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1.
Ecol Evol ; 14(6): e11483, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38826168

ABSTRACT

The anther-smut host-pathogen system has provided extensive insights into the evolutionary ecology of disease resistance, transmission modes, host shifts, pathogen specialization, and disease evolution in metapopulations. It also has led to unexpected insights into sex ratio distorters, sex chromosome evolution, and transposable elements in fungi. In addition, anther-smut disease played a major role in Linnaeus' germ theory and the correspondence on parasitic castration between Darwin and Becker, one of the first female botanists. Here, we explicitly highlight some of the realities in the process of science, using an unusual autobiographical approach to describe how we came to collaborate on this system in the 1980s. Using perspectives from our different career stages, we present a surprising narrative that could not be deduced from merely reading the published papers. While our work was grounded in previous ecological and evolutionary theory, it was the product as much of empirical failures and intellectual roadblocks, as the result of a progressive scientific method. Our experiences illustrate not only the "human dimension of science" but more importantly show that linear sequences of hypothesis testing do not necessarily lead to new study systems and new ideas. We suggest there is a need to re-evaluate the scientific method in ecology and evolution, especially where the challenge is to engage in a productive dialog between natural history and theory.

2.
PLoS Comput Biol ; 20(5): e1012146, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38805543

ABSTRACT

Exposure to environmental stressors, including certain antibiotics, induces stress responses in bacteria. Some of these responses increase mutagenesis and thus potentially accelerate resistance evolution. Many studies report increased mutation rates under stress, often using the standard experimental approach of fluctuation assays. However, single-cell studies have revealed that many stress responses are heterogeneously expressed in bacterial populations, which existing estimation methods have not yet addressed. We develop a population dynamic model that considers heterogeneous stress responses (subpopulations of cells with the response off or on) that impact both mutation rate and cell division rate, inspired by the DNA-damage response in Escherichia coli (SOS response). We derive the mutant count distribution arising in fluctuation assays under this model and then implement maximum likelihood estimation of the mutation-rate increase specifically associated with the expression of the stress response. Using simulated mutant count data, we show that our inference method allows for accurate and precise estimation of the mutation-rate increase, provided that this increase is sufficiently large and the induction of the response also reduces the division rate. Moreover, we find that in many cases, either heterogeneity in stress responses or mutant fitness costs could explain similar patterns in fluctuation assay data, suggesting that separate experiments would be required to identify the true underlying process. In cases where stress responses and mutation rates are heterogeneous, current methods still correctly infer the effective increase in population mean mutation rate, but we provide a novel method to infer distinct stress-induced mutation rates, which could be important for parameterising evolutionary models.

4.
Microbiology (Reading) ; 169(8)2023 08.
Article in English | MEDLINE | ID: mdl-37561015

ABSTRACT

Studies of microbial evolution, especially in applied contexts, have focused on the role of selection in shaping predictable, adaptive responses to the environment. However, chance events - the appearance of novel genetic variants and their establishment, i.e. outgrowth from a single cell to a sizeable population - also play critical initiating roles in adaptation. Stochasticity in establishment has received little attention in microbiology, potentially due to lack of awareness as well as practical challenges in quantification. However, methods for high-replicate culturing, mutant labelling and detection, and statistical inference now make it feasible to experimentally quantify the establishment probability of specific adaptive genotypes. I review methods that have emerged over the past decade, including experimental design and mathematical formulas to estimate establishment probability from data. Quantifying establishment in further biological settings and comparing empirical estimates to theoretical predictions represent exciting future directions. More broadly, recognition that adaptive genotypes may be stochastically lost while rare is significant both for interpreting common lab assays and for designing interventions to promote or inhibit microbial evolution.


Subject(s)
Biological Evolution , Mutation
5.
Clin Exp Allergy ; 53(5): 495-510, 2023 05.
Article in English | MEDLINE | ID: mdl-36949024

ABSTRACT

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin condition with an unpredictable clinical course, associated with a significant impact on quality of life. The pathophysiology of AD involves a complex interplay between impaired skin barrier function, immune dysregulation, genetic susceptibility and environmental factors. Advances in understanding of the immunological mechanisms that underpin AD have heralded the recognition of multiple novel therapeutic targets to bolster the systemic treatment armamentarium for patients with severe AD. This review examines current and future directions of non-biologic systemic treatments for AD, with a focus on their mechanism of action, efficacy and safety, and the key considerations to help inform treatment decisions. We summarize new developments in small molecule systemic therapies which have the potential to further advance our management of AD in this new era of precision medicine.


Subject(s)
Dermatitis, Atopic , Humans , Quality of Life , Administration, Cutaneous , Precision Medicine
7.
J Dermatol Sci ; 106(3): 132-140, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35537882

ABSTRACT

BACKGROUND: Loss-of-function mutations in the filaggrin (FLG) gene directly alter skin barrier function and critically influence atopic inflammation. While skin barrier dysfunction, Th2-associated inflammation and bacterial dysbiosis are well-known characteristics of atopic dermatitis (AD), the mechanisms interconnecting genotype, transcriptome and microbiome remain largely elusive. OBJECTIVE: In-depth analysis of FLG genotype-associated skin gene expression alterations and host-microbe interactions in AD. METHODS: Multi-omics characterization of a cohort of AD patients carrying heterozygous loss-of-function mutations in the FLG gene (ADMut) (n = 15), along with matched wild-type (ADWt) patients and healthy controls. Detailed clinical characterization, microarray gene expression and 16 S rRNA-based microbial marker gene data were generated and analyzed. RESULTS: In the context of filaggrin dysfunction, the transcriptome was characterized by dysregulation of barrier function and water homeostasis, while the lesional skin of ADWt demonstrated the specific upregulation of pro-inflammatory cytokines and T-cell proliferation. S. aureus dominated the microbiome in both patient groups, however, shifting microbial communities could be observed when comparing healthy with non-lesional ADWt or ADMut skin, offering the opportunity to identify microbe-associated transcriptomic signatures. Moreover, an AD core signature with 28 genes, including CCL13, CCL18, BTC, SCIN, RAB31 and PCLO was identified. CONCLUSIONS: Our integrative approach provides molecular insights for the concept that FLG loss-of-function mutations are a genetic shortcut to atopic inflammation and unravels the complex interplay between genotype, transcriptome and microbiome in the human holobiont.


Subject(s)
Dermatitis, Atopic , Filaggrin Proteins/metabolism , Dermatitis, Atopic/metabolism , Host Microbial Interactions/genetics , Humans , Inflammation/genetics , Inflammation/metabolism , Intermediate Filament Proteins/genetics , Intermediate Filament Proteins/metabolism , Mutation , Skin/metabolism , Staphylococcus aureus
8.
J Allergy Clin Immunol ; 150(3): 709-713, 2022 09.
Article in English | MEDLINE | ID: mdl-35469843

ABSTRACT

BACKGROUND: Atopic dermatitis (AD) is associated with immune dysregulation, but epidemiologic data on the pattern of autoimmune comorbidity in people with AD are limited. OBJECTIVE: We sought to determine the risk of autoimmune conditions in people newly diagnosed with AD. METHODS: Retrospective cohort analysis (January 2009 to December 2018), using the UK-based Oxford-Royal College of General Practitioners Research and Surveillance Centre primary care database. We compared baseline prevalence and incidence after diagnosis of autoimmune conditions in 173,709 children and adults with new-onset AD and 694,836 age-, sex-, and general practitioner practice-matched controls. Outcomes were a composite of any autoimmune condition (Crohn disease, ulcerative colitis, celiac disease, pernicious anemia, type 1 diabetes, autoimmune hypothyroidism, Graves disease, psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, Sjögren syndrome, vitiligo, alopecia areata, and multiple sclerosis) and each individual autoimmune condition. RESULTS: Preexisting autoimmune conditions were more common in people diagnosed with AD compared to controls (composite 5.8% vs 4.3%). Excluding people with preexisting autoimmune disease, there was an association between AD and incidence of new-onset autoimmune disease (composite adjusted hazard ratio [aHR] 1.28; 95% confidence interval [CI] 1.23-1.34). Risk was highest for more severe AD (aHR 1.99; 95% CI 1.77-2.23) than moderate AD (aHR 1.33; 95% CI 1.19-1.49) or mild AD (aHR 1.22; 95% CI 1.16-1.28). People with AD were at significantly increased risk of developing psoriatic arthritis, Sjögren syndrome, Crohn disease, vitiligo, alopecia areata, pernicious anemia, ulcerative colitis, rheumatoid arthritis, and hypothyroidism (aHR range 1.17-2.06), but not other autoimmune conditions. CONCLUSION: People with AD have an increased risk of multiple autoimmune conditions, especially those with more severe AD.


Subject(s)
Alopecia Areata , Anemia, Pernicious , Autoimmune Diseases , Colitis, Ulcerative , Crohn Disease , Dermatitis, Atopic , Hypothyroidism , Sjogren's Syndrome , Vitiligo , Adult , Alopecia Areata/epidemiology , Anemia, Pernicious/complications , Autoimmune Diseases/epidemiology , Autoimmune Diseases/etiology , Child , Cohort Studies , Colitis, Ulcerative/epidemiology , Crohn Disease/epidemiology , Dermatitis, Atopic/complications , Dermatitis, Atopic/epidemiology , Humans , Hypothyroidism/complications , Retrospective Studies
9.
Exp Dermatol ; 30(10): 1517-1531, 2021 10.
Article in English | MEDLINE | ID: mdl-34387406

ABSTRACT

The two most common chronic inflammatory skin diseases are atopic dermatitis (AD) and psoriasis. The underpinnings of the remarkable degree of clinical heterogeneity of AD and psoriasis are poorly understood and, as a consequence, disease onset and progression are unpredictable and the optimal type and time point for intervention are as yet unknown. The BIOMAP project is the first IMI (Innovative Medicines Initiative) project dedicated to investigating the causes and mechanisms of AD and psoriasis and to identify potential biomarkers responsible for the variation in disease outcome. The consortium includes 7 large pharmaceutical companies and 25 non-industry partners including academia. Since there is mounting evidence supporting an important role for microbial exposures and our microbiota as factors mediating immune polarization and AD and psoriasis pathogenesis, an entire work package is dedicated to the investigation of skin and gut microbiome linked to AD or psoriasis. The large collaborative BIOMAP project will enable the integration of patient cohorts, data and knowledge in unprecedented proportions. The project has a unique opportunity with a potential to bridge and fill the gaps between current problems and solutions. This review highlights the power and potential of the BIOMAP project in the investigation of microbe-host interplay in AD and psoriasis.


Subject(s)
Dermatitis, Atopic/immunology , Dermatitis, Atopic/microbiology , Microbiota/immunology , Psoriasis/immunology , Psoriasis/microbiology , Skin/immunology , Skin/microbiology , Humans
10.
JMIR Form Res ; 5(9): e20131, 2021 Sep 27.
Article in English | MEDLINE | ID: mdl-34449404

ABSTRACT

BACKGROUND: Most people with COVID-19 self-manage at home. However, the condition can deteriorate quickly, and some people may develop serious hypoxia with relatively few symptoms. Early identification of deterioration allows effective management with oxygen and steroids. Telemonitoring of symptoms and physiological signs may facilitate this. OBJECTIVE: The aim of this study was to design, implement, and evaluate a telemonitoring system for people with COVID-19 who are self-managing at home and are considered at significant risk of deterioration. METHODS: A multidisciplinary team developed a telemonitoring protocol using a commercial platform to record symptoms, pulse oximetry, and temperature. If symptoms or physiological measures breached targets, patients were alerted and asked to phone for an ambulance (red alert) or for advice (amber alert). Patients attending COVID-19 assessment centers, who were considered fit for discharge but at risk of deterioration, were shown how to use a pulse oximeter and the monitoring system, which they were to use twice daily for 2 weeks. Patients could interact with the system via app, SMS, or touch-tone phone. Written guidance on alerts was also provided. Following consent, patient data on telemonitoring usage and alerts were linked to data on the use of service resources. Subsequently, patients who had either used or not used the telemonitoring service, including those who had not followed advice to seek help, agreed to brief telephone interviews to explore their views on, and how they had interacted with, the telemonitoring system. Interviews were recorded and analyzed thematically. Professionals involved in the implementation were sent an online questionnaire asking them about their perceptions of the service. RESULTS: We investigated the first 116 patients who used the service. Of these patients, 71 (61.2%) submitted data and the remainder (n=45, 38.8%) chose to self-monitor without electronic support. Of the 71 patients who submitted data, 35 (49%) received 152 alerts during their 2-week observation. A total of 67 red alerts were for oxygen saturation (SpO2) levels of ≤93%, and 15 red alerts were because patients recorded severe breathlessness. Out of 71 patients, 14 (20%) were admitted to hospital for an average stay of 3.6 (SD 4.5) days. Of the 45 who used written guidance alone, 7 (16%) were admitted to hospital for an average stay of 4.0 (SD 4.2) days and 1 (2%) died. Some patients who were advised to seek help did not do so, some because parameters improved on retesting and others because they felt no worse than before. All patients found self-monitoring to be reassuring. Of the 11 professionals who used the system, most found it to be useful and easy to use. Of these 11 professionals, 5 (45%) considered the system "very safe," 3 (27%) thought it "could be safer," and 3 (27%) wished to have more experience with it before deciding. In total, 2 (18%) felt that SpO2 trigger thresholds were too high. CONCLUSIONS: Supported self-monitoring of patients with COVID-19 at home is reassuring to patients, is acceptable to clinicians, and can detect important signs of deterioration. Worryingly, some patients, because they felt well, occasionally ignored important signs of deterioration. It is important, therefore, to emphasize the importance of the early investigation and treatment of asymptomatic hypoxia at the time when patients are initiated and in the warning messages that are sent to patients.

11.
Clin Exp Allergy ; 51(3): 430-451, 2021 03.
Article in English | MEDLINE | ID: mdl-33259122

ABSTRACT

BACKGROUND: Hard domestic water has been reported to worsen atopic eczema (AE) and may contribute to its development in early life. OBJECTIVE: To review the literature on the relationship between the effect of water hardness (high calcium carbonate; CaCO3 ) on (a) the risk of developing AE, (b) the treatment of existing AE and (c) skin barrier function in human and animal studies. DESIGN , DATA SOURCES AND ELIGIBILITY CRITERIA: We systematically searched databases (MEDLINE, Embase, Cochrane CENTRAL, GREAT and Web of Science) from inception until 30/6/2020. Human and animal observational and experimental studies were included. The primary outcomes were risk of AE and skin barrier function. Studies were meta-analysed using a random effects model. Evidence certainty was evaluated using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RESULTS: Sixteen studies were included. Pooled observational data from seven studies on 385,901 participants identified increased odds of AE in children exposed to harder versus softer water (odds ratio 1.28, 95% CI 1.09, 1.50; GRADE certainty: very low). Two mechanistic studies in humans reported higher deposition of the detergent sodium lauryl sulphate in those exposed to harder versus softer water. Two randomized controlled trials comparing water softeners with standard care did not show a significant difference in objective AE severity with softened water (standardized mean difference 0.06 standard deviations higher, 95% CI 0.16 lower to 0.27 higher; GRADE certainty: moderate). CONCLUSIONS & CLINICAL RELEVANCE: There was a positive association between living in a hard water (range: 76 to > 350 mg/L CaCO3 ) area and AE in children. There is no evidence that domestic water softeners improve objective disease severity in established AE. There may be a role of water hardness in the initiation of skin inflammation in early life, but there is a need for further longitudinal and interventional studies.


Subject(s)
Calcium Carbonate , Dermatitis, Atopic/epidemiology , Skin/chemistry , Water/chemistry , Animals , Dermatitis, Atopic/physiopathology , Detergents , Humans , Severity of Illness Index , Skin/physiopathology , Sodium Dodecyl Sulfate , Surface-Active Agents , Water Softening
12.
Allergy ; 76(4): 1173-1187, 2021 04.
Article in English | MEDLINE | ID: mdl-33001460

ABSTRACT

It is well established that different sites in healthy human skin are colonized by distinct microbial communities due to different physiological conditions. However, few studies have explored microbial heterogeneity between skin sites in diseased skin, such as atopic dermatitis (AD) lesions. To address this issue, we carried out deep analysis of the microbiome and transcriptome in the skin of a large cohort of AD patients and healthy volunteers, comparing two physiologically different sites: upper back and posterior thigh. Microbiome samples and biopsies were obtained from both lesional and nonlesional skin to identify changes related to the disease process. Transcriptome analysis revealed distinct disease-related gene expression profiles depending on anatomical location, with keratinization dominating the transcriptomic signatures in posterior thigh, and lipid metabolism in the upper back. Moreover, we show that relative abundance of Staphylococcus aureus is associated with disease severity in the posterior thigh, but not in the upper back. Our results suggest that AD may select for similar microbes in different anatomical locations-an "AD-like microbiome," but distinct microbial dynamics can still be observed when comparing posterior thigh to upper back. This study highlights the importance of considering the variability across skin sites when studying the development of skin inflammation.


Subject(s)
Dermatitis, Atopic , Eczema , Microbiota , Dermatitis, Atopic/genetics , Humans , Skin , Staphylococcus aureus/genetics
13.
Clin Exp Allergy ; 51(3): 471-482, 2021 03.
Article in English | MEDLINE | ID: mdl-33179341

ABSTRACT

BACKGROUND: Whilst eczema is a common inflammatory skin condition, we lack contemporary estimates of disease incidence and prevalence across the lifespan. OBJECTIVE: To estimate the incidence and prevalence of eczema in children and adults in England and variation by sociodemographic factors (sex, socio-economic status, ethnicity, and geography). METHODS: We used the Royal College of General Practitioners Research and Surveillance Centre primary care research database of 3.85 million children and adults registered with participating general practitioner practices between 2009 and 2018 inclusive. Eczema incidence was defined as the first-ever diagnosis of eczema recorded in the primary care record, and eczema prevalence was defined as fulfilment of criteria for active eczema (two eczema records appearing in the primary care record within any one-year period). RESULTS: Eczema incidence was highest in infants younger than 1 year (15.0 per 100 person-years), lowest in adults aged 40-49 (0.35 p/100 person-years), and increased from middle age to a second smaller peak in people 80 years or older (0.79 p/100 person-years). Eczema prevalence was highest in children aged 2 (16.5%) and lowest in adults aged 30-39 (2.8%). Eczema incidence was higher in male infants (<2) and male adults older than 70; for all other ages, incidence was higher in females. Eczema was more common in Asian and black ethnic groups than in people of white ethnicity. Higher socio-economic status was associated with a greater incidence of eczema in infants younger than 2, but the reverse was seen for all other age groups. Both incidence and prevalence of eczema were greater in urban settings and in North-West England. CONCLUSIONS AND CLINICAL RELEVANCE: Eczema has a bimodal distribution across the lifespan. We observed differences in incidence and prevalence of eczema by ethnicity, geography, sex, and socio-economic status, which varied in magnitude throughout life.


Subject(s)
Dermatitis, Atopic/epidemiology , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Child , Child, Preschool , England/epidemiology , Female , Humans , Incidence , Infant , Infant, Newborn , Male , Middle Aged , Prevalence , Primary Health Care , Young Adult
14.
Clin Exp Allergy ; 51(3): 483-494, 2021 03.
Article in English | MEDLINE | ID: mdl-33176023

ABSTRACT

BACKGROUND: Despite the high disease burden of eczema, a contemporary overview of the patterns and trends in primary care healthcare utilization and treatment is lacking. OBJECTIVE: To quantify primary care consultations, specialist referrals, prescribing, and treatment escalation, in children and adults with eczema in England. METHODS: A large primary care research database was used to examine healthcare and treatment utilization in people with active eczema (n = 411,931). Management trends and variations by age, sex, socioeconomic status, and ethnicity were described from 2009 to 2018 inclusive. RESULTS: Primary care consultation rates increased from 87.8 (95% confidence interval [95% CI] 87.3-88.3) to 112.0 (95% CI 111.5-112.6) per 100 person-years over 2009 to 2018. Specialist referral rates also increased from 3.8 (95% CI 3.7-3.9) to 5.0 (95% CI 4.9-5.1) per 100 person-years over the same period. Consultation rates were highest in infants. Specialist referrals were greatest in the over 50s and lowest in people of lower socioeconomic status, despite a higher rate of primary care consultations. There were small changes in prescribing over time; emollients increased (prescribed to 48.5% of people with active eczema in 2009 compared to 51.4% in 2018) and topical corticosteroids decreased (57.3%-52.0%). Prescribing disparities were observed, including less prescribing of potent and very potent topical corticosteroids in non-white ethnicities and people of lower socioeconomic status. Treatment escalation was more common with increasing age and in children of non-white ethnicity. CONCLUSION AND CLINICAL RELEVANCE: The management of eczema varies by sociodemographic status in England, with lower rates of specialist referral in people from more-deprived backgrounds. There are different patterns of healthcare utilization, treatment, and treatment escalation in people of non-white ethnicity and of more-deprived backgrounds.


Subject(s)
Dermatitis, Atopic/therapy , Healthcare Disparities/ethnology , Practice Patterns, Physicians'/statistics & numerical data , Referral and Consultation/statistics & numerical data , Social Class , Administration, Cutaneous , Administration, Oral , Adolescent , Adult , Age Factors , Anti-Infective Agents/therapeutic use , Child , Child, Preschool , Emollients/therapeutic use , Ethnicity , Female , Glucocorticoids/therapeutic use , Healthcare Disparities/statistics & numerical data , Histamine Antagonists/therapeutic use , Humans , Immunomodulating Agents/therapeutic use , Infant , Male , Middle Aged , Primary Health Care , United Kingdom , Young Adult
15.
BMJ Open ; 10(9): e037518, 2020 09 16.
Article in English | MEDLINE | ID: mdl-32938595

ABSTRACT

INTRODUCTION: Atopic dermatitis (AD) is one of the most common inflammatory skin conditions in both children and adults. Despite this, contemporary descriptions of the incidence, prevalence and current management of the condition in the UK are lacking. METHODS AND ANALYSIS: We will perform a series of retrospective studies using a large population-based cohort derived from the Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) network database to explore two key research themes: AD epidemiology and AD management.In the epidemiology theme, we will describe the incidence and prevalence of AD in children and adults in England from 2009 to 2018 inclusive. We will stratify findings by age, national Index of Multiple Deprivation (IMD), ethnicity, urban-rural environment and geographic location; and explore independent associations of these features with AD in multivariable models.In the management theme, we will explore healthcare utilisation and treatment in people with AD. Regarding healthcare utilisation, we will evaluate rates of AD-associated primary care visits and specialist dermatology referrals in people with AD. Rates will be stratified by age, gender, socioeconomic IMD quintile and ethnicity. We will describe contemporary treatment by estimating prescribing rates across medication classes used in AD (emollients, topical corticosteroids by potency, topical calcineurin inhibitors, topical antimicrobials, antihistamines, oral corticosteroids and systemic immunomodulatory therapies) overall, and by age and sociodemographic groupings. We will also examine trends in prescribing over the study period. In people first diagnosed with AD during the study period, we will describe differences in treatment escalation by sociodemographic factors using time-to-event analysis. ETHICS AND DISSEMINATION: The Health Research Authority decision tool classed this a study of 'usual practice', ethics approval was not required. Study approval was granted by the RCGP RSC Study Approval Committee. Results will be disseminated through peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT03823794.


Subject(s)
Dermatitis, Atopic , Adult , Child , Cohort Studies , Dermatitis, Atopic/drug therapy , Dermatitis, Atopic/epidemiology , Emollients/therapeutic use , England/epidemiology , Humans , Observational Studies as Topic , Retrospective Studies
16.
Ecol Evol ; 10(13): 6208-6222, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32724508

ABSTRACT

Both mutualistic and pathogenic soil microbes are known to play important roles in shaping the fitness of plants, likely affecting plants at different life cycle stages.In order to investigate the differential effects of native soil mutualists and pathogens on plant fitness, we compared survival and reproduction of two annual tallgrass prairie plant species (Chamaecrista fasciculata and Coreopsis tinctoria) in a field study using 3 soil inocula treatments containing different compositions of microbes. The soil inocula types included fresh native whole soil taken from a remnant prairie containing both native mutualists and pathogens, soil enhanced with arbuscular mycorrhizal (AM) fungi derived from remnant prairies, and uninoculated controls.For both species, plants inoculated with native prairie AM fungi performed much better than those in uninoculated soil for all parts of the life cycle. Plants in the native whole prairie soil were either generally similar to plants in the uninoculated soil or had slightly higher survival or reproduction.Overall, these results suggest that native prairie AM fungi can have important positive effects on the fitness of early successional plants. As inclusion of prairie AM fungi and pathogens decreased plant fitness relative to prairie AM fungi alone, we expect that native pathogens also can have large effects on fitness of these annuals. Our findings support the use of AM fungi to enhance plant establishment in prairie restorations.

17.
Proc Natl Acad Sci U S A ; 117(32): 19455-19464, 2020 08 11.
Article in English | MEDLINE | ID: mdl-32703812

ABSTRACT

A better understanding of how antibiotic exposure impacts the evolution of resistance in bacterial populations is crucial for designing more sustainable treatment strategies. The conventional approach to this question is to measure the range of concentrations over which resistant strain(s) are selectively favored over a sensitive strain. Here, we instead investigate how antibiotic concentration impacts the initial establishment of resistance from single cells, mimicking the clonal expansion of a resistant lineage following mutation or horizontal gene transfer. Using two Pseudomonas aeruginosa strains carrying resistance plasmids, we show that single resistant cells have <5% probability of detectable outgrowth at antibiotic concentrations as low as one-eighth of the resistant strain's minimum inhibitory concentration (MIC). This low probability of establishment is due to detrimental effects of antibiotics on resistant cells, coupled with the inherently stochastic nature of cell division and death on the single-cell level, which leads to loss of many nascent resistant lineages. Our findings suggest that moderate doses of antibiotics, well below the MIC of resistant strains, may effectively restrict de novo emergence of resistance even though they cannot clear already-large resistant populations.


Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/drug effects , Pseudomonas aeruginosa/drug effects , Dose-Response Relationship, Drug , Drug Resistance, Bacterial/genetics , Microbial Sensitivity Tests , Microbial Viability/drug effects , Models, Theoretical , Plasmids/genetics , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/growth & development , Single-Cell Analysis , Stochastic Processes
18.
Evol Med Public Health ; 2020(1): 30-34, 2020.
Article in English | MEDLINE | ID: mdl-32099654

ABSTRACT

Lay Summary: Competition often occurs among diverse parasites within a single host, but control efforts could change its strength. We examined how the interplay between competition and control could shape the evolution of parasite traits like drug resistance and disease severity.

19.
Nat Commun ; 10(1): 4703, 2019 10 16.
Article in English | MEDLINE | ID: mdl-31619666

ABSTRACT

Despite recent advances in understanding microbial diversity in skin homeostasis, the relevance of microbial dysbiosis in inflammatory disease is poorly understood. Here we perform a comparative analysis of skin microbial communities coupled to global patterns of cutaneous gene expression in patients with atopic dermatitis or psoriasis. The skin microbiota is analysed by 16S amplicon or whole genome sequencing and the skin transcriptome by microarrays, followed by integration of the data layers. We find that atopic dermatitis and psoriasis can be classified by distinct microbes, which differ from healthy volunteers microbiome composition. Atopic dermatitis is dominated by a single microbe (Staphylococcus aureus), and associated with a disease relevant host transcriptomic signature enriched for skin barrier function, tryptophan metabolism and immune activation. In contrast, psoriasis is characterized by co-occurring communities of microbes with weak associations with disease related gene expression. Our work provides a basis for biomarker discovery and targeted therapies in skin dysbiosis.


Subject(s)
Dermatitis, Atopic/genetics , Host Microbial Interactions/genetics , Microbiota/genetics , Psoriasis/genetics , Skin/metabolism , Skin/microbiology , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Dermatitis, Atopic/microbiology , Dysbiosis/genetics , Female , Gene Expression , Gene Expression Profiling , Humans , Male , Middle Aged , Psoriasis/microbiology , RNA, Ribosomal, 16S , Young Adult
20.
Health Expect ; 22(6): 1260-1271, 2019 12.
Article in English | MEDLINE | ID: mdl-31486184

ABSTRACT

BACKGROUND: Non-attendance at diabetes appointments is costly to the health service and linked with poorer patient outcomes. OBJECTIVE: Peer researchers aimed to conduct interviews and survey people who miss appointments about their beliefs and perceptions regarding their diabetes and diabetes appointments. DESIGN: A mixed-methods cross-sectional design with interviews conducted by peer researchers with diabetes and a questionnaire was used. SETTING AND PARTICIPANTS: Peer researchers conducted semi-structured telephone interviews in one health board in Scotland with ten people who had missed diabetes appointments. A further 34 people who had missed appointments completed a questionnaire. The study was informed by two psychological theories (the Theory of Planned Behaviour and the Self-Regulation Model), and interviews were analysed using thematic analysis. RESULTS: Interviewees planned to attend appointments but practical barriers, low perceived value of appointments and the feeling that diabetes had little impact upon their lives' emerged as key reasons for missing appointments. Questionnaire data supported these findings and showed that respondents perceived diabetes to have only mildly serious consequence and cause limited concern and emotional impact. Participants' understanding of their condition and perceptions of personal control and treatment control were low. Gender, perceived behavioural control and emotional representations were significantly associated with the number of appointments missed in the previous year. CONCLUSIONS: These findings highlight the importance of psychological variables in predicting non-attendance at diabetes appointments and provide avenues for how non-attendance might be tackled.


Subject(s)
Diabetes Mellitus/therapy , No-Show Patients/psychology , Research Personnel/psychology , Attitude to Health , Cross-Sectional Studies , Diabetes Mellitus/psychology , Diabetes Mellitus, Type 1/psychology , Diabetes Mellitus, Type 1/therapy , Diabetes Mellitus, Type 2/psychology , Diabetes Mellitus, Type 2/therapy , Female , Health Services Accessibility , Humans , Interviews as Topic , Male , Middle Aged , Patient Participation , Peer Group , Surveys and Questionnaires
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