Fungi Midterm 3

animals and fungi are both

heterotrophs

heterotrophs

organisms that derive energy from the breakdown of complex organic food sources

autotrophs

derive energy from simple carbon sources, such as CO2

allergens

cause allergic reactions

mycotoxins

secreted fungal secondary metabolites that are toxic to humans at low concentrations, cause mycotoxicoses

mushroom toxins

poisons in mushroom hyphae (intracellular) that are toxic when ingested

fungal diseases

infectious fungi that cause diseases in humans (mycoses)

outdoor spore concentrations range from

200 - 1,000,000 spores per cubic meter

spore concentrations in the air are typically

100 - 1000 times greater than pollen levels

most fungal allergens are

type 1

immediate hypersensitivity

type 1 response, overactive response when fungal spores/hyphae are recognized as antigens triggering production of antibodies (IgE)

National Allergy Bureau (NAB)

creator of NAB scale for spore count risk, majority is often Cladosporium/Epicoccum/Alternaria/Ganoderma

Stachybotris

genus within Ascomycota, Pezizomycotina with common name Black Mold, can carry toxins that cause illnesses at high concentrations

indoor mold problem diagnoses indicators

indoor spore load > outdoor spore load, indoor spore type does not match outdoor spore types

tape mount

clear cellophane tape used to pull spores without losing spatial arrangement, transfer spores to glass slide for microscopy

Aflatoxin B1

produced by aspergillus flavus, source of the term “A-fla-toxin”, polyketide that causes liver failure and cancer, peanuts

Ochratoxin A

produced by aspergillus ochraceus and other fungi on coffee, polyketide that mainly causes kidney damage

Ergot alkaloids

produced in sclerotia produced by Claviceps species in cereal grains, causes ergotism

ergotism

St. Anthony’s fire, affecting nervous system and causes gangrene in extremities

Amanitin

produced by amanita phalloides (death cap), inhibits RNA synthesis (transcription), damages human liver

Phalloidin

produced by amanita phalloides, irreversibly binds to actin and disrupts cell structure, damages liver

Muscarin

produced by amanita muscaria (fly agaric), causes sweating/vomiting

Ibotenic Acid

psychoactive effects (along with muscimol) but content varies by region and strain

Coprine

produced by coprinus atramentarius (tippler’s bane), severe upset stomach and vomiting when mixed with alcohol, traditionally used in Antabuse to deter alcoholics from drinking

3 attributes of human disease-causing fungi

grow well at 37 C, flexible C/N metabolism & element scavenging, can recognize and adapt to host, some fungi bend these rules by attacking immunocompromised humans

Entomopathagens

pathogens of insects

Nemotophagy

pathogenic hunters of nematodes

chytridiomycoses

pathogenic chytrids

white-nose syndrome

pathogens of bats

superficial

colonization of skin/hair without invading skin or causing reaction

cutaneous

infection of skin/hair without invading skin but causing allergic response

subcutaneous

chronic infection of the skin and subcutaneous tissue via implantation

systemic: opportunistic

infection primarily of immunocompromised people

systemic: true pathogen

infection of healthy hosts via change in fungal morphology

implantation is accidental when

non-pathogenic fungi enters open wound

dandruff

basidiomycota yeast causing superficial dermatitis

candida albicans

most common fungal infection in humans, polymorphic yeast (ascomycota: saccharomycotina) part of natural microflora in humans but can cause cutaneous reactions/infections

monomorphic

always filamentous or yeast

dimorphic

switches between yeast and filamentous morphologies, many pathogenic fungi are dimorphic

polymorphic

includes a third morphology, pseudohyphae in candida

pseudohyphae

elongated, incomplete budding events where filaments lack connectivity, no pores

sporothrix species

rose handlers disease, sporotrichosis is subcutaneous infection where sporothrix is implanted under the skin

blastomyces dermatitidis

dimorphic yeast with very slow infection spread, begins with mild pneumonia and makes late detection an major issue, lives in wet decaying organic matter in river bottoms

histoplasma capsulatum

dimorphic yeast with very similar habitat and infection pathway as blastomycosis, some instance involve infection beyond lungs and into bone marrow and skin tissues

cryptococcus neoformans

anamorph of basidiomycota yeast, most often found in pigeons, inhalation hazard in lungs, cause cross blood-brain barrier, most important fungal pathogen threatening AIDS patients

pneumocystis jirovecii

causes certain type of pneumonia, taphrinomycota yeast with cholesterol rather than ergosterol, many drugs do not work due to lack of ergosterol,