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1.
PLoS One ; 17(12): e0278206, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36584052

RESUMO

"Candidatus Berkiella cookevillensis" (strain CC99) and "Candidatus Berkiella aquae" (strain HT99), belonging to the Coxiellaceae family, are gram-negative bacteria isolated from amoebae in biofilms present in human-constructed water systems. Both bacteria are obligately intracellular, requiring host cells for growth and replication. The intracellular bacteria-containing vacuoles of both bacteria closely associate with or enter the nuclei of their host cells. In this study, we analyzed the genome sequences of CC99 and HT99 to better understand their biology and intracellular lifestyles. The CC99 genome has a size of 2.9Mb (37.9% GC) and contains 2,651 protein-encoding genes (PEGs) while the HT99 genome has a size of 3.6Mb (39.4% GC) and contains 3,238 PEGs. Both bacteria encode high proportions of hypothetical proteins (CC99: 46.5%; HT99: 51.3%). The central metabolic pathways of both bacteria appear largely intact. Genes for enzymes involved in the glycolytic pathway, the non-oxidative branch of the phosphate pathway, the tricarboxylic acid pathway, and the respiratory chain were present. Both bacteria, however, are missing genes for the synthesis of several amino acids, suggesting reliance on their host for amino acids and intermediates. Genes for type I and type IV (dot/icm) secretion systems as well as type IV pili were identified in both bacteria. Moreover, both bacteria contain genes encoding large numbers of putative effector proteins, including several with eukaryotic-like domains such as, ankyrin repeats, tetratricopeptide repeats, and leucine-rich repeats, characteristic of other intracellular bacteria.


Assuntos
Amoeba , Coxiellaceae , Humanos , Genômica , Amoeba/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
2.
Front Cell Infect Microbiol ; 11: 635673, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33912474

RESUMO

Acinetobacter baumannii has been recognized as a critical pathogen that causes severe infections worldwide not only because of the emergence of extensively drug-resistant (XDR) derivatives, but also because of its ability to persist in medical environments and colonize compromised patients. While there are numerous reports describing the mechanisms by which this pathogen acquires resistance genes, little is known regarding A. baumannii's virulence functions associated with rare manifestations of infection such as necrotizing fasciitis, making the determination and implementation of alternative therapeutic targets problematic. To address this knowledge gap, this report describes the analysis of the NFAb-1 and NFAb-2 XDR isolates, which were obtained at two time points during a fatal case of necrotizing fasciitis, at the genomic and functional levels. The comparative genomic analysis of these isolates with the ATCC 19606T and ATCC 17978 strains showed that the NFAb-1 and NFAb-2 isolates are genetically different from each other as well as different from the ATCC 19606T and ATCC 17978 clinical isolates. These genomic differences could be reflected in phenotypic differences observed in these NFAb isolates. Biofilm, cell viability and flow cytometry assays indicate that all tested strains caused significant decreases in A549 human alveolar epithelial cell viability with ATCC 17978, NFAb-1 and NFAb-2 producing significantly less biofilm and significantly more hemolysis and capacity for intracellular invasion than ATCC 19606T. NFAb-1 and NFAb-2 also demonstrated negligible surface motility but significant twitching motility compared to ATCC 19606T and ATCC 17978, likely due to the presence of pili exceeding 2 µm in length, which are significantly longer and different from those previously described in the ATCC 19606T and ATCC 17978 strains. Interestingly, infection with cells of the NFAb-1 isolate, which were obtained from a premortem blood sample, lead to significantly higher mortality rates than NFAb-2 bacteria, which were obtained from postmortem tissue samples, when tested using the Galleria mellonella in vivo infection model. These observations suggest potential changes in the virulence phenotype of the A. baumannii necrotizing fasciitis isolates over the course of infection by mechanisms and cell processes that remain to be identified.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Fasciite Necrosante , Antibacterianos , Biofilmes , Genômica , Humanos , Fenótipo
3.
Curr Res Food Sci ; 3: 207-216, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32914137

RESUMO

Polysaccharides isolated from Panax quinquefolius roots are widely used as nutraceuticals due to their immunomodulatory properties. Despite their popularity, several challenges exist in isolating ginseng root polysaccharides such as batch-to-batch structural inconsistencies and bacterial endotoxin contamination. A plant tissue culture-based platform offers a potential solution to isolate natural polysaccharide fractions with consistent chemical characteristics and reduced endotoxin content. In this study, an acidic polysaccharide fraction (AGC3) with immunomodulatory properties was isolated from Panax quinquefolius suspension cultures. The heterogeneous fraction (molecular weight: 4.81 and 32.14 kDa), purified by anion exchange chromatography, was predominantly composed of galactose (>60%) along with the presence of rhamnose, arabinose, glucose, glucuronic acid and galacturonic acid. The major glycosidic linkages were found to be t-Galp (47.7%), 4-Galp (15.6%), 2,4-Rhap (8.1%), 6-Galp (8.1%) and 4-GalAp (6.8%). Structural analyses indicated the presence of a pectic rhamnogalacturonan I polysaccharide in AGC3. AGC3 significantly (p < 0.05) stimulated RAW 264.7 murine macrophage cells and primary murine splenocytes by enhancing the production of several immunomodulatory mediators such as IL-6, TNF-α, GM-CSF and MCP-1. The results also indicated the putative roles of NF-κB (p65/RelA) and MAPK (p38) signaling pathways in the immunostimulatory response. Additionally, AGC3 induced murine splenocyte proliferation, another major indicator of immunostimulation. Overall, AGC3 has the potential to be used as an immunostimulatory nutraceutical.

4.
Microbiol Resour Announc ; 9(13)2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32217671

RESUMO

Carbapenem-resistant Acinetobacter baumannii is a bacterial pathogen with serious implications for human health and is recognized as an urgent threat by the Centers for Disease Control and Prevention (CDC). Total DNA from two A. baumannii clinical isolates collected over 3 days from a fatal case of necrotizing fasciitis has been sequenced to >30× coverage.

5.
PLoS One ; 14(12): e0226068, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31825988

RESUMO

Every year, more than 250,000 invasive candidiasis infections are reported with 50,000 deaths worldwide. The limited number of antifungal agents necessitates the need for alternative antifungals with potential novel targets. The 2-benzylidenebenzofuran-3-(2H)-ones have become an attractive scaffold for antifungal drug design. This study aimed to determine the antifungal activity of a synthetic aurone compound and characterize its mode of action. Using the broth microdilution method, aurone SH1009 exhibited inhibition against C. albicans, including resistant isolates, as well as C. glabrata, and C. tropicalis with IC50 values of 4-29 µM. Cytotoxicity assays using human THP-1, HepG2, and A549 human cell lines showed selective toxicity toward fungal cells. The mode of action for SH1009 was characterized using chemical-genetic interaction via haploinsufficiency (HIP) and homozygous (HOP) profiling of a uniquely barcoded Saccharomyces cerevisiae mutant collection. Approximately 5300 mutants were competitively treated with SH1009 followed by DNA extraction, amplification of unique barcodes, and quantification of each mutant using multiplexed next-generation sequencing. Barcode post-sequencing analysis revealed 238 sensitive and resistant mutants that significantly (FDR P values ≤ 0.05) responded to aurone SH1009. The enrichment analysis of KEGG pathways and gene ontology demonstrated the cell cycle pathway as the most significantly enriched pathway along with DNA replication, cell division, actin cytoskeleton organization, and endocytosis. Phenotypic studies of these significantly enriched responses were validated in C. albicans. Flow cytometric analysis of SH1009-treated C. albicans revealed a significant accumulation of cells in G1 phase, indicating cell cycle arrest. Fluorescence microscopy detected abnormally interrupted actin dynamics, resulting in enlarged, unbudded cells. RT-qPCR confirmed the effects of SH1009 in differentially expressed cell cycle, actin polymerization, and signal transduction genes. These findings indicate the target of SH1009 as a cell cycle-dependent organization of the actin cytoskeleton, suggesting a novel mode of action of the aurone compound as an antifungal inhibitor.


Assuntos
Antifúngicos/farmacologia , Benzofuranos/farmacologia , Candida albicans/efeitos dos fármacos , Citoesqueleto de Actina/efeitos dos fármacos , Antifúngicos/química , Benzofuranos/química , Candida albicans/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Desenho de Fármacos , Farmacorresistência Fúngica/genética , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Ontologia Genética , Humanos , Testes de Sensibilidade Microbiana , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento
6.
BMC Genomics ; 20(1): 788, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664902

RESUMO

BACKGROUND: Diverse microbial communities colonizing the intestine of fish contribute to their growth, digestion, nutrition, and immune function. We hypothesized that fecal samples representing the gut microbiota of rainbow trout could be associated with differential growth rates observed in fish breeding programs. If true, harnessing the functionality of this microbiota can improve the profitability of aquaculture. The first objective of this study was to test this hypothesis if gut microbiota is associated with fish growth rate (body weight). Four full-sibling families were stocked in the same tank and fed an identical diet. Two fast-growing and two slow-growing fish were selected from each family for 16S rRNA microbiota profiling. Microbiota diversity varies with different DNA extraction methods. The second objective of this study was to compare the effects of five commonly used DNA extraction methods on the microbiota profiling and to determine the most appropriate extraction method for this study. These methods were Promega-Maxwell, Phenol-chloroform, MO-BIO, Qiagen-Blood/Tissue, and Qiagen-Stool. Methods were compared according to DNA integrity, cost, feasibility and inter-sample variation based on non-metric multidimensional scaling ordination (nMDS) clusters. RESULTS: Differences in DNA extraction methods resulted in significant variation in the identification of bacteria that compose the gut microbiota. Promega-Maxwell had the lowest inter-sample variation and was therefore used for the subsequent analyses. Beta diversity of the bacterial communities showed significant variation between breeding families but not between the fast- and slow-growing fish. However, an indicator analysis determined that cellulose, amylose degrading and amino acid fermenting bacteria (Clostridium, Leptotrichia, and Peptostreptococcus) are indicator taxa of the fast-growing fish. In contrary, pathogenic bacteria (Corynebacterium and Paeniclostridium) were identified as indicator taxa for the slow-growing fish. CONCLUSION: DNA extraction methodology should be carefully considered for accurate profiling of the gut microbiota. Although the microbiota was not significantly different between the fast- and slow-growing fish groups, some bacterial taxa with functional implications were indicative of fish growth rate. Further studies are warranted to explore how bacteria are transmitted and potential usage of the indicator bacteria of fast-growing fish for development of probiotics that may improve fish health and growth.


Assuntos
Microbioma Gastrointestinal , Oncorhynchus mykiss/microbiologia , Animais , DNA/isolamento & purificação , Fezes/microbiologia , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/crescimento & desenvolvimento
7.
Front Microbiol ; 10: 1599, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31396168

RESUMO

Acinetobacter baumannii A118, a strain isolated from the blood of an infected patient, is naturally competent and unlike most clinical strains, is susceptible to a variety of different antibiotics including those usually used for selection in genetic manipulations. These characteristics make strain A118 a convenient model for genetic studies of A. baumannii. To identify potential virulence factors, its complete genome was analyzed and compared to other A. baumannii genomes. A. baumannii A118 includes gene clusters coding for the acinetobactin and baumannoferrin iron acquisition systems. Iron-regulated expression of the BauA outer membrane receptor for ferric-acinetobactin complexes was confirmed as well as the utilization of acinetobactin. A. baumannii A118 also possesses the feoABC genes, which code for the main bacterial ferrous uptake system. The functionality of baumannoferrin was suggested by the ability of A. baumannii A118 culture supernatants to cross feed an indicator BauA-deficient strain plated on iron-limiting media. A. baumannii A118 behaved as non-motile but included the csuA/BABCDE chaperone-usher pilus assembly operon and produced biofilms on polystyrene and glass surfaces. While a known capsular polysaccharide (K) locus was identified, the outer core polysaccharide (OC) locus, which belongs to group B, showed differences with available sequences. Our results show that despite being susceptible to most antibiotics, strain A118 conserves known virulence-related traits enhancing its value as model to study A. baumannii pathogenicity.

8.
Int J Biol Macromol ; 139: 221-232, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31376448

RESUMO

In this study, we propose the use of a plant tissue culture-based system for the production of polysaccharides with consistent chemical characteristics and reduced endotoxin content. Polysaccharides were isolated from suspension cultures of Panax quinquefolius (American ginseng), a widely used medicinal herb. A neutral fraction, AGC1, purified by anion exchange and size exclusion chromatography, displayed immunostimulatory activity in vitro and ex vivo. AGC1 (average molecular weight: 5.2kDa) was predominantly composed of galactose (>60%) along with the presence of several other neutral sugars such as arabinose, xylose, glucose, mannose and rhamnose in minor amounts. The major glycosidic linkages were found to be 3-Galp (48.5%), 3,6-Galp (10.2%), t-Galp (5.2%), 6-Galp (4.4%), 4-Glcp (5.7%), 4-Arap/5-Araf (4.0%) and t-Araf (4.5%). AGC1 significantly (p<0.05) stimulated the expression of a range of proinflammatory mediators in RAW 264.7 murine macrophages such as IL-6, TNF-α, MCP-1 and GM-CSF. Additionally, AGC1 treatment of RAW 264.7 cells stimulated NOS2 gene expression, leading to increased levels of iNOS and downstream NO. Consistent with this, AGC1 was able to act as an immunostimulant in primary murine splenocytes, enhancing cell proliferation, as well as NO and TNF-α production. Our results also indicate the partial role of NF-κB pathway in the immunostimulatory response.


Assuntos
Meios de Cultivo Condicionados/química , Meios de Cultivo Condicionados/farmacologia , Panax/química , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Animais , Células Cultivadas , Citocinas/metabolismo , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Imunomodulação/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Peso Molecular , Óxido Nítrico/metabolismo , Panax/citologia , Panax/metabolismo , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Polissacarídeos/isolamento & purificação , Células RAW 264.7
9.
Int J Biol Macromol ; 133: 76-85, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30981779

RESUMO

Frankincense has a long history in religious, cultural, and medicinal use. In this study polysaccharides were extracted from frankincense from Boswellia carterii. The polysaccharides were purified by anion exchange chromatography on a DEAE-Sepharose Fast Flow 16/10 FPLC column. Six fractions were obtained and the three most active immunomodulatory fractions were further purified by size exclusion chromatography on a Superdex-200 column. The composition showed the monosaccharides present were predominantly galactose, arabinose, and glucuronic acid along with small amounts of rhamnose and glucose. The monosaccharide composition and glycosyl linkage analysis revealed the polysaccharides belong to the type II arabinogalactans. Fourier-transform infrared spectroscopy and bicinchoninic acid assay showed that the amount of protein in the samples was <1 wt%. One-dimensional 1H NMR were consistent with high molecular weight compounds. The monosaccharides were primarily in the ß conformation. The three fractions exhibited an immunostimulatory effect on RAW 264.7 murine macrophage cells. The most active immunostimulatory fraction FA2, stimulated a range of pro-inflammatory mediators including iNOS, NO, TNF-α, and IL-6 in RAW 264.7 cells. The fractions were effective in proliferating primary murine splenocytes. The results indicate that the polysaccharides isolated from frankincense have the potential to be used as an immunological stimulant or nutraceutical.


Assuntos
Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/farmacologia , Franquincenso/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Adjuvantes Imunológicos/isolamento & purificação , Animais , Glicosilação , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Peso Molecular , Óxido Nítrico/metabolismo , Polissacarídeos/isolamento & purificação , Células RAW 264.7 , Fator de Necrose Tumoral alfa/metabolismo
10.
Artigo em Inglês | MEDLINE | ID: mdl-30373804

RESUMO

Stagnation in antimicrobial development has led to a serious threat to public health because some Acinetobacter baumannii infections have become untreatable. New therapeutics with alternative mechanisms of action to combat A. baumannii are therefore necessary to treat these infections. To this end, the virulence of A. baumannii isolates with various antimicrobial susceptibilities was assessed when the isolates were treated with miltefosine, a phospholipase C inhibitor. Phospholipase C activity is a contributor to A. baumannii virulence associated with hemolysis, cytolysis of A549 human alveolar epithelial cells, and increased mortality in the Galleria mellonella experimental infection model. While the effects on bacterial growth were variable among strains, miltefosine treatment significantly reduced both the hemolytic and cytolytic activity of all treated A. baumannii strains. Additionally, scanning electron microscopy of polarized A549 cells infected with bacteria of the A. baumannii ATCC 19606T strain or the AB5075 multidrug-resistant isolate showed a decrease in A549 cell damage with a concomitant increase in the presence of A549 surfactant upon administration of miltefosine. The therapeutic ability of miltefosine was further supported by the results of G. mellonella infections, wherein miltefosine treatment of animals infected with ATCC 19606T significantly decreased mortality. These data demonstrate that inhibition of phospholipase C activity results in the overall reduction of A. baumannii virulence in both in vitro and in vivo models, making miltefosine a viable option for the treatment of A. baumannii infections, particularly those caused by multidrug-resistant isolates.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/patogenicidade , Antibacterianos/uso terapêutico , Fosforilcolina/análogos & derivados , Células A549 , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Animais , Linhagem Celular , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Testes de Sensibilidade Microbiana , Mariposas/microbiologia , Fosforilcolina/uso terapêutico , Fosfolipases Tipo C/antagonistas & inibidores , Virulência/efeitos dos fármacos
11.
Int J Antimicrob Agents ; 51(5): 752-761, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29410367

RESUMO

The aminoglycoside, 6'-N-acetyltransferase type Ib [AAC(6')-Ib] is the most widely distributed enzyme among AAC(6')-I-producing Gram-negative pathogens and confers resistance to clinically relevant aminoglycosides, including amikacin. This enzyme is therefore an ideal target for enzymatic inhibitors that could overcome resistance to aminoglycosides. The search for inhibitors was carried out using mixture-based combinatorial libraries, the scaffold ranking approach, and the positional scanning strategy. A library with high inhibitory activity had pyrrolidine pentamine scaffold and was selected for further analysis. This library contained 738,192 compounds with functionalities derived from 26 different amino acids (R1, R2 and R3) and 42 different carboxylic acids (R4) in four R-group functionalities. The most active compounds all contained S-phenyl (R1 and R3) and S-hydromethyl (R2) functionalities at three locations and differed at the R4 position. The compound containing 3-phenylbutyl at R4 (compound 206) was a robust enzymatic inhibitor in vitro, in combination with amikacin it potentiated the inhibition of growth of three resistant bacteria in culture, and it improved survival when used as treatment of Galleria mellonella infected with aac(6')-Ib-harboring Klebsiella pneumoniae and Acinetobacter baumannii strains.


Assuntos
Acetiltransferases/antagonistas & inibidores , Antibacterianos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Aminoácidos/química , Animais , Antibacterianos/química , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli/efeitos dos fármacos , Células HEK293 , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Pirrolidinas/química , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade
12.
PLoS One ; 13(1): e0190599, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29309434

RESUMO

The capacity of Acinetobacter baumannii to persist and cause infections depends on its interaction with abiotic and biotic surfaces, including those found on medical devices and host mucosal surfaces. However, the extracellular stimuli affecting these interactions are poorly understood. Based on our previous observations, we hypothesized that mucin, a glycoprotein secreted by lung epithelial cells, particularly during respiratory infections, significantly alters A. baumannii's physiology and its interaction with the surrounding environment. Biofilm, virulence and growth assays showed that mucin enhances the interaction of A. baumannii ATCC 19606T with abiotic and biotic surfaces and its cytolytic activity against epithelial cells while serving as a nutrient source. The global effect of mucin on the physiology and virulence of this pathogen is supported by RNA-Seq data showing that its presence in a low nutrient medium results in the differential transcription of 427 predicted protein-coding genes. The reduced expression of ion acquisition genes and the increased transcription of genes coding for energy production together with the detection of mucin degradation indicate that this host glycoprotein is a nutrient source. The increased expression of genes coding for adherence and biofilm biogenesis on abiotic and biotic surfaces, the degradation of phenylacetic acid and the production of an active type VI secretion system further supports the role mucin plays in virulence. Taken together, our observations indicate that A. baumannii recognizes mucin as an environmental signal, which triggers a response cascade that allows this pathogen to acquire critical nutrients and promotes host-pathogen interactions that play a role in the pathogenesis of bacterial infections.


Assuntos
Acinetobacter baumannii/patogenicidade , Genes Bacterianos , Mucinas/metabolismo , Virulência/genética , Células A549 , Acinetobacter baumannii/genética , Acinetobacter baumannii/crescimento & desenvolvimento , Biofilmes , Interações Hospedeiro-Patógeno , Humanos , Microscopia Eletrônica de Transmissão , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNA , Transcriptoma
13.
Genome Announc ; 5(18)2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28473387

RESUMO

Gardnerella vaginalis is a Gram-variable bacterium associated with bacterial vaginosis, a common vaginal inflammation in women of reproductive age. This study reports the whole-genome sequencing for the clinical isolate strain ATCC 49145. The draft genome is composed of 21 contigs containing 1,325 protein-coding sequences, 45 tRNAs and a single tmRNA (SsrA).

14.
Artigo em Inglês | MEDLINE | ID: mdl-28421168

RESUMO

Genetic and functional studies showed that some components of the Acinetobacter baumannii ATCC 17978 A1S_0112-A1S_0119 gene cluster are critical for biofilm biogenesis and surface motility. Recently, our group has shown that the A1S_0114 gene was involved in biofilm formation, a process related with pathogenesis. Confirming our previous results, microscopy images revealed that the ATCC 17978 Δ0114 derivative lacking this gene was unable to form a mature biofilm structure. Therefore, other bacterial phenotypes were analyzed to determine the role of this gene in the pathogenicity of A. baumannii ATCC 17978. The interaction of the ATCC 17978 parental strain and the Δ0114 mutant with A549 human alveolar epithelial cells was quantified revealing that the A1S_0114 gene was necessary for proper attachment to A549 cells. This dependency correlates with the negative effect of the A1S_0114 deletion on the expression of genes coding for surface proteins and pili-assembly systems, which are known to play a role in adhesion. Three different experimental animal models, including vertebrate and invertebrate hosts, confirmed the role of the A1S_0114 gene in virulence. All of the experimental infection assays indicated that the virulence of the ATCC 17978 was significantly reduced when this gene was inactivated. Finally, we discovered that the A1S_0114 gene was involved in the production of a small lipopeptide-like compound herein referred to as acinetin 505 (Ac-505). Ac-505 was isolated from ATCC 17978 spent media and its chemical structure was interpreted by mass spectrometry. Overall, our observations provide novel information on the role of the A1S_0114 gene in A. baumannii's pathobiology and lay the foundation for future work to determine the mechanisms by which Ac-505, or possibly an Ac-505 precursor, could execute critical functions as a secondary metabolite.


Assuntos
Acinetobacter baumannii/genética , Acinetobacter baumannii/patogenicidade , Aderência Bacteriana , Células Epiteliais/microbiologia , Interações Hospedeiro-Patógeno , Fatores de Virulência/genética , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/patologia , Acinetobacter baumannii/fisiologia , Adesinas Bacterianas/genética , Animais , Biofilmes/crescimento & desenvolvimento , Caenorhabditis elegans , Linhagem Celular , Modelos Animais de Doenças , Feminino , Deleção de Genes , Humanos , Lepidópteros , Camundongos Endogâmicos BALB C , Microscopia , Virulência
15.
Int Immunopharmacol ; 43: 116-128, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27988459

RESUMO

Suppressing cytokine responses has frequently been shown to have promising therapeutic effects for many chronic inflammatory and autoimmune diseases. However, the severe side effects associated with the long-term use of current treatments, such as allergic reactions and increased risk of stroke, have focused attention towards the targeting of intracellular signaling mechanisms, such as NF-κB, that regulate inflammation. We synthesized a series of non-natural aurone derivatives and investigated their ability to suppress pro-inflammatory signaling in human monocyte (THP-1) and murine macrophage-like (RAW 267.4) cell lines. One of these derivatives, (Z)-2-((5-(hydroxymethyl) furan-2-yl) methylene) benzofuran-3(2H)-one (aurone 1), was found to inhibit LPS-induced secretion of the pro-inflammatory cytokines, tumor-necrosis factor α (TNFα), interleukin 1ß (IL-1ß), and IL-8 by THP-1 cells. To investigate the mechanism, we probed the effect of aurone 1 on LPS-induced MAPK and NF-κB signaling in both THP-1 and RAW264.7. While aurone 1 pre-treatment had no effect on the phosphorylation of ERK, JNK, or p38 MAPK, it strongly suppressed activation of IKK-ß, as indicated by attenuation of Ser176/180 phosphorylation, resulting in decreased phosphorylation of p65 (ser536) as well as phosphorylation (ser32) and degradation of IκBα. Consistent with this, aurone 1 significantly reduced LPS-stimulated nuclear translocation of p65-containing NF-κB transcription factors and expression of an mCherry reporter of TNFα gene transactivation in RAW264.7 cells. Inhibition of TNFα expression at the transcription level was also demonstrated in THP-1 by qRT-PCR. In addition to its effects on cytokine expression, aurone 1 pre-treatment decreased expression of iNOS, a bona fide NF-κB target gene and marker of macrophage M1 polarization, resulting in decreased NO production in RAW264.7 cells. Together, these data indicate that aurone 1 may have the potential to function as a pharmacological agent for the treatment of chronic inflammation disorders.


Assuntos
Anti-Inflamatórios/uso terapêutico , Benzofuranos/farmacologia , Inflamação/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Monócitos/efeitos dos fármacos , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Benzofuranos/síntese química , Citocinas/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos/imunologia , Macrófagos/imunologia , Camundongos , Monócitos/imunologia , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genética
16.
PLoS One ; 11(11): e0167068, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27875572

RESUMO

Acinetobacter baumannii is an opportunistic Gram-negative pathogen that causes a wide range of infections including pneumonia, septicemia, necrotizing fasciitis and severe wound and urinary tract infections. Analysis of A. baumannii representative strains grown in Chelex 100-treated medium for hemolytic activity demonstrated that this pathogen is increasingly hemolytic to sheep, human and horse erythrocytes, which interestingly contain increasing amounts of phosphatidylcholine in their membranes. Bioinformatic, genetic and functional analyses of 19 A. baumannii isolates showed that the genomes of each strain contained two phosphatidylcholine-specific phospholipase C (PC-PLC) genes, which were named plc1 and plc2. Accordingly, all of these strains were significantly hemolytic to horse erythrocytes and their culture supernatants tested positive for PC-PLC activity. Further analyses showed that the transcriptional expression of plc1 and plc2 and the production of phospholipase and thus hemolytic activity increased when bacteria were cultured under iron-chelation as compared to iron-rich conditions. Testing of the A. baumannii ATCC 19606T plc1::aph-FRT and plc2::aph isogenic insertion derivatives showed that these mutants had a significantly reduced PC-PLC activity as compared to the parental strain, while testing of plc1::ermAM/plc2::aph demonstrated that this double PC-PLC isogenic mutant expressed significantly reduced cytolytic and hemolytic activity. Interestingly, only plc1 was shown to contribute significantly to A. baumannii virulence using the Galleria mellonella infection model. Taken together, our data demonstrate that both PLC1 and PLC2, which have diverged from a common ancestor, play a concerted role in hemolytic and cytolytic activities; although PLC1 seems to play a more critical role in the virulence of A. baumannii when tested in an invertebrate model. These activities would provide access to intracellular iron stores this pathogen could use during growth in the infected host.


Assuntos
Infecções por Acinetobacter/enzimologia , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/patogenicidade , Proteínas de Bactérias/metabolismo , Genoma Bacteriano , Fosfolipases Tipo C/metabolismo , Células A549 , Infecções por Acinetobacter/genética , Acinetobacter baumannii/genética , Animais , Proteínas de Bactérias/genética , Bovinos , Modelos Animais de Doenças , Cavalos , Humanos , Ovinos , Fosfolipases Tipo C/genética
17.
Genome Announc ; 4(4)2016 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-27563036

RESUMO

Acinetobacter baumannii is a Gram-negative bacterium capable of causing hospital-acquired infections that has been grouped with Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as ESKAPE pathogens because of their extensive drug resistance phenotypes and increasing risk to human health. Twenty-four multidrug-resistant A. baumannii strains isolated from wounded military personnel were sequenced and annotated.

18.
Genome Announc ; 4(4)2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27516515

RESUMO

Members of the Escherichia coli bacterial family have been grouped as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens because of their extensive drug resistance phenotypes and increasing threat to human health. The genomes of six extended-spectrum ß-lactamase (ESBL)-producing E. coli strains isolated from wounded military personnel were sequenced and annotated.

19.
Genome Announc ; 4(4)2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27516516

RESUMO

Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work.

20.
Genome Announc ; 4(1)2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26893424

RESUMO

"Candidatus Berkiella cookevillensis" and "Candidatus Berkiella aquae" are obligate intranuclear endosymbionts of freshwater amoebae. Here, we present the draft genome sequences of these two bacteria, with total sizes of 2,990,361 bp and 3,626,027 bp, respectively.

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