Adaptive constraints at the range edge of a widespread and expanding invasive plant.

Identifying the factors that facilitate and limit invasive species' range expansion has both practical and theoretical importance, especially at the range edges. Here, we used reciprocal common garden experiments spanning the North/South and East/West range that include the North American core, intermediate and range edges of the globally invasive plant, Johnsongrass (Sorghum halepense) to investigate the interplay of climate, biotic interactions (i.e. competition) and patterns of adaptation. Our results suggest that the rapid range expansion of Johnsongrass into diverse environments across wide geographies occurred largely without local adaptation, but that further range expansion may be restricted by a fitness trade-off that limits population growth at the range edge. Interestingly, plant competition strongly dampened Johnsongrass growth but did not change the rank order performance of populations within a garden, though this varied among gardens (climates). Our findings highlight the importance of including the range edge when studying the range dynamics of invasive species, especially as we try to understand how invasive species will respond to accelerating global changes.

Horsenettle (Solanum carolinense) fruit bacterial communities are not variable across fine spatial scales.

Fruit house microbial communities that are unique from the rest of the plant. While symbiotic microbial communities complete important functions for their hosts, the fruit microbiome is often understudied compared to other plant organs. Fruits are reproductive tissues that house, protect, and facilitate the dispersal of seeds, and thus they are directly tied to plant fitness. Fruit microbial communities may, therefore, also impact plant fitness. In this study, we assessed how bacterial communities associated with fruit of Solanum carolinense, a native herbaceous perennial weed, vary at fine spatial scales (<0.5 km). A majority of the studies conducted on plant microbial communities have been done at large spatial scales and have observed microbial community variation across these large spatial scales. However, both the environment and pollinators play a role in shaping plant microbial communities and likely have impacts on the plant microbiome at fine scales. We collected fruit samples from eight sampling locations, ranging from 2 to 450 m apart, and assessed the fruit bacterial communities using 16S rRNA gene amplicon sequencing. Overall, we found no differences in observed richness or microbial community composition among sampling locations. Bacterial community structure of fruits collected near one another were not more different than those that were farther apart at the scales we examined. These fine spatial scales are important to obligate out-crossing plant species such as S. carolinense because they are ecologically relevant to pollinators. Thus, our results could imply that pollinators serve to homogenize fruit bacterial communities across these smaller scales.

Suspension and expulsion in Colorado early care and education settings: Child, program, and community-level predictors.

Expulsion presents a significant risk in Early Care and Education (ECE) settings due to its association with early disadvantage and frequency of use. A statewide survey was conducted to characterize ECE suspension and expulsion (S/E) in Colorado. Child, program, and community-level factors were examined as predictors of S/E, alongside preventative intervention supports capable of reducing S/E. Six hundred and sixty three licensed child care programs participated in the survey, providing information on 19,848 enrolled children, 312 suspensions, and 74 expulsions. A series of multilevel hierarchical regressions were conducted, examining predictors for S/E. Children with IEPs/IFSPs were disproportionately suspended; 2-3-year-olds were disproportionately expelled; and boys, 5-6-year-olds, and children with disabilities were disproportionately suspended and expelled. Center-based programs, lower quality ratings, and "zero tolerance" policies predicted greater use of suspension. In contrast, school-district affiliation and knowledge of how to access infant and early childhood mental health consultation (IECMHC) decreased suspension. Lower levels of regional child poverty predicted higher use of expulsion. Affiliation with a school-district, IECMH consultant-led training, and use of quality coaches predicted decreased expulsion. This study identifies the need for ongoing protection for children with IEPs/ IFSPs and the preventative interventions that mitigate risk for S/E.

Introducción. La expulsión presenta un riesgo significativo en el marco del Temprano Cuidado y Educación (ECE) debido a su asociación con tempranas desventajas y la frecuencia de uso. Una encuesta a nivel estatal se llevó a cabo para caracterizar la suspensión y expulsión de ECE (S/E) en Colorado. Asuntos relacionados con el niño, el programa y de nivel comunitario se examinaron como factores de predicción de (S/E), junto con apoyos de intervención para prevenir, capaces de reducir S/E. Métodos. Participaron en la encuesta 663 programas de cuidado infantil autorizados, lo cual aportó información sobre 19,848 niños matriculados, 312 suspensiones y 74 expulsiones. Se llevó a cabo una serie de regresiones jerárquicas de niveles múltiples, examinando así los factores de predicción de S/E. Resultados. A los niños con participación en programas o planes IEP/IFSP se les suspendió de manera desproporcionada; niños entre los dos y tres años fueron desproporcionalmente expulsados; y varones de cinco a seis años, y niños con discapacidades fueron desproporcionalmente suspendidos y expulsados. Los programas con base en un centro, los más bajos puntajes de evaluación de la calidad y las políticas de 'tolerancia cero' predijeron el mayor uso de la suspensión. En contraste, la afiliación a un distrito escolar y el conocimiento de cómo tener acceso a la consulta de salud mental infantil y la temprana niñez (IECMHC) redujo las suspensiones. Los más bajos niveles de pobreza regional de niños predijeron el más alto uso de la expulsión. La afiliación a un distrito escolar, el entrenamiento de consultores de IECMH, así como el uso de entrenadores calificados predijeron una reducción de las expulsiones. Conclusiones. Este estudio identifica la necesidad de una continuada protección para niños en programas o planes IEP/IFSP y las intervenciones de prevención que mitigan el riesgo de S/E.

INTRODUCTION: L'expulsion présente un risque important pour les contextes de Soins Précoces et Education (en anglais Early Care and Education, abrégé ici ECE) du fait de son lien à un désavantage précoce et la fréquence de l'utilisation. Un sondage au niveau de l'état a été fait afin de caractériser la suspension ECE et l'expulsion (S/E) dans l'état du Colorado aux Etats-Unis. L'enfant, le programme et les facteurs aux niveau de la communauté ont été examinés en tant que facteurs de prédiction de la (S/E), en parallèle avec des soutiens d'une intervention préventive capable de réduire la S/E. Méthodes. 663 programmes de crèches accréditées ont participé au questionnaire, offrant des renseignements sur 19848 enfants inscrits, 312 suspensions et 74 expulsions. Une série de régressions hiérarchiques à niveaux multiples a été faite, examinant les facteurs de prédiction pour la S/E. Résultats. Les enfants avec des plans IEP/IFSP (Plan d'Enseignement Individualisé/Plan Individualisé de Service à la Famille) ont été suspendus de manière disproportionnée ; les enfants de deux à trois ans ont été expulsés de manière disproportionnée, et les enfants avec des handicaps ont été suspendus et expulsée de manière disproportionnée. Les programmes centres (centrés sur une condition), les cotes de qualité inférieure et les politiques de « zéro tolérance ¼ ont prédit une plus grande utilisation de la suspension. Par contre, l'affiliation à un district académique et des connaissances sur la manière d'accéder à la consultation de santé mentale du nourrisson et de la petite enfance (IECMHC) ont fait décroître le taux de suspension. Des niveaux plus bas de pauvreté de l'enfant régionale ont prédit une utilisation plus élevée de la suspension. L'affiliation à un district académique, la formation faite par un consultant IECMH et l'utilisation de formateurs de qualité ont prédit une expulsion moins élevée. Cette étude identifie le besoin de protection continue des enfants avec des plans IEP/IFSP et d'interventions préventives qui mitigent le risque de S/E.

Into the weeds: new insights in plant stress.

Weeds, plants that thrive in the face of disturbance, have eluded human's attempts at control for >12 000 years, positioning them as a unique group of extreme stress tolerators. The most successful weeds have a suite of traits that enable them to rapidly adapt to environments typified by stress, growing in hostile conditions or subject to massive destruction from agricultural practices. Through their ability to persist and adapt, weeds illuminate principles of evolution and provide insights into weed management and crop improvement. Here we highlight why the time is right to move beyond traditional model systems and leverage weeds to gain a deeper understanding of the mechanisms, adaptations, and genetic and physiological bases for stress tolerance.

Habitat Suitability and Establishment Limitations of a Problematic Liana.

The US native liana, poison ivy (Toxicodendron radicans), responsible for contact dermatitis in humans, is a competitive weed with great potential for expansion in disturbed habitats. To facilitate a better understanding of this threat, we sought to evaluate habitat suitability, population demography, and biotic interactions of poison ivy, using a series of complementary field studies in the two habitats where it most commonly occurs-forest interiors and edges. Of the 2500 seeds planted across both habitats, poison ivy initially colonized forest interiors (32% emergence) at a higher rate than edge habitats (16.5% emergence). However, forest interior seedlings were less likely to survive (interior n = 3; edge n = 15), which might be attributed to herbivore pressure when the seedlings were smaller in the less competitive forest interior. Once established, the poison ivy seedlings appeared to be more tolerant of herbivory, except that of large grazers such as deer. The early life stage of seedling emergence, survival, and establishment are critical in poison ivy success, with biotic pressure, especially from plant competition and deer, limiting recruitment. A suitable habitat of this expanding native liana would increase with increasing forest fragmentation, but might be buffered by the expanding deer population.

Acute Respiratory Failure With a Rare, Rapidly Progressing Pediatric Desmoid Tumor Anterior Mediastinal Mass.

ABSTRACT: We present an unusual case of a 6-year-old boy who presented with the sudden presence of left neck mass and acute hypoxemic respiratory failure, whose subsequent imaging demonstrated a previously undiagnosed anterior mediastinal mass (AMM) extending into the left neck. Biopsy of the mass was consistent with a desmoid tumor, which is a rare cause of AMM in children. Desmoid tumors are locally aggressive, often invading and enveloping surrounding tissues, but overall slow growing. The sudden growth of the neck mass suggests a very aggressive desmoid tumor, causing an unexpected respiratory compromise. Anterior mediastinal masses may cause symptoms by compressing the heart, great vessels, and airways. However, the patient may adapt and develop compensatory mechanisms to counter the compressive effects. Emergency care of the patient with an AMM who presents with acute respiratory distress includes optimizing oxygenation through promoting a calm environment, oxygenating while minimizing positive end-expiratory pressure, maintaining the patient's compensatory mechanisms by minimizing sedation and muscle relaxation, positioning the patient to minimize compressive effects of the mass on the vital thorax structures, and early consultation with pediatric specialists to develop a shared-emergency treatment strategy and to secure an expedited disposition to the appropriate venue of care.

Silkworm Silk Fiber Bundles as Improved In Vitro Scaffolds for Skeletal Muscle.

To mimic skeletal muscle tissues in vitro, native and transgenic spider silk/silkworm silks were seeded with C2C12 myoblasts to observe if these three-dimensional substrates are preferable to a traditional two-dimensional polystyrene cell culture surface. Silks were wound around an acrylic chassis to produce a novel, three-dimensional cell culture device with suspended muscle fibers that genetically and morphologically resemble native skeletal muscle tissue. The transgenic spider silk/silkworm silk has never before been studied for this application. Genetic expression verified skeletal muscle lineage and differentiation, while fluorescent imaging verified contractile protein synthesis. Genetic analysis also revealed an increase in expression of the Myh2 contractile protein gene on silkworm silks, particularly on the transgenic silk. Mechanical properties and protein secondary structure content of the silks indicated correlation between substrate properties and Myh2 gene expression. This increase in contractile protein gene expression suggests that biologically derived silk substrates that are suspended may be a preferable substrate for in vitro muscle modeling because of the proteinaceous character and mechanical flexibility of the silk.

Intraspecific, ecotypic and home climate variation in photosynthetic traits of the widespread invasive grass Johnsongrass.

Despite their near ubiquity across global ecosystems, the underlying mechanisms contributing to the success of invasive plants remain largely unknown. In particular, ecophysiological traits, which are fundamental to plants' performance and response to their environment, are poorly understood with respect to geographic and climate space. We evaluated photosynthetic trait variation among populations, ecotypes and home climates (i.e. the climates from the locations they were collected) of the widespread and expanding invader Johnsongrass (Sorghum halepense). We found that populations vary in the maximum net photosynthetic flux and the light-saturated net photosynthetic rate, and that agricultural and non-agricultural ecotypes vary in apparent quantum yield and water-use efficiency (WUE). We also found that populations from warmer home climates had lower dark respiration rates, light compensation points and WUEs. As Johnsongrass expands across the USA the abiotic and biotic environments are driving variation in its genetics, phenotypes and its underlying physiology. Our study demonstrates the importance of evaluating physiological traits in invasive plants, especially as they relate to home climates.

The Evolution of an Invasive Plant, Sorghum halepense L. ('Johnsongrass').

From noble beginnings as a prospective forage, polyploid Sorghum halepense ('Johnsongrass') is both an invasive species and one of the world's worst agricultural weeds. Formed by S. bicolor x S. propinquum hybridization, we show S. halepense to have S. bicolor-enriched allele composition and striking mutations in 5,957 genes that differentiate it from representatives of its progenitor species and an outgroup. The spread of S. halepense may have been facilitated by introgression from closely-related cultivated sorghum near genetic loci affecting rhizome development, seed size, and levels of lutein, a photochemical protectant and abscisic acid precursor. Rhizomes, subterranean stems that store carbohydrates and spawn clonal propagules, have growth correlated with reproductive rather than other vegetative tissues, and increase survival of both temperate cold seasons and tropical dry seasons. Rhizomes of S. halepense are more extensive than those of its rhizomatous progenitor S. propinquum, with gene expression including many alleles from its non-rhizomatous S. bicolor progenitor. The first surviving polyploid in its lineage in ∼96 million years, its post-Columbian spread across six continents carried rich genetic diversity that in the United States has facilitated transition from agricultural to non-agricultural niches. Projected to spread another 200-600 km northward in the coming century, despite its drawbacks S. halepense may offer novel alleles and traits of value to improvement of sorghum.

Home climate and habitat drive ecotypic stress response differences in an invasive grass.

Invasive plants and agricultural weeds are a ubiquitous and ever-expanding threat to biosecurity, biodiversity and ecosystem services. Many of these species are known to succeed through rapid adaptation to biotic and abiotic stress regimes, often in highly disturbed systems. Given the current state of evidence for selection of weedy genotypes via primary physiological stresses like drought, flooding, heat, cold and nutrient deficiency, we posit that adaptation to land management regimes which comprise suites of these stresses can also be expected. To establish this link, we tested adaptation to water and nutrient stresses in five non-agricultural and five agricultural populations of the invader Johnsongrass (Sorghum halepense) sampled across a broad range of climates in the USA. We subjected seedlings from each population to factorial drought and nutrient stresses in a common garden greenhouse experiment. Agricultural and non-agricultural ecotypes did not respond differently to experimentally applied stresses. However, non-agricultural populations from more drought-prone and nutrient-poor locations outperformed their agricultural counterparts in shoot allocation and chlorophyll production, respectively. We also found evidence for root allocation adaptation to hotter climates, in line with other C4 grasses, while greater adaptation to drought treatment was associated with soil organic carbon (SOC)-rich habitats. These findings imply that adaptation to land-use types can interact with other macrohabitat parameters, which will be fluctuating in a changing climate and resource-needy world. We see that invasive plants are poised to take on novel habitats within their introduced ranges, leading to complications in the prevention and management of their spread.

Effectiveness of emergency physician determinations of the need for thrombolytic therapy in acute stroke.

An increased emphasis on stroke care has led to a proliferation of specialized stroke teams despite relatively few trials demonstrating their efficacy. Our academic stroke center incorporated a unique setup allowing for the comparison between stroke teams and emergency physicians. During weekday working hours, a stroke team would respond to the emergency department for stroke activations. During all other times, the emergency physician caring for the patient would make all treatment decisions. We sought to determine whether there was any difference in treatment and outcomes between these two groups. We conducted a retrospective review of all stroke activations from January 2015 to June 2016 and compared the thrombolytic administration rates, modified Rankin Scale (mRS) at discharge, and change in National Institutes of Health Stroke Scale (NIHSS). A total of 415 stroke activations were identified. Of those, 69 of 262 patients (26.3%) seen by emergency physicians and 60 of 153 patients (39.2%) seen by neurologists received thrombolysis (P = 0.006). No significant difference was found in the discharge mRS or change in NIHSS between the two groups. Emergency physicians administered significantly less thrombolytics than did neurologists. No significant difference was observed in outcomes, including mRS and admission-to-discharge change in NIHSS.

Invasive plants negatively impact native, but not exotic, animals.

Despite our growing understanding of the impacts of invasive plants on ecosystem structure and function, important gaps remain, including whether native and exotic species respond differently to plant invasion. This would elucidate basic ecological interactions and inform management. We performed a meta-analytic review of the effects of invasive plants on native and exotic resident animals. We found that invasive plants reduced the abundance of native, but not exotic, animals. This varied by animal phyla, with invasive plants reducing the abundance of native annelids and chordates, but not mollusks or arthropods. We found dissimilar impacts among "wet" and "dry" ecosystems, but not among animal trophic levels. Additionally, the impact of invasive plants increased over time, but this did not vary with animal nativity. Our review found that no studies considered resident nativity differences, and most did not identify animals to species. We call for more rigorous studies of invaded community impacts across taxa, and most importantly, explicit consideration of resident biogeographic origin. We provide an important first insight into how native and exotic species respond differently to invasion, the consequences of which may facilitate cascading trophic disruptions further exacerbating global change consequences to ecosystem structure and function.

Effect of growth media and phase on Raman spectra and discrimination of mycobacteria.

When developing a Raman spectral library to identify bacteria, differences between laboratory and real world conditions must be considered. For example, culturing bacteria in laboratory settings is performed under conditions for ideal bacteria growth. In contrast, culture conditions in the human body may differ and may not support optimized bacterial growth. To address these differences, researchers have studied the effect of conditions such as growth media and phase on Raman spectra. However, the majority of these studies focused on Gram-positive or Gram-negative bacteria. This article focuses on the influence of growth media and phase on Raman spectra and discrimination of mycobacteria, an acid-fast genus. Results showed that spectral differences from growth phase and media can be distinguished by spectral observation and multivariate analysis. Results were comparable to those found for other types of bacteria, such as Gram-positive and Gram-negative. In addition, the influence of growth phase and media had a significant impact on machine learning models and their resulting classification accuracy. This study highlights the need for machine learning models and their associated spectral libraries to account for various growth parameters and stages to further the transition of Raman spectral analysis of bacteria from laboratory to clinical settings.

Considering weed management as a social dilemma bridges individual and collective interests.

Weeds pose severe threats to agricultural and natural landscapes worldwide. One major reason for the failure to effectively manage weeds at landscape scales is that current Best Management Practice guidelines, and research on how to improve such guidelines, focus too narrowly on property-level management decisions. Insufficiently considered are the aggregate effects of individual actions to determine landscape-scale outcomes, or whether there are collective practices that would improve weed management outcomes. Here, we frame landscape-scale weed management as a social dilemma, where trade-offs occur between individual and collective interests. We apply a transdisciplinary system approach-integrating the perspectives of ecologists, evolutionary biologists and agronomists into a social science theory of social dilemmas-to four landscape-scale weed management challenges: (i) achieving plant biosecurity, (ii) preventing weed seed contamination, (iii) maintaining herbicide susceptibility and (iv) sustainably using biological control. We describe how these four challenges exhibit characteristics of 'public good problems', wherein effective weed management requires the active contributions of multiple actors, while benefits are not restricted to these contributors. Adequate solutions to address these public good challenges often involve a subset of the eight design principles developed by Elinor Ostrom for 'common pool social dilemmas', together with design principles that reflect the public good nature of the problems. This paper is a call to action for scholars and practitioners to broaden our conceptualization and approaches to weed management problems. Such progress begins by evaluating the public good characteristics of specific weed management challenges and applying context-specific design principles to realize successful and sustainable weed management.

Simultaneous isolation and label-free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy.

The traditional bacterial identification method of growing colonies on agar plates can take several days to weeks to complete depending on the growth rate of the bacteria. Successfully decreasing this analysis time requires cell isolation followed by identification. One way to decrease analysis time is by combining dielectrophoresis (DEP), a common technique used for cell sorting and isolation, and Raman spectroscopy for cell identification. DEP-Raman devices have been used for bacterial analysis, however, these devices have a number of drawbacks including sample heating, cell-to-electrode proximity that limits throughput and separation efficiency, electrode fouling, or inability to address sample debris. Presented here is a contactless DEP-Raman device to simultaneously isolate and identify particles from a mixed sample while avoiding common drawbacks associated with other DEP designs. Using the device, a mixed sample of bacteria and 3 µm polystyrene spheres were isolated from each other and a Raman spectrum of the trapped bacteria was acquired, indicating the potential for cDEP-Raman devices to decrease the analysis time of bacteria.

Identification of Differentially Methylated Sites with Weak Methylation Effects.

Deoxyribonucleic acid (DNA) methylation is an epigenetic alteration crucial for regulating stress responses. Identifying large-scale DNA methylation at single nucleotide resolution is made possible by whole genome bisulfite sequencing. An essential task following the generation of bisulfite sequencing data is to detect differentially methylated cytosines (DMCs) among treatments. Most statistical methods for DMC detection do not consider the dependency of methylation patterns across the genome, thus possibly inflating type I error. Furthermore, small sample sizes and weak methylation effects among different phenotype categories make it difficult for these statistical methods to accurately detect DMCs. To address these issues, the wavelet-based functional mixed model (WFMM) was introduced to detect DMCs. To further examine the performance of WFMM in detecting weak differential methylation events, we used both simulated and empirical data and compare WFMM performance to a popular DMC detection tool methylKit. Analyses of simulated data that replicated the effects of the herbicide glyphosate on DNA methylation in Arabidopsis thaliana show that WFMM results in higher sensitivity and specificity in detecting DMCs compared to methylKit, especially when the methylation differences among phenotype groups are small. Moreover, the performance of WFMM is robust with respect to small sample sizes, making it particularly attractive considering the current high costs of bisulfite sequencing. Analysis of empirical Arabidopsis thaliana data under varying glyphosate dosages, and the analysis of monozygotic (MZ) twins who have different pain sensitivities-both datasets have weak methylation effects of <1%-show that WFMM can identify more relevant DMCs related to the phenotype of interest than methylKit. Differentially methylated regions (DMRs) are genomic regions with different DNA methylation status across biological samples. DMRs and DMCs are essentially the same concepts, with the only difference being how methylation information across the genome is summarized. If methylation levels are determined by grouping neighboring cytosine sites, then they are DMRs; if methylation levels are calculated based on single cytosines, they are DMCs.

Epigenetic regulation - contribution to herbicide resistance in weeds?

Continuous use of herbicides has resulted in the evolution of resistance to all major herbicide modes of action worldwide. Besides the well-documented cases of newly acquired resistance through genetic changes, epigenetic regulation may also contribute to herbicide resistance in weeds. Epigenetics involves processes that modify the expression of specific genetic elements without changes in the DNA sequence, and play an important role in re-programming gene expression. Epigenetic modifications can be induced spontaneously, genetically or environmentally. Stress-induced epigenetic changes are normally reverted soon after stress exposure, although in specific cases they can also be carried over multiple generations, thereby having a selective benefit. Here, we provide an overview of the basis of epigenetic regulation in plants and discuss the possible effect of epigenetic changes on herbicide resistance. The understanding of these epigenetic changes would add a new perspective to our knowledge of environmental and management stresses and their effects on the evolution of herbicide resistance in weeds. © 2017 Society of Chemical Industry.

Climatic niche shifts are common in introduced plants.

Our understanding of how climate influences species distributions and our ability to assess the risk of introduced species depend on the assumption that species' climatic niches remain stable across space and time. While niche shifts have been detected in individual invasive species, one assessment of ~50 plants in Europe and North America concluded that niche shifts were rare, while another concluded the opposite. These contradictory findings, limited in species number and geographic scope, leave open a need to understand how often introduced species experience niche shifts and whether niche shifts can be predicted. We found evidence of climatic niche shifts in 65-100% of 815 terrestrial plant species introduced across five continents, depending on how niche shifts were measured. Individual species responses were idiosyncratic, but we generally saw that niche shifts reflected changes in climate availability at the continent scale and were largest in long-lived and cultivated species. Smaller intercontinental niche shifts occurred within species' native ranges. Overall, the climatic niches of terrestrial plant species were not conserved as they crossed continents. These results have major consequences for applying environmental niche models to assess the risk of invasive species and for predicting species responses to climate change. Our findings challenge the tenet that species' niches are conserved aspects of their ecology.