scholarly journals Genomic evidence for a hybrid origin of the yeast opportunistic pathogen Candida albicans

2019 ◽  
Author(s):  
Verónica Mixão ◽  
Toni Gabaldón
Keyword(s):  
Candida Albicans ◽  
Opportunistic Pathogen ◽  
Sexual Cycle ◽  
Hybrid Origin ◽  
Species Boundaries ◽  
Compelling Evidence ◽  
Parasexual Cycle ◽  
Evolution Of Virulence ◽  
Vertical Evolution ◽  
Current Species

AbstractOpportunistic yeast pathogens are of increasing medical concern. Candida albicans, the species with the highest incidence, is a natural commensal of humans that can adopt a pathogenic behaviour. This species is highly heterozygous, is an obligate diploid, and cannot undergo meiosis, adopting instead a parasexual cycle. The origin of these traits is unknown and we hypothesize they could result from ancestral hybridization. We tested this idea by analyzing available genomes of C. albicans isolates and comparing them to those of hybrid and non-hybrid strains of other Candida species. Our results show compelling evidence that C. albicans is an evolved hybrid, with levels and patterns of ancestral heterozygosity that cannot be fully explained under the paradigm of vertical evolution. Although the level of inferred divergence between the putative parental lineages (2.8%) is not clearly beyond current species boundaries in Saccharomycotina, we show here that all analyzed C. albicans strains derive from a single hybrid ancestor, which diverged by extensive loss of heterozygosis. This finding has important implications for our understanding of C. albicans evolution, including the loss of the sexual cycle, the origin of the association with humans, and the evolution of virulence traits.

scholarly journals Oral Administration of Lactobacillus helveticus LA401 and Lactobacillus gasseri LA806 Combination Attenuates Oesophageal and Gastrointestinal Candidiasis and Consequent Gut Inflammation in Mice

2021 ◽  
Vol 7 (1) ◽  
pp. 57
Author(s):  
Hélène Authier ◽  
Marie Salon ◽  
Mouna Rahabi ◽  
Bénédicte Bertrand ◽  
Claude Blondeau ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Oral Administration ◽  
Mannose Receptor ◽  
Opportunistic Pathogen ◽  
Protective Role ◽  
Lactobacillus Helveticus ◽  
Lectin Receptors ◽  
Lactobacillus Gasseri ◽  
Inflammatory Status ◽  
Gastrointestinal Candidiasis

Candida albicans is an opportunistic pathogen that causes mucosal gastrointestinal (GI) candidiasis tightly associated with gut inflammatory status. The emergence of drug resistance, the side effects of currently available antifungals and the high frequency of recurrent candidiasis indicate that new and improved therapeutics are needed. Probiotics have been suggested as a useful alternative for the management of candidiasis. We demonstrated that oral administration of Lactobacillus gasseri LA806 alone or combined with Lactobacillus helveticus LA401 in Candida albicans-infected mice decrease the Candida colonization of the oesophageal and GI tract, highlighting a protective role for these strains in C. albicans colonization. Interestingly, the probiotic combination significantly modulates the composition of gut microbiota towards a protective profile and consequently dampens inflammatory and oxidative status in the colon. Moreover, we showed that L. helveticus LA401 and/or L. gasseri LA806 orient macrophages towards a fungicidal phenotype characterized by a C-type lectin receptors signature composed of Dectin-1 and Mannose receptor. Our findings suggest that the use of the LA401 and LA806 combination might be a promising strategy to manage GI candidiasis and the inflammation it causes by inducing the intrinsic antifungal activities of macrophages. Thus, the probiotic combination is a good candidate for managing GI candidiasis by inducing fungicidal functions in macrophages while preserving the GI integrity by modulating the microbiota and inflammation.

scholarly journals Parasexuality and Ploidy Change in Candida tropicalis

2013 ◽  
Vol 12 (12) ◽  
pp. 1629-1640 ◽  
Author(s):  
Riyad N. H. Seervai ◽  
Stephen K. Jones ◽  
Matthew P. Hirakawa ◽  
Allison M. Porman ◽  
Richard J. Bennett
Keyword(s):  
Sexual Reproduction ◽  
Candida Tropicalis ◽  
Culture Conditions ◽  
Sexual Cycle ◽  
Chromosome Loss ◽  
Parasexual Cycle ◽  
Content Type ◽  
Ploidy Changes ◽  
Diploid Cells

ABSTRACTCandidaspecies exhibit a variety of ploidy states and modes of sexual reproduction. Most species possess the requisite genes for sexual reproduction, recombination, and meiosis, yet only a few have been reported to undergo a complete sexual cycle including mating and sporulation.Candida albicans, the most studiedCandidaspecies and a prevalent human fungal pathogen, completes its sexual cycle via a parasexual process of concerted chromosome loss rather than a conventional meiosis. In this study, we examine ploidy changes inCandida tropicalis, a closely related species toC. albicansthat was recently revealed to undergo sexual mating.C. tropicalisdiploid cells mate to form tetraploid cells, and we show that these can be induced to undergo chromosome loss to regenerate diploid forms by growth on sorbose medium. The diploid products are themselves mating competent, thereby establishing a parasexual cycle in this species for the first time. Extended incubation (>120 generations) ofC. tropicalistetraploid cells under rich culture conditions also resulted in instability of the tetraploid form and a gradual reduction in ploidy back to the diploid state. The fitness levels ofC. tropicalisdiploid and tetraploid cells were compared, and diploid cells exhibited increased fitness relative to tetraploid cellsin vitro, despite diploid and tetraploid cells having similar doubling times. Collectively, these experiments demonstrate distinct pathways by which a parasexual cycle can occur inC. tropicalisand indicate that nonmeiotic mechanisms drive ploidy changes in this prevalent human pathogen.

scholarly journals The Parasexual Cycle in Candida albicans Provides an Alternative Pathway to Meiosis for the Formation of Recombinant Strains

PLoS Biology ◽  
2008 ◽  
Vol 6 (5) ◽  
pp. e110 ◽  
Author(s):  
Anja Forche ◽  
Kevin Alby ◽  
Dana Schaefer ◽  
Alexander D Johnson ◽  
Judith Berman ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Alternative Pathway ◽  
Parasexual Cycle ◽  
Recombinant Strains

scholarly journals Extreme diversification driven by parallel events of massive loss of heterozygosity in the hybrid lineage of Candida albicans

Genetics ◽  
2020 ◽  
Vol 217 (2) ◽  
Author(s):  
Verónica Mixão ◽  
Ester Saus ◽  
Teun Boekhout ◽  
Toni Gabaldón
Keyword(s):  
Candida Albicans ◽  
Loss Of Heterozygosity ◽  
Type Strain ◽  
Taxonomic Classification ◽  
Hybrid Origin ◽  
Genomic Analyses ◽  
Candida Africana

Abstract Candida albicans is the most commonly reported species causing candidiasis. The taxonomic classification of C. albicans and related lineages is controversial, with Candida africana (syn. C. albicans var. africana) and Candida stellatoidea (syn. C. albicans var. stellatoidea) being considered different species or C. albicans varieties depending on the authors. Moreover, recent genomic analyses have suggested a shared hybrid origin of C. albicans and C. africana, but the potential parental lineages remain unidentified. Although the genomes of C. albicans and C. africana have been extensively studied, the genome of C. stellatoidea has not been sequenced so far. In order to get a better understanding of the evolution of the C. albicans clade, and to assess whether C. stellatoidea could represent one of the unknown C. albicans parental lineages, we sequenced C. stellatoidea type strain (CBS 1905). This genome was compared to that of C. albicans and of the closely related lineage C. africana. Our results show that, similarly to C. africana, C. stellatoidea descends from the same hybrid ancestor as other C. albicans strains and that it has undergone a parallel massive loss of heterozygosity.

scholarly journals Investigating the Transcriptome of Candida albicans in a Dual-Species Staphylococcus aureus Biofilm Model

2021 ◽  
Vol 11 ◽  
Author(s):  
Bryn Short ◽  
Christopher Delaney ◽  
Emily McKloud ◽  
Jason L. Brown ◽  
Ryan Kean ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Driving Forces ◽  
Transcriptional Profiling ◽  
Specific Interaction ◽  
Opportunistic Pathogen ◽  
Virulence Proteins ◽  
Biofilm Model ◽  
Upregulated Genes

Candida albicans is an opportunistic pathogen found throughout multiple body sites and is frequently co-isolated from infections of the respiratory tract and oral cavity with Staphylococcus aureus. Herein we present the first report of the effects that S. aureus elicits on the C. albicans transcriptome. Dual-species biofilms containing S. aureus and C. albicans mutants defective in ALS3 or ECE1 were optimised and characterised, followed by transcriptional profiling of C. albicans by RNA-sequencing (RNA-seq). Altered phenotypes in C. albicans mutants revealed specific interaction profiles between fungus and bacteria. The major adhesion and virulence proteins Als3 and Ece1, respectively, were found to have substantial effects on the Candida transcriptome in early and mature biofilms. Despite this, deletion of ECE1 did not adversely affect biofilm formation or the ability of S. aureus to interact with C. albicans hyphae. Upregulated genes in dual-species biofilms corresponded to multiple gene ontology terms, including those attributed to virulence, biofilm formation and protein binding such as ACE2 and multiple heat-shock protein genes. This shows that S. aureus pushes C. albicans towards a more virulent genotype, helping us to understand the driving forces behind the increased severity of C. albicans-S. aureus infections.

scholarly journals Bifidobacterium adolescentis shows potential to strengthen host defence against gastrointestinal infection via inhibition of the opportunistic pathogen Candida albicans and stimulation of human-isolated macrophages killing capacity in vitro

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Liviana Ricci ◽  
Joanna Mackie ◽  
Megan D. Lenardon ◽  
Caitlin Jukes ◽  
Ahmed N. Hegazy ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Bacterial Species ◽  
Opportunistic Pathogen ◽  
Limited Information ◽  
Human Gut ◽  
Bifidobacterium Adolescentis ◽  
Host Immune Responses ◽  
Opportunistic Fungal Pathogen ◽  
Antimicrobial Metabolites

The human gut microbiota enhances the host’s resistance to enteric pathogens via colonisation resistance, a phenomenon that is driven by multiple mechanisms, such as production of antimicrobial metabolites and activation of host immune responses. However, there is limited information on how individual gut bacterial species, particularly many of the dominant anaerobes, might impact the host’s defence. This study investigated the potential of specific human gut isolates to bolster the host’s resistance to infection. First, by antagonising the opportunistic fungal pathogen Candida albicans, and secondly, by modulating the killing capacity of human-isolated macrophages in vitro. Co-culturing C. albicans with faecal microbiota from different healthy individuals revealed varying levels of fungal inhibition. In vitro assays with a panel of representative human gut anaerobes confirmed that culture supernatants from certain bacterial isolates, in particular of Bifidobacterium adolescentis, significantly inhibited C. albicans growth. Mechanistic studies revealed that microbial fermentation acids including acetate and lactate, in combination with the associated decrease in pH, were strong drivers of this inhibitory activity. In the second in vitro assay, human-isolated macrophages were exposed to bacterial supernatants, and subsequently tested for their capacity to eliminate adherent-invasive Escherichia coli. Among the gut anaerobes tested, B. adolescentis was revealed to exert the strongest immunostimulatory and killing effect when compared to the unstimulated macrophages control. B. adolescentis is known to be stimulated by dietary consumption of resistant starch andmay therefore represent an attractive target for the development of probiotic and prebiotic interventions tailored to enhancethe host’s natural defences against infection.

Sign in / Sign up

Export Citation Format

Share Document