1 zygomycetes
TRANSCRIPT
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The Zygomycetes
Elmer W. Koneman, M. D., USA
Manuela Anda Andrei, Romania
Romanian Society of Laboratory Medicine
2008 Congress -- Bucharest, Oct. 20 22
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The Zygomycetes
The Zygomyces are a group of fungi
that produce broad, aseptate hyphae and
bear spores within sack-like structures
called sporangia. In the perfect or
telomorphic form, they producezygospores (see photo).
They are widely distributed in soil,
dung, and vegetable matter. Humans
may become infected by inhaling spore-
contaminated dust (pulmonaryinfection), by ingesting contaminated
foodstuffs (GI infection) or by direct
inoculation of the skin (subcutaneous
infection).
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The Zygomycetes
Colonies of the Zygo-mycetes
grow rapidly over the entire
surface of the agar plate as
a gray-white, brown or
gray-brown, cottony orwooly colony, without a
distinct margin (lid lifter).
As the colony matures, the
mycelium may darken and
show a black pepper effectas a myriad of sporangia are
formed.
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The Zygomycetes
Microscopic Features
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MORPHOLOGY OF RHIZOPUS
Rapid border to border
growth on Sabouraud agar
Sproangiospores arise
singly or in groups
Rhizoids present at node
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ABSIDIA
Grows rapidly on Sabouraud agar
Sporangiophores branched
Rhizoids produced internodally
Sporangia pyriform, grayish brown togreenish beige
Columnella hemispherical
Apophysis distinctly conical Sporangiospores globose to cylindrical
and smooth
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MORPHOLOGY OF ABSIDIA
Grows rapidly on Sabouraud agarSporangiophores branched
Rhizoids produced internodally
Apophysis distinctly conical
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SYNCEPHALASTRUM
Grows rapidly on Sabouraud agar
Sporangiophores usually branched
and have swollen tips Cylindrical merosporangia produced
surrounding the swollen tip
Merospores produced within
merosporangia
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MORPHOLOGY OF
SYNCEPHALASTRUM
Sporangiophoresusually branched and
have swollen tips
Cylindrical
merosporangiaproduced surrounding
the swollen tip
Merospores produced
within merosporangia
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CUNNINGHAMELLA
Grows rapidly on Sabouraud agar
Conidiophores may be branched
Vesicles globose to subglobose
Sporangioles (conidia) are formed
on the surface of the vesicle
Conidia are echinulate
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MORPHOLOGY OF CUNNINGHAMELLA
Grows rapidly on
Sabouraud agar
Conidiophores may
be branched
Vesicles globose tosubglobose
Sporangioles
(conidia) are formed
on the surface of thevesicle
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MUCOR
Rapid growth on Sabouraud agar
Sporangiophores do not arise from stolon
Sporangiophores may be branched orunbranched
Rhizoids are not present
Sporangia globose, brownish to gray
Columella globose
Apophysis absent
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Rapid growth on Sabouraud agar
Sporangiophores do not arise from stolon
Sporangiophores may be branched or
unbranched
Rhizoids are not present
MORPHOLOGY OF MUCOR
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SAKSENAEA
Grows slowly and sporulates poorly on
Sabouraud agar
Rhizoids produced at base of sporangiophore
Sporangium is flask shaped, with long neck
Columella globose
Sproangiospores smooth and elongate
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MORPHOLOGY OF SAKSENAEA
Grows slowly and
sporulates poorly on
Sabouraud agar
Rhizoids produced at
base of sporangiophore
Sporangium is flask
shaped, with long neck
Columella globose
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REVIEW: ZYGOMYCETESCOLONY CHARACTERISTICS
Rapid growth in 3-5 days. Gray-
brown, wooly mycelium that fills the
Petri Dish. Pepper effect when
sporangia are produced.
MICROSCOPIC FEATURES
Hyphae are broad, ribbon-like,
irregular in diameter and devoid of
septations. Sporulation is via
production of sporangia.
LOOK FOR:
RHIZOIDS
PRESENT ABSENT
Nodal derivation of
sporangiophores.
Collapse of columella*******
RHIZOPUS
Branched
sporangio-
phhores; noapophysis
MUCOR
Spherical columella
and merosporangia
*******
SYNCEPHAL-
ASTRUM
Circular curve of
sporangiophores
*****CIRCINELLA
Large
spherical
sporangioles
******
CUNNING-
HAMELLA
Internodal derivation of
sporangiophores.
Apophysis present.
*******
ABSIDIA
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QUESTIONS/COMMENTS?