sodium-dodecyl-sulfate and Candidiasis

Calcium-permeable transient receptor potential (TRP) channels exist in eukaryotic cells from yeasts to animals and plants. and they act as sensors for various stresses. Arabidopsis thaliana calcium permeable stress-gated cation channel 1 (AtCSC1) was the first plant calcium-permeable TRP to be described and can be activated by hyperosmotic shock. Candida albicans CaPHM7 is one of the sequence homologs of AtCSC1, but its function remains unknown.. We show here that CaPhm7 is localized to the plasma membrane in both the yeast and hyphal cells of C. albicans. C. albicans cells lacking CaPHM7 are sensitive to SDS and ketoconazole but tolerant to rapamycin and zinc. In addition, deletion of CaPHM7 leads to a filamentation defect, reduced colony growth and attenuated virulence in the mouse model of systemic infection.. CaPhm7 is involved in the regulation of ion homeostasis, drug tolerance, filamentation and virulence in this important human fungal pathogen. CaPhm7 could be a potential target of antifungal drugs.

Topics: Animals; Candida albicans; Candidiasis; Disease Models, Animal; Drug Resistance, Fungal; Fungal Proteins; Homeostasis; Hyphae; Ketoconazole; Mice; Sirolimus; Sodium Dodecyl Sulfate; Transient Receptor Potential Channels; Virulence; Zinc

Methylene Blue (MB) has been widely used in antimicrobial Photodynamic Therapy (aPDT), however, the mechanisms of action (Type I or Type II) are defined by its state of aggregation. In this sense, the identification of the relationships between aggregation, the mechanisms of action and the effectiveness against microorganisms, as well as the establishment of the means and the formulations that may favor the most effective mechanisms, are essential. Thus, the objective of this study was to assess the in vitro aPDT efficacies against Candida albicans, by using MB in vehicles which may influence the aggregation and present an oral formulation (OF) containing MB, to be used in clinical aPDT procedures. The efficacy of MB at 20 mg L-1 was tested in a range of vehicles (water, physiological solution - NaCl 0.9%, phosphate saline buffer - PBS, sodium dodecyl sulfate 0.25% - SDS and urea 1 mol L-1) in a C. albicans planktonic culture, when using 4.68 J cm-2 of 640 ± 12 nm LED for the irradiations, as well as 5 minutes of pre-irradiation time, together with measuring the UFC mL-1. Based upon these analyses, an OF containing MB in the most effective vehicle was tested in the biofilms, as a proposal for clinical applications. When comparing some of the vehicles, sodium dodecyl sulfate was the only one that enhanced an MB aPDT efficacy in a planktonic C. albicans culture. This OF was tested in the biofilms and 50 mg L-1 MB was necessary, in order to achieve some reduction in the cell viabilities after the various treatments. The light dosimetries still need further adaptations, in order for this formulation to be used in clinical applications. The present research has indicated that the development of this formulation for the control of MB aggregations may result in more effective clinical protocols.

Topics: Antifungal Agents; Biofilms; Candida albicans; Candidiasis; Dimerization; Humans; Methylene Blue; Pharmaceutical Vehicles; Photochemotherapy; Photosensitizing Agents; Sodium Dodecyl Sulfate

Candida albicans is a common opportunistic pathogen that causes a wide variety of diseases in a human immunocompromised host leading to death. In a pathogen, cell wall proteins are important for stability as well as for acting as antigenic determinants and virulence factors. Pir32 is a cell wall protein and member of the Pir protein family previously shown to be upregulated in response to macrophage contact and whose other member, Pir1, was found to be necessary for cell wall rigidity. The purpose of this study is to characterize Pir32 by generating a homozygous null strain and comparing the phenotype of the null with that of the wild-type parental strain as far as filamentation, virulence in a mouse model of disseminated candidiasis, resistance to oxidative stress and cell wall disrupting agents, in addition to adhesion, biofilm capacities, and cell wall chitin content. Our mutant was shown to be hyperfilamentous, resistant to sodium dodecyl sulfate, hydrogen peroxide, sodium chloride, and more virulent in a mouse model when compared to the wild type. These results were unexpected, considering that most cell wall mutations weaken the wall and render it more susceptible to external stress factors and suggests the possibility of a cell surface compensatory mechanism. As such, we measured cell wall chitin deposition and found a twofold increase in the mutant, possibly explaining the above-observed phenotypes.

Topics: Animals; Candida albicans; Candidiasis; Cell Wall; Chitin; Disease Models, Animal; Fungal Proteins; Gene Deletion; Hydrogen Peroxide; Mice; Mice, Inbred BALB C; Microbial Viability; Microscopy; Osmotic Pressure; Oxidative Stress; Sodium Chloride; Sodium Dodecyl Sulfate; Stress, Physiological; Virulence

The protein phosphatase calcineurin is a key mediator of virulence and antifungal susceptibility of multiple fungal pathogens including Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, and has clinical potential as a therapeutic target to increase the efficacy of the current antifungal armamentarium. Despite the importance of this signaling pathway, few components of the calcineurin-signaling pathway are known in C. albicans. Here we identified and analyzed additional components of the C. albicans calcineurin cascade, including the RCN1 (regulator of calcineurin1), MID1, and CCH1 genes, which mediate calcineurin functions in other species. When heterologously expressed in Saccharomyces cerevisiae, C. albicans Rcn1 inhibited calcineurin function. Although rcn1/rcn1, mid1/mid1, and cch1/cch1 mutant strains share some phenotypes with calcineurin mutants, they do not completely recapitulate the phenotypes of a calcineurin mutant strain. These studies extend our understanding of the C. albicans calcineurin signaling cascade and its host-niche specific role in virulence.

Topics: Amino Acid Sequence; Animals; Antifungal Agents; Calcineurin; Candida albicans; Candidiasis; Fluconazole; Fungal Proteins; Gene Expression Regulation, Fungal; Genetic Complementation Test; Lithium Chloride; Mice; Mice, Inbred ICR; Molecular Sequence Data; Mutation; Saccharomyces cerevisiae; Sequence Homology, Amino Acid; Signal Transduction; Sodium Dodecyl Sulfate; Virulence

In this study, we measured time-kills and post-antifungal effects (PAFEs) for micafungin against Candida albicans (n=4), Candida glabrata (n=3), Candida parapsilosis (n=3) and Candida krusei (n=2) isolates and further characterised the PAFEs. Minimum inhibitory concentrations (MICs) were 0.5-1.0 mg/L against C. parapsilosis and 0.008-0.125 mg/L against the other species. Micafungin caused kills >1 log at 1 x MIC, 4 x MIC (range 1.19-3.10 log) and 16 x MIC (2.27-3.68 log), achieving fungicidal levels (> or = 3 log) against nine isolates. One-hour drug exposure during PAFE experiments resulted in kills of 0.73-2.88 log and 1.72-3.55 log at 4 x and 16 x MIC, respectively, achieving fungicidal levels against five isolates. Isolates of each species collected 8 h after a 1-h exposure to micafungin (4 x and 16 x MIC) were hypersusceptible to sodium dodecyl sulphate (SDS) and Calcofluor White. Cells tested during the PAFE period demonstrated cell wall disturbances as evident on electron micrographs as well as significant reductions in adherence to epithelial cells. Phagocytosis by J774 macrophages was significantly enhanced for three PAFE isolates tested. Micafungin is fungicidal and exerts PAFEs that kill diverse Candida spp., disturb cell walls of viable organisms, reduce adherence and enhance susceptibility to phagocytosis.

Topics: Animals; Antifungal Agents; Benzenesulfonates; Candida; Candidiasis; Cell Adhesion; Cell Line; Cell Wall; Cells, Cultured; Echinocandins; Epithelial Cells; Humans; Lipopeptides; Macrophages; Micafungin; Mice; Microbial Sensitivity Tests; Microbial Viability; Microscopy, Electron, Transmission; Phagocytosis; Sodium Dodecyl Sulfate; Time Factors

The target of rapamycin complex 1 (TORC1) is the central controller of growth in eukaryotic cells. As one of the downstream targets of TORC1, the protein kinase ScSch9p plays multiple roles in stress resistance, longevity and nutrient sensing in Saccharomyces cerevisiae. In this study, we demonstrate that Candida albicans cells with CaSCH9 deleted have reduced cell sizes and show a delayed log-phase growth. In addition, deletion of CaSCH9 renders C. albicans cells sensitive to rapamycin, caffeine and sodium dodecyl sulfate. Similar to ScSCH9, deletion of CaSCH9 also causes C. albicans cells to become sensitive to cations, but does not lead to a defect in the utilization of galactose. Furthermore, deletion of CaSCH9 affects the filamentation of C. albicans cells and attenuates the virulence in a mouse mode of systemic candidiasis. Therefore, CaSch9p is an important regulator for the cell growth, filamentation and virulence of this human fungal pathogen.

Topics: Animals; Antifungal Agents; Caffeine; Candida albicans; Candidiasis; Fungal Proteins; Galactose; Gene Deletion; Male; Mice; Mice, Inbred BALB C; Protein Kinases; Sirolimus; Sodium Dodecyl Sulfate; Survival Analysis; Virulence; Virulence Factors

Catalase-deficient strains of the human pathogenic yeast Candida albicans were constructed using the URA-blaster method. The disruptant was viable and grew normally in an ordinary culture condition, but became extremely sensitive to treatment with hydrogen peroxide. No catalase activity was observed in a catalase (CCT)-gene-disrupted strain, 1F5-4-1, suggesting that there were no other catalase or catalase-like enzymes in this yeast. The disruptant was shown to be sensitive to higher temperature and to low concentrations of SDS, NP-40, or Triton X-100. After a wild-type CCT gene was reintroduced into the disruptant, catalase activity was restored and the strain became moderately sensitive to treatment with hydrogen peroxide. However, neither the temperature sensitivity nor the susceptibility to SDS observed in the disruptant was restored in the CCT-reintroduced strain. A model infection experiment using wild-type and dCCT strains showed that the disruptants disappeared more rapidly than the wild-type strain in mouse liver, lung, and spleen. These results suggest that the catalase plays a significant role in survival in the host immune system and thus leads this organism to establish infection in the host.

Topics: Animals; Candida albicans; Candidiasis; Catalase; Cyclophosphamide; Detergents; Fungal Proteins; Gene Targeting; Genetic Complementation Test; Hot Temperature; Hydrogen Peroxide; Liver; Lung; Mice; Molecular Sequence Data; Octoxynol; Phenotype; Polyethylene Glycols; Reactive Oxygen Species; Recombinant Fusion Proteins; Sodium Dodecyl Sulfate; Spheroplasts; Spleen; Transformation, Genetic

Six of 11 human immunodeficiency virus (HIV)-infected patients with chronic diarrhea, shedding only Candida spp. in their stools, elicited a Candida-specific secretory immunoglobulin A response. Similar responses were identified in only 1 of 10 HIV-positive patients with chronic diarrhea but without Candida spp. and in none of 10 HIV-negative subjects without diarrhea. Candida spp. may play a role in the etiology of chronic diarrhea associated with HIV infection.

Topics: AIDS-Related Opportunistic Infections; Antigens, Fungal; Blotting, Western; Candidiasis; Chronic Disease; Diarrhea; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Feces; HIV Infections; Humans; Immunoglobulin A, Secretory; Intestinal Mucosa; Sodium Dodecyl Sulfate