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The ultrastructure of Prototheca wickerhamii

K R Joshi, J B Gavin, E E Wheeler

    Mycopathologia
    |July 30, 1975
    PubMed

    Insights

    Prototheca wickerhamii spores exhibit distinct developmental stages. Resting spores develop cytoplasmic extensions, while vegetative spores proliferate rapidly, forming endospores within sporangia.

    Area of Science:

    • Microbiology
    • Cell Biology
    • Mycology

    Background:

    • Prototheca wickerhamii is an alga capable of causing infections in humans.
    • Understanding the life cycle and morphology of P. wickerhamii is crucial for developing effective treatments.

    Purpose of the Study:

    • To investigate the morphological and ultrastructural differences between resting and vegetative spores of Prototheca wickerhamii.
    • To elucidate the developmental processes involved in spore germination and proliferation.

    Main Methods:

    • Studying clinical isolates of Prototheca wickerhamii.
    • Utilizing electron microscopy (freeze-drying and fixation).
    • Employing phase-contrast light microscopy for observing growth in culture medium.

    Main Results:

    • Resting spores showed cytoplasmic extensions and sequestration before proliferation.
    • Vegetative spores rapidly grew and subdivided, forming up to 12 endospores within sporangia.
    • Proliferating spores had abundant endoplasmic reticulum and mitochondria, unlike resting spores rich in lipids and starch granules.

    Conclusions:

    • Prototheca wickerhamii exhibits distinct spore morphologies correlating with developmental stages.
    • The observed ultrastructural differences suggest unique metabolic and functional roles for resting and vegetative spores.
    • This study provides insights into the reproductive cycle of P. wickerhamii, relevant to its pathogenic potential.

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