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1.
Cell ; 186(22): 4803-4817.e13, 2023 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-37683634

RESUMO

Patescibacteria, also known as the candidate phyla radiation (CPR), are a diverse group of bacteria that constitute a disproportionately large fraction of microbial dark matter. Its few cultivated members, belonging mostly to Saccharibacteria, grow as epibionts on host Actinobacteria. Due to a lack of suitable tools, the genetic basis of this lifestyle and other unique features of Patescibacteira remain unexplored. Here, we show that Saccharibacteria exhibit natural competence, and we exploit this property for their genetic manipulation. Imaging of fluorescent protein-labeled Saccharibacteria provides high spatiotemporal resolution of phenomena accompanying epibiotic growth, and a transposon-insertion sequencing (Tn-seq) genome-wide screen reveals the contribution of enigmatic Saccharibacterial genes to growth on their hosts. Finally, we leverage metagenomic data to provide cutting-edge protein structure-based bioinformatic resources that support the strain Southlakia epibionticum and its corresponding host, Actinomyces israelii, as a model system for unlocking the molecular underpinnings of the epibiotic lifestyle.


Assuntos
Bactérias , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Metagenoma , Metagenômica , Filogenia , Actinobacteria/fisiologia
2.
Cell ; 175(5): 1380-1392.e14, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30343895

RESUMO

ADP-ribosylation of proteins can profoundly impact their function and serves as an effective mechanism by which bacterial toxins impair eukaryotic cell processes. Here, we report the discovery that bacteria also employ ADP-ribosylating toxins against each other during interspecies competition. We demonstrate that one such toxin from Serratia proteamaculans interrupts the division of competing cells by modifying the essential bacterial tubulin-like protein, FtsZ, adjacent to its protomer interface, blocking its capacity to polymerize. The structure of the toxin in complex with its immunity determinant revealed two distinct modes of inhibition: active site occlusion and enzymatic removal of ADP-ribose modifications. We show that each is sufficient to support toxin immunity; however, the latter additionally provides unprecedented broad protection against non-cognate ADP-ribosylating effectors. Our findings reveal how an interbacterial arms race has produced a unique solution for safeguarding the integrity of bacterial cell division machinery against inactivating post-translational modifications.


Assuntos
ADP Ribose Transferases/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Proteínas do Citoesqueleto/metabolismo , N-Glicosil Hidrolases/metabolismo , ADP Ribose Transferases/química , ADP Ribose Transferases/genética , ADP-Ribosilação , Difosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/antagonistas & inibidores , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Domínio Catalítico , Proteínas do Citoesqueleto/antagonistas & inibidores , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/imunologia , Escherichia coli/metabolismo , Humanos , Mutagênese Sítio-Dirigida , N-Glicosil Hidrolases/química , N-Glicosil Hidrolases/genética , Estrutura Terciária de Proteína , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Alinhamento de Sequência , Serratia/metabolismo , Imagem com Lapso de Tempo
3.
Nature ; 629(8010): 165-173, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38632398

RESUMO

Streptomyces are a genus of ubiquitous soil bacteria from which the majority of clinically utilized antibiotics derive1. The production of these antibacterial molecules reflects the relentless competition Streptomyces engage in with other bacteria, including other Streptomyces species1,2. Here we show that in addition to small-molecule antibiotics, Streptomyces produce and secrete antibacterial protein complexes that feature a large, degenerate repeat-containing polymorphic toxin protein. A cryo-electron microscopy structure of these particles reveals an extended stalk topped by a ringed crown comprising the toxin repeats scaffolding five lectin-tipped spokes, which led us to name them umbrella particles. Streptomyces coelicolor encodes three umbrella particles with distinct toxin and lectin composition. Notably, supernatant containing these toxins specifically and potently inhibits the growth of select Streptomyces species from among a diverse collection of bacteria screened. For one target, Streptomyces griseus, inhibition relies on a single toxin and that intoxication manifests as rapid cessation of vegetative hyphal growth. Our data show that Streptomyces umbrella particles mediate competition among vegetative mycelia of related species, a function distinct from small-molecule antibiotics, which are produced at the onset of reproductive growth and act broadly3,4. Sequence analyses suggest that this role of umbrella particles extends beyond Streptomyces, as we identified umbrella loci in nearly 1,000 species across Actinobacteria.


Assuntos
Antibiose , Proteínas de Bactérias , Toxinas Bacterianas , Streptomyces , Antibacterianos/biossíntese , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antibiose/efeitos dos fármacos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Proteínas de Bactérias/ultraestrutura , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/farmacologia , Microscopia Crioeletrônica , Lectinas/química , Lectinas/genética , Lectinas/metabolismo , Lectinas/ultraestrutura , Testes de Sensibilidade Microbiana , Modelos Moleculares , Streptomyces/química , Streptomyces/efeitos dos fármacos , Streptomyces/genética , Streptomyces/crescimento & desenvolvimento , Streptomyces coelicolor/química , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Streptomyces griseus/efeitos dos fármacos , Streptomyces griseus/genética , Streptomyces griseus/crescimento & desenvolvimento , Streptomyces griseus/metabolismo
4.
Nature ; 583(7817): 631-637, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32641830

RESUMO

Bacterial toxins represent a vast reservoir of biochemical diversity that can be repurposed for biomedical applications. Such proteins include a group of predicted interbacterial toxins of the deaminase superfamily, members of which have found application in gene-editing techniques1,2. Because previously described cytidine deaminases operate on single-stranded nucleic acids3, their use in base editing requires the unwinding of double-stranded DNA (dsDNA)-for example by a CRISPR-Cas9 system. Base editing within mitochondrial DNA (mtDNA), however, has thus far been hindered by challenges associated with the delivery of guide RNA into the mitochondria4. As a consequence, manipulation of mtDNA to date has been limited to the targeted destruction of the mitochondrial genome by designer nucleases9,10.Here we describe an interbacterial toxin, which we name DddA, that catalyses the deamination of cytidines within dsDNA. We engineered split-DddA halves that are non-toxic and inactive until brought together on target DNA by adjacently bound programmable DNA-binding proteins. Fusions of the split-DddA halves, transcription activator-like effector array proteins, and a uracil glycosylase inhibitor resulted in RNA-free DddA-derived cytosine base editors (DdCBEs) that catalyse C•G-to-T•A conversions in human mtDNA with high target specificity and product purity. We used DdCBEs to model a disease-associated mtDNA mutation in human cells, resulting in changes in respiration rates and oxidative phosphorylation. CRISPR-free DdCBEs enable the precise manipulation of mtDNA, rather than the elimination of mtDNA copies that results from its cleavage by targeted nucleases, with broad implications for the study and potential treatment of mitochondrial disorders.


Assuntos
Toxinas Bacterianas/metabolismo , Citidina Desaminase/metabolismo , DNA Mitocondrial/genética , Edição de Genes/métodos , Genes Mitocondriais/genética , Mitocôndrias/genética , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Sequência de Bases , Burkholderia cenocepacia/enzimologia , Burkholderia cenocepacia/genética , Respiração Celular/genética , Citidina/metabolismo , Citidina Desaminase/química , Citidina Desaminase/genética , Genoma Mitocondrial/genética , Células HEK293 , Humanos , Doenças Mitocondriais/genética , Doenças Mitocondriais/terapia , Mutação , Fosforilação Oxidativa , Engenharia de Proteínas , RNA Guia de Cinetoplastídeos/genética , Especificidade por Substrato , Sistemas de Secreção Tipo VI/metabolismo
5.
Nature ; 588(7837): 344-349, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32814344

RESUMO

Leucine-rich repeat kinase 2 (LRRK2) is the most commonly mutated gene in familial Parkinson's disease1 and is also linked to its idiopathic form2. LRRK2 has been proposed to function in membrane trafficking3 and colocalizes with microtubules4. Despite the fundamental importance of LRRK2 for understanding and treating Parkinson's disease, structural information on the enzyme is limited. Here we report the structure of the catalytic half of LRRK2, and an atomic model of microtubule-associated LRRK2 built using a reported cryo-electron tomography in situ structure5. We propose that the conformation of the LRRK2 kinase domain regulates its interactions with microtubules, with a closed conformation favouring oligomerization on microtubules. We show that the catalytic half of LRRK2 is sufficient for filament formation and blocks the motility of the microtubule-based motors kinesin 1 and cytoplasmic dynein 1 in vitro. Kinase inhibitors that stabilize an open conformation relieve this interference and reduce the formation of LRRK2 filaments in cells, whereas inhibitors that stabilize a closed conformation do not. Our findings suggest that LRRK2 can act as a roadblock for microtubule-based motors and have implications for the design of therapeutic LRRK2 kinase inhibitors.


Assuntos
Microscopia Crioeletrônica , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/química , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Microtúbulos/química , Microtúbulos/metabolismo , Doença de Parkinson/metabolismo , Benzamidas/farmacologia , Biocatálise/efeitos dos fármacos , Dimerização , Dineínas/antagonistas & inibidores , Dineínas/metabolismo , Humanos , Cinesinas/antagonistas & inibidores , Cinesinas/metabolismo , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/antagonistas & inibidores , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/ultraestrutura , Microtúbulos/ultraestrutura , Modelos Moleculares , Movimento/efeitos dos fármacos , Ligação Proteica , Domínios Proteicos/efeitos dos fármacos , Pirazóis/farmacologia , Repetições WD40
6.
Nat Methods ; 19(11): 1438-1448, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36253643

RESUMO

Advances in microscopy hold great promise for allowing quantitative and precise measurement of morphological and molecular phenomena at the single-cell level in bacteria; however, the potential of this approach is ultimately limited by the availability of methods to faithfully segment cells independent of their morphological or optical characteristics. Here, we present Omnipose, a deep neural network image-segmentation algorithm. Unique network outputs such as the gradient of the distance field allow Omnipose to accurately segment cells on which current algorithms, including its predecessor, Cellpose, produce errors. We show that Omnipose achieves unprecedented segmentation performance on mixed bacterial cultures, antibiotic-treated cells and cells of elongated or branched morphology. Furthermore, the benefits of Omnipose extend to non-bacterial subjects, varied imaging modalities and three-dimensional objects. Finally, we demonstrate the utility of Omnipose in the characterization of extreme morphological phenotypes that arise during interbacterial antagonism. Our results distinguish Omnipose as a powerful tool for characterizing diverse and arbitrarily shaped cell types from imaging data.


Assuntos
Algoritmos , Microscopia , Processamento de Imagem Assistida por Computador/métodos
7.
Nature ; 575(7781): 224-228, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31666699

RESUMO

The human gastrointestinal tract consists of a dense and diverse microbial community, the composition of which is intimately linked to health. Extrinsic factors such as diet and host immunity are insufficient to explain the constituents of this community, and direct interactions between co-resident microorganisms have been implicated as important drivers of microbiome composition. The genomes of bacteria derived from the gut microbiome contain several pathways that mediate contact-dependent interbacterial antagonism1-3. Many members of the Gram-negative order Bacteroidales encode the type VI secretion system (T6SS), which facilitates the delivery of toxic effector proteins into adjacent cells4,5. Here we report the occurrence of acquired interbacterial defence (AID) gene clusters in Bacteroidales species that reside within the human gut microbiome. These clusters encode arrays of immunity genes that protect against T6SS-mediated intra- and inter-species bacterial antagonism. Moreover, the clusters reside on mobile elements, and we show that their transfer is sufficient to confer resistance to toxins in vitro and in gnotobiotic mice. Finally, we identify and validate the protective capability of a recombinase-associated AID subtype (rAID-1) that is present broadly in Bacteroidales genomes. These rAID-1 gene clusters have a structure suggestive of active gene acquisition and include predicted immunity factors of toxins derived from diverse organisms. Our data suggest that neutralization of contact-dependent interbacterial antagonism by AID systems helps to shape human gut microbiome ecology.


Assuntos
Bacteroidetes , Microbioma Gastrointestinal , Trato Gastrointestinal/microbiologia , Interações Microbianas , Sistemas de Secreção Tipo VI/antagonistas & inibidores , Animais , Bacteroidetes/genética , Bacteroidetes/imunologia , Feminino , Microbioma Gastrointestinal/imunologia , Trato Gastrointestinal/imunologia , Genes Bacterianos/genética , Humanos , Camundongos , Interações Microbianas/genética , Interações Microbianas/imunologia , Família Multigênica/genética , Sistemas de Secreção Tipo VI/genética , Sistemas de Secreção Tipo VI/imunologia
8.
Philos Trans A Math Phys Eng Sci ; 382(2273): 20230197, 2024 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-38736334

RESUMO

The origin of micrometeorites (MMs) from asteroids and comets is well-established, but the relative contribution from these two classes remains poorly resolved. Likewise, determining the precise origin of individual MMs is an open challenge. Here, cosmic-ray exposure ages are used to resolve the spatial origins of 12 MMs collected from urban areas and Antarctica. Their 26Al and 10Be concentration, produced during cosmic-ray irradiation in space, were measured by accelerator mass spectrometry. These data are compared to results from a model simulating the transport and irradiation of the MM precursors in space. This model, for the first time, considers a variety of orbits, precursor particle sizes, compositions and densities and incorporates non-isotropic solar and galactic cosmic-ray flux profiles, depth-dependent production rates, as well as spherical evaporation during atmospheric entry. While the origin for six MMs remains ambiguous, two MMs show a preferential tendency towards an origin in the Inner Solar System (Near Earth Objects to the Asteroid Belt) and four towards an origin in the Outer Solar System (Jupiter Family Comets to the Kuiper Belt). These findings challenge the notion that dust originating from the Outer Solar System is unlikely to survive long-term transport and delivery to the terrestrial planets. This article is part of the theme issue 'Dust in the Solar System and beyond'.

9.
Genomics ; 115(2): 110580, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36792020

RESUMO

Bloodstream infections are a major cause of morbidity and mortality worldwide. Early administration of appropriate antimicrobial therapy can improve patient survival and prevent antimicrobial resistance (AMR). Whole genome sequencing (WGS) can provide information for pathogen identification, AMR prediction and sequence typing earlier than current phenotypic diagnostic methods. WGS was performed on 97 clinical blood specimens and matched culture isolate pairs. Specimen/isolate pairs were MLST sequence-typed and further characterization was performed on Streptococcus species. WGS correctly identified 91.7% of clinical specimens and 93.2% of matched isolates representing 35 different microbial species. MLST types were assigned for 89.9% of matched cultures and 21.7% of blood specimens, with higher success for blood culture specimens extracted within 3 days (52% characterized) than 7 days (9.3%). This study demonstrates the potential use of WGS for identification and characterization of pathogens directly from blood culture specimens to facilitate timely initiation of appropriate antimicrobial therapies.


Assuntos
Hemocultura , Genoma Bacteriano , Humanos , Tipagem de Sequências Multilocus , Bactérias , Sequenciamento Completo do Genoma , Farmacorresistência Bacteriana/genética , Antibacterianos/farmacologia
10.
PLoS Pathog ; 16(6): e1008566, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32492066

RESUMO

Host-derived glutathione (GSH) is an essential source of cysteine for the intracellular pathogen Francisella tularensis. In a comprehensive transposon insertion sequencing screen, we identified several F. tularensis genes that play central and previously unappreciated roles in the utilization of GSH during the growth of the bacterium in macrophages. We show that one of these, a gene we named dptA, encodes a proton-dependent oligopeptide transporter that enables growth of the organism on the dipeptide Cys-Gly, a key breakdown product of GSH generated by the enzyme γ-glutamyltranspeptidase (GGT). Although GGT was thought to be the principal enzyme involved in GSH breakdown in F. tularensis, our screen identified a second enzyme, referred to as ChaC, that is also involved in the utilization of exogenous GSH. However, unlike GGT and DptA, we show that the importance of ChaC in supporting intramacrophage growth extends beyond cysteine acquisition. Taken together, our findings provide a compendium of F. tularensis genes required for intracellular growth and identify new players in the metabolism of GSH that could be attractive targets for therapeutic intervention.


Assuntos
Proteínas de Bactérias , Francisella tularensis/fisiologia , Glutationa , Interações Hospedeiro-Patógeno/fisiologia , Macrófagos , Transglutaminases , Tularemia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Linhagem Celular , Dipeptídeos/genética , Dipeptídeos/metabolismo , Feminino , Glutationa/genética , Glutationa/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiologia , Macrófagos/patologia , Camundongos , Transglutaminases/genética , Transglutaminases/metabolismo , Tularemia/genética , Tularemia/metabolismo
11.
J Urol ; 207(5): 1105-1115, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34968146

RESUMO

PURPOSE: We sought to automate R.E.N.A.L. (for radius, exophytic/endophytic, nearness of tumor to collecting system, anterior/posterior, location relative to polar line) nephrometry scoring of preoperative computerized tomography scans and create an artificial intelligence-generated score (AI-score). Subsequently, we aimed to evaluate its ability to predict meaningful oncologic and perioperative outcomes as compared to expert human-generated nephrometry scores (H-scores). MATERIALS AND METHODS: A total of 300 patients with preoperative computerized tomography were identified from a cohort of 544 consecutive patients undergoing surgical extirpation for suspected renal cancer at a single institution. A deep neural network approach was used to automatically segment kidneys and tumors, and geometric algorithms were developed to estimate components of R.E.N.A.L. nephrometry score. Tumors were independently scored by medical personnel blinded to AI-scores. AI- and H-score agreement was assessed using Lin's concordance correlation and their predictive abilities for both oncologic and perioperative outcomes were assessed using areas under the curve. RESULTS: Median age was 60 years (IQE 51-68), and 40% were female. Median tumor size was 4.2 cm and 91.3% had malignant tumors, including 27%, 37% and 24% with high stage, grade and necrosis, respectively. There was significant agreement between H-scores and AI-scores (Lin's ⍴=0.59). Both AI- and H-scores similarly predicted meaningful oncologic outcomes (p <0.001) including presence of malignancy, necrosis, and high-grade and -stage disease (p <0.003). They also predicted surgical approach (p <0.004) and specific perioperative outcomes (p <0.05). CONCLUSIONS: Fully automated AI-generated R.E.N.A.L. scores are comparable to human-generated R.E.N.A.L. scores and predict a wide variety of meaningful patient-centered outcomes. This unambiguous artificial intelligence-based scoring is intended to facilitate wider adoption of the R.E.N.A.L. score.


Assuntos
Inteligência Artificial , Neoplasias Renais , Computadores , Feminino , Humanos , Neoplasias Renais/diagnóstico por imagem , Neoplasias Renais/patologia , Neoplasias Renais/cirurgia , Pessoa de Meia-Idade , Necrose , Nefrectomia/métodos , Estudos Retrospectivos
12.
Int J Equity Health ; 21(1): 80, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672744

RESUMO

BACKGROUND: Strong primary care systems have been associated with improved health equity. Primary care system reforms in Canada may have had equity implications, but these have not been evaluated. We sought to determine if changes in primary care service use between 1999/2000 and 2017/2018 differ by neighbourhood income in British Columbia. METHODS: We used linked administrative databases to track annual primary care visits, continuity of care, emergency department (ED) visits, specialist referrals, and prescriptions dispensed over time. We use generalized estimating equations to examine differences in the magnitude of change by neighbourhood income quintile, adjusting for age, sex/gender, and comorbidity, and stratified by urban/rural location of residence. We also compared the characteristics of physicians providing care to people living in low- and high-income neighbourhoods at two points in time. RESULTS: Between 1999/2000 and 2017/8 the average number of primary care visits per person, specialist referrals, and continuity of care fell in both urban and rural settings, while ED visits and prescriptions dispensed increased. Over this period in urban settings, primary care visits, continuity, and specialist referrals fell more rapidly in low vs. high income neighbourhoods (relative change in primary care visits: Incidence Rate Ratio (IRR) 0.881, 95% CI: 0.872, 0.890; continuity: partial regression coefficient -0.92, 95% CI: -1.18, -0.66; specialist referrals: IRR 0.711, 95%CI: 0.696, 0.726), while ED visits increased more rapidly (IRR 1.06, 95% CI: 1.03, 1.09). The percentage of physicians who provide the majority of visits to patients in neighbourhoods in the lower two income quintiles declined from 30.6% to 26.3%. CONCLUSION: Results raise concerns that equity in access to primary care has deteriorated in BC. Reforms to primary care that fail to attend to the multidimensional needs of low-income communities may entrench existing inequities. Policies that tailor patterns of funding and allocation of resources in accordance with population needs, and that align accountability measures with equity objectives are needed as part of further reform efforts.


Assuntos
Serviço Hospitalar de Emergência , Renda , Colúmbia Britânica/epidemiologia , Humanos , Estudos Longitudinais , Atenção Primária à Saúde
13.
BMC Pulm Med ; 22(1): 407, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36352399

RESUMO

PURPOSE: Uncontrolled severe asthma constitutes a major economic burden to society. Add-ons to standard inhaled treatments include inexpensive oral corticosteroids and expensive biologics. Nocturnal treatment with Temperature-controlled Laminar Airflow (TLA; Airsonett®) could be an effective, safe and cheaper alternative. The potential of TLA in reducing severe asthma exacerbations was addressed in a recent randomised placebo-controlled trial (RCT) in patients with severe asthma (Global Initiative for Asthma (GINA) step 4/5), but the results were inconclusive. We re-analysed the RCT with severe exacerbations stratified by the level of baseline asthma symptoms and Quality of Life. METHODS: More uncontrolled patients, defined by Asthma Control Questionnaire 7 (ACQ7) > 3, EuroQoL 5-Dimension Questionnaire Visual Analogue Scale (EQ5D-VAS) ≤ 65 and Asthma Quality of Life Questionnaire (AQLQ) ≤ 4 were selected for re-analysis. The rates of severe asthma exacerbations, changes in QoL and health-economics were analysed and compared between TLA and placebo. RESULTS: The study population included 226 patients (113 TLA / 113 placebo.) The rates of severe asthma exacerbations were reduced by 33, 31 and 25% (p = 0.083, 0.073, 0.180) for TLA compared to placebo, dependent on selected control measures (ACQ7, EQ5D-VAS, AQLQ, respectively). For patients with less control defined by AQLQ≤4, the difference in mean AQLQ0-12M between TLA and placebo was 0.31, 0.33, 0.26 (p = 0.085, 0.034, 0.150), dependent on selected covariate (AQLQ, EQ5D-VAS, ACQ7, respectively). For patients with poor control defined by ACQ7 > 3, the difference in EQ5D-5 L utility scores between TLA and placebo was significant at 9 and 12 months with a cost-effective ICER. The results from the original study did not demonstrate these differences. CONCLUSION: This post hoc analysis demonstrated an effect of TLA over placebo on severe exacerbations, asthma control and health economics in a subgroup of patients with more symptomatic severe allergic asthma. The results are consistent with the present recommendations for TLA. However, these differences were not demonstrated in the full study. Several explanations for the different outcomes have been outlined, which should be addressed in future studies. FUNDING: NIHR Health Technology Assessment Programme and Portsmouth Hospitals NHS Trust.


Assuntos
Antiasmáticos , Asma , Hipersensibilidade , Humanos , Corticosteroides/uso terapêutico , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Qualidade de Vida , Temperatura
14.
Nature ; 518(7537): 98-101, 2015 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-25470067

RESUMO

Horizontal gene transfer allows organisms to rapidly acquire adaptive traits. Although documented instances of horizontal gene transfer from bacteria to eukaryotes remain rare, bacteria represent a rich source of new functions potentially available for co-option. One benefit that genes of bacterial origin could provide to eukaryotes is the capacity to produce antibacterials, which have evolved in prokaryotes as the result of eons of interbacterial competition. The type VI secretion amidase effector (Tae) proteins are potent bacteriocidal enzymes that degrade the cell wall when delivered into competing bacterial cells by the type VI secretion system. Here we show that tae genes have been transferred to eukaryotes on at least six occasions, and that the resulting domesticated amidase effector (dae) genes have been preserved for hundreds of millions of years through purifying selection. We show that the dae genes acquired eukaryotic secretion signals, are expressed within recipient organisms, and encode active antibacterial toxins that possess substrate specificity matching extant Tae proteins of the same lineage. Finally, we show that a dae gene in the deer tick Ixodes scapularis limits proliferation of Borrelia burgdorferi, the aetiologic agent of Lyme disease. Our work demonstrates that a family of horizontally acquired toxins honed to mediate interbacterial antagonism confers previously undescribed antibacterial capacity to eukaryotes. We speculate that the selective pressure imposed by competition between bacteria has produced a reservoir of genes encoding diverse antimicrobial functions that are tailored for co-option by eukaryotic innate immune systems.


Assuntos
Bactérias/enzimologia , Bactérias/genética , Toxinas Bacterianas/genética , Eucariotos/genética , Eucariotos/imunologia , Transferência Genética Horizontal/genética , Genes Bacterianos/genética , Imunidade Inata , Amidoidrolases/genética , Amidoidrolases/metabolismo , Animais , Bactérias/citologia , Bactérias/imunologia , Sistemas de Secreção Bacterianos , Toxinas Bacterianas/metabolismo , Borrelia burgdorferi/citologia , Borrelia burgdorferi/crescimento & desenvolvimento , Borrelia burgdorferi/imunologia , Parede Celular/metabolismo , Sequência Conservada/genética , Eucariotos/metabolismo , Imunidade Inata/genética , Ixodes/genética , Ixodes/imunologia , Ixodes/metabolismo , Ixodes/microbiologia , Filogenia , Especificidade por Substrato
15.
Eur J Appl Physiol ; 121(3): 839-848, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33386985

RESUMO

PURPOSE: Orthostatic hypotension, leading to cerebral hypoperfusion, can result in postural instability and falls in older adults. We determined the efficacy of a novel, intermittent pneumatic compression system, applying pressure around the lower legs, as a countermeasure against orthostatic stress in older adults. METHODS: Data were collected from 13 adults (4 male) over 65 years of age. Non-invasive ultrasound measured middle cerebral artery blood velocity (MCAv) and finger photoplethysmography measured mean arterial blood pressure (MAP). Intermittent lower leg compression was applied in a peristaltic manner in the local diastolic phase of each cardiac cycle to optimize venous return during 1-min of seated rest and during a sit-to-stand transition to 1-min of quiet standing with compression initiated 15 s before transition. RESULTS: During seated rest, compression resulted in a 4.5 ± 6.5 mmHg increase in MAP, and 2.3 ± 2.1 cm/s increase in MCAv (p < 0.05). MAP and MCAv increased during the 15 s of applied compression before the posture transition (2.3 ± 7.2 mmHg and 2.1 ± 4.0 cm/s, respectively, p < 0.05) with main effects for both variables confirming continued benefit during the transition and quiet stand periods. CONCLUSIONS: Application of carefully timed, intermittent compression to the lower legs of older adults increased MAP and MCAv during seated rest and maintained an elevated MAP and MCAv during a transition to standing posture. Future research could assess the benefits of this technology for persons at risk for orthostatic hypotension on standing and while walking in an effort to reduce injurious, unexplained falls in older adults.


Assuntos
Circulação Cerebrovascular/fisiologia , Perna (Membro)/irrigação sanguínea , Músculo Esquelético/irrigação sanguínea , Postura/fisiologia , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Masculino , Artéria Cerebral Média/fisiologia , Músculo Esquelético/fisiologia , Fotopletismografia , Fluxo Sanguíneo Regional , Posição Ortostática
16.
Proc Biol Sci ; 287(1931): 20200922, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-33043867

RESUMO

Most of the world's crops depend on pollinators, so declines in both managed and wild bees raise concerns about food security. However, the degree to which insect pollination is actually limiting current crop production is poorly understood, as is the role of wild species (as opposed to managed honeybees) in pollinating crops, particularly in intensive production areas. We established a nationwide study to assess the extent of pollinator limitation in seven crops at 131 locations situated across major crop-producing areas of the USA. We found that five out of seven crops showed evidence of pollinator limitation. Wild bees and honeybees provided comparable amounts of pollination for most crops, even in agriculturally intensive regions. We estimated the nationwide annual production value of wild pollinators to the seven crops we studied at over $1.5 billion; the value of wild bee pollination of all pollinator-dependent crops would be much greater. Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions.


Assuntos
Agricultura , Produtos Agrícolas , Polinização , Animais , Abelhas , Abastecimento de Alimentos , Estados Unidos
17.
J Antimicrob Chemother ; 75(12): 3485-3490, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830242

RESUMO

BACKGROUND: The incidence of antimicrobial-resistant Neisseria gonorrhoeae (GC) is rising in Canada; however, antimicrobial resistance (AMR) surveillance data are unavailable for infections diagnosed directly from clinical specimens by nucleic acid amplification tests (NAATs), representing over 80% of diagnoses. We developed a set of 10 improved molecular assays for surveillance of GC-AMR and prediction of susceptibilities in NAAT specimens. METHODS: Multiplex real-time PCR (RT-PCR) assays were developed to detect SNPs associated with cephalosporin (ponA, porB, mtrR -35delA, penA A311V, penA A501, N513Y, G545S), ciprofloxacin (gyrA S91, parC D86/S87/S88) and azithromycin [23S (A2059G, C2611T), mtrR meningitidis-like promoter] resistance. The assays were validated on 127 gonococcal isolates, 51 non-gonococcal isolates and 50 NAATs with matched culture isolates. SNPs determined from the assay were compared with SNPs determined from in silico analysis of WGS data. MICs were determined for culture isolates using the agar dilution method. RESULTS: SNP analysis of the 50 NAAT specimens had 96% agreement with the matched culture RT-PCR analysis. When compared with MICs, presence of penA A311V or penA A501 and two or more other SNPs correlated with decreased susceptibility and presence of three or more other SNPs correlated with intermediate susceptibility to cephalosporins; presence of any associated SNP correlated with ciprofloxacin or azithromycin resistance. NAAT-AMR predictions correlated with matched-culture cephalosporin, ciprofloxacin and azithromycin MICs at 94%, 100% and 98%, respectively. CONCLUSIONS: We expanded molecular tests for N. gonorrhoeae AMR prediction by adding new loci and multiplexing reactions to improve surveillance where culture isolates are unavailable.


Assuntos
Gonorreia , Neisseria gonorrhoeae , Antibacterianos/farmacologia , Azitromicina/farmacologia , Canadá , Cefalosporinas/farmacologia , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana , Neisseria gonorrhoeae/genética , Reação em Cadeia da Polimerase em Tempo Real
18.
Osteoporos Int ; 29(8): 1861-1874, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29869038

RESUMO

In spite of being a public health problem of pandemic proportions, osteoporosis continues to be underdiagnosed and undertreated especially in older adults with fragility fractures. Confirmation of this hypothesis resulted in the development of a novel Fracture Liaison Service (Rush FLS). Results of the first 12 months of operation revealed that patients with confirmed fragility fracture do not have a timely diagnosis at fracture occurrence or treatment of their disease. The Rush FLS is an effective fracture liaison model. INTRODUCTION: Determining the prevalence of undiagnosed and untreated osteoporosis in fragility fracture patients, either admitted to an academic tertiary care center or treated and discharged from the center's emergency department to be followed in the endocrinology bone clinic, using an innovative, educational, low-cost, physician-run Fracture Liaison Service (FLS). METHODS: An automated alert was integrated into the electronic medical record at Rush University Medical Center (RUMC), triggered by historical and/or acute fracture(s) in patients 50 years or older, in patients that were either admitted to the hospital or in patients evaluated in the emergency department and discharged to be followed in the endocrinology bone clinic. We report the results of the first 12 months of operation in patients admitted to the hospital. RESULTS: First acute fragility fracture(s) were identified in 36% (80/223), only historical fragility fracture(s) in 28% (63/223) and both acute and historical fragility fracture(s) in 36% (80/223). The cumulative subgroup with historical fragility fractures with/without new fractures included 67% (96/143) without a previous diagnosis of osteoporosis. First acute fragility fracture group included 83.8% (67/80) without a previous diagnosis of osteoporosis. Rush FLS "captured missed opportunities" in 73.1% (163/223) of previously undiagnosed and 77.1% (172/223) of previously untreated osteoporosis patients. Dual-energy x-ray absorptiometry (DXA) prior to FLS consult was confirmed in 30% (67/223). Vitamin D deficiency (25-hydroxy vitamin D < 20 ng/ml) in 41.9% (78/186) including undetectable levels in 16.6% (31/186) and secondary hyperparathyroidism in 43.3% (78/180) were the most common laboratory confirmed secondary etiologies for bone loss. CONCLUSIONS: This study reported undiagnosed, uninvestigated, and untreated osteoporosis in the majority of fragility fracture patients seen by the Rush FLS in the first 12 months of operation.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Atenção à Saúde/organização & administração , Osteoporose/diagnóstico , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Adulto , Idoso , Chicago , Estudos Transversais , Registros Eletrônicos de Saúde , Serviço Hospitalar de Emergência/organização & administração , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Equipe de Assistência ao Paciente/organização & administração , Prevenção Secundária/métodos , Prevenção Secundária/organização & administração
19.
J Clin Microbiol ; 55(3): 947-958, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28053212

RESUMO

A multilocus phylogenetic study was carried out to assess species identity of a set of 34 clinical isolates from Aspergillus section Circumdati from the United States and to determine their in vitro antifungal susceptibility against eight antifungal drugs. The genetic markers used were the internal transcribed spacer (ITS) region, and fragments of the beta-tubulin (BenA), calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2) genes. The drugs tested were amphotericin B, itraconazole, posaconazole, voriconazole, anidulafungin, caspofungin, micafungin, and terbinafine. The most common species sampled was A. westerdijkiae (29.4%), followed by a novel species, which was described here as A. pseudosclerotiorum (23.5%). Other species identified were A. sclerotiorum (17.6%), A. ochraceus (8.8%), A. subramanianii (8.8%), and A. insulicola and A. ochraceopetaliformis, with two isolates (5.9%) of each. The drugs that showed the most potent activity were caspofungin, micafungin, and terbinafine, while amphotericin B showed the least activity.


Assuntos
Antifúngicos/farmacologia , Aspergilose/microbiologia , Aspergillus/classificação , Aspergillus/efeitos dos fármacos , Filogenia , Aspergillus/genética , Aspergillus/isolamento & purificação , Calmodulina/genética , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Humanos , Testes de Sensibilidade Microbiana , RNA Polimerase II/genética , Análise de Sequência de DNA , Tubulina (Proteína)/genética , Estados Unidos
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