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PubMed2004

The type species of Verticillium is not congeneric with the plant-pathogenic species placed in Verticillium and it is not the anamorph of 'Nectria' inventa.

The monotype species of the genus Verticillium, Verticillium tenerum, is a synonym of the older name Sporotrichum luteo-album. Its purported teleomorph connection with 'Nectria' inventa is refuted and the preserved specimens of that species are considered as probably identical with Stephanonectria keithii (Bionectriaceae). V. luteo-album takes a unique position in the Glomerella clade of ascomycetes, as sister of the Verticillium-Plectosphaerella clade, which comprises plant-pathogenic species. V. luteo-album is not closely related to V. dahliae and its relatives, which are also situated in this clade. Conservation of the name Verticillium with V. dahliae as conserved type will be necessary to retain this generic name for the plant-pathogenic Verticillium species. In anticipation of this conservation, the new combination Acrostalagmus luteo-albus (syn. Sporotrichum luteo-album) is made.

DNA, Fungal↗
PubMed2005

Diagnostic characters of propagules of Ingoldian fungi.

This first contribution of a planned series on the morphology of the Ingoldian fungi discusses three aspects useful for conidial identification, something needed principally in stream ecology and biodiversity surveys: (1) types of propagules found; (2) release organ remnants found on propagules; and (3) conidial tails (or caudal appendages). (1) Propagules can be unexpectedly varied, and difficulty may be encountered in distinguishing, for example, misshapen conidia from expected ranges in conidial form, or in recognizing the outcome of post-release morphogenesis (involving elongation, branching or fragmentation, the latter resulting in part-conidia of several kinds); autonomous hyphal branching systems resembling branched conidia may undergo disorganized in situ fragmentation; propagules may be compound, the components covering more than one generation of the same morph or even more than one morph; conidial aggregations may behave as single dispersal units; and in one case it may be difficult to distinguish between thalli and propagules. (2) Conidia secede by means of various specialized structures (release organs) which leave behind remnants of diagnostic value. Among ascomycetous anamorphs are scars (half-septa resulting from schizolysis of release septa), basal collars (portions of lateral walls resulting from rhexolysis or fracture of release or separation cells), and in one case mucilaginous masses (probably the result of the gelification of release cells). The location of scars can sometimes only be inferred by means of other diagnostic characters, and in some instances it cannot even be inferred. This may lead to problems in orientating conidial and consequently in their identification. In the case of release cells, the remnants on the conidium frequently disappear or become indistinct. Among basidiomycetous anamorphs are twin scars (the result of paired schizolysis of the two septa, i.e. the axial and bridge septa, in the release clamp), excentric collars (seemingly the result of a combination of schizo- and rhexolysis of clamp components) and basal collars (the outcome of lysed evacuate conidiogenous cells). (3) The presence of tails is often inconstant, but where recognizable three types occur which may significantly aid in conidial orientation and hence identification. In addition, three methodological aspects are emphasized: the effect of the position of the conidium on the appreciation of some diagnostic characters, the need to observe spent conidiogenous structures, and in some cases the necessity of directly observing morphogenesis in order to interpret the conidial form.

Ascomycota↗
PubMed2000

Phylogenetic-comparative analysis of the eukaryal ribonuclease P RNA.

Ribonuclease P (RNase P) is the ribonucleoprotein enzyme that cleaves 5'-leader sequences from precursor-tRNAs. Bacterial and eukaryal RNase P RNAs differ fundamentally in that the former, but not the latter, are capable of catalyzing pre-tRNA maturation in vitro in the absence of proteins. An explanation of these functional differences will be assisted by a detailed comparison of bacterial and eukaryal RNase P RNA structures. However, the structures of eukaryal RNase P RNAs remain poorly characterized, compared to their bacterial and archaeal homologs. Hence, we have taken a phylogenetic-comparative approach to refine the secondary structures of eukaryal RNase P RNAs. To this end, 20 new RNase P RNA sequences have been determined from species of ascomycetous fungi representative of the genera Arxiozyma, Clavispora, Kluyveromyces, Pichia, Saccharomyces, Saccharomycopsis, Torulaspora, Wickerhamia, and Zygosaccharomyces. Phylogenetic-comparative analysis of these and other sequences refines previous eukaryal RNase P RNA secondary structure models. Patterns of sequence conservation and length variation refine the minimum-consensus model of the core eukaryal RNA structure. In comparison to bacterial RNase P RNAs, the eukaryal homologs lack RNA structural elements thought to be critical for both substrate binding and catalysis. Nonetheless, the eukaryal RNA retains the main features of the catalytic core of the bacterial RNase P. This indicates that the eukaryal RNA remains intrinsically a ribozyme.

Animals↗
PubMedDate not supplied

Predicting dye biodegradation from redox potentials.

Two biological approaches for decolorization of azo sulfonated dyes have been compared: reductive decolorization with the ascomycete yeast Issatchenkia occidentalis and enzymatic oxidative decolorization with Trametes villosa laccase alone or in the presence of the mediator 1-hydroxybenzotriazole. The redox potential difference between the biological cofactor involved in the reductive activity of growing cells and the azo dye is a reliable indication for the decolorization ability of the biocatalyst. A linear relationship exists between the redox potential of the azo dyes and the decolorization efficiency of enzyme, enzyme/mediator, and yeast. The less positive the anodic peak of the dye, the more easily it is degraded oxidatively with laccase. The more positive the cathodic peak of the dye, the more rapidly the dye molecule is reduced with yeast.

Algorithms↗
PubMed2025

Enzymatic Anti-Baldwin Ring-Closure Cascade for Fused Bicyclic Ether Formation.

Pyrenulic acids are cytotoxic polyketides isolated from the ascomycete Pyrenula sp. derived from Vietnamese lichen that are characterized by complex fused cyclic core structures. Genome sequencing, in silico sequence analysis, and RT-PCR studies identified the pyrenulic acid (pya) biosynthetic gene cluster. Based on a functional analysis of the enzymes by expression of each gene in a heterologous host using Aspergillus nidulans, we discovered two cytochrome P450s PyaJ and PyaG that effect epoxidation and hydroxylation of the alkyl chain terminal, respectively, and an α/β hydrolase PyaF that constructs a 6- and 7-membered fused bicyclic diether skeleton by catalyzing successive epoxide ring-opening 6-endo and 7-endo cyclization reactions. To elucidate the detailed mechanism of pyrenulic acid formation, we obtained PyaF as a recombinant enzyme and performed an in vitro experiment, which confirmed catalysis by PyaF of the cyclization reaction. In addition, we performed alignment analysis of PyaF with α/β hydrolases with known functions, as well as an in-depth computational study. In-depth computational analyses of the cyclization reaction pathways with density functional theory quantum mechanics and detailed characterization of PyaF by Chai-1-based protein structure modeling with molecular dynamics simulations and site-specific mutagenesis predicted the active amino acid residues of this serine α/β hydrolase to be an unusual catalytic serine tetrad involving Ser170, Asn342, Asp314, and His169, with Tyr255 and His284 acting as general bases to facilitate opening of the epoxides. Our study provides insight into how regioselectivity of enzymatic anti-Baldwin epoxide ring-opening cascades for the formation of a fused cyclic ether structure is controlled.

Cyclization↗
PubMed2001

Broad-spectrum antimicrobial activity in vitro of the synthetic peptide D4E1.

Broad-spectrum antimicrobial activity of a synthetic peptide, D4E1, is documented in this paper. D4E1 inhibited the growth of several fungal phytopathogens belonging to four classes-Ascomycetes, Basidiomycetes, Deuteromycetes, and Oomycetes, and two bacterial pathogens, Pseudomonas syringae pv. tabaci and Xanthomonas campestris pv. malvacearum race 18. The minimum inhibitory concentration (MIC) of D4E1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microM. Fungal pathogens highly sensitive to D4E1 include Thielaviopsis basicola, Verticillium dahliae, Fusarium moniliforme, Phytophthora cinnamomi, and Phytophthora parasitica. Comparatively, the least sensitive fungal pathogens were Alternaria alternata, Colletotrichum destructivum, and Rhizoctonia solani. The two bacterial pathogens, P. syringae pv. tabaci and X. campestris pv. malvacearum race 18, were most sensitive to D4E1 with MIC values of 2.25 and 1.25 microM, respectively. Microscopic analysis of D4E1 effects on fungal morphology of Aspergillus flavus and R. solani revealed abnormal hyphal growth and discontinuous cytoplasm. After 8 h of exposure to 25 microM D4E1, A. flavus spore germination was reduced by 75%. The suitability of peptide D4E1 to enhance disease resistance in transgenic crop plants is discussed.

Anti-Bacterial Agents↗
PubMed2002

Fungal flora and ochratoxin a production in grapes and musts from france.

Eleven samples of grapes and musts used in red table wines were investigated for the occurrence of potential ochratoxin A (OTA)-producing molds. From these samples, 59 filamentous fungi and 2 yeasts were isolated. Among the 30 genera isolated, Deuteromycetes were the most frequent (70%) followed by Ascomycetes (10%). Six of the eleven grapes samples were contaminated by potentially ochratoxinogenic strains (Penicillium chrysogenum and Aspergillus carbonarius). When cultivated in vitro on solid complex media, the 14 strains of A. carbonarius produced OTA. No other species produced OTA under the same conditions. Among must samples, eight of eleven were found to be contaminated by OTA (concentrations from <10 to 461 ng/L). There is a strong correlation between the presence of ochratoxin-producing strains on grapes and OTA in musts. These findings should be connected with the OTA contamination of human blood in these areas and in France.

Food Handling↗
PubMed2002

Eutypa dieback in grapevines: differential production of acetylenic phenol metabolites by strains of Eutypa lata.

The production of acetylenic phenol metabolites in vitro by three strains of the ascomycete Eutypa lata, the causative agent of dying-arm disease in grapevines, has been investigated. Metabolite composition and yields differed significantly between strains and with growth medium but usually reached a maximum after 24-30 days of fungal growth. A general method for the analysis and identification of metabolites by gas chromatography/mass spectrometry of their trimethylsilyl ether derivatives was developed and individual compounds were quantitated by analytical high-performance liquid chromatography (HPLC) and separated by preparative HPLC. The phenolic aldehyde, eutypine (1), reported to be the grape phytotoxin, occurred in only one of the strains examined whereas the primary metabolite was the corresponding alcohol, eutypinol (2), the presumptive detoxification product. A novel metabolite was isolated as a major constituent, together with a minor component, and their structures were established by spectroscopic methods as a methoxyquinol, named eulatinol (4), and a chromene analog (9) of 2, respectively. The evidence suggests that 1 is not solely responsible for phytotoxicity in grapevines but that dying-arm disease may result from a suite of compounds elaborated by the fungus, with the composition dependent on fungal strain and nutritional source.

Alkynes↗
PubMed2004

Fungistatic and bacteriostatic activities of alkamides from Heliopsis longipes roots: affinin and reduced amides.

This work demonstrates the fungistatic and bacteriostatic activities of affinin, the main alkamide of Heliopsis longipes (Gray) Blake (Asteraceae) roots and two alkamides obtained by catalytic reduction of affinin: N-isobutyl-2E-decenamide and N-isobutyl-decanamide. The bioactivity was tested against Rhizoctonia solani groups AG3 and AG5, Sclerotium rolfsii, Sclerotium cepivorum, Fusarium sp., Vertcillium sp., phytopathogenic fungi; Phytophthora infestans, a phytopathogenic Chromista; Saccharomyces cerevisiae, a nonphytopathogenic ascomycete; and Escherichia coli, Erwinia carotovora, and Bacillus subtilis, bacteria. Affinin, being the primary component of the lipidic fraction, is expected to be responsible for the fungitoxic activity observed in roots of this plant species. Four of the assayed fungi showed an important sensitivity to the presence of affinin: S. rolfsii, S. cepivorum, P. infestans, and R. solani AG-3 and AG-5, displaying a growth inhibition of 100%. S. cerevisiaeshowed a similar growth inhibition with affinin. None of the alkamides obtained by catalytic reduction of affinin showed a fungitoxic activity. Affinin had a definite negative effect on the growth of E. coli and B. subtilis, but E. carotovora carotovora was not sensitive to the highest dose of affinin assayed. N-Isobutyl-2E-decenamide displayed a higher bacteriostatic activity against E. coli and E. carotovora carotovora. In both cases, this alkamide was more potent than affinin. On the other hand, only N-isobutyl-decanamide displayed a significant activity on the growth of B. subtilis.

Alkenes↗
PubMed2005

Dying-arm disease in grapevines: diagnosis of infection with Eutypa lata by metabolite analysis.

Dying-arm disease in grapevines, produced by infection with the ascomycete Eutypa lata, is responsible for major production losses in vineyards. Dieback of the shoots and cordon is believed to be due to acetylenic phenol metabolites produced by the fungus. To identify specific metabolites that could potentially be used for diagnosis of infection, eight E. lata isolates were grown in vitro on hot water extracts from grape varieties with various degrees of tolerance to the foliar symptoms of E. lata dieback. HPLC analysis showed that eutypinol was consistently produced in large amounts, together with smaller amounts of methyleutypinol and eulatachromene; eutypine, the putative toxin, was produced solely on Sauvignon Blanc extract and then in only barely detectable amounts. When E. lata isolates from Cabernet Sauvignon and Merlot were grown on identical media, the amounts of metabolites produced differed significantly between isolates but the pattern of metabolites was quite similar, with eutypinol again predominating. The consistent production of eutypinol indicated that this was the most suitable metabolite for which to analyze in order to diagnose the presence of E. lata. Extraction and analysis of grapevine tissues exhibiting symptoms of dieback failed to show the presence of any metabolites. However, when infected cordon sections were placed in water and cultured for 5 days, eutypinol was readily detected in the aqueous solution; metabolites were not produced from uninfected tissue. This provides a method for detection of infected tissue and indicates that the toxic metabolites react at the point of production, disrupting the vascular structure and inhibiting transport of nutrients, rather than being translocated to tissues that exhibit symptoms.

Ascomycota↗
PubMed2004

New peptaibols from Mycogone cervina.

From cultures of Mycogone cervina, a mycophilic fungus growing on the fruit bodies of ascomycete Paxina acetabulum, two new peptaibols (cervinin, N-Ac-Leu-Aib-Pro-Aib-Leu-Aib-Pro-Ala-Aib-Pro-Val-red-Leu (1) and the red-Leu O-acetylated derivative 2) were isolated. The structures of 1 and 2 were elucidated by spectroscopic techniques. They exhibited weak antibacterial as well as cytotoxic activities. They are the first secondary metabolites described from M. cervina.

Animals↗
PubMed2004

New azaphilones from the inedible mushroom Hypoxylon rubiginosum.

Fractionation of the methanol extract of the fruit bodies of the xylariaceus ascomycete Hypoxylon rubiginosum resulted in the isolation of three new azaphilone derivatives named rubiginosins A-C (1-3) and a new fatty acid named rubiginosic acid (4), together with three known compounds, entonaemin A (5), daldinin C (6), and orsellinic acid. Their structures were elucidated by 2D NMR, MS, IR, and UV spectra and chemical reaction. The absolute configuration of compound 3 was established by CD spectroscopy. The structure of 4 was confirmed by X-ray crystallographic analysis.

Agaricales↗
PubMed2005

Roquefortine E, a diketopiperazine from an Australian isolate of Gymnoascus reessii.

The new isoprenylated diketopiperazine roquefortine E (6) has been isolated from an Australian soil isolate of the ascomycete Gymnoascus reessii. The known fungal metabolite roquefortine C (1) was also recovered as the major antibacterial principle, and all structures were assigned by detailed spectroscopic analysis.

Anti-Bacterial Agents↗
PubMed1997

Soil mycoflora from the Dead Sea Oases of Ein Gedi and Einot Zuqim (Israel).

Samples were taken from the top 10 cm of soils from 24 points in the Ein Gedi area. Among 329 isolates, 142 species were identified: 11 genera of ascomycetes, one genus of coelomycetes, 28 genera of hyphomycetes, 7 genera of zygomycetes and one yeast, in addition to some unidentified basidiomycetes. The hyphomycetes were represented by 17 dematiaceous, 9 mucedinaceous and two tuberculariaceous. Melanconiaceous and stilbellaceous genera were not found. Two new varieties of Microascus recently described were reisolated. No strict thermophiles or halophiles were obtained. There is apparently no very characteristic or specific fungal flora of the Dead Sea Oases although it was different from that found in the desert soil surrounding this area.

Ecology↗
PubMed1997

Coniosporium perforans and C. apollinis, two new rock-inhabiting fungi isolated from marble in the Sanctuary of Delos (Cyclades, Greece).

Coniosporium perforans and C. apollinis, originating from marble in the Mediterranean basin, are described as new species of rock inhabiting microcolonial fungi. The morphologically similar species Monodictys castaneae (Wallr.) S. Hughes, Phaeosclera dematioides Sigler et al., and a Coniosporium-like strain are compared using 18S rDNA phylogeny and Restriction Length Fragment Polymorphism analysis of Internal Transcribed Spacer regions. Sarcinomyces crustaceus Lindner is additionally compared on the basis of 18S rDNA sequencing data. Phylogenetic analysis suggests that Phaeosclera dematioides is related to the ascomycetous order Dothideales and Monodictys castaneae to the Pleosporales, whereas the three Coniosporium species studied are a sister group to the Herpotrichiellaceae (Chaetothyriales). A similar affinity was suggested previously for the recently described meristematic rock-fungus Sarcinomyces petricola Wollenzien & de Hoog. Sarcinomyces crustaceus appears unrelated to this group, and hence the present new taxa cannot be described in this genus.

Base Sequence↗
PubMed2000

Halotolerance of the yeast Arxula adeninivorans LS3.

The non-pathogenic, dimorphic, ascomycetous yeast Arxula adeninivorans LS3 is halotolerant. It can grow in a minimal medium containing up to 20% NaCl. The growth parameters are only weakly influenced by 10% NaCl. However, NaCl in a concentration higher than 10% causes a decrease in the specific growth rate, a longer adaptation phase and a lower cell count in the stationary growth phase. Concentrations of glycerol and trehalose, which differed 100-fold in magnitude in a salt free medium, are also influenced differently by salt. NaCl induces accumulation of intracellular glycerol in exponentially growing cells but a reduced concentration of intracellular trehalose in stationary cells. Transcripts of the genes ARFC3, encoding a component of the replication factor C, and GAA, encoding a secretory glucoamylase, can be detected only in cells cultured in media with NaCl concentrations below 10%. Furthermore, NaCl in high concentration reduces the level of secreted proteins including glucoamylase end invertase.

Adaptation, Biological↗
PubMedDate not supplied

Isolation of Hanseniaspora uvarum (Kloeckera apiculata) in humans.

Isolation of Hanseniaspora uvarum, a yeast of the ascomycetes group, whose anamorph corresponds to Kloeckera apiculata, obtained from stool and two ungual specimens from three patients, is reported. This yeast has been found in soil, water, various fruits, bivalve molluscs, crabs, prawns and fruit flies; in Spain, it has been described in the fermentation processes of some wines. In our region, it has also been found in the intestine of mackerel (Scomber scombrus). Its finding in humans constitutes a clinical rarity.

Adult↗