Melanin in the dimorphic fungal pathogen Paracoccidioides brasiliensis: effects on phagocytosis, intracellular resistance and drug susceptibility

Wild animals infected with Paracoccidioides brasiliensis represent important indicators of this fungal agent presence in the environment. The detection of this pathogen in road-killed wild animals has shown to be a key strategy for eco-epidemiological surveillance of paracoccidioidomycosis (PCM), helping to map hot spots for human infection. Molecular detection of P. brasiliensis in wild animals from PCM outbreak areas has not been performed so far. The authors investigated the presence of P. brasiliensis through nested-PCR in tissue samples obtained from road-killed animals collected nearby a human PCM outbreak spot, Rio de Janeiro state, Brazil and border areas. Eighteen species of mammals were analyzed: Dasypus novemcinctus (nine-banded armadillo, n = 6), Cerdocyon thous (crab-eating fox, n = 4), Coendou spinosus (hairy dwarf porcupine, n = 2), Lontra longicaudis (Neotropical river otter, n = 1), Procyon cancrivorus (crab-eating raccoon, n = 1), Galactis cuja (lesser grison, n = 1), Tamandua tetradactyla (collared anteater, n = 1), Cuniculus paca (paca, n = 1), and Bradypus variegatus (brown-throated three-toed sloth, n = 1). Specific P. brasiliensis sequences were detected in the liver, spleen, and lymph node samples from 4/6 (66.7%) D. novemcinctus, reinforcing the importance of these animals on Paracoccidioides ecology. Moreover, lymph nodes samples from two C. thous, as well as lung samples from the C. paca were also positive. A literature review of Paracoccidioides spp. in vertebrates in Brazil indicates C. thous and C. paca as new hosts for the fungal pathogen P. brasiliensis.

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Detection of Melanin-Like Pigments in the Dimorphic Fungal Pathogen Paracoccidioides brasiliensis In Vitro and during Infection

Infection and Immunity ◽

10.1128/iai.69.9.5760-5767.2001 ◽

2001 ◽

Vol 69 (9) ◽

pp. 5760-5767 ◽

Cited By ~ 86

Author(s):

Beatriz L. Gómez ◽

Joshua D. Nosanchuk ◽

Soraya Dı́ez ◽

Sirida Youngchim ◽

Philip Aisen ◽

...

Keyword(s):

Fungal Pathogen ◽

Proteolytic Enzymes ◽

Paracoccidioides Brasiliensis ◽

Polyacrylamide Gel Electrophoresis ◽

Yeast Cells ◽

Resonance Spectroscopy ◽

Microbial Infections ◽

Melanin Binding

ABSTRACT Melanins are implicated in the pathogenesis of several human diseases, including some microbial infections. In this study, we analyzed whether the conidia and the yeasts of the thermally dimorphic fungal pathogen Paracoccidioides brasiliensis produce melanin or melanin-like compounds in vitro and during infection. Growth of P. brasiliensis mycelia on water agar alone produced pigmented conidia, and growth of yeasts in minimal medium withl-3,4-dihydroxyphenylalanine (l-DOPA) produced pigmented cells. Digestion of the pigmented conidia and yeasts with proteolytic enzymes, denaturant, and hot concentrated acid yielded dark particles that were the same size and shape as their propagules. Immunofluorescence analysis demonstrated reactivity of a melanin-binding monoclonal antibody (MAb) with the pigmented conidia, yeasts, and particles. Electron spin resonance spectroscopy identified the yeast-derived particles produced in vitro when P. brasiliensis was grown in l-DOPA medium as a melanin-like compound. Nonreducing polyacrylamide gel electrophoresis of cytoplasmic yeast extract revealed a protein that catalyzed melanin synthesis from l-DOPA. The melanin binding MAb reacted with yeast cells in tissue from mice infected with P. brasiliensis. Finally digestion of infected tissue liberated particles reactive to the melanin binding MAb that had the typical morphology of P. brasiliensis yeasts. These data strongly suggest that P. brasiliensis propagules, both conidia and yeast cells, can produce melanin or melanin-like compounds in vitro and in vivo. Based on what is known about the function of melanin in the virulence of other fungi, this pigment may play a role in the pathogenesis of paracoccidioidomycosis.

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Genes Potentially Relevant in the Parasitic Phase of the Fungal Pathogen Paracoccidioides brasiliensis

Mycopathologia ◽

10.1007/s11046-010-9349-7 ◽

2010 ◽

Vol 171 (1) ◽

pp. 1-9 ◽

Cited By ~ 11

Author(s):

Clayton Luiz Borges ◽

Alexandre Melo Bailão ◽

Sonia N. Báo ◽

Maristela Pereira ◽

Juliana Alves Parente ◽

...

Keyword(s):

Fungal Pathogen ◽

Paracoccidioides Brasiliensis ◽

Parasitic Phase

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A novel Hsp90 phospho-switch modulates virulence in the major human fungal pathogen Candida albicans

10.1101/2020.09.23.309831 ◽

2020 ◽

Author(s):

Leenah Alaalm ◽

Julia L. Crunden ◽

Mark Butcher ◽

Ulrike Obst ◽

Ryann Whealy ◽

...

Keyword(s):

Candida Albicans ◽

Stress Responses ◽

Fungal Pathogen ◽

Drug Targets ◽

Fungal Infections ◽

Pathogenic Fungi ◽

First Record ◽

Drug Susceptibility ◽

Phosphorylation Sites ◽

Fungal Virulence

The ubiquitous molecular chaperone Hsp90 is a key regulator of cellular proteostasis and environmental stress responses. Hsp90 also regulates cellular morphogenesis, drug resistance, and virulence in human pathogenic fungi, which kill more than 1.6 million patients each year worldwide. Invasive fungal infections are difficult to treat due to the lack of effective antifungal therapies, resulting in mortality rates of up to 95%. As a key regulator of fungal virulence, Hsp90 is an attractive therapeutic target. However, fungal and animal homologs are highly conserved, impeding fungal-specific targeting. Thus, understanding the factors that regulate Hsp90 could provide an alternative strategy aimed at exclusively targeting this regulator of fungal virulence. Here, we demonstrate how CK2-mediated phosphorylation of two Hsp90 residues modulates virulence in a major fungal pathogen of humans, Candida albicans. We combined proteomics, molecular evolution and structural modelling with molecular biology to identify and characterize two Hsp90 phosphorylation sites. Phosphorylation negatively affects thermal stress response, morphogenesis, drug susceptibility and fungal virulence. Our results provide the first record of specific Hsp90 phosphorylation sites acting as modulators of fungal virulence. Post-translational modifications of Hsp90 could prove valuable in future exploitation as antifungal drug targets.

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Use of Morphology Index Histograms to Quantify Populations of the Fungal Pathogen Paracoccidioides Brasiliensis

Microbiology ◽

10.1099/00221287-143-1-197 ◽

1997 ◽

Vol 143 (1) ◽

pp. 197-202 ◽

Cited By ~ 5

Author(s):

G. San-Blas ◽

R. Padron ◽

L. Alamo ◽

F. San-Blas

Keyword(s):

Fungal Pathogen ◽

Paracoccidioides Brasiliensis

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Characterization of a secreted aspartyl protease of the fungal pathogen Paracoccidioides brasiliensis

Medical Mycology ◽

10.1080/13693780802695512 ◽

2009 ◽

pp. 1-11

Author(s):

Bruno Aluisio Coutinho De Assis Tacco ◽

Juliana Alves Parente ◽

Monica Santiago Barbosa ◽

Sonia Nair Bao ◽

Tercio De Souza Goes ◽

...

Keyword(s):

Fungal Pathogen ◽

Paracoccidioides Brasiliensis ◽

Aspartyl Protease

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Studies on the Fungal Pathogen of Dutch Elm Disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098502 ◽

1981 ◽

Vol 39 ◽

pp. 400-401

Author(s):

H.M. Mazzone ◽

G. Wray ◽

R. Zerillo

Keyword(s):

Fungal Pathogen ◽

Fungal Growth ◽

Polymyxin B ◽

The United States ◽

Dutch Elm Disease ◽

Effective Control ◽

Sabouraud Agar ◽

Total Inhibition ◽

Zones Of Inhibition ◽

Control Plate

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.

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