Lecture 7- Fucking Mushrooms Flashcards
Examples of fungi and their products
Bread, pizza crust (rising)
Mould on bread
Mushrooms
Beer, wine, spirits (alcohol flavours)
Characteristics of all fungi
- heterotrophs
- main body is haploid
- no sexes
- multicellular (except yeast)
- cell wall made of chitin
- external digestion of food
- no males or females, just have +/- gamete types that are the same size
Structure of of Multicellular fungi
hypha: main body, haploid. basic unit of fungi
mycellcium: branching mass of hyphae
Two kinds of hyphae
One has cell wall divisions. Other one doesn’t. Both have cell walls
1) Septate hyphae
- Have cell wall called septum that separates individual cells
- divide nuclei, have pores that allows nucleus to squeeze through it
2) Coenocytic hypha
- “common cell”
- Doesn’t have septum separating cells
- aseptate
- just nuclei and cytosol
Specialized hyphae
most fungi are saprobes: eat dead matter
Some are adapted to kill animals ex: haustoria
haustoria extend itself into cell walls of other organisms like plants, doesn’t surpass membrane.
-associated with roots in land plants
Growth in fungi
-digest food externally and then grow into it by cell elongation and cell division
General Life Cycle of a Fungi
Most undergo asexual reproduction: mycellium, spore producing structure, spores, germination: hypha grows out of spore
Some undergo sexual reproduction
mycellium, Then two different fungi fuse their cytoplasm called plasmogamy.
After plasmogamy it reaches the HETEROKARYOTIC STAGE: this is where the fungi has two different nuclei in the same cytoplasm that has not yet fused (n+n)
After heterokaryotic stage is karyogamy, when the two individual nuclei fuse together to form a diploid zygote
Zygote then undergoes zygotic meiosis producing haploid spores. Zygote just undergoes meiosis, (doesn’t go off to become some diploid structure)
The spore then germinates: hypha body grows out of it
Then enters asexual life cycle
Fungi Spores
-Resistant, last a long time
-single haploid cells (n)
-very small, less than 20 um
-Each contain a nucleus, dehydrated cytoplasm, and protective coat
-Some remain dormant for a long time
Produced by
Asexual reproduction : mitosis
Sexual reproduction: zygotic meiosis
Function of spores
Main way how fungi get around:
- Move to a new food source
- avoid or “wait out” bad environment
- sexual reproduction
3 types of Asexual reproduction in Fungi
Asexual reproduction can occur in 3 ways:
1) Spores in sporangia: created by the fungal body making spores at tip of hypha
2) Conidia (spores) in Conidiophores: Spores/conidia born on extensions called condiophores. ex: penicillin
3) Budding: only happens in single celled fungi: yeasts
- parent cell buds of daughter cell, has a scar at that point and cannot produce another daughter cell at that point
Fungi are closely related to
animals
There are ….. phyla of fungi
1) Chytridmycota
2) Zygomycota
3) Glomeromycota
4) Ascomycota
5) Basidiomycota
Phylum Chytridmycota
- 1,000 species
- single cells or colonies with hyphae
- single cell has flagellated “zoospore”: haploid and “zoo: because it swims
- Aquatic or soil environment
- Mutualistic decomposers/parasites commensals (benefits itself but doesn’t affect others)
Spore release in a chytrid
- converted entire contents of its thallus: flasked-shaped body into flagellated asexual zoospores
- Single cell, made a whole bunch of mitotic divisions of its nucleus
- puts a cell wall around each and releases them all to environment
Chytrids are parasites
Responsible for 1/3 amphibian decline
-infects skin
Phylym Zygomycota
-1,000 species
-Coenocytic (nonseptate) hyphae
-Decomposes, parasites, commensals
-zygosporangium
ex black bread mould
-produce asexual spores
Zygomycota life cycle
1) Mycelium comes out of spore and sends up a stalk. At end of each stalk is sporangium
2) Sporangium produces ASEXUAL spores
3) Occasionally undergoes sexual reproduction, when it does, 2 different fungi fuse cytoplasm through plasmogamy.
4) Plasmogamy produces zygosporangium
5) 2 nuclei fuse in karyogamy (have +/- gamete types) forming diploid nuclei.
6) Diploid nuclei immediately undergo meiosis producing sporangium and spores
Phylum glomeromycota
- 160 species
- associated with plant roots that are mutually beneficial, can’t live without them
- non-septate
- called arbuscular mycorrhizae: when they enter plant root, they form a branching structure that is shrub like.
- doesnt break membrane, helps plant cell pick up phosphorous
- in 90% land plants roots
Phylum Ascomycota
- “sac” fungi
- 65,000 species
- Unicellular (yeast)
- Multicellular (truffles, cup fungi, morels)
- produces acrospores
- blue cheese (blue spores) and penicillin (asexually reproduced spores)
mycorrhizae
association with roots
Truffles
- associated with oak roots
- found underground
- ectomycorrhizae
Asexual reproduction in ascomycota
unicellular asexual reproduction: budding (yeast)
multicellular asexual reproduction: formation of conidia (spores) on conidiophores
Sexual reproduction in ascomycota
makes 8 haploid spores in each ascocarp: “fruiting body”
produces spores called ascospores
fruiting body looks like cup
Life cycle of ascomycota
- Asexual reproduction by condo
- spores created at ends of mycelium, clones of parent
- If organism undergoes sexual reproduction: 2 mating types fuse cytoplasm in plasmogamy creating a DIKARYOTIC HYPHAE. 2 nuclei fuse in karyogamy producing diploid nucleus
- Diploid nucleus undergoes meiosis producing 4 haploid cells
- 4 haploid cells undergo mitosis to produce 8 acrospores in the fruiting body
Ex of ascomycota: ergot alkaloids
- claviceps purpurea
- several kinds
- turns rye seed/flour into container of spores
- restrict blood flow: gangrenous ergotism
- St.anthonys fire: feel like u are on fire
- Causes hallucinations, believed to cause salem witch trials
- Medical uses
- led to discovery of LSD
other examples of ascomycota
boytris: creates crop destructruction, strawberries and wine
Budding/Brewer’s/Baker’s yeast
used to raise bread, used in spirits and wine
Candida albicans
- normal part of human gut, skin and oral cavity, genital tract
- transmitted from mother to child in birth
- pathogenic
- 2 morphological forms: yeast and hyphae
Phylum Basidiomycota
-30,000 species, second biggest division
-fruiting body is basidiocarp (where sexual reproduction occurs)
-mushrooms and puffballs
-decomposes forests and ectomycorrihizal: on the outside of roots
-long lived dikaryotic mycelium (mycelium with two individual nuclei floating around)
-club fungi
ex shittake, amanita
basidium = pedestal
Life cycle of a basidiomycete
1) plasmogamy with plus and minus mating type
2) Produces dikaryotic mycelium that reproduces sexually: undergoes karyogamy
3) Diploid nuclei undergo meiosis
ALL HAPPENS IN THE GILLS OF THE MUSHROOM
4) produces 4 products called basidiospore, released from gills
Distinguishing features of morphology and life cycles
Chytridiomycota: flagellated zoospores
Zygomycota: resistant zygosporangium as asexual stage
Glomeromycota: form arbuscular mycorrhizae with plants
Ascomycota: Sexual spores (Acrospores) borne internally in sacs called asci, produces a lot of asexual spores (conidia)
Basidiomycota: fruiting body/basidiocarp containing many basidia that produce sexual spores (basidiospores)
