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PubMed2005

Anti-inflammatory effect of germanium-concentrated yeast against paw oedema is related to the inhibition of arachidonic acid release and prostaglandin E production in RBL 2H3 cells.

1 To investigate anti-inflammatory activity of organic germanium, we measured the effect of germanium-concentrated yeast on arachidonic acid release, prostaglandin E(2) (PGE(2)) production, histamine release, and intracellular H(2)O(2) or hydroperoxide generation in RBL 2H3 cells, and carrageenan-induced paw oedema in rats. 2 Germanium-concentrated yeast dose-dependently inhibited carrageenan-induced paw oedema, suggesting that germanium-concentrated yeast has anti-inflammatory activity in acute inflammation. 3 Germanium-concentrated yeast significantly inhibited melittin-induced arachidonic acid release and PGE(2) production in RBL 2H3 cells. 4 Germanium-concentrated yeast did not affect melittin-induced histamine release and silica-induced intracellular H(2)O(2) or hydroperoxide generation in RBL 2H3 cells. 5 These results suggest that anti-inflammatory activity of germanium-concentrated yeast appears partly to be related to the inhibition of arachidonic acid release and PGE(2) production in RBL 2H3 cells.

Administration, Oral↗
PubMed2000

Cyanide-resistant respiration is frequent, but confined to yeasts incapable of aerobic fermentation.

In Pichia membranifaciens, cyanide-resistant respiration (CRR) sensitive to salicylhydroxamic acid emerged after forced aeration of starved cells for 4 h. Surveying a large number of species by this simple methodology, we found that CRR is very frequent among yeasts. Remarkably, considering our results together with previous data in the literature, CRR was present in 24 out of 28 non-fermentative or Crabtree-negative yeasts and absent in 10 out of 12 Crabtree-positive yeasts. We submit that, as alternatives to cytochromic respiration, yeasts developed two strategies: either aerobic fermentation in Crabtree-positive yeasts or CRR in non-fermentative or Crabtree-negative yeasts.

Aerobiosis↗
PubMed2000

Carbohydrate and energy-yielding metabolism in non-conventional yeasts.

Sugars are excellent carbon sources for all yeasts. Since a vast amount of information is available on the components of the pathways of sugar utilization in Saccharomyces cerevisiae it has been tacitly assumed that other yeasts use sugars in the same way. However, although the pathways of sugar utilization follow the same theme in all yeasts, important biochemical and genetic variations on it exist. Basically, in most non-conventional yeasts, in contrast to S. cerevisiae, respiration in the presence of oxygen is prominent for the use of sugars. This review provides comparative information on the different steps of the fundamental pathways of sugar utilization in non-conventional yeasts: glycolysis, fermentation, tricarboxylic acid cycle, pentose phosphate pathway and respiration. We consider also gluconeogenesis and, briefly, catabolite repression. We have centered our attention in the genera Kluyveromyces, Candida, Pichia, Yarrowia and Schizosaccharomyces, although occasional reference to other genera is made. The review shows that basic knowledge is missing on many components of these pathways and also that studies on regulation of critical steps are scarce. Information on these points would be important to generate genetically engineered yeast strains for certain industrial uses.

Carbohydrate Metabolism↗
PubMed1983

Quantitative relationship between yeast and bacteria in denture-induced stomatitis.

Quantitative cultural studies of yeasts and bacteria were made from 7-day-old denture plaque accumulate on pieces of self-adhesive tape stuck on the fitting surface of the maxillary denture in 17 edentulous subjects with healthy oral mucosa and in 27 patients affected with denture-induced stomatitis. Significantly higher numbers of yeasts and bacteria were cultured in the stomatitis patients than in the controls. This indicates that the rate of plaque formation is increased in patients with denture-induced stomatitis. Yeasts usually constituted less than 1% of the anaerobic bacterial counts, but the percentage of yeasts was significantly higher in the stomatitis patients than in the controls. There was a significant correlation between initially higher yeast counts and improvement of the clinical condition of the palatal mucosa following antimycotic treatment. In some patients only bacteria were grown and antimycotic treatment had no effect. The study supported the contention that yeast antigens and toxins of denture plaque are significant factors in initiation and maintenance of denture-induced stomatitis. However, bacteria may also be involved as pathogens.

Aged↗
PubMed1993

Biotransformation of polycyclic aromatic hydrocarbons by yeasts isolated from coastal sediments.

Yeast abundance in the sediments of 13 coastal sites in Massachusetts was quantified, and the potential of yeast isolates to biotransform polycyclic aromatic hydrocarbons (PAHs) was determined. Plate counts of yeasts varied between 10(2) to 10(7) CFU g (dry weight) of sediment-1. The most abundant genera isolated and identified included Candida, Cryptococcus, Rhodotorula, Torulopsis, and Trichosporon. More than 50% of the isolates from heavily contaminated sites transformed phenanthrene, as determined by spray-plate screening. The plate counts of phenanthrene-transforming yeasts correlated significantly to the sediment concentrations of phenanthrene. Transformation of [9-14C]phenanthrene and [12-14C]benz[a]anthracene by individual isolates varied greatly, ranging from 0.15 to 8.15 mumol of PAH g-1 in 120-h incubations. Of the isolated yeasts, Trichosporon penicillatum exhibited the greatest capacity for phenanthrene transformation. The ability to transform PAHs appears to be widespread among yeasts in coastal sediments.

Benz(a)Anthracenes↗
PubMed1998

Rapid and reliable identification of food-borne yeasts by Fourier-transform infrared spectroscopy.

Computer-based Fourier-transform infrared spectroscopy (FT-IR) was used to identify food-borne, predominantly fermentative yeasts. Dried yeast suspensions provided the films suitable for FT-IR measurement. Informative windows in the spectrum were selected and combined to achieve optimal results. A reference spectrum library was assembled, based on 332 defined yeast strains from international yeast collections and our own isolates. All strains were identified with conventional methods using physiological and morphological characteristics. In order to assess identification quality, another 722 unknown yeast isolates not included in the reference spectrum library were identified both by classical methods and by comparison of their FT-IR spectra with those of the reference spectrum library. Ninety-seven and one-half percent of these isolates were identified correctly by FT-IR. Easy handling, rapid identification within 24 h when starting from a single colony, and a high differentiation capacity thus render FT-IR technology clearly superior to other routine methods for the identification of yeasts.

Cluster Analysis↗
PubMed2005

Transcriptome analysis of Paracoccidioides brasiliensis cells undergoing mycelium-to-yeast transition.

Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), a systemic mycosis prevalent in South America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and transform into the yeast parasitic form. Thus, the mycelium-to-yeast transition is of particular interest because conversion to yeast is essential for infection. We have used a P. brasiliensis biochip carrying sequences of 4,692 genes from this fungus to monitor gene expression at several time points of the mycelium-to-yeast morphological shift (from 5 to 120 h). The results revealed a total of 2,583 genes that displayed statistically significant modulation in at least one experimental time point. Among the identified gene homologues, some encoded enzymes involved in amino acid catabolism, signal transduction, protein synthesis, cell wall metabolism, genome structure, oxidative stress response, growth control, and development. The expression pattern of 20 genes was independently verified by real-time reverse transcription-PCR, revealing a high degree of correlation between the data obtained with the two methodologies. One gene, encoding 4-hydroxyl-phenyl pyruvate dioxygenase (4-HPPD), was highly overexpressed during the mycelium-to-yeast differentiation, and the use of NTBC [2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione], a specific inhibitor of 4-HPPD activity, as well as that of NTBC derivatives, was able to inhibit growth and differentiation of the pathogenic yeast phase of the fungus in vitro. These data set the stage for further studies involving NTBC and its derivatives as new chemotherapeutic agents against PCM and confirm the potential of array-based approaches to identify new targets for the development of alternative treatments against pathogenic microorganisms.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1965

ENZYMATIC HYDROLYSIS OF YEAST CELL WALLS. I. ISOLATION OF WALL-DECOMPOSING ORGANISMS AND SEPARATION AND PURIFICATION OF LYTIC ENZYMES.

Tanaka, Hirosato (University of California, Davis), and Herman J. Phaff. Enzymatic hydrolysis of yeast cell walls. I. Isolation of wall-decomposing organisms and separation and purification of lytic enzymes. J. Bacteriol. 89:1570-1580. 1965.-A number of microorganisms, able to decompose and grow on yeast cell walls, were isolated from soil. These isolates demonstrated various types of attack on yeast walls. A bacterium, identified as Bacillus circulans, and a species of Streptomyces produced clear, lysed zones when grown on an agar medium containing baker's yeast cell walls. The streptomycete formed glucanase, mannanase, and protease, but B. circulans produced only glucanases. Purified mannan could be prepared from the culture fluid of B. circulans grown on baker's yeast cell walls. In a liquid, mineral medium, extracellular lytic enzyme production by B. circulans was optimal after 3 days of aerobic growth at 30 C with 0.5% baker's yeast cell walls as the carbon source. Twelve other carbon sources were ineffective as inducers. Among a number of polysaccharides tested, the crude enzymes of B. circulans hydrolyzed only beta-1-->3 glucan (laminarin) and beta-1-->6 glucan (pustulan), both by a random mechanism, to a mixture of dimer and glucose. The beta-1-->3 and beta-1-->6 glucanases were separated from each other by diethylaminoethyl cellulose column chromatography. Water-soluble oat glucan, which contains in the linear chain both beta-1-->3 and beta-1-->4 bonds, was also hydrolyzed by the bacterial beta-1-->3 glucanase. The products of this reaction indicated that this enzyme hydrolyzes beta-1-->3 or beta-1-->4 glucosidic linkages, provided the beta-glucopyranosyl units composing these bonds are substituted in the 3 position by another glucose unit.

Bacillus↗
PubMed1981

Detection of yeast septicemia by biphasic and radiometric methods.

From January 1977 to April 1980 our microbiology laboratory used a commercial biphasic brain heart infusion vented culture method for fungal blood cultures and a commercial radiometric (BACTEC 460, Johnson Laboratories, Cockeysville, Md.) method for bacterial blood cultures. A total of 668 biphasic fungal blood cultures were processed, of which 30 grew yeasts from 19 patients. There were 38,324 BACTEC blood cultures processed for bacteria, of which 184 grew yeasts from 85 patients. The overall detection time for all yeasts averaged 8.3 days for the biphasic method and 2.4 days for the radiometric method. The BACTEC aerobic bottle detected over six times as many yeasts as did the anaerobic bottle. Candida albicans was the most frequently isolated yeast in both methods, being detected in an average of 7.7 days in the biphasic method and 1.6 days in the aerobic BACTEC bottle. It is concluded from this study that the radiometric method is far superior to the biphasic method, because (i) it has a shorter detection time, (ii) it can be used simultaneously with bacterial methods, saving blood and money, and (iii) it requires no special or separate media or instructions for yeasts, thus alleviating confusion in the blood collection process.

Aerobiosis↗
PubMed1984

Update and evaluation of the AutoMicrobic yeast identification system.

The AutoMicrobic system (AMS) Yeast Biochemical Card (Vitek Systems Inc., Hazelwood, Mo.) is a system which has been designed for rapid and automated reporting of yeast identification in the clinical laboratory. Recent improvements have been implemented in the AMS data base to expand and enhance its yeast identification capabilities. These improvements include the addition of seven biotypes, changes in data analysis scheme, and construction of the taxonomic keys. The updated system was compared with the API 20C (Analytab Products, Plainview, N.Y.) yeast identification system and a rapid conventional method, using 1,106 clinical and stock yeast isolates. With these improvements, the AMS Yeast Biochemical Card had a correlation of 98.8% with the API 20C system and 93.4% with the rapid conventional method and significantly increased its capability of identifying Cryptococcus neoformans (98%). The most difficult organisms for the system to identify in 22 to 24 h were Cryptococcus terreus (58%) and Cryptococcus uniguttulatus (73%). The updated AMS not only provided more rapid results which were comparable to the other two systems but gave a substantial savings in set-up and reporting time as well.

Microbiological Techniques↗
PubMed1989

Yeast killer toxins and dimorphism.

The differential action of four selected yeast killer toxins on the mycelial and yeast forms of four isolates of the dimorphic fungus Sporothrix schenckii was comparatively evaluated. The results confirmed that the yeast killer phenomenon is present among hyphomycetes and yeasts and that both morphological forms of S. schenckii are susceptible to the action of the same yeast killer toxin. Quantitative differences in the response to the killer action of the mycelial and yeast forms in individual strains were also observed. To avoid retroconversion of the dimorphic forms, we used a modification of the conventional killer system.

Colony Count, Microbial↗
PubMed1991

Evaluation of the Baxter-MicroScan 4-hour enzyme-based yeast identification system.

A new 4-h Yeast Identification Panel (YIP; Baxter-MicroScan, W. Sacramento, Calif.) was compared with the API 20C Yeast Identification System (Analytab Products, Inc., Plainview, N.Y.) in the identification of recent clinical yeast isolates. The YIP had a 94% correlation (288 of 306) in identifying 22 species within the genera Candida, Hansenula, Pichia, Rhodotorula, Saccharomyces, and Torulopsis. Correlation dropped to 65% for those species within the genera of slower growing yeasts, i.e., Blastoschizomyces spp., Crpytococcus spp., Geotrichum spp., Hyphopichia spp., Phaeococcomyces spp., Prototheca spp., and Trichosporon spp. Overall correlation with the API 20C was 92% (365 of 401) for those taxa included in the data base and 85% (373 of 437) for all yeasts encountered in the study. There were 36 (8.2%) discrepant identifications, which were due in part to the limited data base. Expansion of the data base plus the easy inoculation, reading, and rapid results of the YIP should make it an excellent method for yeast identification.

Culture Media↗
PubMed2000

Identification of medically important yeasts using PCR-based detection of DNA sequence polymorphisms in the internal transcribed spacer 2 region of the rRNA genes.

Identification of medically relevant yeasts can be time-consuming and inaccurate with current methods. We evaluated PCR-based detection of sequence polymorphisms in the internal transcribed spacer 2 (ITS2) region of the rRNA genes as a means of fungal identification. Clinical isolates (401), reference strains (6), and type strains (27), representing 34 species of yeasts were examined. The length of PCR-amplified ITS2 region DNA was determined with single-base precision in less than 30 min by using automated capillary electrophoresis. Unique, species-specific PCR products ranging from 237 to 429 bp were obtained from 92% of the clinical isolates. The remaining 8%, divided into groups with ITS2 regions which differed by </=2 bp in mean length, all contained species-specific DNA sequences easily distinguishable by restriction enzyme analysis. These data, and the specificity of length polymorphisms for identifying yeasts, were confirmed by DNA sequence analysis of the ITS2 region from 93 isolates. Phenotypic and ITS2-based identification was concordant for 427 of 434 yeast isolates examined using sequence identity of >/=99%. Seven clinical isolates contained ITS2 sequences that did not agree with their phenotypic identification, and ITS2-based phylogenetic analyses indicate the possibility of new or clinically unusual species in the Rhodotorula and Candida genera. This work establishes an initial database, validated with over 400 clinical isolates, of ITS2 length and sequence polymorphisms for 34 species of yeasts. We conclude that size and restriction analysis of PCR-amplified ITS2 region DNA is a rapid and reliable method to identify clinically significant yeasts, including potentially new or emerging pathogenic species.

DNA, Fungal↗
PubMed2001

Multiplex PCR using internal transcribed spacer 1 and 2 regions for rapid detection and identification of yeast strains.

Multiplex PCR amplification followed by either agarose gel electrophoresis (PCR-AGE) or microchip electrophoresis (PCR-ME) was used to test a total of 120 fungal strains. The internal transcribed spacer 1 (ITS1) and ITS2 regions and the 5.8S ribosomal DNA (rDNA) region of the fungi were amplified by using universal primers ITS1 and ITS4. The ITS2 region was simultaneously amplified by using universal primers ITS3 and ITS4. Since Trichosporon asahi and T. asteroides showed similar lengths for two amplicons, 29 different gel patterns were demonstrated for 30 yeast species tested on the basis of differences in the lengths of one or two amplicons. Of 75 yeast isolates from clinical materials, 5 isolates (6.8%) which were incompletely identified or not identified by the phenotypic method were identified with our PCR-based method (2 isolates as Candida guilliermondii, 2 as C. krusei, and 1 as C. zeylanoides). No differences in discriminating power or sensitivity were observed between the PCR-AGE method and the PCR-ME method. These methods, prospectively applied to 24 yeast-positive blood culture bottles (16 patients), resulted in the correct detection of 24 yeast strains. In conclusion, multiplex PCR followed by electrophoresis seems to be a promising tool for the rapid identification of common and uncommon yeast strains from culture colonies and from yeast-positive blood culture bottles (5.5 h for the PCR-AGE method and 3 h for the PCR-ME method).

DNA, Fungal↗
PubMed2005

Results from the ARTEMIS DISK Global Antifungal Surveillance Study: a 6.5-year analysis of susceptibilities of Candida and other yeast species to fluconazole and voriconazole by standardized disk diffusion testing.

Fluconazole in vitro susceptibility test results for 140,767 yeasts were collected from 127 participating investigators in 39 countries from June 1997 through December 2003. Data were collected on 79,343 yeast isolates tested with voriconazole from 2001 through 2003. All investigators tested clinical yeast isolates by the CLSI (formerly NCCLS) M44-A disk diffusion method. Test plates were automatically read and results were recorded with the BIOMIC Vision Image Analysis System. Species, drug, zone diameter, susceptibility category, and quality control results were collected quarterly via e-mail for analysis. Duplicate (the same patient, same species, and same susceptible-resistant biotype profile during any 7-day period) and uncontrolled test results were not analyzed. The 10 most common species of yeasts all showed less resistance to voriconazole than to fluconazole. Candida krusei showed the largest difference, with over 70% resistance to fluconazole and less than 8% to voriconazole. All species of yeasts tested were more susceptible to voriconazole than to fluconazole, assuming proposed interpretive breakpoints of > or =17 mm (susceptible) and < or =13 mm (resistant) for voriconazole. MICs reported in this study were determined from the zone diameter in millimeters from the continuous agar gradient around each disk, which was calibrated with MICs determined from the standard CLSI M27-A2 broth dilution method by balanced-weight regression analysis. The results from this investigation demonstrate the broad spectrum of the azoles for most of the opportunistic yeast pathogens but also highlight several areas where resistance may be progressing and/or where previously rare species may be "emerging."

Antifungal Agents↗
PubMed1983

Isolation and characterization of sequences from mouse chromosomal DNA with ARS function in yeasts.

Fragments of chromosomal DNA from a variety of eucaryotes can act as ARSs (autonomously replicating sequence) in yeasts. ARSs enable plasmids to be maintained in extrachromosomal form, presumably because they function as initiation sites for DNA replication. We isolated eight different sequences from mouse chromosomal DNA which function as ARSs in Saccharomyces cerevisiae (bakers' yeast). Although the replication efficiency of the different mouse ARSs in yeasts appears to vary widely, about one-half of them functions as well as the yeast chromosomal sequence ARS1. Moreover, five of the ARSs also promote self replication of plasmids in Schizosaccharomyces pombe (fission yeast). Each of the ARSs was cloned into plasmids suitable for transformation of mouse tissue culture cells. Plasmids were introduced into thymidine kinase (TK)-deficient mouse L cells by the calcium phosphate precipitation technique in the absence of carrier DNA. In some experiments, the ARS plasmid contained the herpes simplex virus type 1 TK gene; in other experiments (cotransformations), the TK gene was carried on a separate plasmid used in the same transformation. In contrast to their behavior in yeasts, none of the ARS plasmids displayed a significant increase in transformation frequency in mouse cells compared with control plasmids. Moreover, only 1 of over 100 cell lines contained the original plasmid in extrachromosomal form. The majority of cell lines produced by transformation with an ARS TK plasmid contained multiple copies of plasmid integrated into chromosomal DNA. In most cases, results with plasmids used in cotransformations were similar to those for plasmids carrying TK. However, cell lines produced by cotransformations with plasmids containing any one of three of the ARSs (m24, m25, or m26) often contained extrachromosomal DNAs.

Animals↗
PubMed1977

How often is genital yeast infection sexually transmitted?

We analysed data from a computer-based bank of clinical records of patients seen in a clinic for sexually transmitted diseases over a three-year period to investigate the association between genital yeast infections and sexually transmitted diseases (STDs). We classified STDs as primary and secondary syphilis; gonorrhoea; lymphogranuloma venereum; trichomoniasis; scabies; pediculosis; genital herpes; warts; and molluscum contagiosum. Of a total of 2984 disease episodes among women, 1054 (35-3%) included yeast infections, whereas only 382 (6-9%) of 5501 episodes in heterosexual men were associated with yeast infections, We found a significant association between yeast infection and STD and non-specific genital infection (non-specific urethritis (NSU) and procitis in men, and female contacts of men with NSU), which suggested that yeast infection was sexually acquired in 414 out of 1054 disease episodes in women (39%) and 110 out of 382 episodes in heterosexual men (29%). We conclude that sexually active patients with genital yeast infections should be screened for other STDs particularly non-specific genital infection.

Female↗
PubMed1999

Comparative study of seven commercial yeast identification systems.

AIMS: To compare the performance of seven commercial yeast identification methods with that of a reference method, and to compare the costs of the commercial kits. METHODS: Clinical yeast isolates (n = 52), comprising 19 species, were identified using Vitek, Api ID 32C, Api 20C AUX, Yeast Star, Auxacolor, RapID Yeast Plus system, and Api Candida and compared with a reference method which employed conventional tests. RESULTS: The percentage of correctly identified isolates varied between 59.6% and 80.8%. Overall, the highest performance was obtained with Api Candida (78.8%) and Auxacolor (80.8%). Among germ tube negative yeast isolates, Auxacolor and Api Candida both identified 93.1% of isolates correctly. All systems failed to identify C norvegensis, C catenulata, C haemulonii, and C dubliniensis. In comparison with Auxacolor, the Api Candida is less expensive and requires less bench time. CONCLUSIONS: Auxacolor and Api Candida appeared to be the most useful systems for identification of germ tube negative yeast isolates in clinical microbiology laboratories, although one should be aware that several germ tube negative Candida species cannot be identified by these systems.

Candida↗