Publications by authors named "Hakim Tafer"

This study provides an example in the emerging field of biocodicology showing how metagenomics can help answer relevant questions that may contribute to a better understanding of the history of ancient manuscripts. To this end, two Slavonic codices dating from the 11th century were investigated through shotgun metagenomics. Endogenous DNA enabled to infer the animal origin of the skins used in the manufacture of the two codices, while nucleic sequences recovered from viruses were investigated for the first time in this material, opening up new possibilities in the field of biocodicology.

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Background: Jatropha curcas, a tropical shrub, is a promising biofuel crop, which produces seeds with high content of oil and protein. To better understand the maturation process of J. curcas seeds and to improve its agronomic performance, a two-step approach was performed in six different maturation stages of seeds: 1) generation of the entire transcriptome of J.

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Salt mines are among the most extreme environments as they combine darkness, low nutrient availability, and hypersaline conditions. Based on comparative genomics and transcriptomics, we describe in this work the adaptive strategies of the true halophilic fungus , found in a salt mine in Austria, and compare this strain to the ex-type halotolerant fungal strain . On a genomic level, exhibits a reduced genome size compared to , as well as a contraction of genes involved in transport processes.

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The black yeast is a polyextremophilic human pathogen, especially known for growing in man-made extreme environments. Reported diseases caused by this fungus range from benign cutaneous to systemic infections with 40% fatality rate. While the number of cases steadily increases in both immunocompromised and immunocompetent people, detailed knowledge about infection mechanisms, virulence factors and host response are scarce.

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Recent investigations have shown that xerophilic fungi may pose a biodeterioration risk by threatening objects of cultural heritage including many types of materials, including wood, paint layers, organic glues or leather and even metal. Historic—and also new built—pipe organs combine all those materials. In this study, halotolerant aspergilli and penicillia with low optimal temperatures were shown to be the most frequent invaders of pipe organs.

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× interspecies hybrid yeasts have frequently been isolated from alcoholic fermentation environments. Here, we report the draft genome sequence of the × HA1836 strain isolated from grapes from an Austrian vineyard.

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is an industrially relevant yeast frequently isolated from brewing environments. Here, we report the draft genome sequence of the HA2560 strain isolated from a municipal wastewater treatment plant.

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The fungal genus mostly comprises extremotolerant species from environmental sources, especially rock surfaces. The draft genome sequence of the rock fungus presented here is the first whole-genome sequence of the only species among black fungi known to have a nonmelanized spontaneous mutant.

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Cladophialophora immunda is an ascomycotal species belonging to the group of the black yeasts. These fungi have a thick and melanized cell wall and other physiological adaptations that allows them to cope with several extreme physical and chemical conditions. Member of the group can colonize some of the most extremophilic environments on Earth.

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The black yeast is a widespread polyextremophile and human pathogen, that is found in extreme natural habitats and man-made environments such as dishwashers. It can cause various diseases ranging from phaeohyphomycosis and systemic infections, with fatality rates reaching 40%. While the number of cases in immunocompromised patients are increasing, knowledge of the infections, virulence factors and host response is still scarce.

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Background: The ascomycetous family Chaetomiaceae (class Sordariomycetes) includes numerous soilborn, saprophytic, endophytic and pathogenic fungi which can adapt to various growth conditions and living niches by providing a broad armory of oxidative and antioxidant enzymes.

Results: We release the 34.7 Mbp draft genome of Chaetomium cochliodes CCM F-232 consisting of 6036 contigs with an average size of 5756 bp and reconstructed its phylogeny.

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A collection of 163 strains of black yeast-like fungi from the CBS Fungal Biodiversity Center (Utrecht, The Netherlands), has been screened for the ability to grow on hexadecane, toluene and polychlorinated biphenyl 126 (PCB126) as the sole carbon and energy source. These compounds were chosen as representatives of relevant environmental pollutants. A microtiter plate-based culture assay was set up in order to screen the fungal strains for growth on the selected xenobiotics versus glucose, as a positive control.

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In the current study a comparative proteomic approach was used to investigate the response of the human pathogen black yeast Exophiala dermatitidis toward temperature treatment. Protein functional analysis - based on cellular process GO terms - was performed on the 32 temperature-responsive identified proteins. The bioinformatics analyses and data presented here provided novel insights into the cellular pathways at the base of the fungus temperature tolerance.

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The yeast genus Debaryomyces comprises species isolated from various natural habitats, man-made environments, and clinical materials. Here, the draft genome of D. fabryi CBS 789(T), isolated from a human interdigital mycotic lesion, is presented.

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Unlabelled: The black yeast Exophiala dermatitidis is a worldwide distributed agent of primary and secondary diseases in both immunocompromised and healthy humans, with a high prevalence in human-made environments. Since thermo-tolerance has a crucial role in the fungus persistence in man-dominated habitat and in its pathogenicity, three incubation temperatures (37, 45, 1 °C) and two time spans (1 h, 1 week) were selected to simulate different environmental conditions and to investigate the effect of temperature on the proteome of E. dermatitidis CBS 525.

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A computational screen for novel small nucleolar RNAs in Drosophila melanogaster uncovered 15 novel snoRNAs and snoRNA-like long non-coding RNAs. In contrast to earlier surverys, the novel sequences are mostly poorly conserved and originate from unusual genomic locations. The majority derive from precurors antisense to well-known protein-coding genes, and four of the candidates are produced from exon-coding regions.

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Leonardo da Vinci's self-portrait is affected by foxing spots. The portrait has no fungal or bacterial infections in place, but is contaminated with airborne spores and fungal material that could play a role in its disfigurement. The knowledge of the nature of the stains is of great concern because future conservation treatments should be derived from scientific investigations.

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Exophiala dermatitidis (Wangiella dermatitidis) belongs to the group of the so-called black yeasts. Thanks in part to its thick and strongly melanized cell walls, E. dermatitidis is extremely tolerant to various kinds of stress, including extreme pH, temperature and desiccation.

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The fungal genus Exophiala comprises both pathogen species, which cause severe infections in humans, and environmental species, which are able to degrade alkylbenzene compounds. The draft genome sequence of Exophiala mesophila presented here is the first genome assembly of an alkylbenzene-degrading organism belonging to the genus Exophiala.

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Small nucleolar RNAs constitute a significant portion of the eukaryotic small ncRNA transcriptome and guide site-specific methylation or pseudouridylation of target RNAs. In addition, they can play diverse regulatory roles on gene expression, acting as precursors of smaller fragments able to modulate alternative splicing or operate as microRNAs. Defining their expression strategies and the full repertory of their biological functions is a critical, but still ongoing, process in most organisms.

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The fungal genus Cladophialophora comprises many species which cause severe and even fatal infections in humans as well as environmental strains able to degrade polyaromatic hydrocarbons. The draft genome of Cladophialophora immunda presented here is the first whole-genome sequence within this important genus.

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The human genome is scattered with repetitive sequences, and the ENCODE project revealed that 60-70% of the genomic DNA is transcribed into RNA. As a consequence, the human transcriptome contains a large portion of repeat-derived RNAs (repRNAs). Here, we present a hypothesis for the evolution of novel functional repeat-derived RNAs from non-coding RNAs (ncRNAs) by retrotransposition.

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Background: Annotating mammalian genomes for noncoding RNAs (ncRNAs) is nontrivial since far from all ncRNAs are known and the computational models are resource demanding. Currently, the human genome holds the best mammalian ncRNA annotation, a result of numerous efforts by several groups. However, a more direct strategy is desired for the increasing number of sequenced mammalian genomes of which some, such as the pig, are relevant as disease models and production animals.

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The traditional methodology used for the identification of microbes colonizing our cultural heritage was the application of cultivation methods and/or microscopy. This approach has many advantages, as living microorganisms may be obtained for physiological investigations. In addition, these techniques allow the quantitative and qualitative assessment of the investigated environment.

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Bioinformatics of siRNA design.

Methods Mol Biol

November 2014

RNA interference mediated by small interfering RNAs is a powerful tool for investigation of gene functions and is increasingly used as a therapeutic agent. However, not all siRNAs are equally potent, and although simple rules for the selection of good siRNAs were proposed early on, siRNAs are still plagued with widely fluctuating efficiency. Recently, new design tools incorporating both the structural features of the targeted RNAs and the sequence features of the siRNAs substantially improved the efficacy of siRNAs.

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