Cryptococcus Diffluens Research Articles

The basidiomycetous yeasts Cryptococcus diffluens and C. liquefaciens colonize the skin of patients with atopic dermatitis.

Our previous research showed that lipophilic yeasts, Malassezia species, colonize the skin of patients with atopic dermatitis (AD) at a high frequency. In this study, we found that two basidiomycetous yeasts, Cryptococcus diffluens and C. liquefaciens, colonize the skin significantly more frequently in AD patients than in healthy subjects. Transparent dressings were applied to the skin of 36 AD patients and 30 healthy subjects and then transferred onto Sabouraud dextrose agar. Colonies recovered from the medium were identified by DNA sequence analysis of internal transcribed spacer regions and the D1/D2 26S rRNA gene. C. diffluens and C. liquefaciens were isolated from 42% (15/36) and 33% (12/36) of AD patients and from 20% (6/30) and 20% (6/30) of healthy subjects, respectively. In addition, fungal DNA was extracted directly from the dressings and amplified in a specific nested PCR assay. C. diffluens and C. liquefaciens DNA were detected in dressings from 97% (35/36) and 86% (31/36) of the AD patients and 47% (14/30) and 37% (11/30) of the healthy subjects, respectively. These findings show that Malassezia spp. are not the only yeasts that colonize the skin of AD patients; Cryptococcus spp. also are present in a high proportion of patients. The role of these microorganisms in AD is as yet unknown, but the current findings, in combination with previous results, indicate that C. diffluens, C. liquefaciens, M. globosa, and M. restricta together colonize the skin surface of AD patients at a high frequency.

Effect of Temperature on Saprophytic Cryptococci: Observations Relating to Wall Biosynthesis at Non-permissive Growth Temperatures

Summary: An attempt was made to define the basis of temperature-induced aberrant wall biosynthesis in Cryptococcus diffluens. A quantitative determination of the sulphydryl content of the cell surface of C. diffluens as an index of a protein disulphide reductase activity failed to reveal differences between cells cultured at permissive and non-permissive growth temperatures. Assays of β-1,3-exo-glucanase showed no abnormal activities which could be responsible for the temperature-induced aberrations. Cryptococcus diffluens excreted low molecular weight compounds non-specifically: UMP and AMP were the predominant nucleotides excreted. Uridine diphosphoglucose, a precursor of glucan biosynthesis, was accumulated and excreted by C. diffluens at non-permissive but not at permissive growth temperatures. A correlation exists between the rate of yeast multiplication at permissive temperatures and the extent of residual growth upon subsequent exposure to a non-permissive temperature.

Effect of temperature on saprophytic cryptococci: temperature-induced lysis and protoplast formation.

Summary: The saprophytic cryptococci, Cryptococcus diffluens, Cryptococcus laurentii and Cryptococcus albidus which are characterized by inability to grow at 37 °C and above, were shown to lyse at non-permissive growth temperatures. Incorporation of radioactive precursors of protein, RNA and DNA by C. diffluens suggested that protoplasmic growth continued at 37 °C. Incorporation of 20% sucrose in the growth medium retarded lysis at the non-permissive temperature and direct microscopic examination of cells under these conditions revealed aberrations in the walls and protoplast extrusion. Similar wall aberrations which were induced by the inhibitor 2-deoxyglucose suggest that aberrant wall biosynthesis occurs at non-permissive growth temperatures.

Studies on Himalayan yeasts and molds. IV. Several asporogenous yeasts including two new taxa of Cryptococcus

Thirteen strains referred to six asporogenous yeast species were isolated from soil, dung, and forest humus samples collected in Bhutan. The following species, including two new taxa of Cryptococcus, were recovered: Cryptococcus albidus,Cryptococcus bhutanensis sp. nov., Cryptococcus diffluens,Cryptococcus himalayensis sp. nov., Torulopsis Candida, and Rhodotorula glutinis.

The utilization of flavonoid compounds by yeasts and yeast-like fungi.

Three hundred cultures of yeasts and yeast-like fungi were tested for their ability to metabolize flavonoid compounds. Rutin, quercitrin, taxifolin, and naringin were used by strains of Pullularia and by the asporogenous yeasts Cryptococcus albidus and Cryptococcus diffluens. Catechin and 5, 7-dihydroxyiso-flavone were not used by any of the cultures tested.The utilization of flavonoid compounds was dependent upon the nutritional complexity of the medium used. When a complex organic nitrogen source was used in the medium, not only were quercetin glycosides metabolized at a faster rate but yeasts, which were inactive on a synthetic medium, utilized varying amounts of the glycosides. The aglycone quercetin was utilized only in the presence of organic nitrogen compounds. Culture filtrates were inactive but cell-free extracts of a Pullularia sp. and of strains of C. albidus and C. diffluens degraded rutin, in the presence of air, to glucose, rhamnose, protocatechuic acid, phloroglucinol carboxylic acid, and carbon monoxide. The metabolism of flavonol glycosides by yeasts is discussed as a taxonomic characteristic and the pathway used is compared to the known microbiological routes for the utilization of these compounds.

Cryptococcus症の研究

1. The rabbits of a commercial stock were immunized by the intravenous inoculation of live Cryptococcus neoformans of the Ishino strain at the concentration of 1 mg per cc. The antigen was injected thrice a week for 3 consecutive weeks. The immune serum with the agglutination titer of 1:1, 024 against the homologous organism was obtained 5 weeks after the last inoculation. 2. The tube agglutination test with this immune serum gave the following agglutination titers, 1:128 against Cryptococcus neoformans (C2-4 strain), 1:32 against Cryptococcus diffluens and 1:8 against Torulopsis sake and Torulopsis pinus, respectively. 3. The slide agglutination test showed that the differentiation between Cryptococcus species and Torulopsis species was made if the antiserum was diluted to 1:10. 4. The γ-globulin concentation of the fluorescein isothiocyanate-labeled antibody solution was 0.52% which was completely able to differentiate between Torulopsis pinus and Cryptococcus species if diluted to 1:8. The fluorescent antibody technic was able to afford us making a diagnosis without difficulty when the fluorescein isothiocyanate-labeled antibody was prepared from the immune serum with agglutination titer as high as possible and diluting it to some extent. (In the author's experiment, diluting to 0.0165% of γ-globulin was most effective.)

Yeasts from the Bovine Caecum

SUMMARY: From the caeca of 252 adult bovines 131 yeast strains were isolated, distributed as shown (in brackets) among the following species: Saccharomyces cerevisiae (12), S. chevalieri (3), S. drosophilarum (3), S. fragilis (1), Pichia bovis (1), P. membranaefaciens (3), P. fermentans (3), Cryptococcus diffluens (1), Torulopsis glabrata (4), Torulopsis sp. (2), Candida tropicalis (45), C. parapsilosis (3), C. krusei (33), C. macedoniensis (1), C. utilis (1), C. bovina (1), Trichosporon cutaneum (5). Candida albicans was not isolated. The apparent absence of C. albicans from the bovine intestinal tract may explain the rareness of oral and intestinal moniliasis in bovines. Infection in certain forms of yeast mastitis (caused neither by C. albicans nor by Cryptococcus neojormans) may be derived from the intestinal tract. Descriptions and Latin diagnoses of Pichia bovis n.sp. and Candida bovina n.sp. are given.

A quantitative study of air-borne fungus spores in Dunedin, New Zealand

By means of culture plates exposed in a Manning slit sampler, a quantitative survey of air-borne moulds has been made between March 1953 and April 1954 in and just outside a building in the city area of Dunedin, New Zealand. There was little difference between the yields from indoor and outdoor air. The average count throughout the year was 13·9 colonies per cubic foot. Lowest yields were obtained during the winter months (an average of 5·9 colonies per cu.ft.) and highest during the summer (25·1 colonies per cu.ft.). Cladosporium occurred most frequently (42·9 %), and Penicillium was the next most commonly encountered mould (34·2 %). Air-borne yeasts in the Dunedin city area were also surveyed between February 1953 and April 1954 by means of culture plates exposed in a slit sampler. The average density of viable yeasts was found to be one to two cells or clumps of cells to 2 cu.ft. of air. Almost all the isolates belonged to four major groups, Debaryomyces species (including imperfect forms of this genus), nonpathogenic Cryptococcus species, the Sporobolomyces-Rhodotorula group, and the yeast-like phase of Cladosporium. Debaryomyces kloeckeri and Cryptococcus diffluens were the species most commonly isolated. Experiments have suggested that air-borne yeasts may be selected by their ability to withstand the effects of drying and ultra-violet radiation.