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PubMed1984

Pulmonary cell response in mice following intranasal instillation with Cryptococcus neoformans.

Cryptococcus neoformans was instilled intranasally into mice which were sacrificed to determine the fate of instilled cryptococci and the pulmonary cellular response. During the first 12 h, instilled cryptococci decreased significantly in numbers and did not disseminate to extrapulmonary sites. There was a transient increase in neutrophils which may have been due to an influx of bacteria which accompanied the process of intranasal instillation.

Acinetobacter↗
PubMed1992

Growth of Cryptococcus neoformans in a thiamine-free medium.

The growth of Cryptococcus neoformans in a minimal liquid synthetic medium with or without thiamine (10 micrograms/ml) was investigated. In these media the presence or absence of thiamine had no effect on the development of C. neoformans. To check these results, we performed a series of experiments on a solid form of the minimal synthetic medium. In this study a series of six serial transfers were carried out to starve the cells of nutrients that may have been carried over from their growth on rich media. In each of the transfers on the solid synthetic medium, C. neoformans showed a similar and scarce growth. This finding indicates that C. neoformans could be autotrophic in respect to thiamine.

Cryptococcus neoformans↗
PubMed1992

Cryptococcus neoformans varieties as agents of cryptococcosis in Brazil.

The study of the clinical isolates of Cryptococcus neoformans from 83 Brazilian patients with disseminated cryptococcosis showed that 75 were C. neoformans var. neoformans and 8 were var. gattii. Twenty-seven isolates were serotyped; all 19 var. neoformans were serotype A and all 8 var. gattii were serotype B. The correlation of the varieties of C. neoformans with the presence or not of hosts predisposing conditions to the mycosis showed that: (1) cryptococcosis caused by gattii variety occurred in 7 (58.3%) of the 12 nonimmunosuppressed patients, and (2) cryptococcosis caused by neoformans variety occurred in 65 (98.5%) of the 66 AIDS patients and in all 5 patients with other immunosuppressive conditions. The comparison of the distribution of the gattii and neoformans varieties between the nonimmunosuppressed and immunosuppressed patients showed a significant statistical difference (p < 0.01).

Acquired Immunodeficiency Syndrome↗
PubMed1991

Cryptococcus yarrowii sp. nov., a novel yeast species from Portugal.

A novel species of the basidiomycetous genus Cryptococcus is described as Cr. yarrowii based on the study of an isolate from a decayed mushroom collected in Portugal. DNA-DNA homology with the type strain of the phenotypically similar species Cr. albidus was 10 +/- 2%.

Cryptococcus↗
PubMed1988

Carbohydrate patterns of Candida, Cryptococcus and Rhodotorula species.

Within the genus Candida three distinct groups are recognized on the basis of carbohydrate patterns of intact whole cell hydrolyzates. In the first, ascomycetous, group mannose is dominant, while rhamnose, fucose and xylose are absent; this is indicative of an affinity with endomycetous families. Among the basidiomycetous representatives, two groups can be recognized. One group is usually characterized by the presence of xylose and has a low mannose content. The pattern is typical for Cryptococcales and Tremellales (e.g., Cryptococcus, Trichosporon, Bullera and Tremella). The other basidiomycetous group is characterized by the presence of fucose and/or rhamnose with significant amounts of mannose. This pattern is characteristic for Sporobolomycetaceae.

Candida↗
PubMed1995

Partial conversion of cinnamic acid into styrene by growing cultures and cell-free extracts of the yeast Cryptococcus elinovii.

Cultures of Cryptococcus elinovii CBS 7051 grown at the expense of cinnamic acid as the sole source of carbon and energy partially converted this substrate into styrene. The latter is toxic and eventually kills the culture. Cell-free extracts of cultures grown on cinnamic acid produced styrene from cinnamate. Other basidiomycetous yeasts tested did not produce styrene from cinnamic acid.

Cell Death↗
PubMed1994

Effect of amphotericin B on the lipids of five different strains of Cryptococcus neoformans.

Cells of five strains of Cryptococcus neoformans were obtained for partial analysis of lipid composition. Quantitative analysis of lipids and sterols were completed, as well as qualitative analysis of sterols by thin-layer chromatography and by the ultraviolet spectra. Such determinations were made on cells cultured in the absence and presence of amphotericin B at sub-MIC (minimal inhibitory concentration) levels. Marked alterations of the lipid and sterol contents were observed in the amphotericin B-treated cells. Moreover, ergosterol disappeared in these antibiotic-exposed cells. It is concluded that amphotericin B altered the lipid profiles, especially sterols of C. neoformans.

AIDS-Related Opportunistic Infections↗
PubMed1993

The isolation of Cryptococcus neoformans from pigeon droppings and serotyping of naturally and clinically sourced isolates in China.

This is the first report on the isolation of Cryptococcus neoformans from pigeon droppings in China and their serotypes. C. neoformans colonies which produced brown colonies on caffeic acid-cornmeal agar were found in Twenty-five out of thirty-six samples of pigeon droppings. Fifty-one colonies randomly picked from the positive samples were identified as C. neoformans by a commercially available kit for carbon source assimilation test and Christensen's urea agar. Forty (78%) out of the 51 strains were serotyped as A and 11 (22%) as AD. At the same time, seventeen out of nineteen clinical isolates were serotyped as A and 2 as B. There are three findings in our results. One is that only C. neoformans var. neoformans strains could be isolated from pigeon droppings, although the variety gattii strains were found in the clinical isolates obtained in the same geographic site in China. The second is that serotype A strains were most frequently seen in natural and clinical materials in the southeast part of China, and serotype AD strains were isolated in pigeon droppings but not in clinical materials. The third is that the coexistence of serotype A and AD cells of C. neoformans strains in same samples of pigeon droppings were observed.

Animals↗
PubMed1993

Turbidimetric and visual criteria for determining the in vitro activity of six antifungal agents against Candida spp. and Cryptococcus neoformans.

The drug concentration which inhibited 50% of growth (IC50), the lowest drug concentration at which growth was less than 30% of that in a positive control well (IC30), the visual minimal inhibitory concentration (MIC), and the minimum fungicidal concentration (MFC), were applied to study the effects of fluconazole, itraconazole, ketoconazole, miconazole, flucytosine, and amphotericin B against 36 isolates of Candida spp. and Cryptococcus neoformans by a broth microdilution technique. When the recommendations established by the NCCLS Subcommittee on Antifungal Susceptibility Tests were applied for the visual reading of the microplates, the results were comparable with those obtained by the turbidimetric methods. Differences between MICs and IC30s were observed with miconazole against strains of C. glabrata (p = 0.014) and with flucytosine against strains of C. neoformans (p = 0.041). Differences between MICs and IC50s were observed with fluconazole against strains of C. albicans (p = 0.027), C. tropicalis (p = 0.046), and C. neoformans (p = 0.041); with miconazole against strains of C. glabrata (p = 0.014); and with amphotericin B against strains of C. parapsilosis (p = 0.025). Ten additional isolates of C. albicans from AIDS patients suffering from recurrent episodes of oral candidiasis and clinically resistant to fluconazole also were included in this study. The MICs of fluconazole of these strains were significantly higher than those of the control group (p = 0.003). When the turbidimetric parameters were applied for testing the in vitro activity of fluconazole against the above isolates, both IC30 and IC50 were capable of discriminating the strains of the two groups (p = 0.002, p = 0.001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1994

In vivo depletion of murine CD8 positive T cells impairs survival during infection with a highly virulent strain of Cryptococcus neoformans.

Cell-mediated immunity plays an important but incompletely understood role in host defense against Cryptococcus neoformans. Because of their multiple capacities as cytokine-secreting cells, cytotoxic cells, and antigen-specific suppressor cells, CD8 positive T lymphocytes could potentially either enhance or impair host defense against C. neoformans. To determine whether CD8 T cells enhance or inhibit host defence during an infection with a highly virulent strain of C. neoformans, we examined the effect of in vivo CD8 cell depletion on survival and on the number of organisms in mice infected by either the intratracheal or intravenous routes. Adequacy of depletion was confirmed both phenotypically and functionally. Regardless of the route of infection, we found that survival of mice depleted of CD8 T cells was significantly reduced compared to undepleted mice. Surprisingly, however, CD8 depletion did not alter organism burden measured by quantitative CFU assay in mice infected by either route. These data demonstrate that CD8 positive T cells participate in the immune response to a highly virulent strain of C. neoformans. By contrast to minimally virulent isolates that do not cause a life threatening infection, the immune response to a highly virulent isolate does not alter the burden of organisms, but does enhance host defense as it is necessary for the optimal survival of infected mice.

Animals↗
PubMed1993

Ultrastructural study of Cryptococcus neoformans by quick-freezing and deep-etching method.

The three-dimensional ultrastructure of Cryptococcus neoformans was studied by quick-freezing and deep-etching (QF-DE) method. C. neoformans, strain CDC551, was cultured on agar. The viable yeast cells (10(7) cells) were inoculated into each mouse from the tail vein. Three weeks after the inoculation, the brains of the mice were perfused with fixatives, quickly frozen, freeze-fractured, deeply etched and rotary shadowed with platinum and carbon. In addition, the viable cells of C. neoformans on agar were picked up and quickly frozen, and replica membranes were prepared as described above. The ultrastructure of C. neoformans was three-dimensionally demonstrated by the QF-DE method. The capsule was composed of fine meshworks of microfibrils (10-13 nm in diameter), which were directly attached to the cell walls. The capsule of the in vivo yeasts (yeast cells in the brain lesion) was thicker than that of the in vitro yeasts (yeast cells on agar culture). At the outer part of the cell wall, a particle-accumulating layer was observed. This layer in vivo was thicker than that in vitro. Occasionally, the yeast cells were ingested by phagocytes in the mouse brain. Although the cytoplasm of such yeast cells was destroyed, the capsular meshworks were well preserved. The ultrastructure of the capsule was the same both in cultured and phagocytized yeasts in the cystic lesions of the brains. This lack of morphological changes of the capsular meshworks suggests that they are resistant to the digestion by phagocytes. This stability of capsular structures may provide one of the important pathogenic factors in cystic lesions by C. neoformans.

Animals↗
PubMed1993

A potent specific inhibitor of 6-phosphogluconate dehydrogenase of Cryptococcus neoformans and of certain other fungal enzymes.

A particular lot of the zwitterionic buffer, 2(N-morpholino) ethane sulfonic acid (MES), contained a contaminant that inhibited a number of fungal NADP-dependent dehydrogenases. Enzymes that were particularly sensitive include 6-phosphogluconate dehydrogenases from Cryptococcus neoformans and Schizophyllum commune and glucose-6-phosphate dehydrogenase from Schizophyllum commune. A number of NADP-dependent dehydrogenases of animal origin were tested and all were completely insensitive to inhibition except for rat liver 6-phosphogluconate dehydrogenase, which was 10-fold less sensitive than the Cryptococcal enzyme. The pattern of inhibition in all cases was linear competitive versus NADP. The inhibitor has been purified and identified as an ethylenesulfonic acid oligomer. This inhibitor holds promise as a model compound for the development of a specific antifungal agent.

Adenosine Monophosphate↗
PubMed1994

Extracellular proteolytic activity of Cryptococcus neoformans.

Eight strains of Cryptococcus neoformans var. neoformans isolated from AIDS patients in the Infectious Disease Institute, University of Turin, Italy, were examined for growth and extracellular proteolytic activity in culture with solid and liquid media. All of the strains grew well on Yeast Carbon Base (YCB) agar medium supplemented with both 0.1% (w/v) bovine serum albumin (BSA) and 0.01% (w/v) polypeptone (Pp), and produced a clear proteolytic zone around their colonies, whereas they exhibited less growth and proteolytic activity on YCB medium supplemented with BSA alone. Strain #8 with a strong proteolytic activity was cultured in three different liquid media. Its growth was limited in YCB medium supplemented with 0.1% BSA, but was moderate in that with 0.01% Pp. Enhanced growth was supported by the addition of both BSA and Pp to the YCB medium. The relative value of the final cellular yields obtained with the above YCB-0.1% BSA, YCB-0.01% Pp and YCB-0.1% BSA-0.01% Pp media was approximately 1:10:20. In the culture with YCB medium containing both BSA and Pp, a rapid decrease in the amount of BSA was demonstrated by a spectrophotometric assay and gel electrophoresis of the culture supernatant after the log-to-stationary phase. The proteolytic activity in the culture supernatant became detectable after the log phase when tested with skim milk agarose plates. These results allowed us to conclude that Cr. neoformans var. neoformans is able to secrete protease and to utilize protein as a source of nitrogen.

Cryptococcus neoformans↗
PubMed1994

Antifungal properties of essential oils and their main components upon Cryptococcus neoformans.

Cryptococcus neoformans opportunistic fungus met in the last phasis of AIDS is inhibited in vitro by several essential oils on natural volatile compounds. The minimal inhibitory concentration may reach 100 microliters/l and minimal fungicidal concentration 200 microliters/l with Palmarosa or Cinnamon oils. Among phenolic compounds, thymol and carvacrol are most fungitoxic. Terpenoids, citral, geraniol, and citronellol show best activities.

AIDS-Related Opportunistic Infections↗
PubMed1995

Isolation of Cryptococcus neoformans var. neoformans from bird droppings, fruits and vegetables in Mexico City.

The presence of Cryptococcus neoformans in various natural sources, such as bird droppings, fruits and vegetables, was investigated. A total of 711 samples were analyzed; C. neoformans var. neoformans was isolated from seven out of 74 bird droppings (9.5%), with parrots as one of the most significant sources. Fruits were positive in 9.5% of the 169 samples studied, specially citrus fruits, particularly grapefruit, in which the highest frequency was found. From the 468 vegetable samples, only 20 were positive (4.2%). It is emphasized that five of the positive vegetables species are autochthonous to Mexico: avocado (Nectandra salicifolia), beet (Beta vulgaris var. quinopodiace), chayote (Sechium edule), stringbean (Cassia sp), and nopal (Opuntia ficus-indica).

Animals↗
PubMed1993

Identification of the perfect state of Cryptococcus neoformans from 195 clinical isolates including 84 from AIDS patients.

Filobasidiella neoformans is the teleomorphic state of Cryptococcus neoformans and it is a heterothalic. The purpose of this study was to establish the proportions of each mating types (a, alpha) from among 195 strains of C. neoformans isolated from clinical material. The culture medium used was sunflower agar. Cultures were incubated at 20-22 degrees C for 15 days and observed periodically for one month. Non-reactive strains were mated several times with different reactive strains. Under these conditions 96.8% of the strains were found to be reactors. Among both varieties of C. neoformans, mating type alpha was found to have the highest frequency of 95% in the variety neoformans and 84% in the variety gattii. These results showed a higher reactivity in comparison with other investigators. This difference could be due to the medium used or to repeated mating with different reactive tested strains.

AIDS-Related Opportunistic Infections↗
PubMed1994

Serotypes and mating types of clinical strains of Cryptococcus neoformans isolated in Taiwan.

Twenty-one strains of Cryptococcus neoformans isolated from patients in Taiwan were characterized for serotypes and mating types. Slide agglutination test was performed with 8 factor-specific sera (Iatron Company, Japan) to determine the serotypes. Wheat bran agar (WBA) and malt extract agar (MEA, Wickerham) media were used for the mating tests. Twenty of the isolates were of serotype A, and one was serotype B. Except for 2 strains of serotype A, all of the serotype A strains mated with Filobasidiella neoformans var. neoformans, mating type a. The only serotype B strain mated with F. neoformans var. bacillispora mating type a in MEA medium. These data revealed the low prevalence (1/21; 4.8%) of C. neoformans var. gattii in Taiwan, a subtropically located isoland.

Cryptococcosis↗