World of Dermatophytes: A Pictorial

Glossary

[Media & Methods] [Case Study]

Definitions of Terms used in
Laboratory Identification of Fungi

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Aerial hyphae/mycelium

hyphae above the agar surface

Alternate

used to describe arthroconidia in a chain separated by cells which break down to release the conidia

Anamorph

asexual, ”imperfect” reproductive stage

Annellide

a conidiogenous cell which elongates and leaves a scar ring with the production of each conidium

Anthropophilic

dermatophytes that are restricted to human hosts

Antler hyphae

hyphae terminating in broad irregular branches resembling antlers

Arthroconidium

conidia formed in chains by the breaking up of a hyphae at the point of septation. The resulting cell may be rectangular or barrel shaped and thick or thin walled, depending on the genus.

Ascocarp

fruiting structure of the sexual reproductive stage with internally formed asci

Ascospore

sexual spore produced in a sac-like structure known as an ascus. Commonly there are 4 to 8 ascospores in an ascus.

Ascus

a sac like structure that contains ascospores

Aseptate

hyphae without cross walls. Characteristic of Zygomycetes.

Biseriate

a vesicle in Aspergillus bearing two layers of cells - metulae and phialides

Blastoconidium

conidium formed by budding along a hyphae, pseudohyphae, or single cell, as in the yeasts.

Chlamydospore

thick-walled somewhat resistant structure formed at end of hyphae (terminal) or in the middle of hyphae (intercalary). Also a vesicle formed by Candida albicans.

Clamp connection

small, curved hyphal outgrowth at a septum forms a looped bridge between two adjacent cells. Formed only in Basidiomycetes.

Clavate

club-shaped

Cleistothecium

round or oval sexual fruiting body without an opening and with asci irregularly dispersed in centre

Collarette

flared or straight-sided cell wall remnant at the tip of a phialide or base of a columella

Columella

dome-shaped top of a sporangiophore, contained in a sporangium

Conidiogenous

structure that produces conidia

Conidioma

an asexual, conidium-bearing structure

Conidiophore

specialized hyphal structure that serves as a stalk on which conidia are formed

Conidium (pl. conidia)

asexual reproductive structure that forms externally on the side or the end of the hyphae or conidiophore

Cottony texture

high dense aerial mycelium

Dematiaceous

hyphae, conidia, or spores that are brown to black

Denticle

small hair-like projection on which a solitary conidium is formed

Dichotomous

branching of hyphae into two equal branches that are each equal in diameter to the hyphae from which they originated

Dimorphic

having two distinct forms. Usually grow filamentously under environmental conditions and convert to special parasitic form (often yeast) in vivo.

Ectothrix

Ectothrix infection around the outside of the hair shaft

Endospore

spore produced within the spherule of Coccidioides immitis

Endothrix

Endothrix infection with arthroconidia within the hair shaft

Exudate

droplets of liquid on the surface of a colony

Favic chandeliers

hyphae terminating in broad irregular branches resembling antlers. Typical of Trichophyton schoenleinii.

Faviform

blunt, branched hyphal ends

Foot cell

in Aspergillus, a hyphal cell at the conidiophore base;
in Fusarium, the sharply angled end of a macroconidium where it attaches to a conidiophore

Geophilic

usually recovered from soil, occasionally infect humans and animals

Glabrous

smooth; without or almost without aerial hyphae.

Globose

round

Granular

dense conidia on surface of colony; resembling sugar granules

Hulle cell

refractile, thick-walled cell, varying in shape, which occurs in some Aspergillus species

Hyaline

not pigmented, colourless.

Hyphae

septate or aseptate filament of a fungus; many together compose the mycelium.

Intercalary

forming in the middle of a hyphae

Macroconidium

Macroconidia larger of two types of conidia produced by the same organism;
usually is multicelled

Metulae

branch upon which a conidiogenous cell is borne; on a vesicle in Aspergillus or terminal branches in Penicillium

Microconidium

Microconidia
the smaller of two types of conidia produced by the same fungus

Moniliform

hyphae with swellings at regular intervals like a string of beads

Muriform

having both transverse and longitudinal septa

Nodular bodies

knot of twisted hyphae

Onychomycosis

infection of the nails

Ostiole

opening in wall of fruiting body through which conidia are released

Ovoid

egg-shaped

Pectinate

Pectinate hyphae hyphal ends which have protuberances resembling a comb

Pedicel

short filament which attaches a conidium to the hyphae

Penicillus

brush-like conidiogenous structure with 1-3 levels of branches called metulae and a terminal phialide

Perithecium

flask-shaped or rounded fruiting body with opening (ostiole) and asci arranged at base of structure

Phialide

conidiogenous cell which neither elongates or enlarges; may have a cup-shaped opening or collarette

Powdery texture

profusion of conidia on surface of colony; resembles flour

Pseudohyphae

chains of cells formed by budding that, when elongated, resemble true hyphae; they differ from true hyphae by being constricted at the septa, forming branches that begin with a septation, and having terminal cells smaller than the other cells.

Pycnidium

conidioma in which conidiogenous cells line the interior cavity and are released through an opening or ostiole; formed by Coelomycetes

Pyriform

pear-shaped or teardrop-shaped

Racquet hyphae

hyphae with club-shaped cells, the larger end of one cell being attached to the smaller end of an adjacent cell.

Reflexive branching

branches that grow forward and backward at acute angles to the hyphae

Rhizoid

root-like, branched hyphae

Rugose topography

colony in which furrows radiate out from the centre

Sclerotium

hyphae closely interwoven and cemented together into a hard resistant body

Scotch Tape Mount

The scotch tape mount is used for examining the microscopic structures of filamentous fungi. With forceps pick up a piece of clear, transparent tape and touch the surface of the colony. Place the tape onto a drop of mounting media on a slide; add another drop and a coverslip. Examine with a phase contrast microscope.

Septate

Septate hyphae having cross walls

Sessile

Sessile teardrop microconidium arising from side of hyphae or conidiogenous cell

Spherule

large, round structure containing endospores; characteristic of Coccidioides immitis in infected host material under direct microscope examination. Spherules do not grow on routine artificial mycology media.

Spiral hyphae

Spiral hyphae hyphae forming coiled or corkscrew-like turns

Sporangiophore

specialized hyphal branch or stalk bearing a sporangium

Sporangiospore

asexual spore produced in a sporangium

Sporangium

closed sac-like structure in which asexual spores (sporangiospores)are formed. The sporangium is borne on a stalk known as the sporangiophore.

Stolon

horizontal, aerial (runner) hyphae which gives rise to rhizoids and sporangiophores

Sympodial

a succession of conidia formed on opposite sides of hyphal stalk so that the axis pushes past the terminal conidium to form a zig-zag structure

Teleomorph

sexual reproductive stage of a fungus

Thallus

fungal colony, mycelium

Truncate

conidium with a scar flattened off at the point of attachment

Umbonate topography

colony with centre button-shaped elevation

Uniseriate

in Aspergillus, a vesicle bearing a single layer of phialides

Velvety texture

low aerial mycelium with smooth nap, as in velvet cloth

Verrucose topography

colony furrowed or convoluted

Verticil

group of conidiogenous cells radiating out from a single point like spokes in a wheel

Vesicle

inflated end of a conidiophore or sporangiophore

Woolly texture

colony with high aerial mycelium which appears slightly matted

Yeast-like colony

soft, pasty, smooth colony; usually without filamentous growth

Zoophilic

found primarily in animals, occasionally infect humans