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1.
Health Expect ; 26(6): 2514-2524, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37602918

RESUMO

INTRODUCTION: Co-production is gaining increasing recognition as a good way of facilitating collaboration among different stakeholders, including members of the public. However, it remains an ambiguous concept as there is no definitive or universal model of co-production or clarity on what constitutes a good co-production approach. This paper draws on the reflections of the academic researchers, practitioners and public advisors involved in co-producing a priority-setting exercise. The exercise was conducted by the Primary and Community Health Services (PCHS) Theme of the National Institute for Health and Care Research Applied Research Collaboration for Kent, Surrey and Sussex (NIHR ARC KSS). METHODS: We collected data through written and verbal reflections from seven collaborators involved in the PCHS priority-setting exercise. We used Gibbs' model of reflection to guide the data collection. We then analysed the data through an inductive, reflexive thematic analysis. RESULTS: A common thread through our reflections was the concept of 'sharing'. Although co-production is inherently shared, we used the virtuous cycle to illustrate a sequence of sharing concepts during the research cycle, which provides the underpinnings of positive co-production outcomes. We identified six themes to denote the iterative process of a shared approach within the virtuous cycle: shared values, shared understanding, shared power, shared responsibilities, shared ownership and positive outcomes. CONCLUSION: Our results present a virtuous cycle of co-production, which furthers the conceptual underpinnings of co-production. Through our reflections, we propose that positive co-production outcomes require foundations of shared values and a shared understanding of co-production as a concept. These foundations facilitate a process of shared power, shared responsibilities and shared ownership. We argue that when these elements are present in a co-production exercise, there is a greater potential for implementable outcomes in the communities in which the research serves and the empowerment of collaborators involved in the co-production process. PUBLIC MEMBERS' CONTRIBUTIONS: Three members of the public who are public advisors in the NIHR ARC KSS were involved in the priority-setting exercise that informed this paper. The public advisors were involved in the design of the priority-setting exercise and supported participants' recruitment. They also co-facilitated the focus groups during data collection and were involved in the data analysis, interpretation and preparation of the priority-setting report. For this current manuscript, two of them are co-authors. They provided reflections and contributed to the writing and reviewing of this manuscript.


Assuntos
Empoderamento , Exercício Físico , Humanos , Grupos Focais
2.
BMC Microbiol ; 23(1): 97, 2023 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-37024800

RESUMO

Campylobacter species are the major cause of bacterial gastroenteritis. As there is no effective vaccine, combined with the rapid increase in antimicrobial resistant strains, there is a need to identify new targets for intervention. Essential genes are those that are necessary for growth and/or survival, making these attractive targets. In this study, comprehensive transposon mutant libraries were created in six C. jejuni strains, four C. coli strains and one C. lari and C. hyointestinalis strain, allowing for those genes that cannot tolerate a transposon insertion being called as essential. Comparison of essential gene lists using core genome analysis can highlight those genes which are common across multiple strains and/or species. Comparison of C. jejuni and C. coli, the two species that cause the most disease, identified 316 essential genes. Genes of interest highlighted members of the purine pathway being essential for C. jejuni whilst also finding that a functional potassium uptake system is essential. Protein-protein interaction networks using these essential gene lists also highlighted proteins in the purine pathway being major 'hub' proteins which have a large number of interactors across the network. When adding in two more species (C. lari and C. hyointestinalis) the essential gene list reduces to 261. Within these 261 essential genes, there are many genes that have been found to be essential in other bacteria. These include htrB and PEB4, which have previously been found as core virulence genes across Campylobacter species in other studies. There were 21 genes which have no known function with eight of these being associated with the membrane. These surface-associated essential genes may provide attractive targets. The essential gene lists presented will help to prioritise targets for the development of novel therapeutic and preventative interventions.


Assuntos
Infecções por Campylobacter , Campylobacter coli , Campylobacter jejuni , Campylobacter , Humanos , Campylobacter jejuni/genética , Campylobacter coli/genética , Infecções por Campylobacter/microbiologia
3.
Microbiome ; 9(1): 149, 2021 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-34183047

RESUMO

BACKGROUND: Since the prolonged use of insecticidal proteins has led to toxin resistance, it is important to search for novel insecticidal protein genes (IPGs) that are effective in controlling resistant insect populations. IPGs are usually encoded in the genomes of entomopathogenic bacteria, especially in large plasmids in strains of the ubiquitous soil bacteria, Bacillus thuringiensis (Bt). Since there are often multiple similar IPGs encoded by such plasmids, their assemblies are typically fragmented and many IPGs are scattered through multiple contigs. As a result, existing gene prediction tools (that analyze individual contigs) typically predict partial rather than complete IPGs, making it difficult to conduct downstream IPG engineering efforts in agricultural genomics. METHODS: Although it is difficult to assemble IPGs in a single contig, the structure of the genome assembly graph often provides clues on how to combine multiple contigs into segments encoding a single IPG. RESULTS: We describe ORFograph, a pipeline for predicting IPGs in assembly graphs, benchmark it on (meta)genomic datasets, and discover nearly a hundred novel IPGs. This work shows that graph-aware gene prediction tools enable the discovery of greater diversity of IPGs from (meta)genomes. CONCLUSIONS: We demonstrated that analysis of the assembly graphs reveals novel candidate IPGs. ORFograph identified both already known genes "hidden" in assembly graphs and potential novel IPGs that evaded existing tools for IPG identification. As ORFograph is fast, one could imagine a pipeline that processes many (meta)genomic assembly graphs to identify even more novel IPGs for phenotypic testing than would previously be inaccessible by traditional gene-finding methods. While here we demonstrated the results of ORFograph only for IPGs, the proposed approach can be generalized to any class of genes. Video abstract.


Assuntos
Inseticidas , Algoritmos , Genômica , Metagenoma , Metagenômica
4.
Appl Environ Microbiol ; 87(4)2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33310708

RESUMO

This study describes three closely related proteins, cloned from Brevibacillus laterosporus strains, that are lethal upon feeding to Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR). Mpp75Aa1, Mpp75Aa2 and Mpp75Aa3 were toxic to WCR larvae when fed purified protein. Transgenic plants expressing each mMpp75Aa protein were protected from feeding damage and showed significant reduction in adult emergence from infested plants by both susceptible and Cry3Bb1 and Cry34Ab1/Cry35Ab1-resistant WCR. These results demonstrate that proteins from B. laterosporus are as efficacious as the well-known Bacillus thuringiensis (Bt) insecticidal proteins in controlling major insect pests such as WCR. The deployment of transgenic maize expressing mMpp75Aa along with other active molecules lacking cross-resistance have the potential to be a useful tool for control of WCR populations resistant to current Bt traits.IMPORTANCE Insects feeding on roots of crops can damage the plant roots resulting in yield loss due to poor water and nutrient uptake and plant lodging. In maize the western corn rootworm (WCR) can cause severe damage to the roots resulting in significant economic loss for farmers. Genetically modified (GM) expressing Bacillus thuringiensis (Bt) insect control proteins, has provided a solution for control of these pests. In recent years populations of WCR resistant to the Bt proteins in commercial GM maize have emerged. There is a need to develop new insecticidal traits for the control of WCR populations resistant to current commercial traits. New proteins with commercial level efficacy on WCR from sources other than Bt are becoming more critical. The Mpp75Aa proteins, from B. laterosporus, when expressed in maize, are efficacious against the resistant populations of WCR and have the potential to provide solutions for control of resistant WCR.

5.
FEMS Microbiol Lett ; 367(22)2020 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-33186989

RESUMO

The use of bacterial transposon mutant libraries in phenotypic screens is a well-established technique for determining which genes are essential or advantageous for growth in conditions of interest. Standard, inactivating, transposon libraries cannot give direct information about genes whose over-expression gives a selective advantage. We report the development of a system wherein outward-oriented promoters are included in mini-transposons, generation of transposon mutant libraries in Escherichia coli and Pseudomonas aeruginosa and their use to probe genes important for growth under selection with the antimicrobial fosfomycin, and a recently-developed leucyl-tRNA synthase inhibitor. In addition to the identification of known mechanisms of action and resistance, we identify the carbon-phosphorous lyase complex as a potential resistance liability for fosfomycin in E. coli and P. aeruginosa. The use of this technology can facilitate the development of novel mechanism-of-action antimicrobials that are urgently required to combat the increasing threat worldwide from antimicrobial-resistant pathogenic bacteria.


Assuntos
Elementos de DNA Transponíveis/genética , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Regiões Promotoras Genéticas/genética , Pseudomonas aeruginosa/genética , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Biblioteca Gênica , Pseudomonas aeruginosa/efeitos dos fármacos
6.
Artigo em Inglês | MEDLINE | ID: mdl-31835832

RESUMO

Objectives: Fall preventive programs aim to reduce risks for mortality from fall-related injuries among older adults. However, the covariation between personal perceptions of falls and factors and confidence of self-management in falls (CSMoF) is still under-studied despite its importance to fall prevention. We aimed to investigate the relative contribution of CSMoF in relation to fall risk self-perceptions while controlling for demographics and self-reported health and functioning. Method: Participants were 691 older adults recruited from Area Agency on Aging at Arlington, Texas (females = 76.1%, mean age = 76.23, SD = 6.44, with chronic condition = 79.5%). They completed measures of physical functioning, CSMoF, fall risk perceptions and fear of falls. Results: Regression analyses indicated that fear of fall was the most predictive factor of CSMoF among older persons, accounting for about 25% of the variance. Physical function measures of age, chronic illnesses of metabolism, sensory impairment, and health status were also significant predictors of the CSMoF, but to a lesser extent than fear of falls and fall perceptions. The interaction of perception of falls and fall experience attenuated CSMoF, with physical functioning limitations. Conclusion: The joint effects of perception of falls and fear of falls likely explain CSMoF among older adults more than physical functional indicators. Fall prevention programs for older adults should prioritize to address modifiable subjective factors of fall perceptions, fear of falls, and CSMoF across health and functioning statuses.


Assuntos
Acidentes por Quedas/prevenção & controle , Autogestão/psicologia , Idoso , Idoso de 80 Anos ou mais , Medo , Feminino , Humanos , Masculino , Serviços Preventivos de Saúde , Análise de Regressão , Fatores de Risco , Autoimagem , Texas
7.
J Bacteriol ; 201(4)2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30510143

RESUMO

The outer membrane of Gram-negative bacteria presents a significant barrier for molecules entering the cell. Nevertheless, colicins, which are antimicrobial proteins secreted by Escherichia coli, can target other E. coli cells by binding to cell surface receptor proteins and activating their import, resulting in cell death. Previous studies have documented high rates of nonspecific resistance (insensitivity) of various E. coli strains toward colicins that is independent of colicin-specific immunity and is instead associated with lipopolysaccharide (LPS) in the outer membrane. This observation poses a contradiction: why do E. coli strains have colicin-expressing plasmids, which are energetically costly to retain, if cells around them are likely to be naturally insensitive to the colicin they produce? Here, using a combination of transposon sequencing and phenotypic microarrays, we show that colicin insensitivity of uropathogenic E. coli sequence type 131 (ST131) is dependent on the production of its O-antigen but that minor changes in growth conditions render the organism sensitive toward colicins. The reintroduction of O-antigen into E. coli K-12 demonstrated that it is the density of O-antigen that is the dominant factor governing colicin insensitivity. We also show, by microscopy of fluorescently labelled colicins, that growth conditions affect the degree of occlusion by O-antigen of outer membrane receptors but not the clustered organization of receptors. The result of our study demonstrate that environmental conditions play a critical role in sensitizing E. coli toward colicins and that O-antigen in LPS is central to this role.IMPORTANCEEscherichia coli infections can be a major health burden, especially with the organism becoming increasingly resistant to "last-resort" antibiotics such as carbapenems. Although colicins are potent narrow-spectrum antimicrobials with potential as future antibiotics, high levels of naturally occurring colicin insensitivity have been documented which could limit their efficacy. We identify O-antigen-dependent colicin insensitivity in a clinically relevant uropathogenic E. coli strain and show that this insensitivity can be circumvented by minor changes to growth conditions. The results of our study suggest that colicin insensitivity among E. coli organisms has been greatly overestimated, and as a consequence, colicins could in fact be effective species-specific antimicrobials targeting pathogenic E. coli such as uropathogenic E. coli (UPEC).


Assuntos
Antibacterianos/farmacologia , Colicinas/farmacologia , Farmacorresistência Bacteriana , Antígenos O/metabolismo , Escherichia coli Uropatogênica/efeitos dos fármacos , Elementos de DNA Transponíveis , Inativação Gênica , Metabolismo/efeitos dos fármacos , Análise em Microsséries , Testes de Sensibilidade Microbiana , Mutagênese Insercional , Antígenos O/genética , Fenótipo , Análise de Sequência de DNA , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Escherichia coli Uropatogênica/metabolismo
8.
mBio ; 9(1)2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29463657

RESUMO

Transposon-directed insertion site sequencing (TraDIS) is a high-throughput method coupling transposon mutagenesis with short-fragment DNA sequencing. It is commonly used to identify essential genes. Single gene deletion libraries are considered the gold standard for identifying essential genes. Currently, the TraDIS method has not been benchmarked against such libraries, and therefore, it remains unclear whether the two methodologies are comparable. To address this, a high-density transposon library was constructed in Escherichia coli K-12. Essential genes predicted from sequencing of this library were compared to existing essential gene databases. To decrease false-positive identification of essential genes, statistical data analysis included corrections for both gene length and genome length. Through this analysis, new essential genes and genes previously incorrectly designated essential were identified. We show that manual analysis of TraDIS data reveals novel features that would not have been detected by statistical analysis alone. Examples include short essential regions within genes, orientation-dependent effects, and fine-resolution identification of genome and protein features. Recognition of these insertion profiles in transposon mutagenesis data sets will assist genome annotation of less well characterized genomes and provides new insights into bacterial physiology and biochemistry.IMPORTANCE Incentives to define lists of genes that are essential for bacterial survival include the identification of potential targets for antibacterial drug development, genes required for rapid growth for exploitation in biotechnology, and discovery of new biochemical pathways. To identify essential genes in Escherichia coli, we constructed a transposon mutant library of unprecedented density. Initial automated analysis of the resulting data revealed many discrepancies compared to the literature. We now report more extensive statistical analysis supported by both literature searches and detailed inspection of high-density TraDIS sequencing data for each putative essential gene for the E. coli model laboratory organism. This paper is important because it provides a better understanding of the essential genes of E. coli, reveals the limitations of relying on automated analysis alone, and provides a new standard for the analysis of TraDIS data.


Assuntos
Escherichia coli K12/crescimento & desenvolvimento , Escherichia coli K12/genética , Genes Essenciais , Genoma Bacteriano , Biologia Molecular/métodos , Biologia Computacional , Elementos de DNA Transponíveis , Mutagênese Insercional , Análise de Sequência de DNA
10.
Microb Genom ; 3(11)2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29208119

RESUMO

Burkholderia cenocepacia K56-2 belongs to the Burkholderia cepacia complex, a group of Gram-negative opportunistic pathogens that have large and dynamic genomes. In this work, we identified the essential genome of B. cenocepacia K56-2 using high-density transposon mutagenesis and insertion site sequencing (Tn-seq circle). We constructed a library of one million transposon mutants and identified the transposon insertions at an average of one insertion per 27 bp. The probability of gene essentiality was determined by comparing of the insertion density per gene with the variance of neutral datasets generated by Monte Carlo simulations. Five hundred and eight genes were not significantly disrupted, suggesting that these genes are essential for survival in rich, undefined medium. Comparison of the B. cenocepacia K56-2 essential genome with that of the closely related B. cenocepacia J2315 revealed partial overlapping, suggesting that some essential genes are strain-specific. Furthermore, 158 essential genes were conserved in B. cenocepacia and two species belonging to the Burkholderia pseudomallei complex, B. pseudomallei K96243 and Burkholderia thailandensis E264. Porins, including OpcC, a lysophospholipid transporter, LplT, and a protein involved in the modification of lipid A with aminoarabinose were found to be essential in Burkholderia genomes but not in other bacterial essential genomes identified so far. Our results highlight the existence of cell envelope processes that are uniquely essential in species of the genus Burkholderia for which the essential genomes have been identified by Tn-seq.


Assuntos
Infecções por Burkholderia/microbiologia , Burkholderia cenocepacia/genética , Farmacorresistência Bacteriana/genética , Genoma Bacteriano , Burkholderia cenocepacia/citologia , Burkholderia cenocepacia/metabolismo , Burkholderia cenocepacia/patogenicidade , Biblioteca Gênica , Genes Essenciais , Genômica , Mutagênese , Análise de Sequência de DNA
11.
mBio ; 8(2)2017 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-28292986

RESUMO

Environmental conditions affect bacterial behavior and can greatly influence the course of an infection. However, the environmental cues that elicit bacterial responses in specific infection sites are relatively unknown. Pseudomonas aeruginosa is ubiquitous in nature and typically innocuous. However, it is also one of the most prevalent causes of fatal sepsis in burn wound patients. The aim of this study was to determine the impact of environmental factors, specifically the availability of arginine, on the pathogenesis of P. aeruginosa in burn wound infections. Comparison of burned versus noninjured tissue revealed that l-arginine (l-Arg) was significantly depleted in burn wounds as a consequence of elevated arginase produced by myeloid-derived suppressor cells. We also observed that l-Arg was a potent chemoattractant for P. aeruginosa, and while low concentrations of l-Arg increased P. aeruginosa's swimming motility, high concentrations resulted in diminished swimming. Based on these observations, we tested whether the administration of exogenous l-Arg into the burn wound could attenuate the virulence of P. aeruginosa in thermally injured mice. Administration of l-Arg resulted in decreased P. aeruginosa spread and sepsis and increased animal survival. Taken together, these data demonstrate that the availability of environmental arginine greatly influences the virulence of P. aeruginosa in vivo and may represent a promising phenotype-modulating tool for future therapeutic avenues.IMPORTANCE Despite our growing understanding of the pathophysiology of burn wounds and the evolution of techniques and practices to manage infections, sepsis remains a significant medical concern for burn patients. P. aeruginosa continues to be a leader among all causes of bacteremic infections due to its tendency to cause complications in immunocompromised patients and its ubiquitous presence in the hospital setting. With the unforgiving emergence of multidrug-resistant strains, it is critical that alternative strategies to control or prevent septic infections in burn patients be developed in parallel with novel antimicrobial agents. In this study, we observed that administration of l-Arg significantly reduced bacterial spread and sepsis in burned mice infected with P. aeruginosa Given the safety of l-Arg in high doses and its potential wound-healing benefits, this conditionally essential amino acid may represent a useful tool to modulate bacterial behavior in vivo and prevent sepsis in burn patients.


Assuntos
Arginina/metabolismo , Queimaduras/complicações , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/metabolismo , Infecção dos Ferimentos/microbiologia , Animais , Antibacterianos/administração & dosagem , Antibacterianos/metabolismo , Arginina/administração & dosagem , Modelos Animais de Doenças , Camundongos , Infecções por Pseudomonas/tratamento farmacológico , Análise de Sobrevida , Resultado do Tratamento , Virulência , Infecção dos Ferimentos/tratamento farmacológico
12.
Soc Work Public Health ; 31(5): 439-52, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27191952

RESUMO

Healthy diet and weight control are important for elders and senior centers (SCs). The authors consider effects of SCs on attendee nutrition and health and efforts to improve diets and weight. Data derive from surveys in 2006 (N = 798) and 2007 (N = 742) at 21 multipurpose SCs in Tarrant County, Texas, supplemented with data from 2012 (N = 1,402). Measures included attendee agreement that SC meals improved nutrition, improved health, attempts to improve diets, and success in controlling weight. Cumulative and binary logistic regression methods were employed. SC attendance and social engagement explained agreement that SC meals improved nutrition and health but were not shown to predict changes in diet or weight control. Findings suggest success of SC programs, as well as physician recommendations, in influencing attendee nutritional behavior and perceptions of nutrition and health effects. Practice recommendations include SC collaborations with local health providers to promote attendee nutritional health.


Assuntos
Estado Nutricional , Centros Comunitários para Idosos , Idoso , Estudos Transversais , Dieta , Feminino , Nível de Saúde , Humanos , Masculino , Razão de Chances , Inquéritos e Questionários , Texas
13.
Nature ; 533(7601): 58-63, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27120167

RESUMO

The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd = 11-41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects.


Assuntos
Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Evolução Molecular Direcionada/métodos , Endotoxinas/genética , Endotoxinas/metabolismo , Variação Genética/genética , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Resistência a Inseticidas , Mariposas/fisiologia , Controle Biológico de Vetores/métodos , Sequência de Aminoácidos , Animais , Toxinas de Bacillus thuringiensis , Bacteriófagos/genética , Biotecnologia , Caderinas/metabolismo , Morte Celular , Sequência Consenso , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Inseticidas/metabolismo , Dados de Sequência Molecular , Mariposas/citologia , Mutagênese/genética , Plantas Geneticamente Modificadas , Ligação Proteica/genética , Estabilidade Proteica , Seleção Genética
14.
Soc Work Public Health ; 30(3): 236-49, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25751585

RESUMO

This article aims to determine how various health insurance policies affect the rate of emergency room (ER) referrals in the United States. The secondary data, gathered in National Health Measurement Study (NHMS) in 2008 and 2010, was used. The authors identify the relationships between health insurance and ER referrals by using zero-inflated binomial and zero-inflated Poisson regression. About 17% (2008) and 20% (2010) of the respondents had one or more ER referrals in the 2 years; those who were under coverage of governmental health insurance are more likely to refer ER than uninsured group. The differences in ER referrals that ended with hospital admission across different insurance policies are not significant. Health insurance is a remarkable factor in ER referrals; the coverage of health insurance plans can affect consuming the services provided in ER. Governmental insurance plans can increase ER referrals.


Assuntos
Serviço Hospitalar de Emergência , Cobertura do Seguro , Seguro Saúde , Encaminhamento e Consulta/estatística & dados numéricos , Feminino , Pesquisas sobre Atenção à Saúde , Humanos , Entrevistas como Assunto , Masculino , Pesquisa Qualitativa , Estados Unidos
15.
Proc Natl Acad Sci U S A ; 112(13): 4110-5, 2015 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-25775563

RESUMO

Defining the essential genome of bacterial pathogens is central to developing an understanding of the biological processes controlling disease. This has proven elusive for Pseudomonas aeruginosa during chronic infection of the cystic fibrosis (CF) lung. In this paper, using a Monte Carlo simulation-based method to analyze high-throughput transposon sequencing data, we establish the P. aeruginosa essential genome with statistical precision in laboratory media and CF sputum. Reconstruction of the global requirements for growth in CF sputum compared with defined growth conditions shows that the latter requires several cofactors including biotin, riboflavin, and pantothenate. Comparison of P. aeruginosa strains PAO1 and PA14 demonstrates that essential genes are primarily restricted to the core genome; however, some orthologous genes in these strains exhibit differential essentiality. These results indicate that genes with similar molecular functions may have distinct genetic roles in different P. aeruginosa strains during growth in CF sputum. We also show that growth in a defined growth medium developed to mimic CF sputum yielded virtually identical fitness requirements to CF sputum, providing support for this medium as a relevant in vitro model for CF microbiology studies.


Assuntos
Fibrose Cística/microbiologia , Genoma Bacteriano , Pseudomonas aeruginosa/genética , Escarro/microbiologia , Biotina/química , Simulação por Computador , Humanos , Pulmão/microbiologia , Método de Monte Carlo , Ácido Pantotênico/química , Reação em Cadeia da Polimerase , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/classificação , Riboflavina/química , Especificidade da Espécie , Células-Tronco , Ferimentos e Lesões/microbiologia
17.
PLoS Genet ; 10(7): e1004518, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25057820

RESUMO

Opportunistic infections caused by Pseudomonas aeruginosa can be acute or chronic. While acute infections often spread rapidly and can cause tissue damage and sepsis with high mortality rates, chronic infections can persist for weeks, months, or years in the face of intensive clinical intervention. Remarkably, this diverse infectious capability is not accompanied by extensive variation in genomic content, suggesting that the genetic capacity to be an acute or a chronic pathogen is present in most P. aeruginosa strains. To investigate the genetic requirements for acute and chronic pathogenesis in P. aeruginosa infections, we combined high-throughput sequencing-mediated transcriptome profiling (RNA-seq) and genome-wide insertion mutant fitness profiling (Tn-seq) to characterize gene expression and fitness determinants in murine models of burn and non-diabetic chronic wound infection. Generally we discovered that expression of a gene in vivo is not correlated with its importance for fitness, with the exception of metabolic genes. By combining metabolic models generated from in vivo gene expression data with mutant fitness profiles, we determined the nutritional requirements for colonization and persistence in these infections. Specifically, we found that long-chain fatty acids represent a major carbon source in both chronic and acute wounds, and P. aeruginosa must biosynthesize purines, several amino acids, and most cofactors during infection. In addition, we determined that P. aeruginosa requires chemotactic flagellar motility for fitness and virulence in acute burn wound infections, but not in non-diabetic chronic wound infections. Our results provide novel insight into the genetic requirements for acute and chronic P. aeruginosa wound infections and demonstrate the power of using both gene expression and fitness profiling for probing bacterial virulence.


Assuntos
Lesões Encefálicas/genética , Perfilação da Expressão Gênica , Pseudomonas aeruginosa/genética , Infecção da Ferida Cirúrgica/genética , Animais , Lesões Encefálicas/microbiologia , Modelos Animais de Doenças , Regulação Bacteriana da Expressão Gênica , Aptidão Genética , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Patógeno/genética , Humanos , Camundongos , Infecções Oportunistas/genética , Infecções Oportunistas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Infecção da Ferida Cirúrgica/microbiologia , Fatores de Virulência/genética
18.
mBio ; 5(2): e01012-14, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24692635

RESUMO

The human microbiome plays important roles in health, but when disrupted, these same indigenous microbes can cause disease. The composition of the microbiome changes during the transition from health to disease; however, these changes are often not conserved among patients. Since microbiome-associated diseases like periodontitis cause similar patient symptoms despite interpatient variability in microbial community composition, we hypothesized that human-associated microbial communities undergo conserved changes in metabolism during disease. Here, we used patient-matched healthy and diseased samples to compare gene expression of 160,000 genes in healthy and diseased periodontal communities. We show that health- and disease-associated communities exhibit defined differences in metabolism that are conserved between patients. In contrast, the metabolic gene expression of individual species was highly variable between patients. These results demonstrate that despite high interpatient variability in microbial composition, disease-associated communities display conserved metabolic profiles that are generally accomplished by a patient-specific cohort of microbes. IMPORTANCE The human microbiome project has shown that shifts in our microbiota are associated with many diseases, including obesity, Crohn's disease, diabetes, and periodontitis. While changes in microbial populations are apparent during these diseases, the species associated with each disease can vary from patient to patient. Taking into account this interpatient variability, we hypothesized that specific microbiota-associated diseases would be marked by conserved microbial community behaviors. Here, we use gene expression analyses of patient-matched healthy and diseased human periodontal plaque to show that microbial communities have highly conserved metabolic gene expression profiles, whereas individual species within the community do not. Furthermore, disease-associated communities exhibit conserved changes in metabolic and virulence gene expression.


Assuntos
Metagenoma , Microbiota , Boca/microbiologia , Transcriptoma , Adulto , Disbiose , Feminino , Humanos , Masculino , Periodontite/microbiologia
19.
J Microbiol ; 52(3): 188-99, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24585050

RESUMO

Communities of microbes can live almost anywhere and contain many different species. Interactions between members of these communities often determine the state of the habitat in which they live. When these habitats include sites on the human body, these interactions can affect health and disease. Polymicrobial synergy can occur during infection, in which the combined effect of two or more microbes on disease is worse than seen with any of the individuals alone. Powerful genomic methods are increasingly used to study microbial communities, including metagenomics to reveal the members and genetic content of a community and metatranscriptomics to describe the activities of community members. Recent efforts focused toward a mechanistic understanding of these interactions have led to a better appreciation of the precise bases of polymicrobial synergy in communities containing bacteria, eukaryotic microbes, and/or viruses. These studies have benefited from advances in the development of in vivo models of polymicrobial infection and modern techniques to profile the spatial and chemical bases of intermicrobial communication. This review describes the breadth of mechanisms microbes use to interact in ways that impact pathogenesis and techniques to study polymicrobial communities.


Assuntos
Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/microbiologia , Fenômenos Fisiológicos Bacterianos , Coinfecção/microbiologia , Interações Microbianas , Animais , Interações Hospedeiro-Patógeno , Humanos
20.
Nucleic Acids Res ; 42(2): 979-98, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24157832

RESUMO

Pathogenicity of Pseudomonas aeruginosa, a major cause of many acute and chronic human infections, is determined by tightly regulated expression of multiple virulence factors. Quorum sensing (QS) controls expression of many of these pathogenic determinants. Previous microarray studies have shown that the AmpC ß-lactamase regulator AmpR, a member of the LysR family of transcription factors, also controls non-ß-lactam resistance and multiple virulence mechanisms. Using RNA-Seq and complementary assays, this study further expands the AmpR regulon to include diverse processes such as oxidative stress, heat shock and iron uptake. Importantly, AmpR affects many of these phenotypes, in part, by regulating expression of non-coding RNAs such as rgP32, asRgsA, asPrrF1 and rgRsmZ. AmpR positively regulates expression of the major QS regulators LasR, RhlR and MvfR, and genes of the Pseudomonas quinolone system. Chromatin immunoprecipitation (ChIP)-Seq and ChIP-quantitative real-time polymerase chain reaction studies show that AmpR binds to the ampC promoter both in the absence and presence of ß-lactams. In addition, AmpR directly binds the lasR promoter, encoding the QS master regulator. Comparison of the AmpR-binding sequences from the transcriptome and ChIP-Seq analyses identified an AT-rich consensus-binding motif. This study further attests to the role of AmpR in regulating virulence and physiological processes in P. aeruginosa.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Pseudomonas aeruginosa/genética , Pequeno RNA não Traduzido/metabolismo , Regulon , Fatores de Transcrição/metabolismo , Proteínas de Bactérias/genética , Perfilação da Expressão Gênica , Resposta ao Choque Térmico/genética , Sequenciamento de Nucleotídeos em Larga Escala , Ferro/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Óperon , Estresse Oxidativo/genética , Fenazinas/metabolismo , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Percepção de Quorum , Análise de Sequência de RNA , Transativadores/genética
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