Inactivation of stress-resistant ascospores of Eurotiales by industrial sanitizers.

Different fungi, including the genera Aspergillus (Neosartorya), Paecilomyces (Byssochlamys) and Talaromyces, produce (asco)spores that survive pasteurization treatments and are regarded as the most stress-resistant eukaryotic cells. The sensitivity of the ascospores to treatments with industrial sanitizers containing chlorine dioxide and iodine (iodophors) has never been assessed before. Ascospores of 4 species of Eurotiales were tested and showed clear variations in sensitivity. The most resilient species, T. macrosporus and Pae. variotii (=B. spectabilis) survive 75, but not 200 ppm chlorine dioxide solution treatments. These species were able to survive 75 ppm iodine solution treatments, but relatively low amounts of ascospores (100-1000 spores) could be inactivated after 16 h of treatment. Inactivated spores did not show any sign of germination after 7 days following treatment on growth medium. As judged by microscopy, iodine inactivation resulted in visibly distorted ascospores. For the interpretation of results, the state of dormancy or activation of ascospores is highly important.

Overlooked competing asexual and sexually typified generic names of Ascomycota with recommendations for their use or protection.

With the change to one scientific name for fungal species, numerous papers have been published with recommendations for use or protection of competing generic names in major groups of ascomycetes. Although genera in each group of fungi were carefully considered, some competing generic names were overlooked. This paper makes recommendations for additional competing genera not considered in previous papers. Chairs of relevant Working Groups of the ICTF were consulted in the development of these recommendations. A number of generic names need protection, specifically Amarenographium over Amarenomyces, Amniculicola over Anguillospora, Balansia over Ephelis, Claviceps over Sphacelia, Drepanopeziza over Gloeosporidiella and Gloeosporium, Golovinomyces over Euoidium, Holwaya over Crinium, Hypocrella over Aschersonia, Labridella over Griphosphaerioma, Metacapnodium over Antennularia, and Neonectria over Cylindrocarpon and Heliscus. The following new combinations are made: Amniculicola longissima, Atichia maunauluana, Diaporthe columnaris, D. liquidambaris, D. longiparaphysata, D. palmicola, D. tersa, Elsinoë bucidae, E.caricae, E. choisyae, E. paeoniae, E. psidii, E. zorniae, Eupelte shoemakeri, Godronia myrtilli, G. raduloides, Sarcinella mirabilis, S. pulchra, Schizothyrium jamaicense, and Trichothallus niger. Finally, one new species name, Diaporthe azadirachte, is introduced to validate an earlier name, and the conservation of Discula with a new type, D. destructiva, is recommended.

Effects of Seven Fungicides on Non-Target Aquatic Fungi.

Aquatic risk assessments for fungicides are carried out without information on their toxicity to non-target aquatic fungi. This might cause an underestimation of the toxic effects to the aquatic fungal community. This study focuses on the question whether recently derived concentrations limits for fungicides considered to protect populations of primary producers and (in)vertebrates also do protect the aquatic fungi. A panel of fungal species and Oomycetes was isolated and identified from unpolluted surface waters in the Netherlands. Toxicity tests were used to determine effects of seven fungicides with different modes of actions. For the triazoles epoxiconazole and tebuconazole, the chronic lowest observable effect concentration was lower than the regulatory acceptable concentration based on acute HC5 values.

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88.

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.

Distribution of sterigmatocystin in filamentous fungi.

During the last 50y, the carcinogenic mycotoxin sterigmatocystin (ST) has been reported in several phylogenetically and phenotypically different genera: Aschersonia, Aspergillus, Bipolaris, Botryotrichum, Chaetomium, Emericella, Eurotium, Farrowia, Fusarium, Humicola, Moelleriella, Monocillium and Podospora. We have reexamined all available strains of the original producers, in addition to ex type and further strains of each species reported to produce ST and the biosynthetically derived aflatoxins. We also screened strains of all available species in Penicillium and Aspergillus for ST and aflatoxin. Six new ST producing fungi were discovered: Aspergillus asperescens, Aspergillus aureolatus, Aspergillus eburneocremeus, Aspergillus protuberus, Aspergillus tardus, and Penicillium inflatum and one new aflatoxin producer: Aspergillus togoensis (=Stilbothamnium togoense). ST was confirmed in 23 Emericella, four Aspergillus, five Chaetomium, one Botryotrichum and one Humicola species grown on a selection of secondary metabolite inducing media, and using multiple detection methods: HPLC-UV/Vis DAD, - HRMS and - MS/MS. The immediate precursor for aflatoxin, O-methylsterigmatocystin was found in Chaetomium cellulolyticum, Chaetomium longicolleum, Chaetomium malaysiense and Chaetomium virescens, but aflatoxin was not detected from any Chaetomium species. In all 55 species, representing more than 11 clades throughout the Pezizomycotina, can be reliably claimed to be ST producers and 13 of these can also produce aflatoxins. It is not known yet whether the ST/aflatoxin pathway has been developed independently 11 times, or is the result of partial horizontal gene transfer.

Trehalose degradation and glucose efflux precede cell ejection during germination of heat-resistant ascospores of Talaromyces macrosporus.

Talaromyces macrosporus forms ascospores that survive pasteurization treatments. Ascospores were dense (1.3 g ml(-1)), relatively dry [0.6 g H(2)O (g dry weight)(-1)] and packed with trehalose (9-17% fresh weight). Trehalose was degraded to glucose monomers between 30 and 100 min after heat activation of the spores. The maximal activity of trehalase was calculated as 400-520 nmol glucose formed min(-1) (mg protein)(-1) as judged by measurements of the trehalose content of spores during germination. During early germination, glucose was released from the cell (10% of the cell weight or more). The intracellular concentration of glucose only peaked briefly. After 160-200 min, the protoplast encompassed by the inner cell wall was ejected through the outer cell wall in a very quick process. Subsequently, respiration of spores increased strongly. The data suggested that trehalose is primarily present for the protection of cell components as glucose is released from the cell. Then, an impenetrable outer cell wall is shed before metabolic activity increases.