New records of Oleoguttula mirabilis and Rachicladosporium antarcticum from James Ross Island, Antarctica

A group of seven isolates of black meristematic fungi was collected from rocks within the framework of mycological research focused on the study of diversity of rock-inhabiting fungi on James Ross Island in Antarctica. Their identification was based on ITS rDNA sequence comparisons supported by morphological data. Obtained results assigned four analysed strains as Oleoguttula mirabilis and three isolates as Rachicladosporium antarcticum. To the best of our knowledge this is the second report of isolation of these two psychrophilic species from different parts of James Ross Island which imply that they probably represent a common part of its environmental microbial flora.

Austrostigmidium, a new austral genus of lichenicolous fungi close to rock-inhabiting meristematic fungi in Teratosphaeriaceae

The new genus of lichenicolous fungi Austrostigmidium is described from Antarctica and Tierra del Fuego (Chile). It is characterized by the presence of black pseudothecia, pseudoparaphyses, fissitunicate, I−, KI− asci and 3-septate hyaline ascospores. So far, the only known species grows on Mastodia tessellata (Verrucariales, Eurotiomycetes). The new genus is compared with anatomically close genera. Based on nuLSU and nuSSU markers we inferred its phylogenetic relationships and found that it belongs to the family Teratosphaeriaceae (Capnodiales, Dothideomycetes) and is closely related to rock-inhabiting fungal species, as well as to the hyphomycetous lichenicolous fungus Xanthoriicola. Finally, the host-parasite interface has been analyzed by means of transmission electron microscopy and fluorescence microscopy in order to describe the interactions among the new fungus and the symbionts forming the host lichen.

Two new dothideomycetous endoconidial genera from declining larch

Two endoconidial, black meristematic fungi, Celosporium larixicolum gen. et sp. nov. (Dothideales) and Hispidoconidioma alpina gen. et sp. nov. (Capnodiales) are described from black subicula on twigs of declining larch ( Larix lyallii Parl) trees in Alberta, Canada. Conidioma morphology and phylogenetic analysis of LSU and ITS regions indicate that these taxa are both distinct from each other and from previously described endoconidial genera. Conidiomata of C. larixicolum consist of black cellular clumps (aggregated conidiogenous cells) that are either naked or enveloped by scant to dense mycelium that sometimes organizes into a cupulate peridium. Endoconidia are 1–3 celled, hyaline when released but become pigmented as they age, and very variable in size and shape, e.g., globose, pear-shaped, osteoid, or discoid with an irregular flange. In H. alpina, colonies are three-layered, consisting of a central pseudoparenchymatous layer sandwiched between an upper and a basal hyphal layers, and conidiogenesis occurs in sporadic areas of the central layer. Endoconidia are unicellular, hyaline, and subglobose to ellipsoid. The strong phylogenetic affinities between these newly described taxa and slow-growing, melanized fungi isolated from rocks suggest individual black meristematic fungus lineages may have broad habitat ranges.

Synthetic Consolidants Attacked by Melanin-Producing Fungi: Case Study of the Biodeterioration of Milan (Italy) Cathedral Marble Treated with Acrylics

ABSTRACT Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.