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Mycology Myco = Fungus logy = Study.

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Presentation on theme: "Mycology Myco = Fungus logy = Study."— Presentation transcript:

1 Mycology Myco = Fungus logy = Study

2 إعــــــداد الطــــــــــلاب
سوزان عبدالحكم إيمان ناصرأحمـد أسماء عبــــــادة أحمــد سمير فتحي محمد ماهر محمود أحمد محمــد نجيب محمد إبراهيم المهدي تحت إشراف الدكتور/ عبدالدايم أبوالفتوح شريف قسم النبات – كلية العلوم – جامعة المنصورة (2008 – 2009)

3 Introduction Mycology : is a branch of science which concentrate on studying fungi. General Characters Nutrition Economic Importance Reproduction Classification

4 1- General Characters Eukaryotic Organisms (i.e true nucleus)
Non-Vascular Organisms Non-motile except few fungi Vegetative body may be: unicellular Filamentous Septated Non-Septated

5 Like plants, have alternation of generation
cell wall similar in structure of plant but differ in chemical composition Plant C.W Cellulose + lignin Fungi C.W Chitin Fungi are Heterotrophic organisms Growth by apical elongation of hyphal tip Food stored as glycogen but plant as starch Cell membrane in animal cholesterol in Fungi ergosterol

6 Fungi produce exoenzymes to digest food then ingest it
Reproductive Structures are differentiated from somatic structures Cytoplasmic ultrastructures similar to plant cells , but differ in kinds or organelles

7 Most fungi have very small nuclei , with little repetative DNA
Reproduction Sexual Asexual Vegetative

8 2- Nutrition in fungi Saprophytes Parasites Symbiotic
Saprophytes : 1- use non - living organic materials 2- important in recycling C,N and essential mineral nutrients

9 Parasites : 1- use organic materials from living organisms , causing diseases to them 2- they have a wide range of hosts as diatoms , fungi , plants ,animals , human . Symbiotic : 1- fungi that have a beneficial symbiotic relationship with other living organisms Ex : Mycorrhizae Lichens Commensalism

10 Mycorrhizae It is associations of fungi with plants roots
Types of Mycorrhizae : Endomycorrhizae Ectomycorrhizae Fungus doesn’t form sheath around the roots Fungus penetrate the cells of cortex without penetrating the cell membrane Ex. Zygomycota Fungus form a sheath around the root with hyphal grow through the soil which increase the surface area Fungus penetrate between cells of cortex Ex. Basidiomycota and Ascomycota

11 Lichens Commensalism Lichens uses
Symbiotic relation between fungus and algae Most are Ascomycota ,few are Basidiomycota Lichens uses Lichens break down rocks into soil Food source for some animals Source for dyes , tweed Commensalism One organism uses another to get better position No physiological interaction Maybe for photosynthesis or reproductive advantages

12 3- Economic Importance Harmful Useful
Cause human,animal, plant disease directly or their toxins Cause rot of food Can destroy manufactured good Useful Yeast bread & brew Antibiotics penicillin Steroids and Hormons Stinky Cheeses Source of organic compost Source of food Experimental importance as: Easily cultured, take little space, multiply rapidly, short life cycle Study metabolic pathways Study growth, development, differentiation Microbial assay of vitamins and amino acids Study mechanism of cell division and development to

13 Types of reproduction:
Sexual Asexual vegetative a. Sexual: - Involve the union of two compatible nuclei with a subsequent meiotic division - All sexual fungal life cycles consists of : plasmogamy karyogamy meiosis reduced to Cell fusion Nuclear fusion N N

14 Nuclei or Gametes Zygote (2n) (n) fungal life cycle Plasmogamy
Meiosis Nuclei or Gametes (n) Zygote (2n) fungal life cycle Plasmogamy (n) karyogamy (n+n) 1n Haploid number of chromosomes 2n Diploid number of chromosomes

15 The two fusing gametes may be:
1. Morphologically the same, they are called isogametes and the process of fertilization is called isogamous 2. Differ in size and structure, they are called heterogametes and the process of fertilization is called heterogamous Anisogamy oogamy The fussing gametes are morphologically the same but differ in size .Differ in everything .As between antheridium and oogonium or ascogonium antheridium

16 Gametangial copulation
Methods of plasmogamy: Gametangial contact Gametangial copulation Spermatization Gametangial contact: oogonium antheridium The male and female gametangia come into contact with each other, and the male nuclei from male antheridium are transferred into the female oogonium either; through egg a pore at the point of their contact or through a tube called fertilization tube arise from antheridium to oogonium, then plasmogamy & karyogamy occur inside the oogonium.

17 Gametangial copulation:
Fusion occurs between the entire content of the two gametangia by one of the following ways: a. Contents of one gametangium is transferred to the other through a pore at the point of their contact suspensor b. The content of the two + - gametangia fuse by the dissolution of their contact walls, leading to the formation of a common cell, in which the content of the two gametangia mix

18 Spermatization spermatia Occurs by the transfer of spermatia (unicellular – non motile male cells) by wind, water or insects to a special receptive hyphae on the female gametangium Receptive hyphae Notes The sex organs are called gametangia which may be differentiated into antheridium & oogonium and produce different sex gametes Some fungi are: homothalic (single mycelium reproduce sexually), others are heterothalic (two mycelia reproduce sexually)

19 b. Asexual: Asexual reproduction takes place by spores
Fungal spores are variable in: colour, size, surface: smooth rough spiny spherical needle pear shape: kidney ovoid spindle fusiform unicellular bicellular number of cells: multicellular arrangement: solitary chain cluster

20 According to manner by which spores are borne on the mycelium, there are two types:
Sporangiospores Conidia Sporangiospores: Asexual spores produced internally in a sac like structure called sporangium, borne on specialized hyphae called sporangiophore Sporangiospores may be: motile or non motile Motile Called zoospores The sporangia called zoosporangia They may have one or two flagella similar or They may fixed anteriorly or posteriorly or different (tinsel, whiplash) ventrally

21 Non motile Called a planospores Are disseminated by wind current

22 Conidia: Asexual non motile spores produced
externally on a special hyphae called conidiophore Conidia may formed singly (phytophthora) or in chain (penicillium) Conidiophores may be free from each other or aggregated to form the following compound structures pycnidium acervulus sporodocium

23 C. Vegetative: Fragmentation: The mycelium breaks up into
fragments, each fragment germinate into a new individual under favorable conditions 2. Oidia: The hyphae break up into small oval or rounded segments hyphae 3. Chlamydospore: Certain cells of hyphae become thick walled chlamydospore

24 4. Fission: In unicellular true fungi (Yeast), the vegetative cell splits into two equal daughter cells 5. Budding: As in Yeast, the vegetative cell produces a small out growth (bud) which is finally separated from the mother cell and form a new cell

25 Some definitions 6. Sclerotia: Hardened & resistant bodies
Sporangium: Asexual sac like structure, carried on special hyphae called sporangiophores containing several sporangiospores Sporangiospores: Asexual spores produced internally in a sac like structure called sporangium, borne on specialized hyphae called sporangiophore.

26 Conidia: Asexual non motile spores produced externally on a special hyphae called conidiophore Conidiosporangium: Asexual spores, which may be germinate directly as conidium or sporangium (give several spores which release and germinates)

27 5- Classification of fungi
Based on: Somatic structure Sexual reproduction Somatic structure: Plasmodium Rudimentary mycelium Filamentous Unicellular (Yeast)

28 2.Sexual reproduction: Kingdom: Mycota Plasmodium:
Fungi are classified as following: Kingdom: Mycota Subkingdom: Myxomycota Subkingdom: Eumycota (Slime moulds) (True Moulds) The vegetative phase is plasmodium Classified according to the method of sexual reproduction Plasmodium: Slimy, naked, multinucleate mass of protoplasm

29 Classification of true moulds:
Chytridomycota Deuteromycota Oomycota Basidiomycota Zygomycota Ascomycota

30 Chytridomycota Mostly unicellular fungi, occurring in several habitats as soil, roots, rumen of cows Asexual & sexual spores are produced in sporangia and release as zoospores zygote oospore oosphere Meiosis zoosporangium fertilization antherozoid

31 Oomycota Reproduce sexually by oogonia eggs
The mycelium is non septated except under sexual and asexual organs Reproduce asexually by zoospores .

32 Zygomycota Reproduce sexually by zygospore
The mycelium is non septated except under sexual and asexual organs Reproduce asexually by sporangia or conidia Lacking motile spores

33 Ascomycota They have ascospore borne inside ascus
The mycelium is septated Reproduce asexually by conidia

34 Basidiomycota They have basidiospore borne externally on a basidium
The mycelium is septated with a very characterized swelling called clamp connection which have a role in nuclear migration Reproduce asexually by conidia Lacking motile spores


36 Deuteromycota Called fungi imperfecti
Don’t have sexual state in their life cycle The mycelium is septated

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