Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota).

The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.

Myosin XI is associated with fitness and adaptation to aridity in wild pearl millet.

Phenotypic changes in plants can be observed along many environmental gradients and are determined by both environmental and genetic factors. The identification of alleles associated with phenotypic variations is a rapidly developing area of research. We studied the genetic basis of phenotypic variations in 11 populations of wild pearl millet (Pennisetum glaucum) on two North-South aridity gradients, one in Niger and one in Mali. Most of the 11 phenotypic traits assessed in a common garden experiment varied between the populations studied. Moreover, the size of the inflorescence, the number of flowers and aboveground dry mass co-varied positively with a decrease in rainfall. To decipher the genetic basis of these phenotypes, we used an association mapping strategy with a mixed model. We found two SNPs on the same myosin XI contig significantly associated with variations in the average number of flowers. Both the allele frequency of the two SNPs and the average number of flowers co-varied with the rainfall gradient on the two gradients. Interestingly, this gene was also a target of selection during domestication. The Myosin XI gene is thus a good candidate for fitness-related adaptation in wild populations.

Chemotherapy-induced differentiation to cure botryoid rhabdomyosarcoma: a case report and review of the literature.

Rhabdomyosarcoma (RMS) occurs rarely in adults and constitutes 2-6% of all uterine neoplasms. The authors report the case of a 26-year-old woman diagnosed with botryoid RMS that presented discordant progression results on follow up imaging and cytodifferentiation on pathologic control. This case showed that radiological evaluation could be misleading as the tumor demonstrated chemotherapy-induced differentiation without volume reduction. This case illustrates the limitations of using the imaging anatomical dimensions of sarcomas for treatment planning and highlights the potential role of functional imaging to assess the response to treatment.

DNA barcoding of clinically relevant Cunninghamella species.

Mucormycosis caused, in part, by representatives of the genus Cunninghamella is a severe infection with high mortality in patients with impaired immunity. Several species have been described in the literature as etiologic agents. A DNA barcoding study using ITS rDNA and tef-1α provided concordance of molecular data with conventional characters. The currently accepted Cunninghamella species were well supported in phylogenetic trees of both markers except for C. septata with ITS that clustered in the C. echinulata clade. Sequence variability was distinctly higher for the ITS than for tef-1α. Intraspecific ITS variability of some of the species exceeded that between some closely related species, but the marker remained applicable for species identification. The most variable species for both markers was C. echinulata. Cunninghamella bertholletiae is the main pathogenic species; infections by C. blakesleeana, C. echinulata, and C. elegans are highly exceptional.

Susceptibility and diversity in the therapy-refractory genus scedosporium.

Scedosporium species show decreased susceptibility to the majority of systemic antifungal drugs. Acquired resistance is likely to disseminate differentially with the mode of exchange of genetic material between lineages. Inter- and intraspecific diversities of Scedosporium species were analyzed for three partitions (rDNA internal transcribed spacer gene [ITS], partial ß-tubulin gene, and amplified fragment length polymorphism profiles), with the aim to establish distribution of resistance between species, populations, and strains. Heterogeneity of and recombination between lineages were determined, and distances between clusters were calculated using a centroid approach. Clinical, geographic, and antifungal data were plotted on diversity networks. Scedosporium minutisporum, Scedosporium desertorum, and Scedosporium aurantiacum were distinguished unambiguously in all partitions and had differential antifungal susceptibility profiles (ASP). Pseudallescheria fusoidea and Pseudallescheria ellipsoidea were indistinguishable from Scedosporium boydii. Pseudallescheria angusta took an intermediate position between Scedosporium apiospermum and S. boydii. Scedosporium boydii and S. apiospermum had identical ASP. Differences in (multi)resistance were linked to individual strains. S. apiospermum and S. boydii showed limited interbreeding and were recognized as valid, sympatric species. The S. apiospermum/S. boydii group, comprising the main clinically relevant Scedosporium species, consists of separate lineages and is interpreted as a complex undergoing sympatric evolution with incomplete lineage sorting. In routine diagnostics, the lineages in S. apiospermum/S. boydii are indicated with the umbrella descriptor "S. apiospermum complex"; individual species can be identified with rDNA ITS with 96.3% confidence. Voriconazole is recommended as the first-line treatment; resistance against this compound is rare.

Corrosion and creep resistance of some dental amalgam alloys.

Corrosion behaviour, creep values and phase transformation of conventional, admixed, unicompositional and two palladium-enriched amalgam alloys were investigated. Weight-loss method and solution analysis for dissolved metal ions were used. Creep values were determined after different immersion periods. X-ray diffraction was carried out to follow up phase transformation after different immersion periods and/or aging in dry air at 37 degrees up to one year. The results have shown that addition of palladium has improved corrosion and creep resistance and reduced gamma 1 to beta 1 phase transformation, and that gamma 2 did not appear again in high copper or palladium-enriched amalgam up to one year.

A comparative electrochemical study of corrosion susceptibility of some Pd-enriched amalgams.

Cyclic polarization technique was used to determine the corrosion susceptibility of some Pd-enriched amalgams as compared with the conventional and high-copper ones. Different oxidation and reduction peaks and their corresponding current intensities were determined in each case. Corrosion indices I and II were also calculated. Pd-enriched amalgams have shown lower corrosion susceptibility than conventional or unicompositional high-copper amalgams. A role was attributed to the alloy composition and the relative cathodic (reduction) current available.