Early-expressed chemokines predict kidney immunopathology in experimental disseminated Candida albicans infections

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New Clox Systems for rapid and efficient gene disruption in Candida albicans

Acknowledgements: We are grateful to Janet Quinn, Lila Kastora, Joanna Potrykus, Michelle Leach, and others for sharing their experiences with the Clox cassettes. We thank Julia Kohler for her kind gift of the NAT1-flipper plasmid pJK863, Claudia Jacob for her advice with In-fusion cloning, and our colleagues in the Aberdeen Fungal Group for numerous stimulating discussions. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. The sequences of all Clox cassettes are available in GenBank: URA3-Clox (loxP-URA3-MET3p-cre-loxP): GenBank accession number KC999858. NAT1-Clox (loxP-NAT1-MET3p-cre-loxP): GenBank accession number KC999859. LAL (loxP-ARG4-loxP): GenBank accession number DQ015897. LHL (loxP-HIS1-loxP): GenBank accession number DQ015898. LUL (loxP-URA3-loxP): GenBank accession number DQ015899. Funding: This work was supported by the Wellcome Trust (www.wellcome.ac.uk): S.S., F.C.O., N.A.R.G., A.J.P.B. (080088); N.A.R.G., A.J.P.B. (097377). The authors also received support from the European Research Council [http://erc.europa.eu/]: DSC. ERB, AJPB (STRIFE Advanced Grant; C-2009-AdG-249793). The European Commission also provided funding [http://ec.europa.eu/research/fp7]: I.B., A.J.P.B. (FINSysB MC-ITN; PITN-GA-2008-214004). Also the UK Biotechnology and Biological Research Council provided support [www.bbsrc.ac.uk]: N.A.R.G., A.J.P.B. (Research Grant; BB/F00513X/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Property differences among the four major Candida albicans strain clades

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Activation of the heat shock transcription factor Hsf1 is essential for the full virulence of the fungal pathogen Candida albicans

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Glucose Promotes Stress Resistance in the Fungal Pathogen \u3ci\u3eCandida albicans\u3c/i\u3e

Metabolic adaptation, and in particular the modulation of carbon assimilatory pathways during disease progression, is thought to contribute to the pathogenicity of Candida albicans. Therefore, we have examined the global impact of glucose upon the C. albicans transcriptome, testing the sensitivity of this pathogen to wide-ranging glucose levels (0.01, 0.1, and 1.0%). We show that, like Saccharomyces cerevisiae, C. albicans is exquisitely sensitive to glucose, regulating central metabolic genes even in response to 0.01% glucose. This indicates that glucose concentrations in the bloodstream (approximate range 0.05–0.1%) have a significant impact upon C. albicans gene regulation. However, in contrast to S. cerevisiae where glucose down-regulates stress responses, some stress genes were induced by glucose in C. albicans. This was reflected in elevated resistance to oxidative and cationic stresses and resistance to an azole antifungal agent. Cap1 and Hog1 probably mediate glucose-enhanced resistance to oxidative stress, but neither is essential for this effect. However, Hog1 is phosphorylated in response to glucose and is essential for glucose-enhanced resistance to cationic stress. The data suggest that, upon entering the bloodstream, C. albicans cells respond to glucose increasing their resistance to the oxidative and cationic stresses central to the armory of immunoprotective phagocytic cells

Reporters for the analysis of N-glycosylation in \u3ci\u3eCandida albicans\u3c/i\u3e

A large proportion of Candida albicans cell surface proteins are decorated post-translationally by glycosylation. Indeed N-glycosylation is critical for cell wall biogenesis in this major fungal pathogen and for its interactions with host cells. A detailed understanding of N-glycosylation will yield deeper insights into host-pathogen interactions. However, the analysis of N-glycosylation is extremely challenging because of the complexity and heterogeneity of these structures. Therefore, in an attempt to reduce this complexity and facilitate the analysis of N-glycosylation, we have developed new synthetic C. albicans reporters that carry a single N-linked glycosylation site derived from Saccharomyces cerevisiae Suc2. These glycosylation reporters, which carry C. albicans Hex1 or Sap2 signal sequences plus carboxy-terminal FLAG3 and His6 tags, were expressed in C. albicans from the ACT1 promoter. The reporter proteins were successfully secreted and hyperglycosylated by C. albicans cells, and their outer chain glycosylation was dependent on Och1 and Pmr1, which are required for N-mannan synthesis, but not on Mnt1 and Mnt2 which are only required for O-mannosylation. These reporters are useful tools for the experimental dissection of N-glycosylation and other related processes in C. albicans, such as secretion

Glucose Promotes Stress Resistance in the Fungal Pathogen \u3ci\u3eCandida albicans\u3c/i\u3e

Metabolic adaptation, and in particular the modulation of carbon assimilatory pathways during disease progression, is thought to contribute to the pathogenicity of Candida albicans. Therefore, we have examined the global impact of glucose upon the C. albicans transcriptome, testing the sensitivity of this pathogen to wide-ranging glucose levels (0.01, 0.1, and 1.0%). We show that, like Saccharomyces cerevisiae, C. albicans is exquisitely sensitive to glucose, regulating central metabolic genes even in response to 0.01% glucose. This indicates that glucose concentrations in the bloodstream (approximate range 0.05–0.1%) have a significant impact upon C. albicans gene regulation. However, in contrast to S. cerevisiae where glucose down-regulates stress responses, some stress genes were induced by glucose in C. albicans. This was reflected in elevated resistance to oxidative and cationic stresses and resistance to an azole antifungal agent. Cap1 and Hog1 probably mediate glucose-enhanced resistance to oxidative stress, but neither is essential for this effect. However, Hog1 is phosphorylated in response to glucose and is essential for glucose-enhanced resistance to cationic stress. The data suggest that, upon entering the bloodstream, C. albicans cells respond to glucose increasing their resistance to the oxidative and cationic stresses central to the armory of immunoprotective phagocytic cells

One year prospective survey of Candida bloodstream infections in Scotland

A 12 month survey of candidaemia in Scotland, UK, in which every Scottish hospital laboratory submitted all blood isolates of yeasts for identification, strain typing and susceptibility testing, provided 300 isolates from 242 patients, generating incidence data of 4.8 cases per 100 000 population per year and 5.9 cases per 100 000 acute occupied bed days; 27.9 % of cases occurred in intensive care units. More than half the patients with candidaemia had an underlying disease involving the abdomen, 78 % had an indwelling intravenous catheter, 62 % had suffered a bacterial infection within the 2 weeks prior to candidaemia and 37 % had undergone a laparotomy. Candida albicans was the infecting species in 50 % of cases, followed by Candida glabrata (21 %) and Candida parapsilosis (12 %). Seven cases of candidaemia were caused by Candida dubliniensis, which was more prevalent even than Candida lusitaniae and Candida tropicalis (six cases each). Among C. glabrata isolates, 55 % showed reduced susceptibility to fluconazole, but azole resistance among other species was extremely low. Multilocus sequence typing showed isolates with high similarity came from different hospitals across the country, and many different types came from the hospitals that submitted the most isolates, indicating no tendency towards hospital-specific endemic strains. Multiple isolates of C. albicans and C. glabrata from individual patients were of the same strain type with single exceptions for each species. The high prevalence of candidaemia in Scotland, relative to other population-based European studies, and the high level of reduced fluconazole susceptibility of Scottish C. glabrata isolates warrant continued future surveillance of invasive Candida infections