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At least 307 records · Page 17Linked to original sources
PubMed2003

Oxylipins and ascospore morphology in the ascomycetous yeast genus Dipodascus.

Immunofluorescence microscopy was used to assess members of the yeast genus Dipodascus for the presence of 3-hydroxy oxylipins. Fluorescence was associated with the aggregating ascospores in all species tested, thus suggesting the association of 3-hydroxy oxylipins with these cells, especially the surrounding slime sheaths. An ultrastructural study of the ascospores revealed sheaths with indentations, probably caused by the close packing of the ascospores to form clusters. In addition, an increase in the neutral and glycolipid fractions as well as a decrease in the phospholipid fraction during ascosporogenesis in D. ambrosiae was found.

Fatty Acids, Unsaturated↗
PubMed2004

Variation in functional ascospore parts in the ascomycetous yeast Dipodascopsis uninucleata.

A variation in functional ascospore morphology was detected using electron microscopy (EM) in two varieties of the yeast Dipodascopsis uninucleata, i.e., D. uninucleata var. uninucleata and D. uninucleata var. wickerhamii. It was found that the latter produces ascospores characterized by the absence of small surface hooks which have been implicated in the release and re-assembly of ascospores in D. uninucleata var. uninucleata. These varieties are closely related on the basis of their mode of sexual reproduction, ascospore morphology as observed under the light microscope, physiological characteristics as well as the extent of divergence in the variable D1/D2 domain of the large subunit 26S ribosomal DNA.

Phenotype↗
PubMed2006

Hypocrellin D, a cytotoxic fungal pigment from fruiting bodies of the ascomycete Shiraia bambusicola.

A fungal pigment, hypocrellin D (1), together with three known perylenequinone derivatives hypocrellin A (2), B (3) and C (4), was isolated from the fruiting bodies of Shiraia bambusicola. Its structure was elucidated on the basis of spectral data including 2D NMR experiments. Hypocrellin D (1) significantly inhibited the growth of tumor cell lines Bel-7721, A-549 and Anip-973 with IC50 values of 1.8, 8.8, 38.4 microg/ml, respectively.

Antibiotics, Antineoplastic↗
PubMed2006

The dasyscyphins A-C and niveulone, new biologically active compounds from the ascomycete Dasyscyphus niveus.

In the course of a screening for cytotoxic compounds from fungi four new terpenoid metabolites, named dasyscyphins A, B, C, and niveulone were isolated from fermentations of Dasyscyphus niveus strain A0101. While dasyscyphin A (1) exhibited no significant biological activities in our test systems dasyscyphin B (2) and dasyscyphin C (3) showed cytotoxic activities against human (HepG2, Hela S3, U937, Colo-320, Jurkat) cell lines with IC50-values of 0.5-3 microg/ml while the activity of niveulone (4) was less pronounced. Only modest or weak antibiotic properties were observed for (2) and (3).

Anti-Bacterial Agents↗
PubMed1998

Integrity of a Zn finger-like domain in SamB is crucial for morphogenesis in ascomycetous fungi.

Genetic features determine the site of polarized growth in filamentous fungi and lead to hyphal tip extension or subapical branching. We have isolated the samB gene (suppressor of anucleate metulae) of Aspergillus nidulans which encodes a 66 kDa protein carrying an atypical Cys4 and an additional Cys2/His/Cys Zn finger motif at the carboxy-terminus. Such novel Zn finger-like domains have recently been found in several other developmental regulators in organisms ranging from yeast to man. Deletion of this domain at the carboxy-terminus of SamB led to premature hyphal ramification, mislocalization of septa and suppression of the asporogenous phenotype of the developmental mutant aps (anucleate primary sterigmata). A DeltasamB deletion strain displayed an identical phenotype. A homologous gene in Saccharomyces cerevisiae was also characterized whose deletion resulted in a multi-budding phenotype; thus it was named MUB1. An underlying common mechanism for both genes in determination of the onset of polarized growth and its links to other cellular developmental processes is discussed.

Amino Acid Sequence↗
PubMed1996

Inheritance of mitochondrial DNA and plasmids in the ascomycetous fungus, Epichloë typhina.

We analyzed the inheritance of mitochondrial DNA (mtDNA) species in matings of the grass symbiont Epichloë typhina. Eighty progeny were analyzed from a cross in which the maternal (stromal) parent possessed three linear plasmids, designated Callan-a (7.5 kb), Aubonne-a (2.1 kb) and Bergell (2.0 kb), and the paternal parent had one plasmid, Aubonne-b (2.1 kb). Maternal transmission of all plasmids was observed in 76 progeny; two progeny possessed Bergell and Callan-a, but had the maternal Aubonne-a replaced with the related paternal plasmid Aubonne-b; two progeny lacked Callan-a, but had the other two maternal plasmids. A total of 34 progeny were analyzed from four other matings, including a reciprocal pair, and in each progeny the plasmid transmission was maternal. The inheritance of mitochondrial genomes in all progeny was analyzed by profiles of restriction endonuclease-cleaved mtDNA. In most progeny the profiles closely resembled those of the maternal parents, but some progeny had nonparental mtDNA profiles that suggested recombination of mitochondrial genomes. These results indicate that the fertilized stroma of E. typhina is initially heteroplasmic, permitting parental mitochondria to fuse and their genomes to recombine.

Ascomycota↗
PubMed2001

Cell polarity and hyphal morphogenesis are controlled by multiple rho-protein modules in the filamentous ascomycete Ashbya gossypii.

Polarized cell growth requires a polarized organization of the actin cytoskeleton. Small GTP-binding proteins of the Rho-family have been shown to be involved in the regulation of actin polarization as well as other processes. Hyphal growth in filamentous fungi represents an ideal model to investigate mechanisms involved in generating cell polarity and establishing polarized cell growth. Since a potential role of Rho-proteins has not been studied so far in filamentous fungi we isolated and characterized the Ashbya gossypii homologs of the Saccharomyces cerevisiae CDC42, CDC24, RHO1, and RHO3 genes. The AgCDC42 and AgCDC24 genes can both complement conditional mutations in the S. cerevisiae CDC42 and CDC24 genes and both proteins are required for the establishment of actin polarization in A. gossypii germ cells. Agrho1 mutants show a cell lysis phenotype. Null mutant strains of Agrho3 show periodic swelling of hyphal tips that is overcome by repolarization and polar hyphal growth in a manner resembling the germination pattern of spores. Thus different Rho-protein modules are required for distinct steps during polarized hyphal growth of A. gossypii.

Actins↗
PubMed1996

Loculoascomycete origins and evolution of filamentous ascomycete morphology based on 18S rRNA gene sequence data.

The fungal subclass Loculoascomycetes is characterized by asci or sexual spore sacks with two separable wall layers. At maturity, the inner wall layer protrudes out beyond the outer wall as in a jack-in-the-box. If the Loculoascomycetes were monophyletic and their jack-in-the-box type asci evolved once, then taxa from diverse loculoascomycete lineages would cluster together in a DNA sequence-based tree. To evaluate the phylogenetic history of the two-walled asci, I sequenced the 18S nuclear rRNA genes of 16 species from seven families in the loculoascomycete orders Pleosporales, Dothideales, and Chaetothyriales. Within the Loculoascomycetes, the Pleosporales form a monophyletic group in 99% of the bootstrapped parsimony trees. The Dothideales usually appear as a monophyletic group but without statistical support. Capronia pilosella (Herpotrichiellaceae, Order Chaetothyriales) clusters with plectomycete members of the subclass Euascomycetes rather than the other Loculoascomycetes in 99% of parsimony and neighbor-joining bootstrap replicates. Although the jack-in-the-box-type ascus is a good marker for large, monophyletic loculoascomycete orders, it must have evolved at least twice or been lost at least once.

Ascomycota↗
PubMed1999

Phylogenetic relationships among ascomycetes: evidence from an RNA polymerse II subunit.

In an effort to establish a suitable alternative to the widely used 18S rRNA system for molecular systematics of fungi, we examined the nuclear gene RPB2, encoding the second largest subunit of RNA polymerase II. Because RPB2 is a single-copy gene of large size with a modest rate of evolutionary change, it provides good phylogenetic resolution of Ascomycota. While the RPB2 and 18S rDNA phylogenies were highly congruent, the RPB2 phylogeny did result in much higher bootstrap support for all the deeper branches within the orders and for several branches between orders of the Ascomycota. There are several strongly supported phylogenetic conclusions. The Ascomycota is composed of three major lineages: Archiascomycetes, Saccharomycetales, and Euascomycetes. Within the Euascomycetes, plectomycetes, and pyrenomycetes are monophyletic groups, and the Pleosporales and Dothideales are distinct sister groups within the Loculoascomycetes. We confirm the placement of Neolecta within the Archiascomycetes, suggesting that fruiting body formation and forcible discharge of ascospores were characters gained early in the evolution of the Ascomycota. These findings show that a slowly evolving protein-coding gene such as RPB2 is useful for diagnosing phylogenetic relationships among fungi.

Ascomycota↗
PubMed2000

Terminal-sequence conservation identifies spliceosomal introns in ascomycete 18S RNA genes.

Twenty-four new insertions were obtained from seven different locations in the nuclear 18S rDNA for seven species of the lichen-forming fungal genus PHYSCONIA: They were analyzed allowing for terminal sequence conservation by adopting a flexible approach to exact insertion site position, and they were compared with 12 previously reported small insertion sequences from the 18S ribosomal RNA gene. Such insertions have previously been proposed to be degenerate self-splicing group I introns; however, the methodology used here identified consensus terminal sequences characteristic of spliceosomal introns. This finding is the first suggestion that multiple spliceosomal introns occur in ribosomal genes.

Ascomycota↗
PubMed2003

Starmerella meliponinorum sp. nov., a novel ascomycetous yeast species associated with stingless bees.

Thirty-two strains of the novel species Starmerella meliponinorum sp. nov. were isolated from various substrates associated with three stingless bee species (tribe Meliponini) in Brazil and one in Costa Rica. The strains were found in garbage pellets (faecal material, discarded pollen or food, etc.), pollen provisions, adult bees, honey and propolis of Tetragonisca angustula, in honey from Melipona quadritasciata and in adults of Melipona rufiventris and Trigona fulviventris. The sequence of the D1/D2 domains of the large-subunit rDNA showed that the novel species belongs to the Starmerella clade and is most closely related to Candida etchellsii, although the two differ in their sequences by 7% base substitutions. S. meliponinorum is homothallic and assimilates few carbon sources. Nitrate is utilized as a sole nitrogen source. The type strain of S. meliponinorum is strain UFMG-01-J26.1T (=CBS 9117T).

Animals↗
PubMed2004

Kazachstania aerobia sp. nov., an ascomycetous yeast species from aerobically deteriorating corn silage.

In an investigation of the yeast biota involved in silage deterioration, a considerable number of strains belonging to Saccharomyces and related genera were isolated from aerobically deteriorating corn silage in Tochigi, Japan. Analysis of sequences of the internal transcribed spacer and the large-subunit rRNA gene D1/D2 domain and electrophoretic karyotyping indicated that two of the strains, NS 14(T) and NS 26, represent a novel species with close phylogenetic relationships to Kazachstania servazzii and Kazachstania unispora. It is proposed that the novel species be named Kazachstania aerobia sp. nov., with NS 14(T) (=AS 2.2384(T)=CBS 9918(T)) as the type strain.

DNA, Fungal↗
PubMed2004

Candida leandrae sp. nov., an asexual ascomycetous yeast species isolated from tropical plants.

The novel yeast species Candida leandrae is described based on eight isolates from decaying fruits of Leandra reversa Cogn. (Melastomataceae) in an Atlantic rainforest site in Brazil, one from a Convolvulaceae flower in Costa Rica and one from a drosophilid in Hawai'i. The strains differed in their colony morphology, one being butyrous and smooth and the other being filamentous and rugose. Sequences of the D1/D2 domains of the large-subunit rRNA gene from both morphotypes were identical. C. leandrae belongs to the Kodamaea clade and is closely related to Candida restingae. The two species can be separated on the basis of growth at 37 degrees C and the assimilation of melezitose, negative in the novel species. The type culture of C. leandrae is strain UNESP 00-64R(T) (=CBS 9735(T)=NRRL Y-27757(T)).

Brazil↗
PubMed2005

Taxonomy and phylogeny of the ascomycetous yeast genus Zygoascus, with proposal of Zygoascus meyerae sp. nov. and related anamorphic varieties.

Physiological characters, mating compatibility, PCR-RAPD fingerprints, mol% G + C content, DNA-DNA relatedness, and large-subunit and internal transcribed spacer rRNA gene sequences of strains assigned to the genus Zygoascus were re-examined. On the basis of those data, and after phylogenetic analyses, an emendation of Zygoascus hellenicus (type material is a cross of CBS 6736(T) x CBS 5839(T)) is proposed, comprising two novel anamorphic varieties, Candida steatolytica var. steatolytica (CBS 6736(T)) and C. steatolytica var. inositophila (CBS 5839(T)). A novel teleomorphic species, Zygoascus meyerae sp. nov. (type material is a cross of CBS 4099(T) x CBS 7521(T)) is described, together with two novel anamorphic varieties corresponding to it, Candida hellenica var. hellenica (CBS 4099(T)) and C. hellenica var. acidophila (CBS 7115(T)).

Base Composition↗