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1.
Cell ; 166(3): 582-595, 2016 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-27426947

RESUMO

APS1/APECED patients are defined by defects in the autoimmune regulator (AIRE) that mediates central T cell tolerance to many self-antigens. AIRE deficiency also affects B cell tolerance, but this is incompletely understood. Here we show that most APS1/APECED patients displayed B cell autoreactivity toward unique sets of approximately 100 self-proteins. Thereby, autoantibodies from 81 patients collectively detected many thousands of human proteins. The loss of B cell tolerance seemingly occurred during antibody affinity maturation, an obligatorily T cell-dependent step. Consistent with this, many APS1/APECED patients harbored extremely high-affinity, neutralizing autoantibodies, particularly against specific cytokines. Such antibodies were biologically active in vitro and in vivo, and those neutralizing type I interferons (IFNs) showed a striking inverse correlation with type I diabetes, not shown by other anti-cytokine antibodies. Thus, naturally occurring human autoantibodies may actively limit disease and be of therapeutic utility.


Assuntos
Afinidade de Anticorpos , Autoanticorpos/imunologia , Resistência à Doença/imunologia , Poliendocrinopatias Autoimunes/imunologia , Fatores de Transcrição/deficiência , Adolescente , Adulto , Idoso , Animais , Anticorpos Neutralizantes/imunologia , Criança , Pré-Escolar , Citocinas/imunologia , Diabetes Mellitus Tipo 1/imunologia , Humanos , Tolerância Imunológica , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Linfócitos T/imunologia , Adulto Jovem , Proteína AIRE
2.
Arch Microbiol ; 204(5): 253, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35412092

RESUMO

Poultry provides an important protein source consumed globally by human population, and simultaneously, acts as a substantial reservoir of antibiotic resistant bacterial species such as Escherichia coli, Salmonella, Campylobacter, Clostridium perfringens. These bacterial species can include commensal strains with beneficial roles on poultry health and productivity, and pathogenic strains not only to poultry but zoonotically to man. This review paper evaluates the role of phytochemicals as possible alternatives to antibiotics and natural anti-bacterial agents to control antibiotic resistance in poultry. The focus of this paper is on the polyphenolic phytochemicals as they constitute the major group; carvacrol oil (the active ingredient of oregano), thymol oil (the main ingredient of oregano), oregano oil, and tannins oil as feed additives and their mechanism of actions that might enhance avian gut health by controlling antibiotic-resistant bacterial strains spread in poultry.


Assuntos
Galinhas , Infecções por Escherichia coli , Animais , Antibacterianos/farmacologia , Bactérias , Galinhas/microbiologia , Farmacorresistência Bacteriana , Escherichia coli , Infecções por Escherichia coli/microbiologia , Humanos , Compostos Fitoquímicos/farmacologia , Aves Domésticas/microbiologia
3.
Arch Microbiol ; 203(4): 1555-1563, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33399894

RESUMO

Two different types of condensed tannins (CTs), which were extracted and purified from tilia (Tilia L.) and black locust (Robinia pseudoacacia), were studied and tested against two kinds of bacteria, including Gram-negative and Gram-positive, avian pathogenic E. coli (APEC) and Staphylococcus epidermidis (S. epidermidis) respectively, by minimal bactericidal concentrations (MBCs) and scanning electron microscopy (SEM). Both CT extracts were significantly effective (p ≤ 0.05) at MBCs of 5-10 mg CT/ml against APEC (Gram-negative), and at 1.25-5 mg CT/ml on S. epidermidis (Gram-positive). This indicated that the CTs were more potent against the Gram-positive than the Gram-negative bacteria. Further, SEM revealed that CTs caused mainly morphological deformations of the bacterial cells and some conjoined cell growth.


Assuntos
Escherichia coli , Microscopia Eletrônica de Varredura , Extratos Vegetais , Proantocianidinas , Robinia , Staphylococcus epidermidis , Tilia , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Proantocianidinas/isolamento & purificação , Proantocianidinas/farmacologia , Robinia/química , Staphylococcus epidermidis/efeitos dos fármacos , Tilia/química
4.
Proc Natl Acad Sci U S A ; 115(5): 1039-1044, 2018 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-29339503

RESUMO

The long-held view that gamma delta (γδ) T cells in mice and humans are fundamentally dissimilar, as are γδ cells in blood and peripheral tissues, has been challenged by emerging evidence of the cells' regulation by butyrophilin (BTN) and butyrophilin-like (BTNL) molecules. Thus, murine Btnl1 and the related gene, Skint1, mediate T cell receptor (TCR)-dependent selection of murine intraepithelial γδ T cell repertoires in gut and skin, respectively; BTNL3 and BTNL8 are TCR-dependent regulators of human gut γδ cells; and BTN3A1 is essential for TCR-dependent activation of human peripheral blood Vγ9Vδ2+ T cells. However, some observations concerning BTN/Btnl molecules continue to question the extent of mechanistic conservation. In particular, murine and human gut γδ cell regulation depends on pairings of Btnl1 and Btnl6 and BTNL3 and BTNL8, respectively, whereas blood γδ cells are reported to be regulated by BTN3A1 independent of other BTNs. Addressing this paradox, we show that BTN3A2 regulates the subcellular localization of BTN3A1, including functionally important associations with the endoplasmic reticulum (ER), and is specifically required for optimal BTN3A1-mediated activation of Vγ9Vδ2+ T cells. Evidence that BTNL3/BTNL8 and Btnl1/Btnl6 likewise associate with the ER reinforces the prospect of broadly conserved mechanisms underpinning the selection and activation of γδ cells in mice and humans, and in blood and extralymphoid sites.


Assuntos
Butirofilinas/imunologia , Butirofilinas/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Motivos de Aminoácidos , Animais , Antígenos CD/química , Antígenos CD/imunologia , Antígenos CD/metabolismo , Butirofilinas/química , Retículo Endoplasmático/imunologia , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Ativação Linfocitária , Camundongos , Multimerização Proteica
5.
Molecules ; 25(16)2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32824081

RESUMO

In this study, we tested the growth inhibition effect of 22 individual ellagitannins and of pentagalloylglucose on four bacterial species, i.e., Clostridiales perfringens, Escherichia coli, Lactobacillus plantarum and Staphylococcus aureus. All tested compounds showed antimicrobial effects against S. aureus, and almost all against E. coli and C. perfringens. For L. plantarum, no or very weak growth inhibition was detected. The level of inhibition was the greatest for S. aureus and the weakest for C. perfringens. For S. aureus, the molecular size or flexibility of ellagitannins did not show a clear relationship with their antimicrobial activity, even though rugosins E and D and pentagalloylglucose with four or five free galloyl groups had a stronger growth inhibition effect than the other ellagitannins with glucopyranose cores but with less free galloyl groups. Additionally, our results with S. aureus showed that the oligomeric linkage of ellagitannin might have an effect on its antimicrobial activity. For E. coli, the molecular size, but not the molecular flexibility, of ellagitannins seemed to be an important factor. For C. perfringens, both the molecular size and the flexibility of ellagitannin were important factors. In previous studies, corilagin was used as a model for ellagitannins, but our results showed that other ellagitannins are much more efficacious; therefore, the antimicrobial effects of ellagitannins could be more significant than previously thought.


Assuntos
Antibacterianos/farmacologia , Clostridiales/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Taninos Hidrolisáveis/farmacologia , Lactobacillus plantarum/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Clostridiales/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Lactobacillus plantarum/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
6.
BMC Microbiol ; 19(1): 294, 2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842755

RESUMO

BACKGROUND: Thymol is a phenolic compound used for its wide spectrum antimicrobial activity. There is a limited understanding of the antimicrobial mechanisms underlying thymol activity. To investigate this, E. coli strain JM109 was exposed to thymol at sub-lethal concentrations and after 16 rounds of exposure, isolates with a 2-fold increased minimal inhibitory concentration (MIC) were recovered (JM109-Thyr). The phenotype was stable after multiple sub-cultures without thymol. RESULTS: Cell morphology studies by scanning electron microscopy (SEM) suggest that thymol renders bacterial cell membranes permeable and disrupts cellular integrity. 1H Nuclear magnetic resonance (NMR) data showed an increase in lactate and the lactic acid family amino acids in the wild type and JM109-Thyr in the presence of thymol, indicating a shift from aerobic respiration to fermentation. Sequencing of JM109-Thyr defined multiple mutations including a stop mutation in the acrR gene resulting in a truncation of the repressor of the AcrAB efflux pump. AcrAB is a multiprotein complex traversing the cytoplasmic and outer membrane, and is involved in antibiotic clearance. CONCLUSIONS: Our data suggests that thymol tolerance in E. coli induces morphological, metabolic and genetic changes to adapt to thymol antimicrobial activity.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Timol/farmacologia , Permeabilidade da Membrana Celular , Farmacorresistência Bacteriana Múltipla , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Fermentação , Regulação Bacteriana da Expressão Gênica , Lactatos/metabolismo , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana , Mutação , Fenótipo , Proteínas Repressoras/genética
7.
BMC Vet Res ; 15(1): 37, 2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-30683093

RESUMO

BACKGROUND: Infection of the digestive track by gastro-intestinal pathogens results in the development of symptoms ranging from mild diarrhea to more severe clinical signs such as dysentery, severe dehydration and potentially death. Although, antibiotics are efficient to tackle infections, they also trigger dysbiosis that has been suggested to result in variation in weight gain in animal production systems. RESULTS: Here is the first study demonstrating the metabolic impact of infection by a gastro-intestinal pathogen (Brachyspira pilosicoli) and its resolution by antibiotic treatment (tiamulin) on the host (chicken) systemic metabolism and gut microbiota composition using high-resolution 1H nuclear magnetic resonance (NMR) spectroscopy and 16S rDNA next generation sequencing (NGS). Clear systemic metabolic markers of infections such as glycerol and betaine were identified. Weight loss in untreated animals was in part explained by the observation of a modification of systemic host energy metabolism characterized by the utilization of glycerol as a glucose precursor. However, antibiotic treatment triggered an increased VLDL/HDL ratio in plasma that may contribute to reducing weight loss observed in treated birds. All metabolic responses co-occurred with significant shift of the microbiota upon infection or antibiotic treatment. CONCLUSION: This study indicates that infection and antibiotic treatment trigger dysbiosis that may impact host systemic energy metabolism and cause phenotypic and health modifications.


Assuntos
Disbiose/induzido quimicamente , Gastroenteropatias/veterinária , Microbioma Gastrointestinal/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/veterinária , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Peso Corporal/efeitos dos fármacos , Brachyspira , Galinhas , Modelos Animais de Doenças , Diterpenos/farmacologia , Diterpenos/uso terapêutico , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/metabolismo , Gastroenteropatias/microbiologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico
8.
J Biol Chem ; 291(17): 9310-21, 2016 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-26917727

RESUMO

Dendritic epidermal T cells (DETC) form a skin-resident γδ T cell population that makes key contributions to cutaneous immune stress surveillance, including non-redundant contributions to protection from cutaneous carcinogens. How DETC become uniquely associated with the epidermis was in large part solved by the identification of Skint-1, the prototypic member of a novel B7-related multigene family. Expressed only by thymic epithelial cells and epidermal keratinocytes, Skint-1 drives specifically the development of DETC progenitors, making it the first clear candidate for a selecting ligand for non-MHC/CD1-restricted T cells. However, the molecular mechanisms underpinning Skint-1 activity are unresolved. Here, we provide evidence that DETC selection requires Skint-1 expression on the surface of thymic epithelial cells, and depends upon specific residues on the CDR3-like loop within the membrane-distal variable domain of Skint-1 (Skint-1 DV). Nuclear magnetic resonance of Skint-1 DV revealed a core tertiary structure conserved across the Skint family, but a highly distinct surface charge distribution, possibly explaining its unique function. Crucially, the CDR3-like loop formed an electrostatically distinct surface, featuring key charged and hydrophobic solvent-exposed residues, at the membrane-distal tip of DV. These results provide the first structural insights into the Skint family, identifying a putative receptor binding surface that directly implicates Skint-1 in receptor-ligand interactions crucial for DETC selection.


Assuntos
Epiderme/imunologia , Células Epiteliais/imunologia , Imunoglobulinas/química , Imunoglobulinas/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Linfócitos T/imunologia , Animais , Linhagem Celular , Humanos , Camundongos , Ressonância Magnética Nuclear Biomolecular , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína
9.
Anaerobe ; 45: 71-77, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28373121

RESUMO

Pathogenic anaerobes Brachyspira spp. are responsible for an increasing number of Intestinal Spirochaetosis (IS) cases in livestock against which few approved treatments are available. Tiamulin is used to treat swine dysentery caused by Brachyspira spp. and recently has been used to handle avian intestinal spirochaetosis (AIS). The therapeutic dose used in chickens requires further evaluation since cases of bacterial resistance to tiamulin have been reported. In this study, we evaluated the impact of tiamulin at varying concentrations on the metabolism of B. pilosicoli using a 1H-NMR-based metabonomics approach allowing the capture of the overall bacterial metabolic response to antibiotic treatment. Based on growth curve studies, tiamulin impacted bacterial growth even at very low concentration (0.008 µg/mL) although its metabolic activity was barely affected 72 h post exposure to antibiotic treatment. Only the highest dose of tiamulin tested (0.250 µg/mL) caused a major metabolic shift. Results showed that below this concentration, bacteria could maintain a normal metabolic trajectory despite significant growth inhibition by the antibiotic, which may contribute to disease reemergence post antibiotic treatment. Indeed, we confirmed that B. pilosicoli remained viable even after exposition to the highest antibiotic dose. This paper stresses the need to ensure new evaluation of bacterial viability post bacteriostatic exposure such as tiamulin to guarantee treatment efficacy and decrease antibiotic resistance development.


Assuntos
Antibacterianos/farmacologia , Brachyspira/química , Brachyspira/efeitos dos fármacos , Metabolômica , Brachyspira/crescimento & desenvolvimento , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética
10.
BMC Genomics ; 17(1): 960, 2016 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-27875980

RESUMO

BACKGROUND: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, which results in significant economic losses to the poultry industry worldwide. However, the diversity between isolates remains poorly understood. Here, a total of 272 APEC isolates collected from the United Kingdom (UK), Italy and Germany were characterised using multiplex polymerase chain reactions (PCRs) targeting 22 equally weighted factors covering virulence genes, R-type and phylogroup. Following these analysis, 95 of the selected strains were further analysed using Whole Genome Sequencing (WGS). RESULTS: The most prevalent phylogroups were B2 (47%) and A1 (22%), although there were national differences with Germany presenting group B2 (35.3%), Italy presenting group A1 (53.3%) and UK presenting group B2 (56.1%) as the most prevalent. R-type R1 was the most frequent type (55%) among APEC, but multiple R-types were also frequent (26.8%). Following compilation of all the PCR data which covered a total of 15 virulence genes, it was possible to build a similarity tree using each PCR result unweighted to produce 9 distinct groups. The average number of virulence genes was 6-8 per isolate, but no positive association was found between phylogroup and number or type of virulence genes. A total of 95 isolates representing each of these 9 groupings were genome sequenced and analysed for in silico serotype, Multilocus Sequence Typing (MLST), and antimicrobial resistance (AMR). The UK isolates showed the greatest variability in terms of serotype and MLST compared with German and Italian isolates, whereas the lowest prevalence of AMR was found for German isolates. Similarity trees were compiled using sequencing data and notably single nucleotide polymorphism data generated ten distinct geno-groups. The frequency of geno-groups across Europe comprised 26.3% belonging to Group 8 representing serogroups O2, O4, O18 and MLST types ST95, ST140, ST141, ST428, ST1618 and others, 18.9% belonging to Group 1 (serogroups O78 and MLST types ST23, ST2230), 15.8% belonging to Group 10 (serogroups O8, O45, O91, O125ab and variable MLST types), 14.7% belonging to Group 7 (serogroups O4, O24, O35, O53, O161 and MLST type ST117) and 13.7% belonging to Group 9 (serogroups O1, O16, O181 and others and MLST types ST10, ST48 and others). The other groups (2, 3, 4, 5 and 6) each contained relatively few strains. However, for some of the genogroups (e.g. groups 6 and 7) partial overlap with SNPs grouping and PCR grouping (matching PCR groups 8 (13 isolates on 22) and 1 (14 isolates on 16) were observable). However, it was not possible to obtain a clear correlation between genogroups and unweighted PCR groupings. This may be due to the genome plasticity of E. coli that enables strains to carry the same virulence factors even if the overall genotype is substantially different. CONCLUSIONS: The conclusion to be drawn from the lack of correlations is that firstly, APEC are very diverse and secondly, it is not possible to rely on any one or more basic molecular or phenotypic tests to define APEC with clarity, reaffirming the need for whole genome analysis approaches which we describe here. This study highlights the presence of previously unreported serotypes and MLSTs for APEC in Europe. Moreover, it is a first step on a cautious reconsideration of the merits of classical identification criteria such as R typing, phylogrouping and serotyping.


Assuntos
Infecções por Escherichia coli/veterinária , Escherichia coli/genética , Genoma Bacteriano , Genômica , Doenças das Aves Domésticas/microbiologia , Animais , Análise por Conglomerados , Biologia Computacional/métodos , Mineração de Dados , Farmacorresistência Bacteriana , Escherichia coli/classificação , Escherichia coli/efeitos dos fármacos , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Aprendizado de Máquina , Tipagem de Sequências Multilocus , Filogenia , Polimorfismo de Nucleotídeo Único , Sorotipagem , Fatores de Virulência/genética
11.
J Antimicrob Chemother ; 71(5): 1178-82, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26803720

RESUMO

OBJECTIVES: This study aimed to compare ESBL-producing Escherichia coli causing infections in humans with infecting or commensal isolates from animals and isolates from food of animal origin in terms of the strain types, the ESBL gene present and the plasmids that carry the respective ESBL genes. METHODS: A collection of 353 ESBL-positive E. coli isolates from the UK, the Netherlands and Germany were studied by MLST and ESBL genes were identified. Characterization of ESBL gene-carrying plasmids was performed using PCR-based replicon typing. Moreover, IncI1-Iγ and IncN plasmids were characterized by plasmid MLST. RESULTS: The ESBL-producing E. coli represented 158 different STs with ST131, ST10 and ST88 being the most common. Overall, blaCTX-M-1 was the most frequently detected ESBL gene, followed by blaCTX-M-15, which was the most common ESBL gene in the human isolates. The most common plasmid replicon type overall was IncI1-Iγ followed by multiple IncF replicons. CONCLUSIONS: ESBL genes were present in a wide variety of E. coli STs. IncI1-Iγ plasmids that carried the blaCTX-M-1 gene were widely disseminated amongst STs in isolates from animals and humans, whereas other plasmids and STs appeared to be more restricted to isolates from specific hosts.


Assuntos
Toxinas Bacterianas/genética , Enterotoxinas/genética , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Microbiologia de Alimentos , Plasmídeos/análise , beta-Lactamases/genética , Animais , Escherichia coli/classificação , Escherichia coli/enzimologia , Escherichia coli/isolamento & purificação , Alemanha , Humanos , Tipagem de Sequências Multilocus , Países Baixos , Reação em Cadeia da Polimerase , Reino Unido
12.
BMC Microbiol ; 16: 15, 2016 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-26846255

RESUMO

BACKGROUND: The Salmonella enterica serovar Derby is frequently isolated from pigs and turkeys whereas serovar Mbandaka is frequently isolated from cattle, chickens and animal feed in the UK. Through comparative genomics, phenomics and mutant construction we previously suggested possible mechanistic reasons why these serovars demonstrate apparently distinct host ranges. Here, we investigate the genetic and phenotypic diversity of these two serovars in the UK. We produce a phylogenetic reconstruction and perform several biochemical assays on isolates of S. Derby and S. Mbandaka acquired from sites across the UK between the years 2000 and 2010. RESULTS: We show that UK isolates of S. Mbandaka comprise of one clonal lineage which is adapted to proficient utilisation of metabolites found in soya beans under ambient conditions. We also show that this clonal lineage forms a biofilm at 25 °C, suggesting that this serovar maybe well adapted to survival ex vivo, growing in animal feed. Conversely, we show that S. Derby is made of two distinct lineages, L1 and L2. These lineages differ genotypically and phenotypically, being divided by the presence and absence of SPI-23 and the ability to more proficiently invade porcine jejunum derived cell line IPEC-J2. CONCLUSION: The results of this study lend support to the hypothesis that the differences in host ranges of S. Derby and S. Mbandaka are adaptations to pathogenesis, environmental persistence, as well as utilisation of metabolites abundant in their respective host environments.


Assuntos
Especificidade de Hospedeiro , Salmonelose Animal/microbiologia , Infecções por Salmonella/microbiologia , Salmonella enterica/isolamento & purificação , Salmonella enterica/fisiologia , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Humanos , Fenótipo , Filogenia , Doenças das Aves Domésticas/microbiologia , Salmonella enterica/classificação , Salmonella enterica/genética , Sorogrupo , Suínos , Doenças dos Suínos/microbiologia , Perus , Reino Unido
13.
Microb Ecol Health Dis ; 26: 28853, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26679774

RESUMO

Avian intestinal spirochaetosis (AIS) is a common disease occurring in poultry that can be caused by Brachyspira pilosicoli, a Gram-negative bacterium of the order Spirochaetes. During AIS, this opportunistic pathogen colonises the lower gastrointestinal (GI) tract of poultry (principally, the ileum, caeca, and colon), which can cause symptoms such as diarrhoea, reduced growth rate, and reduced egg production and quality. Due to the large increase of bacterial resistance to antibiotic treatment, the European Union banned in 2006 the prophylactic use of antibiotics as growth promoters in livestock. Consequently, the number of outbreaks of AIS has dramatically increased in the UK resulting in significant economic losses. This review summarises the current knowledge about AIS infection caused by B. pilosicoli and discusses various treatments and prevention strategies to control AIS.

14.
Microbiology (Reading) ; 160(Pt 6): 1252-1266, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24777662

RESUMO

Salmonella enterica sv. Typhimurium is an established model organism for Gram-negative, intracellular pathogens. Owing to the rapid spread of resistance to antibiotics among this group of pathogens, new approaches to identify suitable target proteins are required. Based on the genome sequence of S. Typhimurium and associated databases, a genome-scale metabolic model was constructed. Output was based on an experimental determination of the biomass of Salmonella when growing in glucose minimal medium. Linear programming was used to simulate variations in the energy demand while growing in glucose minimal medium. By grouping reactions with similar flux responses, a subnetwork of 34 reactions responding to this variation was identified (the catabolic core). This network was used to identify sets of one and two reactions that when removed from the genome-scale model interfered with energy and biomass generation. Eleven such sets were found to be essential for the production of biomass precursors. Experimental investigation of seven of these showed that knockouts of the associated genes resulted in attenuated growth for four pairs of reactions, whilst three single reactions were shown to be essential for growth.


Assuntos
Redes e Vias Metabólicas/genética , Salmonella typhimurium/genética , Antibacterianos/farmacologia , Biomassa , Simulação por Computador , Meios de Cultura/química , Técnicas de Inativação de Genes , Genômica , Glucose/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/crescimento & desenvolvimento
15.
J Antimicrob Chemother ; 69(8): 2098-101, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24729584

RESUMO

OBJECTIVES: In 2009, CTX-M Enterobacteriaceae and Salmonella isolates were recovered from a UK pig farm, prompting studies into the dissemination of the resistance and to establish any relationships between the isolates. METHODS: PFGE was used to elucidate clonal relationships between isolates whilst plasmid profiling, restriction analysis, sequencing and PCR were used to characterize the CTX-M-harbouring plasmids. RESULTS: Escherichia coli, Klebsiella pneumoniae and Salmonella 4,5,12:i:- and Bovismorbificans resistant to cefotaxime (n = 65) were recovered and 63 were shown by PCR to harbour a group 1 CTX-M gene. The harbouring hosts were diverse, but the group 1 CTX-M plasmids were common. Three sequenced CTX-M plasmids from E. coli, K. pneumoniae and Salmonella enterica serotype 4,5,12:i:- were identical except for seven mutations and highly similar to IncI1 plasmid ColIb-P9. Two antimicrobial resistance regions were identified: one inserted upstream of yacABC harbouring ISCR2 transposases, sul2 and floR; and the other inserted within shfB of the pilV shufflon harbouring the ISEcp1 transposase followed by blaCTX-M-1. CONCLUSIONS: These data suggest that an ST108 IncI1 plasmid encoding a blaCTX-M-1 gene had disseminated across multiple genera on this farm, an example of horizontal gene transfer of the blaCTX-M-1 gene.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Klebsiella pneumoniae/genética , Salmonella enterica/genética , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Sequência de Bases , Cefotaxima/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/veterinária , Transferência Genética Horizontal , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/veterinária , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Mutação , Plasmídeos/genética , Salmonelose Animal/tratamento farmacológico , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação , Análise de Sequência de DNA , Suínos , Reino Unido
16.
Appl Environ Microbiol ; 80(2): 478-85, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24212578

RESUMO

The animal gastrointestinal tract houses a large microbial community, the gut microbiota, that confers many benefits to its host, such as protection from pathogens and provision of essential metabolites. Metagenomic approaches have defined the chicken fecal microbiota in other studies, but here, we wished to assess the correlation between the metagenome and the bacterial proteome in order to better understand the healthy chicken gut microbiota. Here, we performed high-throughput sequencing of 16S rRNA gene amplicons and metaproteomics analysis of fecal samples to determine microbial gut composition and protein expression. 16 rRNA gene sequencing analysis identified Clostridiales, Bacteroidaceae, and Lactobacillaceae species as the most abundant species in the gut. For metaproteomics analysis, peptides were generated by using the Fasp method and subsequently fractionated by strong anion exchanges. Metaproteomics analysis identified 3,673 proteins. Among the most frequently identified proteins, 380 proteins belonged to Lactobacillus spp., 155 belonged to Clostridium spp., and 66 belonged to Streptococcus spp. The most frequently identified proteins were heat shock chaperones, including 349 GroEL proteins, from many bacterial species, whereas the most abundant enzymes were pyruvate kinases, as judged by the number of peptides identified per protein (spectral counting). Gene ontology and KEGG pathway analyses revealed the functions and locations of the identified proteins. The findings of both metaproteomics and 16S rRNA sequencing analyses are discussed.


Assuntos
Adaptação Fisiológica , Proteínas de Bactérias/metabolismo , Galinhas/microbiologia , Trato Gastrointestinal/microbiologia , Microbiota , Proteômica/métodos , Animais , Bactérias/genética , Proteínas de Bactérias/genética , Chaperonina 60/metabolismo , Fezes/microbiologia , Ontologia Genética , Lactobacillus/genética , Microbiota/genética , RNA Ribossômico 16S
17.
Proc Natl Acad Sci U S A ; 108(8): 3330-5, 2011 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-21300860

RESUMO

αß T-cell repertoire selection is mediated by peptide-MHC complexes presented by thymic epithelial or myeloid cells, and by lipid-CD1 complexes expressed by thymocytes. γδ T-cell repertoire selection, by contrast, is largely unresolved. Mice mutant for Skint-1, a unique Ig superfamily gene, do not develop canonical Vγ5Vδ1(+) dendritic epidermal T cells. This study shows that transgenic Skint-1, across a broad range of expression levels, precisely and selectively determines the Vγ5Vδ1(+) dendritic epidermal T-cell compartment. Skint-1 is expressed by medullary thymic epithelial cells, and unlike lipid-CD1 complexes, must be expressed by stromal cells to function efficiently. Its unusual transmembrane-cytoplasmic regions severely limit cell surface expression, yet increasing this or, conversely, retaining Skint1 intracellularly markedly compromises function. Each Skint1 domain appears nonredundant, including a unique decamer specifying IgV-domain processing. This investigation of Skint-1 biology points to complex events underpinning the positive selection of an intraepithelial γδ repertoire.


Assuntos
Epiderme/imunologia , Imunoglobulinas/imunologia , Linfócitos T/imunologia , Animais , Células Dendríticas , Células Epidérmicas , Células Epiteliais , Expressão Gênica/imunologia , Imunoglobulinas/genética , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Subpopulações de Linfócitos T
18.
BMC Genomics ; 14: 365, 2013 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-23725633

RESUMO

BACKGROUND: Despite the frequent isolation of Salmonella enterica sub. enterica serovars Derby and Mbandaka from livestock in the UK and USA little is known about the biological processes maintaining their prevalence. Statistics for Salmonella isolations from livestock production in the UK show that S. Derby is most commonly associated with pigs and turkeys and S. Mbandaka with cattle and chickens. Here we compare the first sequenced genomes of S. Derby and S. Mbandaka as a basis for further analysis of the potential host adaptations that contribute to their distinct host species distributions. RESULTS: Comparative functional genomics using the RAST annotation system showed that predominantly mechanisms that relate to metabolite utilisation, in vivo and ex vivo persistence and pathogenesis distinguish S. Derby from S. Mbandaka. Alignment of the genome nucleotide sequences of S. Derby D1 and D2 and S. Mbandaka M1 and M2 with Salmonella pathogenicity islands (SPI) identified unique complements of genes associated with host adaptation. We also describe a new genomic island with a putative role in pathogenesis, SPI-23. SPI-23 is present in several S. enterica serovars, including S. Agona, S. Dublin and S. Gallinarum, it is absent in its entirety from S. Mbandaka. CONCLUSIONS: We discovered a new 37 Kb genomic island, SPI-23, in the chromosome sequence of S. Derby, encoding 42 ORFS, ten of which are putative TTSS effector proteins. We infer from full-genome synonymous SNP analysis that these two serovars diverged, between 182kya and 625kya coinciding with the divergence of domestic pigs. The differences between the genomes of these serovars suggest they have been exposed to different stresses including, phage, transposons and prolonged externalisation. The two serovars possess distinct complements of metabolic genes; many of which cluster into pathways for catabolism of carbon sources.


Assuntos
Genômica , Gado/microbiologia , Salmonella enterica/genética , Animais , Bovinos , Genes Bacterianos/genética , Ilhas Genômicas/genética , Redes e Vias Metabólicas/genética , Anotação de Sequência Molecular , Prófagos/fisiologia , Reprodutibilidade dos Testes , Salmonella enterica/metabolismo , Salmonella enterica/virologia , Inversão de Sequência , Especificidade da Espécie , Reino Unido
19.
Brain ; 135(Pt 10): 3178-88, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22945966

RESUMO

William Gowers' classic single-authored two-volume A manual of diseases of the nervous system appeared in a first edition in 1886 and 1888, and in a second edition in 1892 and 1893, with a third edition of Volume 1 in 1899. No third edition of Volume 2 ever appeared. However, in 1949 Critchley stated that he had seen part of a revision of this volume. Subsequent writers could not find this material, but it recently came to light at Gowers' old hospital at Queen Square, London. The present paper describes the rediscovered material, containing Gowers' handwritten alterations for a further edition of Volume 2, and substantial new material, at least in relation to nystagmus and myasthenia. Gowers' declining health, or a conflict between his planned new text and his contributions to the neurology segments (1899) of Allbutt's System of medicine, may explain why a third edition of Volume 2 of the Manual of diseases of the nervous system never appeared.


Assuntos
Doenças do Sistema Nervoso/história , Neurologia/história , Terminologia como Assunto , História do Século XIX , Humanos
20.
Metabolites ; 13(3)2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36984760

RESUMO

Escherichia coli and Staphylococcus aureus are globally among the most prominent bacterial strains associated with antibacterial resistance-caused deaths. Naturally occurring polyphenols, such as hydrolyzable tannins, have been shown to potently inhibit E. coli and S. aureus. The current study investigated the metabolome changes of E. coli and S. aureus cultures after treatments with different hydrolyzable tannins using an NMR metabolomics approach. Additionally, the effect of these tannin treatments influencing a more complex bacterial system was studied in a biomimetic setting with fecal samples inoculated into the growth medium. Metabolite concentration changes were observed in all three scenarios: E. coli, S. aureus, and fecal batch culture. The metabolome of E. coli was more altered by the tannin treatments than S. aureus when compared to control cultures. A dimeric hydrolyzable tannin, rugosin D, was found to be the most effective of the studied compounds in influencing bacterial metabolome changes and in inhibiting E. coli and S. aureus growth. It was also observed that the tannin structure should have both hydrophobic and hydrophilic regions to efficiently influence E. coli and S. aureus growth.

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