Role of melanin in the pathogenesis of cutaneous sporotrichosis

Madrid, Isabel Martins; Xavier, Melissa Orzechowski; Mattei, Antonella Souza; Fernandes, Cristina Gevehr; Guim, Thomaz N.; Santin, Rosema; Schuch, Luiz Filipe Damé; Nobre, Márcia de Oliveira; Meireles, Mário Carlos Araújo

doi:10.1016/j.micinf.2009.10.004

Cited by 38 publications

(23 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This character is shared by only five other Sporothrix species, also found in soil (Table 2). The pigmented blastoconidia appear to be an adaptation to survive in the soil, and melanin most probably allows these opportunistic pathogens to overcome human and animal immune systems when implanted through trauma in skin or muscle tissue (Romero-Martinez et al., 2000, Morris-Jones et al., 2003, Madrid et al., 2010b, Teixeira et al., 2010, Teixeira et al., 2015). Most other species in the Ophiostomatales apparently lack this ability, and despite the fact that they are commonly present on freshly cut wood in virtually every sawmill, pulp mill and plantation globally, they very rarely cause disease.…”

Section: Discussionmentioning

confidence: 99%

The divorce of Sporothrix and Ophiostoma: solution to a problematic relationship

Beer

Duong

Wingfield

2016

Studies in Mycology

154

127

View full text Add to dashboard Cite

One of the causal agents of human sporotrichosis, Sporothrix schenckii, is the type species of the genus Sporothrix. During the course of the last century the asexual morphs of many Ophiostoma spp. have also been treated in Sporothrix. More recently several DNA-based studies have suggested that species of Sporothrix and Ophiostoma converge in what has become known as Ophiostoma s. lat. Were the one fungus one name principles adopted in the Melbourne Code to be applied to Ophiostoma s. lat., Sporothrix would have priority over Ophiostoma, resulting in more than 100 new combinations. The consequence would be name changes for several economically important tree pathogens including O. novo-ulmi. Alternatively, Ophiostoma could be conserved against Sporothrix, but this would necessitate changing the names of the important human pathogens in the group. In this study, we sought to resolve the phylogenetic relationship between Ophiostoma and Sporothrix. DNA sequences were determined for the ribosomal large subunit and internal transcribed spacer regions, as well as the beta-tubulin and calmodulin genes in 65 isolates. The results revealed Sporothrix as a well-supported monophyletic lineage including 51 taxa, distinct from Ophiostoma s. str. To facilitate future studies exploring species level resolution within Sporothrix, we defined six species complexes in the genus. These include the Pathogenic Clade containing the four human pathogens, together with the S. pallida-, S. candida-, S. inflata-, S. gossypina- and S. stenoceras complexes, which include environmental species mostly from soil, hardwoods and Protea infructescences. The description of Sporothrix is emended to include sexual morphs, and 26 new combinations. Two new names are also provided for species previously treated as Ophiostoma.

show abstract

Section: Discussionmentioning

confidence: 99%

The divorce of Sporothrix and Ophiostoma: solution to a problematic relationship

Beer

Duong

Wingfield

2016

Studies in Mycology

154

127

View full text Add to dashboard Cite

show abstract

“…In addition, infection increases the expression of melanin synthesis genes in this fungus (Bailao et al 2006). Lastly, in a sporotrichosis model, melanized fungi show greater dissemination in a mouse footpad model compared to mutants unable to make melanin (Madrid et al 2010). …”

Section: Introductionmentioning

confidence: 99%

Synthesis and assembly of fungal melanin

Eisenman

Casadevall

2011

Appl Microbiol Biotechnol

551

415

View full text Add to dashboard Cite

Melanin is a unique pigment with myriad functions that is found in all biological kingdoms. It is multifunctional, providing defense against environmental stresses such as ultraviolet (UV) light, oxidizing agents and ionizing radiation. Melanin contributes to the ability of fungi to survive in harsh environments. In addition, it plays a role in fungal pathogenesis. Melanin is an amorphous polymer that is produced by one of two synthetic pathways. Fungi may synthesize melanin from endogenous substrate via a 1,8-dihydroxynaphthalene (DHN) intermediate. Alternatively, some fungi produce melanin from l-3,4-dihydroxyphenylalanine (l-dopa). The detailed chemical structure of melanin is not known. However, microscopic studies show that it has an overall granular structure. In fungi, melanin granules are localized to the cell wall where they are likely cross-linked to polysaccharides. Recent studies suggest the fungal melanin may be synthesized in internal vesicles akin to mammalian melanosomes and transported to the cell wall. Potential applications of melanin take advantage of melanin's radioprotective properties and propensity to bind to a variety of substances.

show abstract

“…However, other relevant factors for the pathogenesis of these organisms need to be elucidated, as the mechanisms involving the colonization and rapid aggravation of the disease are still not clearly understood. Other virulence factors already known in S. schenckii are extracellular enzymes [20-22], adhesins [23,24] and melanin [25,26]. The major adhesin described on the cell surface of S. schenckii , gp70, has been shown to mediate the binding of yeast cells to the dermal matrix and to fibronectin [24,27].…”

Section: Introductionmentioning

confidence: 99%

Differences in Cell Morphometry, Cell Wall Topography and Gp70 Expression Correlate with the Virulence of Sporothrix brasiliensis Clinical Isolates

et al. 2013

View full text Add to dashboard Cite

Sporotrichosis is a chronic infectious disease affecting both humans and animals. For many years, this subcutaneous mycosis had been attributed to a single etiological agent; however, it is now known that this taxon consists of a complex of at least four pathogenic species, including Sporothrix schenckii and Sporothrix brasiliensis. Gp70 was previously shown to be an important antigen and adhesin expressed on the fungal cell surface and may have a key role in immunomodulation and host response. The aim of this work was to study the virulence, morphometry, cell surface topology and gp70 expression of clinical isolates of S. brasiliensis compared with two reference strains of S. schenckii. Several clinical isolates related to severe human cases or associated with the Brazilian zoonotic outbreak of sporotrichosis were genotyped and clustered as S. brasiliensis. Interestingly, in a murine subcutaneous model of sporotrichosis, these isolates showed a higher virulence profile compared with S. schenckii. A single S. brasiliensis isolate from an HIV-positive patient not only showed lower virulence but also presented differences in cell morphometry, cell wall topography and abundant gp70 expression compared with the virulent isolates. In contrast, the highly virulent S. brasiliensis isolates showed reduced levels of cell wall gp70. These observations were confirmed by the topographical location of the gp70 antigen using immunoelectromicroscopy in both species. In addition, the gp70 molecule was sequenced and identified using mass spectrometry, and the sequenced peptides were aligned into predicted proteins using Blastp with the S. schenckii and S. brasiliensis genomes.

show abstract

Role of melanin in the pathogenesis of cutaneous sporotrichosis

Cited by 38 publications

References 19 publications

The divorce of Sporothrix and Ophiostoma: solution to a problematic relationship

The divorce of Sporothrix and Ophiostoma: solution to a problematic relationship

Synthesis and assembly of fungal melanin

Differences in Cell Morphometry, Cell Wall Topography and Gp70 Expression Correlate with the Virulence of Sporothrix brasiliensis Clinical Isolates

Contact Info

Product

Resources

About