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PubMed2006

Candida heliconiae sp. nov., Candida picinguabensis sp. nov. and Candida saopaulonensis sp. nov., three ascomycetous yeasts from Heliconia velloziana (Heliconiaceae).

Strains belonging to three novel yeast species, Candida heliconiae (four isolates), Candida picinguabensis (three isolates) and Candida saopaulonensis (two isolates), were recovered in the year 2000 from water of flower bracts of Heliconia velloziana L. Emigd. (Heliconiaceae) found in a forest ecosystem site in an Atlantic rainforest of south-eastern Brazil. C. picinguabensis and C. saopaulonensis were nearly identical in morphology and physiology, but sequence divergence in the D1/D2 domain of the large-subunit rDNA indicated that they should be regarded as different species. They belong to the Metschnikowiaceae clade. C. heliconiae had affinities to Pichia mexicana and related species, but was genetically isolated from all currently accepted species in that group. The type strains are C. heliconiae UNESP 00-91C1T (=CBS 10000T=NRRL Y-27813T), C. picinguabensis UNESP 00-89T (=CBS 9999T=NRRL Y-27814T) and C. saopaulonensis UNESP 00-99T (=CBS 10001T=NRRL Y-27815T).

Brazil↗
PubMed2006

Molecular-genetic diversity of the ascomycetous yeast genus Arthroascus: Arthroascus babjevae sp. nov., Arthroascus fermentans var. arxii var. nov. and geographical populations of Arthroascus schoenii.

Using molecular and genetic analyses, 28 Arthroascus strains were analysed, isolated from widely different geographical localities in Europe, North America, Far-East Asia and Hawaii. Most of the strains have been assigned to the species Arthroascus schoenii. PCR-RAPD revealed two Japanese Arthroascus strains (UCD 67-278 and IFO 10138) to have peculiar patterns. Comparative rDNA (D1/D2 26S, ITS1 and ITS2) sequence analysis showed that the two strains respectively represent a novel species and a novel variety. Based on the results of sequence analysis, genetic hybridization and DNA-DNA reassociation, two new members of the genus Arthroascus are formally described, Arthroascus babjevae sp. nov. (type strain UCD 67-278(T)=CBS 9167(T)) and Arthroascus fermentans var. arxii var. nov. (type strain IFO 10138(T)=CBS 9168(T)). These results show that A. schoenii has a worldwide distribution, while the species Arthroascus javanensis is represented only by the type culture CBS 2555(T), isolated in Indonesia. Cluster analysis revealed a correlation between PCR-RAPD fingerprints and geographical origin of the A. schoenii strains. Despite this molecular differentiation, A. schoenii strains collected in different regions of the world formed predominantly fertile hybrids, with normal recombination of control markers.

DNA, Fungal↗
PubMed1978

The phenoloxidases of the ascomycete Podospora anserina. Structural differences between laccases of high and low molecular weight.

In order to investigate the extent of the relationship between the three copper-containing glycoproteins, laccases I, II and III (Mr70000, 80000 and 390000 respectively) of Podospora anserina, the following experiments were carried out on laccases II and III: (a) determination of amino acid composition; (b) determination of N-terminal and C-terminal amino acid; (c) determination of sugar composition; (d) dissociation studies on native and denatured laccases and also after removal of copper from the enzymes; (e) digestion of the carbohydrate moieties with the aid of glycosylhydrolases. A comparison between the results of these experiments and data previously obtained with laccase I allows the following conclusions to be drawn. 1. Laccases II and III are not identical. 2. Neither of these low molecular weight laccases are as complete molecules subunits of the oligomeric laccase I. 3. The possibility of partial identity of amino acid sequences of laccases I and III can not be excluded. 4. Laccase II possibly consists of subunits of Mr37000 whereas laccase III does not. 5. Digestion of 50% of the carbohydrate content leads to complete loss of serological specificity (serological reaction and cross reaction). This finding is discussed with regard to the possible role of the carbohydrate moiety as antigenic determinants and thus as the reason for the immunological relationship. As a consequence, at least three independent structural genes for laccases must be assumed.

Amino Acids↗
PubMed2006

The lichen-forming ascomycete Evernia mesomorpha associates with multiple genotypes of Trebouxia jamesii.

The epiphyte Evernia mesomorpha forms a lichen association with green algae in the genus Trebouxia. Little is known about the population structure of E. mesomorpha. Here, population structure of the algal and fungal symbionts was examined for 290 lichen thalli on 29 jack pine (Pinus banksiana) trees in Manitoba. Through phylogenetic analysis of internal transcribed spacer (ITS) nuclear ribosomal DNA (rDNA) sequences, five algal genotypes were detected that were nested within T. jamesii. Two fungal genotypes were detected that formed a clade with two other Evernia species. The genus Evernia was paraphyletic with E. prunastri, sister to Parmelia saxatilis. Restriction fragment length polymorphism (RFLP) of ITS rDNA showed multiple algal genotypes in 45% of the 290 lichen thalli collected, whereas all thalli only contained one fungal genotype. Low population subdivision of algal and fungal genotypes among trees suggested that the algal symbiont was being dispersed in the lichen soredium. Low fungal specificity for multiple algal genotypes and a hypothesized algal switch may be important life history strategies for E. mesomorpha to adapt to changing environmental conditions.

Ascomycota↗
PubMed2001

Six new anamorphic ascomycetous yeasts near Candida tanzawaensis.

Six new species of the yeast genus Candida are described from their unique nucleotide sequences in the D1/D2 domain of 26S rDNA. Five of these species form a clade with Candida tanzawaensis, and the sixth is basal to this group. The new species and their sources of isolation are the following: Candida ambrosiae (type strain NRRL YB-1316, CBS 8844), from insect frass, rotted wood and mushroom fruiting bodies; Candida canberraensis (type strain NRRL YB-2417, CBS 8846), from soil; Candida caryicola (type strain NRRL YB-1499, CBS 8847), from a pignut hickory tree; Candida prunicola (type strain NRRL YB-869, CBS 8848), from exuded gum of a black cherry tree; Candida pyralidae (type strain NRRL Y-27085, CBS 5035), from insect frass; Candida xylopsoci (type strain NRRL Y-27066, CBS 6037), from insect frass.

Animals↗
PubMed2002

Transcription of sterol Delta(5,6)-desaturase and sterol 14alpha-demethylase is induced in the plant pathogenic ascomycete, Leptosphaeria maculans, during treatment with a triazole fungicide.

Two genes whose derived amino acid sequences closely resemble the ergosterol biosynthetic enzymes, sterol Delta(5,6)-desaturase (erg3) and sterol 14alpha-demethylase (erg11), were cloned from the plant pathogenic fungus Leptosphaeria maculans. Transcript levels of both these genes increased following exposure of L. maculans to the triazole fungicide, flutriafol, which specifically inhibits the ergosterol biosynthetic pathway. This induction may be due to a decrease in ergosterol content or to abnormal levels of the ergosterol precursor, 24-methylene dihydrolanosterol.

Amino Acid Sequence↗
PubMed2002

Identification and isolation of two ascomycete fungi from spores of the arbuscular mycorrhizal fungus Scutellospora castanea.

Two filamentous fungi with different phenotypes were isolated from crushed healthy spores or perforated dead spores of the arbuscular mycorrhizal fungus (AMF) Scutellospora castanea. Based on comparative sequence analysis of 5.8S ribosomal DNA and internal transcribed spacer fragments, one isolate, obtained from perforated dead spores only, was assigned to the genus Nectria, and the second, obtained from both healthy and dead spores, was assigned to Leptosphaeria, a genus that also contains pathogens of plants in the Brassicaceae. PCR and randomly amplified polymorphic DNA-PCR analyses, however, did not indicate similarities between pathogens and the isolate. The presence of the two isolates in both healthy spores and perforated dead spores of S. castanea was finally confirmed by transmission electron microscopy by using distinctive characteristics of the isolates and S. castanea. The role of this fungus in S. castanea spores remains unclear, but the results serve as a strong warning that sequences obtained from apparently healthy AMF spores cannot be presumed to be of glomalean origin and that this could present problems for studies on AMF genes.

Ascomycota↗
PubMed1976

Influence of exogenous sugars and polyols on C1-influx and efflux by the ascomycete Neocosmospora vasinfecta.

Glucose and other transportable sugars and polyols inhibited Cl- influx very soon after addition to mycelium in the process of Cl- accumulation. Under the usual experimental conditions (0.1 mM KCl, glucose greater than or equal to 2 mM) the mean percentage of inhibition of Cl- influx by glucose was 54.1 +/- 8.0 (+/- standard error; N = 26). Transport of the exogenous carbohydrate was necessary for inhibition of Cl- influx. Thus, the estimated Ki for glucose inhibition of Cl- influx (28 muM) was close to the Km for glucose transport; glycerol did not inhibit Cl- influx unless it was itself transported, and the degree of inhibition exerted by various carbohydrates correlated with their uptake rates. Inhibition was not caused by the accumulated sugar itself, as high levels (ca. 60 mM) of intramycelial 3-O-methylglucose gave rise to a stimulation of Cl- influx when the exogenous sugar was removed. It is suggested that interaction of Cl- and carbohydrate transport arises from competition for a common energy-coupling mechanism in the cell membrane. Both glucose and 3-O-methylglucose elicited Cl- efflux, but the maximal Cl- efflux rates were observed only after 40 min of incubation and only in the presence of the readily metabolizable glucose. Removal of the exogenous glucose, even after maximal Cl- efflux had been established, resulted in the rapid cessation of efflux. Studies under anaerobic conditions gave further evidence that glucose uptake was necessary and that efflux was not due to temporary depletion of energy reserves. It is proposed that glucose-induced leakage of Cl- is due to reversal of the Cl- uptake system, even though the Km for efflux is much greater than that for influx.

Alcohols↗
PubMed1976

Evidence for a negative membrane potential and for movement of C1- against its electrochemical gradient in the ascomycete Neocosmospora vasinfecta.

The iodides of three lipid-soluble cations (dibenzyldimethylammonium; tribenzylmethylammonium, TBMA+; ethyldimethylbenzylammonium) were synthesized by the reaction of 14C-labeled methyl or 14C-labeled ethyl iodide with the appropriate secondary of tertiary amine and used in an attempt to measure the transmembrane electrical potential difference in Neocosmospora. Only mycelium containing high levels of Na+ accumulated measureable amounts of these cations and only above pH 6. Uptake was reduced in the presence of exogenous K+, Na+, Mg2+, or tris(hydroxymethyl)aminomethane. The velocity of TBMA+ uptake was proportional to its concentration between 46 and 427 muM. Neither the rate nor the extent of TBMB+ uptake was greatly affected by the presence of a fivefold excess of either dibenzyldimethylammonium or ethyldimethylbenzylammonium, even though these cations were themselves accumulated. The uncoupler m-chlorophenylhydrazone induced loss of previously accumulated TBMA+ from the mycelium. Anaerobiosis and cold (5 degrees C) temperature both inhibited TBMA+ uptake but did not induce the loss of previously accumulated TBMA+. The uptake of lipophilic cations by Na+-rich mycelium indicated a minimum transmembrane electrical potential of -60 to -70 mV (inside negative). Net uptake of these cations appeared to be strongly influenced by the availability of endogenous exchangeable cations and by the presence of other exogenous cations, as well as by the membrane potential. Despite these limitations, transport of C1- by Na+-rich mycelium appeared to take place against the electrochemical gradient for C1-.

Anaerobiosis↗
PubMed1995

Fatal cerebral mycoses caused by the ascomycete Chaetomium strumarium.

Three cases of fatal cerebral mycosis in males with prior histories of intravenous drug use from the United States and Australia are reported. Infection in each case was limited to brain abscess; no other sites of infection were observed. The fungus seen by histopathology and isolated from the brain tissue in each case was identified as Chaetomium strumarium. This is the first report of human infection by this species, and C. strumarium is the second species of Chaetomium known to cause primary brain infection. Chaetomium strumarium is unusual among members of the genus Chaetomium in forming ascocarps covered with pale, thin-walled, flexuous hairs, a feature leading to its original placement in the genus Achaetomium. Presence of pinkish exudate droplets and/or crystals associated with hyphae or ascocarps, sometimes accompanied by a pinkish diffusible pigment; good growth at 42 degrees C; and production of small conidia further distinguish this species. The brain abscess isolates were compared with isolates from prior cases of cerebral infection which had been identified as either Chaetomium atrobrunneum or Chaetomium globosum. With reidentification of one isolate originally identified as C. globosum to C. atrobrunneum, only C. strumarium and C. atrobrunneum have been confirmed to cause infection involving the brain.

Adult↗
PubMed1997

Identification of clinically important ascomycetous yeasts based on nucleotide divergence in the 5' end of the large-subunit (26S) ribosomal DNA gene.

Clinically important species of Candida and related organisms were compared for extent of nucleotide divergence in the 5' end of the large-subunit (26S) ribosomal DNA (rDNA) gene. This rDNA region is sufficiently variable to allow reliable separation of all known clinically significant yeast species. Of the 204 described species examined, 21 appeared to be synonyms of previously described organisms. Phylogenetic relationships among the species are presented.

Candida↗
PubMed1998

Degradation of hydrocarbons in crude oil by the ascomycete Pseudallescheria boydii (Microascaceae).

Four unique strains of Pseudallescheria boydii were isolated from oil-soaked soils in British Columbia and Alberta and compared to strains from cattle dung and raw sewage. Considerable variability in morphology, colony appearance, colony diameter, and temperature tolerance occurred among the strains. They also varied in the sporogenous states produced in culture; all strains had a Scedosporium anamorph and either the Graphium anamorph or cleistothecial teleomorph. Conspecificity of the six isolates was inferred from their morphology and supported by restriction fragment length polymorphism profiles of the internally transcribed spacer region of rDNA and comparing these to Petriella sordida, a similar taxon in the Microascaceae. Three of the strains isolated from oil-contaminated soil and the strain from sewage were tested for their ability to utilize hydrocarbons by incubation with Prudhoe Bay Crude oil as the sole carbon source. Gas chromatographic analysis of the residual oil revealed that the strains isolated from oil-contaminated soil degraded the linear aliphatics. The strain from sewage, previously shown by others to utilize the volatile n-alkanes (i.e., ethane, propane, and butane), did not utilize the liquid saturate compounds. None of the strains was observed to degrade compounds in the aromatic fraction. Pseudallescheria boydii may be an important agent for in situ bioremediation of saturates in oil-contaminated sites.

Alberta↗
PubMed1999

Kodamaea kakaduensis and Candida tolerans, two new ascomycetous yeast species from Australian Hibiscus flowers.

Two new yeast species were isolated from flowers of Hibiscus species in Eastern and Northern Australia. Kodamaea kakaduensis is heterothallic, haploid, and similar to other Kodamaea species and to Candida restingae. Buds are often produced on short protuberances, and a true mycelium is formed. The new species differs from others by the assimilation of trehalose, melezitose, and xylitol, and is reproductively isolated. The cells of Candida tolerans are small and a pseudomycelium is formed. The carbon and nitrogen assimilation pattern is reminiscent of that of Zygosaccharomyces rouxii but the two are not closely related. Sequences of the D1/D2 domain of large subunit ribosomal DNA confirm the membership of K. kakaduensis in the genus Kodamaea and indicate that C. tolerans belongs to the Clavispora-Metschnikowia clade, with a moderate relatedness to Candida mogii. The type strains are: K. kakaduensis, UWO(PS)98-119.2 (h+, holotype, CBS 8611) and UWO(PS)98-117.1 (h-, isotype, CBS 8612); and C. tolerans, UWO(PS)98-115.5 (CBS 8613).

Ascomycota↗