Photodynamic therapy reduces viability, enhances itraconazole activity, and impairs mitochondrial physiology of Sporothrix brasiliensis.

Sporothrix brasiliensis is the main agent of sporotrichosis in Brazil, with few therapeutic options. This study aimed to investigate the in vitro efficacy of photodynamic therapy using a diode laser (InGaAIP) in combination with the photosensitizer methylene blue against S. brasiliensis yeasts.

Toll-like receptor 4 (TLR4) is the major pattern recognition receptor triggering the protective effect of a extracellular vesicle-based vaccine prototype in murine systemic candidiasis.

Systemic candidiasis remains a significant public health concern worldwide, with high mortality rates despite available antifungal drugs. Drug-resistant strains add to the urgency for alternative therapies. In this context, vaccination has reemerged as a prominent immune-based strategy.

Electron Microscopy of Cryptococcus neoformans: Processing Challenges to Avoid Artifacts.

This chapter describes methodological details for preparing specimens of Cryptococcus neoformans (although it can be applied to any species of the genus) and their subsequent analysis by scanning and transmission electron microscopy. Adaptations to conventional protocols for better preservation of the sample, as well as to avoid artifacts, are presented. The protocols may be used to examine both the surface ultrastructure and the interior of this pathogenic fungus in detail.

Comparative Analysis of Capsular and Secreted Polysaccharides Produced by and .

Fungal infections are a global public health challenge, especially among immunocompromised patients. yeasts, such as , have emerged as opportunistic pathogens, but have received less attention than . This study aimed to characterize the polysaccharides of and compare them with those of , analyzing their clinical implications.

Metabolic Plasticity and Virulence-Associated Factors of Strains Related to Familiar Outbreaks of Cat-to-Human Transmitted Sporotrichosis.

is the main agent of zoonotic sporotrichosis transmitted by domestic cats in South America. In humans, sporotrichosis commonly presents with cutaneous or lymphocutaneous lesions, and in cats, with multiple ulcerated skin lesions associated with enlarged lymph nodes and respiratory signs. Fungal virulence factors may affect the clinical presentation of the mycoses.

Metabolic and morphostructural plasticity of environmental and animal strains of Nannizzia gypsea.

Nannizzia gypsea is a geophylic agent of human and animal dermatophytosis. This study compares the metabolic and morphostructural plasticity of N. gypsea strains isolated from moss, sand, and a dog.

Phospholipase B Is Critical for Cryptococcus neoformans Survival in the Central Nervous System.

Cryptococcus neoformans () is an opportunistic, encapsulated, yeast-like fungus that causes severe meningoencephalitis, especially in countries with high HIV prevalence. In addition to its well-known polysaccharide capsule, has other virulence factors such as phospholipases, a heterogeneous group of enzymes that hydrolyze ester linkages in glycerophospholipids. Phospholipase B (PLB1) has been demonstrated to play a key role in pathogenicity.

Clinical Challenges of Emerging and Re-Emerging Yeast Infections in the Context of the COVID-19 Pandemic.

During the geological eras, some fungi, through adaptation and/or environmental/ecological pressure, interacted directly and indirectly with humans, through occasionally harmful interaction interdependent on the individual's immunological condition. Infections caused by yeasts are underreported, subjugated, and underdiagnosed, and treatment is restricted to a few drugs, even after the significant progress of medicine and pharmacology. In the last centuries, antagonistically, there has been an exponential increase of immunocompromised individuals due to the use of immunosuppressive drugs such as corticosteroids, increased cases of transplants, chemotherapeutics, autoimmune diseases, neoplasms, and, more recently, coronavirus disease 2019 (COVID-19).

Vaccination with Live or Heat-Killed Aspergillus fumigatus Δ Conidia Fully Protects Immunocompromised Mice from Invasive Aspergillosis.

Aspergillus fumigatus causes invasive aspergillosis (IA) in immunocompromised patients, resulting in high mortality rates. Currently, no vaccine formulations to promote immune protection in at-risk individuals have been developed. In this work, we deleted the sterylglucosidase-encoding gene, , in Aspergillus fumigatus and investigated its role in fungal virulence and host vaccine protection.

Comparative Biophysical and Ultrastructural Analysis of Melanins Produced by Clinical Strains of Different Species From the Trichosporonaceae Family.

Melanin is one of the most studied virulence factors in pathogenic fungi. This pigment protects them from a series of both environmental and host stressors. Among basidiomycetes, and are known to produce melanin in the presence of phenolic precursors.

Candida spp. co-infection in COVID-19 patients with severe pneumonia: Prevalence study and associated risk factors.

Background: Invasive fungal infections (IFI) are increasing in prevalence in recent years. In the last few months, the rise of COVID-19 patients has generated a new escalation in patients presenting opportunistic mycoses, mainly by Aspergillus. Candida infections are not being reported yet.

produces a melanin-like pigment that protects against stress conditions encountered during parasitism.

Melanin has been linked to pathogenesis in several fungi. They often produce melanin-like pigments in the presence of L-dihydroxyphenylalanine (L-DOPA), but this is poorly studied in . was grown in minimal medium with or without L-DOPA supplementation and submitted to a chemical treatment with denaturant and hot acid.

Ultrastructural Study of Surface During Budding Events.

is a fungal pathogen that causes life-threatening infections in immunocompromised individuals. It is surrounded by three concentric structures that separate the cell from the extracellular space: the plasma membrane, the cell wall and the polysaccharide (PS) capsule. Although several studies have revealed the chemical composition of these structures, little is known about their ultrastructural organization and remodeling during budding events.

Glycans From Distinct Genotypes Share Structural and Serological Similarities to Glucuronoxylomannan.

The cell wall is a ubiquitous structure in the fungal kingdom, with some features varying depending on the species. Additional external structures can be present, such as the capsule of (), its major virulence factor, mainly composed of glucuronoxylomannan (GXM), with anti-phagocytic and anti-inflammatory properties. The literature shows that other cryptococcal species and even more evolutionarily distant species, such as the , and can produce GXM-like polysaccharides displaying serological reactivity to GXM-specific monoclonal antibodies (mAbs), and these complex polysaccharides have similar composition and anti-phagocytic properties to cryptococcal GXM.

Dexamethasone and Methylprednisolone Promote Cell Proliferation, Capsule Enlargement, and Dissemination of .

is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, who often have some inflammatory condition and, therefore, end up using glucocorticoids, such as dexamethasone and methylprednisolone. Although the effects of this class of molecules during cryptococcosis have been investigated, their consequences for the biology of is less explored. Here, we studied the effects of dexamethasone and methylprednisolone on the metabolism and on the induction of virulence factors in .

Systemic mycoses: a potential alert for complications in COVID-19 patients.

As the global COVID-19 pandemic spreads worldwide, new challenges arise in the clinical landscape. The need for reliable diagnostic methods, treatments and vaccines for COVID-19 is the major worldwide urgency. While these goals are especially important, the growing risk of co-infections is a major threat not only to the health systems but also to patients' lives.

Hypervirulence and cross-resistance to a clinical antifungal are induced by an environmental fungicide in Cryptococcus gattii.

The increasing human population requires ongoing efforts in food production. This is frequently associated with an increased use of agrochemicals, leading to environmental contamination and altering microbial communities, including human fungal pathogens that reside in the environment. Cryptococcus gattii is an environmental yeast and is one of the etiological agents of cryptococcosis.

The mechanical properties of microbial surfaces and biofilms.

Microbes can modify their surface structure as an adaptive mechanism for survival and dissemination in the environment or inside the host. Altering their ability to respond to mechanical stimuli is part of this adaptive process. Since the 1990s, powerful micromanipulation tools have been developed that allow mechanical studies of microbial cell surfaces, exploring little known aspects of their dynamic behavior.

Effect of cell geometry in the evaluation of erythrocyte viscoelastic properties.

The red blood cell membrane-cytoskeleton is a complex structure mainly responsible for giving the cell rigidity and shape. It also provides the erythrocyte with the ability to pass through narrow capillaries of the vertebrate blood circulatory system. Although the red blood cell viscoelastic properties have been extensively studied, reported experimental data differ by up to three orders of magnitude.

Membrane Elastic Properties During Neural Precursor Cell Differentiation.

Neural precursor cells differentiate into several cell types that display distinct functions. However, little is known about how cell surface mechanics vary during the differentiation process. Here, by precisely measuring membrane tension and bending modulus, we map their variations and correlate them with changes in neural precursor cell morphology along their distinct differentiation fates.

Rheological properties of cryptococcal polysaccharide change with fiber size, antibody binding and temperature.

is the major agent of cryptococcosis. The main virulence factor is the polysaccharide (PS) capsule. Changes in cryptococcal PS properties have been poorly elucidated.

Interaction with Pantoea agglomerans Modulates Growth and Melanization of Sporothrix brasiliensis and Sporothrix schenckii.

Sporothrix brasiliensis and Sporothrix schenckii stand as the most virulent agents of sporotrichosis, a worldwide-distributed subcutaneous mycosis. The origin of Sporothrix virulence seems to be associated with fungal interactions with organisms living in the same environment. To assess this hypothesis, the growth of these two species in association with Pantoea agglomerans, a bacterium with a habitat similar to Sporothrix spp.

Glucuronoxylomannan and Sterylglucoside Are Required for Host Protection in an Animal Vaccination Model.

is an encapsulated fungal pathogen that causes meningoencephalitis. There are no prophylactic tools for cryptococcosis. Previously, our group showed that a mutant lacking the gene encoding sterylglucosidase (Δ) induced protection in both immunocompetent and immunocompromised murine models of cryptococcosis.

The hidden pathogenic potential of environmental fungi.

Invasive fungal infections are a growing threat to immunocompromised patients, highlighting the importance of monitoring fungal pathogens. Global warming (including climatic oscillations) may select for environmental species that have acquired thermotolerance, a key step toward pathogenesis to humans. Also, important virulence factors have developed in environmental fungi, because they are essential for yeast survival in the environment.