Robust extracellular pH modulation by Candida albicans during growth in carboxylic acids
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ABSTRACT: Purpose: Candida albicans avidly uses multiple carbon sources that are less preferred by related species. This project compared transcriptional profiles of cells growing in media containing these nutrients relative to glucose Methods: C. albicans strain SC5314 was incubated in minimal YNB media containing 2% glucose, casamino acids, glutamate or a-ketoglutarate for five hours. RNA was prepared and subjected to deep sequencing. Results: Substantial overlap was seen in the transcriptional changes in all alternative carbon sources relative to the glucose control. Source-specific changes reflected the unique metabolism of each nutrient. Conclusions: C. albicans is well-adapted to use a range of nutrients that can be found in the mammalian host and has a common transcriptional response to limiting carbon environments.
Project description:Experiment Description RNA sequencing was performed on Candida albicans wild type cells (SC5314) grown to exponential phase on YNB Lactate, YNB Glucose, or YNB Glucose plus Lactate, and compared to exponential Candida albicans crz1 cells grown on YNB Glucose or YNB Glucose plus Lactate. Three independent experiments were performed.
Project description:Goal of this study was to investigate the metabolic adaptation of C. albicans to different carbon sources (malic acid, α-ketoglutarate, proline) and nitrogen sources (dipeptides). As a control medium with glucose as carbon source and ammonium sulfate as nitrogen source was used. Transcriptional profiles were compared after 4 h incubation at 37°C.
Project description:Candida albicans is an opportunist pathogen responsible for a large spectrum of infections, from superficial mycosis to systemic diseases known as candidiasis. C. albicans can grow in various morphological forms, including unicellular budding yeasts, filamentous pseudophyphae and true hyphae, and the ability to switch from yeast to hyphal forms is a key survival mechanism in the adaptation of the pathogen to the microenvironments encountered within the host. The filamentation is regulated by multiple signalling pathways and can be induced, in vitro, in several growth media, often leading to contradictory results in the literature. In this study, we use quantitative proteomic analyses to compare the response of C. albicans yeast cells grown in the minimal medium YNB to four media widely used in the literature to induce the yeast to hyphae transition: YNB-Serum, YNB-N-Acetyl-glucosamine (YNB-NAG), Lee medium and the rich Spider medium. We show here that each growth medium induces a unique pattern of response in C. albicans cells, and that some conditions trigger an original and specific metabolic adaptive response. Moreover, comparison of the proteomic profiles indicates modifications of the thiol-dependent oxidative stress status of the cells, especially in YNB-Serum and Lee medium, and, to a lesser extent, in Spider medium, confirming the role of oxidative stress in the filamentation process. Overall, our data indicate that some hypha-inducing media routinely used in the literature are associated with significant changes in in proteomic signature and that should be more often taken account when exploring the filamentation process of the pathogen.
Project description:Transcriptional profiling of Candida parapsilosis in media with a preferred nitrogen source (ammonium sulfate) and a non-preferred source (isoleucine) to identify genes that are subject to Nitrogen Catabolite Expression. Gene expression of wild type and dal81 deletion strains were compared during growth in complex nitrogen sources (YPD), in minimal media with a preferred nitrogen source (YNB+ammonium sulfate) and minimal medium with a non-preferred source (GABA).
Project description:This experiment was designed to test the change in gene expression in the absence of the transcription factor, CreA. Two media conditions were tested to determine the role of this transcription factor in repressing (glucose) and derepressing (ethanol) carbon sources.
Project description:Sak1 (orf19.3840) of Candida albicans was found to be a kinase which phosphorylates and thereby activates Snf1, a highly conserved regulator of nutrient stress responses. Accordingly, a sak1 deletion mutant failed to grow on many alternative (i.e., non-glucose) carbon sources, but also showed a filamentation defect upon growth under glucose limitation and exhibited reduced virulence. To better define the effects of Sak1 on C. albicans metabolic adaptations, these transcriptional analyses were performed in complex medium, using a sak1 deletion mutant in comparison to the wild type.
Project description:We transcriptional profiled four transcription factor knockout strains in S288C background growing in YNB media + 2% glucose to understand the link between mRNA levels and our measured C13 fluxes of amino acid biosynthesis. We conducted this analysis as a follow up to our work on the Gcn4p transcription factor. Keywords: genetic modification
Project description:Pathogenic Candida fungi are a leading cause of opportunistic, hospital-associated bloodstream infections with high mortality rates, typically in immunocompromised patients. Several species, including C. albicans, the most prevalent cause of infection, belong to the monophyletic CUG clade of yeasts. Much is known about the interaction of C. albicans with innate immune cells, which are crucial for controlling infection. Phagocytosis of C. albicans elicits transcriptional induction of several pathways involved in catabolism of non-glucose carbon sources that are important for virulence, termed alternative carbon metabolism. However, the response of other CUG clade species has not been characterized. In a separate dataset, we profiled transcriptional responses to primary murine bone marrow derived macrophages in six Candida species. Here we additionally profiled the response of M. guilliermondii, a yeast that is known as a cause of disseminated candidiasis as well as cutaneous infections. We find that similar to other CUG-clade Candida species, it mounts a robust alternative carbon metabolism response to phagocytosis.
Project description:Purpose: To investigate the influence of the 40 genes on plasmid, we compared the transcript varies between the engineered strains and the wild-type strain in synthetic medium with different carbon sources (i.e., glucose, galactose and ethanol/glycerol media). Methods: Total mRNA profiles of the engineered strains and the wild-type strain were generated by deep sequencing, in triplicate, using BGIseq500. The sequence reads that passed quality filters were analyzed. Results: RNA sequencing results revealed that the transcript patterns were influenced dramatically by the carbon sources and there was no significant difference between the wild-type and engineered strains (that is, any change amounted to less than 10%)
Project description:We propose a carbon source dependent genetic regulatory network for the budding yeast Saccharomyces cerevisiae, derived from quantitative proteomic analyses integrated with bioinformatics knowledge of regulatory pathways and protein interactions. The proposed network, comprising 1247 transcription factor interactions and 126 chaperone interactions, defines the proteome shift in the cell when growing under different carbon sources. We used a label-free proteomics strategy to quantify alterations in protein abundance for S. cerevisiae when grown on minimal media using glucose, galactose, maltose and trehalose as sole carbon sources.