Cryptococcus neoformans

Casadevall, Arturo; Perfect, John R.

doi:10.1128/9781555818241

Cited by 813 publications

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“…grubii, and C. gattii) are the etiological agents of cryptococcosis, an opportunistic systemic mycosis that usually manifests as meningoencephalitis in both humans and animals. Other organs such as lungs and skin can also be infected 4 . Cryptococcal infections are believed to be acquired by inhalation of airborne propagules from environmental source, assumed to be either by desiccated yeast or by basidiospore, deposited in the alveoli of the hosts 12 .…”

Section: Introductionmentioning

confidence: 99%

“…The distribution of serotypes around the world show that clinical and environmental isolates serotype A is present in a widespread distribution 4 , whereas serotypes B and C were mostly limited to tropical and subtropical regions 31 . However, the ecological niche of C. gattii has expanded due to discoveries of the yeast in temperate climate zone 8,13 .…”

Section: Introductionmentioning

confidence: 99%

“…On the contrary, serotype B is the most frequent agent of cryptococcosis in the northeastern region 23,27 . While C. gattii is found to be associated with trees, C. neoformans is mostly recovered from bird excreta 4 .…”

Section: Introductionmentioning

confidence: 99%

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Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil

Ribeiro

Ngamskulrungroj

2008

Rev. Inst. Med. trop. S. Paulo

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SUMMARYCryptococcus neoformans is the major cause of fungal meningitis, a potentially lethal mycosis. Bird excreta can be considered a significant environmental reservoir of this species in urban areas, thirty-three samples of pigeon excreta were collected within the city of Vitoria, Brazil. Cryptococcus neoformans was isolated and identified using standard biochemical assays in ten samples. PCR amplification with primer M13 and orotidine monophosphate pyrophosphorylase (URA5) gene-restriction fragment length polymorphism (RFLP) analysis discerned serotypes and genotypes within this species. All isolates were serotype A (C. neoformans var. grubii) and genotype VNI. The two alternative alleles a and a at the mating type locus were determined by PCR amplification and mating assays performed on V8 medium. All isolates were MAT a mating type but only 50% were able to mate in vitro with the opposite mating type MAT a tester strains (JEC20, KN99a and Bt63). This study adds information on the ecology and molecular characterization of C. neoformans in the Southeast region of Brazil.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil

Ribeiro

Ngamskulrungroj

2008

Rev. Inst. Med. trop. S. Paulo

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“…These serotypes/molecular types differ in their epidemiological, ecological, virulence and molecular characteristics (1,4,(7)(8)(9)(10)(11). Infections are assumed to be acquired via inhalation of infectious propagules, assumed to be desiccated yeast cells (blastoconidia) or basidiospores, from environmental niches (1,7,8).…”

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confidence: 99%

“…The ability of C. neoformans strains to mate is determined by crossing the isolates with appropriate tester strains on nutrient starvation media (1,14,16). The tester strains (usually JEC 20, serotype D, mating type a, and JEC21, serotype D, mating type α) are mixed with the strains to be tested on a special media like V8 agar, SYB (sucrose, biotin, yeast extract) (19).…”

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Determinación in vitro de la pareja sexual en aislamientos del complejo Cryptococcus neoformans

et al. 2007

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Introduction. Within the Cryptococcus neoformans species complex, two species and five serotypes are recognized: C. neoformans (var. grubii, serotype A; var. neoformans, serotype D and a hybrid, serotype AD) and C. gattii (serotypes B and C). Mating types a and α are designated by a single locus, with the mating type α being most prevalent in serotype A and D strains. Objective. To evaluate the ability of Colombian isolates of the C. neoformans species complex to mate in vitro with tester strains of the opposite mating type. Materials and methods. Fifty three clinical isolates were included in this study, 33 C. neoformans var. grubii serotype A, 4 C. neoformans var. neoformans serotype D, all mating type α, and 16 C. gattii, 13 serotype B (mating type a) and 3 serotype C (mating type α ), were mixed on V8 juice agar, using a modified method, with the appropriate tester strains to determine the mating types in vitro. Results. Mating studies revealed that 9 of 33 (27.3%) serotype A isolates and 6 of 13 (46.2%) serotype B isolates were able to mate. Clamp connections and basidia with basidiospores were observed microscopically, indicating that the mating process had occurred. All mating competent serotype A strains were mating type alpha and the serotype B mating competent strains were mating type a. Conclusion. This is the first report of the determination of the mating ability of Colombian Cryptococcus neoformans isolates to mate in vitro with appropriate tester strains, which is of great importance to study the propagation of the fungus around the globe.

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Inositol synthesis and catabolism inCryptococcus neoformans

Molina

Ramos

Douglass

et al. 1999

Yeast

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Cryptococcus neoformans is an opportunistic fungal pathogen that synthesizes and catabolizes inositol. This study demonstrates inositol synthesis from glucose‐6‐phosphate via inositol‐1‐phosphate synthase and catabolism to glucuronic acid via inositol oxygenase in this organism. These inositol synthetic and catabolic pathways are regulated in opposition; repressing conditions for one are inducing conditions for the other. An inositol‐requiring strain was generated by UV mutagenesis. Without inositol, this mutant strain undergoes ‘inositol‐less’ death, during which time the phosphatidylinositol composition of the membranes decreases without alteration of the proportion of other phospholipids. The mutation on this strain results in no detectable inositol synthetic activity but normal (wild‐type) inositol catabolic activity. This inositol‐requiring mutant strain reverted at a high frequency. Classical genetic experiments revealed that the majority of the reverting mutations are at second sites. Interestingly, the revertants exhibited unusual morphological phenotypes when deprived of inositol, while provision of inositol restored wild‐type morphology. Inositol metabolism is clearly important for growth and development of C. neoformans and may be involved in this organism's mechanism for survival as both a saprophyte in soil and a parasite in humans. Copyright © 1999 John Wiley & Sons, Ltd.

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Cryptococcus neoformans

Cited by 813 publications

References 0 publications

Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil

Molecular characterization of environmental Cryptococcus neoformans isolated in Vitoria, ES, Brazil

Determinación in vitro de la pareja sexual en aislamientos del complejo Cryptococcus neoformans

Inositol synthesis and catabolism inCryptococcus neoformans

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