Penicillium subrubescens, a new species efficiently producing inulinase

Inulin is a reserve carbohydrate in about 15 % of the flowering plants and is accumulated in underground tubers of e.g. chicory, dahlia and Jerusalem artichoke. This carbohydrate consists of linear chains of β-(2,1)-linked fructose attached to a sucrose molecule. Inulinases hydrolyse inulin into fructose and glucose. To find efficient inulin degrading fungi, 126 fungal strains from the Fungal Biotechnology Culture Collection (FBCC) at University of Helsinki and 74 freshly isolated strains from soil around Jerusalem artichoke tubers were screened in liquid cultures with inulin as a sole source of carbon or ground Jerusalem artichoke tubers, which contains up to 19 % (fresh weight) inulin. Inulinase and invertase activities were assayed by the dinitrosalicylic acid (DNS) method and a freshly isolated Penicillium strain originating from agricultural soil (FBCC 1632) was the most efficient inulinase producer. When it was cultivated at pH 6 and 28 °C in 2 litre bioreactors using inulin and Jerusalem artichoke as a carbon source, inulinase and invertase activities were on day 4 7.7 and 3.1 U mL^?1, respectively. The released sugars analysed by TLC and HPLC showed that considerable amounts of fructose were released while the levels of oligofructans were low, indicating an exoinulinase type of activity. Taxonomic study of the inulinase producing strain showed that this isolate represents a new species belonging in Penicillium section Lanata-divaricata. This new species produces a unique combination of extrolites and is phenotypically and phylogenetically closely related to Penicillium pulvillorum. We propose the name Penicillium subrubescens sp. nov. (CBS 132785^T = FBCC 1632^T) for this new species.     

Two novel <Emphasis Type="Italic">Aspergillus</Emphasis> species from hypersaline soils of The National Park of Lake Urmia,Iran

Two novel Aspergillus species, one belonging to the section Terrei and the other to section Flavipedes, were isolated from hypersaline soils of The National Park of Lake Urmia (Iran) and are here described as Aspergillus iranicus and Aspergillus urmiensis. A polyphasic taxonomic approach comprising extrolite profiles, phenotypic characters and molecular data (beta-tubulin, calmodulin and ribosomal polymerase II second largest subunit gene sequences) was applied to determine their novel taxonomic status. Aspergillus iranicus (CBS 139561^T) is phylogenetically related to A. carneus, A. niveus, A. allahabadii and A. neoindicus, and it can be differentiated from those species by a unique extrolite pattern (citrinin, gregatins, and a terrequinone) and its conidial colour. Aspergillus urmiensis (CBS 139558^T) shares a most recent common ancestor with A. templicola. The former species produces globose vesicles, and those of A. templicola are predominantly elongate. The Aspergillus urmiensis isolates produce several uncharacterized extrolites. Two other strains obtained during this study reside in a clade, together with the type strain of A. movilensis (CCF 4410^T), and are identified accordingly. Based on the phylogenetic data presented in this study, A. frequens is reduced to synonymy with A. micronesiensis and A. mangaliensis is considered to be a synonym of A. templicola.     

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.     

Zygomycota associated with traditional meju, a fermented soybean starting material for soy sauce and soybean paste

Various zygomycota species were detected during a study of the mycobiota of meju, a brick of dried fermented soybeans, used in Korean cuisine. Two hundred and sixty-eight strains were isolated from 98 finished meju products collected in various regions of Korea from 2009 to 2011, and 96 strains were isolated from in-process meju on various farms from 2010 to 2011. The isolated zygomycota were identified using phenotypic characteristics combined with DNA sequences of the internal transcribed spacer regions of ribosomal DNA and the D1/D2 nuclear ribosomal large subunit. Of 364 zygomycota strains, 108 were identified as Mucor circinelloides, 96 as M. racemosus, 60 as Lichtheimia ramosa, 22 as Rhizopus stolonifer, 16 as Lichtheimia corymbifera, and the other 62 strains comprised 10 other species. The psychrotrophic species, Mucor circinelloides and M. racemosus were predominantly present during low temperature fermentation (LTF) and the thermotolerant species Lichtheimia ramosa and Rhizomucor species were predominant during high temperature fermentation (HTF). The results suggest that temperature has a large influence on the zygomycota composition during the fermentation process of meju.     

Xerotolerant Cladosporium sphaerospermum Are Predominant on Indoor Surfaces Compared to Other Cladosporium Species

Indoor fungi are a major cause of cosmetic and structural damage of buildings worldwide and prolonged exposure of these fungi poses a health risk. Aspergillus, Penicillium and Cladosporium species are the most predominant fungi in indoor environments. Cladosporium species predominate under ambient conditions. A total of 123 Cladosporium isolates originating from indoor air and indoor surfaces of archives, industrial factories, laboratories, and other buildings from four continents were identified by sequencing the internal transcribed spacer (ITS), and a part of the translation elongation factor 1α gene (TEF) and actin gene (ACT). Species from the Cladosporium sphaerospermum species complex were most predominant representing 44.7% of all isolates, while the Cladosporium cladosporioides and Cladosporium herbarum species complexes represented 33.3% and 22.0%, respectively. The contribution of the C. sphaerospermum species complex was 23.1% and 58.2% in the indoor air and isolates from indoor surfaces, respectively. Isolates from this species complex showed growth at lower water activity (≥ 0.82) when compared to species from the C. cladosporioides and C. herbarum species complexes (≥ 0.85). Together, these data indicate that xerotolerance provide the C. sphaerospermum species complex advantage in colonizing indoor surfaces. As a consequence, C. sphaerospermum are proposed to be the most predominant fungus at these locations under ambient conditions. Findings are discussed in relation to the specificity of allergy test, as the current species of Cladosporium used to develop these tests are not the predominant indoor species.     

Aspergillus calidoustus sp. nov., causative agent of human infections previously assigned to Aspergillus ustus

Aspergillus ustus is a relatively rare human pathogen causing invasive infections in immunocompromised hosts. In this study isolates originating from clinical and other sources have been examined using molecular, morphological, and physiological approaches to clarify their species assignment. Phylogenetic analysis of partial beta-tubulin, calmodulin, actin, and intergenic transcribed spacer sequences indicated that none of the clinical isolates recognized previously as A. ustus belongs to this species. All but two of these isolates formed a well-defined clade related to A. pseudodeflectus based on sequence analysis of protein-coding regions. Morphological and physiological examination of these isolates indicated that they are able to grow above 37 degrees C, in contrast with A. ustus isolates, and give a positive Ehrlich reaction, in contrast with related species including A. granulosus, A. ustus, and A. pseudodeflectus. These isolates are proposed as a new species, A. calidoustus. Antifungal susceptibility testing showed that this species has decreased susceptibilities to several antifungal drugs. The triazoles are inactive in vitro, including the new azole posaconazole.     

Four novel <Emphasis Type="Italic">Talaromyces</Emphasis> species isolated from leaf litter from Colombian Amazon rain forests

Various Talaromyces strains were isolated during a survey of fungi involved in leaf litter decomposition in tropical lowland forests in the Caquetá and Amacayacu areas of the Colombian Amazon. Four new Talaromyces species are described using a polyphasic approach, which includes phenotypic characters, extrolite profiles and phylogenetic analysis of the internal transcribed spacer region (ITS) barcode, and beta-tubulin (BenA) and calmodulin (CaM) gene regions. Talaromyces amazonensis sp. nov., T. francoae sp. nov. and T. purgamentorum sp. nov. belong to Talaromyces section Talaromyces, and T. columbiensis sp. nov. is located in section Bacillispori. The new species produce several bioactive compounds: T. amazonensis produces the potential anticancer agents duclauxin, berkelic acid and vermicillin, and T. columbiensis produces the effective anticancer agent wortmannin (together with duclauxin). In addition to the new species, T. aculeatus and T. macrosporus were isolated during this study on leaf litter decomposition.     

Unveiling the fungal mycobiota present throughout the cork stopper manufacturing process

A particular fungal population is present in the main stages of the manufacturing process of cork discs. Its diversity was studied using both dependent (isolation) and independent culture methods (denaturing gel gradient electrophoresis and cloning of the ITS1-5.8S-ITS2 region). The mycobiota in the samples taken in the stages before and after the first boiling seems to be distinct from the population in the subsequent manufacturing stages. Most isolated fungi belong to the genera Penicillium, Eurotium and Cladosporium. The presence of uncultivable fungi, Ascomycota and endophytes in raw cork was confirmed by sequencing. The samples taken after the first boiling contained uncultivable fungi, but in a few samples some isolated fungi were also detected. The main taxa present in the following stages were Chrysonilia sitophila, Penicillium glabrum and Penicillium spp. All applied techniques had complementary outcomes. The main factors driving the shift in cork fungal colonization seem to be the high levels of humidity and temperature to which the slabs are subjected during the boiling process.