micro lecture 2 - mycology

mycology

the study of yeast, molds, and mushrooms

are yeasts unicellular?

yes

are molds multicellular?

yes

are mushrooms multicellular?

yes

what kingdom do fungi belong to?

eukaryotes

where are fungi located?

air, soil, water

first characteristic of fungi

similar to algae; no chlorophyll

second characteristic of fungi

mainly aerobic or facultative

third characteristic of fungi

source of carbon + energy are organic compounds

fourth characteristic of fungi

absorption of food

what are some benefits of fungi?

food industry, antibiotics, decomposers of plant matter, medicinal, commercial, genetic engineering

is penicillium a fungi?

yes

trichoderma produces what enzyme?

cellulase

what are the medicinal benefits of fungi?

taxomyces sp.: taxol

aspergillus terreus: statins

tolypocladium sp.: cyclosporins

what are the commercial benefits of fungi?

trichoderma sp.: cellulase (clarify juice)

how are fungi used in genetic engineering?

yeast cells used to produce the hepatitis b vaccine; aspergillus sp. engineered with rennin gene

what are some undesirable effects of fungi?

food spoilage, plant disease, damage to buildings, animal diseases, human diseeases

what are examples of plant disease due to fungi

potato blight, dutch elm tree, chestnut tree disease

when damage is done to buildings by fungus, what is it called?

dry rot

what disease do bats get from fungal infections?

white-nose syndrome

what disease do humans get from fungal infections?

mycoses

what is the domain of bacteria?

bacteria

is bacteria prokaryotic?

yes

is bacteria unicellular?

yes

how does bacteria reproduce?

binary fission

are bacteria smaller or larger in size?

smaller

what is the cell wall of bacteria made of?

peptidoglycan

does the cell membrane of bacteria contain sterols?

no

what is the domain of fungi?

eukarya

are fungi prokaryotes or eukaryotes?

eukaryotes

are fungi unicellular or multicellular?

multicellular

how do fungi reproduce?

spores + budding

are fungi smaller or larger in size?

larger

what is found in the cell wall of fungi?

mannan, chitin, and glucan

does the cell membrane of fungi contain sterols?

yes

what areas do fungi prefer to grow in?

warm, moist areas (can also be dry)

at what rate do fungi grow?

slower than bacteria

what pH do fungi grow best at?

5

do fungi grow better in sugary or salty conditions?

both

what temperature do fungi grow best at?

room temperature

are fungi susceptible to heat?

yes

what do fungi metabolize best?

complex carbohydrates like lignin (wood)

why is yeast non-filamentous?

it is unicellular and reproduces by budding rather than hyphae

facultative

organisms that can grow with or without oxygen

is yeast facultative?

yes

what is the white, powdery coating on fruits and leaves?

yeast

how does yeast reproduce?

budding; can produce up to 24 new cells

psuedohypha

buds do not detach

dimorphic

cells are more pathogenic

how is dimorphism dependent on temperature?

at RT, yeast is mold-like. but at body temp, it is yeast-like

at what temperature is yeast mold-like?

25°C

at what temperature is yeast yeast-like?

37°C

vegetative structures of molds do what?

obtain nutrients

thallus

body of mold consisting of filaments

hyphae/hypha

filaments; can be very long; elongate at the tips

septa/septum

cross-walls

coenocytic hyphae

no cross-walls

mycelium

filamentous mass visible to the unaided eye

separate hyphae have what structures?

septum, pore, nuclei, cell wall

coenocytic hypha have what structures?

nuclei, cell wall

what grows from a spore?

growth of a hypha from a spore

molds are identified by what structures?

reproductive structures or spores

asexual spores

formed by hyphae of one organism (NO fusion of nuclei)

are asexual spores genetically identical to the parent?

yes

are asexual spores the product of mitosis or meiosis?

mitosis; occurs MORE often in nature

what is an example of asexual spores?

canidiospores (also known as conidia)

conidiosphore

supporting structure of a conidiospore

what two microbes are examples of conidiospores?

aspergillus sp. + penicillium sp.

aspergillus sp.

penicillium sp.

sporangiospores have what structures?

sporangium; sporangiophore

sporangium

sac

sporangiophore

supporting structure

what microbe is an example of a sporangiospore?

rhizopus sp. (mucor)

sexual spores

fusion of 2 nuclei from 2 opposite mating strains of the same species of fungi

sexual spores are made by mitosis or meiosis?

meiosis; occurs less often that asexual spores

medically important fungi will produce what types of spores in the lab?

asexual spores

medically important fungi will produce what types of spores in the body?

sexual spores

what are the types of sexual spores?

zygospores, ascospores, basidiospores

what is the first step in identifying fungi in the lab?

look for spores

cultures of fungi prefer what conditions?

sugary/salty; low pH; RT

mycotoxins

toxins/poisons produced by fungi; damage to kidneys, liver, nervous system

aflatoxin is produced by what microbe?

aspergillus sp.

where is aflatoxin found?

peanuts and corn fields

aflatoxin is dangerous to…?

humans + animals

aflatoxin causes damage to…?

the heart + liver

ergotism is caused by what microbe?

claviceps purpurea

where is ergotism (claviceps purpurea) found?

rye + cereal grains; crops; appears as a soot-like mass

ergotism was widespread during what time period?

middle ages; possible connection to the salem witch trials

ergot poisoning does what to the body?

restricts blood flow; causes hallucinogenic symptoms similar to LSD

mycoses (or mycosis)

fungal disease

mycoses can involve which 5 tissue groups?

superficial, cutaneous, subcutaneous, systemic, opportunistic

superficial mycoses

involves hair shaft + surface epidermal cells

piedra

superficial mycoses; found in tropical climates; causes cosmetic issues

what is a symptom of piedra?

hard black or white gritty nodules on hair shafts

what is the treatment for piedra?

shaving/cutting hair + miconazole (topical)

cutaneous mycoses

involves epidermis, hair, nails

dermamycoses

nail mycoses

tinea + ringworm infections colonize what parts of the body?

hair, nails, epidermis

keratinolytic fungi

fungi that target keratin (dermatophytes)