Debaryomyces hansenii (Candida famata), a Rare Human Fungal Pathogen Often Misidentified as Pichia guilliermondii (Candida guilliermondii)

Microflora in wound sites of preharvest maize (including bacteria, yeasts, and filamentous fungi) may play a role in attracting insects to maize plants and may also interact with growth and mycotoxin production by filamentous fungi. As little data are available about the yeasts occurring on maize from the U.S. corn belt, samples of milled maize from experimental plantings at the University of Illinois River Valley Sand Field were analyzed. Yeast counts showed slight yearly fluctuation and varied between 3.60 and 5.88 (log cfu/g maize). The majority of the yeasts were Candida guilliermondii (approximately 55%), Candida zeylanoides (24 %), Candida shehatae (11%), and Debaryomyces hansenii (3%). Also present were Trichosporon cutaneum, Cryptococcus albidus var. aerius, and Pichia membranifaciens. The occurrence of killer yeasts was also evaluated. Killer yeasts were detected in maize for the first time and were identified as Trichosporon cutaneum and Candida zeylanoides. These were able to kill some representative yeasts isolated from maize, including Candida guilliermondii, Candida shehatae, and Cryptococcus albidus var. aerius. Other maize yeasts (Candida zeylanoides, Debaryomyces hansenii, Pichia membranifaciens) were not affected. The majority of yeasts found on maize were unable to ferment its major sugars, i.e., sucrose and maltose. Some (e.g., Candida zeylanoides) were not even able to assimilate these sugars. The importance of these properties in relation to insect attraction to preharvest ears of maize is discussed.Key words: corn, maize, yeast, killer.

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Pmt-Mediated O Mannosylation Stabilizes an Essential Component of the Secretory Apparatus, Sec20p, in Candida albicans

Eukaryotic Cell ◽

10.1128/ec.3.5.1164-1168.2004 ◽

2004 ◽

Vol 3 (5) ◽

pp. 1164-1168 ◽

Cited By ~ 22

Author(s):

Yvonne Weber ◽

Stephan K.-H. Prill ◽

Joachim F. Ernst

Keyword(s):

Endoplasmic Reticulum ◽

Candida Albicans ◽

Fungal Pathogen ◽

Wild Type ◽

Rapid Degradation ◽

Vesicle Traffic ◽

Human Fungal Pathogen ◽

Low Levels ◽

Lumenal Domain ◽

Secretory Apparatus

ABSTRACT Sec20p is an essential endoplasmic reticulum (ER) membrane protein in yeasts, functioning as a tSNARE component in retrograde vesicle traffic. We show that Sec20p in the human fungal pathogen Candida albicans is extensively O mannosylated by protein mannosyltransferases (Pmt proteins). Surprisingly, Sec20p occurs at wild-type levels in a pmt6 mutant but at very low levels in pmt1 and pmt4 mutants and also after replacement of specific Ser/Thr residues in the lumenal domain of Sec20p. Pulse-chase experiments revealed rapid degradation of unmodified Sec20p (38.6 kDa) following its biosynthesis, while the stable O-glycosylated form (50 kDa) was not formed in a pmt1 mutant. These results suggest a novel function of O mannosylation in eukaryotes, in that modification by specific Pmt proteins will prevent degradation of ER-resident membrane proteins via ER-associated degradation or a proteasome-independent pathway.

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The 5’ untranslated region of theEFG1transcript promotes its translation to regulate hyphal morphogenesis inCandida albicans

10.1101/328948 ◽

2018 ◽

Author(s):

Prashant R. Desai ◽

Klaus Lengeler ◽

Mario Kapitan ◽

Silas Matthias Janßen ◽

Paula Alepuz ◽

...

Keyword(s):

Candida Albicans ◽

Fungal Pathogen ◽

Regulatory Mechanisms ◽

Untranslated Regions ◽

Regulatory Sequence ◽

Transcriptional Level ◽

Human Fungal Pathogen ◽

Hyphal Morphogenesis ◽

Cellular Morphogenesis ◽

Incandida Albicans

ABSTRACTExtensive 5’ untranslated regions (UTR) are a hallmark of transcripts determining hyphal morphogenesis inCandida albicans.The major transcripts of theEFG1gene, which are responsible for cellular morphogenesis and metabolism, contain a 5’ UTR of up to 1170 nt. Deletion analyses of the 5’ UTR revealed a 218 nt sequence that is required for production of the Efg1 protein and its functions in filamentation, without lowering the level and integrity of theEFG1transcript. Polysomal analyses revealed that the 218 nt 5’ UTR sequence is required for efficient translation of the Efg1 protein. Replacement of theEFG1ORF by the heterologous reporter geneCaCBGlucconfirmed the positive regulatory importance of the identified 5’ UTR sequence. In contrast to other reported transcripts containing extensive 5’ UTR sequences, these results indicate the positive translational function of the 5’ UTR sequence in theEFG1transcript, which is observed in context of the nativeEFG1promoter. The results suggest that the 5’ UTR recruits regulatory factors, possibly during emergence of the native transcript, which aid in translation of theEFG1transcript.IMPORTANCEMany of the virulence traits that makeCandida albicansan important human fungal pathogen are regulated on a transcriptional level. Here we report an important regulatory contribution of translation, which is exerted by the extensive 5’ untranslated regulatory sequence (5’ UTR) of the transcript for the protein Efg1, which determines growth, metabolism and filamentation in the fungus. Presence of the 5’ UTR is required for efficient translation of Efg1, to promote filamentation. Because transcripts for many relevant regulators contain extensive 5’ UTR sequences, it appears that virulence ofC. albicansdepends on the combination of transcriptional and translation regulatory mechanisms.

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Epigenetic dynamics of centromeres and neocentromeres in Cryptococcus deuterogattii

PLoS Genetics ◽

10.1371/journal.pgen.1009743 ◽

2021 ◽

Vol 17 (8) ◽

pp. e1009743

Author(s):

Klaas Schotanus ◽

Vikas Yadav ◽

Joseph Heitman

Keyword(s):

Dna Methylation ◽

Transposable Element ◽

Fungal Pathogen ◽

Fusion Partner ◽

Epigenetic Memory ◽

Chromosome Fusion ◽

Human Fungal Pathogen ◽

Chromosome Fusions ◽

The Impact ◽

Active Centromere

Deletion of native centromeres in the human fungal pathogen Cryptococcus deuterogattii leads to neocentromere formation. Native centromeres span truncated transposable elements, while neocentromeres do not and instead span actively expressed genes. To explore the epigenetic organization of neocentromeres, we analyzed the distribution of the heterochromatic histone modification H3K9me2, 5mC DNA methylation and the euchromatin mark H3K4me2. Native centromeres are enriched for both H3K9me2 and 5mC DNA methylation marks and are devoid of H3K4me2, while neocentromeres do not exhibit any of these features. Neocentromeres in cen10Δ mutants are unstable and chromosome-chromosome fusions occur. After chromosome fusion, the neocentromere is inactivated and the native centromere of the chromosome fusion partner remains as the sole, active centromere. In the present study, the active centromere of a fused chromosome was deleted to investigate if epigenetic memory promoted the re-activation of the inactive neocentromere. Our results show that the inactive neocentromere is not re-activated and instead a novel neocentromere forms directly adjacent to the deleted centromere of the fused chromosome. To study the impact of transcription on centromere stability, the actively expressed URA5 gene was introduced into the CENP-A bound regions of a native centromere. The introduction of the URA5 gene led to a loss of CENP-A from the native centromere, and a neocentromere formed adjacent to the native centromere location. Remarkably, the inactive, native centromere remained enriched for heterochromatin, yet the integrated gene was expressed and devoid of H3K9me2. A cumulative analysis of multiple CENP-A distribution profiles revealed centromere drift in C. deuterogattii, a previously unreported phenomenon in fungi. The CENP-A-binding shifted within the ORF-free regions and showed a possible association with a truncated transposable element. Taken together, our findings reveal that neocentromeres in C. deuterogattii are highly unstable and are not marked with an epigenetic memory, distinguishing them from native centromeres.

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mSphere of Influence: the Power of Yeast Genetics Still Going Strong!

mSphere ◽

10.1128/msphere.00647-19 ◽

2019 ◽

Vol 4 (5) ◽

Author(s):

Felipe H. Santiago-Tirado

Keyword(s):

Genetic Analysis ◽

Fungal Pathogen ◽

Cell Biology ◽

Genetic Manipulation ◽

Chemical Genetics ◽

Yeast Genetics ◽

Content Type ◽

Human Fungal Pathogen ◽

Link Type ◽

Fungal Meningitis

ABSTRACT Felipe Santiago-Tirado studies the cell biology of cryptococcal infections. In this mSphere of Influence article, he reflects on how the papers “Systematic Genetic Analysis of Virulence in the Human Fungal Pathogen Cryptococcus neoformans” (https://doi.org/10.1016/j.cell.2008.07.046) and “Unraveling the Biology of a Fungal Meningitis Pathogen Using Chemical Genetics” (https://doi.org/10.1016/j.cell.2014.10.044) by the Noble and Madhani groups influenced his thinking by showcasing the various modern applications of yeast genetics in an organism where genetic manipulation was difficult.

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Chromosome-Level Genome Assembly of a Human Fungal Pathogen Reveals Synteny among Geographically Distinct Species

mBio ◽

10.1128/mbio.02574-21 ◽

2022 ◽

Author(s):

Mark Voorhies ◽

Shirli Cohen ◽

Terrance P. Shea ◽

Semar Petrus ◽

José F. Muñoz ◽

...

Keyword(s):

North America ◽

South America ◽

Genome Assembly ◽

Fungal Pathogen ◽

Distinct Species ◽

Significant Morbidity ◽

Dimorphic Fungi ◽

Human Fungal Pathogen ◽

America South ◽

Chromosome Level

Histoplasma species are dimorphic fungi causing significant morbidity and mortality worldwide. These fungi grow as mold in the soil and as budding yeast within the human host. Histoplasma can be isolated from soil in diverse regions, including North America, South America, Africa, and Europe.

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