Approaches to the mechanism of dimorphic manifestation using several morphological mutant strains of Candida albicans.

1989 ◽  
Vol 30 (2) ◽  
pp. 112-129
Author(s):  
Tamio Hiratani ◽  
Yukiyo Asagi ◽  
Junko Nagata ◽  
Hideaki Usuda ◽  
Hideyo Yamaguchi
Keyword(s):  
Candida Albicans ◽  
Morphological Mutant ◽  
Mutant Strains

Lethality of Candida strains as influenced by the host

1975 ◽  
Vol 21 (5) ◽  
pp. 648-654 ◽  
Author(s):  
Cora G. Saltarelli ◽  
Kathi Ann Gentile ◽  
Susan C. Mancuso
Keyword(s):  
Candida Albicans ◽  
Statistical Analysis ◽  
Comparative Study ◽  
Proteolytic Activity ◽  
Germ Tube ◽  
Culture Media ◽  
Tube Formation ◽  
Nutritional Requirements ◽  
Morphological Mutant ◽  
Mutant Strains

A comparative study of the pathogenicity of Candida albicans morphological mutant strains was made to relate chlamydospore production, germ tube formation, and proteolytic activity to candidiasis in mice. It was observed that the mycelium strains were more lethal than the yeast-like strains and that neither chlamydospore production, germ tube formation, nor nutritional requirements was related to pathogenicity in mice. Statistical analysis indicated that the culture media of the organisms and the strain and sex of the mice into which the cells were injected were important factors in the development of pathogenicity.

Antifungal Activity Directed Toward the Cell Wall by 2-Cyclohexylidenhydrazo- 4-Phenyl-Thiazole Against Candida albicans

2019 ◽  
Vol 19 (4) ◽  
pp. 428-438 ◽  
Author(s):  
Nívea P. de Sá ◽  
Ana P. Pôssa ◽  
Pilar Perez ◽  
Jaqueline M.S. Ferreira ◽  
Nayara C. Fonseca ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Mammalian Cells ◽  
C Elegans ◽  
Buccal Epithelial Cells ◽  
Mutant Strains ◽  
Low Toxicity ◽  
High Concentrations ◽  
Mic Value

<p>Background: The increasing incidence of invasive forms of candidiasis and resistance to antifungal therapy leads us to seek new and more effective antifungal compounds. </P><P> Objective: To investigate the antifungal activity and toxicity as well as to evaluate the potential targets of 2- cyclohexylidenhydrazo-4-phenyl-thiazole (CPT) in Candida albicans. </P><P> Methods: The antifungal activity of CPT against the survival of C. albicans was investigated in Caenorhabditis elegans. Additionally, we determined the effect of CPT on the inhibition of C. albicans adhesion capacity to buccal epithelial cells (BECs), the toxicity of CPT in mammalian cells, and the potential targets of CPT in C. albicans. </P><P> Results: CPT exhibited a minimum inhibitory concentration (MIC) value of 0.4-1.9 µg/mL. Furthermore, CPT at high concentrations (>60 x MIC) showed no or low toxicity in HepG2 cells and <1% haemolysis in human erythrocytes. In addition, CPT decreased the adhesion capacity of yeasts to the BECs and prolonged the survival of C. elegans infected with C. albicans. Analysis of CPT-treated cells showed that their cell wall was thinner than that of untreated cells, especially the glucan layer. We found that there was a significantly lower quantity of 1,3-β-D-glucan present in CPT-treated cells than that in untreated cells. Assays performed on several mutant strains showed that the MIC value of CPT was high for its antifungal activity on yeasts with defective 1,3-β-glucan synthase. </P><P> Conclusion: In conclusion, CPT appears to target the cell wall of C. albicans, exhibits low toxicity in mammalian cells, and prolongs the survival of C. elegans infected with C. albicans.</p>

scholarly journals Characterization of mutant strains of Candida albicans deficient in expression of a surface determinant.

1993 ◽  
Vol 61 (8) ◽  
pp. 3449-3458 ◽  
Author(s):  
W L Chaffin ◽  
B Collins ◽  
J N Marx ◽  
G T Cole ◽  
K J Morrow
Keyword(s):  
Candida Albicans ◽  
Mutant Strains

scholarly journals Limited Role of Secreted Aspartyl Proteinases Sap1 to Sap6 in Candida albicans Virulence and Host Immune Response in Murine Hematogenously Disseminated Candidiasis

2010 ◽  
Vol 78 (11) ◽  
pp. 4839-4849 ◽  
Author(s):  
Alexandra Correia ◽  
Ulrich Lermann ◽  
Luzia Teixeira ◽  
Filipe Cerca ◽  
Sofia Botelho ◽  
...  
Keyword(s):  
Immune Response ◽  
Candida Albicans ◽  
Significant Role ◽  
Murine Model ◽  
Null Mutant ◽  
Wild Type ◽  
Survival Times ◽  
Disseminated Candidiasis ◽  
Mutant Strains ◽  
Aspartyl Proteinases

ABSTRACTCandida albicanssecreted aspartyl proteinases (Saps) are considered virulence-associated factors. Several members of the Sap family were claimed to play a significant role in the progression of candidiasis established by the hematogenous route. This assumption was based on the observed attenuated virulence ofsap-null mutant strains. However, the exclusive contribution ofSAPgenes to their attenuated phenotype was not unequivocally confirmed, as the Ura status of these mutant strains could also have contributed to the attenuation. In this study, we have reassessed the importance ofSAP1toSAP6in a murine model of hematogenously disseminated candidiasis usingsap-null mutant strains not affected in theirURA3gene expression and compared their virulence phenotypes with those of Ura-blastersapmutants. The median survival time of BALB/c mice intravenously infected with a mutant strain lackingSAP1toSAP3was equivalent to that of mice infected with wild-type strain SC5314, while those infected with mutant strains lackingSAP5showed slightly extended survival times. Nevertheless, no differences could be observed between the wild type and a Δsap456mutant in their abilities to invade mouse kidneys. Likewise, a deficiency inSAP4toSAP6had no noticeable impact on the immune response elicited in the spleens and kidneys ofC. albicans-infected mice. These results contrast with the behavior of equivalent Ura-blaster mutants, which presented a significant reduction in virulence. Our results suggest that Sap1 to Sap6 do not play a significant role inC. albicansvirulence in a murine model of hematogenously disseminated candidiasis and that, in this model, Sap1 to Sap3 are not necessary for successfulC. albicansinfection.

Mutant alleles of the essential 14-3-3 gene in Candida albicans distinguish between growth and filamentation

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1911-1924 ◽  
Author(s):  
Glen E. Palmer ◽  
Kevin J. Johnson ◽  
Sumana Ghosh ◽  
Joy Sturtevant
Keyword(s):  
Candida Albicans ◽  
Random Mutagenesis ◽  
Optimal Growth ◽  
Temperature Sensitive ◽  
Nucleotide Substitutions ◽  
Nutrient Sources ◽  
Cellular Processes ◽  
Mutant Strains ◽  
Opportunistic Fungal Pathogen ◽  
The Individual

The opportunistic fungal pathogen Candida albicans has the ability to exploit diverse host environments and can either reside commensally or cause disease. In order to adapt to its new environment it must respond to new physical conditions, nutrient sources, and the host immune response. This requires the co-regulation of multiple signalling networks. The 14-3-3 family of proteins is highly conserved in all eukaryotic species. These proteins regulate signalling pathways involved in cell survival, the cell cycle, and differentiation, and effect their functions via interactions with phosphorylated serines/threonines. In C. albicans there is only one 14-3-3 protein, Bmh1p, and it is required for vegetative growth and optimal filamentation. In order to dissect separate functions of Bmh1p in C. albicans, site-directed nucleotide substitutions were made in the C. albicans BMH1 gene based on studies in other species. Putative temperature-sensitive, ligand-binding and dimerization mutants were constructed. In addition two mutant strains identified through random mutagenesis were analysed. All five mutant strains demonstrated varying defects in growth and filamentation. This paper begins to segregate functions of Bmh1p that are required for optimal growth and the different filamentation pathways. These mutant strains will allow the identification of 14-3-3 target interactions and correlate the individual functions of Bmh1p to cellular processes involved in pathogenesis.

ALS3 and ALS8 represent a single locus that encodes a Candida albicans adhesin; functional comparisons between Als3p and Als1p

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2415-2428 ◽  
Author(s):  
Xiaomin Zhao ◽  
Soon-Hwan Oh ◽  
Georgina Cheng ◽  
Clayton B. Green ◽  
Jennifer A. Nuessen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Fluorescent Protein ◽  
Mutational Analysis ◽  
Oral Candidiasis ◽  
Tube Formation ◽  
Single Locus ◽  
Wild Type ◽  
Mutant Strains ◽  
Encoded Proteins

The ALS (agglutinin-like sequence) gene family of Candida albicans encodes eight cell-surface glycoproteins, some of which are involved in adherence to host surfaces. A mutational analysis of each ALS gene is currently being performed to deduce the functions of the encoded proteins and to better understand the role of these proteins in C. albicans biology and pathogenesis. This paper describes construction of an als3/als3 mutant and comparison of its phenotype to an als1/als1 strain. Efforts to disrupt ALS3 indicated that the gene could be deleted in two transformation steps, suggesting that the gene is encoded by a single locus and that the ALS3-like locus, ALS8, does not exist. Strains lacking ALS3 or ALS1 did not exhibit a defect in germ tube formation when grown in RPMI 1640 medium, but the als1/als1 mutant formed significantly fewer germ tubes in Lee medium. Analysis of ALS3 and ALS1 promoter activity using green fluorescent protein (GFP) reporter strains and flow cytometry showed that when cells are placed into medium that promotes germ tube formation, ALS1 is transcribed prior to ALS3. Comparison of the mutant strains in adhesion assays showed that the als3/als3 strain was defective in adhesion to both human umbilical vein endothelial cells (HUVEC) and buccal epithelial cells (BEC), but not to fibronectin-coated plastic plates. In contrast, the als1/als1 strain showed decreased adherence to HUVEC, but adherence to BEC and fibronectin were the same as wild-type controls. Inoculation of the buccal reconstituted human epithelium (RHE) model of oral candidiasis with the mutant strains showed nearly a total lack of adhesion and epithelial destruction by the als3/als3 mutant while the als1/als1 strain showed only a slightly reduced degree of epithelial destruction compared to the wild-type control. Adhesion data presented here suggest that, in the assays performed, loss of Als3p affects C. albicans adhesion more than loss of Als1p. Collectively, these results demonstrate functional similarities and differences between Als1p and Als3p, and suggest the potential for more complex interrelationships between the ALS genes and their encoded proteins.

scholarly journals Deletion of the Dynein Heavy-Chain Gene DYN1 Leads to Aberrant Nuclear Positioning and Defective Hyphal Development in Candida albicans

2004 ◽  
Vol 3 (6) ◽  
pp. 1574-1588 ◽  
Author(s):  
R. Martin ◽  
A. Walther ◽  
J. Wendland
Keyword(s):  
Candida Albicans ◽  
Heavy Chain ◽  
Time Lapse ◽  
Yeast Cells ◽  
Chain Gene ◽  
Wild Type ◽  
Heavy Chain Gene ◽  
Mutant Strains ◽  
Mutant Phenotypes

ABSTRACT Cytoplasmic dynein is a microtubule-associated minus-end-directed motor protein. CaDYN1 encodes the single dynein heavy-chain gene of Candida albicans. The open reading frames of both alleles of CaDYN1 were completely deleted via a PCR-based approach. Cadyn1 mutants are viable but grow more slowly than the wild type. In vivo time-lapse microscopy was used to compare growth of wild-type (SC5314) and dyn1 mutant strains during yeast growth and after hyphal induction. During yeast-like growth, Cadyn1 strains formed chains of cells. Chromosomal TUB1-GFP and HHF1-GFP alleles were used both in wild-type and mutant strains to monitor the orientation of mitotic spindles and nuclear positioning in C. albicans. In vivo fluorescence time-lapse analyses with HHF1-GFP over several generations indicated defects in dyn1 cells in the realignment of spindles with the mother-daughter axis of yeast cells compared to that of the wild type. Mitosis in the dyn1 mutant, in contrast to that of wild-type yeast cells, was very frequently completed in the mother cells. Nevertheless, daughter nuclei were faithfully transported into the daughter cells, resulting in only a small number of multinucleate cells. Cadyn1 mutant strains responded to hypha-inducing media containing l-proline or serum with initial germ tube formation. Elongation of the hyphal tubes eventually came to a halt, and these tubes showed a defect in the tipward localization of nuclei. Using a heterozygous DYN1/dyn1 strain in which the remaining copy was controlled by the regulatable MAL2 promoter, we could switch between wild-type and mutant phenotypes depending on the carbon source, indicating that the observed mutant phenotypes were solely due to deletion of DYN1.

scholarly journals Ergosterol Biosynthesis Inhibitors Become Fungicidal when Combined with Calcineurin Inhibitors against Candida albicans, Candida glabrata, and Candida krusei

2003 ◽  
Vol 47 (3) ◽  
pp. 956-964 ◽  
Author(s):  
Chiatogu Onyewu ◽  
Jill R. Blankenship ◽  
Maurizio Del Poeta ◽  
Joseph Heitman
Keyword(s):  
Candida Albicans ◽  
Antifungal Agents ◽  
Calcineurin Inhibitors ◽  
Therapeutic Window ◽  
Ergosterol Biosynthesis ◽  
Drug Synergism ◽  
Wild Type ◽  
Ergosterol Biosynthesis Inhibitors ◽  
Biosynthesis Inhibitors ◽  
Mutant Strains

ABSTRACT Azoles target the ergosterol biosynthetic enzyme lanosterol 14α-demethylase and are a widely applied class of antifungal agents because of their broad therapeutic window, wide spectrum of activity, and low toxicity. Unfortunately, azoles are generally fungistatic and resistance to fluconazole is emerging in several fungal pathogens. We recently established that the protein phosphatase calcineurin allows survival of Candida albicans during the membrane stress exerted by azoles. The calcineurin inhibitors cyclosporine A (CsA) and tacrolimus (FK506) are dramatically synergistic with azoles, resulting in potent fungicidal activity, and mutant strains lacking calcineurin are markedly hypersensitive to azoles. Here we establish that drugs targeting other enzymes in the ergosterol biosynthetic pathway (terbinafine and fenpropimorph) also exhibit dramatic synergistic antifungal activity against wild-type C. albicans when used in conjunction with CsA and FK506. Similarly, C. albicans mutant strains lacking calcineurin B are markedly hypersensitive to terbinafine and fenpropimorph. The FK506 binding protein FKBP12 is required for FK506 synergism with ergosterol biosynthesis inhibitors, and a calcineurin mutation that confers FK506 resistance abolishes drug synergism. Additionally, we provide evidence of drug synergy between the nonimmunosuppressive FK506 analog L-685,818 and fenpropimorph or terbinafine against wild-type C. albicans. These drug combinations also exert synergistic effects against two other Candida species, C. glabrata and C. krusei, which are known for intrinsic or rapidly acquired resistance to azoles. These studies demonstrate that the activity of non-azole antifungal agents that target ergosterol biosynthesis can be enhanced by inhibition of the calcineurin signaling pathway, extending their spectrum of action and providing an alternative approach by which to overcome antifungal drug resistance.

scholarly journals Farnesol Anti-biofilm Activity against Candida albicans Reference and Mutant Strains

2018 ◽  
Vol 22 (6) ◽  
pp. 1-7
Author(s):  
Adriana Carreiro ◽  
Sarah Guedes ◽  
Beatriz Panariello ◽  
Paula Silveira ◽  
Malvin Janal ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mutant Strains

scholarly journals Ectopic Expression of URA3 Can Influence the Virulence Phenotypes and Proteome of Candida albicans but Can Be Overcome by Targeted Reintegration of URA3 at the RPS10 Locus

2004 ◽  
Vol 3 (4) ◽  
pp. 900-909 ◽  
Author(s):  
Alexandra Brand ◽  
Donna M. MacCallum ◽  
Alistair J. P. Brown ◽  
Neil A. R. Gow ◽  
Frank C. Odds
Keyword(s):  
Candida Albicans ◽  
Specific Activity ◽  
Gene Knockout ◽  
Ectopic Expression ◽  
Single Copy ◽  
Phenotypic Changes ◽  
Protein Levels ◽  
Mutant Strains ◽  
Monophosphate Decarboxylase ◽  
Strain Sc5314

ABSTRACT Uridine auxotrophy, based on disruption of both URA3 alleles in diploid Candida albicans strain SC5314, has been widely used to select gene deletion mutants created in this fungus by “Ura-blasting” and PCR-mediated disruption. We compared wild-type URA3 expression with levels in mutant strains where URA3 was positioned either within deleted genes or at the highly expressed RPS10 locus. URA3 expression levels differed significantly and correlated with the specific activity of Ura3p, orotidine 5′-monophosphate decarboxylase. Reduced URA3 expression following integration at the GCN4 locus was associated with an attenuation of virulence. Furthermore, a comparison of the SC5314 (URA3) and CAI-4 (ura3) proteomes revealed that inactivation of URA3 caused significant changes in the levels of 14 other proteins. The protein levels of all except one were partially or fully restored by the reintegration of a single copy of URA3 at the RPS10 locus. Transcript levels of genes expressed ectopically at this locus in reconstituted heterozygous mutants also matched the levels found when the genes were expressed at their native loci. Therefore, phenotypic changes in C. albicans can be associated with the selectable marker rather than the target gene. Reintegration of URA3 at an appropriate expression locus such as RPS10 can offset most problems related to the phenotypic changes associated with gene knockout methodologies.

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