Mycology Flashcards
How did the discovery of penicillin come about?
First antibiotic isolated from fungi - occured during WW1 due to high bumber of slodiers dying from infections.
By Fleming
Symptoms of infection that was experimentally treated by penicillin?
Rapidly progressing rash on face, eyes and scalp, high spiking fever
Symptoms of Mucromycosis
Eye pain - protuding eye
Black patches - lesions that progress to skin (diagnosable)
Coma due to abscesses in the brain
Death by cardiac arrest
Properties of mucormycosis
-Invasive, primitve, rapid progression
-requires exogenous iron
-frequent in diabetics and iron chelation therapy
-highly drug resistant
Overall bad sides of fungi
Causes infection, intoxication and allergy
Overall good side of fungi
Use in the pharmaceutical industry, food industry, biodegradation….
Species numbers / discovery rate
Highly unknow, widespread
thought to be 1.5-12 million species
150,000 identified
discovery rate of 1000-2000 a year
Prokaryotes or eukaryotes? Why
Eukaryotic:
-contain nucleus
-protein secretory pathways
-mitochondrion (like animals)
-vaculoes (like plants - no chloroplasts)
-cytoplasmic membraine contrains ergosterol (animals have cholesterol, plants have sterol mix)
Describe the cell wall of fungi (+role)
Chitin based, its the exoskeleton of the fungi - different for every fungi, but all chiting based (mostly polysaccharides
Structure, protection, exchange with environment
Properties of the way fungi get their nutrients
-Heterotrophs - must absorb nutrients, can’t make them themselves
-no vasculature system - can’t spread their nutrients across their body, so ingest, puke reingest (external digestion)
Sub classes of fungi heterotrophy
-Sapotrophs: feed on dead organic matter
-Parasite: need a hsot
-Symbiont: partners with an organism
-Predators: trap and kill other organisms
Two types of fungi
Yeasts (gorwth as independent cells) & molds (multinucleated tubes)
Properties of yeast? (cell type, reproduction, transition)
Unicellular organism with one nucleus
Reproduction by budding or fission
Environmental signals can trigger transition to hyphae or pseudohyphae
Properties of mold? (cell type and structure)
Multicellular, filamentous tubular structure containing multiple nuclei
Hyphae - can contain septa (further branching - septated hyphae) or not (aseptated hyphae) assembled into mycelium
Hyphae definition
each of the branching filaments that make up the mycelium of a fungus.
Mycelium definition
the mass of branched, tubular filaments (hyphae) of fungi.
Fungal sexuality?
Fluid - can be sexual or asexual or parasexual (basically a combo of mitosis and meiosis)
Advantages of asexual reproduction + name of form
No need for a partner, maintains valuable genetic combinations
Reproduction by mitosis
Anamorph
Sexual reproduction (name of form + subclasses)
By meiosis
Telemorph - can be heterophallic or homophallic
Taxonomy key?
phylum -mycota
subphylum -mycotina
class -mycetes
3 main groups of fungi
Zoosporic fungi
Zygomycetous fungi
Dikarya subkingdom
General info: zoosporic
-primitive aquatic fungi
-not predators
-anchroed via rhizoid strcutre
-spread via zoospores (asexual)
General info: zygomycetous
-adapted to life on land
-sapotrophs
-aseptated filamentous fungi
-spead via zygospores &/or sporangiospores
General info: dykaria (2 types
-Ascomycota : spread via ascospores and conidia
-Basidiomycota: spread via basidospores
Both -s eptated filamentous fungi or yeast
Two main fungal spore dispersal strategies
Via animals or wind
Example of animal attraction (for fungi motility)
Stinkhorn fungus: grows up to 25cm, penetrating, strong
produces a sticky spore mass that smells like rotting meat, attracts flies that carry spores
Example of animal control (for fungi motility)
Cicadas and fungi - emerge every 13-17 years, infection causes loss of abdomen and fertility, but increased sex drive causing infection by mating attempts
How doe fungi use the wind? What type of fungi + explain the process
Sporulation
Via basidiospore formation, release and transport (wind uptake)
Basidiomycetes
What increases the number or spores formed (3)? And their dispersion(2)?
Formation: Number of folds
-Gills
-Pores
-Folds
Dispersion:
-Increased surface area and elevation
Name of basidiospore release process? Explain
Ballistospory - surface tension catapult
-Swelling of bullers drop from the apiculus
-Contact with the swelling of the water layer over the basidiospore
Surface tension causes the basidispore to be flung
**preference of mushrooms to humid environments
How far can spores travel by the wind? How does it work post release?
cms to kms
The air is cooled below the fungi due to water evaporation
Gravitational free fall pulls spores into the air convection cell (carried by cold air - pushed along by wind)
Is sporulation sexual or asexual?
Generally sexual
Name of another fungi based transportation method (other than wind)
Catapulted by osmotic pressure
In what major way is fungi still shaping our environment? Name of fungi, process
Cntribution to amphibian mass extinction event
Chytrids - dangerous invasive fungi
Kills by disurpting skin functions, leading to cardiac arrest
What is fuelling the spread of chytrids? Origin
Amphibian mass extinction event
International animal trade
Originated in Asia
Result of amphibian mass extinction that is contributed to by fungi?
Clsoe to 100 species extinct - chytrids are largest threat to a animal diversity
What effect does the amphibian mass extinction event have on human population?
Frogs have a positive effect on human disease by consuming parasitic infections that reside in bugs
Alberta: effect of fungi on plants
Dutch elm disease (fungal disease) spreads through the forst in Alberta
**Blue stain fungus
Spread by beetle carries that burrow into the trees, spreading fungal spores
Fungus colonizes the tree phloem and sap, leading to death
Mont-royal: effect of fungi on plants?
Removal of trees to prevent illegal behaviour
Degradation of mountain
Replanting with fast growing norway maples - susceptible to tar spot (fungal disease)
Predatory - norwegian maples displace native trees
What is white nose syndrome?
Fungal infection living in bats (hosts)
Mycovirus causing 5 mill bat deaths per year
*no mass mortality in europe
Infects during hibernation, controlled during waking, takes back over when bats go back to sleep
Relevance of bats to the food industry? (+ relationship to fungus)
300++ fruit trees depend on bats for pollinization - white nose syndrome is not yet reported to have crossed over
Insect population control issue due to mass mortality of bats
Effect of bat mass mortality on human health?
Decreased bats
Increased insect control issue
Increased pesticide usage
Increased infant mortality
Relationship between monocultures and fungal infections?
Example?
-Monocultures are prone to fungal infections due to being genetically uniform and concentrated in specific areas, which can lead to fungal epidemics.
-Banana monoculture (herbs, soproduce fruit withot fertilization, so not sexual reproduction, so no genetic diversity)
1) One banana species type was spread worldwide (gros michel)
2) decimated by TR1 from soil fusarium wilt) - clogging of roots and xylem vessels -> loss of vasculature -> plant wilting and death
3) Same story with cavendish, death by TR4
What is wheat rust?
Basidiomycota, affects wheat in the summer (asexual reproduction) swtiches hsot for the rest of the year to barberry plants (sexual reproduction)
Widespread destruction of wheat crops in the UK
Solution: removal of barberry bushes (worked)
But conservationists replanting barberry for insect survival have brought it back
What is mycorrhizal fungi?
Micorrhizae = symbiotic relationship between plants and fungi
80% of plants, usually with glomeromycotina (zygomycetous)
Increases nutrient access to roots
What are the 4 types of mycorrizhal interactions?
Arbuscal & ectomycorrhizae (main)
Orchid & ericoid (specific)
Explain arbuscal and ectomycorrhizae fungi interaction
Fungal structures cover the root (diff strcutres for the two types but same idea): exchange zone
Plants provide C to fungi
Fungi improve the wate and mineral assimilation
What do myccorhizal fungi secrete and what does it do?
Secretion of glomalin (hydrophobic glycoprotein) into soil
Improves soil structure, carbon sequestration, water flow and availability, biodiversity, heavy metal adsorption….
Link between mycorrhizal fungy and immunity?
(Still in plants btw)
Pathogen presence prevention
Stimualtes plants general health and metabolic activity
Stimulates plant defences
Grey mold - effect on food industry + name
Botrytis
(-) 10 billion dollars in crop loss
(+) Southern france wine (Sauternes) : infection weakens the skin allowing for water evaporation and sugar concentration *must be picked at exactly the right time
Three types of grapes in Sauternes wine
-Semillion (main grapes)
-Sauvignon blanc (acidity)
-Muscadelle (floral note - easily infected by grey mold)
Cheese and fungi?
Blue cheese- fungi is critical for maturation by proteolysis of dairy proteins an dlipids, with falvour coming from the secretion of seconday metabolites
Process for obtaining secondary metabolites? Why?
Sexual reproduction of penicilling to increase cheese variety
Angel death? Toxin type, location, properties, lethal dose, cause of death
-Contains cyclopeptide toxins (amatoxins)
-Quebec
-Heat stabke, unaffected by drying
-Responsible for almost all mushroom poisoning
-0.1mg/kg (with up to 15mg per cap
-Inhibits RNA pol II (protein synthesis inhibition) - liver failure
Two mushroom type causing psychoactive toxins? Where do they impact?
Psilocybin and psilocin
Impact bladder, GI tract, muscles as well as the brain (effect on perception)
How does psilocybin work? Used in clinical trials for?
Agonist at cortical serotonin 5-HT 2A receptor
(mimics serotonin)
Depression and PTSD
What psychoactive fungus is hosted by rye? What can it be combined with to make _____
Ergot fungus: lysergic acid can be combined with diethylamine to make LSD
What is ergot fungus hosted by? History of the psychoactive drug?
Rye
Link to the salem with trials
Napoleon and fungus?
Died of arsenic poisoning caused by fungus
Cupric arsenic + fungi allowing arsenic to be in the air = Gosio’s disease
Fungi use as medication?
Canadian first nations people use fungi in traditional medicine
Secondary metabolites have health benefits for arththritis, headaches, sunscreen, eye drops, nosebleeds (+++)
Summary of fungal secondary metabolites?
Extremely diverse group of compounds, exploited for commercial and medical applications
Minority still remain as major health and economic concerns
Two types of fungal infections (examples)
Superficial - most common, often benign. Common in immunocompetent (e.g. ringworm)
Invasive - rare and lethal if untreated, common in immunocompromised (e.g. mucormycosis)
What causes Tinea unguium and tinea pedis? Treatment and frequency
Provoked by dermatophytes (tinea) that feed on keratin
Unguium: fingernails, 5-10% of the population 3-6months of antifungals
Pedis: feet, most common fungal infection in humans, topical antifungal therapy for 10-14 days (often reoccurs)
Three possible environmental origins for superficial fungal infections?
Anthropophile, zoophile or geophile
What is candida albicans? Progression,where
Superficial fungal infection
Yeast cells -> pseudophya -> true hyphae (causes infection)
Commensal organism (until morphological switch to virulence) in GI tract, mouth and vaginal flora
Three infection types caused by candidas albicans
Oral thrush
diaper dermatitis
vaginal candidiasis (female) balanitis (male)
Three clinical classifications of invasive infections?
Yeasts: systemic disease, pulmonary disease absent or subclinical
Molds: primary pulmonary disease with dissemination less common
Dimorhpic fungi: pulmonary disease with dissemination as prominent part of the disease (spread)
What is candedimia and how does it work? Example? Mortality?
Severe yeast bloodstream infection
Yeast reached blood flow to access other organs
Generally immunocompromised patients
Fatal if untreated - mortality rate of 20-50%
Average stay at the hospital 2-8 weeks
What are the three strands of cryptococcus yeast infections? Where do they occur from?
Basidiomycota
Encapsulated yeast
Two common sp
From the environment: soil, eucalyptus trees, bird droppings
What is cryptococcosis? How do you get it? Treatment? Symptoms?
Invasive yeast infection caused by breathing yests or spores
immuno competent and compromised at risk, causes pulmonary infection (25-50% are asymtpomatic)
CSF puncture for cryptococcal meningitis
What is cryptoccocal meningitis? How does it happen, whats the treatment
fungal infection that affects the brain and spinal cord
cryptococcosis sits in macrophages to cross the BBB
Disproportionately likely in HIV patients
Treatment:
1. Induction (1 week of amphotericin B)
2. Consolidation (high dose of fluconazole)
3. Maintenance (low dose of fluconazole for a year)
How did cryptococcus start affecting immunocompetent people?
New species rising from same sex mating (started in Canada)
Symptoms + info on cryptococcus gatti
> 300 human, >400 animal cases
appeared in 1999 causing pneumonia and meningitis in immunocompetent patients
infects native trees and soil
What are characteristic properties of mold infections?
What is the most common type?
opportunistic, aggressive and destructive
Aspergillus, causing invasive pulmonary aspergillosis (>80% mortality
Most common species of aspergillus + properties
Aspergillus fumigatus
Asexual spores are called conidia
Inhaled on a daily basis, but generally taken care of by the immune system and the mucociliary elevator
What is the progression of aspergillus fumigatus in immunocompromised patients or patients with imapired lung function?
Alveolar infection -> germination -> angioinvasion -> lung propagation
Characteristics of dimorphic fungi?
Example
Infect immunocompetent people, geographically restricted in range
Blastomyces dermatis
Explain the infection cycle + symptoms of blastomyces dermatis
Dimorphic fungi
Environmental form in wood (major dog pathogen), endemic to great lakes and mississipi valley
The host-associated form is a parasitic yeast, starting as a lung infection and disseminating to the blood and then organs
Low mortality, but secondary cutaneous infections are common
Overall effect of climate change on fungal infections?
Will become increasing more frequent
Why are finding antifungals challenging?
Fungi are eukaryotic proteins - there isnt much we can target that wouldn’t also target metabolic proteins
What are the two targets of antifungals?
The chitin wall and ergosterol
What in the chitin wall do antifungals target? Name of the drug family
chitin and beta-1,3-glycan
echinocandins
What do echinocandins do? Effect on yeast and molds
Cell was inhibitors by inhibiting beta-1,3-glycan
First line of defense against active yeast infection- fungicidal effect
Fungistatic (stops growth but does not kill) molds
How do antifungals target ergosterol?
What are the two antifungal families
By blocking ergosterol, membranes become too rigid
Polyenes and azoles
How do polyenes work? When is it used, dosage
Binds to ergosterol, causing accumulation, making holes in membrane
Braod spectrum, used against severe cases of invasive infections
1mg/kg/day every 2-4h
*very poor effect on metabolism
How do azoles work? effect on yeasts and molds, chemical composition
Inhibit ergosterol synthesis
Fungicidal to molds
Fungistatic against yeasts
contains either an imizadole or a triazole group
What is the common feature of all antifungals?
Resistance of fungus to them is increasing
What main component of fungi allow them to resist drugs?
Biofilms - protection against outside microorganisms and the environment
What is the driving source of resistance to azoles?
The use of azoles to kill mold in agriculture - same as the ones used in medical fiels, and the more its used the more fungi become able to resist azole in all settings
What are tehe three categories of priority groups for pahtogens? Published by who?
Critical, high and medium
WHO
What is the ‘superbug’ appearing in the critical group? Whats the worry?
Candida auris - massive, rapid global spread since first report in 2009
4 clades, unlikely to be of the same origin due to phylogenetic diversity
What is the hypothesis surrounding the origin of candida auris?
Global warming allowed the strain to be more resistant, as well as increased the presence of its ecological niche (rich in salt, antibiotics for resistance, and persisiting on plastic pollutants)
brought to rural areas by an unknow animal reservoir, then urban
Pathogen in medium group covered in class? Symptoms, affected group, affected region, why is it worrisome
Valley fever: dimorphic fungi (Coccidiodes spp.)
Pulmonary + dissemination
40% of people inhaling the spore become symptomatic (high risk to afroamerican and filipino people)
Southwest USA - low humidity + high temp
Likely to spread with climate change
What is disaster microbiology
study of how natural and human-made disasters affect microorganisms, and how these changes impact ecosystems and human health
