Polysaccharide diversity in VNI isolates of Cryptococcus neoformans from Roraima, Northern Brazil

Publication date: Available online 12 June 2019Source: Fungal BiologyAuthor(s): Halan D. Dal Pupo, Bianca A.G. Sena, Flavia C.G. Reis, Lumena Machado, Silvana T. Fortes, João N. de Almeida Junior, Rodrigo M.C. Godinho, Marcio L. RodriguesAbstractSpecies of the Cryptococcus genus comprise environmental, encapsulated fungal pathogens that cause lethal meningitis in immunosuppressed individuals. In humans, fungal uptake of hypocapsular Cryptococcus by macrophages was associated with high fungal burden in the cerebrospinal fluid and long-term patient survival. On the basis of the key role of the cryptococcal capsule in disease, we analyzed the diversity of capsular structures in 23 isolates from pigeon excreta collected in the cities of Boa Vista, Bonfim and Pacaraima, in the state of Roraima (Northern Brazil). All isolates were identified as C. neoformans (VNI genotype) by MALDI-TOF mass spectrometry. Through a combination of fluorescence microscopy, flow cytometry, ELISA and spectrophotometric methods, each isolate was characterized at the phenotypical level, which included measurements of growth rates at 30 and 37oC, pigmentation, cell body size, capsular dimensions, serological reactivity, urease production and ability to produce extracellular glucuronoxylomannan (GXM), the main capsular components of C. neoformans. With the exception of melanization, a formidable diversity was observed considering all parameters tested in our study. Of note, hyper and hypo producers of GXM ...
Source: Fungal Biology - Category: Biology Source Type: research