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1.
Microbiology (Reading) ; 164(9): 1196-1211, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30052173

RESUMO

Burkholderia pseudomallei, the aetiological agent of melioidosis, is an inhabitant of soil and water in many tropical and subtropical regions worldwide. It possesses six distinct type VI secretion systems (T6SS-1 to T6SS-6), but little is known about most of them, as they are poorly expressed in laboratory culture media. A genetic screen was devised to locate a putative repressor of the T6SS-2 gene cluster and a MarR family transcriptional regulator, termed TctR, was identified. The inactivation of tctR resulted in a 50-fold increase in the expression of an hcp2-lacZ transcriptional fusion, indicating that TctR is a negative regulator of the T6SS-2 gene cluster. Surprisingly, the tctR mutation resulted in a significant decrease in the expression of an hcp6-lacZ transcriptional fusion. B. pseudomallei K96243 and a tctR mutant were grown to logarithmic phase in rich culture medium and RNA was isolated and sequenced in order to identify other genes regulated by TctR. The results identified seven gene clusters that were repressed by TctR, including T6SS-2, and three gene clusters that were significantly activated. A small molecule library consisting of 1120 structurally defined compounds was screened to identify a putative ligand (or ligands) that might bind TctR and derepress transcription of the T6SS-2 gene cluster. Seven compounds, six fluoroquinolones and one quinolone, activated the expression of hcp2-lacZ. Subinhibitory ciprofloxacin also increased the expression of the T6SS-3, T6SS-4 and T6SS-6 gene clusters. This study highlights the complex layers of regulatory control that B. pseudomallei utilizes to ensure that T6SS expression only occurs under very defined environmental conditions.


Assuntos
Antibacterianos/farmacologia , Burkholderia pseudomallei/efeitos dos fármacos , Burkholderia pseudomallei/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Família Multigênica , Fatores de Transcrição/metabolismo , Sistemas de Secreção Tipo VI/metabolismo , Burkholderia pseudomallei/genética , Perfilação da Expressão Gênica , Regulon , Fatores de Transcrição/genética
2.
PLoS Pathog ; 11(4): e1004834, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25909486

RESUMO

Invasive aspergillosis (IA) due to Aspergillus fumigatus is a major cause of mortality in immunocompromised patients. The discovery of highly fertile strains of A. fumigatus opened the possibility to merge classical and contemporary genetics to address key questions about this pathogen. The merger involves sexual recombination, selection of desired traits, and genomics to identify any associated loci. We constructed a highly fertile isogenic pair of A. fumigatus strains with opposite mating types and used them to investigate whether mating type is associated with virulence and to find the genetic loci involved in azole resistance. The pair was made isogenic by 9 successive backcross cycles of the foundational strain AFB62 (MAT1-1) with a highly fertile (MAT1-2) progeny. Genome sequencing showed that the F9 MAT1-2 progeny was essentially identical to the AFB62. The survival curves of animals infected with either strain in three different animal models showed no significant difference, suggesting that virulence in A. fumigatus was not associated with mating type. We then employed a relatively inexpensive, yet highly powerful strategy to identify genomic loci associated with azole resistance. We used traditional in vitro drug selection accompanied by classical sexual crosses of azole-sensitive with resistant isogenic strains. The offspring were plated under varying drug concentrations and pools of resulting colonies were analyzed by whole genome sequencing. We found that variants in 5 genes contributed to azole resistance, including mutations in erg11A (cyp51A), as well as multi-drug transporters, erg25, and in HMG-CoA reductase. The results demonstrated that with minimal investment into the sequencing of three pools from a cross of interest, the variation(s) that contribute any phenotype can be identified with nucleotide resolution. This approach can be applied to multiple areas of interest in A. fumigatus or other heterothallic pathogens, especially for virulence associated traits.


Assuntos
Antifúngicos/farmacologia , Aspergillus fumigatus/efeitos dos fármacos , Azóis/farmacologia , Farmacorresistência Fúngica Múltipla , Hidroximetilglutaril-CoA Redutases/metabolismo , Oxigenases de Função Mista/metabolismo , Esterol 14-Desmetilase/metabolismo , Animais , Antifúngicos/uso terapêutico , Aspergilose/tratamento farmacológico , Aspergilose/microbiologia , Aspergilose/patologia , Aspergillus fumigatus/isolamento & purificação , Aspergillus fumigatus/metabolismo , Aspergillus fumigatus/patogenicidade , Azóis/uso terapêutico , Cruzamentos Genéticos , Farmacorresistência Fúngica Múltipla/efeitos dos fármacos , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos Tipo Acasalamento/efeitos dos fármacos , Loci Gênicos/efeitos dos fármacos , Hidroximetilglutaril-CoA Redutases/genética , Itraconazol/farmacologia , Itraconazol/uso terapêutico , Larva/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Oxigenases de Função Mista/genética , Mariposas/efeitos dos fármacos , Mutação , Esterol 14-Desmetilase/genética , Análise de Sobrevida , Triazóis/farmacologia , Triazóis/uso terapêutico , Virulência/efeitos dos fármacos , Voriconazol/farmacologia , Voriconazol/uso terapêutico
3.
BMC Genomics ; 17(1): 767, 2016 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-27716057

RESUMO

BACKGROUND: The genus Bordetella consists of nine species that include important respiratory pathogens such as the 'classical' species B. bronchiseptica, B. pertussis and B. parapertussis and six more distantly related and less extensively studied species. Here we analyze sequence diversity and gene content of 128 genome sequences from all nine species with focus on the evolution of virulence-associated factors. RESULTS: Both genome-wide sequence-based and gene content-based phylogenetic trees divide the genus into three species clades. The phylogenies are congruent between species suggesting genus-wide co-evolution of sequence diversity and gene content, but less correlated within species, mainly because of strain-specific presence of many different prophages. We compared the genomes with focus on virulence-associated genes and identified multiple clade-specific, species-specific and strain-specific events of gene acquisition and gene loss, including genes encoding O-antigens, protein secretion systems and bacterial toxins. Gene loss was more frequent than gene gain throughout the evolution, and loss of hundreds of genes was associated with the origin of several species, including the recently evolved human-restricted B. pertussis and B. holmesii, B. parapertussis and the avian pathogen B. avium. CONCLUSIONS: Acquisition and loss of multiple genes drive the evolution and speciation in the genus Bordetella, including large scale gene loss associated with the origin of several species. Recent loss and functional inactivation of genes, including those encoding pertussis vaccine components and bacterial toxins, in individual strains emphasize ongoing evolution.


Assuntos
Bordetella/classificação , Bordetella/genética , Evolução Molecular , Genoma Bacteriano , Fatores de Virulência/genética , Animais , Sistemas de Secreção Bacterianos/genética , Infecções por Bordetella/microbiologia , Conjuntos de Dados como Assunto , Genes Bacterianos , Variação Genética , Genômica , Genótipo , Humanos , Tipagem de Sequências Multilocus , Filogenia , Polimorfismo de Nucleotídeo Único
4.
Plasmid ; 83: 8-11, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26746359

RESUMO

The genomes of a diverse set of Escherichia coli, including many Shiga toxin-producing strains of various serotypes were determined. A total of 39 plasmids were identified among these strains, and many carried virulence or putative virulence genes of Shiga toxin-producing E. coli strains, virulence genes for other pathogenic E. coli groups, and some had combinations of these genes. Among the novel plasmids identified were eight that carried resistance genes to aminoglycosides, carbapenems, penicillins, cephalosporins, chloramphenicol, dihydrofolate reductase inhibitors, sulfonamides, tetracyclines and resistance to heavy metals. Two of the plasmids carried six of these resistance genes and two novel IncHI2 plasmids were also identified. The results of this study showed that plasmids carrying diverse resistance and virulence genes of various pathogenic E. coli groups can be found in E. coli strains and serotypes regardless of the isolate's source and therefore, is consistent with the premise that these mobile elements carrying these traits may be broadly disseminated among E. coli.


Assuntos
Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Escherichia coli/patogenicidade , Plasmídeos/efeitos dos fármacos , Animais , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Genes Bacterianos , Genoma Bacteriano , Humanos , Metais Pesados/farmacologia , Plasmídeos/genética , Escherichia coli Shiga Toxigênica/efeitos dos fármacos , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Escherichia coli Shiga Toxigênica/patogenicidade
5.
Int J Syst Evol Microbiol ; 66(12): 5452-5459, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27707434

RESUMO

Bordetella hinzii is known to cause respiratory disease in poultry and has been associated with a variety of infections in immunocompromised humans. In addition, there are several reports of B. hinzii infections in laboratory-raised mice. Here we sequenced and analysed the complete genome sequences of multiple B. hinzii-like isolates, obtained from vendor-supplied C57BL/6 mice in animal research facilities on different continents, and we determined their taxonomic relationship to other Bordetella species. The whole-genome based and 16S rRNA gene based phylogenies each identified two separate clades in B. hinzii, one was composed of strains isolated from poultry, humans and a rabbit whereas the other clade was restricted to isolates from mice. Distinctly different estimated DNA-DNA hybridization values, average nucleotide identity scores, gene content, metabolic profiles and host specificity all provide compelling evidence for delineation of the two species, B. hinzii - from poultry, humans and rabbit - and Bordetella pseudohinzii sp. nov. type strain 8-296-03T (=NRRL B-59942T=NCTC 13808T) that infect mice.


Assuntos
Bordetella/classificação , Camundongos Endogâmicos C57BL/microbiologia , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bordetella/genética , Bordetella/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/análise , Humanos , Camundongos , Hibridização de Ácido Nucleico , Aves Domésticas , RNA Ribossômico 16S/genética , Coelhos , Análise de Sequência de DNA
6.
BMC Bioinformatics ; 16: 31, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25638274

RESUMO

BACKGROUND: Microbiome studies incorporate next-generation sequencing to obtain profiles of microbial communities. Data generated from these experiments are high-dimensional with a rich correlation structure but modest sample sizes. A statistical model that utilizes these microbiome profiles to explain a clinical or biological endpoint needs to tackle high-dimensionality resulting from the very large space of variable configurations. Ensemble models are a class of approaches that can address high-dimensionality by aggregating information across large model spaces. Although such models are popular in fields as diverse as economics and genetics, their performance on microbiome data has been largely unexplored. RESULTS: We developed a simulation framework that accurately captures the constraints of experimental microbiome data. Using this setup, we systematically evaluated a selection of both frequentist and Bayesian regression modeling ensembles. These are represented by variants of stability selection in conjunction with elastic net and spike-and-slab Bayesian model averaging (BMA), respectively. BMA ensembles that explore a larger space of models relative to stability selection variants performed better and had lower variability across simulations. However, stability selection ensembles were able to match the performance of BMA in scenarios of low sparsity where several variables had large regression coefficients. CONCLUSIONS: Given a microbiome dataset of interest, we present a methodology to generate simulated data that closely mimics its characteristics in a manner that enables meaningful evaluation of analytical strategies. Our evaluation demonstrates that the largest ensembles yield the strongest performance on microbiome data with modest sample sizes and high-dimensional measurements. We also demonstrate the ability of these ensembles to identify microbiome signatures that are associated with opportunistic Candida albicans colonization during antibiotic exposure. As the focus of microbiome research evolves from pilot to translational studies, we anticipate that our strategy will aid investigators in making evaluation-based decisions for selecting appropriate analytical methods.


Assuntos
Teorema de Bayes , Candida albicans/crescimento & desenvolvimento , Candidíase/microbiologia , Microbiota , Modelos Estatísticos , Antibacterianos/farmacologia , Candida albicans/efeitos dos fármacos , Candidíase/tratamento farmacológico , Simulação por Computador , Projetos de Pesquisa
7.
BMC Genomics ; 15: 159, 2014 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-24568630

RESUMO

BACKGROUND: The unfolded protein response (UPR) is a network of intracellular signaling pathways that supports the ability of the secretory pathway to maintain a balance between the load of proteins entering the endoplasmic reticulum (ER) and the protein folding capacity of the ER lumen. Current evidence indicates that several pathogenic fungi rely heavily on this pathway for virulence, but there is limited understanding of the mechanisms involved. The best known functional output of the UPR is transcriptional upregulation of mRNAs involved in ER homeostasis. However, this does not take into account mechanisms of translational regulation that involve differential loading of ribosomes onto mRNAs. In this study, a global analysis of transcript-specific translational regulation was performed in the pathogenic mold Aspergillus fumigatus to determine the nature and scope of the translational response to ER stress. RESULTS: ER stress was induced by treating the fungus with dithiothreitol, tunicamycin, or a thermal up-shift. The mRNAs were then fractionated on the basis of ribosome occupancy into an under-translated pool (U) and a well-translated pool (W). The mRNAs were used to interrogate microarrays and the ratio of the hybridization signal (W/U) was used as an indicator of the relative translational efficiency of a mRNA under each condition. The largest category of translationally upregulated mRNAs during ER stress encoded proteins involved in translation. Components of the ergosterol and GPI anchor biosynthetic pathways also showed increased polysome association, suggesting an important role for translational regulation in membrane and cell wall homeostasis. ER stress induced limited remodeling of the secretory pathway translatome. However, a select group of transcription factors was translationally upregulated, providing a link to subsequent modification of the transcriptome. Finally, we provide evidence that one component of the ER stress translatome is a novel mRNA isoform from the yvc1 gene that is induced by ER stress in a UPR-dependent manner. CONCLUSIONS: Together, these findings define a core set of mRNAs subject to translational control during the adaptive response to acute ER stress in A. fumigatus and reveal a remarkable breadth of functions that are needed to resolve ER stress in this organism.


Assuntos
Aspergillus fumigatus/genética , Aspergillus fumigatus/metabolismo , Estresse do Retículo Endoplasmático , Polirribossomos/metabolismo , Biossíntese de Proteínas , Adaptação Biológica , Membrana Celular/metabolismo , Parede Celular/metabolismo , Análise por Conglomerados , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Temperatura Alta , Isoformas de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Via Secretória , Transcrição Gênica , Resposta a Proteínas não Dobradas
8.
Mycopathologia ; 178(5-6): 331-9, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24996522

RESUMO

We utilized RNAseq analysis of the Aspergillus fumigatus response to early hypoxic condition exposure. The results show that more than 89% of the A. fumigatus genome is expressed under normoxic and hypoxic conditions. Replicate samples were highly reproducible; however, comparisons between normoxia and hypoxia revealed that >23 and 35% of genes were differentially expressed after 30 and 120 min of hypoxia exposure, respectively. Consistent with our previous report detailing transcriptomic and proteomic responses at later time points, the results here show major repression of ribosomal function and induction of ergosterol biosynthesis, as well as activation of alternate respiratory mechanisms at the later time point. RNAseq data were used to define 32 hypoxia-specific genes, which were not expressed under normoxic conditions. Transcripts of a C6 transcription factor and a histidine kinase-response regulator were found only in hypoxia. In addition, several genes involved in the phosphoenylpyruvate and D-glyceraldehyde-3-phosphate metabolism were only expressed in hypoxia. Interestingly, a 216-bp ncRNA Afu-182 in the 3' region of insA (AFUB_064770) was significantly repressed under hypoxia with a 40-fold reduction in expression. A detailed analysis of Afu-182 showed similarity with several genes in the genome, many of which were also repressed in hypoxia. The results from this study show that hypoxia induces very early and widely drastic genome-wide responses in A. fumigatus that include expression of protein-coding and ncRNA genes. The role of these ncRNA genes in regulating the fungal hypoxia response is an exciting future research direction.


Assuntos
Aspergillus fumigatus/fisiologia , Regulação Fúngica da Expressão Gênica , RNA não Traduzido/metabolismo , Estresse Fisiológico , Anaerobiose , Aspergillus fumigatus/genética , Perfilação da Expressão Gênica , Análise de Sequência de DNA
9.
J Bacteriol ; 194(22): 6356-7, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23105085

RESUMO

Burkholderia multivorans is a Gram-negative bacterium and a member of the Burkholderia cepacia complex, which is frequently associated with respiratory infections in people with cystic fibrosis (CF) and chronic granulomatous disease (CGD). We are reporting the genome sequences of 4 B. multivorans strains, 2 from CF patients and 2 from CGD patients.


Assuntos
Burkholderia/classificação , Burkholderia/genética , Fibrose Cística/microbiologia , Genoma Bacteriano , Doença Granulomatosa Crônica/microbiologia , Humanos , Dados de Sequência Molecular
10.
PLoS Pathog ; 6(4): e1000845, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20368977

RESUMO

Certain environmental microorganisms can cause severe human infections, even in the absence of an obvious requirement for transition through an animal host for replication ("accidental virulence"). To understand this process, we compared eleven isolate genomes of Burkholderia pseudomallei (Bp), a tropical soil microbe and causative agent of the human and animal disease melioidosis. We found evidence for the existence of several new genes in the Bp reference genome, identifying 282 novel genes supported by at least two independent lines of supporting evidence (mRNA transcripts, database homologs, and presence of ribosomal binding sites) and 81 novel genes supported by all three lines. Within the Bp core genome, 211 genes exhibited significant levels of positive selection (4.5%), distributed across many cellular pathways including carbohydrate and secondary metabolism. Functional experiments revealed that certain positively selected genes might enhance mammalian virulence by interacting with host cellular pathways or utilizing host nutrients. Evolutionary modifications improving Bp environmental fitness may thus have indirectly facilitated the ability of Bp to colonize and survive in mammalian hosts. These findings improve our understanding of the pathogenesis of melioidosis, and establish Bp as a model system for studying the genetics of accidental virulence.


Assuntos
Evolução Biológica , Burkholderia pseudomallei/genética , Burkholderia pseudomallei/patogenicidade , Genes Bacterianos , Animais , Sequência de Bases , Feminino , Imunofluorescência , Perfilação da Expressão Gênica , Genoma Bacteriano , Melioidose/genética , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Virulência/genética
11.
BMC Microbiol ; 10: 202, 2010 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-20667135

RESUMO

BACKGROUND: Burkholderia species exhibit enormous phenotypic diversity, ranging from the nonpathogenic, soil- and water-inhabiting Burkholderia thailandensis to the virulent, host-adapted mammalian pathogen B. mallei. Genomic diversity is evident within Burkholderia species as well. Individual isolates of Burkholderia pseudomallei and B. thailandensis, for example, carry a variety of strain-specific genomic islands (GIs), including putative pathogenicity and metabolic islands, prophage-like islands, and prophages. These GIs may provide some strains with a competitive advantage in the environment and/or in the host relative to other strains. RESULTS: Here we present the results of analysis of 37 prophages, putative prophages, and prophage-like elements from six different Burkholderia species. Five of these were spontaneously induced to form bacteriophage particles from B. pseudomallei and B. thailandensis strains and were isolated and fully sequenced; 24 were computationally predicted in sequenced Burkholderia genomes; and eight are previously characterized prophages or prophage-like elements. The results reveal numerous differences in both genome structure and gene content among elements derived from different species as well as from strains within species, due in part to the incorporation of additional DNA, or 'morons' into the prophage genomes. Implications for pathogenicity are also discussed. Lastly, RNAseq analysis of gene expression showed that many of the genes in varphi1026b that appear to contribute to phage and lysogen fitness were expressed independently of the phage structural and replication genes. CONCLUSIONS: This study provides the first estimate of the relative contribution of prophages to the vast phenotypic diversity found among the Burkholderiae.


Assuntos
Bacteriófagos/fisiologia , Burkholderia/genética , Burkholderia/virologia , Variação Genética , Prófagos/fisiologia , Bacteriófagos/classificação , Bacteriófagos/genética , Burkholderia/classificação , Genoma Bacteriano , Genoma Viral , Interações Hospedeiro-Patógeno , Dados de Sequência Molecular , Filogenia , Prófagos/classificação , Prófagos/genética , Especificidade da Espécie
12.
Microbiol Resour Announc ; 9(3)2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31948962

RESUMO

The annotated genome of Aspergillus tanneri, a recently discovered drug-resistant pathogen, was determined by employing the Oxford Nanopore MinION platform and the Funannotate pipeline. The genome size and the number of protein-coding genes are notably larger than those of the most common etiological agent of aspergillosis, Aspergillus fumigatus.

13.
Med Mycol ; 47 Suppl 1: S88-96, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19255906

RESUMO

Secondary metabolites are of intense interest to humans due to their pharmaceutical and/or toxic properties. Also, these metabolites are clinically relevant because of their importance in fungal pathogenesis. Aspergillus species secrete secondary metabolites when grown individually and in the presence of other fungal species. However, it is not known whether secreted secondary metabolites provide a competitive advantage over other fungal species, or whether competition has any effect on the production of those metabolites. Here, we have performed co-cultivation competition assays among different species of Aspergillus to determine relative species fitness in culture, and to analyze the presence of possible antifungal activity of secondary metabolites in extracts. The results show that, for the most part, at 30 degrees C only one species is able to survive direct competition with a second species. In contrast, survival of both competitors was often observed at 37 degrees C. Consistent with these observations, antifungal activity of extracts from cultures grown at 30 degrees C was greater than that of extract from cultures at 37 degrees C. Interestingly, culture extracts from all species studied had some degree of antifungal activity, but in general, the extracts had greater antifungal activity when species were grown in the presence of a competitor. Using gas chromatography it was determined that the composition of extracts changed due to competition and a shift in temperature. These findings indicate that co-cultivation could be a very promising method for inducing and characterizing novel antifungal compounds produced by species of Aspergillus.


Assuntos
Antibiose , Aspergillus/fisiologia , Metabolômica , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Cromatografia Gasosa , Técnicas de Cocultura , Meios de Cultura/química , Humanos , Viabilidade Microbiana , Temperatura
14.
G3 (Bethesda) ; 9(12): 4087-4096, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31601618

RESUMO

Aspergillus flavus colonizes numerous oil seed crops such as maize, peanuts, treenuts and cottonseed worldwide, contaminating them with aflatoxins and other harmful toxins. Previously our lab characterized the gene rmtA, which encodes an arginine methyltransferase in A. flavus, and demonstrated its role governing the expression of regulators in the aflatoxin gene cluster and subsequent synthesis of toxin. Furthermore, our studies revealed that rmtA also controls conidial and sclerotial development implicating it as an epigenetic regulator in A. flavus To confirm this, we performed a RNA sequencing analysis to ascertain the extent of rmtA's influence on the transcriptome of A. flavus In this analysis we identified over 2000 genes that were rmtA-dependent, including over 200 transcription factor genes, as well as an uncharacterized secondary metabolite gene cluster possibly responsible for the synthesis of an epidithiodiketopiperazine-like compound. Our results also revealed rmtA-dependent genes involved in multiple types of abiotic stress response in A. flavus Importantly, hundreds of genes active during maize infection were also regulated by rmtA In addition, in the animal infection model, rmtA was dispensable for virulence, however forced overexpression of rmtA increased mortality with respect to the wild type.


Assuntos
Aspergillus flavus/genética , Aspergillus flavus/patogenicidade , Proteínas Fúngicas/metabolismo , Metabolismo Secundário/genética , Estresse Fisiológico/genética , Transcriptoma/genética , Animais , Modelos Animais de Doenças , Regulação para Baixo/genética , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Insetos , Doenças das Plantas/microbiologia , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Regulação para Cima/genética , Virulência/genética , Zea mays/microbiologia
15.
PLoS One ; 13(7): e0199169, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29966003

RESUMO

Aspergillus flavus is a saprophytic fungus that infects corn, peanuts, tree nuts and other agriculturally important crops. Once the crop is infected the fungus has the potential to secrete one or more mycotoxins, the most carcinogenic of which is aflatoxin. Aflatoxin contaminated crops are deemed unfit for human or animal consumption, which results in both food and economic losses. Within A. flavus, two morphotypes exist: the S strains (small sclerotia) and L strains (large sclerotia). Significant morphological and physiological differences exist between the two morphotypes. For example, the S-morphotypes produces sclerotia that are smaller (< 400 µm), greater in quantity, and contain higher concentrations of aflatoxin than the L-morphotypes (>400 µm). The morphotypes also differ in pigmentation, pH homeostasis in culture and the number of spores produced. Here we report the first full genome sequence of an A. flavus S morphotype, strain AF70. We provide a comprehensive comparison of the A. flavus S-morphotype genome sequence with a previously sequenced genome of an L-morphotype strain (NRRL 3357), including an in-depth analysis of secondary metabolic clusters and the identification SNPs within their aflatoxin gene clusters.


Assuntos
Aspergillus flavus/genética , Genoma Fúngico/genética , Doenças das Plantas/genética , Esporos Fúngicos/genética , Aflatoxinas/genética , Aflatoxinas/toxicidade , Arachis/microbiologia , Aspergillus flavus/classificação , Aspergillus flavus/patogenicidade , Produtos Agrícolas/genética , Produtos Agrícolas/microbiologia , Nozes/microbiologia , Doenças das Plantas/microbiologia , Esporos Fúngicos/patogenicidade , Zea mays/microbiologia
16.
Front Microbiol ; 8: 1661, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28932211

RESUMO

Pneumococcal pneumonia has decreased significantly since the implementation of the pneumococcal conjugate vaccine (PCV), nevertheless, in many developing countries pneumonia mortality in infants remains high. We have undertaken a study of the nasopharyngeal (NP) microbiome during the first year of life in infants from The Philippines and South Africa. The study entailed the determination of the Streptococcus sp. carriage using a lytA qPCR assay, whole metagenomic sequencing, and in silico serotyping of Streptococcus pneumoniae, as well as 16S rRNA amplicon based community profiling. The lytA carriage in both populations increased with infant age and lytA+ samples ranged from 24 to 85% of the samples at each sampling time point. We next developed informatic tools for determining Streptococcus community composition and pneumococcal serotype from metagenomic sequences derived from a subset of longitudinal lytA-positive Streptococcus enrichment cultures from The Philippines (n = 26 infants, 50% vaccinated) and South African (n = 7 infants, 100% vaccinated). NP samples from infants were passaged in enrichment media, and metagenomic DNA was purified and sequenced. In silico capsular serotyping of these 51 metagenomic assemblies assigned known serotypes in 28 samples, and the co-occurrence of serotypes in 5 samples. Eighteen samples were not typeable using known serotypes but did encode for capsule biosynthetic cluster genes similar to non-encapsulated reference sequences. In addition, we performed metagenomic assembly and 16S rRNA amplicon profiling to understand co-colonization dynamics of Streptococcus sp. and other NP genera, revealing the presence of multiple Streptococcus species as well as potential respiratory pathogens in healthy infants. A range of virulence and drug resistant elements were identified as circulating in the NP microbiomes of these infants. This study revealed the frequent co-occurrence of multiple S. pneumoniae strains along with Streptococcus sp. and other potential pathogens such as S. aureus in the NP microbiome of these infants. In addition, the in silico serotype analysis proved powerful in determining the serotypes in S. pneumoniae carriage, and may lead to developing better targeted vaccines to prevent invasive pneumococcal disease (IPD) in these countries. These findings suggest that NP colonization by S. pneumoniae during the first years of life is a dynamic process involving multiple serotypes and species.

17.
Open Forum Infect Dis ; 3(3): ofw120, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27703990

RESUMO

We used ribonucleic acid sequencing to profile Candida albicans transcription within biliary fluid from a patient with cholangitis; samples were collected before and after treatment with fluconazole and drainage. Candida albicans transcriptomes at the infection site distinguished treated from untreated cholangitis. After treatment, 1131 C. albicans genes were differentially expressed in biliary fluid. Up-regulated genes were enriched in hyphal growth, cell wall organization, adhesion, oxidation reduction, biofilm, and fatty acid and ergosterol biosynthesis. This is the first study to define Candida global gene expression during deep-seated human infection. Successful treatment of cholangitis induced C. albicans genes involved in fluconazole responses and pathogenesis.

18.
J Womens Health (Larchmt) ; 25(11): 1086-1096, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27285829

RESUMO

Urologic and kidney problems are common in women across their life span and affect their daily life, including physical activity, sexual relations, social life, and future health. Urological health in women is still understudied and the underlying mechanisms of female urological dysfunctions are not fully understood. The Society for Women's Health Research (SWHR®) recognized the need to have a roundtable discussion where researchers and clinicians would define the current state of knowledge, gaps, and recommendations for future research directions to transform women's urological health. This report summarizes the discussions, which focused on epidemiology, clinical presentation, basic science, prevention strategies, and efficacy of current therapies. Experts around the table agreed on a set of research, education, and policy recommendations that have the potential to dramatically increase awareness and improve women's urological health at all stages of life.


Assuntos
Envelhecimento , Doenças Urológicas/epidemiologia , Saúde da Mulher , Feminino , Humanos , Guias de Prática Clínica como Assunto , Relatório de Pesquisa , Sociedades Médicas , Estados Unidos , Doenças Urológicas/fisiopatologia , Doenças Urológicas/terapia , Urologia
19.
Front Microbiol ; 6: 1338, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26696964

RESUMO

Bacterial persistence due to antibiotic tolerance is a critical aspect of antibiotic treatment failure, disease latency, and chronic or reemergent infections. The levels of persisters is especially notable for the opportunistic Gram-negative pathogens from the Burkholderia and Pseudomonas genera. We examined the rate of drug tolerant persisters in Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia cepacia complex organisms, and Pseudomonas aeruginosa at mid-log growth in LB broth culture. We found that a fraction of the antibiotic-sensitive cells from every species were tolerant to a 24 h high-dose antibiotic challenge. All tested Burkholderia strains demonstrated a drug tolerant persister population at a rate that was at least 100-500 times higher than P. aeruginosa. When challenged with at least a 10X minimum inhibitory concentration (MIC) 24 h exposure to three different antibiotics with different modes of action we found that in B. pseudomallei Bp82 each of the tree antibiotics revealed different persister fractions at each of two different growth states. This observation suggests that our assay is detecting heterogeneous persister subpopulations. Persistence in B. pseudomallei Bp82 was highly dependent on growth stage, with a surprisingly high persister fraction of >64% of the late stationary phase cells being antibiotic tolerant to 100XMIC cefotaxime. Adaptation of B. pseudomallei to distilled water storage resulted in a population of drug tolerant cells up to 100% of the non-drug-challenged viable cell count in the same cefotaxime assay. Cultivation of B. pseudomallei with a sub-inhibitory concentration of several antibiotics resulted in altered persister fractions within the population relative to cultures lacking the antibiotic. Our study provides insight into the sensitivity of the persister fraction within the population of B. pseudomallei due to environmental variables and suggests diversity within the persister population revealed by different challenge antibiotics.

20.
Genome Announc ; 3(2)2015 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-25792043

RESUMO

Bordetella hinzii is a Gram-negative bacterium known to infect poultry, humans, rabbits, and rodents. It is an opportunistic pathogen in immunocompromised humans, and some strains cause mild to moderate respiratory disease in turkeys. Little is known as to the degree of genetic diversity within the species or the genetic basis for virulence. Here, we report the genome sequences of six isolates of B. hinzii acquired from humans, rabbits, or turkeys. These data provide a framework for refining the population structure of the genus, establishing relationships among genetically distinct isolates, and developing an understanding of the possible virulence mechanisms of the bacterium.

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