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Kouvelis, V. N.

Publications and source records attributed to Kouvelis, V. N..

3 recordsLinked to original sources

Fungal pathogens exposed - genomic and phenotypic insights into Candida auris and its relatives of the Candida haemulonii species complex

Candida auris showed the world the ability of fungi to rapidly emerge as an urgent threat to public health. Close relatives of the Candida haemulonii complex exhibit also a similar multi-drug resistant nature and are increasingly reported as nosocomial pathogens. Here, we analyze both complete genomes assemblies and extensive phenotypic data for the five C. auris clades and pathogenic and non-pathogenic species related to the C. haemulonii species complex. First, we resolved the phylogeny of the species complex. Next, comparing C. auris to its pathogenic and non-pathogenic relatives we identified a pathogenic potential for the whole C. haemulonii species complex by shared gene content and phenotypic traits linked to drug resistance and virulence. In vivo virulence assays using the Galleria mellonella fungal infection model show that C. auris strains are significantly more virulent than any of the sibling species in the C. haemulonii complex. Phenotypic analysis links the increased virulence of C. auris to a more stress resistant phenotype compared to its siblings.

microbiology↗

Co-evolution of Large inverted repeats and G-quadruplex DNA in fungal mitochondria may facilitate mitogenome stability: the case of Malassezia

Mitogenomes are essential due to their contribution to cell respiration. Recently they have also been implicated in fungal pathogenicity mechanisms. Members of the basidiomycetous yeast genus Malassezia are an important fungal component of the human skin microbiome, linked to various skin diseases, bloodstream infections, and increasingly implicated in gut diseases and certain cancers. In this study, the comparative analysis of Malassezia mitogenomes contributed to phylogenetic tree construction for all species. The mitogenomes presented significant size and gene order diversity which correlates to their phylogeny. Most importantly, they showed the inclusion of Large Inverted Repeats (LIRs) and G-quadruplex (G4) DNA elements, rendering Malassezia mitogenomes a valuable test case for elucidating the evolutionary mechanisms responsible for this genome diversity. Both LIRs and G4s coexist and convergently evolved to provide genome stability through recombination. This mechanism is common in chloroplasts but, hitherto, rarely found in mitogenomes.

evolutionary biology↗

Mitogenomics and mitochondrial gene phylogeny decipher the evolution of Saccharomycotina yeasts

Saccharomycotina yeasts contain diverse clades within the kingdom of Fungi and are important to human everyday life. This work investigates the evolutionary relationships among these yeasts from a mitochondrial (mt) genomic perspective. A comparative study of 141 yeast mt genomes representing all major phylogenetic lineages of Saccharomycotina was performed, including genome size and content variability, intron and intergenic regions diversity, genetic code alterations and syntenic variation. Findings from this study suggest that mt genome size diversity is the result of a ceaseless random process mainly based on genetic recombination and intron mobility. Gene order analysis revealed conserved syntenic units and many occurring rearrangements, which can be correlated with major evolutionary events as shown by the phylogenetic analysis of the concatenated mt protein matrix. For the first time, molecular dating indicated a slower mt genome divergence rate in the early stages of yeast evolution, in contrast with a faster rate in the late evolutionary stages, compared to their nuclear time divergence. Genetic code reassignments of mt genomes are a perpetual process happening in many different parallel evolutionary steps throughout Saccharomycotina evolution. Overall, this work shows that phylogenetic studies that employ the mt genome of yeasts highlight major evolutionary events.

evolutionary biology↗