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2.
Front Immunol ; 12: 632304, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33953709

RESUMEN

Cross-reactive vaccines recognize common molecular patterns in pathogens and are able to confer broad spectrum protection against different infections. Antigens common to pathogenic bacteria that induce broad immune responses, such as the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of the genera Listeria, Mycobacterium, or Streptococcus, whose sequences present more than 95% homology at the N-terminal GAPDH1-22 peptide, are putative candidates for universal vaccines. Here, we explore vaccine formulations based on dendritic cells (DC) loaded with two molecular forms of Listeria monocytogenes GAPDH (LM-GAPDH), such as mRNA carriers or recombinant proteins, and compare them with the same molecular forms of three other antigens used in experimental vaccines, listeriolysin O of Listeria monocytogeness, Ag85A of Mycobacterium marinum, and pneumolysin of Streptococcus pneumoniae. DC loaded with LM-GAPDH recombinant proteins proved to be the safest and most immunogenic vaccine vectors, followed by mRNA encoding LM-GAPDH conjugated to lipid carriers. In addition, macrophages lacked sufficient safety as vaccines for all LM-GAPDH molecular forms. The ability of DC loaded with LM-GAPDH recombinant proteins to induce non-specific DC activation explains their adjuvant potency and their capacity to trigger strong CD4+ and CD8+ T cell responses explains their high immunogenicity. Moreover, their capacity to confer protection in vaccinated mice against challenges with L. monocytogenes, M. marinum, or S. pneumoniae validated their efficiency as cross-reactive vaccines. Cross-protection appears to involve the induction of high percentages of GAPDH1-22 specific CD4+ and CD8+ T cells stained for intracellular IFN-γ, and significant levels of peptide-specific antibodies in vaccinated mice. We concluded that DC vaccines loaded with L. monocytogenes GAPDH recombinant proteins are cross-reactive vaccines that seem to be valuable tools in adult vaccination against Listeria, Mycobacterium, and Streptococcus taxonomic groups.


Asunto(s)
Vacunas Bacterianas/inmunología , Gliceraldehído-3-Fosfato Deshidrogenasas/inmunología , Lípidos/inmunología , Listeria/inmunología , Mycobacterium/inmunología , ARN Mensajero/inmunología , Streptococcus/inmunología , Adyuvantes Inmunológicos , Animales , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Infecciones Bacterianas/prevención & control , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/genética , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Protección Cruzada , Reacciones Cruzadas , Células Dendríticas/inmunología , Gliceraldehído-3-Fosfato Deshidrogenasas/genética , Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Interferón gamma/inmunología , Lípidos/química , Listeria/enzimología , Listeria/genética , Ratones , ARN Mensajero/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología
3.
Vaccines (Basel) ; 9(3)2021 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-33802959

RESUMEN

Universal vaccines can be prepared with antigens common to different pathogens. In this regard, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a common virulence factor among pathogenic bacteria of the genera Listeria, Mycobacterium and Streptococcus. Their N-terminal 22 amino acid peptides, GAPDH-L1 (Listeria), GAPDH-M1 (Mycobacterium) and GAPDH-S1 (Streptococcus), share 95-98.55% sequence homology, biochemical and MHC binding abilities and, therefore, are good candidates for universal vaccine designs. Here, we used dendritic cells (DC) as vaccine platforms to test GAPDH epitopes that conferred protection against Listeria monocytogenes, Mycobacterium marinum or Streptococcus pneumoniae in our search of epitopes for universal vaccines. DC loaded with GAPDH-L1, GAPDH-M1 or GAPDH-S1 peptides show high immunogenicity measured by the cellular DTH responses in mice, lacked toxicity and were capable of cross-protection immunity against mice infections with each one of the pathogens. Vaccine efficiency correlated with high titers of anti-GAPDH-L1 antibodies in sera of vaccinated mice, a Th1 cytokine pattern and high frequencies of GAPDH-L1-specific CD4+ and CD8+ T cells and IFN-γ producers in the spleens. We concluded that GAPDH-L1 peptide was the best epitope for universal vaccines in the Listeria, Mycobacterium or Streptococcus taxonomic groups, whose pathogenic strains caused relevant morbidities in adults and especially in the elderly.

4.
Front Cell Infect Microbiol ; 10: 573348, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33194812

RESUMEN

The glycolytic enzyme and bacterial virulence factor of Listeria monocytogenes, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH, Lmo2459), ADP-ribosylated the small GTPase, Rab5a, and blocked phagosome maturation. This inhibitory activity localized within the NAD binding domain of GAPDH at the N-terminal 1-22 peptides, also conferred listeriosis protection when used in dendritic cell-based vaccines. In this study, we explore GAPDH of Listeria, Mycobacterium, and Streptococcus spp. taxonomic groups to search for epitopes that confer broad protection against pathogenic strains of these bacteria. GAPDH multivalent epitopes are selected if they induce inhibitory actions and wide-ranging immune responses. Proteomic isolation of GAPDH from dendritic cells infected with Listeria, Mycobacterium, or Streptococcus confirmed similar enzymatic, Rab5a inhibitory and immune stimulation abilities. We identified by bioinformatics and functional analyses GAPDH N-terminal 1-22 peptides from Listeria, Mycobacterium, and Streptococcus that shared 95% sequence homology, enzymatic activity, and B and T cell immune domains. Sera obtained from patients or mice infected with hypervirulent pathogenic Listeria, Mycobacterium, or Streptococcus presented high levels of anti-GAPDH 1-22 antibodies and Th2 cytokines. Monocyte derived dendritic cells from healthy donors loaded with GAPDH 1-22 peptides from Listeria, Mycobacterium, or Streptococcus showed activation patterns that correspond to cross-immunity abilities. In summary, GAPDH 1-22 peptides appeared as putative candidates to include in multivalent dendritic based vaccine platforms for Listeria, Mycobacterium, or Streptococcus.


Asunto(s)
Listeria , Mycobacterium , Animales , Epítopos , Gliceraldehído-3-Fosfato Deshidrogenasas/genética , Humanos , Ratones , Proteómica , Streptococcus , Vacunas Combinadas
5.
mSphere ; 5(2)2020 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-32269151

RESUMEN

Carbapenemase-producing Enterobacterales (CPE) have become an important public health concern. In our hospital, VIM enzymes were first detected in 2005, Klebsiella pneumoniae carbapenemase (KPC) enzymes in 2009, and OXA-48 enzymes in 2012. We assess the population biology of the first OXA-48-producing Enterobacterales isolates recovered in our hospital (2012 to 2013) where infections by other carbapenemases had been endemic for several years. Over a 21-month period, 71 isolates (61 Klebsiella pneumoniae, 5 Escherichia coli, 2 Klebsiella aerogenes, and 1 each of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter amalonaticus) recovered from clinical and surveillance specimens from 57 patients (22.8% nonhospitalized) were investigated for OXA-48-like-producing enzymes. Analyses for characterization and determination of the location of the blaOXA-48 gene, plasmid transferability, sequence, and clonal relatedness were performed. Most of the isolates also coproduced CTX-M-15 (57/71, 80.3%) and/or VIM-1 (7/71, 9.8%). K. pneumoniae was predominantly identified as sequence type 11 (ST11) (63.4%) and ST405 (9.8%) and E. coli as ST540, ST1406, ST3163, and ST4301. The blaOXA-48 gene was part of Tn1999.2 located at the tir gene of plasmids (ca. ≥50 kb) of the IncL/M group, also carrying blaVIM-1 and blaCTX-M-15 genes. We selected one ST11 K. pneumoniae isolate for whole-genome sequencing in which we studied the plasmid containing the blaOXA-48 gene. This plasmid was compared with indexed plasmids existing in NCBI database by the use of BRIG and MAUVE. Our data suggest a rapid spread of blaOXA-48 genes between commonly isolated high-risk clones of Enterobacterales species, frequently associated with antibiotic resistance. Moreover, the emergence of the multiresistant ST11 K. pneumoniae clone among nonhospitalized patients emphasizes the difficulty of preventing its dissemination into the community.IMPORTANCE We present results of microbiological analysis of the first Enterobacterales isolates that were isolated in 2012 in our institution expressing OXA-48 carbapenemase. This enzyme confers resistance to carbapenems, an important group of antibiotics widely used in the hospitals. OXA-48 carbapenemase is currently present in many parts of the world, but it is found particularly frequently in the Mediterranean area. It was disseminated at the Ramón y Cajal Hospital and found to be associated with a particular Klebsiella pneumoniae strain, so-called high-risk clone ST11, which was previously found in our institution in association with other enzymes such as CTX-M-15, VIM-1, and KPC-3. This clone might have acquired a plasmid harboring the blaOXA-48 gene. Our results point out the importance of local epidemiology in the dissemination and maintenance of multidrug-resistant bacteria.


Asunto(s)
Infecciones por Enterobacteriaceae/epidemiología , Enterobacteriaceae/genética , Hospitales , Klebsiella pneumoniae/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Carbapenémicos/farmacología , Enterobacteriaceae/enzimología , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/microbiología , Femenino , Humanos , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/clasificación , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Plásmidos/genética , España/epidemiología , Adulto Joven , beta-Lactamasas/genética
6.
Oncoimmunology ; 8(2): e1541534, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30713801

RESUMEN

Gold glyconanoparticles loaded with the listeriolysin O peptide 91-99 (GNP-LLO91-99), a bacterial peptide with anti-metastatic properties, are vaccine delivery platforms facilitating immune cell targeting and increasing antigen loading. Here, we present proof of concept analyses for the consideration of GNP-LLO91-99 nanovaccines as a novel immunotherapy for cutaneous melanoma. Studies using mouse models of subcutaneous melanoma indicated that GNP-LLO91-99 nanovaccines recruite and modulate dendritic cell (DC) function within the tumour, alter tumour immunotolerance inducing melanoma-specific cytotoxic T cells, cause complete remission and improve survival. GNP-LLO91-99 nanovaccines showed superior tumour regression and survival benefits, when combined with anti-PD-1 or anti-CTLA-4 checkpoint inhibitors, resulting in an improvement in the efficacy of these immunotherapies. Studies on monocyte-derived DCs from patients with stage IA, IB or IIIB melanoma confirmed the ability of GNP-LLO91-99 nanovaccines to complement the action of checkpoint inhibitors, by not only reducing the expression of cell-death markers on DCs, but also potentiating DC antigen-presentation. We propose that GNP-LLO91-99 nanovaccines function as immune stimulators and immune effectors and serve as safe cancer therapies, alone or in combination with other immunotherapies.

7.
Genome Announc ; 5(13)2017 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-28360174

RESUMEN

The emergence of nosocomial infections by multidrug-resistant sequence type 117 (ST117) Enterococcus faecium has been reported in several European countries. ST117 has been detected in Spanish hospitals as one of the main causes of bloodstream infections. We analyzed genome variations of ST117 strains isolated in Madrid and describe the first ST117 closed genome sequences.

8.
J Immunol ; 196(3): 1102-7, 2016 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-26718337

RESUMEN

Guillain-Barré syndrome (GBS) is an immune-mediated peripheral neuropathy. The goal of this research was the identification of biomarkers associated with recovery from GBS. In this study, we compared the transcriptome of PBMCs from a GBS patient and her healthy twin to discover possible correlates of disease progression and recovery. The study was then extended using GBS and spinal cord injury unrelated patients with similar medications and healthy individuals. The early growth response gene-2 (EGR2) was upregulated in GBS patients during disease recovery. The results provided evidence for the implication of EGR2 in GBS and suggested a role for EGR2 in the regulation of IL-17, IL-22, IL-28A, and TNF-ß cytokines in GBS patients. These results identified biomarkers associated with GBS recovery and suggested that EGR2 overexpression has a pivotal role in the downregulation of cytokines implicated in the pathophysiology of this acute neuropathy.


Asunto(s)
Biomarcadores/análisis , Proteína 2 de la Respuesta de Crecimiento Precoz/biosíntesis , Síndrome de Guillain-Barré/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Citocinas/biosíntesis , Proteína 2 de la Respuesta de Crecimiento Precoz/inmunología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa , Recuperación de la Función , Transcriptoma , Regulación hacia Arriba , Adulto Joven
9.
PLoS Negl Trop Dis ; 9(11): e0004232, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26583774

RESUMEN

Mycobacteria of the Mycobacterium tuberculosis complex (MTBC) greatly affect humans and animals worldwide. The life cycle of mycobacteria is complex and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Recently, comparative genomics analyses have provided new insights into the evolution and adaptation of the MTBC to survive inside the host. However, most of this information has been obtained using M. tuberculosis but not other members of the MTBC such as M. bovis and M. caprae. In this study, the genome of three M. bovis (MB1, MB3, MB4) and one M. caprae (MB2) field isolates with different lesion score, prevalence and host distribution phenotypes were sequenced. Genome sequence information was used for whole-genome and protein-targeted comparative genomics analysis with the aim of finding correlates with phenotypic variation with potential implications for tuberculosis (TB) disease risk assessment and control. At the whole-genome level the results of the first comparative genomics study of field isolates of M. bovis including M. caprae showed that as previously reported for M. tuberculosis, sequential chromosomal nucleotide substitutions were the main driver of the M. bovis genome evolution. The phylogenetic analysis provided a strong support for the M. bovis/M. caprae clade, but supported M. caprae as a separate species. The comparison of the MB1 and MB4 isolates revealed differences in genome sequence, including gene families that are important for bacterial infection and transmission, thus highlighting differences with functional implications between isolates otherwise classified with the same spoligotype. Strategic protein-targeted analysis using the ESX or type VII secretion system, proteins linking stress response with lipid metabolism, host T cell epitopes of mycobacteria, antigens and peptidoglycan assembly protein identified new genetic markers and candidate vaccine antigens that warrant further study to develop tools to evaluate risks for TB disease caused by M. bovis/M.caprae and for TB control in humans and animals.


Asunto(s)
Genoma Bacteriano , Viabilidad Microbiana , Mycobacterium/genética , Mycobacterium/aislamiento & purificación , Animales , Biología Computacional , ADN Bacteriano/química , ADN Bacteriano/genética , Evolución Molecular , Genómica , Humanos , Filogenia , Análisis de Secuencia de ADN , Virulencia , Factores de Virulencia/genética
10.
Mol Cell Proteomics ; 14(12): 3154-72, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26424601

RESUMEN

Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human granulocytic anaplasmosis. These intracellular bacteria establish infection by affecting cell function in both the vertebrate host and the tick vector, Ixodes scapularis. Previous studies have characterized the tick transcriptome and proteome in response to A. phagocytophilum infection. However, in the postgenomic era, the integration of omics datasets through a systems biology approach allows network-based analyses to describe the complexity and functionality of biological systems such as host-pathogen interactions and the discovery of new targets for prevention and control of infectious diseases. This study reports the first systems biology integration of metabolomics, transcriptomics, and proteomics data to characterize essential metabolic pathways involved in the tick response to A. phagocytophilum infection. The ISE6 tick cells used in this study constitute a model for hemocytes involved in pathogen infection and immune response. The results showed that infection affected protein processing in endoplasmic reticulum and glucose metabolic pathways in tick cells. These results supported tick-Anaplasma co-evolution by providing new evidence of how tick cells limit pathogen infection, while the pathogen benefits from the tick cell response to establish infection. Additionally, ticks benefit from A. phagocytophilum infection by increasing survival while pathogens guarantee transmission. The results suggested that A. phagocytophilum induces protein misfolding to limit the tick cell response and facilitate infection but requires protein degradation to prevent ER stress and cell apoptosis to survive in infected cells. Additionally, A. phagocytophilum may benefit from the tick cell's ability to limit bacterial infection through PEPCK inhibition leading to decreased glucose metabolism, which also results in the inhibition of cell apoptosis that increases infection of tick cells. These results support the use of this experimental approach to systematically identify cell pathways and molecular mechanisms involved in tick-pathogen interactions. Data are available via ProteomeXchange with identifier PXD002181.


Asunto(s)
Anaplasma phagocytophilum/fisiología , Ehrlichiosis/veterinaria , Metabolómica/métodos , Proteómica/métodos , Garrapatas/microbiología , Animales , Línea Celular , Ehrlichiosis/genética , Ehrlichiosis/metabolismo , Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Glucosa/metabolismo , Interacciones Huésped-Patógeno , Redes y Vías Metabólicas , Biología de Sistemas/métodos
11.
Genome Announc ; 3(3)2015 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-26112781

RESUMEN

Here we report the complete genome sequences of field isolates of Mycobacterium bovis and the related mycobacterial species, Mycobacterium caprae. The genomes of three M. bovis (MB1, MB3, MB4) and one M. caprae (MB2) field isolates with different virulence, prevalence, and host distribution phenotypes were sequenced.

12.
J Immunol Methods ; 424: 111-9, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26031451

RESUMEN

Dendritic cells loaded with antigenic peptides, because of their safety and robust immune stimulation, would be ideal for induction of immunity to protect against listeriosis. However, there is no currently accepted method to predict which peptides derived from the Listeria proteome might confer protection. While elution of peptides from MHC molecules after Listeria infection yields high-affinity immune-dominant epitopes, these individual epitopes did not reliably confer Listeria protection. Instead we applied bioinformatic predictions of MHC class I and II epitopes to generate antigenic peptides that were then formulated with Advax™, a novel polysaccharide particulate adjuvant able to enhance cross-presentation prior to being screened for their ability to induce protective T-cell responses. A combination of at least four intermediate strength MHC-I binding epitopes and one weak MHC-II binding epitope when expressed in a single peptide sequence and formulated with Advax adjuvant induced a potent T-cell response and high TNF-α and IL-12 production by dendritic cells resulting in robust listeriosis protection in susceptible mice. This T-cell vaccine approach might be useful for the design of vaccines to protect against listeriosis or other intracellular infections.


Asunto(s)
Vacunas Bacterianas/inmunología , Células Dendríticas/inmunología , Epítopos de Linfocito T/inmunología , Listeria/inmunología , Listeriosis/prevención & control , Animales , Formación de Anticuerpos/inmunología , Antígenos Bacterianos/química , Antígenos Bacterianos/inmunología , Linfocitos B/inmunología , Linfocitos B/metabolismo , Biología Computacional/métodos , Citocinas/metabolismo , Citotoxicidad Inmunológica , Mapeo Epitopo/métodos , Epítopos de Linfocito T/química , Femenino , Gliceraldehído-3-Fosfato Deshidrogenasa (Fosforilante)/química , Gliceraldehído-3-Fosfato Deshidrogenasa (Fosforilante)/inmunología , Ratones , Modelos Moleculares , Péptidos/química , Péptidos/inmunología , Conformación Proteica , Reproducibilidad de los Resultados , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Vacunación
13.
J Hum Lact ; 31(3): 406-15, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25948578

RESUMEN

BACKGROUND: Some studies have been conducted to assess the composition of the bacterial communities inhabiting human milk, but they did not evaluate the presence of other microorganisms, such as fungi, archaea, protozoa, or viruses. OBJECTIVE: This study aimed to compare the metagenome of human milk samples provided by healthy and mastitis-suffering women. METHODS: DNA was isolated from human milk samples collected from 10 healthy women and 10 women with symptoms of lactational mastitis. Shotgun libraries from total extracted DNA were constructed and the libraries were sequenced by 454 pyrosequencing. RESULTS: The amount of human DNA sequences was ≥ 90% in all the samples. Among the bacterial sequences, the predominant phyla were Proteobacteria, Firmicutes, and Bacteroidetes. The healthy core microbiome included the genera Staphylococcus, Streptococcus, Bacteroides, Faecalibacterium, Ruminococcus, Lactobacillus, and Propionibacterium. At the species level, a high degree of inter-individual variability was observed among healthy women. In contrast, Staphylococcus aureus clearly dominated the microbiome in the samples from the women with acute mastitis whereas high increases in Staphylococcus epidermidis-related reads were observed in the milk of those suffering from subacute mastitis. Fungal and protozoa-related reads were identified in most of the samples, whereas Archaea reads were absent in samples from women with mastitis. Some viral-related sequence reads were also detected. CONCLUSION: Human milk contains a complex microbial metagenome constituted by the genomes of bacteria, archaea, viruses, fungi, and protozoa. In mastitis cases, the milk microbiome reflects a loss of bacterial diversity and a high increase of the sequences related to the presumptive etiological agents.


Asunto(s)
Mastitis/microbiología , Metagenoma , Microbiota/genética , Leche Humana/microbiología , Estudios de Casos y Controles , Femenino , Humanos
14.
Genome Announc ; 3(1)2015 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-25614563

RESUMEN

We report here the complete genome sequencing of Ehrlichia mineirensis, an Ehrlichia organism that was isolated from the hemolymph of Rhipicephalus microplus-engorged females. E. mineirensis is the best characterized Ehrlichia isolate from a novel cattle-related clade closely related to the monocytotropic pathogen E. canis.

15.
Methods Mol Biol ; 1231: 177-89, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25343866

RESUMEN

New massive sequencing technologies are providing many bacterial genome sequences from diverse taxa but a refined annotation of these genomes is crucial for obtaining scientific findings and new knowledge. Thus, bacterial genome annotation has emerged as a key point to investigate in bacteria. Any efficient tool designed specifically to annotate bacterial genomes sequenced with massively parallel technologies has to consider the specific features of bacterial genomes (absence of introns and scarcity of nonprotein-coding sequence) and of next-generation sequencing (NGS) technologies (presence of errors and not perfectly assembled genomes). These features make it convenient to focus on coding regions and, hence, on protein sequences that are the elements directly related with biological functions. In this chapter we describe how to annotate bacterial genomes with BG7, an open-source tool based on a protein-centered gene calling/annotation paradigm. BG7 is specifically designed for the annotation of bacterial genomes sequenced with NGS. This tool is sequence error tolerant maintaining their capabilities for the annotation of highly fragmented genomes or for annotating mixed sequences coming from several genomes (as those obtained through metagenomics samples). BG7 has been designed with scalability as a requirement, with a computing infrastructure completely based on cloud computing (Amazon Web Services).


Asunto(s)
Mapeo Contig/métodos , Genoma Bacteriano , Secuenciación de Nucleótidos de Alto Rendimiento , Anotación de Secuencia Molecular/métodos , Análisis de Secuencia de ADN/instrumentación , Programas Informáticos , Bacterias/genética , Secuencia de Bases , Procesamiento Automatizado de Datos , Metagenómica , Anotación de Secuencia Molecular/estadística & datos numéricos , Datos de Secuencia Molecular , Alineación de Secuencia , Análisis de Secuencia de ADN/métodos
16.
Mol Ecol Resour ; 14(5): 1095, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24976445

RESUMEN

This article documents the public availability of a global transcriptome comparison between Lyme disease tick vectors, Ixodes scapularis and Ixodes ricinus.


Asunto(s)
Ixodes/genética , Transcriptoma , Animales
17.
PLoS One ; 9(2): e89564, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24586875

RESUMEN

BACKGROUND: Dermacentor reticulatus (Fabricius, 1794) is distributed in Europe and Asia where it infests and transmits disease-causing pathogens to humans, pets and other domestic and wild animals. However, despite its role as a vector of emerging or re-emerging diseases, very little information is available on the genome, transcriptome and proteome of D. reticulatus. Tick larvae are the first developmental stage to infest hosts, acquire infection and transmit pathogens that are transovarially transmitted and are exposed to extremely stressing conditions. In this study, we used a systems biology approach to get an insight into the mechanisms active in D. reticulatus unfed larvae, with special emphasis on stress response. PRINCIPAL FINDINGS: The results support the use of paired end RNA sequencing and proteomics informed by transcriptomics (PIT) for the analysis of transcriptomics and proteomics data, particularly for organisms such as D. reticulatus with little sequence information available. The results showed that metabolic and cellular processes involved in protein synthesis were the most active in D. reticulatus unfed larvae, suggesting that ticks are very active during this life stage. The stress response was activated in D. reticulatus unfed larvae and a Rickettsia sp. similar to R. raoultii was identified in these ticks. SIGNIFICANCE: The activation of stress responses in D. reticulatus unfed larvae likely counteracts the negative effect of temperature and other stress conditions such as Rickettsia infection and favors tick adaptation to environmental conditions to increase tick survival. These results show mechanisms that have evolved in D. reticulatus ticks to survive under stress conditions and suggest that these mechanisms are conserved across hard tick species. Targeting some of these proteins by vaccination may increase tick susceptibility to natural stress conditions, which in turn reduce tick survival and reproduction, thus reducing tick populations and vector capacity for tick-borne pathogens.


Asunto(s)
Vectores Arácnidos/fisiología , Dermacentor/fisiología , Estrés Fisiológico , Animales , Vectores Arácnidos/microbiología , Proteínas de Artrópodos/genética , Proteínas de Artrópodos/metabolismo , Dermacentor/microbiología , Privación de Alimentos , Genes Bacterianos , Larva/microbiología , Larva/fisiología , Biosíntesis de Proteínas , Proteoma/genética , Proteoma/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Rickettsia/genética , Biología de Sistemas , Transcriptoma
18.
J Antimicrob Chemother ; 69(3): 632-6, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24155060

RESUMEN

OBJECTIVES: To characterize at the genomic level the evolution of multiresistance during an outbreak of Klebsiella pneumoniae in a burns intensive care unit. The outbreak involved a DHA-1 ß-lactamase-producing strain that later acquired carbapenem and fosfomycin resistance, and in one case colistin resistance. METHODS: The genomes of two isolates were sequenced and compared with a previously sequenced genome. The role of hypermutability was investigated by measuring the mutation frequencies of the isolates and comparison with a collection of control strains. RESULTS: Sequence comparison identified four single-nucleotide variants and two transposon insertions. Analysis of the variants in the whole collection related carbapenem and fosfomycin resistance to a nonsense mutation in the ompK36 porin gene and colistin resistance to an IS1 insertion in the mgrB gene. The plasmid carrying the blaDHA-1 gene was unstable in the absence of antibiotics, and analysis of isolates that had lost the plasmid showed that the porin mutation alone was not sufficient to generate carbapenem resistance. The mutation frequencies were similar among all the strains analysed. CONCLUSIONS: Carbapenem resistance required production of the DHA-1 ß-lactamase and decreased permeability, but fosfomycin resistance depended only on permeability. Resistance to colistin might be related to an alteration in the regulation of the phoPQ system. Hypermutation is not related to the selection of porin mutants. Plasmid instability might be due to the high number of mobile elements and suggests a major role for antibiotic selection pressure in the emergence and evolution of this outbreak.


Asunto(s)
Carbapenémicos/farmacología , Colistina/farmacología , Brotes de Enfermedades , Resistencia a Múltiples Medicamentos , Evolución Molecular , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Adulto , Anciano , Antibacterianos/farmacología , ADN Bacteriano/química , ADN Bacteriano/genética , Femenino , Genoma Bacteriano , Humanos , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Tasa de Mutación , Análisis de Secuencia de ADN
19.
PLoS One ; 8(9): e72963, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24069167

RESUMEN

The rate at which mutations are generated is central to the pace of evolution. Although this rate is remarkably similar amongst all cellular organisms, bacterial strains with mutation rates 100 fold greater than the modal rates of their species are commonly isolated from natural sources and emerge in experimental populations. Theoretical studies postulate and empirical studies teort the hypotheses that these "mutator" strains evolved in response to selection for elevated rates of generation of inherited variation that enable bacteria to adapt to novel and/or rapidly changing environments. Less clear are the conditions under which selection will favor reductions in mutation rates. Declines in rates of mutation for established populations of mutator bacteria are not anticipated if such changes are attributed to the costs of augmented rates of generation of deleterious mutations. Here we report experimental evidence of evolution towards reduced mutation rates in a clinical isolate of Escherichia coli with an hyper-mutable phenotype due a deletion in a mismatch repair gene, (ΔmutS). The emergence in a ΔmutS background of variants with mutation rates approaching those of the normal rates of strains carrying wild-type MutS was associated with increase in fitness with respect to ancestral strain. We postulate that such an increase in fitness could be attributed to the emergence of mechanisms driving a permanent "aerobic style of life", the negative consequence of this behavior being regulated by the evolution of mechanisms protecting the cell against increased endogenous oxidative radicals involved in DNA damage, and thus reducing mutation rate. Gene expression assays and full sequencing of evolved mutator and normo-mutable variants supports the hypothesis. In conclusion, we postulate that the observed reductions in mutation rate are coincidental to, rather than, the selective force responsible for this evolution.


Asunto(s)
Escherichia coli/genética , Proteínas de Escherichia coli/genética , Evolución Molecular , Tasa de Mutación
20.
Genome Announc ; 1(3)2013 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-23704175

RESUMEN

We present the first complete genome sequence of a Staphylococcus aureus strain assigned to clonal complex 12. The strain was isolated in a food poisoning outbreak due to contaminated potato salad in Switzerland in 2009, and it produces staphylococcal enterotoxin B.

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