Mycology

Question 1

why are fungi heterotrophs

Answer 1

they cannot create their own nutrients must be absorbed

Question 2

what is the cell wall of fungi made from

Answer 2

chitin

Question 3

what are the three main components in the general structure of fungi

Answer 3

hyphae, mycelium, spores

Question 4

what are hyphae

Answer 4

filamentous structures that branch repeatedly into a complicated, radically expanding network called the mycelium. In most fungi are the main mode of vegetative growth

Question 5

what is the mycelium

Answer 5

the mass of interwoven hyphae that forms the vegetative portion of the thallus of a fungus. Is often submerges into another body (soil or organic matter of the host)

Question 6

what are spores

Answer 6

reproductive structures produced by fruiting bodies. Microscopic biological particles that allow fungi to be reproduced. (similar to seeds). Usually asexual (can be sexual). Produced in high numbers. Released actively or passively from the basidia or asci or from the fruiting body respectively

Question 7

what is a coenocyte

Answer 7

a multinucleate cell which can result from multiple nuclear divisions without their accompanying cytokinesis

Question 8

what is plasmogamy

Answer 8

a stage in the sexual reproduction of fungi, in which the protoplasm of two parent cells fuse without the fusion of nuclei

Question 9

what are dikaryons

Answer 9

cells in which two nuclei, one from each parent cell, share a single cytoplasm for a period of time without undergoing nuclear fusion.

Question 10

what are the two main types of hyphae

Answer 10

septate hyphae and coenocytic hyphae

Question 11

how do you determine the species of a fungi

Answer 11

shape, size, colour, context of the spores

Question 12

spores can be produced sexually and asexually depending on what

Answer 12

environmental conditions and reproductive identity

Question 13

why do fungi have high odds of finding a mate

Answer 13

because there are up to a thousand sexes wherein any type can mate with any other type as long as it is NOT itself

Question 14

what are the asexual reproductive stages of fungi

Answer 14

Mycelium (n)
Spore producing structures (n)
Spores (n)
Germination

Question 15

what are the stages of sexual reproduction in fungi

Answer 15

Mycelium (n)
Plasmogamy (fusion of cytoplasm)
Dikaryotic stage (n + n)
Karyogamy (fusion of nuclei)
Diploid stage (2n)
Spore producing structures (n)
Spores (n)
Germination

Question 16

Fungi are more related to ______ than they are ______

Answer 16

Fungi are more related to animals than they are to plants

Question 17

what are Zygomycota

Answer 17

a phylum of the fungi kingdom, Hyphae are coenocytic except in reproductive structures. Produce zygospores from sexual reproduction, and Sporangiospores from asexual reproduction. Produce bubbles where spores are contained (moudly bread)

Question 18

what are Ascomycota

Answer 18

the largest phylum of the fungi kingdom, grouped together with Basidomycota forms Dikarya subkingdom. aka Sac fungi because they contain 8 ascospores in sac-like structures called asci (ascus). goes through 3 mitotic divisions and has septate hyphae.

Question 19

what are Basidomycota

Answer 19

a phylum of the fungi kingdom. ‘club fungi’ because 4 basidiospores sit on a club like structure called a basidium. have septate hyphae. can smell like rotting meat.

Question 20

what are the environmental roles of fungi

Answer 20

decomposers, symbionts, pathogens/parasites,

Question 21

what are the benefits of fungi decomposing litter

Answer 21

• Nutrients absorbed from decaying material
• Nutrients made available to other organisms
• Nutrient recycling – without fungi wouldn’t happen so greatly
• No fungi, no decaying of wood

Question 22

what is Mycorrhiza (benefits?)

Answer 22

symbiotic association between fungus and roots of a vascular plant.

• Fungus benefits: access to carbohydrates
• Plant benefits: access to mineral nutrients

Question 23

what is Ectomycorrhiza

Answer 23

extracellular symbiotic association of fungi with the feeder roots of higher plants in which both the partners are mutually benefited - fungus hyphae grow between plant root cells and rely on carbs leaking from them

Question 24

what is Endomycorrhiza

Answer 24

Intracellular fungi symbiosis with plants in which the hyphae haustorium penetrate the plant root

Question 25

what are lichens

Answer 25

a complex life form made of a symbiotic partnership of fungi and algae/bacteria. algae/bacteria provide the nutrients and fungi provide a structured stable environment

Question 26

how do ants/termites have a mutualistic symbiotic relationship with fungi

Answer 26

ants and termites cultivate fungi into their gardens (farming :) - ants/termites propagate nurture and protect the fungi and the fungi act as a food source for the ants

Question 27

give three examples of obligate fungi

Answer 27

``` o Rust fungus (Pucciniales) – plants o White nose syndrome (Pseudogymnoascus destructans) – bats o Chytridiomycosis (Batrachochytrium dendrobatidis) – amphibians ```

Question 28

what are entomopathogenic fungi

Answer 28

- a fungus that can act as a parasite of insects and kills or seriously disables them

Question 29

how do fungi cause death of some insects

Answer 29

the fungus produces aerial spores that land on the exterior of the insect, spores germinate and penetrate into the insect cuticle and fungus grows throughout the body. blastospores and mycelium growth kill the insect in 4-14 days then transforms into mycelium on hosts death

Question 30

what are the benefits of fungi to humans

Answer 30

``` direct food source (mushrooms) indirect food source (wine, beer, bread etc) recreation biopesticides crop yield boosting (inoculation and symbiosis) mycoremediation (decontamination) enzyme production medicines research ```

Question 31

what is the growth form of yeast

Answer 31

asexual growth through budding (single-celled and has no hyphae)

Question 32

what are the two pathways that Saccharomyces spp produces ATP from sugars

Answer 32

1. Respiration delivers more energy (28vs 2 ATPs) but requires oxygen 2. Fermentation results in ethanol and CO2: respiration only CO2 Use of CO2: rising of bread dough Use of ethanol: alcoholic drinks

Question 33

what is the active ingredient in magic mushrooms and how does it provide its effects

Answer 33

Psilocybin or Psilocin (basidiomycota species) - structural similarity with serotonin interfering with the receptors in the brain

Question 34

mycoremediation can be used to decontaminate what

Answer 34

Heavy metals: Pleurotes (‘B’), Aspergillus (‘A’), Trichoderma (‘A’) Organic pollutants: (PAHs, petroleum, PCBs etc) wood decay fungi, Pleurotes (‘B’), Pestalopiosis (‘A’) Pesticides, dyes, etc

Question 35

give two examples of entomopathogenic fungi used as biopesticides

Answer 35

Beauveria bassiana (‘A’) and Metarhizium anisopliae (‘A’)

Question 36

what enzymes are produced using fungi and using which fungi

Answer 36

Proteases, cellulases, xylanases, lipases, amylases, phytases, etc Aspergillus (‘A’), Penicillium (‘A’), Rhizopus (‘Z’), Trichoderma (‘A’), etc

Question 37

what medicines are produced by fungi

Answer 37

Antibiotics: penicillin and others Statins: Penicillium spp (‘A’), Aspergillus terreus (‘A’), Monascus purpureus (‘A’), etc Anti-cancer drugs: Penicillium spp (‘A’) Anti-fungal drugs: Penicillium spp (‘A’) Immuno-suppressant drugs: Penicillium spp (‘A’), Tolypocladium inflatum (‘A’), etc Drugs against malaria, diabetes Production of D vitamins

Question 38

how can fungi be used in research and what is the most studied one

Answer 38

Saccharomyces cerevisiae (‘A’) - Model organism in cell biology, genetics, DNA repair, aging

Question 39

what threats do fungi pose to humans

Answer 39

poisonous mushrooms toxic moulds moulds on foods

Question 40

what are amanita and how are they poisonous

Answer 40

a genus of fungi, some of the most toxic mushrooms in the world (Amanita phalloides -death cap) and some edible. produce amatoxins that are inhibitors of RNA polymerase 2: so cell metabolism is halted and cell lysis occurs

Question 41

what is the biphasic clinical pattern of amanita ingestion and poison

Answer 41

* Initial period of acute symptoms: headache, dizziness, nausea, shortness of breath, coughing, insomnia, diarrhoea, gastrointestinal disturbances, back pain, frequent urination. * 12-24 hour recovery * after recovery, 2nd phase… Death through multiple organ failure

Question 42

what species causes the toxic mould ergot

Answer 42

Claviceps purpurea and related species (‘A’)

Question 43

what is the treatment for ergot poisoning

Answer 43

Treatment: sodium nitroprusside or nitroglycerine

Question 44

what are the symptoms of ergot poisoning - what systems does it infect

Answer 44

Alkaloids affect the a) nervous system and b) vascular system a) muscle spasms, fever, hallucinations, nausea, seizures, vomiting, unconsciousness, death b) violent burning, peripheral pulses, shooting pains in fingers and toes, gangrene, loss of limbs (‘St Anthony’s Fire’)

Question 45

what are rusts and smuts caused by and how do they effect the plant

Answer 45

caused by pathogenic fungi in Basidiomycetes class. cause rusts and smuts to appear on plant and a severe drop in yeild

Question 46

what are the treatments for rusts and smuts

Answer 46

fungicides and breeding from resistant genotypes

Question 47

what fungi causes dutch elm disease, how is it transmitted?

Answer 47

Ophiostoma ulmi (‘A’) - Vector is bark beetle carrying fungal sprore – they get into bark and create corridor system which they use to breathe.

Question 48

what are the treatments for Ophiostoma ulmi (‘A’) infection of dutch elms

Answer 48

 Destroy diseased trees.  Target bark beetles  ‘Vaccinate’ trees with weaker fungus strain  Breed from resistant genotypes

Question 49

give three examples of major fungal tree pathogens

Answer 49

Ash dieback - Hymenoscyphus fraxineus (‘A’) Honey fungus - Armillaria spp (‘B’) Dutch elm disease – Ophiostoma ulmi (‘A’)

Question 50

why could wood decaying fungi negatively impact humans

Answer 50

if a structure is made of wood, fungi will break down the cellulose and lignin in the wood and cause it to crumble so the whole thing collapses - dry rot causes >£150million annually

Question 51

what are the treatments for dry rot

Answer 51

* Environmental (lower humidity, increase ventilation) * Fungicides * Heat * Biological control (competing fungus species)

Question 52

give 4 examples of fungal pathogens that infect humans can what they cause

Answer 52

Candidiasis: Candida albicans and other spp (‘A’) - cause thrush Dermatophytosis: Trichophyton, Microsporum, Epidemophyton (‘A’) - cause athlete foot, ring worm, fungal nail Aspergillus: Aspergillus spp (‘A’), (forms aspetgiloma in lung 'fungal ball') Cryptococcus: Cryptococcus spp (‘B’) - cause meningitis & meningoencephalitis

Question 53

what are microsporidia

Answer 53

a eukaryotic phylum of single-celled organisms (approx 1500 species)(small genome) they are spore-forming obligate intracellular parasites (evolutionary loss of genes)

Question 54

what is a meront

Answer 54

part of the microsporidia lifecycle inside human host cells

Question 55

what is the structure of meronts

Answer 55

– Membrane often has vesicles and tubules that serve to increase surface area of contact with the host cell so it can steal more nutrient. – One (monokaryon) or two (diplokaryon) nuclei. – Lots of ribosomes. – No mitochondria (v odd) (have mitosomes)

Question 56

what is the key characterisitc of microsporidium spores

Answer 56

Rows of mysterious circles/ovals are cross-sections of coiled-up polar filament/tube -Only microsporidium spores have this polar filament no other on earth

Question 57

how do you distinguish between microsporidium species

Answer 57

the pattern of polar filament coils in their spores is often species specific (Indicative spore organisation, the polar filament can be different sizes and orientations inside the spore)

Question 58

how do microsporidium infect the the host cell

Answer 58

spores contain an extrusion apparatus that has a coiled polar tube ending in an anchoring disc at the apical part of the spore - enables spore contents and nucleus to be injected into the host cell

Question 59

how are microsporidia classified

Answer 59

related to fungi (highly specialised fungi, losing many traits to parasitic lifecycle very primitive eukaryotes - before endosymbiosis event (ssuRNA and other molecular data)

Question 60

what is the lifecycle of microsporidia

Answer 60

1. Environmental cues tigger germination (eg osmotic pressure) 2. Polar filament pierces membrane of host cell 3. Spore content (sporoplasm or polarplasm) is injected into host cell 4. Meront start dividing in the host cell

Question 61

how does the spore polar filament gain the energy for expulsion

Answer 61

tension of coil, as soon as trigger occurs it is shoots out, a flexible hypodermic needle crossed with a harpoon.

Question 62

what 3 phases does the microsporidia go through

Answer 62

infective/environmental phase (spore)(extracellular) -> proliferative phase (meront) -> sporogonic phase (sporont)

Question 63

what is the host range of microsporidia

Answer 63

As a group, microsporidia infect a wide range of organisms from ciliates, ‘worms’, arthropods, fish and mammals (Especially arthropods) Not known from plants (mixture of lifecycles)

Question 64

describe some aspects of pathogenicity of microsporidia

Answer 64

* Can infect a wide range of tissues (guts, liver, kidney, brain, muscles, eyes, etc) * Sometimes cyst-forming (especially in fish) * Increased mortality * Can influence sex determination (arthropods), through female, female infected, help microsporidium spreads. (change host from male to female beneficial for parasites) * dependent on state of individual - often more severe in weakened individuals (vertebrates) * Transmission often via environmental spores

Question 65

what happens when microsporidia infect drosophila larvae

Answer 65

If larvae are infected the adult is infected. When the adults die they can infect larvae again (body ) if parasitoid attacks infected larvae, then parasitoid will be infected. No transmission from parasitoid in drosophila. Dead end from microsporidium when they infect parasitoid

Question 66

what does microsporidia do in humans

Answer 66

– Can cause intestinal, lung, kidney, brain, sinus, muscle, or eye disease – often chronic (mostly opportunistic infections in immune-compromised individuals)