Cryptococcus neoformans
 var.
 grubii
 : Separate Varietal Status for
 Cryptococcus neoformans
 Serotype A Isolates

Franzot, Sarah P.; Salkin, Ira F.; Casadevall, Arturo

doi:10.1128/jcm.37.3.838-840.1999

Cited by 377 publications

(132 citation statements)

References 32 publications

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“…To quote Hudson andCoyne (2002, p. 1557), a species recognized by GSC is a ''basal, exclusive group of organisms, whose members are all more closely related to each other than they are to any organisms outside the group, and that contains no exclusive group within it.'' In all cases in which the PSC has been used to describe species of global isolates of a morphological fungal species, cryptic species have been recognized, for example within Schizophyllum commune (James et al 1999), Sclerotinia sclerotiorum (Carbone and Kohn 2001a) and outbreeding Neurospora species (Dettman et al 2003b) (and see also Demanche et al 2001;Fisher et al 2002;Franzot et al 1999;Kasuga et al 2003;Koufopanou et al 1997;Sullivan et al 1995;Xu et al 2000). BSR and PSR have been compared for species of Neurospora and the biological species recognized by success in mating tests are nearly the same as the phylogenetic species described by the concordance of multiple gene genealogies (Dettman et al 2003a); the two species concepts are effectively congruent.…”

Section: Species Recognitionmentioning

confidence: 99%

Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

Pringle

Baker

Platt

et al. 2005

Evol

122

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Microbes and other organisms smaller than one to a few millimeters in size are hypothesized to have global populations, in contrast to the geographically restricted ranges of larger organisms. However, fungi, which routinely have reproductive propagules no larger than 10 micrometers, challenge the generality of this hypothesis because recent studies have shown that globally distributed morphological species embrace two or more geographically restricted phylogenetic species. We used the concordance of gene genealogies to recognize phylogenetic species in the globally distributed opportunistic human pathogenic fungus, Aspergillus fumigatus. Based on DNA sequence data of five loci for each of 63 individuals collected from five continents, we have delineated two phylogenetic species in this single morphological species. Unlike all other fungi examined to date, both genetically isolated groups showed a global distribution with no evidence of a correlation between genotype and geographic location. Sexual reproduction has never been observed in A. fumigatus, but when the same data were used to explore the association of alleles at the five loci for one of the phylogenetic species, evidence was found to support recombination. The discovery of a cryptic species is medically relevant because different species are likely to differ in virulence or drug resistance. The discovery of a globally distributed A. fumigatus species clade highlights the need for ecological studies of the fungus to either document global dispersal or propose alternative mechanisms by which it persists as single, global phylogenetic population.

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Section: Species Recognitionmentioning

confidence: 99%

Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

Pringle

Baker

Platt

et al. 2005

Evol

122

View full text Add to dashboard Cite

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“…Three subspecies of C. neoformans have been recognized, i.e., var. grubii (serotype A) [5], var. gattii (serotype B and C) and var.…”

Section: Introductionmentioning

confidence: 99%

Role of laccase in the biology and virulence of

Zhu

Williamson

2004

FEMS Yeast Research

219

180

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Laccase is an important virulence factor for the human pathogen, Cryptococcus neoformans. In this review, we examine the structural, biological and genetic features of the enzyme and its role in the pathogenesis of cryptococcosis. Laccase is expressed in C. neoformans as a cell wall enzyme that possesses a broad spectrum of activity oxidizing both polyphenolic compounds and iron. Two paralogs, CNLAC1 and CNLAC2, are present in the fungus, of which the first one expresses the dominant enzyme activity under glucose starvation conditions. Regulation of the enzyme is in response to various environmental signals including nutrient starvation, the presence of multivalent cations and temperature stress, and is mediated through multiple signal transduction pathways. Study of the function and regulation of this important virulence factor has led to further understanding of mechanisms of fungal pathogenesis and the regulation of stress response in the host cell environment.

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“…neoformans (serotype D) and C. neoformans var. grubii (serotype A), as well as a hybrid between serotypes A and D. The closely related Cryptococcus gattii (serotypes B and C) was formerly considered a variety of C. neoformans (Franzot et al, 1999). Cryptococcosis is thought to result primarily from inhalation of infectious propagules (probably basidiospores) (Rodrigues et al, 1999) with initial localization in the respiratory tract and then dissemination to other tissues, particularly brain (Rodrigues et al, 1999;Shoham and Levitz, 2005;Caswell and Williams, 2007;Lopez, 2007).…”

mentioning

confidence: 99%

Spinal Cryptococcoma in an Immunocompetent Cat

Belluco

Thibaud

Guillot

et al. 2008

Journal of Comparative Pathology

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This report describes an unusual case of primary cryptococcoma in the proximal thoracic spinal cord of an 11-year-old immunocompetent cat from a farm on which there were large numbers of pigeons. This animal was referred for examination with progressive paralysis and shown to be free from feline immunodeficiency virus, feline leukaemia virus, feline coronavirus and Toxoplasma gondii. It died 2 months later. At necropsy, the only lesion detected was a malacic area, 4cm in length, in the spinal cord. Histopathological examination of the spinal cord revealed severe granulomatous inflammation associated with large numbers of encapsulated yeast cells. In addition to the granulomatous host response, necrosis, digestion chambers, Gitter cells, spheroids and lymphocytic perivascular cuffs were features of the malacic areas. Immunohistochemistry confirmed the presence of Cryptococcus neoformans var. grubii yeast cells.

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Cryptococcus neoformans var. grubii : Separate Varietal Status for Cryptococcus neoformans Serotype A Isolates

Cited by 377 publications

References 32 publications

Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

Role of laccase in the biology and virulence of

Spinal Cryptococcoma in an Immunocompetent Cat

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