Oliveira D.L.,Institute Microbiologia Prof Paulo Of Goes |
Freire-de-Lima C.G.,Federal University of Rio de Janeiro |
Nosanchuk J.D.,Yeshiva University |
Casadevall A.,Yeshiva University |
And 2 more authors.
Infection and Immunity | Year: 2010
Cryptococcus neoformans and distantly related fungal species release extracellular vesicles that traverse the cell wall and contain a varied assortment of components, some of which have been associated with virulence. Previous studies have suggested that these extracellular vesicles are produced in vitro and during animal infection, but the role of vesicular secretion during the interaction of fungi with host cells remains unknown. In this report, we demonstrate by fluorescence microscopy that mammalian macrophages can incorporate extracellular vesicles produced by C. neoformans. Incubation of cryptococcal vesicles with murine macrophages resulted in increased levels of extracellular tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), and transforming growth factor β (TGF-β). Vesicle preparations also resulted in a dose-dependent stimulation of nitric oxide production by phagocytes, suggesting that vesicle components stimulate macrophages to produce antimicrobial compounds. Treated macrophages were more effective at killing C. neoformans yeast. Our results indicate that the extracellular vesicles of C. neoformans can stimulate macrophage function, apparently activating these phagocytic cells to enhance their antimicrobial activity. These results establish that cryptococcal vesicles are biologically active. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Grigorevski-Lima A.L.,Institute Microbiologia Prof Paulo Of Goes |
De Oliveira M.M.Q.,Institute Microbiologia Prof Paulo Of Goes |
Do Nascimento R.P.,Federal University of Rio de Janeiro |
Da Silva Bon E.P.,University of Sao Paulo |
Coelho R.R.R.,Institute Microbiologia Prof Paulo Of Goes
Applied Biochemistry and Biotechnology | Year: 2013
Trichoderma atroviride 676 was studied to evaluate its efficiency in the production of some lignocellulolytic enzymes, using lignocellulosic residual biomass. Best results were obtained when 3.0 % (w/v) untreated sugarcane bagasse was used (61.3 U mL-1 for xylanase, 1.9 U mL-1 for endoglucanase, 0.25 U mL-1 for FPase, and 0.17 U mL-1 for β- glucosidase) after 3-4 days fermentation. The maximal enzymatic activity for endoglucanase, FPase, and xylanase were observed at 50-60 °C and pH4.0-5.0, whereas thermal stability at 50 °C (CMCase and FPase) or 40 °C (xylanase) was obtained after 8 h. Zymograms have shown two bands of 104 and 200 kDa for endoglucanases and three bands for xylanase (23, 36, and 55.7 kDa). The results obtained with T. atroviride strain 676 were comparable to those obtained with the cellulolytic strain Trichoderma reesei RUT-C30, indicating, in the studied conditions, its great potential for biotechnological application, especially lignocellulose biomass hydrolysis. © Springer Science+Business Media New York 2013.
Pereira E.M.,Federal University of Rio de Janeiro |
Oliveira F.L.F.,Federal University of Rio de Janeiro |
Schuenck R.P.,Federal University of Rio de Janeiro |
Zoletti G.O.,Federal University of Rio de Janeiro |
And 2 more authors.
FEMS Immunology and Medical Microbiology | Year: 2010
Staphylococcus lugdunensis are unusually virulent coagulase-negative staphylococci associated with skin infections and endocarditis. We developed an accurate and simple PCR assay to identify S. lugdunensis isolates based on detection of the fbl gene, which encodes a fibrinogen-binding protein involved in pathogen adhesion. The PCR assay was established using 16 reference strains of different Staphylococcus species and further validated with a collection of 63 clinical staphylococcal isolates that were also phenotypically characterized. Reliable results for the detection of S. lugdunensis isolates were obtained for 100% of the strains evaluated, indicating that this PCR assay can be used in the routine of microbiology laboratories as one more tool for correct species differentiation. © 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Balassiano I.T.,Institute Microbiologia Prof Paulo Of Goes |
Balassiano I.T.,Instituto Oswaldo Cruz |
Santos-Filho J.D.,Institute Microbiologia Prof Paulo Of Goes |
Vital-Brazil J.M.,Instituto Oswaldo Cruz |
And 6 more authors.
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology | Year: 2011
Clostridium difficile is an important nosocomial enteric pathogen and is the etiological agent of pseudomembranous colites. Recently, the rates of C. difficile infection (CDI) have increased worldwide, but in Brazil few data about this situation and the incidence of clonal types of C. difficile exist. This study aimed to isolate and characterize C. difficile strains from samples obtained of a university hospital (HUCFF) in Rio de Janeiro city, Brazil. CDI was identified by ELISA in 27.1% of HUCFF-in-patients enrolled in the study, and the bacterium was recovered from eight of these fecal samples. All strains, except one, presented tcdA and tcdB genes and presented neither the cdtA and cdtB genes nor any significant deletions in the tcdC gene. All strains were sensitive to metronidazole, vancomycin and moxifloxacin, and resistant to clindamycin, ciprofloxacin and levofloxacin. PCR-ribotyping and PFGE revealed four different clonal types among the isolates. The Brazilian PCR-ribotype 133 accounted for 50% of strains isolated, and PCR-ribotype 233 strains were obtained from 25% of the in-patients. The prevalence and resurgence of the Brazilian PCR-ribotype 133 among the hospitalized patients of HUCFF was established, and cross-infection of different patients associated to the same PCR-ribotypes was detected. Our results emphasize the importance of the diagnosis and control of CDI in order to prevent the emergence of specific clones that can lead to C. difficile-associated outbreaks in Brazilian hospitals. © 2010 Springer Science+Business Media B.V.
Kneipp L.F.,Instituto Oswaldo Cruz |
Alviano C.S.,Institute Microbiologia Prof Paulo Of Goes |
Meyer-Fernandes J.R.,Federal University of Rio de Janeiro |
De Araujo Soares R.M.,Institute Microbiologia Prof Paulo Of Goes
Oral Diseases | Year: 2010
Objective: This study describes the expression of acidic ectophosphatase activity on twenty isolates of C. albicans from oral cavities of HIV-infected children (HIV+) and compares them with fifteen isolates from HIV-negative children (HIV-), as well as the fungal adhesion to epithelial cells and medical records. Methods: The activities were measured in intact cells grown in BHI medium for 48 h at 37°C. Phosphatase activity was assayed at pH 5.5 using 4-methylumbelliferyl phosphate. Yeast adhesion was measured using the MA 104 epithelial cell line. Results: Mean values of ectophosphatase activity were 610.27 ± 166.36 and 241.25 ± 78.96 picomoles 4- methylumbelliferone/h/107 cells for HIV+ and HIV- group, respectively (P = 0.049). No correlation between C. albicans enzyme activity from HIV children with viral load and CD4 percentual was observed. Yeasts with high enzyme activity, isolated from HIV+ children showed greater adherence than yeasts with basal levels of ectophosphatases from HIV- (Spearman correlation, r = 0.8). Surface phosphatase activity was apparently involved in the adhesion to host cells, as the enhanced attachment of C. albicans to host epithelial cells was reversed by pretreatment of yeast with sodium orthovanadate (1 mM), an acid phosphatase inhibitor. Conclusion: These results show that C. albicans from HIV+ has an ectophosphatase activity significantly higher than the other isolates. Yeasts expressing higher levels of surface phosphatase activity showed greater adhesion to epithelial cells. So, the activity of acidic surface phosphatases on these cells may contribute to the early mechanisms required for disease establishment. © 2010 John Wiley & Sons A/S.