Project description:Microarray experiments were performed to reveal the key genes involved in iron homeostasis in the pathogenic yeast Candida glabrata.
Project description:The pathogenic yeast species Candida glabrata has an intrinsically high resilience to azoles and a rapid capability of acquiring resistance. Azole-resistant clinical strains derive mostly from them encoding hyperactive mutants of the CgPdr1 regulator, however, strains encoding wild-type CgPdr1 variants were identified suggesting a role for CgPdr1-independent mechanisms in acquisition of resistance in vivo. Seven azole-resistant C. glabrata isolates were found to encode CgPdr1 gain-of-function variants, two, I392M and I803T, being herein described for the first time. OMICS profile of the sole azole-resistant strain encoding a wild-type CgPDR1 allele revealed that these cells over-express several genes described for providing protection against azoles, while down-regulating genes described to increase sensitivity to these drugs. Over-expression of genes required for metabolism and transport of sterols to compensate the azole-induced inhibition of Erg11 and a more active calcineurin pathway are other mechanisms suggested to underlie azole resistance in ISTB218.
Project description:Candida glabrata is a human-associated opportunistic fungal pathogen. It shares its niche with Lactobacillus spp. in the gastrointestinal and vaginal tract. In fact, Lactobacillus species are thought to competitively prevent Candida overgrowth. We investigated the molecular aspects of this antifungal effect by analyzing the interaction of C. glabrata strains with Limosilactobacillus fermentum. From a collection of clinical C. glabrata isolates, we identified strains with different sensitivities to L. fermentum in coculture. We analyzed the variation of their expression pattern to isolate the specific response to L. fermentum. C. glabrata-L. fermentum coculture induced genes associated with ergosterol biosynthesis, weak acid stress, and drug/chemical stress. L. fermentum coculture depleted C. glabrata ergosterol. The reduction of ergosterol was dependent on the Lactobacillus species, even in coculture with different Candida species. We found a similar ergosterol-depleting effect with other lactobacillus strains (Lactobacillus crispatus and Lactobacillus rhamosus) on Candida albicans, Candida tropicalis, and Candida krusei. The addition of ergosterol improved C. glabrata growth in the coculture. Blocking ergosterol synthesis with fluconazole increased the susceptibility against L. fermentum, which was again mitigated by the addition of ergosterol. In accordance, a C. glabrata Derg11 mutant, defective in ergosterol biosynthesis, was highly sensitive to L. fermentum. In conclusion, our analysis indicates an unexpected direct function of ergosterol for C. glabrata proliferation in coculture with L. fermentum.
Project description:The objective of the project is to identify proteins that interact with CgHog1 under low-iron, regular-iron and high-iron growth conditions in the pathogenic yeast Candida glabrata.
Project description:The objective of the project is to identify CgSub2-interacting proteins in the presence and absence of CgHog1 MAPK in the pathogenic yeast Candida glabrata, with CgSub2 being an interactor of CgHog1.
Project description:In these experiments, we compared the transcriptomes of a wild type strain and an aft2 deleted strain of the pathogenic yeast Candida glabrata. The comparisons were performed in four different growth conditions: iron starvation (BPS treatment), selenite treatment, cadmium treatment and optimal growth conditions (YPD).
Project description:The yeast Candida glabrata is one of the most important human fungal pathogens and has emerged as a leading cause of nosocomial bloodstream infections. Its resistance to many routinely used antimycotics and its close relationship to the model organism Saccharomyces cerevisiae make this fungus an interesting target of biomedical research. Although the genome sequence was published a decade ago, little is known about the transcriptional dynamics within this pathogen, especially compared to other pathogenic and nonpathogenic yeasts.We provide a detailed RNA-Seq-based analysis of the transcriptomic landscape of C. glabrata in nutrient-rich media as well as under stress conditions and weak acidic and alkaline environments. Using state of the art bioinformatics tools, we were able to refine the annotation of the C. glabrata genome up to 5288 transcriptional active protein-coding ORFs. Introns were identified in 175 of these genes. Based on our data we were able to increase the number of noncoding RNAs to 68. Additionally, we could detect the expression of 50 novel ORFs. This comprehensive analysis of C. glabrataM-bM-^@M-^Ys transcriptomic landscape significantly enhances the annotation of current genome annotation and contributes to a further understanding of the molecular mechanisms of the pathogenicity of this medical important yeast. Candida glabrata was grown in standard nutrient-rich medium(wt_37), ph4(wt_pH4), ph8(w,_pH8) and in nitrosative stress (GSNO) conditions(wt_GSNO). After harvesting RNA, paired-end and strand-specific RNA-Seq was performed on three biological replicates after PolyA filtering respectively. Additionally, a fourth replicate without filtering was sequenced single-end and not strand-specific..
Project description:Eukaryotic transcription activators stimulate the expression of specific sets of target genes through recruitment of co-activators such as the RNA polymerase II-interacting Mediator complex. We previously identified an activator-targeted ~85 amino acid three-helix bundle KIX domain in the human MED15 Mediator subunit that is structurally conserved in Gal11 Mediator subunits in fungi. The Gal11 KIX domain is engaged by pleiotropic drug resistance transcription factor (Pdr1) orthologues, key regulators of the multidrug resistance (MDR) pathway in S. cerevisiae and in the clinically important human pathogen Candida glabrata. Drug-resistant clinical isolates of C. glabrata most commonly harbour point mutations in Pdr1 that render it constitutively active, suggesting that this transcriptional activation pathway may represent a lynchpin in C. glabrata MDR. We have now carried out sequential biochemical and in vivo high-throughput screens to identify small molecule inhibitors of the interaction of the C. glabrata Pdr1 activation domain with the C. glabrata Gal11A KIX domain. The lead compound (iKIX1) inhibits Pdr1-dependent gene activation in both S. cerevisiae and C. glabrata and re-sensitizes drug-resistant C. glabrata to effective azole antifungal concentrations in vitro and in animal models for disseminated and urinary tract C. glabrata infection. Samples are generated in triplicate for four conditions (DMSO/vehicle-treated, iKIX1-treated, DMSO/vehicle and ketoconazole-treated. and iKIX1-ketoconazole treated) in both Saccharomyces cerevisiae and Candida glabrata
Project description:<p><em>Candida</em> species are the most common cause of opportunistic fungal infections. Rapid identification and novel approaches for the characterization of these fungi are of great interest to improve the diagnosis and the knowledge about their pathogenic properties. This study aimed to characterize clinical isolates of <em>Candida</em> spp. by proteomics (MALDI-TOF MS) and metabolomics (<sup>1</sup>H-NMR), and to correlate their metabolic profiles with <em>Candida</em> species, source of infection and different virulence associated parameters. In particular, 49 <em>Candida</em> strains from different sources (blood, n = 15; vagina, n = 18; respiratory tract, n = 16), belonging mainly to <em>C. albicans</em> complex (61%), <em>C. glabrata</em> (20%) and <em>C. parapsilosis</em> (12%) species were used. Several extracellular and intracellular metabolites showed significantly different concentrations among isolates recovered from different sources of infection, as well as among different <em>Candida</em> species. These metabolites were mainly related to the glycolysis or gluconeogenesis, tricarboxylic acid cycle, nucleic acid synthesis and amino acid and lipid metabolism. Moreover, we found specific metabolic fingerprints associated with the ability to form biofilm, the antifungal resistance (i.e. caspofungin and fluconazole) and the production of secreted aspartyl proteinase. In conclusion, <sup>1</sup>H-NMR-based metabolomics can be useful to deepen <em>Candida</em> spp. virulence and pathogenicity properties.</p>