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1.
Nature ; 605(7910): 527-531, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35545676

RESUMO

Gasdermins (GSDMs) are a family of pore-forming effectors that permeabilize the cell membrane during the cell death program pyroptosis1. GSDMs are activated by proteolytic removal of autoinhibitory carboxy-terminal domains, typically by caspase regulators1-9. However, no activator is known for one member of this family, GSDMA. Here we show that the major human pathogen group A Streptococcus (GAS) secretes a protease virulence factor, SpeB, that induces GSDMA-dependent pyroptosis. SpeB cleavage of GSDMA releases an active amino-terminal fragment that can insert into membranes to form lytic pores. GSDMA is primarily expressed in the skin10, and keratinocytes infected with SpeB-expressing GAS die of GSDMA-dependent pyroptosis. Mice have three homologues of human GSDMA, and triple-knockout mice are more susceptible to invasive infection by a pandemic hypervirulent M1T1 clone of GAS. These results indicate that GSDMA is critical in the immune defence against invasive skin infections by GAS. Furthermore, they show that GSDMs can act independently of host regulators as direct sensors of exogenous proteases. As SpeB is essential for tissue invasion and survival within skin cells, these results suggest that GSDMA can act akin to a guard protein that directly detects concerning virulence activities of microorganisms that present a severe infectious threat.


Assuntos
Piroptose , Streptococcus pyogenes , Animais , Caspases , Queratinócitos , Camundongos , Proteínas Citotóxicas Formadoras de Poros , Streptococcus pyogenes/metabolismo , Streptococcus pyogenes/patogenicidade , Virulência , Fatores de Virulência
2.
PLoS Pathog ; 19(4): e1011321, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37068092

RESUMO

Group A Streptococcus (GAS, Streptococcus pyogenes) is a professional human pathogen that commonly infects the skin. Keratinocytes are one of the first cells to contact GAS, and by inducing inflammation, they can initiate the earliest immune responses to pathogen invasion. Here, we characterized the proinflammatory cytokine repertoire produced by primary human keratinocytes and surrogate cell lines commonly used in vitro. Infection induces several cytokines and chemokines, but keratinocytes constitutively secrete IL-18 in a form that is inert (pro-IL-18) and lacks proinflammatory activity. Canonically, IL-18 activation and secretion are coupled through a single proteolytic event that is regulated intracellularly by the inflammasome protease caspase-1 in myeloid cells. The pool of extracellular pro-IL-18 generated by keratinocytes is poised to sense extracellular proteases. It is directly processed into a mature active form by SpeB, a secreted GAS protease that is a critical virulent factor during skin infection. This mechanism contributes to the proinflammatory response against GAS, resulting in T cell activation and the secretion of IFN-γ. Under these conditions, isolates of several other major bacterial pathogens and microbiota of the skin were found to not have significant IL-18-maturing ability. These results suggest keratinocyte-secreted IL-18 is a sentinel that sounds an early alarm that is highly sensitive to GAS, yet tolerant to non-invasive members of the microbiota.


Assuntos
Infecções Bacterianas , Interleucina-18 , Humanos , Infecções Bacterianas/metabolismo , Citocinas/metabolismo , Inflamação , Interleucina-18/metabolismo , Queratinócitos/metabolismo , Peptídeo Hidrolases/metabolismo
3.
Clin Infect Dis ; 78(Suppl 1): S38-S46, 2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38294118

RESUMO

BACKGROUND: Fluoroquinolones lack approval for treatment of tularemia but have been used extensively for milder illness. Here, we evaluated fluoroquinolones for severe illness. METHODS: In an observational study, we identified case-patients with respiratory tularemia from July to November 2010 in Jämtland County, Sweden. We defined severe tularemia by hospitalization for >24 hours and severe bacteremic tularemia by Francisella tularensis subsp. holarctica growth in blood or pleural fluid. Clinical data and drug dosing were retrieved from electronic medical records. Chest images were reexamined. We used Kaplan-Meier curves to evaluate time to defervescence and hospital discharge. RESULTS: Among 67 case-patients (median age, 66 years; 81% males) 30-day mortality was 1.5% (1 of 67). Among 33 hospitalized persons (median age, 71 years; 82% males), 23 had nonbacteremic and 10 had bacteremic severe tularemia. Subpleural round consolidations, mediastinal lymphadenopathy, and unilateral pleural fluid were common on chest computed tomography. Among 29 hospitalized persons with complete outcome data, ciprofloxacin/levofloxacin (n = 12), ciprofloxacin/levofloxacin combinations with doxycycline and/or gentamicin (n = 11), or doxycycline as the single drug (n = 6) was used for treatment. One disease relapse occurred with doxycycline treatment. Treatment responses were rapid, with median fever duration 41.0 hours in nonbacteremic and 115.0 hours in bacteremic tularemia. Increased age-adjusted Charlson comorbidity index predicted severe bacteremic tularemia (odds ratio, 2.7 per score-point; 95% confidence interval, 1.35-5.41). A 78-year-old male with comorbidities and delayed ciprofloxacin/gentamicin treatment died. CONCLUSIONS: Fluoroquinolone treatment is effective for severe tularemia. Subpleural round consolidations and mediastinal lymphadenopathy were typical findings on computed tomography among case-patients in this study.


Assuntos
Bacteriemia , Francisella tularensis , Francisella , Linfadenopatia , Tularemia , Masculino , Humanos , Idoso , Feminino , Tularemia/tratamento farmacológico , Doxiciclina/uso terapêutico , Fluoroquinolonas/uso terapêutico , Fluoroquinolonas/farmacologia , Levofloxacino/uso terapêutico , Ciprofloxacina/uso terapêutico , Resultado do Tratamento , Bacteriemia/tratamento farmacológico , Gentamicinas/uso terapêutico
4.
Proc Biol Sci ; 291(2025): 20240090, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38889793

RESUMO

The more insects there are, the more food there is for insectivores and the higher the likelihood for insect-associated ecosystem services. Yet, we lack insights into the drivers of insect biomass over space and seasons, for both tropical and temperate zones. We used 245 Malaise traps, managed by 191 volunteers and park guards, to characterize year-round flying insect biomass in a temperate (Sweden) and a tropical (Madagascar) country. Surprisingly, we found that local insect biomass was similar across zones. In Sweden, local insect biomass increased with accumulated heat and varied across habitats, while biomass in Madagascar was unrelated to the environmental predictors measured. Drivers behind seasonality partly converged: In both countries, the seasonality of insect biomass differed between warmer and colder sites, and wetter and drier sites. In Sweden, short-term deviations from expected season-specific biomass were explained by week-to-week fluctuations in accumulated heat, rainfall and soil moisture, whereas in Madagascar, weeks with higher soil moisture had higher insect biomass. Overall, our study identifies key drivers of the seasonal distribution of flying insect biomass in a temperate and a tropical climate. This knowledge is key to understanding the spatial and seasonal availability of insects-as well as predicting future scenarios of insect biomass change.


Assuntos
Biomassa , Estações do Ano , Temperatura , Clima Tropical , Animais , Suécia , Madagáscar , Insetos/fisiologia , Água , Ecossistema
5.
J Virol ; 97(1): e0153622, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36602361

RESUMO

As influenza A viruses (IAV) continue to cross species barriers and cause human infection, the establishment of risk assessment rubrics has improved pandemic preparedness efforts. In vivo pathogenicity and transmissibility evaluations in the ferret model represent a critical component of this work. As the relative contribution of in vitro experimentation to these rubrics has not been closely examined, we sought to evaluate to what extent viral titer measurements over the course of in vitro infections are predictive or correlates of nasal wash and tissue measurements for IAV infections in vivo. We compiled data from ferrets inoculated with an extensive panel of over 50 human and zoonotic IAV (inclusive of swine-origin and high- and low-pathogenicity avian influenza viruses associated with human infection) under a consistent protocol, with all viruses concurrently tested in a human bronchial epithelial cell line (Calu-3). Viral titers in ferret nasal wash specimens and nasal turbinate tissue correlated positively with peak titer in Calu-3 cells, whereas additional phenotypic and molecular determinants of influenza virus virulence and transmissibility in ferrets varied in their association with in vitro viral titer measurements. Mathematical modeling was used to estimate more generalizable key replication kinetic parameters from raw in vitro viral titers, revealing commonalities between viral infection progression in vivo and in vitro. Meta-analyses inclusive of IAV that display a diverse range of phenotypes in ferrets, interpreted with mathematical modeling of viral kinetic parameters, can provide critical information supporting a more rigorous and appropriate contextualization of in vitro experiments toward pandemic preparedness. IMPORTANCE Both in vitro and in vivo models are employed for assessing the pandemic potential of novel and emerging influenza A viruses in laboratory settings, but systematic examinations of how well viral titer measurements obtained in vitro align with results from in vivo experimentation are not frequently performed. We show that certain viral titer measurements following infection of a human bronchial epithelial cell line are positively correlated with viral titers in specimens collected from virus-inoculated ferrets and employ mathematical modeling to identify commonalities between viral infection progression between both models. These analyses provide a necessary first step in enhanced interpretation and incorporation of in vitro-derived data in risk assessment activities and highlight the utility of employing mathematical modeling approaches to more closely examine features of virus replication not identifiable by experimental studies alone.


Assuntos
Vírus da Influenza A , Infecções por Orthomyxoviridae , Medição de Risco , Animais , Humanos , Furões , Vírus da Influenza A/patogenicidade , Influenza Humana , Infecções por Orthomyxoviridae/patologia , Medição de Risco/métodos , Suínos , Replicação Viral , Linhagem Celular , Técnicas In Vitro
6.
Dis Colon Rectum ; 67(6): 773-781, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38411981

RESUMO

BACKGROUND: Socioeconomic inequities have implications for access to health care and may be associated with disparities in treatment and survival. OBJECTIVE: To investigate the impact of socioeconomic inequities on time to treatment and survival of anal squamous-cell carcinoma. DESIGN: This is a retrospective study using a nationwide data set. SETTINGS: The patients were selected from the National Cancer Database and enrolled from 2004 to 2016. PATIENTS: We identified patients with stage I to III squamous-cell carcinoma of the anus who were treated with chemoradiation therapy. MAIN OUTCOMES MEASURES: Socioeconomic factors, including race, insurance status, median household income, and percentage of the population with no high school degrees, were included. The association of these factors with treatment delay and overall survival was investigated. RESULTS: A total of 24,143 patients who underwent treatment for grade I to III squamous-cell carcinoma of the anus were identified. The median age was 60 years, and 70% of patients were women. The median time to initiation of treatment was 33 days. Patients from zip codes with lower median income, patients with a higher percentage of no high school degree, and patients with other government insurance followed by Medicaid insurance had treatment initiated after 60 days from diagnosis. Kaplan-Meier survival analysis showed that the late-treatment group had worse overall survival compared to the early treatment group (98 vs 125 months; p < 0.001). LIMITATIONS: No detailed information is available about the chemoradiotherapy regimen, completion of treatment, recurrence, disease-free survival, and individual-level socioeconomic condition and risk factors. CONCLUSION: Patients from communities with lower median income, level of education, and enrolled in public insurance had longer time to treatment. Lower socioeconomic status was also associated with poorer overall survival. These results warrant further analysis and measures to improve access to care to address this disparity. See Video Abstract . DESIGUALDADES SOCIOECONMICAS EN CASOS DE CNCER ANAL EFECTOS EN EL RETRASO DEL TRATAMIENTO Y LA SOBREVIDA: ANTECEDENTES:Las desigualdades socio-económicas tienen implicaciones en el acceso a la atención médica y pueden estar asociadas con disparidades en el tratamiento y la sobrevida.OBJETIVO:Indagar el impacto de las desigualdades socio-económicas sobre el tiempo de retraso en el tratamiento y la sobrevida en casos de carcinoma a células escamosas del ano (CCEA).DISEÑO:Estudio retrospectivo utilizando un conjunto de datos a nivel nacional.AJUSTES:Todos aquellos pacientes inscritos entre 2004 a 2016 y que fueron seleccionados de la Base Nacional de Datos sobre el Cáncer.PACIENTES:Identificamos pacientes con CCEA en estadíos I-III y que fueron tratados con radio-quimioterápia.PRINCIPALES MEDIDAS DE RESULTADOS:Se incluyeron factores socio-económicos tales como la raza, el tipo de seguro de salud, el ingreso familiar medio y el porcentaje de personas sin bachillerato de secundaria (SBS). Se investigó la asociación entre estos factores con el retraso en iniciar el tratamiento y la sobrevida global.RESULTADOS:Se identificaron un total de 24.143 pacientes que recibieron tratamiento para CCEA estadíos I-III. La mediana de edad fue de 60 años donde 70% eran de sexo femenino. La mediana del tiempo transcurrido desde el diagnóstico hasta el inicio del tratamiento fue de 33 días. Los pacientes residentes en zonas de código postal con ingresos medios más bajos, con un mayor porcentaje de individuos SBS y los pacientes con otro tipo de seguro gubernamental de salud, seguidos del seguro tipo Medicaid iniciaron el tratamiento solamente después de 60 días al diagnóstico inicial de CCEA. El análisis de Kaplan-Meier de la sobrevida mostró que el grupo de tratamiento tardío tuvo una peor supervivencia general comparada con el grupo de tratamiento precoz o temprano (98 frente a 125 meses; p <0,001).LIMITACIONES:No se dispone de información detallada sobre el tipo de radio-quimioterapia utilizada, ni sobre la finalización del tratamiento o la recurrencia, tampoco acerca de la sobrevida libre de enfermedad ni sobre las condiciones socio-económicas o aquellos factores de riesgo a nivel individual.CONCLUSIÓN:Los pacientes de comunidades con ingresos medios más bajos, con un nivel de educación limitado e inscritos en un seguro público tardaron mucho más tiempo en recibir el tratamiento prescrito. El nivel socio-económico más bajo también se asoció con una sobrevida global más baja. Los presentes resultados justifican mayor análisis y medidas mas importantes para mejorar el acceso a la atención en salud y poder afrontar esta disparidad. (Traducción-Dr. Xavier Delgadillo ).


Assuntos
Neoplasias do Ânus , Carcinoma de Células Escamosas , Quimiorradioterapia , Disparidades em Assistência à Saúde , Disparidades Socioeconômicas em Saúde , Atraso no Tratamento , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias do Ânus/terapia , Neoplasias do Ânus/mortalidade , Neoplasias do Ânus/patologia , Carcinoma de Células Escamosas/terapia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Quimiorradioterapia/estatística & dados numéricos , Quimiorradioterapia/métodos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Disparidades em Assistência à Saúde/estatística & dados numéricos , Estimativa de Kaplan-Meier , Estadiamento de Neoplasias , Estudos Retrospectivos , Fatores Socioeconômicos , Taxa de Sobrevida , Atraso no Tratamento/estatística & dados numéricos , Estados Unidos/epidemiologia
7.
Euro Surveill ; 29(32)2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39119721

RESUMO

BackgroundThe Vibrio genus comprises several bacterial species present in the Baltic Sea region (BSR), which are known to cause human infections.AimTo provide a comprehensive retrospective analysis of Vibrio-induced infections in the BSR from 1994 to 2021, focusing on the 'big four' Vibrio species - V. alginolyticus, V. cholerae non-O1/O139, V. parahaemolyticus and V. vulnificus - in eight European countries (Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland and Sweden) bordering the Baltic Sea.MethodsOur analysis includes data on infections, Vibrio species distribution in coastal waters and environmental data received from national health agencies or extracted from scientific literature and online databases. A redundancy analysis was performed to determine the potential impact of several independent variables, such as sea surface temperature, salinity, the number of designated coastal beaches and year, on the Vibrio infection rate.ResultsFor BSR countries conducting surveillance, we observed an exponential increase in total Vibrio infections (n = 1,553) across the region over time. In Sweden and Germany, total numbers of Vibrio spp. and infections caused by V. alginolyticus and V. parahaemolyticus positively correlate with increasing sea surface temperature. Salinity emerged as a critical driver of Vibrio spp. distribution and abundance. Furthermore, our proposed statistical model reveals 12 to 20 unreported cases in Lithuania and Poland, respectively, countries with no surveillance.ConclusionsThere are discrepancies in Vibrio surveillance and monitoring among countries, emphasising the need for comprehensive monitoring programmes of these pathogens to protect human health, particularly in the context of climate change.


Assuntos
Vibrioses , Vibrio , Humanos , Estudos Retrospectivos , Vibrioses/epidemiologia , Vibrioses/microbiologia , Vibrio/isolamento & purificação , Vibrio/classificação , Países Bálticos/epidemiologia , Água do Mar/microbiologia , Europa (Continente)/epidemiologia , Oceanos e Mares
8.
BMC Bioinformatics ; 24(1): 6, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36604610

RESUMO

BACKGROUND: The Living Atlas is an open source platform used to collect, visualise and analyse biodiversity data from multiple sources, and serves as the national biodiversity data hub in many countries. Although powerful, the Living Atlas has had limited functionality for species occurrence data derived from DNA sequences. As a step toward integrating this fast-growing data source into the platform, we developed the Amplicon Sequence Variant (ASV) portal: a web interface to sequence-based biodiversity observations in the Living Atlas. RESULTS: The ASV portal allows data providers to submit denoised metabarcoding output to the Living Atlas platform via an intermediary ASV database. It also enables users to search for existing ASVs and associated Living Atlas records using the Basic Local Alignment Search Tool, or via filters on taxonomy and sequencing details. The ASV portal is a Python-Flask/jQuery web interface, implemented as a multi-container docker service, and is an integral part of the Swedish Biodiversity Data Infrastructure. CONCLUSION: The ASV portal is a web interface that effectively integrates biodiversity data derived from DNA sequences into the Living Atlas platform.


Assuntos
Biodiversidade , DNA , DNA/genética , Software , Código de Barras de DNA Taxonômico
9.
Phys Rev Lett ; 131(24): 243402, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38181136

RESUMO

The ground-state phases of a quantum many-body system are characterized by an order parameter, which changes abruptly at quantum phase transitions when an external control parameter is varied. Interestingly, these concepts may be extended to excited states, for which it is possible to define equivalent excited-state quantum phase transitions. However, the experimental mapping of a phase diagram of excited quantum states has not yet been realized. Here we present the experimental determination of the excited-state phase diagram of an atomic ferromagnetic quantum gas, where, crucially, the excitation energy is one of the control parameters. The obtained phase diagram exemplifies how the extensive Hilbert state of quantum many-body systems can be structured by the measurement of well-defined order parameters.

10.
Euro Surveill ; 28(13)2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36995373

RESUMO

BackgroundThe current SARS-CoV-2 pandemic has highlighted a need for easy and safe blood sampling in combination with accurate serological methodology. Venipuncture for testing is usually performed by trained staff at healthcare centres. Long travel distances to healthcare centres in rural regions may introduce a bias of testing towards relatively large communities with closer access. Rural regions are therefore often not represented in population-based data.AimThe aim of this retrospective cohort study was to develop and implement a strategy for at-home testing in a rural region of Sweden during spring 2021, and to evaluate its role to provide equal health care for its inhabitants.MethodsWe developed a sensitive method to measure antibodies to the S-protein of SARS-CoV-2 and optimised this assay for clinical use together with a strategy of at-home capillary blood sampling.ResultsWe demonstrated that our ELISA gave comparable results after analysis of capillary blood or serum from SARS-CoV-2-experienced individuals. We demonstrated stability of the assay under conditions that reflected temperature and humidity during winter or summer. By assessment of capillary blood samples from 4,122 individuals, we could show both feasibility of the strategy and that implementation shifted the geographical spread of testing in favour of rural areas.ConclusionImplementation of at-home sampling enabled citizens living in remote rural areas access to centralised and sensitive laboratory antibody tests. The strategy for testing used here could therefore enable disease control authorities to get rapid access to information concerning immunity to infectious diseases, even across vast geographical distance.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/diagnóstico , COVID-19/epidemiologia , Estudos Retrospectivos , Suécia/epidemiologia , Teste para COVID-19 , Anticorpos Antivirais
11.
Nucleic Acids Res ; 48(14): 7640-7652, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32558908

RESUMO

With the central role of nucleic acids there is a need for development of fluorophores that facilitate the visualization of processes involving nucleic acids without perturbing their natural properties and behaviour. Here, we incorporate a new analogue of adenine, 2CNqA, into both DNA and RNA, and evaluate its nucleobase-mimicking and internal fluorophore capacities. We find that 2CNqA displays excellent photophysical properties in both nucleic acids, is highly specific for thymine/uracil, and maintains and slightly stabilises the canonical conformations of DNA and RNA duplexes. Moreover, the 2CNqA fluorophore has a quantum yield in single-stranded and duplex DNA ranging from 10% to 44% and 22% to 32%, respectively, and a slightly lower one (average 12%) inside duplex RNA. In combination with a comparatively strong molar absorptivity for this class of compounds, the resulting brightness of 2CNqA inside double-stranded DNA is the highest reported for a fluorescent base analogue. The high, relatively sequence-independent quantum yield in duplexes makes 2CNqA promising as a nucleic acid label and as an interbase Förster resonance energy transfer (FRET) donor. Finally, we report its excellent spectral overlap with the interbase FRET acceptors qAnitro and tCnitro, and demonstrate that these FRET pairs enable conformation studies of DNA and RNA.


Assuntos
DNA/química , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/química , RNA de Cadeia Dupla/química , Pareamento de Bases , DNA de Cadeia Simples/química , Oligodesoxirribonucleotídeos/síntese química , Oligodesoxirribonucleotídeos/química , Oligorribonucleotídeos/síntese química , Oligorribonucleotídeos/química
12.
Phys Rev Lett ; 127(14): 140402, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34652182

RESUMO

Compared to light interferometers, the flux in cold-atom interferometers is low and the associated shot noise is large. Sensitivities beyond these limitations require the preparation of entangled atoms in different momentum modes. Here, we demonstrate a source of entangled atoms that is compatible with state-of-the-art interferometers. Entanglement is transferred from the spin degree of freedom of a Bose-Einstein condensate to well-separated momentum modes, witnessed by a squeezing parameter of -3.1(8) dB. Entanglement-enhanced atom interferometers promise unprecedented sensitivities for quantum gradiometers or gravitational wave detectors.

13.
Nucleic Acids Res ; 47(19): 9990-9997, 2019 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-31544922

RESUMO

Interbase FRET can reveal highly detailed information about distance, orientation and dynamics in nucleic acids, complementing the existing structure and dynamics techniques. We here report the first RNA base analogue FRET pair, consisting of the donor tCO and the non-emissive acceptor tCnitro. The acceptor ribonucleoside is here synthesised and incorporated into RNA for the first time. This FRET pair accurately reports the average structure of A-form RNA, and its utility for probing RNA structural changes is demonstrated by monitoring the transition from A- to Z-form RNA. Finally, the measured FRET data were compared with theoretical FRET patterns obtained from two previously reported Z-RNA PDB structures, to shed new light on this elusive RNA conformation.


Assuntos
DNA/química , Transferência Ressonante de Energia de Fluorescência/métodos , Conformação de Ácido Nucleico , RNA/química , Pareamento de Bases , DNA/genética , Modelos Moleculares , RNA/isolamento & purificação
14.
Proc Natl Acad Sci U S A ; 115(44): E10447-E10456, 2018 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-30322929

RESUMO

Vitamin B1 (B1 herein) is a vital enzyme cofactor required by virtually all cells, including bacterioplankton, which strongly influence aquatic biogeochemistry and productivity and modulate climate on Earth. Intriguingly, bacterioplankton can be de novo B1 synthesizers or B1 auxotrophs, which cannot synthesize B1 de novo and require exogenous B1 or B1 precursors to survive. Recent isolate-based work suggests select abundant bacterioplankton are B1 auxotrophs, but direct evidence of B1 auxotrophy among natural communities is scant. In addition, it is entirely unknown if bulk bacterioplankton growth is ever B1-limited. We show by surveying for B1-related genes in estuarine, marine, and freshwater metagenomes and metagenome-assembled genomes (MAGs) that most naturally occurring bacterioplankton are B1 auxotrophs. Pyrimidine B1-auxotrophic bacterioplankton numerically dominated metagenomes, but multiple other B1-auxotrophic types and distinct uptake and B1-salvaging strategies were also identified, including dual (pyrimidine and thiazole) and intact B1 auxotrophs that have received little prior consideration. Time-series metagenomes from the Baltic Sea revealed pronounced shifts in the prevalence of multiple B1-auxotrophic types and in the B1-uptake and B1-salvaging strategies over time. Complementarily, we documented B1/precursor limitation of bacterioplankton production in three of five nutrient-amendment experiments at the same time-series station, specifically when intact B1 concentrations were ≤3.7 pM, based on bioassays with a genetically engineered Vibrio anguillarum B1-auxotrophic strain. Collectively, the data presented highlight the prevalent reliance of bacterioplankton on exogenous B1/precursors and on the bioavailability of the micronutrients as an overlooked factor that could influence bacterioplankton growth and succession and thereby the cycling of nutrients and energy in aquatic systems.


Assuntos
Bactérias/metabolismo , Genômica/métodos , Tiamina/metabolismo , Bactérias/genética , Água Doce , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Genótipo , Plâncton , Água do Mar , Transcriptoma
15.
Infect Immun ; 88(10)2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32719155

RESUMO

Group A Streptococcus (GAS) is the etiologic agent of numerous high-morbidity and high-mortality diseases. Infections are typically highly proinflammatory. During the invasive infection necrotizing fasciitis, this is in part due to the GAS protease SpeB directly activating interleukin-1ß (IL-1ß) independent of the canonical inflammasome pathway. The upper respiratory tract is the primary site for GAS colonization, infection, and transmission, but the host-pathogen interactions at this site are still largely unknown. We found that in the murine nasopharynx, SpeB enhanced IL-1ß-mediated inflammation and the chemotaxis of neutrophils. However, neutrophilic inflammation did not restrict infection and instead promoted GAS replication and disease. Inhibiting IL-1ß or depleting neutrophils, which both promote invasive infection, prevented GAS infection of the nasopharynx. Mice pretreated with penicillin became more susceptible to GAS challenge, and this reversed the attenuation from neutralization or depletion of IL-1ß, neutrophils, or SpeB. Collectively, our results suggest that SpeB is essential to activate an IL-1ß-driven neutrophil response. Unlike during invasive tissue infections, this is beneficial in the upper respiratory tract because it disrupts colonization resistance mediated by the microbiota. This provides experimental evidence that the notable inflammation of strep throat, which presents with significant swelling, pain, and neutrophil influx, is not an ineffectual immune response but rather is a GAS-directed remodeling of this niche for its pathogenic benefit.


Assuntos
Nasofaringe/imunologia , Receptores Tipo I de Interleucina-1/imunologia , Transdução de Sinais/imunologia , Infecções Estreptocócicas/imunologia , Streptococcus pyogenes/patogenicidade , Animais , Antibacterianos/efeitos adversos , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Caspase 1/genética , Caspase 1/imunologia , Quimiotaxia de Leucócito , Exotoxinas/genética , Exotoxinas/imunologia , Inflamação , Proteína Antagonista do Receptor de Interleucina 1/farmacologia , Interleucina-1beta/imunologia , Camundongos , Nasofaringe/microbiologia , Neutrófilos/imunologia , Faringite/genética , Faringite/imunologia , Faringite/microbiologia , Receptores Tipo I de Interleucina-1/genética , Transdução de Sinais/efeitos dos fármacos , Infecções Estreptocócicas/genética , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/efeitos dos fármacos , Streptococcus pyogenes/genética , Streptococcus pyogenes/crescimento & desenvolvimento , Virulência/efeitos dos fármacos , Virulência/genética
16.
Mol Ecol ; 29(23): 4605-4617, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33001506

RESUMO

A prerequisite to improve the predictability of microbial community dynamics is to understand the mechanisms of microbial assembly. To study factors that contribute to microbial community assembly, we examined the temporal dynamics of genes in five aquatic metagenome time-series, originating from marine offshore or coastal sites and one lake. With this trait-based approach we expected to find gene-specific patterns of temporal allele variability that depended on the seasonal metacommunity size of carrier-taxa and the variability of the milieu and the substrates to which the resulting proteins were exposed. In more detail, we hypothesized that a larger seasonal metacommunity size would result in increased temporal variability of functional units (i.e., gene alleles), as shown previously for taxonomic units. We further hypothesized that multicopy genes would feature higher temporal variability than single-copy genes, as gene multiplication can result from high variability in substrate quality and quantity. Finally, we hypothesized that direct exposure of proteins to the extracellular environment would result in increased temporal variability of the respective gene compared to intracellular proteins that are less exposed to environmental fluctuations. The first two hypotheses were confirmed in all data sets, while significant effects of the subcellular location of gene products was only seen in three of the five time-series. The gene with the highest allele variability throughout all data sets was an iron transporter, also representing a target for phage infection. Previous work has emphasized the role of phage-prokaryote interactions as a major driver of microbial diversity. Our finding therefore points to a potentially important role of iron transporter-mediated phage infections for the assembly and maintenance of diversity in aquatic prokaryotes.


Assuntos
Bacteriófagos , Microbiota , Bacteriófagos/genética , Lagos , Metagenoma , Metagenômica
17.
Gut ; 68(1): 83-93, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29097438

RESUMO

OBJECTIVE: To investigate whether a whole grain diet alters the gut microbiome and insulin sensitivity, as well as biomarkers of metabolic health and gut functionality. DESIGN: 60 Danish adults at risk of developing metabolic syndrome were included in a randomised cross-over trial with two 8-week dietary intervention periods comprising whole grain diet and refined grain diet, separated by a washout period of ≥6 weeks. The response to the interventions on the gut microbiome composition and insulin sensitivity as well on measures of glucose and lipid metabolism, gut functionality, inflammatory markers, anthropometry and urine metabolomics were assessed. RESULTS: 50 participants completed both periods with a whole grain intake of 179±50 g/day and 13±10 g/day in the whole grain and refined grain period, respectively. Compliance was confirmed by a difference in plasma alkylresorcinols (p<0.0001). Compared with refined grain, whole grain did not significantly alter glucose homeostasis and did not induce major changes in the faecal microbiome. Also, breath hydrogen levels, plasma short-chain fatty acids, intestinal integrity and intestinal transit time were not affected. The whole grain diet did, however, compared with the refined grain diet, decrease body weight (p<0.0001), serum inflammatory markers, interleukin (IL)-6 (p=0.009) and C-reactive protein (p=0.003). The reduction in body weight was consistent with a reduction in energy intake, and IL-6 reduction was associated with the amount of whole grain consumed, in particular with intake of rye. CONCLUSION: Compared with refined grain diet, whole grain diet did not alter insulin sensitivity and gut microbiome but reduced body weight and systemic low-grade inflammation. TRIAL REGISTRATION NUMBER: NCT01731366; Results.


Assuntos
Microbioma Gastrointestinal , Inflamação/sangue , Redução de Peso , Grãos Integrais , Adulto , Idoso , Glicemia/metabolismo , Estudos Cross-Over , Dinamarca , Dieta , Ingestão de Energia , Fezes/microbiologia , Feminino , Humanos , Inflamação/dietoterapia , Resistência à Insulina , Interleucina-6/sangue , Lipídeos/sangue , Masculino , Metabolômica , Pessoa de Meia-Idade
18.
Genes Immun ; 20(3): 214-223, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29728610

RESUMO

Recently, deficiency in the cytosolic DNA sensor RNA Polymerase III was described in children with severe primary varicella-zoster virus (VZV) infection in the CNS and lungs. In the present study we examined adult patients with VZV CNS infection caused by viral reactivation. By whole exome sequencing we identified mutations in POL III genes in two of eight patients. These mutations were located in the coding regions of the subunits POLR3A and POLR3E. In functional assays, we found impaired expression of antiviral and inflammatory cytokines in response to the POL III agonist Poly(dA:dT) as well as increased viral replication in patient cells compared to controls. Altogether, this study provides significant extension on the current knowledge on susceptibility to VZV infection by demonstrating mutations in POL III genes associated with impaired immunological sensing of AT-rich DNA in adult patients with VZV CNS infection.


Assuntos
RNA Polimerase III/genética , Infecção pelo Vírus da Varicela-Zoster/genética , Adulto , Idoso , Células Cultivadas , Citocinas/metabolismo , Suscetibilidade a Doenças , Feminino , Humanos , Masculino , Monócitos/imunologia , Monócitos/virologia , Mutação , RNA Polimerase III/metabolismo , Infecção pelo Vírus da Varicela-Zoster/imunologia , Infecção pelo Vírus da Varicela-Zoster/virologia , Replicação Viral
19.
Opt Express ; 27(5): 7120-7138, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30876283

RESUMO

X-ray microscopy at photon energies above 15 keV is very attractive for the investigation of atomic and nanoscale properties of technologically relevant structural and bio materials. This method is limited by the quality of X-ray optics. Multilayer Laue lenses (MLLs) have the potential to make a major impact in this field because, as compared to other X-ray optics, they become more efficient and effective with increasing photon energy. In this work, MLLs were utilized with hard X-rays at photon energies up to 34.5 keV. The design, fabrication, and performance of these lenses are presented, and their application in several imaging configurations is described. In particular, two "full field" modes of imaging were explored, which provide various contrast modalities that are useful for materials characterisation. These include point projection imaging (or Gabor holography) for phase contrast imaging and direct imaging with both bright-field and dark-field illumination. With high-efficiency MLLs, such modes offer rapid data collection as compared with scanning methods as well as a large field of views.

20.
Neuroendocrinology ; 109(2): 131-140, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30844796

RESUMO

BACKGROUND/AIMS: It is unknown whether long-term growth hormone replacement therapy (GHRT) affects body composition in an age- or sex-dependent manner. We aimed to study the effects of 4 years of GHRT on body composition in a large cohort of patients with hypopituitarism compared to a reference population matched by age and sex. METHODS: A total of 964 GH-deficient adults from KIMS (Pfizer International Metabolic Database) with adult-onset hypopituitarism, adequately replaced with all pituitary hormones except for GH at baseline were included. A random sample of the general population (2,301 subjects) from a similar time period was used as reference. Patients and controls were grouped by sex in 5 age cohorts of 10 years. Main outcome measures were changes in BMI and waist circumference after 4 years of GHRT. RESULTS: In younger patients (28-47 years), 4 years of GHRT resulted in a BMI increase similar to that observed in the reference population, but older patients (48-67 years) had significantly less BMI increase than age-matched healthy controls. Significant differences were seen in waist circumference in patients of all age cohorts who showed virtually no change after 4 years of GHRT compared to approximately 4 cm of increase in the reference population. CONCLUSION: Four years of GHRT resulted in improvements in BMI and waist circumference in patients with adult-onset hypopituitarism compared to age-matched controls observed during the same follow-up time. Despite these beneficial effects on body composition, BMI and waist circumference remained higher in patients on GHRT compared to healthy controls.


Assuntos
Composição Corporal/efeitos dos fármacos , Terapia de Reposição Hormonal , Hormônio do Crescimento Humano/administração & dosagem , Hipopituitarismo/tratamento farmacológico , Adulto , Idoso , Estudos de Casos e Controles , Estudos de Coortes , Bases de Dados Factuais , Feminino , Hormônio do Crescimento Humano/deficiência , Humanos , Hipopituitarismo/metabolismo , Hipopituitarismo/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento
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