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At least 91 records · Page 5Linked to original sources

PubMed1995

Evidence for giant linear plasmids in the ascomycete Podospora anserina.

In the extrachromosomal mutant AL2 of the ascomycete Podospora anserina longevity is correlated with the presence of the linear mitochondrial plasmid pAL2-1. In addition to this autonomous genetic element, two types of closely related pAL2-1-homologous molecules were detected in the high-molecular-weight mitochondrial DNA (mtDNA). One of these molecules is of linear and the other of circular structure. Both molecules contain pAL2-1 sequences which appear to be integrated at the same site in the mtDNA. Sequence analysis of a DNA fragment cloned from one of these molecules revealed that it contains an almost full-length copy of pAL2-1. At the site of plasmid integration a 15-nucleotide AT-spacer and long inverted mtDNA sequences were identified. Finally, two giant linear plasmid-like DNAs of about 50 kbp and 70 kbp were detected in pulsed-field gels of mutant AL2. These molecules are composed of mtDNA and pAL2-1-specific sequences and may result from the integration of mtDNA sequences into linear plasmid pAL2-1.

Base Sequence↗

PubMed1978

Torulopsis geochares and Torulopsis azyma, two new, haploid species of ascomycetous affinity.

There strains representative of two undescribed Torulopsis species, T. geochares and T. azyma, were recovered from soil and rupicolous lichen in South Africa. Descriptions of the new species are given. Ploidy determinations by X-ray inactivation showed the type strains of the two new species to be haploid. On the basis of their affinitive characteristics the new species appear to be related to the ascomycetous yeasts.

Candida↗

PubMed1988

The effect of growth conditions on production and excretion of extracellular antigens by three ascomycetous yeasts.

Ascomycetous yeasts produce extracellular antigens that are almost specific for the species. The antigen production by Hansenula wickerhamii and Stephanoascus ciferrii was independent of the carbon source and was proportional to the final cell density of the cultures. The same was true of chemostat cultures of Stephanoascus ciferrii, irrespective of the dilution rate and whether glucose or ammonia was the limiting nutrient. In cultures of Saccharomyces cerevisiae, however, antigen excretion mainly took place in the late exponential growth phase. Large amounts of antigen were extracted from the cell wall of Saccharomyces cerevisiae. A small amount was detected in the cytoplasm.

Ammonia↗

PubMed1989

Coenzyme Q systems in ascomycetous black yeasts.

72 Strains belonging to 44 species of ascomycetous black yeasts were analyzed for their coenzyme Q systems. Prevalent were Q-10 and dihydrogenated Q-10 systems. Members of the Dothidealean suborder Dothideineae have Q-10(H2), while those belonging to the suborder Pseudosphaeriineae mostly have Q-10. The anamorph genus Exophiala Carmichael and the teleomorph genus Capronia Sacc. seem to be heterogeneous.

Animals↗

PubMed1992

Degradation of some phenols and hydroxybenzoates by the imperfect ascomycetous yeasts Candida parapsilosis and Arxula adeninivorans: evidence for an operative gentisate pathway.

The imperfect ascomycetous yeasts Candida parapsilosis and Arxula adeninivorans degraded 3-hydroxybenzoic acid via gentisate which was the cleavage substrate. 4-Hydroxybenzoic acid was metabolized via protocatechuate. No cleavage enzyme for the latter was detected. In stead of this NADH- and NADPH-dependent monooxygenases were present. In cells grown at the expense of hydroquinone and 4-hydroxybenzoic acid, enzymes of the hydroxyhydroquinone variant of the 3-oxoadipate pathway were demonstrated, which also took part in the degradation of 2,4-dihydroxybenzoic acid by C. parapsilosis.

Biodegradation, Environmental↗

PubMed1993

Systematics of the ascomycetous yeasts assessed from ribosomal RNA sequence divergence.

Extent of divergence in partial nucleotide sequences from large and small subunit ribosomal RNAs was used to estimate genetic relationships among ascomycetous yeasts and yeastlike fungi. The comparisons showed four phylogenetically distinct groups comprised of the following taxa: Group 1. The budding yeasts Saccharomyces, Saccharomycopsis, Debaryomyces, Metschnikowia, Saturnospora, and Lipomyces, and the yeastlike genera Ascoidea, Cephaloascus, Dipodascus, Dipodascopsis, and Galactomyces; Group 2. Eremascus, Emericella and Ceratocystis; Group 3. Taphrina and Protomyces; Group 4. Schizosaccharomyces. Because of the genetic relationships indicated by sequence analysis, Group 1 taxa are retained in the order Endomycetales, and Schizosaccharomyces is retained in the Schizosaccharomycetales Prillinger et al. ex Kurtzman.

Ascomycota↗

PubMed1977

Determination of the absolute configuration at C-20 and C-24 of ergosterol in Ascomycetes and Basidiomycetes by proton magnetic resonance spectroscopy.

Samples of ergosterol isolated from Saccharomyces cerevisiae, Neurospora crassa, and Agaricus sp., and commercial ergosterol all displayed identical proton magnetic resonance (PMR) spectra at 220 MHz. From the effects produced on the doublet for C-21 by epimerization at C-20 and C-24 in sterols of known configuration, the absolute configurations at these positions in ergosterol were determined. The data demonstrate that ergosterol from both Ascomycetes and Basidiomycetes is the same and that at C-20 and C-24, the two H-atoms are on the alpha-side of the asymmetric carbon atoms and that C-22 is trans-oriented with respect to C-13 about the 17(20)-bond.

Ascomycota↗

PubMed1992

Purification and characterization of a xylanase from the thermophilic ascomycete Thelavia terrestris 255B.

Thielavia terrestris 255B, a thermophilic ascomycete, produced two major forms of xylanase with pIs of 4.6 (xylanase I) and 6.1 (xylanase II). The latter enzyme could be purified to greater than 99% homogeneity using anion-exchange chromatography and gel filtration. Xylanase II had a mol wt of 25.7 kDa (SDS-PAGE) and a pH and a temperature optimum of 3.6-4.0 and 60-65 degrees C, respectively. The ratio of the enzyme's activity against xylan and carboxymethylcellulose was 500-1000 to 1, indicating a possible application of this enzyme in biobleaching processes. The amino acid sequence of this protein is being determined, and initial data suggest that the enzyme belongs to a group of low-mol wt xylanases that have been isolated from both bacteria and fungi.

Amino Acid Sequence↗

PubMed2003

Infections with the ascomycete fungus Metschnikowia typographi sp.nov. in the bark beetles Ips typographus and Ips amitinus (Coleoptera, Scolytidae).

The ascomycete fungus Metschnikowia typographi sp.nov. is described. It infects the spruce bark beetles Ips typographus L. and Ips amitinus Eichl. Masses of vegetative cells and navicular asci (I. typographus 13-17 x 2 microns; I. amitinus 17-22 x 2 microns) were found in cells of the midgut epithelium and in the body cavity of infected beetles. Each ascus contains two needle-shaped ascospores flattened in the central part, 0.5-1.5 x 0.3 x 13-15 microns and pointed at both ends. The parasitic species of Metschnikowia, M. bicuspidata, M. artemiae, M. unicuspidata, M. wickerhami and M. typographi are discussed as a special group of the genus characterized by morphological characters.

Animals↗

PubMed1999

A Group I intron in the nuclear small subunit rRNA gene of Cryptendoxyla hypophloia, an ascomycetous fungus: evidence for a new major class of Group I introns.

The ascomycetous fungus Cryptendoxyla hypophloia contains an insertion of 433 base pairs in the genes encoding nuclear small subunit ribosomal RNA. Secondary structure analyses of the insert reveal characteristics indicative of a Group I intron, including elements P, Q, R, and S; however, the sequences of these conserved regions deviate significantly from recognized consensus sequences for Group I introns. Principal-components analysis, based on 79 nucleotide positions from the conserved core sequences of 93 Group I introns, identified 17 introns similar to that of C. hypophloia. This grouping, which includes inserts from phylogenetically diverse organisms, cannot readily be classified in any previously recognized major group of Group I introns. We propose the creation of a new group, IE, to accommodate these sequences, and discuss the evolutionary relationships between group IE and other major groups of Group I introns.

Ascomycota↗

PubMed2002

Purification and characterisation of a novel laccase from the ascomycete Melanocarpus albomyces.

A novel laccase from the ascomycete Melanocarpus albomyces was purified and characterised. The enzyme was purified using anion exchange chromatography, hydrophobic interaction chromatography and gel filtration, and the purified laccase was biochemically characterised. It had activity towards typical substrates of laccases including 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate), dimethoxyphenol, guaiacol, and syringaldazine. The laccase showed good thermostability and it had a pH optimum at neutral pH, both unusual properties for most known fungal laccases. The activity of the laccase from M. albomyces was highest at 60-70 degrees C. With guaiacol and syringaldazine the pH optima were rather broad: 5-7.5 and 6-7, respectively. It retained 50% of its activity after 5 h incubation at 60 degrees C. The molecular weight of the laccase was about 80 kDa and the isoelectric point 4.0. The ultraviolet-visible absorption and electron paramagnetic resonance spectra of the purified laccase indicated that the typical three types of copper were present.

Amino Acid Sequence↗

PubMed2004

Small, basic antifungal proteins secreted from filamentous ascomycetes: a comparative study regarding expression, structure, function and potential application.

Peptides and proteins with antimicrobial activity are produced throughout all kingdoms in nature, from prokaryotes to lower and higher eukaryotes, including fungi, plants, invertebrates and vertebrates. These proteins contribute to an important constitutive or induced defense mechanism of the producer against microorganisms. According to their variety in structure and function, these proteins are classified arbitrarily into groups that are based on their mechanism of action, their structure and their similarity to other known proteins. The present review focuses on a new group of antimicrobial proteins, namely small, basic and cysteine-rich antifungal proteins, which are secreted from filamentous fungi of the group Ascomycetes. These proteins are encoded by orthologous genes and exhibit both similarities and differences concerning their species-specificity, primary structure, protein activity and target sites. The properties of these proteins, their possible mode of action and their potential application for human benefits are discussed in comparison with other already well known antimicrobial proteins.

Antifungal Agents↗

PubMed2004

Bioconversion of (+)-valencene in submerged cultures of the ascomycete Chaetomium globosum.

Submerged cultures of the ascomycete Chaetomium globosum oxidised the exogenous sesquiterpene (+)-valencene to nootkatone via the stereoselective generation of alpha-nootkatol. Inhibition experiments suggested that the first introduction of oxygen, the rate-limiting step of the bioconversion, may have been catalysed by a cytochrome-P450-monooxygenase. However, nootkatone was not the final metabolite: further flavour-active and inactive, non-volatile oxidation products were identified. (+)-Valencene and the flavour-active mono-oxyfunctionalised transformation products, alpha-nootkatol, nootkatone, and valencene-11,12-epoxide accumulated preferably inside the fungal cells. Di- and poly-oxygenated products, such as nootkatone-11,12-epoxide, were found solely in the culture medium, indicating an active transport of these metabolites into the extracellular compartment during (+)-valencene detoxification. These metabolic properties may have contributed to the high tolerance of the fungus towards the exogenous hydrocarbon.

Biotechnology↗

PubMed2005

Mineralization of 14C-labelled synthetic lignin and extracellular enzyme activities of the wood-colonizing ascomycetes Xylaria hypoxylon and Xylaria polymorpha.

Two wood-dwelling ascomycetes, Xylaria hypoxylon and Xylaria polymorpha, were isolated from rotting beech wood. Lignin degradation was studied following the mineralization of a synthetic [formula: see text]-labelled lignin in solid and liquid media. Approximately 9% of the synthetic lignin was mineralized by X. polymorpha during the growth on beech wood meal, and the major fraction (65.5%) was polymerized into water- and dioxan-insoluble material. Both fungi produced laccase (up to 1,200 U l-1) in an agitated complex medium based on tomato juice; peroxidase activity (<80 U l-1) was only detected for X. polymorpha in soybean meal suspension. The enzymatic attack of X. polymorpha on beech wood resulted in the formation of three fractions of water-soluble lignocellulose fragments with molecular masses of 200, 30 (major fraction) and 3 kDa, as demonstrated by high-performance size exclusion chromatography. This fragment pattern differs considerably from that of the white-rot fungus Bjerkandera adusta, which preferentially released smaller lignocellulose fragments (0.8 kDa). The finding that X. polymorpha produced large lignocellulose fragments, along with the fact that high levels of hydrolytic enzymes (esterase 630 U l-1, xylanase 120 U l-1) were detected, indicates the cleavage of bonds between the lignin and hemicellulose moieties.

Biopolymers↗

PubMed1999

Modulation of gene expression by (CA)n microsatellites in the filamentous ascomycete Podospora anserina.

A microsatellite consisting of the alternating pyrimidine-purine sequence (CA)n. (TG)n is found to occur in very conserved form in the genome of various races of the filamentous ascomycete Podospora anserina. Screening of a cDNA library revealed that this sequence is frequently transcribed. In this study, we focused our attention on a short (CA)5 microsatellite located in the 5' untranslated sequence of the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of P. anserina. Specifically, we investigated whether or not the number of repeat units present in the microsatellite affects the expression of the beta-D-glucuronidase (gusA) reporter gene introduced on an autonomously replicating plasmid into fungal protoplasts. The results show that an increase in the number of microsatellite repeat units positively affects reporter gene expression.

DNA, Complementary↗

PubMed2003

Characterisation of the mating-type locus of the plant pathogenic ascomycete Leptosphaeria maculans.

The nucleotide sequences of regions containing the mating-type locus of the plant-pathogenic ascomycete Leptosphaeria maculans are described. The MAT1-1 gene is 1,368 bp, encoding a predicted protein of 441 amino acids, with a 45-bp intron. The MAT1-2 gene is 1,246 bp, encoding a predicted protein of 397 amino acids, with a 55-bp intron. This latter gene is 334 bp downstream of a small open reading frame (32 amino acids) with four amino acids in identical positions to those in the high mobility group binding domain of the MAT1-2 genes. The DNA lyase and anaphase promoting complex genes are 3' of the MAT gene, whilst a gene denoted ORF1 in Cochliobolus heterostrophus and the GTPase activating protein are present 5' of MAT. The transcriptional patterns of genes within and flanking the L. maculans MAT locus are determined. The MAT transcripts are about twice the length of the gene. The ORF1 transcript is 1.2 kb in the MAT1-1 isolate and 1.0 kb in the MAT1-2 isolate; and probes cross-hybridise weakly. A mating-type PCR assay with three nucleotide primers is developed for L. maculans.

Amino Acid Sequence↗

PubMed2003

A putative mitochondrial fission gene from the ectomycorrhizal ascomycete Tuber borchii Vittad.: cloning, characterisation and phylogeny.

Mitochondrial binary division is a complex process occurring in multiple steps, mediated by several proteins. In Saccharomyces cerevisiae, a mitochondrial membrane protein, Fis1p, is required for the proper assembly of the mitochondrial division apparatus. In this study, we report the cloning, characterisation and phylogenetic analysis of Tbfis1, a gene from the ectomycorrhizal ascomycetous truffle Tuber borchii, encoding for an orthologue of S. cerevisiae Fis1p. The Tbfis1 coding region consists of a 468-nucleotide open reading frame interrupted by four introns, which encodes for a polypeptide of 155 amino acids, having a predicted transmembrane domain structure typical of the Fis1p Family. Southern blot analysis revealed that Tbfis1 is a single-copy gene in the T. borchii genome. Tbfis1 is highly expressed during the first stages of T. borchii fruit body ripening, while its expression decreases during T. borchii mycelium ageing. Also, Virtual Northern blot analysis revealed Tbfis1 expression in the symbiotic phase of the fungus life cycle. Phylogenetic analysis allowed the identification of Tbfis1 orthologues in filamentous fungi, yeasts, plants, worms, flies and mammals, indicating that the function of the protein coded by this gene has been conserved during evolution.

Amino Acid Sequence↗

PubMed2005

Initial molecular characterization of a novel Rho-type GTPase RhoH in the filamentous ascomycete Ashbya gossypii.

The organization of the actin cytoskeleton is of central importance in determining cell shape and morphogenesis. Rho-type GTP-binding proteins are known for their role to activate downstream effector proteins that act as scaffolds and direct the assembly of actin filaments. We have identified a novel Rho-type GTPase, RHOH, in the filamentous ascomycete Ashbya gossypii and also in one of its closest relatives, Holleya sinecauda both species belonging to the genus Eremothecium. RHOH is a paralog of AgRHO1 and was generated by tandem duplication in an evolutionary ancestor but is not found in Saccharomyces cerevisae. Deletion of RHOH was carried out in both A. gossypii and H. sinecauda and showed that this gene is non-essential. However, a cell wall defect was observed that led to increased cell lysis at the hyphal tip and an increased sensitivity against the cell wall agents calcofluor and SDS in the AgrhoH strain. These results suggested at least partially overlapping functions between RhoH and Rho1 without excluding any spilt functions of these proteins. Deletion of both the RHOH and RHO1 genes in A. gossypii exacerbated the mutant rho1 phenotype and resulted in germination deficient spores. This suggests that Rho1/RhoH -in contrast to Cdc42- are required at the early steps of spore germination.

Amino Acid Sequence↗