Project description:We analyzed gene expression in the American black bear, Ursus americanus, using a custom 12,800 cDNA probe (BA02) microarray to detect differences in expression that occur in heart and liver during winter hibernation in comparison to summer active animals. We identified 245 genes in heart and 319 genes in liver that were differentially expressed between winter and summer. The expression of 24 genes was significantly elevated during hibernation in both heart and liver. These genes are mostly involved in lipid catabolism and protein biosynthesis and include RNA binding protein motif 3 (Rbm3), which enhances protein synthesis at mildly hypothermic temperatures. Elevated expression of protein biosynthesis genes suggests induction of translation that may be related to adaptive mechanisms reducing cardiac and muscle atrophies over extended periods of low metabolism and immobility during hibernation in bears. Coordinated reduction of transcription of genes involved in amino acid catabolism suggests redirection of amino acids from catabolic pathways to protein biosynthesis. We identify common for black bears and small mammalian hibernators transcriptional changes in the liver that include induction of genes responsible for fatty acid β oxidation and carbohydrate synthesis and depression of genes involved in lipid biosynthesis, carbohydrate catabolism, cellular respiration and detoxification pathways. Our findings show that modulation of gene expression during winter hibernation represents molecular mechanism of adaptation to extreme environments. Black bears sampled during winter hibernation were compared with the animals sampled during summer. Two tissue types, liver and heart, were hybridized on a custom 12,800 cDNA probe nylon membrane microarray platform . Six hibernating and five summer active bears were studied in experiments with liver tissue, six hibernating and five summer active animals were tested with heart tissue.
Project description:We analyzed gene expression in the American black bear, Ursus americanus, using a custom 12,800 cDNA probe (BA02) microarray to detect differences in expression that occur in heart and liver during winter hibernation in comparison to summer active animals. We identified 245 genes in heart and 319 genes in liver that were differentially expressed between winter and summer. The expression of 24 genes was significantly elevated during hibernation in both heart and liver. These genes are mostly involved in lipid catabolism and protein biosynthesis and include RNA binding protein motif 3 (Rbm3), which enhances protein synthesis at mildly hypothermic temperatures. Elevated expression of protein biosynthesis genes suggests induction of translation that may be related to adaptive mechanisms reducing cardiac and muscle atrophies over extended periods of low metabolism and immobility during hibernation in bears. Coordinated reduction of transcription of genes involved in amino acid catabolism suggests redirection of amino acids from catabolic pathways to protein biosynthesis. We identify common for black bears and small mammalian hibernators transcriptional changes in the liver that include induction of genes responsible for fatty acid β oxidation and carbohydrate synthesis and depression of genes involved in lipid biosynthesis, carbohydrate catabolism, cellular respiration and detoxification pathways. Our findings show that modulation of gene expression during winter hibernation represents molecular mechanism of adaptation to extreme environments.
Project description:The class Dothideomycetes (along with Eurotiomycetes) includes numerous rock-inhabiting fungi (RIF), a group of ascomycetes that tolerates surprisingly well harsh conditions prevailing on rock surfaces. Despite their convergent morphology and physiology, RIF are phylogenetically highly diverse in Dothideomycetes. However, the positions of main groups of RIF in this class remain unclear due to the lack of a strong phylogenetic framework. Moreover, connections between rock-dwelling habit and other lifestyles found in Dothideomycetes such as plant pathogens, saprobes and lichen-forming fungi are still unexplored. Based on multigene phylogenetic analyses, we report that RIF belong to Capnodiales (particularly to the family Teratosphaeriaceae s.l.), Dothideales, Pleosporales, and Myriangiales, as well as some uncharacterised groups with affinities to Dothideomycetes. Moreover, one lineage consisting exclusively of RIF proved to be closely related to Arthoniomycetes, the sister class of Dothideomycetes. The broad phylogenetic amplitude of RIF in Dothideomycetes suggests that total species richness in this class remains underestimated. Composition of some RIF-rich lineages suggests that rock surfaces are reservoirs for plant-associated fungi or saprobes, although other data also agree with rocks as a primary substrate for ancient fungal lineages. According to the current sampling, long distance dispersal seems to be common for RIF. Dothideomycetes lineages comprising lichens also include RIF, suggesting a possible link between rock-dwelling habit and lichenisation.
Project description:We analyzed oxidized 5-methylcytosine derivatives 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine in nucleic acids of multicellular fungi Laccaria bicolor and Coprinopsis cinerea which have been used as models to study DNA methylation, developmental processes and symbiotic interactions. All three cytosine derivatives were detected in the genomes of both fungi, and importantly, we discovered 5carC in the RNA fractions, potentially including large non-coding, messenger RNAs and small RNA molecules, indicating gene regulatory functions of 5carC.
Project description:Ergosterol, a pivotal constituent of the fungal cell membrane, plays a crucial role in diverse cellular activities. Fungi inherently regulate ergosterol homeostasis, a process traditionally associated with the control of a major transcription factor, like SREBP, activated in response to ergosterol depletion, regardless of which ergosterol biosynthesis step is affected. Contrary to the established paradigm, our investigation demonstrates that the inhibition of ergosterol biosynthesis at specific steps triggers distinct transcriptional responses in erg genes across fungi, including Neurospora crassa, Aspergillus fumigatus, and Fusarium verticillioides. In N. crassa, the targeted responses are orchestrated by several transcription factors that have undergone functional rewiring. Specifically, ERG24 inhibition by amorolfine activates transcription factors SAH-2 and AtrR, resulting in the upregulation of erg24, erg2, erg25 and erg3. Additionally, ERG11 inhibition by azoles activates transcription factor NcSR, leading to the upregulation of erg11 and erg6. Our findings unveil a novel sophisticated regulation model of sterol biosynthesis in fungi which potentially enhances fungal survival in complex environments, thus providing new insights into sterol homeostasis maintenance and a deeper understanding of drug resistance mechanisms in fungi.