scholarly journals High-Frequency Genetic Contents Variations in Clinical Candida albicans Isolates

2011 ◽  
Vol 34 (5) ◽  
pp. 624-631 ◽  
Author(s):  
Feng Yang ◽  
Tian-Hua Yan ◽  
Elena Rustchenko ◽  
Ping-Hui Gao ◽  
Yan Wang ◽  
...  
Keyword(s):  
Candida Albicans ◽  
High Frequency

Ultrastructural Changes of Candida albicans Species Induced by the Presence of Sodium Diclofenac

2017 ◽  
Vol 68 (11) ◽  
pp. 2566-2569 ◽  
Author(s):  
Elena Rusu ◽  
Ionela Sarbu ◽  
Magdalena Mitache ◽  
Horatiu Moldovan ◽  
Carmen Ioana Biris ◽  
...  
Keyword(s):  
Candida Albicans ◽  
High Frequency ◽  
Fungal Infections ◽  
Diagnostic Methods ◽  
Ultrastructural Changes ◽  
Frequency Of Occurrence ◽  
Medical Treatments ◽  
Sodium Diclofenac ◽  
Cell Wall Disruption ◽  
Candidiasis Treatment

The high frequency of occurrence of candidiasis as well as high mortality of patients with immunosuppression cause a tendency toward better understanding of Candida albicans species virulence factors and developing sensitive and specific diagnostic methods, and appropriate strategies of candidiasis treatment. In recent decades the incidence of fungal infections has alarming increases because of advanced medical treatments. In this study was analyzed possible ultrastructural changes of the species C. albicans cells following treatment with sodium diclofenac at various concentrations. Following treatment of C. albicans cells with sodium diclofenac 1 mM and 2 mM changes in the plasmalemma can be noticed, changes in the density of cell wall, disruption and necrotic appearance of the cytoplasm.

scholarly journals ACandida albicansCRISPR system permits genetic engineering of essential genes and gene families

2015 ◽  
Vol 1 (3) ◽  
pp. e1500248 ◽  
Author(s):  
Valmik K. Vyas ◽  
M. Inmaculada Barrasa ◽  
Gerald R. Fink
Keyword(s):  
Candida Albicans ◽  
Genetic Engineering ◽  
High Frequency ◽  
Target Genes ◽  
Gene Families ◽  
Induced Mutations ◽  
Pathogenic Yeast ◽  
Crispr System ◽  
Gene Knockouts ◽  
Major Impediment

Candida albicansis a pathogenic yeast that causes mucosal and systematic infections with high mortality. The absence of facile molecular genetics has been a major impediment to analysis of pathogenesis. The lack of meiosis coupled with the absence of plasmids makes genetic engineering cumbersome, especially for essential functions and gene families. We describe aC. albicansCRISPR system that overcomes many of the obstacles to genetic engineering in this organism. The high frequency with which CRISPR-induced mutations can be directed to target genes enables easy isolation of homozygous gene knockouts, even without selection. Moreover, the system permits the creation of strains with mutations in multiple genes, gene families, and genes that encode essential functions. This CRISPR system is also effective in a fresh clinical isolate of undetermined ploidy. Our method transforms the ability to manipulate the genome ofCandidaand provides a new window into the biology of this pathogen.

scholarly journals High-frequency switching in Candida albicans.

1992 ◽  
Vol 5 (2) ◽  
pp. 183-203 ◽  
Author(s):  
D R Soll
Keyword(s):  
Candida Albicans ◽  
High Frequency ◽  
Molecular Mechanisms ◽  
Phenotypic Variability ◽  
Epigenetic Mechanism ◽  
Cell Phenotype ◽  
Wall Structures ◽  
Specific Antigens ◽  
Unique Cell ◽  
System Switching

Most strains of Candida albicans are capable of switching frequently and reversibly between a number of phenotypes distinguishable by colony morphology. A number of different switching systems have been defined according to the limited set of phenotypes in each switching repertoire, and each strain appears to possess a single system. Switching can affect many aspects of cellular physiology and morphology and appears to be a second level of phenotypic variability superimposed upon the bud-hypha transition. The most dramatic switching system so far identified is the "white-opaque transition." This system dramatizes the extraordinary effects switching can have on the budding cell phenotype, including the synthesis of opaque-specific antigens, the expression of white-specific and opaque-specific genes, and the genesis of unique cell wall structures. Switching has been demonstrated to occur at sites of infection and between episodes of recurrent vaginitis, and it may function to generate variability in commensal and infecting populations for adaptive reasons. Although the molecular mechanisms involved in the switch event are not understood, recent approaches to its elucidation are discussed and an epigenetic mechanism is proposed.

scholarly journals Development of autonomously replicating plasmids for Candida albicans.

1987 ◽  
Vol 7 (1) ◽  
pp. 209-217 ◽  
Author(s):  
M B Kurtz ◽  
M W Cortelyou ◽  
S M Miller ◽  
M Lai ◽  
D R Kirsch
Keyword(s):  
Molecular Weight ◽  
Candida Albicans ◽  
High Molecular Weight ◽  
High Frequency ◽  
Tandem Repeats ◽  
Southern Hybridization ◽  
Autonomously Replicating Sequence ◽  
Multiple Copies ◽  
Total Dna ◽  
Orthogonal Field

A pool of Candida albicans RsaI fragments cloned onto a vector containing pBR322 sequences and the Candida ADE2 gene was used to transform a Candida ade2 mutant to adenine protrophy. A potential autonomously replicating sequence (ARS) in Candida DNA was identified by two criteria: instability of the selectable marker in the absence of selection and the presence of free plasmid in total DNA preparations. Plasmids carrying the ARS transformed C. albicans at a high frequency (200 to 1,000 ADE+ transformants per microgram of DNA), and Southern hybridization analysis of these transformants indicated that multiple copies of the plasmid sequences were present and that, although they were present in high-molecular-weight molecules, these sequences had not undergone rearrangement. Orthogonal field alternation gel electrophoresis indicated that the high-molecular-weight transforming sequences were not associated with any chromosome. The simplest interpretation to account for these data is that the transforming sequences are present as oligomers consisting of head-to-tail tandem repeats. The transformed strains occasionally yield stable segregants in which the transforming sequences are integrated into the chromosome as repeats. The Candida sequence responsible for the ARS phenotype was limited to a single 0.35-kilobase RsaI fragment which is present in one copy per haploid genome.

scholarly journals In Candida albicans, White-Opaque Switchers Are Homozygous for Mating Type

Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 737-745 ◽  
Author(s):  
Shawn R Lockhart ◽  
Claude Pujol ◽  
Karla J Daniels ◽  
Matthew G Miller ◽  
Alexander D Johnson ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mating Type ◽  
High Frequency ◽  
Fungal Pathogen ◽  
Clinical Isolates ◽  
Very High Frequency ◽  
Type Locus ◽  
Mating Type Locus ◽  
The Relationship ◽  
Very High

Abstract The relationship between the configuration of the mating type locus (MTL) and white-opaque switching in Candida albicans has been examined. Seven genetically unrelated clinical isolates selected for their capacity to undergo the white-opaque transition all proved to be homozygous at the MTL locus, either MTLa or MTLα. In an analysis of the allelism of 220 clinical isolates representing the five major clades of C. albicans, 3.2% were homozygous and 96.8% were heterozygous at the MTL locus. Of the seven identified MTL homozygotes, five underwent the white-opaque transition. Of 20 randomly selected MTL heterozygotes, 18 did not undergo the white-opaque transition. The two that did were found to become MTL homozygous at very high frequency before undergoing white-opaque switching. Our results demonstrate that only MTL homozygotes undergo the white-opaque transition, that MTL heterozygotes that become homozygous at high frequency exist, and that the generation of MTL homozygotes and the white-opaque transition occur in isolates in different genetic clades of C. albicans. Our results demonstrate that mating-competent strains of C. albicans exist naturally in patient populations and suggest that mating may play a role in the genesis of diversity in this pernicious fungal pathogen.

scholarly journals The Histone Deacetylase Genes HDA1 andRPD3 Play Distinct Roles in Regulation of High-Frequency Phenotypic Switching in Candida albicans

2001 ◽  
Vol 183 (15) ◽  
pp. 4614-4625 ◽  
Author(s):  
T. Srikantha ◽  
L. Tsai ◽  
K. Daniels ◽  
A. J. S. Klar ◽  
D. R. Soll
Keyword(s):  
Candida Albicans ◽  
Histone Deacetylase ◽  
High Frequency ◽  
Protein Gene ◽  
Phenotypic Switching ◽  
Specific Gene ◽  
Slight Reduction ◽  
Specific Expression ◽  
White Phase ◽  
High Level

ABSTRACT Five histone deacetylase genes (HDA1, RPD3, HOS1, HOS2, and HOS3) have been cloned fromCandida albicans and characterized. Sequence analysis and comparison with 17 additional deacetylases resulted in a phylogenetic tree composed of three major groups. Transcription of the deacetylases HDA1 and RPD3 is down-regulated in the opaque phase of the white-opaque transition in strain WO-1. HOS3 is selectively transcribed as a 2.5-kb transcript in the white phase and as a less-abundant 2.3-kb transcript in the opaque phase. HDA1 andRPD3 were independently deleted in strain WO-1, and both switching between the white and opaque phases and the downstream regulation of phase-specific genes were analyzed. Deletion ofHDA1 resulted in an increase in the frequency of switching from the white phase to the opaque phase, but had no effect on the frequency of switching from the opaque phase to the white phase. Deletion of RPD3 resulted in an increase in the frequency of switching in both directions. Deletion ofHDA1 resulted in reduced white-phase-specific expression of the EFG1 3.2-kb transcript, but had no significant effect on white-phase-specific expression of WH11 or opaque-phase-specific expression of OP4, SAP1, andSAP3. Deletion of RPD3 resulted in reduced opaque-phase-specific expression of OP4, SAP1, and SAP3 and a slight reduction of white-phase-specific expression of WH11 and 3.2-kbEFG1. Deletion of neither HDA1 norRPD3 affected the high level of white-phase expression and the low level of opaque-phase expression of the MADS box protein gene MCM1, which has been implicated in the regulation of opaque-phase-specific gene expression. In addition, there was no effect on the phase-regulated levels of expression of the other deacetylase genes. These results demonstrate that the two deacetylase genes HDA1 and RPD3 play distinct roles in the suppression of switching, that the two play distinct and selective roles in the regulation of phase-specific genes, and that the deacetylases are in turn regulated by switching.

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