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PubMed1994

The Eiken Latex test for detection of a cryptococcal antigen in cryptococcosis. Comparison with a monoclonal antibody-based latex agglutination test, Pastorex Cryptococcus.

A latex agglutination test for cryptococcal antigen, the Eiken Latex test (Eiken, Tokyo, Japan), was compared with a monoclonal antibody-based agglutination assay, Pastorex Cryptococcus (Diagnostics Pasteur, Marneur-la-Coquette, France). In a murine model of disseminated cryptococcosis, the kinetics of the antigen titers by the Eiken Latex were similar to those by the Pastorex Cryptococcus, but sensitivity was much higher. In HIV-negative patients with pulmonary cryptococcosis, a cryptococcal antigen was detected in 6 of 10 patients by the Eiken Latex test and in only 3 of those patients by the Pastorex Cryptococcus. The results indicate that the Eiken Latex is more sensitive for the detection of the cryptococcal antigen, even in non-disseminated cryptococcosis. The sensitivity and specificity of the Eiken Latex were examined using 195 sera from 25 patients with pulmonary cryptococcosis and 170 patients with non-cryptococcosis. The cutoff value of > or = 1:8 showed a sensitivity of 76% (19/25) and a specificity of 98.9% (168/170).

Agglutination Tests↗

PubMed2006

Polysaccharides and phenolic compounds as substrate for yeasts isolated from rotten wood and description of Cryptococcus fagi sp.nov.

Pieces of rotten wood collected in the forest were screened for the presence of yeasts. In spring time 3 tree species were sampled, followed by 9 species in summer. Yeast strains were identified by traditional methods. Identifications were confirmed by sequencing of ribosomal DNA in case of doubt. In total 14 yeast species of ascomycetous affiliation and 6 anamorphic basidiomycetous yeasts were isolated and identified. Most species were represented by only one strain, but Candida bertae by two and Trichosporon porosum by six strains, all from different wood samples. Three strains represented novel species, one of which is described as Cryptococcus fagi Middelhoven et Scorzetti. The type strain is CBS 9964 (JCM 13614). All strains were tested for growth on several polysaccharides as sole carbon source. Only some of these polymers supported growth of ascomycetous yeasts. Basidiomycetous yeasts assimilated soluble starch, pullulan, dextran, xylan, polygalacturonate, galactomannan and tannic acid or at least some of these. Cryptococcus podzolicus and T. porosum were the most active in this respect. None of the isolated strains grew on carboxymethyl cellulose, colloidal chitin, arabinogalactan and gum xanthan. Phenolic compounds were assimilated by several strains, belonging to the Trichosporonales and the Microbotryum and Stephanoascus/Blastobotrys clades, but not by members of the Tremellales (Cryptococcus musci excepted) and the Debaryomyces/Lodderomyces clade. Most of the ascomycetes assimilated n-hexadecane.

Alkanes↗

PubMed1992

In vitro responses of cheetah mononuclear cells to feline herpesvirus-1 and Cryptococcus neoformans.

In vitro T cell function by domestic cats and cheetahs to two common pathogens, feline herpesvirus-1 (FHV-1) and Cryptococcus neoformans, was assessed. Peripheral blood mononuclear cells (PBM) were stimulated with two strains of UV-inactivated FHV-1, whole heat-killed organisms or capsular antigen of Cryptococcus neoformans, and proliferative responses measured. As a group, cheetah PBM responded significantly poorer than domestic cat PBM when cultured with FHV-1. However, individual cheetah responses varied widely. Supplementation of cultures with exogenous interleukin 2 (IL-2) significantly increased the level of response of individual cheetahs to both strains of FHV-1. Cheetah sera contained slightly higher neutralizing antibody titers to FHV-1 than did domestic cat sera, suggesting that B cells function adequately in cheetahs. When stimulated with Cryptococcus neoformans, both species had similar incidences of positive proliferative responses. These data demonstrate that cheetahs exhibit heterogeneous responses to specific antigens, similar to domestic cats. However, a lower group response to FHV-1 in cheetahs suggests species differences occur. In addition, level of variability in major histocompatibility complex (MHC) class I-like genes, as determined by Southern blot hybridization, does not appear to correlate with a uniform response in in vitro functional assays. Therefore, additional mechanisms influence the final outcome of the immune response.

Acinonyx↗

PubMed1982

Beta-Xylosidases and a nonspecific wall-bound beta-glucosidase of the yeast Cryptococcus albidus.

Cryptococcus albidus grown on wood xylans possesses a soluble intracellular beta-xylosidase (EC 3.2.1.37) as an additional constituent of the xylan-degrading enzyme system of this yeast. The enzyme attacks linear 1,4-beta-xylooligosaccharides in an exo-fashion, liberating xylose from the non-reducing ends. The activity of the enzyme increases in the cells during growth on xylan and incubation with xylobiose or methyl beta-D-xylopyranoside which are the best inducers of extracellular beta-xylanase (EC 3.2.1.8). Various alkyl-,alkyl-1-thio- and aryl beta-D-xylopyranosides were excellent inducers of a different beta-xylosidase of Cryptococcus albidus. This enzyme is localized outside the plasma membrane and is principally associated with cell walls. Unlike the soluble intracellular beta-xylosidase, the wall-bound enzyme does not hydrolyze xylooligosaccharides. Evidence has been obtained that beta-xylosidase activity in the cell walls is not due to the presence of a specific aryl beta-xylosidase, but is exhibited by a nonspecific beta-glucosidase (EC 3.2.1.21) inducible by beta-D-xylopyranosides. The ratio of beta-glucosidase and beta-xylosidase activity in the cells and isolated cell walls from yeast induced by various beta-xylopyranosides and beta-glucopyranosides was very similar. Both wall-bound activities were inhibited in a similar pattern by inhibitors of beta-glucosidases, 1,5-gluconolactone and nojirimycin. This bifunctional enzyme does not bear any relationship to the utilization of xylans in Cryptococcus albidus.

Cell Wall↗

PubMed2006

Cryptococcus stepposus, a new filobasidiaceous yeast species found in the Prioksko-terrasny biosphere reserve in Russia.

Mycocinotyping of cryptococci from the Prioksko-terrasny reserve (Russia) has revealed three strains that have a unique mycocin-sensitivity profile. Sequencing results of the D1/D2 domain of the 26S rDNA and of the complete ITS region placed them in the Floriforme clade of the Filobasidiales lineage (Hymenomycetes). The three strains had identical sequences, which differed from those of known Filobasidium and Cryptococcus species. A novel species named Cryptococcus stepposus (type strain VKM Y-2918) is proposed to accommodate these isolates. Physiological characteristics distinguishing the novel species from other Cryptococcus species in the Floriforme clade are presented.

Cryptococcus↗

PubMed1999

Polyphasic taxonomy of a novel yeast isolated from antarctic environment; description of Cryptococcus victoriae sp. nov.

In 1992 some samples of mosses, lichens and soils were collected from Botany Bay, Southern Victoria Land (77 degrees 01' S 162 degrees 32' E) and, as a result of a routine screening programme some yeasts were isolated. One of them, designated as strain G5, showed marked differences when compared to other antarctic yeasts. According to morphological and physiological characteristics, we were able to identify the strain G5 as a yeast belonging to the genus Cryptococcus. Some characteristics of this genus are the growth response to myo-inositol, celobiose, raffinose and D-glucuronate, no-fermentation, the absence of mycelium and pseudomycelium, asexual reproduction, Diazolium blue B test (DBB) and urea hydrolisis positive and the growth without vitamines. This strain (G5) formed cream colonies of slimy appearance with cells of 3 x 2 microns in size, that grew between 4 degrees C and 20 degrees C. The G + C content of strain G5 was 50.3 mol%. The molecular characterization by whole-cell proteins and RFLP analysis of the 5.8S rRNA gene and the two ribosomal internal transcribed spacers (5.85-ITS region), revealed that this strain was different from other antarctic species of this genus. The phylogenetic tree deduced from the 5.8S rRNA gene sequence showed the strain G5 as a member of the genus Cryptococcus, clearly separated from other basidiomycetous yeasts. On the basis of the physiological, genotypical and phylogenetical data, the new isolate G5 was described as Cryptococcus victoriae, sp. nov., with the type strain G5 (= CECT 11114).

Base Sequence↗

PubMed2000

Cryptococcus adeliensis sp. nov., a xylanase producing basidiomycetous yeast from Antarctica.

Cryptococcus adeliensis sp. nov. (CBS 8351) is described based on phenotypic characteristics and molecular sequence analysis of the D1/D2 large subunit and internal transcribed spacer regions of the ribosomal DNA. Molecular comparisons include species closely related to Cryptococcus albidus and several species isolated from the Antarctic. C. adeliensis, which has a cold-adapted xylanase, was isolated from Terre Adelie, Antarctica. ATCC 34633, which has a mesophilic xylanase, was identified as Cryptococcus albidosimilis.

Antarctic Regions↗

PubMed2001

Decaying wood in tree trunk hollows as a natural substrate for Cryptococcus neoformans and other yeast-like fungi of clinical interest.

The occurrence of Cryptococcus neoformans var. neoformans and other yeast-like fungi of clinical interest in decaying wood inside tree trunk hollows, bark and other plant materials is reported. The var. neoformans was isolated from 3 of 45 (6.6%) wood and one of 390 Eucalyptus bark samples. Two of the positive wood samples came from a tree trunk hollow of Butea monosperma (Family: Papilionaceae) growing in Roshan Ara Garden, Old Delhi whereas the third was from a trunk hollow of Tamarindus indica (Family: Papilionaceae) growing outside of Talkatora Garden, New Delhi. The solitary positive Eucalyptus bark sample originated from Amritsar. The isolations of var. neoformans from decaying wood inside trunk hollows of B. monosperma and T indica constitute the first record of the natural occurrence of this pathogen in association with these trees. The observation reinforces the recent evidence for decaying wood inside trunk hollows of some trees to be a new natural habitat of the variety neoformans. Besides, in consonance with their essentially saprobic character, a number of other yeast-like fungi were sporadically isolated. This includes, Cryptoccus laurentii, Cryptococcus albidus, Candida lusitaniae, C. guilliermondii, C. krusei, C. tropicalis, C. zeylanoides, Trichosporon cutaneum, Rhodotorula mucilaginosa, R. glutinis, Geotrichum capitatum, G. klebahnii and Sporobolomyces salmonicolor. Cryptococcus neoformans var. gattii was not found in any of the 702 samples of plant materials, including the bark and detritus of Eucalyptus camaldulensis and E. tereticornis trees. A more extensive environmental survey, covering divergent climatic regions, is warranted to identify the natural reservoirs of var. gattii in India.

Cryptococcus neoformans↗

PubMed2004

The first isolation of Cryptococcus neoformans from Eucalyptus trees in South Aegean and Mediterranean Regions of Anatolia in Turkey despite Taurus Mountains alkalinity.

Eucalyptus trees are widespread in subtropical parts of Turkey that have alkaline environments due to the soil structure of Taurus Mountains. In this study, the existence of Cryptococcus neoformans in eucalyptus trees in the South Aegean and Mediterranean Regions of Anatolia, Turkey, was screened between March 1998 and September 2002. Only one strain of Cryptococcus neoformans var. grubii (Serotype A) was isolated from 1175 eucalyptus samples including debris and flowers in culture by Guizotia abyssinica agar. The environmental niche of the isolate was Eucalyptus camaldulensis Dehn in the Gokova Region, in the western part of the Taurus Mountains. In this study, the existence of Cryptococcus neoformans was shown in the eucalyptus flora of Turkey despite the alkaline soil condition.

Animals↗

PubMed2002

RNA interference in the pathogenic fungus Cryptococcus neoformans.

Cryptococcus neoformans is a pathogenic fungus responsible for serious disease in immunocompromised individuals. This organism has recently been developed as an experimental system, with initiation of a genome project among other molecular advances. However, investigations of Cryptococcus are hampered by the technical difficulty of specific gene replacements. RNA interference, a process in which the presence of double-stranded RNA homologous to a gene of interest results in specific degradation of the corresponding message, may help solve this problem. We have shown that expression of double-stranded RNA corresponding to portions of the cryptococcal CAP59 and ADE2 genes results in reduced mRNA levels for those genes, with phenotypic consequences similar to that of gene disruption. The two genes could also be subjected to simultaneous interference through expression of chimeric double-stranded RNA. Specific modulation of protein expression through introduction of double-stranded RNA thus operates in C. neoformans, which is the first demonstration of this technique in a fungal organism. Use of RNA interference in Cryptococcus should allow manipulation of mRNA levels for functional analysis of genes of interest and enable efficient exploration of genes discovered by genome sequencing.

Carboxy-Lyases↗

PubMed2003

Cryptococcus surugaensis sp. nov., a novel yeast species from sediment collected on the deep-sea floor of Suruga Bay.

A novel species of the genus Cryptococcus was isolated from sediment collected on the deep-sea floor of Suruga Bay, Japan. Nucleotide sequences of 18S rDNA, internal transcribed spacers, 5.8S rDNA and the D1/D2 region of 26S rDNA of strain SY-260(T) suggested affinities to a phylogenetic lineage that includes Cryptococcus luteolus. Comparisons of the rDNA sequences of each region clarified that strain SY-260(T) is related distantly to Bullera coprosmaensis and Bullera oryzae, but is distinct at the species level. As ballistoconidia and sexual reproduction were not observed in strain SY-260(T), this strain is described as Cryptococcus surugaensis sp. nov. (type strain, SY-260(T)=JCM 11903(T)=CBS 9426(T)).

Cryptococcus↗

PubMed2004

A novel psychrotolerant member of the hymenomycetous yeasts from Antarctica: Cryptococcus watticus sp. nov.

Soil, snow and organic material, collected in November 1997 from the Vestvold Hills, Davis Base, Antarctica, were screened for yeasts. Two isolates, which were shown to be indistinguishable by rDNA sequencing and protein analysis by SDS-PAGE, are described in this communication as a novel species, Cryptococcus watticus sp. nov. (type culture, CBS 9496T=NRRL Y-27556T). Sequence analyses of the 26S rDNA D1/D2 region placed C. watticus in the hymenomycetous yeasts in a cluster with Holtermannia corniformis and Cryptococcus nyarrowii. This species has been allocated to the genus Cryptococcus on the basis of physiological and morphological characteristics.

Antarctic Regions↗

PubMed2005

Cryptococcus taeanensis sp. nov., a new anamorphic basidiomycetous yeast isolated from a salt farm.

Cryptococcus taeanensis, a new anamorphic yeast species originating from a salt farm on the Taean peninsula in Korea, is described. Strain 3-12(T) grew by budding, contained ubiquinone Q-10 and xylose in cell hydrolysates, utilized d-glucuronate and did not ferment D-glucose. A molecular phylogenetic analysis based on the large-subunit rRNA D1/D2 domain and ITS region sequences placed C. taeanensis near Auriculibuller fuscus and Bullera japonica, recently proposed taxa of the Tremellales. However, these species were distinguishable based on standard physiological tests used for yeast identification, with characteristics including the assimilation of L-sorbose, absence of ballistoconidia, no arbutin hydrolysis and no growth in the presence of 0.01 % cycloheximide. The isolate exhibited the typical physiology of the genus Cryptococcus Vuillemin, but its large-subunit rRNA D1/D2 domain sequence was clearly distinct from previously described species in the genus. Therefore, on the basis of these results, Cryptococcus taeanensis sp. nov. is proposed; the type strain is 3-12(T) (=KCTC 17149(T) = CBS 9742(T)).

Antifungal Agents↗

PubMed1982

Japanese summer-type hypersensitivity pneumonitis: studies using Cryptococcus antigen.

Sixty-six patients, diagnosed as Japanese summer-type hypersensitivity pneumonitis at Osaka Prefectural Habikino hospital between 1973 and 1980, were studied. The diagnosis was based on the clinical features and summer-seasonal nature of the disease. The presence of an aetiological agent within patients' home environment was suggested by the recurrence of acute symptoms of high fever, cough and dyspnoea 5-8 hr after coming home from hospital, and by spontaneous improvement on leaving home. Immunological studies revealed the presence of anti-Cryptococcus antibody in sixty-four of sixty-five patients' sera, by indirect immunofluorescence against Cryptococcus neoformans. Precipitating antibody against culture supernatant protein-antigen of Cr. neoformans was detected in more than 80% of sera obtained from patients during the active stage of the disease. The positive result on inhalation provocation-challenge, using culture supernatant protein-antigen, suggested that Cr. neoformans or antigenically related Cryptococcus species may cause Japanese summer-type hypersensitivity pneumonitis.

Adolescent↗

PubMed1994

Encapsulation of Cryptococcus neoformans regulates fungicidal activity and the antigen presentation process in human alveolar macrophages.

Our previous studies have shown that unstimulated alveolar macrophages (AM) play a predominant role as antigen-presenting cells in Cryptococcus neoformans infections, while the function as effector cells seems to be of minor relevance. The present study focuses on the role of encapsulation of C. neoformans on fungicidal activity and the antigen presentation process of AM. Fungicidal activity in unstimulated AM occurs to a higher degree when the acapsular strain is employed, but this is impaired compared with other natural effectors, such as peripheral blood monocytes (PBM) and polymorphonuclear (PMN) cells. Cryptococcus-laden AM also induce a higher proliferative response in autologous CD4+ lymphocytes when the acapsular strain is used compared with encapsulated yeast. The enhanced blastogenic response is, in part, ascribed to an augmented IL-2 production by T cells. In addition, higher levels of interferon-gamma (IFN-gamma), but not IL-4, are produced by the responding T cells, when the acapsular strain is used compared with the encapsulated yeast. Moreover, IFN-gamma is able to induce fungicidal activity in AM against the encapsulated yeast and augments killing activity of the acapsular strain. This phenomenon is not mediated by nitric oxide production, but is correlated with an enhancement of fungicidal activity of cytoplasmic cationic proteases. We speculate that encapsulation of C. neoformans could down-regulate the development of the immune response mediated by Cryptococcus-laden AM at lung level.

Adult↗

PubMed2002

Detection of Cryptococcus neoformans DNA in tissue samples by nested and real-time PCR assays.

Two PCR protocols targeting the 18S rRNA gene of Cryptococcus neoformans were established, compared, and evaluated in murine cryptococcal meningitis. One protocol was designed as a nested PCR to be performed in conventional block thermal cyclers. The other protocol was designed as a quantitative single-round PCR adapted to LightCycler technology. One hundred brain homogenates and dilutions originating from 20 ICR mice treated with different azoles were examined. A fungal burden of 3 x 10(1) to 2.9 x 10(4) CFU per mg of brain tissue was determined by quantitative culture. Specific PCR products were amplified by the conventional and the LightCycler methods in 86 and 87 samples, respectively, with products identified by DNA sequencing and real-time fluorescence detection. An analytical sensitivity of 1 CFU of C. neoformans per mg of brain tissue and less than 10 CFU per volume used for extraction was observed for both PCR protocols, while homogenates of 70 organs from mice infected with other fungi were PCR negative. Specificity testing was performed with genomic DNA from 31 hymenomycetous fungal species and from the ustilaginomycetous yeast Malassezia furfur, which are phylogenetically related to C. neoformans. Twenty-four strains, including species of human skin flora like M. furfur and Trichosporon spp., were PCR negative. Amplification was observed with Cryptococcus amylolentus, Filobasidiella depauperata, Cryptococcus laurentii, and five species unrelated to clinical specimens. LightCycler PCR products from F. depauperata and Trichosporon faecale could be clearly discriminated by melting curve analysis. The sensitive and specific nested PCR assay as well as the rapid and quantitative LightCycler PCR assay might be useful for the diagnosis and monitoring of human cryptococcal infections.

Animals↗

PubMed2004

Challenge of Drosophila melanogaster with Cryptococcus neoformans and role of the innate immune response.

We found that the ingestion of Cryptococcus neoformans by Drosophila melanogaster resulted in the death of the fly but that the ingestion of Saccharomyces cerevisiae or the nonpathogenic Cryptococcus kuetzingii or Cryptococcus laurentii did not. The C. neoformans protein kinase A and RAS signal transduction pathways, previously shown to be involved in virulence in mammals, also played a role in killing Drosophila. Mutation of the Toll immune response pathway, the predominant antifungal pathway of the fly, did not play a role in Drosophila defense following ingestion of the yeast. However, the Toll pathway was necessary for the clearance of C. neoformans introduced directly into the hemolymph of D. melanogaster and for the survival of systemically infected flies.

Animals↗

PubMed2006

Evidence of mRNA-mediated intron loss in the human-pathogenic fungus Cryptococcus neoformans.

Introns are a defining feature of eukaryotic genomes, though the mechanism of intron gain or loss is not well understood. Reverse transcription of mRNA followed by homologous recombination with the genome has been posited as a mechanism of intron loss, though little direct evidence of recent loss events has been described to support this model. We find supporting evidence for an mRNA-mediated mechanism of loss through comparative genome analyses that revealed a recent loss of 10 adjacent introns in a 22-exon gene in the human-pathogenic fungus Cryptococcus neoformans. We surveyed the gene structures of the entire genomes of Cryptococcus gattii, which diverged from the C. neoformans lineage 37 million years ago (Mya), and C. neoformans var. grubii and var. neoformans, which diverged 18 Mya. Our comparison revealed greater than 99.9% intron conservation, with evidence from 20 genes showing evidence of intron loss, but no convincing evidence of intron gain. Our findings confirm that Cryptococcus introns have been quite stable over recent evolutionary time, with occasional mRNA-mediated intron loss events.

Biological Evolution↗