pseudohyfer

Pseudohyfer, more commonly referred to as pseudohypha, is a fungal growth form produced by certain yeasts such as Candida species and some Saccharomyces strains. It consists of elongated, budding yeast cells that remain attached after division, forming a chain-like structure with constrictions at the sites where cells connect. This gives a filamentous appearance that is distinct from true hyphae.

Morphologically, pseudohyphae are characterized by constricted septa between cells and relatively short, elongated cells. In contrast, true hyphae have continuous cytoplasm, parallel walls, and fewer or no constrictions at junctions. Pseudohyphae can arise when yeast cells undergo a switch from unicellular budding to a filamentous growth mode, typically in response to environmental cues such as nutrient limitation, temperature changes, or specific signaling pathways.

Formation of pseudohyphae is a part of the broader morphological plasticity seen in several pathogenic yeasts. In Candida albicans, for example, the yeast-to-pseudohypha transition is one of several forms the organism can adopt under different conditions, and it can be accompanied by or precede the development of true hyphae in some contexts. Regulatory pathways implicated in these switches include the cAMP-PKA and MAPK signaling cascades, which integrate environmental signals to modulate growth form.

Clinical and diagnostic relevance arises because pseudohyphae can be observed in tissue samples or clinical specimens and are associated with the pathogenic potential of opportunistic yeasts. They are typically detected by light microscopy using appropriate stains (for example, Gomori methenamine silver or periodic acid–Schiff).

Notes: the term pseudohyfer is commonly a misspelling or variant of pseudohypha; the preferred term in most literature is pseudohypha.