Fungi Flashcards

Question

Spread-going with wind

Answer 1

Ex. Ascomycetes 1. Plasmogamy: Mycelia—>**ascogonium and antheridium fuse** 2. Mitosis and cell division: formation of many dikaryotic hyphae, form a fruit body called **ascocarp**, **ascus(asci)** form at the tips of hyphae 3. Karyogamy: Nuclei in the asci fuse to form a **diploid zygote** (2n) 4. Meiosis: an ascus with 4 haploid nuclei is formed 5. Mitosis and cell division: **8 haploid ascospores** are formed 6. Dispersal and germination Asexual cycle: mycelia—>mitosis: spores—>germination—>mycelia

Answer 2

1.Apothecium Shotgun Cup fungi 2.Perithecium Rifle Flask fungi 3.Cleistothecium Grenade Release all at the same time

Answer 3

Ex. Pilobulus sp.(zygomycetous fungi) Sexual reproduction: 1.spores germinate to 2 mating types, when grow close enough, extension of mycelia (1n) called **gametangia** form between them 2.Plasmogamy: fusion between +/- mating types result in a **zygosporangium(form a thick protective coat)** with multiple haploid nuclei 3.Karyogamy: Nuclei fuse to form a **zygote(2n)** with **multiple nuclei** 4.Meiosis and Germination: a **sporangium(1n, haploid spores form inside)** grows on a short stalk 5.Germination Asexual reproduction: spores—>mitosis—>mycelia—>germination

Answer 4

Might wipe out a entire species from earth

Answer 5

Fungi might contribute to the extinction of the dinosaurs since they cannot grow under 37 degree, mammal survival

Answer 6

Bd & Bsal: Chytrids belongs to zoosporic fungi Amphibians are killed by disrupting the skin functions, leading to cardiac arrest Animal trade disseminated(传播) the chytrids on all continents. Close to 100 species already extinct. 2nd most dangerous species for biodiversity

Answer 7

Blue stain fungus carried by a beetle Beetles make holes on pine trees and infect the fungi in the tree. 3 main species of blue stain fungus affect pine trees: (Ascomycota - Sardoriomycetes) -Grosmannia clavigera -Ophiostoma montium -Leptographium longiclavatum Fungi colonize the tree phloem and feed on the sap, leading to pine tree death In Montreal Rhytima sp. • 60,000 trees replanted (Norway maples: faster growing with yellow leaves) • Norway maples are very susceptible to tar spot. • Native sugar maples are relatively resistant

Answer 8

Pathogen: Pseudogymnoascus destructans (Ascomycota) -Saprotroph -Loves cold temperatures Mortality: 5 million/year 70–100% of bats infected will die because of metabolism shutdown As temperatures rise, immune system controls the infection, 但是下次冬眠会感染更多，一直循环消耗，直到bats在冬眠结束前死亡

Answer 9

In Europe: No mass mortality A **mycovirus** uniquely found in North American Pd isolates. Viruses infect fungi: RNA in fungi encodes virus enzymes: -Some increase the virulence e.g., Pd -Some decrease the virulence e.g., Aspergillus fumigatus a human pathogen), it let fungi survive longer. In the early 2000s, Europeans brought Pd & mycovirus to caves in New York State.

Answer 10

1. **Pollination** More than 300 fruit trees depend on bats for pollination 2. **Insect population control** (bats feed on insects): -Saves money spent removing bugs ($4 billion/year) -Reduces the abuse of insecticides.

Answer 11

Herbs -Half of the banana is difficult to obtain through fertilization (seed is too big) -Selected those that don’t require fertilization and spread them everywhere

Answer 12

Tasty conquered the world **Fusarium oxysporum TR1** Ascomycota – Sardoriomycete 1874 - Australia: Banana farm decimated大量毁灭 by fungal disease Fusarium: -lives in the soil -their spores sense plant growth (via materials secreted by roots) -Spores germinate, invade plant roots, grow in **xylem**, and lead to the plant lose their water supply, fungi will clog the vessels and this cause plant death -fungi sexual/asexual reproduction -spore left in soil

Answer 13

Less tasty, less long-lasting History repeats with **Fusarium oxysporum TR4**

Answer 14

1. The only solution is to use anti-fungal, but: Antifungals create resistance, and we use antifungals to treat ourselves 2. Gene editing is not a complete solution (other strains might infect in the future+Global trade)

Answer 15

Pathogen: Puccinia graminis Basidiomycota -In the summer, P. graminis reproduces asexually in wheat, growing fast and spreading spores via wind -In winter, they switch hosts to barberry plants and reproduce sexually -when temperature rise, switch back to wheat Farmers’ Response -Removed barberry plants → Wheat rust disappeared for nearly 60 years -Later, to protect barberry carpet (moths), black barberry plants were restored → Wheat rust returned

Answer 16

Symbiotic relationship between plants and fungi. Present for 450 million years and found in 80% of plants. Fungi: mainly Glomeromycotina (Zygomycetes)

Answer 17

1. Arbuscular. 2. Ectomycorrhizae 3. Orchid → seeds can't germinate without fungi 4. Ericoid

Answer 18

With mycorrhizal fungi, roots can cover more soil to get nutrients.

Answer 19

1. Arbuscular Mycorrhizae Fungi (AMF) 2. Ectomycorrhizae

Answer 20

1. Zone of exchange between plants and fungi -Fungi improve water and nutrient assimilation (e.g., N, P…) Ex. Plants can't take phosphate on their own, they need fungi to take it for them -Plants provide carbon (carbohydrates, lipids) to fungi 2. Improved soil quality -Fungi secrete **glomalin** (hydrophobic glycoprotein), which interact with particles in soil and start to organize it in macroaggregate Fungi can improve: -Soil structure -Carbon sequestration. -Water flow and availability -Biodiversity -Heavy metal absorption A richer soil can support more life 3. Stimulate plant immune defense -sometimes plant consider fungi as a "pathogen attack," triggering immune responses -Benefits: 1. Pathogen presence prevention 2. Stimulation of the plant general health/metabolic activity (defense)—**ISR (induced systemic resistance)** Harnessing利用 mycorrhizal fungi enables more sustainable agriculture

Answer 21

gray mold Ascomycota, leotiomycets Bad Side -Causes ~$10 billion/year crop losses. Good Side -"Noble Rot" → Sauternes -Ideal growth conditions in France plant farm: Cool, moist in the morning; warm in the afternoon

Answer 22

1. Semillon → main grapes used with thin skin grapes 2. Sauvignon Blanc → bring acidity to the wine 3. Muscadelle → Grapes with floral note easily infected by fungi

Answer 23

1. Fungi land on the top of grapes and grow germ tubes (**Appressorium**) destroy the first layer of cells in epidermis 2. Hyphae grow, penetrates the grape, starting infection 3. Grape skin bursts as fungi grow, creating holes, water evaporates, give a sweet flavor 4. Hand pick harvest of the grape with noble rot with correct maturation degree

Answer 24

Penicillium roqueforti (Ascomycota - Eurotiomycetes) Recent fungi with long tubes septated Proteolysis of dairy protein and lipids, secretion of flavorful secondary metabolites

Answer 25

Blue comes from the spores of the fungi Spore is made through asexual reproduction To make better cheese: force penicillin do sexual reproduction to recombine DNA

Answer 26

Fungi: Amanita phalloide (Basidiomycota) -Produces **amatoxins**: cyclopeptide toxins, which is heat stable and unaffected by drying -Lethal dose: 0.1 mg/kg (up to 15 mg/ a mushroom cap) -Inhibits RNA polymerase II -Responsible for most mushroom poisoning deaths

Answer 27

Fungi: Psilocybin & Psilocin -Alters the way of the perceive of reality -Used in ancient civilizations (e.g., Aztecs). "Stone Age Theory": Brain size increases linked to mushroom use. Highly criticized Psilocybin agonist at cortical serotonin 5-HT2A receptor, they are used in clinical for depression and PTSD

Answer 28

Claviceps purpurea - Ascomycota, Sordariomycete -Host: rye -Reaction: lysergic acid(psychoactive drug) +diethylamine=LSD Injection with Rye with fungal infection—> the witches trial in middle age

Answer 29

Ascomycota - Sordoriomycete -Scheele's green + growth of S. brevicaulis → releases As (arsenic) to the air -product of this reaction is trimethylarsine which cause Gosio’s disease

Answer 30

Many fungi secondary metabolites exploited for commercial and medical applications, only a minority remain major health or economic concerns (ex. Aflatoxin) Tomes fomentarius: Burnt on joints to treat arthritis (药膏). Echionodontium tinctorium: Mixed with grease to make sunscreen. Haploporus odorus: Smoke used to relieve headaches. Bovista pila: Spore used to prevent/stop nosebleeds. Amanita muscaria: Concoction used to make eye-drop solutions.

Answer 31

80% of the population will be affected once across their life by fungi. Some infections cause severe diseases.

Answer 32

Most common infection and often benign Frequent in immunocompetent 正常免疫者 Provoked by dermatophytes (Tinea) 皮肤真菌, feed on keratin

Answer 33

Rare but fatal if untreated. Mostly in immunocompromising patients (免疫障碍病人). Example: Mucormycosis (严重致命性菌病)

Answer 34

ring worm easy to treat, only need topical antifungal therapy

Answer 35

-5-10% population -Difficult to eradicate (难以根除) -3-6 months oral antifungal -Also called onychomycosis (甲真菌病)

Answer 36

Commonest fungal infection of humans Up to 70% of all Tinea Topical antifungal therapy for 10-14 days Recurrence common Feed on skin

Answer 37

Superficial infection 3 different forms Yeast form → pseudohyphae → true hyphae (causes disease) Commensal with humans (GI tract, mouth, vaginal flora) Morphological switch is required for virulence (not completely understood) Examples of disease: Oral thrush, diaper dermatitis, vaginal candidiasis, balanitis

Answer 38

1. Yeasts -Systematic disease, pulmonary disease, absent or subclinical -Have little or no clinical symptoms. 2. Molds -Primary pulmonary disease with dissemination (传播) -rarely spreads to the whole body 3. Dimorphic fungi -Primary pulmonary disease with dissemination as the prominent part of disease -Can convert to hyphae forme, spread in the body

Answer 39

Yeast Invasive infection -从缺口go into blood, and go to different organs -Affects immunocompromised patients. -Fatal if untreated; even if treated, mortality is 20–50% -Average stay at hospital: 2–8 weeks.

Answer 40

Yeast Invasive infection Basidiomycota **Encapsulated** an rigid & dense outer layer of sugar protects cell wall, a massive virulence factor

Answer 41

C. neoformans & C. gattii. Living environment: soil Eucalyptus trees bird droppings

Answer 42

Acquired by breathing yeast or spores **Pulmonary infections** -often misdiagnosed as cancer -Asymptomatic in 25-50% of cases. -Patients with diagnosis need to do a CSF puncture because Cryptococcus loves to go into your brain and cause cryptococcal meningitis (macrophage engulfs yeast; macrophage goes through the BBB; yeast can be released into the brain) HIV+ patients: 80% CSF culture are positive for Cryptococcus Treatment: 3 phases: -Induction: 1 week under amphotericin B -Consolidation: high dose of fluconazole -Maintenance: low dose of fluconazole for a year Example: Cryptococcus gattii (appeared in1999) -homothallic reproduction -cause pneumonia, and meningitis in immunocompetent patients -infecting native trees and soil

Answer 43

Infection in lungs, rarely disseminating. Majority are opportunistic, very aggressive, and destructive. Aspergillus most common (>80%): -Aspergillus fumigatus most common species (Ascomycota) -Cause invasive pulmonary aspergillosis Other species: -Zygomycetes: Rhizopus, Absidia, Mucor -Penicillium -Pseudallescheria boydii

Answer 44

Conidiophores → **Conidia** (asexual spores) Healthy individuals: eliminated by the innate immune system and the mucociliary elevator. For immunocompromised patients: pathogen goes to alveolar and then blood vessel → lung Cause: 1. Invasive Pulmonary Aspergillosis 2. Chronic Aspergillosis: If you have impaired lung function, stays at the impaired place and grows.

Answer 45

Endemic mycoses: 地方性真菌病 Infection type switch in the middle Infect immunocompetent individuals Geographically restricted in range Environmental mycelium form vs. infecting yeast form

Answer 46

Dimorphic fungi infection Environment (25°C): -saprophytic mycelium forming microconidia found in wood; a major dog pathogen -Endemic region: Great Lakes and Mississippi Valley. Human body (37°C): -**parasitic yeast** -Lung infection → dissemination to blood and other organs -Cutaneous 皮肤的 secondary infections are frequent —>grow into mold Low Mortality

Answer 47

limited because we are both eukaryotes, maybe toxic to us

Answer 48

1. Cytoplasmic membrane → ergosterol 2. Cell wall

Answer 49

β-1,3-glucan Chitin: Will also affect insects and shellfish **Echinocandins**: cell wall inhibitors -Newest family of molecules approved by the FDA (2001) -Fungicidal to yeast: kill -Fungistatic to mold: stop growth Example: caspofungin

Answer 50

Ergosterol: ensures fungal plasma membrane fluidity Two families of antifungal drugs targeting ergosterol: -Polyenes -Azoles

Answer 51

1950s Ergosterol binder Makes holes in the membrane. Only used in severe cases of invasive infection Important toxicity: Maximum dose: 1 mg/kg/day over 2-4 hours. Cholesterol & ergosterol (structural similarity) Example: Amphotericin B

Answer 52

1960s Inhibitor of ergosterol synthesis 2 types of structures: -Contain **imidazole** group (2 N) -Contain **triazole** group (3 N) Fungicidal: mold infection (invasive) Fungistatic: yeast

Answer 53

For all drugs, the resistance relate is increasing Agricultural use of azoles: - A driving source of resistance. - 14% of environmental Aspergillus strains resistant to azoles in the UK - 7% of spores found in Eastern Himalayas are resistant to at least 1 medical azole

Answer 54

Can increase resistance to a drug by 1,000-fold. Self-made matrix constituted of polysaccharides and proteins Functions: -Protect fungi from the environment -Blocks immune cells: can’t reach the fungi with the sugar outside their hyphae

Answer 55

New molecules are in preclinical and clinical stages Repeats of same mistakes are in perspective **Ipflufenoquin** -Approved by US EPA 2023 -Able to select for resistant strains in the field, even though we haven’t actually started to use it in clinical settings

Answer 56

1. Losing antifungals 2. More people at risk (more immunosuppressed people) 3. Temperature rising: -Now only 6% of fungi can grow at 37°C today, but what about tomorrow? 4. Having to deal with new conditions helping fungal dispersion and disease.

Answer 57

• Critical Group • High Group • Medium Group

Answer 58

Critical group -90% resistant to at least 1 antifungal. -30% resistant to at least 2 antifungals. -4% resistant to everything (pan-resistance). -Fast spread all around the world. -Mysterious origin: 4 clades suddenly appeared around the world in 5 years. They are not from the same ancestor

Answer 59

1. Global warming: Allows strain to resist temperatures up to 42°C. 2. Ecological niche: -Rich in salt (resistance up to 10% NaCl) -Rich in antibiotics -Persistence facilitated on plastic pollutants. 3. Intermediate animal reservoir remains to be established -also climate change might lead to habitat shift, transmit the fungi pathogen in more regions

Answer 60

Ex. Trichophyton indotineae 全球扩散

Answer 61

Medium group Dimorphic fungi: Coccidioides immitis and Coccidioides posadasii. Cause Valley Fever -Pulmonary: pneumonia-like symptoms -Dissemination to the skin, lymph nodes, bones, joints, and CNS -40% of people inhaling spores become symptomatic, 1–5% experience dissemination. Spread to region with low humidity and high temp. -climate change increase its range

Answer 62

More unexpected pathogen appear to affect human

Fungi Flashcards

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