103 COMPARATIVE VIRULENCE OF CANDIDA ALBICANS AND CANDIDA PARAPSILOSIS IN A MOUSE MODEL OF SYSTEMIC INFECTION.

2006 ◽  
Vol 54 (1) ◽  
pp. S97.3-S97
Author(s):  
M. A. Johnson ◽  
R. M. Garni ◽  
C. L. Wells ◽  
C. M. Bendel
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Candida Parapsilosis ◽  
Systemic Infection

scholarly journals Candida albicans Uses Multiple Mechanisms To Acquire the Essential Metabolite Inositol during Infection

2008 ◽  
Vol 76 (6) ◽  
pp. 2793-2801 ◽  
Author(s):  
Ying-Lien Chen ◽  
Sarah Kauffman ◽  
Todd B. Reynolds
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Double Mutant ◽  
De Novo ◽  
Systemic Infection ◽  
Bloodstream Infections ◽  
Wild Type Allele ◽  
Transporter Gene ◽  
Wild Type ◽  
Life Threatening

ABSTRACT Candida albicans is an important cause of life-threatening systemic bloodstream infections in immunocompromised patients. In order to cause infections, C. albicans must be able to synthesize the essential metabolite inositol or acquire it from the host. Based on the similarity of C. albicans to Saccharomyces cerevisiae, it was predicted that C. albicans may generate inositol de novo, import it from the environment, or both. The C. albicans inositol synthesis gene INO1 (orf19.7585) and inositol transporter gene ITR1 (orf19.3526) were each disrupted. The ino1Δ/ino1Δ mutant was an inositol auxotroph, and the itr1Δ/itr1Δ mutant was unable to import inositol from the medium. Each of these mutants was fully virulent in a mouse model of systemic infection. It was not possible to generate an ino1Δ/ino1Δ itr1Δ/itr1Δ double mutant, suggesting that in the absence of these two genes, C. albicans could not acquire inositol and was nonviable. A conditional double mutant was created by replacing the remaining wild-type allele of ITR1 in an ino1Δ/ino1Δ itr1Δ/ITR1 strain with a conditionally expressed allele of ITR1 driven by the repressible MET3 promoter. The resulting ino1Δ/ino1Δ itr1Δ/PMET3 ::ITR1 strain was found to be nonviable in medium containing methionine and cysteine (which represses the PMET3 promoter), and it was avirulent in the mouse model of systemic candidiasis. These results suggest a model in which C. albicans has two equally effective mechanisms for obtaining inositol while in the host. It can either generate inositol de novo through Ino1p, or it can import it from the host through Itr1p.

scholarly journals Combined Inactivation of the Candida albicans GPR1 and TPS2 Genes Results in Avirulence in a Mouse Model for Systemic Infection

2008 ◽  
Vol 76 (4) ◽  
pp. 1686-1694 ◽  
Author(s):  
Mykola M. Maidan ◽  
Larissa De Rop ◽  
Miguel Relloso ◽  
Rosalia Diez-Orejas ◽  
Johan M. Thevelein ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Double Mutant ◽  
Systemic Infection ◽  
Antifungal Drugs ◽  
The Other ◽  
Growth Defect ◽  
Other Hand ◽  
Solid Media

ABSTRACT Inhibition of the biosynthesis of trehalose, a well-known stress protectant in pathogens, is an interesting approach for antifungal or antibacterial therapy. Deletion of TPS2, encoding trehalose-6-phosphate (T6P) phosphatase, results in strongly reduced virulence of Candida albicans due to accumulation of T6P instead of trehalose in response to stress. To further aggravate the deregulation in the pathogen, we have additionally deleted the GPR1 gene, encoding the nutrient receptor that activates the cyclic AMP-protein kinase A signaling pathway, which negatively regulates trehalose accumulation in yeasts. A gpr1 mutant is strongly affected in morphogenesis on solid media as well as in vivo in a mouse model but has only a slightly decreased virulence. The gpr1 tps2 double mutant, on the other hand, is completely avirulent in a mouse model for systemic infection. This strain accumulates very high T6P levels under stress conditions and has a growth defect at higher temperatures. We also show that a tps2 mutant is more sensitive to being killed by macrophages than the wild type or the gpr1 mutant. A double mutant has susceptibility similar to that of the single tps2 mutant. For morphogenesis on solid media, on the other hand, the gpr1 tps2 mutant shows a phenotype similar to that of the single gpr1 mutant. Taken together these results show that there is synergism between Gpr1 and Tps2 and that their combined inactivation results in complete avirulence. Combination therapy targeting both proteins may prove highly effective against pathogenic fungi with increased resistance to the currently used antifungal drugs.

scholarly journals Rapid proliferation due to better metabolic adaptation results in full virulence of a filament-deficient Candida albicans strain

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christine Dunker ◽  
Melanie Polke ◽  
Bianca Schulze-Richter ◽  
Katja Schubert ◽  
Sven Rudolphi ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Systemic Infection ◽  
Hyphal Growth ◽  
Metabolic Adaptation ◽  
Infection Model ◽  
Intraperitoneal Infection ◽  
Systemic Infections

AbstractThe ability of the fungal pathogen Candida albicans to undergo a yeast-to-hypha transition is believed to be a key virulence factor, as filaments mediate tissue damage. Here, we show that virulence is not necessarily reduced in filament-deficient strains, and the results depend on the infection model used. We generate a filament-deficient strain by deletion or repression of EED1 (known to be required for maintenance of hyphal growth). Consistent with previous studies, the strain is attenuated in damaging epithelial cells and macrophages in vitro and in a mouse model of intraperitoneal infection. However, in a mouse model of systemic infection, the strain is as virulent as the wild type when mice are challenged with intermediate infectious doses, and even more virulent when using low infectious doses. Retained virulence is associated with rapid yeast proliferation, likely the result of metabolic adaptation and improved fitness, leading to high organ fungal loads. Analyses of cytokine responses in vitro and in vivo, as well as systemic infections in immunosuppressed mice, suggest that differences in immunopathology contribute to some extent to retained virulence of the filament-deficient mutant. Our findings challenge the long-standing hypothesis that hyphae are essential for pathogenesis of systemic candidiasis by C. albicans.

scholarly journals Unaltered Fungal Burden and Lethality in Human CEACAM1-Transgenic Mice During Candida albicans Dissemination and Systemic Infection

2019 ◽  
Vol 10 ◽  
Author(s):  
Esther Klaile ◽  
Mario M. Müller ◽  
Cristina Zubiría-Barrera ◽  
Saskia Brehme ◽  
Tilman E. Klassert ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Transgenic Mice ◽  
Systemic Infection ◽  
Fungal Burden

scholarly journals Identification and Characterization of TUP1-Regulated Genes in Candida albicans

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Burkhard R Braun ◽  
W Steven Head ◽  
Ming X Wang ◽  
Alexander D Johnson
Keyword(s):  
Candida Albicans ◽  
Systemic Infection ◽  
Subtractive Hybridization ◽  
Filamentous Growth ◽  
Surface Proteins ◽  
Infection Model ◽  
Ferric Reductase ◽  
Pathogenesis Related Protein ◽  
Plant Pathogenesis ◽  
Rnase T2

Abstract TUP1 encodes a transcriptional repressor that negatively controls filamentous growth in Candida albicans. Using subtractive hybridization, we identified six genes, termed repressed by TUP1 (RBT), whose expression is regulated by TUP1. One of the genes (HWP1) has previously been characterized, and a seventh TUP1-repressed gene (WAP1) was recovered due to its high similarity to RBT5. These genes all encode secreted or cell surface proteins, and four out of the seven (HWP1, RBT1, RBT5, and WAP1) encode putatively GPI-modified cell wall proteins. The remaining three, RBT2, RBT4, and RBT7, encode, respectively, an apparent ferric reductase, a plant pathogenesis-related protein (PR-1), and a putative secreted RNase T2. The expression of RBT1, RBT4, RBT5, HWP1, and WAP1 was induced in wild-type cells during the switch from the yeast form to filamentous growth, indicating the importance of TUP1 in regulating this process and implicating the RBTs in hyphal-specific functions. We produced knockout strains in C. albicans for RBT1, RBT2, RBT4, RBT5, and WAP1 and detected no phenotypes on several laboratory media. However, two animal models for C. albicans infection, a rabbit cornea model and a mouse systemic infection model, revealed that rbt1Δ and rbt4Δ strains had significantly reduced virulence. TUP1 appears, therefore, to regulate many genes in C. albicans, a significant fraction of which are induced during filamentous growth, and some of which participate in pathogenesis.

scholarly journals Antimicrobial Photodynamic Inactivation Inhibits Candida albicans Virulence Factors and ReducesIn VivoPathogenicity

2012 ◽  
Vol 57 (1) ◽  
pp. 445-451 ◽  
Author(s):  
Ilka Tiemy Kato ◽  
Renato Araujo Prates ◽  
Caetano Padial Sabino ◽  
Beth Burgwyn Fuchs ◽  
George P. Tegos ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Virulence Factors ◽  
Sodium Dodecyl ◽  
Systemic Infection ◽  
Tube Formation ◽  
Photodynamic Inactivation ◽  
Content Type ◽  
Daughter Cells

ABSTRACTThe objective of this study was to evaluate whetherCandida albicansexhibits altered pathogenicity characteristics following sublethal antimicrobial photodynamic inactivation (APDI) and if such alterations are maintained in the daughter cells.C. albicanswas exposed to sublethal APDI by using methylene blue (MB) as a photosensitizer (0.05 mM) combined with a GaAlAs diode laser (λ 660 nm, 75 mW/cm2, 9 to 27 J/cm2).In vitro, we evaluated APDI effects onC. albicansgrowth, germ tube formation, sensitivity to oxidative and osmotic stress, cell wall integrity, and fluconazole susceptibility.In vivo, we evaluatedC. albicanspathogenicity with a mouse model of systemic infection. Animal survival was evaluated daily. Sublethal MB-mediated APDI reduced the growth rate and the ability ofC. albicansto form germ tubes compared to untreated cells (P< 0.05). Survival of mice systemically infected withC. albicanspretreated with APDI was significantly increased compared to mice infected with untreated yeast (P< 0.05). APDI increasedC. albicanssensitivity to sodium dodecyl sulfate, caffeine, and hydrogen peroxide. The MIC for fluconazole forC. albicanswas also reduced following sublethal MB-mediated APDI. However, none of those pathogenic parameters was altered in daughter cells ofC. albicanssubmitted to APDI. These data suggest that APDI may inhibit virulence factors and reducein vivopathogenicity ofC. albicans. The absence of alterations in daughter cells indicates that APDI effects are transitory. The MIC reduction for fluconazole following APDI suggests that this antifungal could be combined with APDI to treatC. albicansinfections.

scholarly journals Comparison between efficacy of allicin and fluconazole against Candida albicans in vitro and in a systemic candidiasis mouse model

2011 ◽  
Vol 315 (2) ◽  
pp. 87-93 ◽  
Author(s):  
Alireza Khodavandi ◽  
Fahimeh Alizadeh ◽  
Nabil S. Harmal ◽  
Shiran M. Sidik ◽  
Fauziah Othman ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Systemic Candidiasis

Pathogenicity of Candida tropicalis and Candida albicans after gastrointestinal inoculation in mice

1980 ◽  
Vol 29 (2) ◽  
pp. 808-813 ◽  
Author(s):  
J R Wingard ◽  
J D Dick ◽  
W G Merz ◽  
G R Sandford ◽  
R Saral ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Lung Tissue ◽  
Candida Tropicalis ◽  
Cytotoxic Drugs ◽  
Clinical Isolates ◽  
Yeast Cells ◽  
Gastrointestinal Mucosa ◽  
Compromised Host ◽  
Adult Mice

The ability of clinical isolates of Candida albicans and candida tropicalis to invade through normal and damaged gastrointestinal mucosa was determined. Adult mice were treated with either gentamicin or gentamicin and cytarabine. Suspensions of yeast cells (10(7)) were administered through a catheter intraesophageally. Invasion was determined by culturing liver, kidney, and lung tissue from mice sacrificed after 48 h. C. albicans and C. tropicalis were incapable of invading through normal gastrointestinal mucosa in mice treated only with gentamicin. Two isolates of C. tropicalis penetrated the damaged gastrointestinal mucosa in 69% (49 of 71) of mice treated with gentamicin and cytarabine. In contrast, three isolates of C. albicans penetrated he damaged gastrointestinal mucosa in only 23% (14 of 62) of mice. These results suggest that C. tropicalis is more capable of invading through damaged gastrointestinal mucosa than C. albicans. The observations in this mouse model parallel those seen in patients on cytotoxic drugs. Therefore, this model offers a tool for investigation of the pathogenicity of these organisms in a model analogous to the compromised host.

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