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Phylum:ascomycota

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Title: Slide 1 Author: pcg Last modified by: CiTC Created Date: 7/29/2009 5:14:24 PM Document presentation format: On-screen Show (4:3) Company: Other titles – PowerPoint PPT presentation

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Title: Phylum:ascomycota


1
Phylumascomycota
  • General characters
  • Mycelium is septated and branched except in
    yeasts (unicellular).
  • Complete absence of flagellated cells.
  • Cell wall contain large amount of chitin and less
    cellulose.
  • Cell wall contain large amount of chitin and less
    cellulose.
  • Harmful or parasities,causing
    several diseases to plantand human
  • Saprophytes and may
    produce useful enzyemes and vitamins.

2
  • 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.

3
  • 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.

4
  • 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

5
Ascus formation
6
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7
Subclassprotoascomycetes. Order
Endomycetales. Family Saccharomycetaceae. Sacchar
omyces 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.

8
Reproduction
  • 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.

9
  • 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.

10
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.

11
  • Subclass Euascomycetes
  • Series Plectomycetes
  • Order Asergillales
    Order Erysiphales
  • (Asci are scattered)
    family Erysiphaceae
  • Family Aspergillaceae
  • Ex Aspergillus
  • Penicillium

(asci are arranged)
12
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 (18-19)enzymes including
    cellulases xylanases amaylases pectinases
    inulinases phylase.

13
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.

14
Asexual reproduction
  • It takes place by means of conidia ,which are
    formed in chains externally on conidiophores.
  • When asexual reproduction takes place a certain
    cell of the hyphae become larger and thick
    walled(foot cell).
  • From each foot cell a vertical, non-septated
    conidiophore arise each conidiophore ends with a
    vesicle.
  • 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.

15
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 Gve bacteria).
  •  
  • Conidiophores are spetated and branched.

16
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.

17
  • the order Erysiphales is classified as follow
  • FamilyErysiphales
  • Subfamilyphyllactinae
    sub familyErysipheae
  • conidia
  • Are solitary
  • Phyllactinea
    leivellula
  • Conidia more one
    contain more than one ascus appendages
    are normal myceloid
  • Ascus ,appendages with
  • Bulbous base and pointed tips

18
  • sub familyErysipheae
  • Erysiphe
    uncinulla
  • More than One ascus.
    More than one ascus
  • Normal appendges
    curved appendeges

  • Sphaerotheca
  • have one
    ascus
  • normal
    appendages

19
SubclassEuascomycetes Seriespyrenomycetes 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.

20
SubclassEuascomycetes SeriesDiscomycetes
  • 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.
  • orderPezizales
  • FamilyPezizaceae
  • Peziza
    sclerotinia morchella
  • Cup fungi cause rot of onion
    sponge mushroom
  • Saprophytes on animal
  • dungs.
    saprophytes grow on
  • And decaying wood
    cluster in soil rich in
  • Form large apothecium.
    Organic substances

21
SubclassEuascomyctes SeriesLoculoascomycetes
  • 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
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