Mechanical signaling cascades.

Mechanical computing has seen resurgent interest recently owing to the potential to embed sensing and computation into new classes of programmable metamaterials. To realize this, however, one must push signals from one part of a device to another and do so in a way that can be reset robustly. We investigate the propagation of signals in a bistable mechanical cascade uphill in energy. By identifying a penetration length for perturbations, we show that signals can propagate uphill for finite distances and map out parameters for this to occur. Experiments on soft elastomers corroborate our results.

Heterotrophic Bacteria Dominate Catalase Expression during Microcystis Blooms.

In the oligotrophic oceans, key autotrophs depend on "helper" bacteria to reduce oxidative stress from hydrogen peroxide (H2O2) in the extracellular environment. H2O2 is also a ubiquitous stressor in freshwaters, but the effects of H2O2 on autotrophs and their interactions with bacteria are less well understood in freshwaters. Naturally occurring H2O2 in freshwater systems is proposed to impact the proportion of microcystin-producing (toxic) and non-microcystin-producing (nontoxic) Microcystis in blooms, which influences toxin concentrations and human health impacts. However, how different strains of Microcystis respond to naturally occurring H2O2 concentrations and the microbes responsible for H2O2 decomposition in freshwater cyanobacterial blooms are unknown. To address these knowledge gaps, we used metagenomics and metatranscriptomics to track the presence and expression of genes for H2O2 decomposition by microbes during a cyanobacterial bloom in western Lake Erie in the summer of 2014. katG encodes the key enzyme for decomposing extracellular H2O2 but was absent in most Microcystis cells. katG transcript relative abundance was dominated by heterotrophic bacteria. In axenic Microcystis cultures, an H2O2 scavenger (pyruvate) significantly improved growth rates of one toxic strain while other toxic and nontoxic strains were unaffected. These results indicate that heterotrophic bacteria play a key role in H2O2 decomposition in Microcystis blooms and suggest that their activity may affect the fitness of some Microcystis strains and thus the strain composition of Microcystis blooms but not along a toxic versus nontoxic dichotomy. IMPORTANCE Cyanobacterial harmful algal blooms (CHABs) threaten freshwater ecosystems globally through the production of toxins. Toxin production by cyanobacterial species and strains during CHABs varies widely over time and space, but the ecological drivers of the succession of toxin-producing species remain unclear. Hydrogen peroxide (H2O2) is ubiquitous in natural waters, inhibits microbial growth, and may determine the relative proportions of Microcystis strains during blooms. However, the mechanisms and organismal interactions involved in H2O2 decomposition are unexplored in CHABs. This study shows that some strains of bloom-forming freshwater cyanobacteria benefit from detoxification of H2O2 by associated heterotrophic bacteria, which may impact bloom development.

What are the key features of orthorexia nervosa and influences on its development? A qualitative investigation.

Orthorexia nervosa (ON) - a pathological obsession with healthy eating - is an emerging eating disorder. The precise nature of ON and its causes remain unclear, yet few published research studies speak directly to those with ON tendencies or professionals working with them. Our study redresses this gap in the literature by uncovering the defining ON features and the factors influencing its development. The exploratory qualitative research design included semi-structured interviews with those self-identifying as orthorexic or obsessively preoccupied with healthy eating (n = 9), and professionals working with ON and eating disorders - psychologists, dieticians and a family therapist (n = 7). Data were analysed thematically. ON emerged as multifactorial, with a variety of interrelated influences needing to coalesce for 'healthy eating' to become pathological. Key features included rigidity and control (around food choices, routines and preparation) and moral judgements around food, along with a range of negative psychosocial and physical impacts. Influences on the development of ON were organised according to their occurrence at the individual (micro) level, external/relational (meso) level and societal (macro) level. Influences on the individual included health concerns, belief in food as medicine, past trauma, personality (e.g. obsessive, perfectionist), exposure to extreme views and behaviours while growing up and moral concerns. External influences included parents, partners and relational groups (e.g. fitness or clean eating groups). Societal influences included aestheticism, moral citizenship and social media. We conclude that ON is more than an individual pathology, it is symptomatic of our 'orthorexic society': where hyper-reflexivity around food choices, conflicting information regarding the correct diet, preoccupation with appearance, and emphasis on individual (not collective) responsibility for health combine with individual susceptibilities and ecological/moral concerns, to predispose toward pathological 'healthy' eating.

The Social Construction of a Concept-Orthorexia Nervosa: Morality Narratives and Psycho-Politics.

Our article explores orthorexia nervosa (ON)-an extreme fixation with healthy eating-from a social construction perspective. Interviews with people self-identified as "obsessed" with healthy eating or having ON ("Identifiers") and nonmedical professionals working with ON ("Professionals") were comparatively analyzed, along with orthorexia threads from an eating disorder website ("Posters"). Participants made sense of and rationalized their attitudes and feelings concerning healthy eating and aligned themselves according to their interests. Identifiers and Posters applauded "healthy eating" and regarded consumption of "impure" foods as leading to ill-health. Some framed their dietary discipline within an ethically motivated lifestyle, while others were preoccupied with appearance or weight management. Professionals expressed concern for, and disapproval of, extreme views and behaviors in clients and parental and social influences supporting them. Debates surrounding orthorexic practices are tangled; some individuals need help, yet dangers lie in over medicalizing or "troubling" what may be a preferred lifestyle.

"Another tool for the tool box? I'll take it!": Feasibility and acceptability of mobile recovery outreach teams (MROT) for opioid overdose patients in the emergency room.

Drug poisoning deaths involving opioids have increased exponentially in the United States. Post-overdose outreach to patients in the emergency room (ER) is a promising strategy for increasing uptake of medication assisted treatment and reducing subsequent overdose. We conducted a mixed methods study to investigate the feasibility and acceptability of a mobile recovery outreach team (MROT) program for opioid overdose patients presenting in Nevada's ERs, which was funded by the SAMHSA Opioid State Targeted Response (STR) grant. We interviewed 25 ER staff using quantitative questions informed by Diffusion of Innovation (DOI) theory and qualitative questions regarding their experiences caring for overdose patients, perceived benefits, and concerns about the MROT program. Respondents expressed strong support and enthusiasm for the program, identified advantages of the program relative to standard of care, highlighted logistical issues that must be addressed prior to implementation, and illustrated how the MROT program is compatible with their personal and professional values. Our results suggest that the STR-funded MROT program could reduce burden and stress among ER staff and improve patient outcomes, but must be informed by formative research that addresses issues of logistical complexity and cultural compatibility.

Correction: Verrucomicrobia are prevalent in north-temperate freshwater lakes and display class-level preferences between lake habitats.

[This corrects the article DOI: 10.1371/journal.pone.0195112.].

Verrucomicrobia are prevalent in north-temperate freshwater lakes and display class-level preferences between lake habitats.

The bacterial phylum Verrucomicrobia was formally described two decades ago and originally believed to be a minor member of many ecosystems; however, it is now recognized as ubiquitous and abundant in both soil and aquatic systems. Nevertheless, knowledge of the drivers of its relative abundance and within-phylum habitat preferences remains sparse, especially in lake systems. Here, we documented the distribution of Verrucomicrobia in 12 inland lakes in Southeastern Michigan, a Laurentian Great Lake (Lake Michigan), and a freshwater estuary, which span a gradient in lake sizes, depths, residence times, and trophic states. A wide range of physical and geochemical parameters was covered by sampling seasonally from the surface and bottom of each lake, and by separating samples into particle-associated and free-living fractions. On average, Verrucomicrobia was the 4th most abundant phylum (range 1.7-41.7%). Fraction, season, station, and depth explained up to 70% of the variance in Verrucomicrobia community composition and preference for these habitats was phylogenetically conserved at the class-level. When relative abundance was linearly modeled against environmental data, Verrucomicrobia and non-Verrucomicrobia bacterial community composition correlated to similar quantitative environmental parameters, although there were lake system-dependent differences and > 55% of the variance remained unexplained. A majority of the phylum exhibited preference for the particle-associated fraction and two classes (Opitutae and Verrucomicrobiae) were identified to be more abundant during the spring season. This study highlights the high relative abundance of Verrucomicrobia in north temperate lake systems and expands insights into drivers of within-phylum habitat preferences of the Verrucomicrobia.

Genome sequences of lower Great Lakes Microcystis sp. reveal strain-specific genes that are present and expressed in western Lake Erie blooms.

Blooms of the potentially toxic cyanobacterium Microcystis are increasing worldwide. In the Laurentian Great Lakes they pose major socioeconomic, ecological, and human health threats, particularly in western Lake Erie. However, the interpretation of "omics" data is constrained by the highly variable genome of Microcystis and the small number of reference genome sequences from strains isolated from the Great Lakes. To address this, we sequenced two Microcystis isolates from Lake Erie (Microcystis aeruginosa LE3 and M. wesenbergii LE013-01) and one from upstream Lake St. Clair (M. cf aeruginosa LSC13-02), and compared these data to the genomes of seventeen Microcystis spp. from across the globe as well as one metagenome and seven metatranscriptomes from a 2014 Lake Erie Microcystis bloom. For the publically available strains analyzed, the core genome is ~1900 genes, representing ~11% of total genes in the pan-genome and ~45% of each strain's genome. The flexible genome content was related to Microcystis subclades defined by phylogenetic analysis of both housekeeping genes and total core genes. To our knowledge this is the first evidence that the flexible genome is linked to the core genome of the Microcystis species complex. The majority of strain-specific genes were present and expressed in bloom communities in Lake Erie. Roughly 8% of these genes from the lower Great Lakes are involved in genome plasticity (rapid gain, loss, or rearrangement of genes) and resistance to foreign genetic elements (such as CRISPR-Cas systems). Intriguingly, strain-specific genes from Microcystis cultured from around the world were also present and expressed in the Lake Erie blooms, suggesting that the Microcystis pangenome is truly global. The presence and expression of flexible genes, including strain-specific genes, suggests that strain-level genomic diversity may be important in maintaining Microcystis abundance during bloom events.

Are Oligotypes Meaningful Ecological and Phylogenetic Units? A Case Study of Microcystis in Freshwater Lakes.

Oligotyping is a computational method used to increase the resolution of marker gene microbiome studies. Although oligotyping can distinguish highly similar sequence variants, the resulting units are not necessarily phylogenetically and ecologically informative due to limitations of the selected marker gene. In this perspective, we examine how oligotyping data is interpreted in recent literature, and we illustrate some of the method's constraints with a case study of the harmful bloom-forming cyanobacterium Microcystis. We identified three Microcystis oligotypes from a western Lake Erie bacterial community 16S rRNA gene (V4 region) survey that had previously clustered into one OTU. We found the same three oligotypes and two additional sequence variants in 46 Microcystis cultures isolated from Michigan inland lakes spanning a trophic gradient. In Lake Erie, shifts in Microcystis oligotypes corresponded to spatial nutrient gradients and temporal transitions in bloom toxicity. In the cultures, Microcystis oligotypes showed preferential distributions for different trophic states, but genomic data revealed that the oligotypes identified in Lake Erie did not correspond to toxin gene presence. Thus, oligotypes could not be used for inferring toxic ecotypes. Most strikingly, Microcystis oligotypes were not monophyletic. Our study supports the utility of oligotyping for distinguishing sequence types along certain ecological features, while it stresses that 16S rRNA gene sequence types may not reflect ecologically or phylogenetically cohesive populations. Therefore, we recommend that studies employing oligotyping or related tools consider these caveats during data interpretation.

Cyanobacterial harmful algal blooms are a biological disturbance to Western Lake Erie bacterial communities.

Human activities are causing a global proliferation of cyanobacterial harmful algal blooms (CHABs), yet we have limited understanding of how these events affect freshwater bacterial communities. Using weekly data from western Lake Erie in 2014, we investigated how the cyanobacterial community varied over space and time, and whether the bloom affected non-cyanobacterial (nc-bacterial) diversity and composition. Cyanobacterial community composition fluctuated dynamically during the bloom, but was dominated by Microcystis and Synechococcus OTUs. The bloom's progression revealed potential impacts to nc-bacterial diversity. Nc-bacterial evenness displayed linear, unimodal, or no response to algal pigment levels, depending on the taxonomic group. In addition, the bloom coincided with a large shift in nc-bacterial community composition. These shifts could be partitioned into components predicted by pH, chlorophyll a, temperature, and water mass movements. Actinobacteria OTUs showed particularly strong correlations to bloom dynamics. AcI-C OTUs became more abundant, while acI-A and acI-B OTUs declined during the bloom, providing evidence of niche partitioning at the sub-clade level. Thus, our observations in western Lake Erie support a link between CHABs and disturbances to bacterial community diversity and composition. Additionally, the short recovery of many taxa after the bloom indicates that bacterial communities may exhibit resilience to CHABs.

Seasonal Succession Leads to Habitat-Dependent Differentiation in Ribosomal RNA:DNA Ratios among Freshwater Lake Bacteria.

Relative abundance profiles of bacterial populations measured by sequencing DNA or RNA of marker genes can widely differ. These differences, made apparent when calculating ribosomal RNA:DNA ratios, have been interpreted as variable activities of bacterial populations. However, inconsistent correlations between ribosomal RNA:DNA ratios and metabolic activity or growth rates have led to a more conservative interpretation of this metric as the cellular protein synthesis potential (PSP). Little is known, particularly in freshwater systems, about how PSP varies for specific taxa across temporal and spatial environmental gradients and how conserved PSP is across bacterial phylogeny. Here, we generated 16S rRNA gene sequencing data using simultaneously extracted DNA and RNA from fractionated (free-living and particulate) water samples taken seasonally along a eutrophic freshwater estuary to oligotrophic pelagic transect in Lake Michigan. In contrast to previous reports, we observed frequent clustering of DNA and RNA data from the same sample. Analysis of the overlap in taxa detected at the RNA and DNA level indicated that microbial dormancy may be more common in the estuary, the particulate fraction, and during the stratified period. Across spatiotemporal gradients, PSP was often conserved at the phylum and class levels. PSPs for specific taxa were more similar across habitats in spring than in summer and fall. This was most notable for PSPs of the same taxa when located in the free-living or particulate fractions, but also when contrasting surface to deep, and estuary to Lake Michigan communities. Our results show that community composition assessed by RNA and DNA measurements are more similar than previously assumed in freshwater systems. However, the similarity between RNA and DNA measurements and taxa-specific PSPs that drive community-level similarities are conditional on spatiotemporal factors.

Community readiness for a computer-based health information network.

The need for timely and accurate communication among healthcare providers has prompted the development of computer-based health information networks that allow patient and client information to be shared among agencies. This article reports the findings of a study to assess whether residents of an upstate New York community were ready for a computer-based health information network to facilitate delivery of long term care services. Focus group sessions, which involved both consumers and professionals, revealed that security of personal information was of concern to healthcare providers, attorneys, and consumers. Physicians were the most enthusiastic about the possibility of a computer-based health information network. Consumers and other healthcare professionals, including nurses, indicated that such a network would be helpful to them personally. Nurses and other healthcare professionals need to be knowledgeable about the use of computer-based health information networks and other electronic information systems as this trend continues to spread across the U.S.

Cerebellar abiotrophy in a miniature schnauzer.

A 3.5-month-old miniature schnauzer was presented for signs of progressive cerebellar ataxia. Necropsy revealed cerebellar abiotrophy. This is the first reported case of cerebellar abiotrophy in a purebred miniature schnauzer.