• Archives of Pharmacal Research
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• v.25 no.3
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• pp.215-228
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• 2002

It is now more than two decades since the AIDS epidemic began with a cluster of Pneumocystis carinii pneumonia (PCP) in a community of homosexual men. Since then, many other infections have been characterized as opportunistic infections secondary to HIV infection. These include, but are not limited to, infections with Toxoplasma gondii, Cytomegalovirus (CMV), Mycobacterium avium complex (MAC), and Cryptococcus neoformans. Over the last two decades, there have been dramatic improvements in diagnosis, prevention and treatment of all these infections. As a result, in North America and Western Furope the rates of opportunistic infections secondary to AIDS have decreased substantially. We will review these common opportunistic infections below.

• The Korean Journal of Cytopathology
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• v.4 no.2
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• pp.156-159
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• 1993

Cryptococcosis is a systemic mycosis that most often involves the central nervous system, followed by subclinical or symptomatic pulmonary involvement. We describe a case of unsuspected pulmonary cryptococcosis in a 69-year-old woman, diagnosed by sputum cytology. Sputum smears revealed numerous yeast like organisms typical of Cryptococcus neoformans measuring from 7 to 17 um in diameter. Mucicarmine, PAS, and methenamine sliver stains showed positive reaction of capsule and cell wall of Cryptococcus neoformans.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.280.2-280
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• 1995

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.918-927
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• 2016

Cryptococcus neoformans is a life-threatening pathogenic yeast that causes devastating meningoencephalitis. The mechanism of cryptococcal brain invasion is largely unknown, and recent studies suggest that its extracellular microvesicles may be involved in the invasion process. The 14-3-3 protein is abundant in the extracellular microvesicles of C. neoformans, and the 14-3-3-GFP fusion has been used as the microvesicle's marker. However, the physiological role of 14-3-3 has not been explored. In this report, we have found that C. neoformans contains a single 14-3-3 gene that apparently is an essential gene. To explore the functions of 14-3-3, we substituted the promoter region of the 14-3-3 with the copper-controllable promoter CTR4. The CTR4 regulatory strain showed an enlarged cell size, drastic changes in morphology, and a decrease in the thickness of the capsule under copper-enriched conditions. Furthermore, the mutant cells produced a lower amount of total proteins in their extracellular microvesicles and reduced adhesion to human brain microvascular endothelial cells in vitro. Proteomic analyses of the protein components under 14-3-3-overexpressed and -suppressed conditions revealed that the 14-3-3 function(s) might be associated with the microvesicle biogenesis. Our results support that 14-3-3 has diverse pertinent roles in both physiology and pathogenesis in C. neoformans. Its gene functions are closely relevant to the pathogenesis of this fungus.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1142-1148
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• 2020

Mitochondria play a vital role in iron uptake and metabolism in pathogenic fungi, and also influence virulence and drug tolerance. However, the regulation of iron transport within the mitochondria of Cryptococcus neoformans, a causative agent of fungal meningoencephalitis in immunocompromised individuals, remains largely uncharacterized. In this study, we identified and functionally characterized Mrs3/4, a homolog of the Saccharomyces cerevisiae mitochondrial iron transporter, in C. neoformans var. grubii. A strain expressing an Mrs3/4-GFP fusion protein was generated, and the mitochondrial localization of the fusion protein was confirmed. Moreover, a mutant lacking the MRS3/4 gene was constructed; this mutant displayed significantly reduced mitochondrial iron and cellular heme accumulation. In addition, impaired mitochondrial iron-sulfur cluster metabolism and altered expression of genes required for iron uptake at the plasma membrane were observed in the mrs3/4 mutant, suggesting that Mrs3/4 is involved in iron import and metabolism in the mitochondria of C. neoformans. Using a murine model of cryptococcosis, we demonstrated that an mrs3/4 mutant is defective in survival and virulence. Taken together, our study suggests that Mrs3/4 is responsible for iron import in mitochondria and reveals a link between mitochondrial iron metabolism and the virulence of C. neoformans.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1403-1412
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• 2013

Ethanol fuel production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable development. To use this biomass, it is necessary to circumvent the physical and chemical barriers presented by the cohesive combination of the main biomass components, which hinders the hydrolysis of cellulose and hemicellulose into fermentable sugars. This study evaluated the hydrolytic capacity of enzymes produced by yeasts, isolated from the soils of the Brazilian Cerrado biome (savannah) and the Amazon region, on sugarcane bagasse pre-treated with $H_2SO_4$. Among the 103 and 214 yeast isolates from the Minas Gerais Cerrado and the Amazon regions, 18 (17.47%) and 11 (5.14%) isolates, respectively, were cellulase-producing. Cryptococcus laurentii was prevalent and produced significant ${\beta}$-glucosidase levels, which were higher than the endo- and exoglucanase activities. In natura sugarcane bagasse was pre-treated with 2% $H_2SO_4$ for 30 min at $150^{\circ}C$. Subsequently, the obtained fibrous residue was subjected to hydrolysis using the Cryptococcus laurentii yeast enzyme extract for 72 h. This enzyme extract promoted the conversion of approximately 32% of the cellulose, of which 2.4% was glucose, after the enzymatic hydrolysis reaction, suggesting that C. laurentii is a good ${\beta}$-glucosidase producer. The results presented in this study highlight the importance of isolating microbial strains that produce enzymes of biotechnological interest, given their extensive application in biofuel production.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.1-7
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• 2016

This study focused on isolation and identification of wild yeasts from soils in fields near mountains and elucidation of its yeast distribution. Several kinds of yeasts were isolated from various soils of Daejeon metropolitan city and Chungcheongnam-do in Korea and identified by BLAST search of nucleotide sequences of internal transcribed spacer (ITS) region including 5.8S rRNA and D1/D2 region of 26S rDNA. Ninety-seven strains of 20 species from 61 soil samples were isolated, of which Cryptococcus podzolicus (11 strains), Debaryomyces hansenii (6 strains), and Trichosporon asahii (6 strains) were dominant species.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.5
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• pp.393-399
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• 2001

Effects of various types of salts (commercial low salt, sea salt, refined salt, and bamboo salt) and concentrations (0, 3.0 and 5.0% ) on the growth of yeasts isolated from Kimchi were investigated. The isolated yeasts used in the study are as follows : Saccharomyces cerevisia, Sporobolomyces albo-rubescens, Issatchenkia orientalis Cryptococcus luteolous, Ustilago maydis, Candida humilis, Pichia onychis, Cadida nitratophila, and Pichia jadinii. The growths of the yeasts were inhibited against each salt concentration. The growths of Candida sp. isolated from the later stage of fermentation was strongly inhibited against 5% concentration of salt. On the other hand the induction phase of Issatchenkia orientalis isolated at the early stage of fermentation was the quickest among all the tested yeasts. Among the salts, bamoo salt was found to be strongest inhibitor of the growth of yeasts.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.231-234
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• 2014

Six unrecorded yeasts, Cryptococcus festucosus 41-3, Cryptococcus heveanensis 56-4, Debaryomyces nepalensis 95-4, Issatchenkia occidentalis 142-1, Dioszegia zsoltii 39-1, and Kwoniella europala 47-2 were screened from 108 yeasts isolated from flowers and fruits in orchards of Yesan-gun, Chungcheongnam-do, Korea. The morphological and cultural characteristics of these unrecorded yeasts were investigated. They had various shapes, including ellipsoidal, globose, and oval, and also had budding mode in vegetable reproduction, except I. occidentalis 142-1 (fission mode). K. europaea 47-2 only formed pseudomycelium. D. zsoliti 39-1 did not grow in yeast extract-malt extract medium, potato dextrose medium, and vitamin-free medium. C. festucosus 41-3 grew well in 5% NaCl-containing yeast extract-peptone-dextrose medium and had a growth pH range of 7.0~10.0. Three unrecorded yeasts Ogataea polymorpha HB45-1, Rhodotonula hinnulla HB62-2, and Cryptococcus rajasthanensis HB80-4 were screened from 51 yeasts isolated from flowers in Hanbat arboretum in Daejeon city, Korea. They were globose in shape and did not form pseudomycelium. In addition, O. polymorpha HB45-1 and C. rajasthanensis HB80-4 had budding mode in vegetable reproduction. All of them grew well in vitamin-free medium and C. rajasthanesis HB80-4 also grew in 50% glucose and 5% NaCl-containing YPD medium.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.201-206
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• 2014

Sixty one yeast strains of 21 species were isolated from wild flowers in Gogunsanyeoldo, including Seonyudo of Jeollabuk-do, Korea, and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Among them, Cryptococcus sp. including C. aureus SY1-4 were found to be dominant, and Metschnikowia sp. including M. reukaufii SY20-1 and Rhodotnula sp. such as R. ingeniosa SY1-1 were also abundantly isolated. Some physiological functionalities of the culture broth and cell-free extracts from 61 yeast strains were determined. Supernatant from Metschnilowia reukaufii SY44-6 showed anti-gout xanthine oxidase inhibitory activity of 49.6% and whitening tyrosinase inhibitory activity of 38.4%, respectively.