lecture on fungi [11 25-13 monday]
TRANSCRIPT
Characteristics
• nonphotosynthetic• Most are saprobes (feed on dead things)• Cell wall made of chitin• Genetically more similar to animals
Importance
• Decomposer and recycler of nutrients• Consumed as food and food production• Truffles, morels, mushroom • Antibiotic: penicillin
Antibiotics
• Cyclosporin prevent organ rejection• Statin lowers cholesterol• Penicillin
Mutual symbionts of pants
• Mycorrhizae• lichens
Three forms of lichen (Know for lab exam)
1. Crustose: crustlike, growing tight against the substrate.
2. Foliose: leaflike, with flat sheets of tissue not tightly bound
3. Fruticose: free-standing branching tubes.
Four Fungal diseases
1. Thrush: yeast infection2. Histoplasmosis : lung infection3. Aspergillosis : mold in your house4. Cryptococcus /Valley fever: can lead to
pneumonia and meningitis
ergotism
• Clavicles fungus• Salem witch trials
Sporotrichosis: rose gardener’s disease
• Fungal antibiotics are harmful; humans and fungi are eukaryotes. Bacterial infections are better to treat because they are prokaryotes
Tinea Infections (Ringworm)
• Infection on skin and nail’s keratin
Claviceps purpurea, cause of ergotism
Plant diseases caused by fungi
1. Rust2. Apple Scab 3. smut
cellular
• Unicellular (yeast)• Multicellular (mold)
• Some are yeast inside and mold outside the body
Structure
• Mycelia: networks of branched hyphae (cells)• Septum (cell wall) separating the hyphae• Coenocyte fungi lack septa and cellular
contents can flow between the hyphae
Septate hyphae
• Septum: a cross-wall formed in association with the mitotic division of a cell, laid down between the cells, usually at regular intervals.
Coenocytic hyphae
• multinucleate mass of protoplasm resulting from repeated nuclear division unaccompanied by cell fission
Types of mycorrhizae fungi
• Ecto : grow into the extracellular species of the root cortex (truffle)
• Endo: grow into the root cell (orchid)
Reproduction
• Plasmogamy: union of two parent mycelia• Heterokaryon: cell or mycelium in some fungi
that do not result in the fusion of two nuclei• Dikaryotic: the nucleus pair off two to a cell
Karyogamy (nuclear fusion)
• Produce diploid cells• Takes a long time• 2n phase is short-lived and undergo meiosis,
producing 1n spores
sporangium
• Fungal structures where asexual spores are produced
• exam
Groups you must know
1. Chytridiomycota: earliest fungi2. Zygomycota3. Glomeromycota4. Ascomycota5. Basidiomycota
Chytridiomycota: earliest fungi
• Found in water• Saprobic or parasitic• B. dendrobatids: decline of frog population• Chytrids diverged earliest
Zygomycota
• Asexual and sexual spores• Zagospore (sexual)• Sponragiospores (asexual spores) • Very cold/heat tolerant, responsible for food
spoilage• Black bread mold Rhizopustoloniser• pilobolus
glomeromycota
• Arbuscular mycorrhizae: endo• 80% of all vascular plants have arbuscular
mycorrhize• Reproduce asexually• Help plants absorb phosphorous and help a
crucial role in colonization of land by plants
Ascomycetes (cup fungi)
• Asci: sexual spores that are found in saclike structure
• Reproduce sexually• Many asci are found on the fruiting body
called ascocarp• Ex. Truffle• Conodia: asexual spores• Conodiophore: structure
Penicillium conidiophores
Basidiomycetes: typical mushroom
• Basidium: structure where sexual spores (basidiospores) are produced
• Gills with basidia
Reproduction of Basidiomycetes: typical mushroom
• Sexual mostly resulting in dikaryotic fruiting bodies called basidiocarps (mushroom)
• Karygomy occurs in the gills of the mushroom cap where basidium and basidiophores are found
• Asexual reproduction is rare and occur via fragmentation
• Ex. Club fungi, rust, smut, puff balls, shelf fungi, mushrooms
Basidiomycete life cycle• Basidiomycetes – Fungi• Key Points• The basidiomycetes (phylum Basidiomycota) are comprised of roughly
30,000 species that include mushrooms, shelf fungi and puffballs.• The basidium is a specific, club-shaped cell where karyogmay is carried
out followed by meiosis. This gives rise to the name club fungus.• A diploid nucleus is formed during karyogamy and then undergoes
meiosis, resulting in four haploid nuclei. The basidium divides into four arms, with a single haploid nucleus in each that will develop into a basidiospore.
• The reproductive cycle of basidiomycetes has a long dikaryotic mycelium stage allowing for genetic diversity as a result of recombination.
• Basidiomycetes are particularly important in nature as decomposers of plant material, especially dead wood and trees.
• Terms• basidium
a small structure, shaped like a club, found in the Basidiomycota phylum of fungi, that bears four spores at the tips of small projections
• Karyogamy The fusion of two nuclei within a cell.
• Mycelium The vegetative part of any fungus, consisting of a mass of branching, threadlike hyphae, often underground.
• mycelium the vegetative part of any fungus, consisting of a mass of branching, threadlike hyphae, often underground
Glossary
• http://bugs.bio.usyd.edu.au/learning/resources/Mycology/Glossary/glossary_a_b.shtml