New Penicillium and Talaromyces species from honey, pollen and nests of stingless bees.

Penicillium and Talaromyces species have a worldwide distribution and are isolated from various materials and hosts, including insects and their substrates. The aim of this study was to characterize the Penicillium and Talaromyces species obtained during a survey of honey, pollen and the inside of nests of Melipona scutellaris. A total of 100 isolates were obtained during the survey and 82% of those strains belonged to Penicillium and 18% to Talaromyces. Identification of these isolates was performed based on phenotypic characters and ß-tubulin and ITS sequencing. Twenty-one species were identified in Penicillium and six in Talaromyces, including seven new species. These new species were studied in detail using a polyphasic approach combining phenotypic, molecular and extrolite data. The four new Penicillium species belong to sections Sclerotiora (Penicillium fernandesiae sp. nov., Penicillium mellis sp. nov., Penicillium meliponae sp. nov.) and Gracilenta (Penicillium apimei sp. nov.) and the three new Talaromyces species to sections Helici (Talaromyces pigmentosus sp. nov.), Talaromyces (Talaromyces mycothecae sp. nov.) and Trachyspermi (Talaromyces brasiliensis sp. nov.). The invalidly described species Penicillium echinulonalgiovense sp. nov. was also isolated during the survey and this species is validated here.

Production of Secondary Metabolites in Extreme Environments: Food- and Airborne Wallemia spp. Produce Toxic Metabolites at Hypersaline Conditions.

The food- and airborne fungal genus Wallemia comprises seven xerophilic and halophilic species: W. sebi, W. mellicola, W. canadensis, W. tropicalis, W. muriae, W. hederae and W. ichthyophaga. All listed species are adapted to low water activity and can contaminate food preserved with high amounts of salt or sugar. In relation to food safety, the effect of high salt and sugar concentrations on the production of secondary metabolites by this toxigenic fungus was investigated. The secondary metabolite profiles of 30 strains of the listed species were examined using general growth media, known to support the production of secondary metabolites, supplemented with different concentrations of NaCl, glucose and MgCl2. In more than two hundred extracts approximately one hundred different compounds were detected using high-performance liquid chromatography-diode array detection (HPLC-DAD). Although the genome data analysis of W. mellicola (previously W. sebi sensu lato) and W. ichthyophaga revealed a low number of secondary metabolites clusters, a substantial number of secondary metabolites were detected at different conditions. Machine learning analysis of the obtained dataset showed that NaCl has higher influence on the production of secondary metabolites than other tested solutes. Mass spectrometric analysis of selected extracts revealed that NaCl in the medium affects the production of some compounds with substantial biological activities (wallimidione, walleminol, walleminone, UCA 1064-A and UCA 1064-B). In particular an increase in NaCl concentration from 5% to 15% in the growth media increased the production of the toxic metabolites wallimidione, walleminol and walleminone.

Two new Penicillium species Penicillium buchwaldii and Penicillium spathulatum, producing the anticancer compound asperphenamate.

Penicillium buchwaldii sp. nov. (type strain CBS 117181(T)  = IBT 6005(T)  = IMI 30428(T) ) and Penicillium spathulatum sp. nov. (CBS 117192(T)  = IBT 22220(T) ) are described as new species based on a polyphasic taxonomic approach. Isolates of P. buchwaldii typically have terverticillate conidiophores with echinulate thick-walled conidia and produce the extrolites asperphenamate, citreoisocoumarin, communesin A and B, asperentin and 5'-hydroxy-asperentin. Penicillium spathulatum is unique in having restricted colonies on Czapek yeast agar (CYA) with an olive grey reverse, good growth on CYA supplemented with 5% NaCl, terverticillate bi- and ter-ramulate conidiophores and consistently produces the extrolites benzomalvin A and D and asperphenamate. The two new species belong to Penicillium section Brevicompacta and are phylogenetically closely related to Penicillium tularense. With exception of Penicillium fennelliae, asperphenamate is also produced by all other species in section Brevicompacta (P. tularense, Penicillium brevicompactum, Penicillium bialowiezense, Penicillium olsonii, Penicillium astrolabium and Penicillium neocrassum). Both new species have a worldwide distribution. The new species were mainly isolated from indoor environments and food and feedstuffs. The fact that asperphenamate has been found in many widely different plants may indicate that endophytic fungi rather than the plants are the actual producers.

Two novel species of Aspergillus section Nigri from Thai coffee beans.

Two novel species of Aspergillus section Nigri from Thai coffee beans are described as Aspergillus aculeatinus sp. nov. and Aspergillus sclerotiicarbonarius sp. nov. Their taxonomic status was determined using a polyphasic taxonomic approach with phenotypic (morphology and extrolite profiles) and molecular (beta-tubulin, internal transcribed spacer and calmodulin gene sequences) characteristics. A. aculeatinus sp. nov. is a uniseriate species with a similar morphology to Aspergillus aculeatus and Aspergillus japonicus, but producing smaller conidia (2-5 microm). A. aculeatinus sp. nov. produced neoxaline, secalonic acid D and F, and aculeacins. A. sclerotiicarbonarius sp. nov. is a biseriate species similar to Aspergillus carbonarius and Aspergillus ibericus, but produces abundant sclerotia and some unique indol-alkaloids. The type strain of Aspergillus sclerotiicarbonarius sp. nov. is CBS 121057(T) (=IBT 28362(T)) and the type strain of Aspergillus aculeatinus sp. nov. is CBS 121060(T) (=IBT 29077(T)).

Fumonisin B2 production by Aspergillus niger.

The carcinogenic mycotoxin fumonisin B2 was detected for the first time in the industrially important Aspergillus niger. Fumonisin B2, known from Fusarium verticillioides and other Fusaria, was detected in cultures of three full genome sequenced strains of A. niger, in the ex type culture and in a culture of F. verticillioides by electrospray LC-MS analysis of methanolic extracts from agar plugs of cultures grown on several substrates. Whereas F. verticillioides produced fumonisins B1, B2, and B3 on agar media based on plant extracts, such as barley malt, oat, rice, potatoes, and carrots, A. niger produced fumonisin B2 best on agar media with a low water activity, including Czapek yeast autolysate agar with 5% NaCl. Of the media tested, only rice corn steep agar supported fumonisin production by both F. verticillioides and A. niger. However, A. niger had a different regulation of fumonisin production and a different quantitative profile of fumonisins, producing only B2 as compared to F. verticillioides. Fumonisin production by A. niger, which is a widely occurring species and an extremely important industrial organism, will have very important implications for biotechnology and especially food safety. A. niger is used for the production of citric acid and as producer of extracellular enzymes, and also as a transformation host for the expression of heterologous proteins. Certain strains of A. niger produce both ochratoxin A and fumonisins, so some foods and feeds may potentially contain two types of carcinogenic mycotoxins from this species.