1. The eukaryotes : Fungi

2. Characteristics of fungi
Eukaryotic
Aerobic or facultatively anaerobic
Chemoheterotrophic
Require low pH, low moisture content
Single cell (yeast) or multicellular
Secrete antibiotics
Cell wall composed of chitin
Cell membrane contain sterol, glucan.
Reproduce by sexual & asexual spores
Some are internal or external parasites; a few are predators that capture prey
Nonmotile
Lack true roots, stems, & leaves
Mycology is the study of fungi

3. Vegetative (non reproductive) Structures of Fungi
Mold and fleshy fungi
Thallus (Body) of a fungus made of tiny filaments or tubes called hyphae
Hyphae contain cytoplasm & nuclei and has a cell wall of chitin
In most molds hyphae contains cross walls called septa with pores to allow the movement of cytoplasm in hyphae. Septa divide them into distinct uninucleated cell like units.
Hyphae with septa are called septate hyphae
Hyphae without septa are called coenocytic hyphae
Hyphae grow rapidly from the tips by cell division

4. Vegetative structure

5. Cross Walls of Hyphae
Coenocytic hyphae where the nucleis of each cell is embedded in the cytoplasm without a cell wall
Eg. Zygomycota, Oomycota
Hyphae with cross walls
Eg. Basidiomycota, Ascomycota

6. The portion of hypha involved in obtaining nutreients is called vegetative hypha and the portion concerned with reproduction is called reproductive hypha/aerial hypha.
Hyphal networks are called mycelium, it is a filamentous mass formed under suitable environmental condition.

7. Yeast like fungi
Nonfilamentous , unicellular fungi
Typically spherical or oval shaped
Facultative anaerobic
Reproduce by budding or fission
Mature buds separated from parent cell to give rise to new cell
Buds fail to detach themselves from parent cell appears as chain like structure called pseudohypha.

8. Dimorphic fungi
Most pathogenic fungi exhibit dimorphism i.e. two forms of growth. Such fungi can grow either a mold like or yeast like format. The mold like forms produce vegetativeand aerial hyphae and yeast like reproduce by budding.
Condition
Temperature dependent at37 they appear as yeast and at 25 they appear mold like appearance.
Also changes with CO2 concentration
On agar surface, Mucor rouxii exhibits yeastlike growth;
in agar it is moldlike

9. Reproductive Structures
Most fungi reproduce asexually & sexually
Asexual reproduction produces genetically identical organisms
 Sexual reproduction in fungi occurs when nutrients or water are scarce
In both case of sexual and asexual reproduction they form spores.
Asexual spores : formed by hyphae , when they germinate produce daughter cell genetically identical to parents.
Sexual spores: produced by fusion of nuclei of two opposite mating type

10. Asexual reproduction involving
Binary fission –exponential growth to increase number
Budding- form small outgrowth that enlarges to increase number
Sexual reproduction involving
Fusion of two opposite mating nuclei.

11. Asexual reproduction
Asexual spores produced by an individual fungus through mitosis and subsequent cell division.
Spores of asexual reproduction:
Sporangiospore
Conidiospore
Chlamydospore

12. Conidiospore : produced in chains
Two types
Arthrospore : formed by fragmentation of separate hypha into single slightly thickened cells.
Eg. Coccidioides immit
Blastoconidia : consists of buds coming from parent cells
Eg. Candida albicans

13. Arthrospore and Blastoconidia

14. Chlamydospore : A thick walled spore formed by rounding and enlargement of hyphal segment.
Eg. Candida albicans

15. Sporangiospore : Formed within a sporangium or sac at the end of aerial hyphae
Eg. Rhizopus

16. Sexual reproduction
Sexual reproduction involve fusion of gametes, gametangia or hyphae. The process may involve only fusion of cytoplasm (plasmogamy) or fusion of nuclei (karyogamy) or production of meiotic spores (meiospores)

17. Plasmogamy
Haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (–)

18. Karyogamy
The + and – nuclei fuse
Meiosis
Diploid nucleus produces haploid nuclei (sexual spores)

19. Classification of Fungi
Fungi are classified by their reproductive structures
The 4 phyla of fungi are Basidiomycota, Zygomycota, Ascomycota, & Deuteromycota

20. Zygomycota sporangium fungi or common molds
Includes molds & blights such as Rhizopus stolonifer (bread mold)
Asexual reproductive structure called sporangium & produces sporangiospores
Sexual spore produced by conjugation when (+) hyphae & (-) fuse is called zygospore

21. Basidiomycota Called club fungi
 Includes mushrooms, toadstools, puffballs, bracket fungi, shelf fungi, stinkhorns, rusts, & smuts
Seldom reproduce asexually, some produce conidiospores.
Basidium is sexual reproductive structure that make basidiospores

22. Ascomycota Called sac fungi
Includes yeast, cup fungi, truffles, powdery mildew, & morels.
Sac Fungi can reproduce both sexually and asexually
Yeast reproduce asexually by budding (form small, bud-like cells that break off & make more yeasts)
Asexual spores called conidia form on the tips of specialized hyphae called condiophores
Ascocarp is specialized hyphae formed by parent fungi during sexual reproduction

23. Deuteromycota Sexual reproduction not yet observed.
Recent suggestion is they are anamorphs i.e. lost their ability to reproduce sexually.

24. Fungus Life Cycle.
Asexual reproduction involves germination of haploid spores, which divide by mitosis to produce hyphae.
Hypha produces specific spores.
Spores are released to continue the cycle.
Sexual reproduction (perfect stage) begins when hyphae of different mating types fuse their cytoplasm in a process called plasmogamy, producing heterokaryotic cells with haploid nuclei.
This is followed by karyogamy, or fusion of nuclei.
The diploid zygote is short-lived and undergoes meiosis, producing haploid spores

25. Fungal Life Cycle

26. Fungal Life Cycle

27. Lichens
Lichens are mutualistic symbiotic organisms. They have a fungus and a algal or cyanobacterial portion.
Mutualistic combination of an alga (or cyanobacterium) & fungus
Alga produces and secretes carbohydrates, fungus provides holdfast

28. Fruticose
Crustose
Foliose

29. Mycorrhizae
Mycorrhizae means “fungus-root”; mutualistic relationship between plant and fungi
The plant photosynthesizes while the fungus more efficiently takes up nutrients and water from the rhizosphere than the roots would alone.
Fungi helps the plants by converting atmospheric nitrogen to ammonia to ensure nitrogen availability

30. Fungal Diseases (mycoses)
• Systemic mycoses Deep within body
• Subcutaneous mycoses Beneath the skin
• Cutaneous mycoses Affect hair, skin, nails
• Superficial mycoses Localized, e.g., hair shafts
• Opportunistic mycoses Caused by normal microbiota
or fungi that are normally
systemic, but can infect any
tissue

31. Importance of fungi Fungal spores cause allergies
Molds, mildew, rusts, & smuts damage crops
Yeasts are used to make beer & bread
 Antibiotic penicillin
Decomposers & recyclers of nutrients
Mushrooms eaten as food
Help form blue cheeses
Aspergillus is used to make soy sauce
Amanita is poisonous mushroom
Can cause yeast infections