Phylum:ascomycota
• General characters:
1. Mycelium is septated and branched except in yeasts
(unicellular).
2. Complete absence of flagellated cells.
3. Cell wall contain large amount of chitin and less
cellulose.
4. Cell wall contain large amount of chitin and less
cellulose.
5.
Harmful or parasities,causing several
diseases to plantand human
Saprophytes and may produce useful
enzyemes and vitamins.
6. Asexual reproduction bu non motile conidia,which are
produced on a specialized hypae called conidiophore.
7. Sexual reproduction produse ascospores in ascus(sac
like structure) usually 8 spores.
• Ascocarp:
More than one ascus or even one may enclosed in a
fruiting body called ascocarp which may be :
Cleistothecium
perithecium
apothecium
Cleistothecium:
It is globose ,which has no natural openinig the
cleistothecium wall may not covered with out growths
(appendages).
The asci may be arranged in hymenial layer or scatter
Asci are liberated by disintegration of the cleistothecial
wall.
• perithecium:
It is a flask shaped ascocar with an
apical opening(ostiole).
The asci and paraphysis are arranged
in a hyminial layer, ascospores libareted from
the ostiole.
• apothecium:
It is a cup or saucer shaped
ascocarp the asci and paraphsis ara arranged
on the upper surface in a hymenial layer
Ascus formation
Class:
ascomycetes
sub class:
Protoascomysetes
*the asci are nacked
not enclosed in
ascocarp.
Order:
endomycetales
Family:Saccharomy
cetaceae
ex:Candida albicans
Plectomycetes
*asci are
enclosed in a
cleistothecium
Subclass:
Euascomysetes
*asci or ascus
enclosed in an
ascocarp.
Order:taphrinales
family:Taphrinacea
e
ex: Taphrina
deformans
Discomycetes
*asci are
enclosed in
apothecium
Pyrenomycetes
*asci enclosed in
aperithecium
Subclass:protoascomycetes.
Order: Endomycetales.
Family: Saccharomycetaceae.
Saccharomyces cervisae.
• Vegetative structure and economic importance:
yeasts are unicellular organisms, oval or spherical shaped,
live in colonies with white or yellow, and they are dimorphic.
 Dimorphism:
Is the ability of an organism to grow either
unicellular or filamentous according to surrounding condition.
Ex:
Yeast
at 370 c grow as unicellular.
at 240 c grow as mycelia
• Saccharomyces has avery important role in industries such as
fermentation beaking production of vitamins and alchols.
Reproduction:
1. budding:
•
•
•
•
At favorable conditions (food is abundant) the nucleus of
the yeast cell divides mitotically and a bud is formed from the
wall of
mother cell.
Then one nucleus passes into this bud with a part of the
cytoplasm then this bud separated from the mother cell to give
daughter
cell.
Some times the bud itself may give another bud and the bud
do not detached from the mother cells resulting in the
fromation of
Achain of bud called pseudomycelium.
• fission:
Parent cell elongates and its nucleus divides to produce
two daughter nuclei , then a wall is formed in the middle of the
cell from two new cell.
sexual reproduction
• It takes place when food is exhausted ,it occurs by conjugation
between two vegetative cells the process is called hologamy
,this result in the formation of diploid zygot cell which function
directly as an ascus and produce ascospores.
• 1-Haplopiontic life cycle.
2-diplobiontic life cycle.
3- haplodiplobiontic life cycle.
• Candid albicans is ahuman pathogen live in mouth, vagina and
cause in young candidomycosis which may treared by
amphotrosin c.
• Subclass: Euascomycetes
• Series: Plectomycetes
Order: Asergillales
(Asci are scattered)
Family: Aspergillaceae
Ex: Aspergillus
Penicillium
Order: Erysiphales
family: Erysiphaceae
(asci are arranged)
Aspergillus
•
•
•
•
•
•
*Aspergillus is a widely distrisbuted genus, most are
saprophytes on dead organic materials(fruits,jams ,leather,
wood,……..) on orange, aspergillus form blue mould.
On otherhand some species are parasites.
*A.flavus,A.fumigtus and A.niger cause diseases to human and
animals known asperilloses also they may cause disease for
human ear called otomycosis.
A.flavus produce mycotoxins.
A. fumigatus give fumes which may contaminate the
enviroment and cause respiratory tract infections of human.
A.niger
is very important for industry it produce about (1819)enzymes including: cellulases xylanases amaylases
pectinases inulinases phylase.
vegetative structure:
• The vegetative structure of Aspergillus is
branched and septated mycelia which may:
Substarte mycelium:
Responsible for fixation and nutrient up take.
Aerial mycelium:
Appeare above and carrying reproductive
organs.
Asexual reproduction:
• It takes place by means of conidia ,which are
formed in chains externally on conidiophores.
1. When asexual reproduction takes place a certain cell of the
hyphae become larger and thick walled(foot cell).
2. From each foot cell a vertical, non-septated conidiophore
arise each conidiophore ends with a vesicle.
3. A large number of nuclei and cytoplasm migrate into the
vesicle.
4. From each vesicle a tubular outgrowths are
produced(sterigmata).
(sterigmata may be used in identification of Aspergillus).
5. From the tips of sterigmata a chain of conidia are formed.
Penicillium
• Pencicillium is a saprophytic fungus known as(blue or
green mould),it live on several organic
substrates(fruits, vegetables,bread,……………….).
• Vegetative mycelium is branched and septated.
• Some species such as P. chrysogenum produce the
antibiotic pencillin(break bonds between
peptidoglycan in the cell wall of G+ve bacteria).
• Conidiophores are spetated and branched.
Order: Erysiphales
Family: Erysiphaceae
• members of this family are :
• Obligate parasites,cause powdery mildew disease.
• Produce their asci arranged on hymenial layer inside a
cleistothecium.
• Depending on:
The aggregation of conidia on conidiophores.
Number of asci inside the cleistothecium.
Type of appendages.
*the order Erysiphales is classified as follow
Family:Erysiphales
Subfamily:phyllactinae
*conidia
Are solitary
Phyllactinea
Conidia more one
ascus appendages
Ascus ,appendages with
Bulbous base and pointed tips
sub family:Erysipheae
leivellula
contain more than one
are normal myceloid
• sub family:Erysipheae
Erysiphe
uncinulla
More than One ascus.
Normal appendges
More than one ascus
curved appendeges
Sphaerotheca
have one ascus
normal appendages
Subclass:Euascomycetes
Series:pyrenomycetes
Family:clavisiptaceae.
• This group of fungi profuce their ascus in a perithecium.
• Members of this fungi are parasites on graminae and cause
ergot disease.
• The infected grains contain atoxic substance called ergotamine
• This substance has avascoconstrictor effect on the blood
vessels and may cause hair falling.
Subclass:Euascomycetes
Series:Discomycetes
• This fungi produce asci in an open ascocarp(apothecium).
• The apothecium is cup shaped so these fungi may known as
cup fungi.
• The asci are arranged on a hymenial layer.
order:Pezizales
Family:Pezizaceae
Peziza
sclerotinia
Cup fungi
cause rot of onion
Saprophytes on animal
dungs.
And decaying wood
Form large apothecium.
morchella
sponge mushroom
saprophytes grow on
cluster in soil rich in
Organic substances
Subclass:Euascomyctes
Series:Loculoascomycetes
• This group of fungi are form their asci in ascostroma .
• The ascus has two walls so it called bitunicate ascus
• The inner called endotunica extensible and thin
• The outer called exotunica inextensible and thick