH). At 4 weeks of age, pups were killed and metabolic markers in plasma were assayed, together with hepatic lipid composition and expression of relevant genes. Female HFHS neonates had smaller livers at birth (P < .05), a reduced hepatic lipid content (P < .05) and altered lipid composition. The post‐natal environment dominated the metabolic profile in the male offspring at 4 weeks of age. Offspring exposed to a HFHS environment post‐natally had increased adiposity (P < .0001), increased hepatic triacylglycrol accumulation (P < .0001), and an altered lipid profile with elevated n‐6 polyunsaturated fatty acid (PUFA) levels (P < .0001) and a reduction in ceramide (P < .001) and monounsaturated fatty acid (MUFA) (P < .0001). In summary, maternal HFHS diet during gestation affects the hepatic lipid profile in neonates. The pre‐natal exposure becomes less pronounced in young male offspring at 4 weeks of age, where the post‐natal diet has the largest impact.
Professional boundary struggles in the context of healthcare change: the relational and symbolic constitution of nursing ethos in the space of possible professionalisation
Authors: Ernst Jette
Published: August 2020

The paper draws on Bourdieu’s conceptualisation of the symbolic order and his little used concept of ethos in order to gain novel understandings of boundary struggles between nursing and medicine as well as internally in nursing. The constituents of boundary struggles are analysed in the context of healthcare transformation, focusing on organisational, institutional and political boundary undertakings. Changing conditions for boundary demarcations and professionalisation include a preference for evidence‐based knowledge and practice, seen as a remedy against common problems in health care. The paper shows how nurses use the changes in ‘the space of possible professionalisation’ in their struggle for professionalisation when they expand their scope of practice and embark on what is conceptualised as a curing ethos, where nursing is understood as a discipline performing practices that lead to cure. However, this is repudiated by the medical profession at all levels. Moreover, curing stands opposed to the caring ethos in nursing and boundary struggles surface as ‘ethos confrontation’ between caring‐ and curing‐oriented nurses in practice. The boundary struggles analysed in this paper raise important questions about healthcare manageability and the development of sustainable professional environments.
Paradoxes of professional autonomy: a qualitative study of U.S. neonatologists from 1978‐2017
Authors: Rozier Michael D. , Willison Charley E. , Anspach Renee R. , Howell Joel D. , Greer Ann L. , Greer Scott L.
Published: August 2020

The professional autonomy of physicians often requires they take responsibility for life and death decisions, but they must also find ways to avoid bearing the full weight of such decisions. We conducted in‐person, semi‐structured interviews with neonatologists (n = 20) in four waves between 1978 and 2017 in a single Midwestern U.S. city. Using open coding analysis, we found over time that neonatologists described changes in their sense of professional autonomy and responsibility for decisions with life and death consequences. Through the early 1990s, as neonatology consolidated as a profession, physicians simultaneously enjoyed high levels of professional discretion and responsibility and were often constrained by bioethics and the law. By 2010s, high involvement of parents and collaboration with multiple subspecialties diffused the burden felt by individual practitioners, but neonatology’s professional autonomy was correlatively diminished. Decision‐making in the NICU over four decades reveal a complex relationship between the professional autonomy of neonatologist and the burden they bear, with some instances of ceding autonomy as a protective measure and other situations of unwelcomed erosion of professional autonomy that neonatologists see as complicating provision of care.
De novo assemblies of Luffa acutangula and Luffa cylindrica genomes reveal an expansion associated with substantial accumulation of transposable elements
Authors: Pootakham Wirulda , Sonthirod Chutima , Naktang Chaiwat , Nawae Wanapinun , Yoocha Thippawan , Kongkachana Wasitthee , Sangsrakru Duangjai , Jomchai Nukoon , U‐thoomporn Sonicha , Sheedy John R. , Buaboocha Jarunee , Mekiyanon Supat , Tangphatsornruang Sithichoke
Published: August 2020

Luffa spp. (sponge gourd or ridge gourd) is an economically important vegetable crop widely cultivated in China, India and Southeast Asia. Here, we employed PacBio long‐read single‐molecule real‐time (SMRT) sequencing to perform de novo genome assemblies of two commonly cultivated Luffa species, L. acutangula and L. cylindrica. We obtained preliminary draft genomes of 734.6 Mb and 689.8 Mb with scaffold N50 of 786,130 and 578,616 bases for L. acutangula and L. cylindrica, respectively. We also applied long‐range Chicago and HiC techniques to obtain the first chromosome‐scale whole‐genome assembly of L. acutangula. The final assembly contained 13 pseudomolecules, corresponding to the haploid chromosome number in Luffa spp. (1n = 13, 2n = 26). The sizes of the assembled Luffa genomes are approximately twice as large as the genome assemblies of related Cucurbitaceae. A large proportion of L. acutangula (62.17%; 456.69 Mb) and L. cylindrica (56.78%; 391.65 Mb) genome assemblies contained repetitive elements. Phylogenetic analyses revealed that the substantial accumulation of transposable elements likely contributed to the expansion of the Luffa genomes. We also investigated alternative splicing events in Luffa using full‐length transcript sequences obtained from PacBio Isoform Sequencing (Iso‐seq). While the predominant form of alternative splicing in most plant species examined was intron retention, alternative 3’ acceptor site selection appeared to be a major event observed in Luffa. High‐quality genome assemblies for L. acutangula and L. cylindrica reported here provide valuable resources for Luffa breeding and future genetics and comparative genomics studies in Cucurbitaceae.
Scaling methods in ecological modelling
Authors: Fritsch Matthias , Lischke Heike , Meyer Katrin M.
Published: August 2020

Modelling is often confronted with scaling problems, because modelling—directly or indirectly—always implies scaling. This is because models simplify. Simplification usually means aggregation, and aggregation is a scaling process. As scaling cannot be avoided in modelling, it should carefully be addressed and resolved, at least to the degree possible.

In this paper, we give an overview of scaling approaches in ecological modelling. We propose to classify scaling approaches into pre‐model scaling, in‐model scaling and post‐model scaling depending on the timing of the scaling relative to the main modelling process.

We show general approaches, examples and potential application problems for each category. We suggest that scaling problems might be more widespread than previously thought. These scaling problems are matched with a range of solutions, but often these solutions will have to be adapted and tailored to the specific scaling case.

Thus, we recommend that ecologists be aware of scaling challenges especially where models do not explicitly aim at scaling. Developing general test systems for scaling methods may help to broaden and enhance the application of scaling methods in ecology.
Testicular Lmcd1 regulates phagocytosis by Sertoli cells through modulation of NFAT1/Txlna signaling pathway
Authors: Jin Xiaohang , Zhang Sheng , Ding Tianbing , Zhao Pengtao , Zhang Chunli , Zhang Yuxing , Li Wei
Published: August 2020

Increased oxidative stress is well known to cause testicular dysfunction in aging males, but the detailed relationships between aging, oxidative stress, and testicular function remain to be elucidated. LIM and cysteine‐rich domains 1 (LMCD1) regulates fundamentally cellular process by interacting with transcription factors. A recent study has identified Lmcd1 as one of the most upregulated nuclear proteins associated with Sertoli cell (SC) differentiation, raising the possibility that testicular actions of LMCD1 are likely to take place. Herein, we reported that LMCD1 was exclusively expressed in the nuclei of SCs. This expression was regulated by TNF‐α signaling produced by apoptotic germ cells (GCs) and was suppressed by oxidative stress in a STAT3‐dependent manner. Ablation of endogenous LMCD1 expression caused lipid accumulation and senescence in GC co‐incubated SCs. Using a previously validated in vivo siRNA approach, we showed that LMCD1 depletion significantly impaired male fertility by inducing oligozoospermia and asthenospermia. Mechanistically, LMCD1 upregulation was associated with the nuclear enrichment of the nuclear factor of activated T cells 1 (NFAT1), a core component of Ca2+/calmodulin‐dependent pathway. LMCD1 facilitated the dephosphorylation and nuclear translocation of NFAT1, which consequently expedited the transactivation of Txlna, a binding partner of the syntaxin family essential for testicular phagocytosis, and thus promoted the removal of apoptotic GCs by phagocytic SCs. Collectively, LMCD1 may operate as a novel pretranscriptional integrator linking SC phagocytosis, lipid homeostasis, and cell senescence.
Acute Alcohol Intoxication Impairs Sonic Hedgehog‐Gli1 Signaling and Activation of Primitive Hematopoietic Precursor Cells in the Early Stage of Host Response to Bacteremia
Authors: Shi Xin , Simms Kevin J. , Zhang Ping
Published: August 2020

Background

Activation of hematopoietic stem cells [HSCs, lineage(lin)−stem cell growth factor receptor (c‐kit)+stem cell antigen‐1(Sca‐1)+, or LKS cells in mice] is critical for initiating the granulopoietic response. This study determined the effect of alcohol exposure on sonic hedgehog (SHH) signaling in the regulation of HSC activation during bacteremia.

Methods

Acute alcohol intoxication was induced in mice by intraperitoneal (i.p.) injection of 20% alcohol (5 g alcohol/kg body weight). Control mice received i.p. saline. Thirty minutes later, mice were intravenously (i.v.) injected with Escherichia coli (E. coli, 1 to 5 × 107 CFUs/mouse) or saline.

Results

SHH expression by lineage‐negative bone marrow cells (BMCs) was significantly increased 24 hours after E. coli infection. Extracellular signal‐regulated kinase 1/2 (ERK1/2)‐specificity protein 1 (Sp1) signaling promotes SHH expression. ERK1/2 was markedly activated in BMCs 8 hours following E. coli infection. Alcohol suppressed both the activation of ERK1/2 and up‐regulation of SHH expression following E. coli infection. E. coli infection up‐regulated GLI family zinc finger 1 (Gli1) gene expression by BMCs and increased Gli1 protein content in LKS cells. The extent of Gli1 expression was correlated with the activity of proliferation in LKS cells. Alcohol inhibited up‐regulation of Gli1 expression and activation of LKS cells in response to E. coli infection. Alcohol also interrupted the granulopoietic response to bacteremia.

Conclusion

These data show that alcohol disrupts SHH‐Gli1 signaling and HSC activation in the early stage of the granulopoietic response, which may serve as an important mechanism underlying the impairment of immune defense against bacterial infection in host excessively consuming alcohol.