scholarly journals Plasmids for in vivo construction of integrative Candida albicans vectors in Saccharomyces cerevisiae

Yeast ◽  
2010 ◽  
Vol 27 (11) ◽  
pp. 933-939 ◽  
Author(s):  
Neide Vieira ◽  
Filipa Pereira ◽  
Margarida Casal ◽  
Alistair J. P. Brown ◽  
Sandra Paiva ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans

scholarly journals Divergent Subunit Interactions among Fungal mRNA 5′-Capping Machineries

2002 ◽  
Vol 1 (3) ◽  
pp. 448-457 ◽  
Author(s):  
Toshimitsu Takagi ◽  
Eun-Jung Cho ◽  
Rozmin T. K. Janoo ◽  
Vladimir Polodny ◽  
Yasutaka Takase ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Rna Polymerase Ii ◽  
Subunit Interactions ◽  
Pol Ii ◽  
Mrna Capping ◽  
Capping Enzyme ◽  
Enzyme Subunits ◽  
Carboxyl Terminal

ABSTRACT The Saccharomyces cerevisiae mRNA capping enzyme consists of two subunits: an RNA 5′-triphosphatase (RTPase) and GTP::mRNA guanylyltransferase (GTase). The GTase subunit (Ceg1) binds to the phosphorylated carboxyl-terminal domain of the largest subunit (CTD-P) of RNA polymerase II (pol II), coupling capping with transcription. Ceg1 bound to the CTD-P is inactive unless allosterically activated by interaction with the RTPase subunit (Cet1). For purposes of comparison, we characterize here the related GTases and RTPases from the yeasts Schizosaccharomyces pombe and Candida albicans. Surprisingly, the S. pombe capping enzyme subunits do not interact with each other. Both can independently interact with CTD-P of pol II, and the GTase is not repressed by CTD-P binding. The S. pombe RTPase gene (pct1 +) is essential for viability. Pct1 can replace the S. cerevisiae RTPase when GTase activity is supplied by the S. pombe or mouse enzymes but not by the S. cerevisiae GTase. The C. albicans capping enzyme subunits do interact with each other. However, this interaction is not essential in vivo. Our results reveal an unexpected diversity among the fungal capping machineries.

scholarly journals Toll-Like Receptor 9 Modulates Macrophage Antifungal Effector Function during Innate Recognition of Candida albicans and Saccharomyces cerevisiae

2011 ◽  
Vol 79 (12) ◽  
pp. 4858-4867 ◽  
Author(s):  
Pia V. Kasperkovitz ◽  
Nida S. Khan ◽  
Jenny M. Tam ◽  
Michael K. Mansour ◽  
Peter J. Davids ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Fungal Pathogens ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Tnf Α ◽  
Tlr9 Gene

ABSTRACTPhagocytic responses are critical for effective host defense against opportunistic fungal pathogens. Macrophages sample the phagosomal content and orchestrate the innate immune response. Toll-like receptor 9 (TLR9) recognizes unmethylated CpG DNA and is activated by fungal DNA. Here we demonstrate that specific triggering of TLR9 recruitment to the macrophage phagosomal membrane is a conserved feature of fungi of distinct phylogenetic origins, includingCandida albicans,Saccharomyces cerevisiae,Malassezia furfur, andCryptococcus neoformans. The capacity to trigger phagosomal TLR9 recruitment was not affected by a loss of fungal viability or cell wall integrity. TLR9 deficiency has been linked to increased resistance to murine candidiasis and to restriction of fungal growthin vivo. Macrophages lacking TLR9 demonstrate a comparable capacity for phagocytosis and normal phagosomal maturation compared to wild-type macrophages. We now show that TLR9 deficiency increases macrophage tumor necrosis factor alpha (TNF-α) production in response toC. albicansandS. cerevisiae, independent of yeast viability. The increase in TNF-α production was reversible by functional complementation of the TLR9 gene, confirming that TLR9 was responsible for negative modulation of the cytokine response. Consistently, TLR9 deficiency enhanced the macrophage effector response by increasing macrophage nitric oxide production. Moreover, microbicidal activity againstC. albicansandS. cerevisiaewas more efficient in TLR9 knockout (TLR9KO) macrophages than in wild-type macrophages. In conclusion, our data demonstrate that TLR9 is compartmentalized selectively to fungal phagosomes and negatively modulates macrophage antifungal effector functions. Our data support a model in which orchestration of antifungal innate immunity involves a complex interplay of fungal ligand combinations, host cell machinery rearrangements, and TLR cooperation and antagonism.

scholarly journals Cytocidal amino acid starvation of Saccharomyces cerevisiae and Candida albicans acetolactate synthase (ilv2Δ) mutants is influenced by the carbon source and rapamycin

Microbiology ◽  
2010 ◽  
Vol 156 (3) ◽  
pp. 929-939 ◽  
Author(s):  
Joanne M. Kingsbury ◽  
John H. McCusker
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Carbon Source ◽  
Drug Target ◽  
Acetolactate Synthase ◽  
Antifungal Drug ◽  
Tor Pathway ◽  
Fold Reduction ◽  
Isoleucine Biosynthesis

The isoleucine and valine biosynthetic enzyme acetolactate synthase (Ilv2p) is an attractive antifungal drug target, since the isoleucine and valine biosynthetic pathway is not present in mammals, Saccharomyces cerevisiae ilv2Δ mutants do not survive in vivo, Cryptococcus neoformans ilv2 mutants are avirulent, and both S. cerevisiae and Cr. neoformans ilv2 mutants die upon isoleucine and valine starvation. To further explore the potential of Ilv2p as an antifungal drug target, we disrupted Candida albicans ILV2, and demonstrated that Ca. albicans ilv2Δ mutants were significantly attenuated in virulence, and were also profoundly starvation-cidal, with a greater than 100-fold reduction in viability after only 4 h of isoleucine and valine starvation. As fungicidal starvation would be advantageous for drug design, we explored the basis of the starvation-cidal phenotype in both S. cerevisiae and Ca. albicans ilv2Δ mutants. Since the mutation of ILV1, required for the first step of isoleucine biosynthesis, did not suppress the ilv2Δ starvation-cidal defects in either species, the cidal phenotype was not due to α-ketobutyrate accumulation. We found that starvation for isoleucine alone was more deleterious in Ca. albicans than in S. cerevisiae, and starvation for valine was more deleterious than for isoleucine in both species. Interestingly, while the target of rapamycin (TOR) pathway inhibitor rapamycin further reduced S. cerevisiae ilv2Δ starvation viability, it increased Ca. albicans ilv1Δ and ilv2Δ viability. Furthermore, the recovery from starvation was dependent on the carbon source present during recovery for S. cerevisiae ilv2Δ mutants, reminiscent of isoleucine and valine starvation inducing a viable but non-culturable-like state in this species, while Ca. albicans ilv1Δ and ilv2Δ viability was influenced by the carbon source present during starvation, supporting a role for glucose wasting in the Ca. albicans cidal phenotype.

scholarly journals Spt3 Plays Opposite Roles in Filamentous Growth in Saccharomyces cerevisiae and Candida albicans and Is Required for C. albicans Virulence

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 509-519
Author(s):  
Lisa Laprade ◽  
Victor L Boyartchuk ◽  
William F Dietrich ◽  
Fred Winston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Filamentous Growth ◽  
Growth Defect ◽  
Invasive Growth ◽  
Pathogenic Yeast ◽  
Normal Expression

Abstract Spt3 of Saccharomyces cerevisiae is required for the normal transcription of many genes in vivo. Past studies have shown that Spt3 is required for both mating and sporulation, two events that initiate when cells are at G1/START. We now show that Spt3 is needed for two other events that begin at G1/START, diploid filamentous growth and haploid invasive growth. In addition, Spt3 is required for normal expression of FLO11, a gene required for filamentous growth, although this defect is not the sole cause of the spt3Δ/spt3Δ filamentous growth defect. To extend our studies of Spt3's role in filamentous growth to the pathogenic yeast Candida albicans, we have identified the C. albicans SPT3 gene and have studied its role in C. albicans filamentous growth and virulence. Surprisingly, C. albicans spt3Δ/spt3Δ mutants are hyperfilamentous, the opposite phenotype observed for S. cerevisiae spt3Δ/spt3Δ mutants. Furthermore, C. albicans spt3Δ/spt3Δ mutants are avirulent in mice. These experiments demonstrate that Spt3 plays important but opposite roles in filamentous growth in S. cerevisiae and C. albicans.

scholarly journals Functional expression, quantification and cellular localization of the Hxt2 hexose transporter of Saccharomyces cerevisiae tagged with the green fluorescent protein

1999 ◽  
Vol 339 (2) ◽  
pp. 299-307 ◽  
Author(s):  
Arthur L. KRUCKEBERG ◽  
Ling YE ◽  
Jan A. BERDEN ◽  
Karel van DAM
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Green Fluorescent Protein ◽  
Glucose Transport ◽  
Cellular Localization ◽  
Fluorescent Protein ◽  
Hexose Transporter ◽  
High Concentrations ◽  
Green Fluorescent

The Hxt2 glucose transport protein of Saccharomyces cerevisiae was genetically fused at its C-terminus with the green fluorescent protein (GFP). The Hxt2-GFP fusion protein is a functional hexose transporter: it restored growth on glucose to a strain bearing null mutations in the hexose transporter genes GAL2 and HXT1 to HXT7. Furthermore, its glucose transport activity in this null strain was not markedly different from that of the wild-type Hxt2 protein. We calculated from the fluorescence level and transport kinetics that induced cells had 1.4×105 Hxt2-GFP molecules per cell, and that the catalytic-centre activity of the Hxt2-GFP molecule in vivo is 53 s-1 at 30 °C. Expression of Hxt2-GFP was induced by growth at low concentrations of glucose. Under inducing conditions the Hxt2-GFP fluorescence was localized to the plasma membrane. In a strain impaired in the fusion of secretory vesicles with the plasma membrane, the fluorescence accumulated in the cytoplasm. When induced cells were treated with high concentrations of glucose, the fluorescence was redistributed to the vacuole within 4 h. When endocytosis was genetically blocked, the fluorescence remained in the plasma membrane after treatment with high concentrations of glucose.

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