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1.
Knowledge concerning the host–Paracoccidioides brasiliensis interactions is abundant. Yet, most of the experimental studies have used yeast cells to prepare the corresponding inoculum.
As these cells do not represent the naturally infecting propagules, the corresponding experiments by-pass the earlier stages
of such interactions. Studies done in patients, who also harbour yeast cells, suffer from the same bias. The review presented
below focuses on the immune responses of BALB/c mice infected with conidia obtained from P. brasiliensis mycelial form cultures, the fungal stage most probably existing in nature. As such, the corresponding experiments would copy
the onset and course of the human infection. A large number of experimental studies done by the CIB Medical and Experimental
Mycology Unit in a period of almost 25 years have been revised and extracted so as to present a comprehensive record on the
immune responses induced when mice are infected intranasally with the conidia. The establishment of this mouse model has permitted
the analysis of the immune responses taking place during the early and late stages post-challenge. This unique model has made
possible to characterize the course of the experimental disease including the inflammatory reaction, the expression of cytokines
and of the various molecules associated to these responses, all of which lead to granuloma formation. The latter structure
serves as a nest for the development of fibrosis. Thus, we have also obtained a glimpse on the complexity that accompanies
the fibrosis, the most common sequelae of paracoccidioidomycosis. Additionally, a concerted effort has been made to appraise
the whole gamut of immune factors and related molecules that directly or indirectly, contribute to shape the pathogenesis
of this Latin American mycosis. 相似文献
2.
Ayako Sano Reiko Tanaka Kazuko Nishimura Cilmery S. Kurokawa Kunie labuki R. Coelho Marcello Franco Mario Rubens Montenegro Makoto Miyaji 《Mycoscience》1997,38(2):117-122
We have studied the physiological and morphological features of 17 isolates ofParacoccidioides brasiliensis in order to define their phenotypes. The isolates were cultured at room temperature on potato dextrose agar (PDA, Difco)
slants for mycelial growth and in 1% dextrose brain heart infusion agar (BHIA, Difco) at 37°C for the study of yeast forms.
Most mycelial and yeast forms grew well between pH 5.6–9.4. In their response to osmotic pressure the isolates were separated
in three groups: intolerant, intermediate and tolerant. They also varied in carbohydrate assimilation tests, which indicated
important metabolic variation. No clear differences were observed in phenol oxidase tests, KNO3, starch, casein and arbutin assimilation tests. Only 1 of the isolates, Bt-19, had gelatinase activity. No correlation was
observed between the above differences and virulence. Two patterns of growth were observed in the mycelial cultures, glabrous
and cottonous, the latter being correlated with increased virulence for ddY mice. Most yeast forms grew as cerebriform colonies,
but Pb-HC and Bt-19 colonies had a cobblestone-like surface. 相似文献
3.
Characteristics of the conidia produced by the mycelial form of Paracoccidioides brasiliensis 总被引:3,自引:0,他引:3
B Bustamante-Simon J G McEwen A M Tabares M Arango A Restrepo-Moreno 《Sabouraudia》1985,23(6):407-414
The sporulation capacities of the mycelial form of Paracoccidioides brasiliensis were determined. Five different culture media were used and four human isolates studied. Conidia were produced in three agar media, namely water-agar, glucose-salts and yeast-extract. Corn meal and Sabouraud dextrose agars failed to induce sporulation. Various types of spores were characterized with peculiar bulging arthroconidia and single-celled, pear-shaped conidia predominating. The size of these conidia varied from 3.6 to 4.6 micron in length. It is concluded that the mycelial form of P. brasiliensis produces characteristic spores if the proper culture media are employed. 相似文献
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6.
Diana Tamayo Orville Hernández Cesar Mu?oz-Cadavid Luz Elena Cano Angel González 《Memórias do Instituto Oswaldo Cruz》2013,108(4):488-493
The infectious process starts with an initial contact between pathogen
and host. We have previously demonstrated that Paracoccidioides
brasiliensis conidia interact with plasma proteins including
fibrinogen, which is considered the major component of the coagulation system.
In this study, we evaluated the in vitro capacity of P.
brasiliensis conidia to aggregate with plasma proteins and
compounds involved in the coagulation system. We assessed the aggregation of
P. brasiliensis conidia after incubation with human serum
or plasma in the presence or absence of anticoagulants, extracellular matrix
(ECM) proteins, metabolic and protein inhibitors, monosaccharides and other
compounds. Additionally, prothrombin and partial thromboplastin times were
determined after the interaction of P. brasiliensis conidia
with human plasma. ECM proteins, monosaccharides and human plasma significantly
induced P. brasiliensis conidial aggregation; however,
anticoagulants and metabolic and protein inhibitors diminished the aggregation
process. The extrinsic coagulation pathway was not affected by the interaction
between P. brasiliensis conidia and plasma proteins, while the
intrinsic pathway was markedly altered. These results indicate that P.
brasiliensis conidia interact with proteins involved in the
coagulation system. This interaction may play an important role in the initial
inflammatory response, as well as fungal disease progression caused by
P. brasiliensis dissemination. 相似文献
7.
Marcello Franco Eduardo Bagagli Marino Cunha Luiz Gastão Chamma Denise Fecchio 《Mycopathologia》1996,135(1):13-19
We investigated the occurrence of antigenic and biochemical variability among Paracoccidioides brasiliensis antigen batches prepared according to the same protocol. Initially (experiment #1), we analyzed two antigen lots of two human isolates (Bt1 & Bt2), cultured in two media (PYG: bactopeptone, yeast extract, glucose; MMM: McVeigh & Morton medium) in SDS-PAGE and in two immunological tests (imunodiffusion-ID and footpad swelling test-FPT). Afterwards (experiment #2), we compared the antigenic profile of three antigen batches from three human isolates (Bt1, Bt2 & Bt3) by two-dimensional immunoelectrophoresis (2 D-IEP) against a reference system for P. brasiliensis antigens. In experiment #1, there were important intra- and inter-strain antigenic differences between batches of the fungal isolates cultured on both media. The block titration of the antigen batches for the immunological tests revealed correlation between protein concentration and biological activity in ID and no correlation in FPT. In experiment #2, the reference system for P. brasiliensis showed 26 antigen peaks. There were important differences between batches prepared from the same isolate and between batches from different isolates. Our data suggested the occurrence of instability in the synthesis of antigenic components by a same P. brasiliensis isolate, under controlled incubation conditions. 相似文献
8.
9.
Serological detection of antibodies against Paracoccidioides brasiliensis in dogs with leishmaniasis
Silveira LH Domingos IH Kouchi K Itano EN Silva EA Landgraf VO Werneck SM Camargo ZP Ono MA 《Mycopathologia》2006,162(5):325-329
The aim of this study was to detect antibodies against Paracoccidioides brasiliensis in dogs seropositive and seronegative for leishmaniasis. Sera from 836 dogs (449 positive and 387 negative to leishmaniasis)
were analysed by ELISA and the immunodiffusion test using gp43 and exoantigen, respectively. The analysis of the 836 serum
samples by ELISA and the immunodiffusion test showed a positivity of 67.8 % and 7.3%, respectively, for P. brasiliensis infection. The dogs positive to leishmaniasis showed a higher reactivity to gp43 (79.9%) and exoantigen (12.7%) than the
negative ones (54.0% and 1.0%, respectively). The higher reactivity to P. brasiliensis antigens may be due to cross-reactivity or a co-infection of dogs by Leishmania and P. brasiliensis. The lower correlation (0.187) observed between reactivity to gp43 and Leishmania antigen reinforces the latter hypothesis. 相似文献
10.
Growth curves,morphology and ultrastructure of ten Paracoccidioides brasiliensis isolates 总被引:1,自引:1,他引:0
Suely Sanae Kashino Vera Lucia Garcia Calich Lucia Mary Singer-Vermes Paulo Alexandre Abrahamsohn Eva Burger 《Mycopathologia》1987,99(2):119-128
The yeast phase of ten P. brasiliensis isolates were studied to characterize their growth pattern, morphology and ultrastructure. Growth curves were determined after counts of total and viable fungi units (FU) during 20 days. Three growth patterns were observed: slow, reaching approximately 10–30× 106 FU/tube (Pb 18, Pb 265 and PB 2); intermediate, reaching 60–150×106 FU/tube (IVIC Pb 9, IVIC Pb 267, Pb SN, Pb Vitor and Pb Campo Grande) and fast, reaching 180–370×106 FU/tube (Pb 2052 and Pb 192). The highest percentage of viable cells occurred on the 6th day of culture for Pb 192, Pb Campo Grande, Pb 2052 and IVIC Pb 9; on the 8th day for Pb Vitor, Pb SN, Pb 18 and IVIC Pb 267; on the 10th day for Pb 265 and on the 12th day of culture for Pb 2. Mean generation times varied from approximately 21.2 (Pb 2052) to 102.6 hours (Pb 265). The isolates showed similar morphology, except IVIC Pb 267 which did not present a typical yeast-phase at 35°C and the two fast-growing isolates (Pb 2052 and Pb 192) that presented smaller cell sizes and less tendency to clump. The ultrastructure of the isolates was similar: the cell walls presented a width of 0.1 to 0.2 °; the mitochondria presented few cristae and had equivalent patterns of distribution and morphology; the endoplasmic reticulum was scanty, presenting narrow cisternae; the vacuoles, empty or filled with electrondense material, were numerous and two to five nuclei with pores were constantly observed. 相似文献
11.
Popi AF Godoy LC Xander P Lopes JD Mariano M 《Microbes and infection / Institut Pasteur》2008,10(7):817-824
Protective immunity in paracoccidioidomycosis is mainly mediated by cellular immunity. The role of B cells in this disease, in particular B-1 cells, is poorly understood. The aim of this study was to characterize the participation of B-1 cells in resistance or susceptibility of BALB/c and BALB/Xid mice to P. brasiliensis (Pb) pulmonary infection. BALB/Xid, which lacks B-1 cells, exhibited higher resistance to infection when compared with BALB/c mice. However, adoptive transfer of B-1 cells to BALB/Xid mice drastically increased the susceptibility of these animals to Pb infection. The fungal burden in BALB/c and B-1-reconstituted BALB/Xid was significantly higher as compared to BALB/Xid strain. Compact, well-organized granulomas were observed in the lungs of BALB/Xid mice, whereas large lesions with necrotic center with a plethora of fungi developed in BALB/c mice. It was also shown that B-1 cells impair phagocytosis of Pb by macrophages in vitro via secretion of IL-10, which was increased upon stimulation with a purified Pb antigen, gp43. Finally, in vivo blockade of IL-10 led to a better control of infection by the highly susceptible B10.A mouse. These findings suggest that B-1 cells play a major role in resistance/susceptibility to Pb infection in murine models, most likely via production of IL-10. 相似文献
12.
Stability of virulence in P. brasiliensis isolates was studied with respect to the in vitro culture history and methods used for storage. Virulence in yeast-form P. brasiliensis isolates was tested in a chronic pulmonary murine model of paracoccidioidomycosis where progression of disease was quantitated in terms of colony forming units recoverable from lungs. Four isolates of P. brasiliensis, including recently isolated from patients or experimental animals, caused chronic progressive disease. Two isolates with a history of subculturing showed attenuation by causing resolving but chronic disease. An attenuated isolate became avirulent subsequent to 15 more years of subculturing. These findings suggest that virulence of P. brasiliensis can be attenuated or lost subsequent to cycles of subculturing over long periods. Our data suggest that the use of fresh P. brasiliensis isolates may be needed to provide reproducible virulence for experimental systems.Abbreviations ATCC
American Type Culture Collection
- CFU
colony-forming units
- LD
Lethal dose
- MMv-M
modified McVeigh Morton
- PMN
polymorphonuclear neutrophil 相似文献
13.
Isolates of Paracoccidioides brasiliensis may vary in virulence according to time of in vitro subcultivation. The present study compared the morphology and pathogenicity to hamsters of two P. brasiliensis isolates: one obtained from human lesions and maintained in the laboratory for several years (Pb-18) and the other isolate
recovered from hamsters inoculated with organ homogenates from armadillos (Pb-T). The microscopic morphology of Pb-18 and
Pb-T showed yeast cells with similar diameter. However, Pb-T produced a significantly higher number of buds per mother cell
than Pb-18. Besides, the mycelial form of Pb-T developed abundant sporulation during 8 weeks of culture which was absent in
the Pb-18 isolate. Virulence studies demonstrated that mortality rates, antibody levels, fungal load and extent of lesions
in the organs were significantly higher in animals infected with Pb-T. The results demonstrated that Pb-T recently isolated
from an animal was more virulent than Pb-18. These differences between the two P. brasillensis isolates may be indicators of virulence attenuation in this fungal species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Almeida AJ Carmona JA Cunha C Carvalho A Rappleye CA Goldman WE Hooykaas PJ Leão C Ludovico P Rodrigues F 《Fungal genetics and biology : FG & B》2007,44(12):1387-1398
We herein report the development of a molecular toolbox for the dimorphic fungus Paracoccidioides brasiliensis, specifically a more efficient transformation and a gene expression system. We evaluated several parameters that influence Agrobacterium tumefaciens-mediated transformation (ATMT), such as co-cultivation conditions and host cell susceptibility. Our results show that cellular recovery and air drying of A. tumefaciens:P. brasiliensis mixtures are essential for ATMT. Overall, our data indicate a transformation efficiency of 78+/-9 transformants/co-cultivation (5+/-1 transformants/10(6) target cells). P. brasiliensis GFP-expressing isolates were also constructed by insertion of the GFP gene under the control of several fungal promoters. RT-PCR, epifluorescence microscopy and flow cytometry analysis revealed Gfp visualization for all studied promoters but without significant differences in fluorescence and gene expression levels. Moreover, we present evidence for the occurrence of random single gene copy integration per haploid nuclei and the generation of homokaryon progeny, relevant for the future use in targeted mutagenesis and linking mutations to phenotypes. 相似文献
15.
Calich VL da Costa TA Felonato M Arruda C Bernardino S Loures FV Ribeiro LR de Cássia Valente-Ferreira R Pina A 《Mycopathologia》2008,165(4-5):223-236
Innate immunity is based in pre-existing elements of the immune system that directly interact with all types of microbes leading
to their destruction or growth inhibition. Several elements of this early defense mechanism act in concert to control initial
pathogen growth and have profound effect on the adaptative immune response that further develops. Although most studies in
paracoccidioidomycosis have been dedicated to understand cellular and humoral immune responses, innate immunity remains poorly
defined. Hence, the main purpose of this review is to present and discuss some mechanisms of innate immunity developed by
resistant and susceptible mice to Paracoccidioides brasiliensis infection, trying to understand how this initial host-pathogen interface interferes with the protective or deleterious adaptative
immune response that will dictate disease outcome. An analysis of some mechanisms and mediators of innate immunity such as
the activation of complement proteins, the microbicidal activity of natural killer cells and phagocytes, the production of
inflammatory eicosanoids, cytokines, and chemokines among others, is presented trying to show the important role played by
innate immunity in the host response to P. brasiliensis infection. 相似文献
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17.
Mendes-Giannini MJ Monteiro da Silva JL de Fátima da Silva J Donofrio FC Miranda ET Andreotti PF Soares CP 《Mycopathologia》2008,165(4-5):237-248
Host-fungal interactions are inherently complex and dynamic. In order to identify new microbial targets and develop more effective
anti-fungal therapies, it is important to understand the cellular and molecular mechanisms of disease. Paracoccidioidomycosis
provokes a variety of clinical symptoms, and Paracoccidioides brasiliensis can reach many tissues, but primarily attacks the lungs. The ability of the pathogen to interact with the host surface structures
is essential to further colonization, invasion, and growth. Epithelial cells may represent the first host barrier or the preferential
site of entry of the fungus. For this reason, interactions between P. brasiliensis and Vero/A549 epithelial cells were evaluated, with an emphasis on the adherence, induction of cytoskeletal alterations,
and differential signaling activity of the various surface molecules. The adhesion to and invasion of epithelial cells by
P. brasiliensis may represent strategies employed to thwart the initial host immune response, and may help in the subsequent dissemination
of the pathogen throughout the body. 相似文献
18.
Lucia Maria Carareto Alves Floréncio Figueiredo Sebastião Lázaro Brandão Filho Izaira Tincani Célio L. Silva 《Mycopathologia》1987,99(1):3-7
The influx of inflammatory cells towards the peritoneal cavity in rats inoculated intraperitoneally with subcellular preparations of the fungus Paracoccidioides brasiliensis was studied. In addition to the dead fungus, also fractions F1 of the cell wall, which mainly consisted of polysaccharides and the lipid extract, induced intense cell migration 4 hr after inoculation, with a greatly increased number of polymorphonuclear leucocytes (PMN). Study of the kinetics of cell influx showed that both fraction F1 and the lipid extract initially induced intense PMN migration between the 4th and 24th hr after inoculation of these agents, followed by migration of mononuclear cells (MN) around the 48th hr. We also observed that migration of these cells increased gradually after inoculation of growing doses of fraction F1. The present data suggest that polysaccharides and lipids isolated from P. brasiliensis may participate in the initial phase of the inflammatory response in paracoccidioidomycosis. 相似文献
19.
Ferreira ME Marques Edos R Malavazi I Torres I Restrepo A Nunes LR de Oliveira RC Goldman MH Goldman GH 《Molecular genetics and genomics : MGG》2006,276(5):450-463
The dimorphic pathogenic fungus Paracoccidioides brasiliensis can grow as a prototroph for organic sulfur as a mycelial (non-pathogenic) form, but it is unable to assimilate inorganic sulfur as a yeast (pathogenic) form. Temperature and the inability to assimilate inorganic sulfur are the single conditions known to affect P. brasiliensis mycelium-to-yeast (M-Y) dimorphic transition. For a comprehensive evaluation of genes that have their expression modulated during the M-Y transition in different culture media, we performed a large-scale analysis of gene expression using a microarray hybridization approach. The results of the present work demonstrate the use of microarray hybridization analysis to examine gene expression during the M-Y transition in minimal medium and compare these results with the M-Y transition in complete medium. Our results showed that about 95% of the genes in our microarray are mainly responding to the temperature trigger, independently of the media where the M-Y transition took place. As a preliminary step to understand the inorganic sulfur inability in P. brasiliensis yeast form, we decided to characterize the mRNA accumulation of several genes involved in different aspects of both organic and inorganic sulfur assimilation. Our results suggest that although P. brasiliensis cannot use inorganic sulfur as a single sulfur source to initiate both M-Y transition and Y growth, the fungus can somehow use both organic and inorganic pathways during these growth processes. 相似文献
20.
A relationship between the estrous cycle and non-specific host resistance to Paracoccidioides brasiliensis yeast cells was examined by using both sexes of adult BALB/c mice. They were divided into 6 groups, including a male group and females at proestrus, estrus, metestrus-I, metestrus-II and diestrus. The mice received yeast cells through three different inoculation routes; intravenous, intraperitoneal and intratracheal. In all of the inoculation routes, the clearance of the yeast cells was influenced by the estrous cycle. The female mice at estrus, which might have high blood estrogen levels, showed a marked clearance of the yeast cells from the blood, peritoneal cavity and lungs. These results suggested that non-specific host resistance to the yeast cells was enhanced by estrogen. All female groups inoculated by the three routes showed higher clearance of the yeast cells than the male group. 相似文献