New Insights Into The Melanin Structure Of .

is a filamentous fungus with a global distribution, manifesting particularly higher prevalence in human-impacted environments. This organism is associated with a wide spectrum of human infections, especially in immunosuppressed individuals, for whom it causes severe and debilitating illnesses with high morbidity and mortality that are compounded by its pan-resistant profile with respect to antifungal drugs. Melanin is a ubiquitous pigment among fungi with a broad range of actions that include promoting fungal virulence.

s rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia.

causes lethal meningitis and accounts for approximately 10%-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this fungus invades the mammalian brain. To investigate the dynamics of tissue invasion, we mapped fungal localization and host cell interactions in infected brain, lung, and upper airways using mouse models of systemic and airway infection.

rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia.

The fungus causes lethal meningitis in humans with weakened immune systems and is estimated to account for 10-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this environmental fungus evades the immune system and invades the mammalian brain before the onset of overt symptoms. To investigate the dynamics of C.

Cuticular profiling of insecticide resistant Aedes aegypti.

Insecticides have made great strides in reducing the global burden of vector-borne disease. Nonetheless, serious public health concerns remain because insecticide-resistant vector populations continue to spread globally. To circumvent insecticide resistance, it is essential to understand all contributing mechanisms.

Getaway car: Fungal HscA steers human phagosomal p11 into an escape route.

In this issue of Cell Host & Microbe, Jia and colleagues discover how the human p11 (s100A10)-Anxa2 heterodimer drives sorting of microbial phagosomes into recycling versus degradative pathways. In a remarkable evolutionary arms race, the Aspergillus fumigatus protein HscA latches to p11 to steer its phagosome away from fungal killing.

Scientific civility and academic performance.

In modern science, interdisciplinary and collaborative research is encouraged among scientists to solve complex problems. However, when the time comes to measure an individual's academic productivity, collaborative efforts are hard to conceptualize and quantify. In this study, we hypothesized that a social behavior coined "scientific civility", which encompasses civility, collaboration, cooperation, or a combination of these, enhances an individual's productivity influencing their academic performance.

Cuticular profiling of insecticide resistant .

Insecticides have made great strides in reducing the global burden of vector-borne disease. Nonetheless, serious public health concerns remain because insecticide-resistant vector populations continue to spread globally. To circumvent insecticide resistance, it is essential to understand all contributing mechanisms.

Omics Approaches for Understanding Biogenesis, Composition and Functions of Fungal Extracellular Vesicles.

Extracellular vesicles (EVs) are lipid bilayer structures released by organisms from all kingdoms of life. The diverse biogenesis pathways of EVs result in a wide variety of physical properties and functions across different organisms. Fungal EVs were first described in 2007 and different omics approaches have been fundamental to understand their composition, biogenesis, and function.

Glyphosate inhibits melanization and increases susceptibility to infection in insects.

Melanin, a black-brown pigment found throughout all kingdoms of life, has diverse biological functions including UV protection, thermoregulation, oxidant scavenging, arthropod immunity, and microbial virulence. Given melanin's broad roles in the biosphere, particularly in insect immune defenses, it is important to understand how exposure to ubiquitous environmental contaminants affects melanization. Glyphosate-the most widely used herbicide globally-inhibits melanin production, which could have wide-ranging implications in the health of many organisms, including insects.

Unconventional Constituents and Shared Molecular Architecture of the Melanized Cell Wall of and Spore Wall of .

The fungal cell wall serves as the interface between the cell and the environment. Fungal cell walls are composed largely of polysaccharides, primarily glucans and chitin, though in many fungi stress-resistant cell types elaborate additional cell wall structures. Here, we use solid-state nuclear magnetic resonance spectroscopy to compare the architecture of cell wall fractions isolated from spores and melanized cells.

Solid-state NMR spectroscopy identifies three classes of lipids in melanized cell walls and whole fungal cells.

A primary virulence-associated trait of the opportunistic fungal pathogen is the production of melanin pigments that are deposited into the cell wall and interfere with the host immune response. Previously, our solid-state NMR studies of isolated melanized cell walls (melanin "ghosts") revealed that the pigments are strongly associated with lipids, but their identities, origins, and potential roles were undetermined. Herein, we exploited spectral editing techniques to identify and quantify the lipid molecules associated with pigments in melanin ghosts.

Geographical distribution and ecological niche modeling of the etiological agents of human sporotrichosis in Venezuela.

The geographical distribution and ecological niche of the two circulating species of the Sporothrix genus in Venezuela was established. For this, 68 isolates of Sporothrix spp. from patients of different regions of the country were analyzed.

Role of the ESCRT Pathway in Laccase Trafficking and Virulence of Cryptococcus neoformans.

The endosomal sorting complex required for transport (ESCRT) plays a crucial role in the transportation and degradation of proteins. We determined that Vps27, a key protein of the ESCRT-0 complex, is required for the transport of the virulence factor laccase to the cell wall in Laccase activity was perturbed, as was melanin production, in Δ strains. In the absence of , there was an accumulation of multivesicular bodies with vacuolar fragmentation and mistargeting of the vacuolar carboxypeptidase CPY/Prc1, resulting in an extracellular localization.

Melanization in Cryptococcus neoformans Requires Complex Regulation.

The fungal human pathogen undergoes melanization in response to nutrient starvation and exposure to exogenous melanin precursors. Melanization protects the fungus against host defense mechanisms such as oxidative damage and other environmental stressors (e.g.

Melanin deposition in two species depends on cell-wall composition and flexibility.

and are two species complexes in the large fungal genus and are responsible for potentially lethal disseminated infections. These two complexes share several phenotypic traits, such as production of the protective compound melanin. In , the pigment associates with key cellular constituents that are essential for melanin deposition within the cell wall.

Intranasal Inoculation of Cryptococcus neoformans in Mice Produces Nasal Infection with Rapid Brain Dissemination.

is an important fungal pathogen, causing life-threatening pneumonia and meningoencephalitis. Brain dissemination of is thought to be a consequence of an active infection in the lung which then extravasates to other sites. Brain invasion results from dissemination via either transport by free yeast cells in the bloodstream or Trojan horse transport within mononuclear phagocytes.

The enigmatic role of fungal annexins: the case of Cryptococcus neoformans.

Annexins are multifunctional proteins that bind to phospholipid membranes in a calcium-dependent manner. Annexins play a myriad of critical and well-characterized roles in mammals, ranging from membrane repair to vesicular secretion. The role of annexins in the kingdoms of bacteria, protozoa and fungi have been largely overlooked.

The structural unit of melanin in the cell wall of the fungal pathogen .

Melanins are synthesized macromolecules that are found in all biological kingdoms. These pigments have a myriad of roles that range from microbial virulence to key components of the innate immune response in invertebrates. Melanins also exhibit unique properties with potential applications in physics and material sciences, ranging from electrical batteries to novel therapeutics.

Cryptococcal Traits Mediating Adherence to Biotic and Abiotic Surfaces.

Several species in the genus are facultative intracellular pathogens capable of causing disease associated with high mortality and morbidity in humans. These fungi interact with other organisms in the soil, and these interactions may contribute to the development of adaptation mechanisms that function in virulence by promoting fungal survival in animal hosts. Fungal adhesion molecules, also known as adhesins, have been classically considered as cell-surface or secreted proteins that play critical roles in microbial pathogenesis or in biofilm formation as structural components.

Cell-wall dyes interfere with Cryptococcus neoformans melanin deposition.

Melanization is an intrinsic characteristic of many fungal species, but details of this process are poorly understood because melanins are notoriously difficult pigments to study. While studying the binding of cell-wall dyes, Eosin Y or Uvitex, to melanized and non-melanized Cryptococcus neoformans cells we noted that melanization leads to reduced fluorescence intensity, suggesting that melanin interfered with dye binding to the cell wall. The growth of C.

Cryptococcus neoformans urease affects the outcome of intracellular pathogenesis by modulating phagolysosomal pH.

Cryptococcus neoformans is a facultative intracellular pathogen and its interaction with macrophages is a key event determining the outcome of infection. Urease is a major virulence factor in C. neoformans but its role during macrophage interaction has not been characterized.

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule.

Spp.: Virulence Factors and Immune-Evasion Strategies.

spp. are dimorphic fungal pathogens responsible for one of the most relevant systemic mycoses in Latin America, paracoccidioidomycosis (PCM). Their exact ecological niche remains unknown; however, they have been isolated from soil samples and armadillos (), which have been proposed as animal reservoir for these fungi.

Molecular epidemiology of human sporotrichosis in Venezuela reveals high frequency of Sporothrix globosa.

Background: Sporotrichosis is a cutaneous and subcutaneous fungal disease of humans and other mammals, known to be caused by the Sporothrix schenckii species complex, which comprises four species of clinical importance: S. brasiliensis, S. globosa, S.